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2023 (vol. 23)

Chapter 1 - Preliminary investigations on the Zard Formation at its type locality (North Khorasan Province, Iran)
Bruno GRANIER, Seyedeh Saeideh S. MORTAZAVI, Morteza TAHERPOUR-KHALIL-ABAD & Farokh GHAEMI

 | HTML  | PDF [5,168 KB]  | DOI: 10.2110/carnets.2023.2309

 Abstract:  This chapter presents a revision of the Zard Formation in its type area, i.e., in the North Khorasan Province (Iran), including at its type locality. It comprises a description of the sedimentological and micropaleontological criteria that permit it to be distinguished from the Mozduran Formation (below) and the Tirgan Formation (above). At its type locality, its lower boundary is a heavily bored surface. Actually, both contacts with the framing formations correspond to transgressive surfaces, which imply that this lithostratigraphic unit is an Unconformity-Bounded Unit. With respect to biostratigraphy, this formation contains a few second-order markers: Holosporella sugdeni, Kopetdagaria sphaerica, and Torinosuella peneropliformis, which are also found in the unit above, i.e., in the Tirgan Formation. Because the latter contains markers that first appear in the Barremian: Bakalovaella elitzae, Pseudoactinoporella iranica, and Balkhania balkhanica, but also Montseciella arabica, the total range of which spans the Upper Barremian, the Zard Formation (i.e., the Zardian regional stage) should partly covers the Hauterivian to Barremian interval. Finally, although it cannot be definitely excluded that the lowermost part of the Zard Formation could be Valanginian in age, this option still requires proper documentation.

Carnets Geol., vol. 23, no. 9, p. 161-189

Online since September 10, 2023


A new pseudolepidinid foraminifer, Hanovolepidina browni gen. nov. sp. nov., from the middle Eocene (mid-Lutetian) of Jamaica and its significance
Simon F. MITCHELL

 | HTML  | PDF [3,090 KB]  | DOI: 10.2110/carnets.2023.2308

 Abstract:  The new larger benthic foraminifer, Hanovolepidina browni gen. nov. sp. nov., is described from the Chapelton Formation (mid-Lutetian, middle Eocene, ABZ7) of Jamaica. The genus shows the characteristic transition from a single to double equatorial layer about mid-way across the radius as seen in axial sections that characterises the family Pseudolepidinidae. Equatorial sections show the embryo followed by 4 or 5 spiral rotaliid chambers with the last chamber giving rise to a primary spiral and secondary (counter-) spiral of equatorial chambers. The presence of a long rotaliid stage suggests a more primitive form that Pseudolepidina, and Hanovolepidina gen. nov. differs also from the latter in lacking the extra principal accessory chamber seen in axial section. Hanovolepidina gen. nov. is provisionally suggested as an ancestor of the late Eocene Triplalepidina. The new discovery demonstrates a greater diversity of the family Pseudolpeidinidae in the Caribbean that previously recorded, although occurrences of this family are very restricted stratigraphically suggesting that it may appear in the region due to migration events.

Carnets Geol., vol. 23, no. 8, p. 149-159

Online since August 27, 2023


Nomenclatural Note, p. 160


Hiatuses and redeposits in the Tithonian-Berriasian transition at Le Chouet (Les Près, La Drôme, SE France): Sedimentological and biostratigraphical implications
Bruno R.C. GRANIER, Serge FERRY & Mohamed BENZAGGAGH

 | HTML  | PDF [4,420 KB]  | DOI: 10.2110/carnets.2023.2307

 Abstract:  Our new study of the Tithonian and lower Berriasian succession of Le Chouet (Les Près, La Drôme, France) better characterizes the lithological succession, the macro- and microfacies, and the stratigraphic ranges of some microfossils mostly calibrated on the calpionellid biozonation. On the lithological side, the Tithonian strata are dominantly characterized by thick-bedded breccias representing debris flows and related calciturbidites whereas the Berriasian strata are typically white limestones that also comprises scattered intercalations of thin-bedded breccias and calciturbitides (including cryptic mud calciturbidites). In thin sections, these white limestones display mud- to wackestone textures and their allochems are mostly tiny bioclasts (e.g., radiolarians, calpionellids, saccocomids). Breccias are lithoclastic rudstones and/or floatstones with a matrix similar to the calciturbidites. Their lithoclasts are either extraclasts sensu stricto (i.e., material derived from updip shallow-water areas) or pseudointraclasts, representing reworked subautochthonous material (i.e., mud- and wackestone lithoclasts with radiolarians, saccocomids and/or calpionellids). In addition to the erosional features observed at the bases of the gravity flows, these pseudointraclasts document the intensity of submarine erosion. Locally they help to estimate the depths of erosion updip of the deposit. A number of bioclasts are reworked from updip shallow-water areas; among them, it is worth mentioning the foraminifer Protopeneroplis ultragranulata (Gorbatchik), the first occurrence of which is dated to late early Tithonian. Saccocomids are part of the dominating pelagic biota reported from the lower and lower upper Tithonian interval whereas calpionellids replace them in the uppermost Tithonian to lower Berriasian interval. Intervals with saccocomids characteristic of zones 4-5 and zones 6-7 are respectively ascribed here to the lower Tithonian (4-5) and pro parte to the upper Tithonian (6-7). The biozonation of the calpionellid group sensu lato allows identification of the Boneti Subzone of the chitinoidellids, the Crassicollaria Zone with its four subzones (A0-A3), and the Alpina Zone with its first subzone (B1). On the basis of biostratigraphical and sedimentological data (including the rates of sedimentation), most zonal boundaries are located at the erosional bases of breccia or turbidite layers and thus coincide with hiatuses.

Carnets Geol., vol. 23, no. 7, p. 123-147

Online since June 27, 2023


Gzhelian (latest Carboniferous) Pseudoacutella partoazari foraminiferal assemblage from the Tabas Block (Central Iran)
Hamed YARAHMADZAHI & Daniel VACHARD

 | HTML  | PDF [1,906 KB]  | DOI: 10.2110/carnets.2023.2306

 Abstract:  A foraminiferal assemblage is reported from the Zaladou Formation in the Tabas Block (Shishtu Section), Central Iran. This assemblage comprises 16 species belonging to 14 genera, and encompasses the fusulinids Pseudoacutella partoazari, Grovesella tabasensis, Gr. aff. australis, Gr. sphaerica, Gr. sphaerica var. quadrata, Gr. cf. staffelloides, Schubertina sp., Schubertella sp., and the smaller foraminifers Eotuberitina sp., Lasiodiscus tenuis, Raphconilia cf. minor, R. multihelicis, R. modificata, Tetrataxis cf. parviconica, Globivalvulina ex gr. bulloides, Gl. graeca, Calcivertella heathi, Tansillites sp., Palaeonubecularia? sp., Hemigordiellina sp., Nodosinelloides longa, and N. longissima. The age of this assemblage is considered to be Gzhelian. The assemblage is dominated by the fusulinid Pseudoacutella partoazari with a low total diversity of smaller foraminifers. This assemblage is compared to similar assemblages in other parts of Iran and well as the USA. An evolutionary lineage of Pseudoacutella partoazari is also proposed. It is confirmed that Pseudonovella differs from Pseudoacutella by the periphery rounded-carinate (carinate in Pseudoacutella), pseudochomata less developed, and the type of coiling (Pseudoacutella is truly planispiral involute). Pseudonovella is suggested here as the ancestor of Pseudoacutella. This assemblage bears one unusual attribute, the overwhelming dominance of the fusulinid Pseudoacutella and the relatively low total diversity, compared with similar foraminifera from Alborz, Sanandaj-Sirjan, Sabzevar and central Iran, which present warm and humid conditions during the Late Carboniferous.

Carnets Geol., vol. 23, no. 6, p. 107-122

Online since June 30, 2023


The first record of Middle Jurassic serpulids from SE Turkey, equatorial Tethys
Olev VINN & İzzet HOŞGÖR

 | HTML  | PDF [846 KB]  | DOI: 10.2110/carnets.2023.2305

 Abstract:  The Jurassic platform margin succession in the Hezan area, called the "Hezan Unit" (Diyarbakır), on the north of the Arabian platform in southeastern Turkey includes five formations of carbonate-dominated rocks. The most interesting is the upper part of the Hezan unit (the Kuran Formation) that contains unique layers of oolitic and clayey limestone. A first record of the calcareous polychaete tubeworm Propomatoceros lumbricalis is described from the Middle Jurassic lower part of the Kuran Formation of the Hezan area. Most knowledge of fossil serpulids is centered on European material, and little has been done on Middle East fossil calcareous tubes. The taxonomic information recorded as a result of this study will add to our understanding of the biogeographic history of the Middle Jurassic calcareous polychaete associations and help to interpret the structure and paleoecology of its marine communities.

Carnets Geol., vol. 23, no. 5, p. 97-105

Online since June 30, 2023


Upper Triassic (Norian-Rhaetian) Foraminifera from the Nayband Formation of the Lut Block (Garm Ab section, Northeast Iran)
Fatemeh AMIRHASSANKHANI, Baba SENOWBARI-DARYAN & Koorosh RASHIDI

 | HTML  | PDF [3,997 KB]  | DOI: 10.2110/carnets.2023.2304

 Abstract:  Studies of Nayband Formation from the Garm Ab section in Lut Block in Central Iran led to the identification of 26 foraminiferal taxa. Nine species are reported from Iran for the first time: Involutina ex gr. liassica (Jones), Involutina sp., Lamelliconus permodiscoides (Oberhauser), Palaeolituonella cf. meridionalis (Luperto), Palaeolituonella cf. angulata Senowbari-Daryan & Cacciatore, Gaudryinella cf. kotlensis Trifonova, Ammobaculites eumorphos Kristan-Tollmann, Frondicularia rhaetica Kristan-Tollmann, Frondicularia cf. xiphoidea Kristan-Tollmann, and Orthotrinacria ? expansa  (Zaninetti et al.). The taxa restrict the Upper Triassic interval to probably just the Rhaetian. Based on the foraminifera and their abundance, three different association-types could be distinguished, i.e., the Decapoalina schaeferae-Miliolipora cuvillieri, Trocholina turris-Agathammina iranica and Involutina ex gr. liassica-Trocholina umbo associations. Comparisons of foraminiferal associations in different parts of central Iran, such as 1) Hassan Abad section, SW of Ferdows in Lut Block, 2) the type locality of the Nayband Formation in Tabas Block, NE of Esfahan in the eastern part of Central Domain Block, and 3) the Garm Ab section in Lut Block, indicate that the hyaline foraminifers are most abundant in the Garm Ab. Besides, in the Lut Block, the reef environments in the Garm Ab section are deeper water than those of the Hassan Abad section. The association of Trocholina umbo with Miliolipora cuvillieri is similar to the foraminiferal association from the NE of Esfahan and shows similar conditions in Lut Block and Central Domain Block. The two assemblages of hyaline foraminifers, especially the new report of Involutina and Trocholina, prove to be Rhaetian in age.

Carnets Geol., vol. 23, no. 4, p. 77-95

Online since April 1, 2023


Late Miocene biostratigraphy and paleoenvironment of the Sais Basin (southern Rifian Corridor, Morocco): New insights from the Moulay Yakoub area
Soukaina TARGHI, Nadia BARHOUN, Naima BACHIRI TAOUFIQ, Mohamed ACHAB, Rachid ESSAMOUD, Hanane BAHAJ, Jihad RAHMOUNA & Naima BERRY

 | HTML  | PDF [1,318 KB]  | DOI: 10.2110/carnets.2023.2303

 Abstract:  During the Late Miocene, the Rifian Corridor was one of the two main corridors allowing exchanges between the Atlantic and the Mediterranean Seas. Sedimentary records accumulated along this corridor and specifically, in the Sais Basin, constitute case-study material for understanding the impact of the South Rifian Corridor on the evolution of the fauna, phytoplankton and environment during the Late Miocene. In order to reconstruct the evolution of marine paleoenvironments in the Moulay Yakoub region and to compare this evolution with other areas of the Sais basin, we conducted an integrated biostratigraphic and palynological study of the Upper Miocene of borehole KA 102. High-resolution biostratigraphy based on planktonic foraminifera revised and defined the chronostratigraphic framework of the Upper Miocene sedimentary series of the Moulay Yakoub region providing an age of 7.8 Ma to 6.52 Ma (Late Tortonian to Early Messinian). In the Late Tortonian, the planktonic foraminiferal assemblages suggest an open and relatively deep marine environment. At the Tortonian/Messinian boundary, planktonic foraminiferal and dinoflagellate associations, as well as distal indices, suggest a relatively deep and neritic distal marine environment with a decrease in diversity and an increase in reworked taxa. Surface waters are warm with a minor cooling trend observed just below this boundary. In comparison to previously studied sections in the Sais Basin, the Lower Messinian is characterized by a deeper and more distal marine environment. However, proximal trends and warm surface water conditions persisted in all studied areas from the basin during this period.

Carnets Geol., vol. 23, no. 3, p. 53-75

Online since April 1, 2023


Peculiar tube-like bivalve with densely packed concave tabulae (Štramberk Limestone, Tithonian-Berriasian)
Olev VINN, Bogusław KOŁODZIEJ & Zuzana KOZLOVÁ

 | HTML  | PDF [1,263 KB]  | DOI: 10.2110/carnets.2023.2302

 Abstract:  The fossils described here are from the Tithonian-lower Berriasian Štramberk Limestone of the Czech Republic. The specimens consist of densely packed, straight to slightly curved short tubes. Each tube is composed of a single valve rather than two valves. Some tubes show constrictions in the wall, generally on just one side. The lumen is almost completely filled with numerous densely packed slightly to strongly concave tabulae. In some tubes, the tabulae form complete internal floors while in others they connect to the wall with another tabula or seal the concavity in the underlying tabula. The tubes somewhat resemble tubeworms, rudists, vermetids and calcareous algae. However, based on morphological similarities such as the tube-like morphology in longitudinal section and the shapes of the lamellae and tabulae, these tubes resemble oysters described from the Albian of Brazil. Accordingly, we infer that the Štramberk tubes represent oysters or oyster-related bivalves.

Carnets Geol., vol. 23, no. 2, p. 43-51

Online since February 15, 2023


Issues in the identification of the Aptian/Albian boundary in South Atlantic basins and beyond
Ricardo L.M. AZEVEDO, Rogério L. ANTUNES & Mauro D.R. BRUNO

 | HTML  | PDF [2,009 KB]  | DOI: 10.2110/carnets.2023.2301

 Abstract:  The use of taxonomic-phylogenetic criteria established for planktonic foraminifera in the 2000's and the definition of the Albian Global Stratotype Section Point (GSSP-Alb) have resulted in a major change in the interpretation of the carbonate sections overlying the giant layer of salt present in basins of the South Central Atlantic (CSA) and their equivalent strata in the Equatorial South Atlantic (ESA), and interior of northeastern Brazil (BNE). These post-salt carbonates have long been considered Albian in age, but they contain a planktonic foraminifera association characteristically Aptian. Great conflicts arise, however, when this faunal association is compared with biostratigraphic successions based on other fossil groups or with lithostratigraphic and geochronological data. Controversies similar to those observed at sites 363 and 364 of the Deep Sea Drilling Project (DSDP) leg 40, drilled almost 45 years ago, have resurfaced. Thus, it is paradoxical that the remarkable disappearance of large species of planktonic foraminifera, associated with the top of the Paraticinella rohri Zone (of the upper Aptian), occurred stratigraphically above a typical Albian calcareous nannofossil succession (as the First Stratigraphic Occurrences of Hayesites albiensis, Tranolithus orionatus, Axopodorhabdus biramiculatus, and Eiffellithus turriseiffelli) or the FOs of three known species of pelagic calcispheres, all assumed to be of Albian age. Another notorious conflict lies in the fact that these carbonates rest directly on the salt layer onlapping the South Atlantic Middle Barrier (SAMB), where trachyandesite has been dated at 113.2 ± 0.1 Ma, identical to the value established for the GSSP-Alb. Detailed examination of 16 stratigraphic sections from around the world shows that the difficulties of fully applying the GSSP-Alb criteria are not limited to the CSA, ESA, and BNE basins. The explanation of these controversies may lie in the specific conditions of the water mass of the primitive South Atlantic that may have influenced morphological alterations or affected the temporal amplitude of taxa. But until geochronological, biostratigraphic, and lithostratigraphic incompatibilities can be clarified, it is here recommended to use the base of the evaporitic layer as the reference for the Aptian/Albian transition in CSA, ESA, and BNE basins.

Carnets Geol., vol. 23, no. 1, p. 1-42

Online since January 1, 2023


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2022 (vol. 22)

New larger benthic foraminifera from the subsurface Lower to Middle Eocene Oldsmar Formation of southeastern Florida (USA)
Edward ROBINSON & Kevin J. CUNNINGHAM

 | HTML  | PDF [1.719 KB]  | DOI: 10.2110/carnets.2022.2221

 Abstract:  We describe two larger benthic foraminiferal taxa collected from wells drilled in the subsurface Eocene rocks of southeastern Florida that are new to peninsular Florida and the Caribbean region. Saudia floridana n.sp. is characteristic of a foraminiferal assemblage, along with Helicostegina gyralis, wide forms of the Cushmania americana group, and Gunteria floridana, in an upper part of the Oldsmar Formation. Globogypsinoides browardensis n.gen. n.sp. occurs in a second foraminiferal assemblage, along with Borelis cf. floridanus, Coskinolina cf. yucatanensis, and as-yet undescribed large rotaliids, in a middle part of the Oldsmar Formation. The foraminiferal assemblage of the middle Oldsmar unit is ascribed an Ypresian age and the assemblage of the upper Oldsmar unit a Lutetian age. These two assemblages indicate inner shelf water depths of 40 m or less on the Florida Platform during the Early to Middle Eocene deposition of the middle to upper part of the Oldsmar Formation.

Carnets Geol., vol. 22, no. 21, p. 857-865

Online since December 25, 2022


Nomenclatural Note, p. 866


Just a different place to graze? An unusual occurrence of the echinoid feeding trace Gnathichnus pentax on a marine vertebrate coprolite (Miocene, Italy) and its palaeoethological implications
Alberto COLLARETA, Emanuele PERI, Stephen J. GODFREY & Giovanni BIANUCCI

 | HTML  | PDF [486 KB]  | DOI: 10.2110/carnets.2022.2220

 Abstract:  Faeces produced by marine vertebrates and macro-invertebrates contain sufficient organic matter to represent a usable food source for a wide array of macroscopic animals. In some extant marine environments, coprophagy even represents a crucial trophic interaction in food webs. In ancient ecosystems, coprophagy by macroscopic animals is occasionally exemplified by coprolites that exhibit biting traces or burrows. Here, we report Gnathichnus pentax on an exquisitely preserved vertebrate-bitten vertebrate coprolite from the marine calcareous deposits of the Pietra leccese (Miocene, southern Italy). This unusual occurrence is interpreted as evidence of the feeding activity of a regular echinoid; in particular, it may represent either exploratory coprophagy or the browsing of an algal (microbial) film that locally developed on the exterior of the faeces. Strengthening the former interpretation, the development of microbial communities on submerged faeces often leads to their destruction; furthermore, some extant Antarctic echinoderms are well known to ordinarily feed on vertebrate faeces, and coprophagy is believed to be fairly widespread among sea urchins. Supporting the algal browsing hypothesis, in turn, only a limited area of the external surface of the faeces was subject to grazing, and the resulting trace is neatly defined, which suggest that the feeding sea urchin targeted a precise location on the dung's exterior when the latter was already rather firm. To our knowledge, the G. pentax specimen studied here represents the first published record of this ichnotaxon on a coprolite.

Carnets Geol., vol. 22, no. 20, p. 847-855

Online since December 25, 2022


Miocene-Holocene paleoenvironmental changes in the Tinto River estuary (SW Spain) evidenced by sedimentology, geochemistry and fauna
Manuel ABAD, Marta ARROYO, Francisco RUIZ, María Luz GONZÁLEZ-REGALADO, Joaquín RODRÍGUEZ VIDAL, Luis Miguel CÁCERES, Tatiana IZQUIERDO, Antonio TOSCANO, Paula GÓMEZ, Gabriel GÓMEZ & Verónica ROMERO

 | HTML  | PDF [1,307 KB]  | DOI: 10.2110/carnets.2022.2219

 Abstract:  This paper investigates the paleoenvironmental evolution of a long core extracted in a small cove located in the Tinto-Odiel estuary (SW Spain). The inferred reconstruction is supported by sedimentological, geochemical, paleontological data and dating. Seven phases have been identified, with the transit from Late Neogene marine environments to a subrecent freshwater pond and a final anthropic filling. On the basis of these data, this area was flooded during the maximum of the MIS-1 transgression (6.5-5.2 cal. kyr BP), with the temporary presence of a subtidal channel with phanerogam meadows. During this evolution, three geochemical peaks have been detected, which correspond to 1) the first evidence of mining activities (~4.5 cal. kyr BP), 2) an interval of intensive mining (1850-1960) and 3) an industrial period (1966-1985), affected by the dumping of highly polluting waste into this estuary.

Carnets Geol., vol. 22, no. 19, p. 825-845

Online since December 25, 2022


Pliocene bivalves (Pteriomorphia) of Algiers Sahel (Algeria): Systematics and palaeoecology
Sabiha TALMAT, Madani BENYOUCEF, Bruno FERRÉ, Sabrina BOUZEGUELLA & Fatma-Zohra OUCHENE

 | HTML  | PDF [2,394 KB]  | DOI: 10.2110/carnets.2022.2218

 Abstract:  A hundred specimens of pteriomorph bivalves were collected from the marine deposits of the marly-sandy formations of Algiers Sahel, which correspond to transitional facies between the Piacenzian deep marly deposits and the Astian molassic deposits. They are herein analysed from a systematic, taphonomic, palaeoecological and paleoenvironmental point of view. The preliminary inventory list consists of 27 species belonging to eight families: Arcidae, Nuculidae, Glycymeridae, Spondylidae, Pectinidae, Plicatulidae, Gryphaeidae, and Ostreidae. Two sedimentary units with different bivalve biodiversity are recognized: the first: a shallow infralittoral unit characterised by large Flabellipecten alessii, Aequipecten angelonii, Ostrea lamellosa and O. edulis; the second: A deeper unit of circalittoral environment mainly includes Amusium cristatum. These bivalve shells display sclerobiont traces. Bioerosion traces are mostly assignable to clionid sponges (Entobia isp.), polychaete worms (Maeandropolydora isp. and Caulostrepsis isp.), bivalves (Gastrochaenolites isp.) and predatory gastropods (Oichnus isp.). Identified encrusting organisms are juvenile oyster shells, cirripedes, polychaete worms (serpulids), and indeterminate bryozoans. Analysis of boring and encrusting traces indicate a progressive environmental change from a relative high energy setting to a lower energy and deeper water setting, and correspond to a shallow sea with well-oxygenated waters.

Carnets Geol., vol. 22, no. 18, p. 795-824

Online since December 25, 2022


Calcareous nannofossils of the uppermost Bedoulian and lower Gargasian of La Tuilière - St-Saturnin-lès-Apt (area of the Aptian stratotype, Vaucluse, SE France)
Bernard C. LAMBERT

 | HTML  | PDF [3,071 KB]  | DOI: 10.2110/carnets.2022.2217

 Abstract:  An 148 m composite section located in the Gargas area stratotype in southeastern France has been studied for its calcareous nannofossil content. The four sections span the upper Bedoulian to lower Gargasian with the stadial boundary located within the basal section south of the village of Clavaillan. A total of 75 samples was processed to inventory taxonomy and stratigraphic distributions.
Eprolithus floralis is present at the base of the stratigraphic succession. The lowest occurrence of this species, which marks the base of Subzone NC7A, has been documented in the uppermost lower Aptian (Bedoulian) in other sections in southeastern France. The highest occurrence of the genus Micrantholithus has been utilized to delineate the base of Subzone NC7B. This subzonal boundary was placed at 48 m in the Les Gays I section (113.5 m in the composite) below the lowest occurrence of the foraminifer Globigerinelloides ferreolensis in the suprajacent sample (50 m). The lowest occurrence of Braarudosphaera africana is identified as a regional biohorizon in lower Subzone NC7A and a local proxy for the Bedoulian/Gargasian boundary. This event was placed at 15.5 m in the Clavaillan section at the base of the Dufrenoyia furcata Zone and within the "Niveau Blanc inférieur" marker bed (NB1).
The genus Nannoconus is abundant to very abundant in all samples examined. Taxonomic rigor has resulted in the recognition of five main morphologic groups (A-E), including all but one of the 15 species discriminated over this relatively short stratigraphic interval. Four main Nannoconus assemblage biozones - with one subdivision - have been distinguished through semi-quantitative analyses and organized relative to these taxonomic groupings. Assemblage Biozone B is restricted to the Bedoulian and has been correlated to the lower portion of Subzone NC7A (i.e., NC7A1). Assemblage biozones GI and GII (A-B) have been correlated to the upper portion of Subzone NC7A (i.e., NC7A2) and Biozone GIII to Subzone NC7B within the Gargasian.
Assipetra is another solution-resistant genus included in semi-quantitative analyses, where both its species were separated into small and large forms based on a size of 10 μm. The highest percentages of large morphotypes are within the Bedoulian in the lower 10.5 m of the Clavaillan section, roughly coeval to an acme of large Assipetra observed in the basal portion of the Serre Chaitieu section in the nearby Vocontian Basin.

Carnets Geol., vol. 22, no. 17, p. 745-793

Online since November 11, 2022


Palaeoentomological (fossil insects) outcrops in Lebanon
Sibelle MAKSOUD, Bruno R.C. GRANIER & Dany AZAR

 | HTML  | PDF [7,133 KB]  | DOI: 10.2110/carnets.2022.2216

 Abstract:  With 35 Cretaceous outcrops yielding fossil insects, either in amber or as rock (marls, limestones, cinerite, or dysodile) impressions-compressions (adpressions), Lebanon has continuously contributed significantly to the advance of palaeoentomology and to our understanding of entomological evolution and palaeobiodiversity. Compared to its small surface area, this country can be considered among the richest of fossil insect outcrops. This is due to its geological history and mainly to its forest, fluvial - lacustrine tropical and proximal marine subtropical palaeoenvironments plus Peritethys equatorial and subequatorial palaeogeography during the Lower and "Middle" Cretaceous. Herein, an exhaustive review of all outcrops with insects is given. A list of all fossil insects described from Lebanon is provided.

Carnets Geol., vol. 22, no. 16, p. 699-743

Online since September 14, 2022


A new discoid heliolitid (Proporidae) from the Upper Ordovician of the Baltic area: Morphology and modalities of increase
Yves PLUSQUELLEC, Jaap EYZENGA & Percy S.F. van KEULEN

 | HTML  | PDF [1,242 KB]  | DOI: 10.2110/carnets.2022.2215

 Abstract:   A species of Proporidae (Heliolitida) forming very small, discoid coralla, is fully described. It is mainly preserved in natural moulds in the Öjlemyr chert, an erratic silicified limestone found in Eridanos deposits surfacing in the west and north-east of the Dutch Overijssel-province and adjoining German area, generally accepted to be Uppermost Katian. The material is assigned to the rehabilitated Pinacopora Nicholson & Etheridge, 1878, a genus closely allied to Propora Milne-Edwards & Haime, 1849, and a new species, Pinacopora baltica is named. The main feature of this species, besides the characteristics of the genus and the biometric data, is the presence of wide, short, and convex septal ridges bearing scattered septal spines, alternating with narrow interseptal furrows. For the first time in heliolitids a pleurodictyoid pattern of growth is described. Only two species of Pinacopora are recorded: P. baltica n. sp. (Upper Ordovician) and P. grayi Nicholson & Etheridge, 1878 (Lower Silurian), respectively from Baltica and Laurentia.

Carnets Geol., vol. 22, no. 15, p. 685-698

Online since September 14, 2022


Nomenclatural Note, p. 684


Tethysian, Tethyan or ... Tethys Ocean and Tethys
Bruno GRANIER

 | HTML  | PDF [125 KB]  | DOI: 10.2110/carnets.2022.22EN1

 Abstract:  Tethys is a stand-alone modern noun, which does not require a qualifier in the English language. The use of the qualifiers Tethyan or Tethysian should be strongly discouraged. Taxa the names of which comprise the stem -tethy- are named after the Greek Goddess; those the names of which bear the stem -tethys- are named after the German (Suess, 1901), French (Suess, 1902) and English (Suess, 1908) Tethys Ocean. There was too much confusion on these two last points.

Thanks to our German-speaking readers (Olaf Elicki, Mike Reich, Torsten Scheyer, Ekbert Seibertz, ...) for having reported some grammatical errors: for instance, in the first table, one should read "(die) Tethys" instead of "(der) Tethys". [2022-08-12]

 
Carnets Geol., vol. 22, Editorial Note 1, p. 681-683

Online since August 10, 2022


The Lower Cretaceous Tuburan Limestone of Cebu Island, Philippines: Microfacies, micropalaeontology, biostratigraphy, and palaeogeographic perspectives
Jerali RODRIGO & Felix SCHLAGINTWEIT

 | HTML  | PDF [4,570 KB]  | DOI: 10.2110/carnets.2022.2214

 Abstract:  The occurrence of orbitolinid-bearing shallow water limestone blocks (Tuburan Limestone) incorporated into the volcanic series from Cebu Island, Central Philippines, has been known since the 1950's. Taxonomic studies including solid biostratigraphic data however are lacking or not substantiated. Herein we report the occurrence of Mesorbitolina texana (Roemer), transitional forms between M. texana and M. subconcava (Leymerie), Mesorbitolina birmanica (Sahni), Palaeodictyoconus actinostoma Arnaud-Vanneau & Schroeder, Neorbitolinopsis conica (Matsumaru), Paracoskinolina sp. and other benthic foraminifera (Akcaya, Praechrysalidina, Vercorsella) indicating a latest Aptian age. The previously accepted Late Albian age for the Tuburan Limestone based on Neorbitolinopsis conulus (Douvillé) is rejected herein and suggested as a misidentification with the recently revised Aptian - Lower Albian Neorbitolinopsis conica (Matsumaru). The general poverty of Lower Cretaceous dictyoconids in the Tuburan Limestone is interpreted as being caused by the lack of suitable extensive lagoonal facies that is generally typical for carbonate platforms of passive continental margins. The observed microfacies types instead refer to external platform margin settings with corals, stromatoporoids, sclerosponges (e.g., Acanthochaetetes), and planktic foraminifera. The recovered (micro) fauna from Cebu Island shows striking similarities to assemblages reported from Western and Mid-Pacific guyots but with indicated younger ages (up to the late Albian) based on data that - in our opinion - do not stand up to close scrutiny. Finally, a model is proposed interpreting the Tuburan Limestone from Cebu Island as remnants of a former carbonate cover of a guyot that originated as a volcanic island in the Western-Central Pacific, and later became incorporated into an accretionary wedge/mélange zone due to subduction-collisional processes.

Carnets Geol., vol. 22, no. 14, p. 631-679

Online since August 10, 2022


Tithonian-Hauterivian chronostratigraphy (latest Jurassic-Early Cretaceous), Mediterranean-Caucasian Subrealm and southern Andes: A stratigraphic experiment and Time Scale
Robert W. SCOTT

 | HTML  | PDF [1,106 KB]  | DOI: 10.2110/carnets.2022.2213

 Abstract:  New radioisotopic dates of Tithonian-Hauterivian strata in the Neuquén Basin significantly recalibrate Early Cretaceous numerical ages. In order to evaluate the implications of these revised ages, a graphic correlation experiment of twenty-three Andean Tithonian to Hauterivian sections integrated the ranges of 254 species, sequence boundaries, polarity chrons, and radioisotopic ages that compose the ANDESCS DB. This database accurately reproduces the order of Andean ammonite zones and places them in a relative metric scale of a composite reference section. The ranges in the ANDESCS DB were correlated with the LOK2016 DB that comprises Tithonian-Albian ammonites, calpionellids, nannofossils, and polarity chrons in Mediterranean-Caucasian Subrealm stage reference sections. In 2017 these ranges were calibrated to GTS2016 mega-annums (MA). Although most Andean ammonoids were endemic to the Indo-Pacific Subrealm, nannofossils, calpionellids and polarity chrons were present in both areas.
This stratigraphic experiment correlates base Berriasian as defined in France within the Substeueroceras koeneni Zone. In Andean sections this boundary is correlated with the Crassicolaria/Calpionella zone boundary dated at about 141 Ma. The base of the Valanginian defined by Calpionellites darderi correlates with the Neocomites wichmanni Zone of the Neuquén Basin (NB) recalibrated at 139.50 Ma, which is confirmed by multiple dates in Argentina, Mexico, Tibet, and elsewhere. The base Hauterivian correlates with base of Holcoptychites neuquensis Zone in the NB recalibrated at 131 Ma. Top of Hauterivian is in the Sabaudiella riverorum Zone in the NB and is dated at 127 Ma below an unconformity.
Previous cyclostratigraphic astrochronologic cycles are averaged and calibrate the duration of the Tithonian at 5.67 myr, the Berriasian at 5.27 myr, the Valanginian at 5.30 myr, and the Hauterivian at 5.60 myr. The age of each stage is recalibrated by adding revised durations to the most common age of base Valanginian of 139.5 Ma. These ages revise the Berriasian to Hauterivian stages time scale, and the ages of stage boundaries are on average 2.8 myr longer than proposed by the new Neuquén Basin radioisotopic dates.

Carnets Geol., vol. 22, no. 13, p. 619-660

Online since August 1, 2022


Priabonian non-geniculate coralline algae from the Central Carpathian Paleogene Basin
Juraj HRABOVSKÝ & Dušan STAREK

 | HTML  | PDF [8,002 KB]  | DOI: 10.2110/carnets.2022.2212

 Abstract:  Encrusting coralline algae are important rock-building organisms of the lower Priabonian limestones from the Central Carpathian Paleogene Basin. Despite the effort of early palaeontologists, former classifications lacked many diagnostic characteristics and modern taxonomic concepts, which hinders their use for modern palaeontological interpretations. The situation is further complicated as recent DNA analyses of extant coralline algae highlight the limits of the morpho-anatomical classification and identify many coralline algal genera which can also be recognized in the fossil record. Because palaeontology deals exclusively with the morpho-anatomical characteristics, a synthesis of the new discoveries in molecular phylogenetic analyses with morphology-based palaeontological classifications is necessary. Our palaeontological study based on published investigations on coralline molecular genetics enabled: 1) the identification of seventeen coralline algal morphological species grouped in six genera: Sporolithon lugeonii, Sporolithon nummuliticum, Sporolithon sp. 1, Sporolithon sp. 2, Lithothamnion camarasae, Lithothamnion cf. corallioides, Lithothamnion prascoi, Lithothamnion cf. ramosissimum, Lithothamnion roveretoi, Lithothamnion sp., Phymatolithon sp., Mesophyllum fructiferum, Mesophyllum cf. engelhartii, Mesophyllum sp., Chamberlainium lemoinei, Lithoporella melobesioides, and Lithoporella cf. minus ; 2) the description of Chamberlainium lemoinei (Miranda) comb. nov. known from the Bartonian, and 3) the identification of a unique encrusting coralline alga tentatively assigned to the genus Lithothamnion.

Carnets Geol., vol. 22, no. 12, p. 567-617

Online since August 1, 2022


A larger benthic foraminiferal zonation for the Eocene of the Caribbean and central American region
Simon F. MITCHELL, Edward ROBINSON, Ercan ÖZCAN, Mark M. JIANG & Natalie ROBINSON

 | HTML  | PDF [43,031 KB]  | DOI: 10.2110/carnets.2022.2211

 Abstract:  We have undertaken a study of the larger benthic foraminifera (LBF) of the Eocene of Jamaica that involved collecting free specimens and calibrating their occurrence against chronostratigraphy using calcareous nannofossils identified from sample splits or adjacent samples. The results have been plotted stratigraphically and allow a detailed zonation of the Eocene (14 zones) to be developed based largely on lepidocyclinids and similar forms. The zonation can be shown to be applicable to the Americas extending from northern South America, to Central America, the Caribbean and southern North America. The LBF biostratigraphy is based on the evolution of various groups. Three zones are recognized in the Ypresian, six zones in the Lutetian, three zones in the Bartonian, and two zones in the Priabonian. In order to classify the LBF we have revised the important groups used for the zonation scheme that occur in the Eocene and figure numerous examples. Our revision rearranges described genera into evolutionary, monophyletic clades to which we give the hierarchy of family and subfamily. We provide remarks on published taxa explaining how they are recognized and describe all the new taxa (two families, one subfamily, four genera and five species). The following families, genera and species are new: Butterliniana gen. nov., Helicosteginidae fam. nov., Helicostegina minor sp. nov., Helicostegina jamaicensis sp. nov., Helicostegina jeannemairae sp. nov., Pseudolepidinidae fam. nov., Orbitoininae subfam. nov., Planorbitoinella gen. nov., Polyorbitoinella gen. nov., Polyorbitoinella lilyfieldensis sp. nov., Orbitoina wrighti sp. nov., and Nephronummulites gen. nov.

Carnets Geol., vol. 22, no. 11, p. 409-565

Online since July 1, 2022


Nomenclatural Note, p. 566


Discussion of Laya et al. (2021), Dissolution of ooids in seawater-derived fluids - an example from Lower Permian re-sedimented carbonates, West Texas, USA [Sedimentology 68(6), 2671-2706]
Bruno R.C. GRANIER & Christopher G.St.C. KENDALL

 | HTML  | PDF [5,065 KB]  | DOI: 10.2110/carnets.2022.2210

 Abstract:  This discussion reassesses earlier interpretations of calcareous turbidites from the subsurface Spraberry Formation of the Happy Field (Garza County, NW Texas). It is based on routine petrographic analyses with a standard microscope. The succession of diagenetic products in this deep water setting were a little initial cementation by low magnesian calcite (LMC) and then the partial or complete leaching of both aragonite and high magnesian calcite (HMC) allochems facilitated by the presence of a residual primary intergranular porosity. This contradicts Laya et al.'s (2021) claim that cementation left no residual intergranular porosity so further leaching of the ooids would not have been possible. Instead the study made for this discussion with the same thin sections found residual primary intergranular porosity remains as evidenced by some of their photomicrographs. Most thin sections with porous grainstones have 1) collapsed molds that exhibit evidence of little initial cementation and 2) measured permeability values that range from some mD to some tens of mD. Isopachous LMC cements occur in almost all thin sections lining the margins of most intergranular pores. As these cements do not fully fill the pores, there is permeable well-connected residual primary porosity with no significant LMC cement in the secondary moldic porosity. Compaction affects the allochems and, where these are partially leached, intergranular and moldic porosities. Dissolution of aragonite (a major component) and HMC (possibly a minor component) was probably not coeval. The order of paragenetic sequence of this discussion study was: 1) LMC cementation; 2) aragonite leaching facilitated by oxidation of the organic matter in the "biocrystals" of bioclasts and oolitic cortices; 3) compactional brecciation, which was first mechanical, and then chemical causing local collapse of the molds of some of the largest pores. It was governed by cementation initially in a shallow burial diagenetic setting and then leaching whereas chemical compaction marks a slightly deeper burial diagenetic setting. The final event was marked by oil migration into the Happy Field reservoirs, freezing the calcium carbonate diagenesis. The theory of Laya et al. (2021) of the leaching of ooids in directly "seawater-derived fluids" is unsupported by the paragenetic sequence described above.

Editorial notice:  
Following the reading of a paper authored by J.C. Laya et al. in the journal Sedimentology, the authors submitted on 02-Nov-2021 a first discussion manuscript based on analogues. On 09-Nov-2021, this first manuscript was returned with harsh comments from three editors and ascribed the label "Reject & Resubmit". On 07-Mar-2022, the first author (BRCG) received a parcel with 40 thin sections to examine over a two weeks period. He was charged significant import taxes for this "scientific material". On 14-May-2022, the authors submitted a new discussion manuscript based on that same material that was studied by J.C. Laya et al. On 07-Jun-2022 this second manuscript was ascribed the label "Immediate Reject" without having any preliminary editorial reading. In the meantime, a claimant allegedly accused the first author (BRCG) of "serious breaches in academic publishing ethics" because he posted some photomicrographs of the material on a social network. On 05-Apr-2022 and again on 18-May-2022, this claimant addressed complains to the " Université de Bretagne Occidentale", an action that may be characterised as slander or defamation. Note that the authors were kindly granted the written permission to publish this discussion paper and another paper by the legitimate owner of the Happy Spraberry field, which also owns all material derived from any of their materials (e.g., cores). It looks like there is no evidence that it was the case for the other parties.

Carnets Geol., vol. 22, no. 10, p. 395-408

Online since June 19, 2022


A rare ammonite assemblage in the Romaniceras ornatissimum Zone (Middle Turonian) from the Uchaux Massif, Vaucluse, France
Francis AMÉDRO, Cyril BAUDOUIN, Gérard DELANOY, Christian DEVALQUE & Francis ROBASZYNSKI

 | HTML  | PDF [8,119 KB]  | DOI: 10.2110/carnets.2022.2209

 Abstract:  The Uchaux Massif (Vaucluse, SE France) is one of the rare places in Europe where ammonites collecting can be led from a high middle Turonian through Late Turonian. That incited Alcide d'Orbigny in 1852 to quote Uchaux as "the French type of the Turonian stage" to complement the Saumur, Tourtenay, Montrichard and Tours localities mentionned in 1842 when the stage was created. In 2014, the monograph by Robaszynski et al. synthetized and actualized the informations available on the litho- and biostratigraphy of the Turonian from the Uchaux Massif. More recently, a new outcrop at Mondragon, in a place named Prés Morel, exposes the whole carbonate siltstones with Spongia of the Peyras Member (UL3). Were collected : Lewesiceras peramplum (Mantell, 1822), Romaniceras (Romaniceras) marigniacum Amédro & Châtelier, 2020, R. (Yubariceras) ornatissimum (Stoliczka, 1864), R. (Y.) kanei Jones, 1938, Collignoniceras woollgari regulare (Haas, 1946), C. carolinum (Orbigny, 1841), C. papale (Orbigny, 1841), C. turoniense (Orbigny, 1841) and a new species of Collignoniceras : C. rhodanicum Amédro, Baudouin & Delanoy sp. nov. This assemblage, unprecedented in the studied area, is characteristic of the Romaniceras ornatissimum Zone which is the third of the four ammonite zones of the middle Turonian (Tm 3). At the top of this third zone, the surprise was to find the Romaniceras marigniacum bio-horizon defined in 2020 in the southern part of the Paris Basin at the top of the Tuffeau de Bourré and at the base of the Tuffeau Jaune de Touraine. Moreover, we now think that the Peyras Member has to be fully assigned to the Romaniceras ornatissimum Zone. Lastly, the assemblage includes a rich population of Collignoniceras carolinum (24 specimens), the most important known to-day over the world. All these ammonites allow to know the spectrum of their morphological variations and show a dimorphism through the existence of micro- and macroconchs.

Carnets Geol., vol. 22, no. 9, p. 333-393

Online since July 1, 2022


The Kalkowsky Project - Chapter IV. Case study of the Happy Spraberry oil reservoirs in NW Texas (with a micropaleontologic and biostratigraphic supplement): Collapsed molds should not be treated as a category of distorted ooids
Bruno R.C. GRANIER, Christopher G.St.C. KENDALL & Daniel VACHARD

 | HTML  | PDF [6,180 KB]  | DOI: 10.2110/carnets.2022.2208

 Abstract:  The subsurface upper Spraberry Formation in NW Texas is dominantly composed of calcareous turbidites and debris-flows. The petrographic analysis of its porous grain-supported fabrics revealed the presence of controversial superimposed compaction fabrics, sometimes referred to as "distorted ooids". Based on the paragenetic sequence, it is demonstrated that these allochems were not distorted. In fact, the related zigzag and silcrow (§) patterns result from the collapse of molds, either oomolds or biomolds, in response to mechanical compaction of the fragile framework made up of isopachous Low-Mg Calcite cement surrounding these empty molds. As a side finding, this stratigraphic unit, which was said to be late Kungurian in age, is proved to be nearly 7 millions of year older.

Carnets Geol., vol. 22, no. 8, p. 311-332

Online since June 2, 2022


Taxonomy of the fossil calcareous algae: Revision of genera Physoporella Steinmann and Oligoporella Pia (Dasycladales)
Tonći GRGASOVIĆ

 | HTML  | PDF [31,142 KB]  | DOI: 10.2110/carnets.2022.2207

 Abstract:  The taxonomic classification and mutual distinction of the genera Physoporella Steinmann and Oligoporella Pia (Dasycladales, green algae) have proven problematic and that has impeded their use in stratigraphy and other studies. The presence of single whorls of piriform laterals in Physoporella and double whorls in Oligoporella is considered as the main characteristic that separates these genera. According to that, diagnoses of genera and all species and varieties are changed or supplemented, and detailed descriptions are given. For this purpose the type-material from Pia's collection was re-examined and its redocumentation and reinterpretation performed. Additional information was obtained from abundant material from Croatia (Ivanščica Mt, Medvednica Mt, Žumberak Mt, Lika, Dalmatia). Only a few taxa were examined based on literature data. For all species and varieties reconstructions are given. Taxa from the Permian of East Asia are only briefly described. Among the investigated taxa, some of them have a structure that significantly differs from that present in the type species of the genera Physoporella and Oligoporella. They are separated into two new genera Ardeiporella and Neophysoporella. The revised genera Physoporella and Oligoporella, together with the newly established ones, give a clearer picture of phylogenetic relations.

Carnets Geol., vol. 22, no. 7, p. 171-310

Online since June 4, 2022


The report of a rare deformed eagle ray (Myliobatiformes: Myliobatidae) tooth plate from the Neogene of Calvert Cliffs, Maryland, U.S.A.
Stephen J. GODFREY, David J. BOHASKA & John MAISEY

 | HTML  | PDF [937 KB]  | DOI: 10.2110/carnets.2022.2206

 Abstract:  An isolated and deformed lower tooth plate of an eagle ray (Aetomylaeus sp., Myliobatidae, Myliobatiformes) is reported herein from the Miocene deposits along Calvert Cliffs, Maryland, U.S.A. Deformed myliobatid tooth plates like this, either fossil or modern, are exceedingly rare. All medial teeth are deformed/skewed such that the right side of each tooth forms an angle of about 10 degrees to the transverse axis of the dental plate. The skewed abnormal form of the teeth in USNM PAL 726325 is not thought to be the result of modern or taphonomic deformation. Rather, the deformity exhibited by USNM PAL 726325 gives every indication that successive similarly deformed teeth came about as a result of a persistent anatomical deformity of the dental lamina. From the consistency in the deformed shape of each tooth, it would appear as though the dental lamina retained this anomalous shape at least throughout the time represented by the age of the tooth plate. If this interpretation is correct, the deformity was not fatal and did not significantly impair the functionality of the tooth pavement over a protracted part (or all) of the individual's life span.

Carnets Geol., vol. 22, no. 6, p. 161-169

Online since May 10, 2022


The Kalkowsky Project - Chapter III. Significance of primary radial fabrics associated with ancient partly leached or recrystallized calcareous ooids
Bruno R.C. GRANIER & Philippe LAPOINTE

 | HTML  | PDF [1,851 KB]  | DOI: 10.2110/carnets.2022.2205

 Abstract:  Calcitic ooids and bothryoids from the Yacoraite Formation in the provinces of Jujuy and Salta (Argentina) display radial fabrics pointing to their primarily high-Mg calcite (HMC) nature. The present publication documents some specimens that are partly or fully leached or recrystallized, which raises fundamental questions about the validity of some concepts, such as the very existence of the so-called "two-phase"/"bimineralic" ooids. It is assumed here that the organic content in the oolitic cortices (and, subsequently, its degree of oxidation) is the key to explaining some differential diagenetic alterations.

Carnets Geol., vol. 22, no. 5, p. 149-160

Online since March 4, 2022


Adult morphologies of Puzosia quenstedti (Parona & Bonarelli, 1897) (Ammonoidea, Desmoceratidae) in the Albian of the South-East of France. Taxonomic implications
Jean-Louis Latil LATIL, Gérard DELANOY & Pierre DELATTRE

 | HTML  | PDF [5,643 KB]  | DOI: 10.2110/carnets.2022.2204

 Abstract:  Several adult specimens belonging to the genus Puzosia Bayle, 1878, were collected in the Albian of Lieuche (Alpes-Maritimes, France). Comparison with material from the condensed Albian levels of La Balme de Rencurel (Isère, France), in particular those described and figured by Jacob (1908), has highlighted a morphological link between the adult forms from Lieuche and the incomplete specimens from the condensed levels of the Lower-Middle Albian of south-eastern France and to identify them as Puzosia quenstedti (Parona & Bonarelli, 1897). These new details on the ontogenetic development of this species also allow new perspectives in the taxonomic treatment of Albian Puzosia species. A modified diagnosis of Puzosia quenstedti is proposed.
The presence of Douvilleiceras sp. juv. aff. D. mammillatum (Schlotheim, 1813) in superimposed overlying levels allows assignation of a Lower Albian (Douvilleiceras mammillatum Superzone) to a basal Middle Albian age (Hoplites dentatus Zone).

Carnets Geol., vol. 22, no. 4, p. 119-147

Online since February 28, 2022


The Kalkowsky Project - Chapter II. Wobbly ooids in a stromatolite from the Yacoraite Formation (Argentina)
Bruno R.C. GRANIER & Philippe LAPOINTE

 | HTML  | PDF [1,375 KB]  | DOI: 10.2110/carnets.2022.2203

 Abstract:  Eccentric ooids are described from a brackish Maastrichtian paleolake in NW Argentina. The first report of such atypical coated grains was from marine Upper Jurassic strata in SE Poland. Because their growth pattern is not likely to be confused with that of other "eccentric" ooids, such as asymmetric ooids, hiatus ooids, half-moon ooids, or "broken" ooids, it is suggested here to name them "wobbly ooids".

Carnets Geol., vol. 22, no. 3, p. 111-117

Online since February 15, 2022


The genera Roloboceras Casey, 1954, and Megatyloceras Humphrey, 1949 (Ammonoidea, Ancyloceratina, Douvilleiceratidae), from the Lower Aptian of Ardèche (SE France) - Taxonomic and biostratigraphic implications
Gérard DELANOY, Cyril BAUDOUIN, Antoine PICTET, Josep MORENO-BEDMAR, Camille FRAU & Bertrand MATRION

 | HTML  | PDF [11,947 KB]  | DOI: 10.2110/carnets.2022.2202

 Abstract:  The Lower Aptian marine deposits from southern Ardèche (South-East of France) yield a rich ammonite fauna of the sub-family Roloboceratinae Casey, 1961, which dates the upper Deshayesites forbesi Zone (Roloboceras hambrovi Subzone pro parte ?). The systematic study of this Roloboceratinae fauna has improved our knowledge of Megatyloceras coronatum Rouchadzé, 1933, type species of Megatyloceras Humphrey, 1949, as well as a better understanding of the genus thanks to the examination of the species from the Anglo-Paris Basin. A new species, M. leteilensis sp. nov. is introduced, and a description of M. transiens Casey, 1961, provided, with clarifications on its possible stratigraphic position. This study also establishes that the "species" Megatyloceras ricordeanum (Orbigny, 1850) represents only a growth stage shared by several species of Megatyloceras which is doubtfully a true taxon and must, therefore, be considered as a nomen dubium. The hypothesis of sexual dimorphism in Roloboceras Casey, 1954, and Megatyloceras is advanced. The study of this Roloboceratinae fauna highlights their heterogeneous distribution throughout Lower Aptian deposits of Ardèche, showing a direct correlation with bathymetric range. The biostratigraphical distribution of both genera on the Languedoc platform shows that Roloboceras is present from the uppermost C2 segment to the C4 segment of the stable carbon-isotope record, while Megatyloceras is limited to the middle C4 segment up to the lowermost C6 segment. Both genera coexist during the C4 segment.

Carnets Geol., vol. 22, no. 2, p. 7-109

Online since February 17, 2022


Nomenclatural Note, p. 110


Comments on a small sabretooth cat in the Abismo Ponta de Flecha Cave, Vale do Ribeira, southeastern Brazil
Artur CHAHUD

 | HTML  | PDF [448 KB]  | DOI: 10.2110/carnets.2022.2201

 Abstract:  Vale do Ribeira, in southeastern Brazil, is known for its many caves that contain osteological material, including remains that have been referred to several extinct species. The sabertooth cat Smilodon populator was a large predator that inhabited South America during the Quaternary. A specimen that is represented in the Abismo Ponta de Flecha Cave by small forelimb bones (metacarpals and phalanges) is commented here. The metacarpals display morphological characteristics of S. populator, but are smaller than those of S. fatalis and larger than those of S. gracilis. This specimen is amongst the smallest ever found specimen of S. populator and is comparable in size to an adult lion.

Carnets Geol., vol. 22, no. 1, p. 1-6

Online since January 17, 2022


up2  

2021 (vol. 21)

A possible crawling paracomatulid crinoid from the Lower Jurassic of central Italy
Riccardo MANNI & Rolando DI NARDO

 | HTML  | PDF [725 KB]  | DOI: 10.2110/carnets.2021.2119

 Abstract:  A new paracomatulid crinoid, Tiburtocrinus toarcensis gen. et sp. nov., is described from the Lower Jurassic of Tivoli (central Apennines, Italy). This type of stemless crinoids has never previously been recorded in Italy, and this report bridges a significant gap. Morphofunctional analysis of the radial facets suggests that Tiburtocrinus toarcensis gen. et sp. nov. may have been a crawling paracomatulid, very different from other paracomatulids that probably swam.

Carnets Geol., vol. 21, no. 19, p. 523-532

Online since December 25, 2021


Nomenclatural Note, p. 234


Biostratigraphic distribution of orbitolinids in the ammonite biozones (Urgonian platform of southeastern France). Part 2: Barremian p.p.
Bruno GRANIER, Bernard CLAVEL, Robert BUSNARDO, Jean CHAROLLAIS, Pierre DESJACQUES & Didier BERT

 | HTML  | PDF [27,925 KB]  | DOI: 10.2110/carnets.2021.2118

 Abstract:   The biostratigraphic distribution of orbitolinids for the Barremian of SE France proposed hereafter is calibrated on the ammonite biozonation. This work is based on the study of eleven sections with orbitolinids associated to macrofossils (ammonites and/or echinids) significant in terms of biostratigraphy or overlain with levels bearing the above macrofossils.

Carnets Geol., vol. 21, no. 18, p. 399-521

Online since October 24, 2021


The ichnospecies Linichnus bromleyi on a Miocene baleen whale radius preserving multiple shark bite-shake traces suggests scavenging
Stephen J. GODFREY & Annie J. LOWRY

 | HTML  | PDF [508 KB]  | DOI: 10.2110/carnets.2021.2117

 Abstract:  An isolated Miocene baleen whale left radius was marked repeatedly by shark bite-shake traces. The radius probably derives from the Plum Point Member of the Calvert Formation, Calvert Cliffs, Calvert County, Maryland, U.S.A. At least three successive bite-shake traces marking the radius, made by multiple teeth, are attributed to the trace fossil Linichnus bromleyi. These bite-shake traces consisting of shallow, thin arching gouges on a radius, likely indicate scavenging rather than active predation. The most likely means of producing the bundle of L. bromleyi within each of the three sets of traces would be through repeated biting as the shark re-positioned the prey in its mouth or, perhaps, by a shark species with multiple functional teeth within its tooth row. If the bite traces were produced by a non-serrated tooth (as they appear to have been), then the most likely candidate would be Carcharodon hastalis.

Carnets Geol., vol. 21, no. 17, p. 391-398

Online since October 24, 2021


Corrigendum, p. 202: An error was made in the spelling of the family name of one of the artists who created Figure 2. The correct spelling of his family name is "Schumaker".


New genera and species of ostracods from the El Ma El Abiod Miocene Basin (Tébessa, NE Algeria)
Francesco SCIUTO & Abdelhakim BENKHEDDA

 | HTML  | PDF [10,561 KB]  | DOI: 10.2110/carnets.2021.2116

 Abstract:  Two new ostracod genera of the family Trachyleberididae Sylvester-Bradley, 1948, each based on a new species, are described and commented here. The specimens were collected in Tortonian sediments cropping out at El Hadjra Safra in the El Ma El Abiod basin (region of Tébessa, north-eastern Algeria).

Carnets Geol., vol. 21, no. 16, p. 383-390

Online since October 24, 2021


Nomenclatural Note, p. 180


The late Berriasian early evolutionary burst of the Orbitolinidae: New insights into taxonomy, origin, diversification and phylogeny of the family based on data from eastern Serbia
Felix SCHLAGINTWEIT & Ioan I. BUCUR

 | HTML  | PDF [3,583 KB]  | DOI: 10.2110/carnets.2021.2115

 Abstract:  New data from the Carpatho-Balkanides of eastern Serbia evidence the more or less near-simultaneous "explosive" first appearances of several genera of the Orbitolinidae in the late Berriasian. Most of the observed taxa were previously recorded from strata not older than the Late Hauterivian (= classical Urgonian of southeastern France), evidence that these ages refer to local first appearance data. The diversified assemblage from Serbia includes representatives of the subfamilies Dictyoconinae: genera Cribellopsis Arnaud-Vanneau, Montseciella Cherchi & Schroeder, Orbitolinopsis Henson, Urgonina Foury & Moullade, Valserina Schroeder & Conrad, Vanneauina Schlagintweit, and Dictyorbitolininae: genus Paracoskinolina Moullade. Representatives of the Orbitolininae (with complex embryo) have not been observed. They appeared later in the fossil record seemingly during the Late Hauterivian-early Barremian. All together 17 taxa are reported, of which three in open nomenclature. A new species is described as Cribellopsis sudari n. sp. The majority of the observed species display medium- to high-conical tests and a rather simple exoskeleton lacking horizontal partitions (rafters). The new data contradict a phylogenetic evolution of distinct genera displaying different internal test structures one after the other in time (= ancestor-descendant relationships) as postulated by some authors. The explosive radiation ("early burst") of the Orbitolinidae in the late Berriasian is accompanied by the first appearance date of several other large benthic foraminifera including mostly agglutinating (e.g., Ammocycloloculina, Choffatella, Drevennia, Eclusia, Moulladella, Pfenderina, Pseudotextulariella) but also complex porcelaneous taxa (Pavlovcevina) providing evidence for a bioevent in this time period that exceeds the number of taxa originating in the previous (Tithonian) and the following stage (Valanginian). The early evolutionary history of the Orbitolinidae can be considered a classical example of adaptive radiation within the clade's history.

Carnets Geol., vol. 21, no. 15, p. 343-382

Online since August 17, 2021


Nomenclatural Note, p. 136


Rudist bivalves (Hippuritoidea) from the Clifton Limestone (Lower Campanian) of western Jamaica and a reassessment of the genus Vaccinites in the Americas
Simon F. MITCHELL

 | HTML  | PDF [3,583 KB]  | DOI: 10.2110/carnets.2021.2114

 Abstract:  The lower Campanian (Upper Cretaceous) Clifton Limestone of Jamaica yields three species of hippuritid bivalve: Barrettia ruseae Chubb, Whitfieldiella luceae sp. nov. and Vaccinites vermunti Mac Gillavry, and the plagioptychid: Plagioptychus sp. The hippuritids are described in detail using statistics. Barrettia ruseae is demonstrated to be a more primitive species of Barrettia than B. monilifera Woodward or B. multilirata Whitfield, and the species Whitfieldiella luceae is shown to be a more primitive species of Whitfieldiella than W. gigas Chubb. The specimens of Vaccinites from the Clifton Limestone are compared with populations of Vaccinites from elsewhere in the Americas, and five species (probably representing a single evolutionary lineage) are recognized: V. alencasteri sp. nov. (?late Turonian-?Coniacian), V. martini Mac Gillavry (probably early to mid Santonian), V. macgillavryi Palmer (probably mid to late Santonian), V. vermunti Mac Gillavry (earliest Campanian), and V. temazcali sp. nov. (late early Campanian). The Vaccinites species can be distinguished using statistical techniques. The ages of the Clifton Limestone and the five Vaccinites species are reviewed. This research demonstrates the value of using hippuritids for biostratigraphy in the Upper Cretaceous of the Americas.

Carnets Geol., vol. 21, no. 14, p. 315-341

Online since July 7, 2021


Nomenclatural Note, p. 342


Kimmeridgian and early Tithonian cephalopods from the Kisújbánya Limestone Formation, Zengővárkony (Mecsek Mountains, southern Hungary), their faunal composition, palaeobiogeographic affinities, and taphonomic character
László BUJTOR, Richárd ALBRECHT, Csaba FARKAS, Bertalan MAKÓ, Dávid MARÓTI & Ákos MIKLÓSY

 | HTML  | PDF [3,000 KB]  | DOI: 10.2110/carnets.2021.2113

 Abstract:  A new collection at Zengővárkony (Mecsek Mountains, Hungary) provided a rich and diverse but poorly preserved cephalopod-dominated fossil assemblage representing the Kimmeridgian and the lower Tithonian. The material came from mixed scree, soil, and amongst roots affected by weathering processes having been exposed to the elements for a long time. The nautiloid Pseudaganides strambergensis is the first record from the Mecsek Mountains. Due to the weathering, the ammonite fauna consists of mainly fragmentary and dissolved individuals that comprises 528 specimens belonging to 34 species and 30 genera out of which 20 species and 15 genera are reported for the first time from the Mecsek Mountains. The fauna includes specimens of known taxa. No new taxa are introduced. Based on the comparison with other faunas, this assemblage most closely resembles the fauna of the Venetian Alps (Italy). Additional faunal elements include aptychi (Laevaptychus latus, Lamellaptychus murocostatus), belemnites (Hibolithes semisulcatus), and an indetermined brachiopod. The first record of Spiraserpula spirolinites, an encrusting fossil polychaete preserved on the internal mould of a Taramelliceras shell fragment indicates favourable bottom conditions for the epifauna. The presence of Aspidoceras caletanum, Gravesia aff. gigas, and Pseudowaagenia inerme indicates faunal connections with the Submediterranean Province of the Tethys, which is in line with the tectonic and palaeogeographical position of the Mecsek Zone during the Late Jurassic. The ammonite assemblage represents elements of five Tethysian ammonite zones of the Kimmeridgian and Tithonian. The lower Kimmeridgian Herbichi Zone is indicated by Streblites tenuilobatus and Praesimoceras herbichi. The upper Kimmeridgian Acanthicum Zone is indicated by Aspidoceras acanthicum, and the Cavouri Zone by Mesosimoceras cavouri and Aspidoceras caletanum. The upper Kimmeridgian Beckeri Zone is suggested by Hybonoticeras pressulum and Pseudowaagenia inerme. Whereas Gravesia aff. gigas, Lithacoceras aff. siliceum, and Malagasites? denseplicatus are faunal elements characterising the Early Tithonian Hybonotum Zone. Phylloceratid and lytoceratid specimens account only for 12% of the fauna, while the majority of the specimens belong to the Oppeliidae and Ataxioceratidae (60%).

Carnets Geol., vol. 21, no. 13, p. 265-314

Online since July 4, 2021


The Cretaceous nautiloid genus Anglonautilus Spath, 1927, in France
Cyril BAUDOUIN, Gérard DELANOY, Jens LEHMANN, Camille FRAU, Roland GONNET & Jean VERMEULEN

 | HTML  | PDF [4,157 KB]  | DOI: 10.2110/carnets.2021.2112

 Abstract:  The occurrence of the nautiloid genus Anglonautilus Spath in France was limited to the report of Anglonautilus dorsoplicatus (Wiedmann) from the Albian of Escragnolles (Alpes-Maritimes) and Anglonautilus sp. from the Aptian of Les Ferres (Alpes-Maritimes). Here we document the presence of the successive species Anglonautilus praeundulatus Lehmann et al., Anglonautilus undulatus (Sowerby) and Anglonautilus dorsoplicatus (Wiedmann) from the Cretaceous of France. The stratigraphic range of Anglonautilus Spath, hitherto unknown before Aptian times is extended downward to the Hauterivian. The Hauterivian species Nautilus begudensis Kilian & Reboul, sometimes assigned to the genus Anglonautilus Spath, is revised and re-assigned to the genus Cymatoceras Hyatt.

Carnets Geol., vol. 21, no. 12, p. 235-263

Online since June 24, 2021


New insights into the depositional environment and stratigraphic position of the Gugu Breccia (Pădurea Craiului Mountains, Romania)
Traian SUCIU, George PLEŞ, Tudor TĂMAŞ, Ioan I. BUCUR, Emanoil SĂSĂRAN & Ioan COCIUBA

 | HTML  | PDF [3,293 KB]  | DOI: 10.2110/carnets.2021.2111

 Abstract:  The study of the carbonate clasts and matrix of a problematic sedimentary formation (the Gugu Breccia) from the Pădurea Craiului Mountains reveals new information concerning its depositional environment and stratigraphic position. The identified microfacies and micropaleontological assemblages demonstrate that all the sampled limestone clasts from the Gugu Breccia represent remnants of a fragmented Urgonian-type carbonate platform. The Barremian age of the clasts suggests that the stratigraphic position of the Gugu Breccia at its type locality could be uppermost Barremian-lowermost Aptian, a fact demonstrated also by the absence of elements from Lower Cretaceous carbonate platforms higher in the stratigraphic column (e.g., Aptian or Albian) of the Bihor Unit. The sedimentological observations together with the matrix mineralogy bring new arguments for the recognition of terrigenous input during the formation of the Gugu Breccia.

Carnets Geol., vol. 21, no. 11, p. 215-233

Online since June 24, 2021


Another thermophilic "Miocene survivor" from the Italian Pliocene: A geologically young occurrence of the pelagic eagle ray Aetobatus in the Euro-Mediterranean region
Alberto COLLARETA, Marco MERELLA, Simone CASATI, Giovanni COLETTI & Andrea DI CENCIO

 | HTML  | PDF [669 KB]  | DOI: 10.2110/carnets.2021.2110

 Abstract:  Aetobatus (Myliobatiformes: Aetobatidae) is a living genus of eagle rays that occurs in shallow-marine, tropical and subtropical environments of the Atlantic, Pacific, and Indian Oceans. Nowadays, Aetobatus does not inhabit the cool- to warm-temperate European and Mediterranean waters, though it is known from this broad region by virtue of several fossil teeth ranging chronostratigraphically from the lower Palaeogene to the upper Neogene. The present paper reports on a fossil aetobatid tooth discovered in mid-Pliocene (upper Zanclean to lower Piacenzian, 3.82-3.19 Ma) marine deposits exposed in the vicinities of Certaldo (Tuscany, Italy) and identified as belonging to †Aetobatus cf. cappettai. This specimen comprises the youngest occurrence of Aetobatus along the coasts of mainland Europe; furthermore, together with previous finds from roughly coeval deposits of Mallorca (Balearic Islands, Spain), it represents the most recent record of this genus in the whole Euro-Mediterranean region. In light of the environmental preferences of extant Aetobatus spp., our discovery suggests palaeoenvironmental conditions favourable to the persistence of tropical/subtropical taxa of "Miocene survivors" along the Pliocene coasts of Tuscany. In addition, it raises the question of whether or not the Messinian Salinity Crisis really resulted in the complete collapse of the Mediterranean marine biota and in the subsequent recolonisation of the Mediterranean Basin from the adjoining Atlantic waters and/or scattered marginal intrabasinal refugia at the beginning of the Pliocene. The possibility of Aetobatus recolonising the Mediterranean Sea through the Suez Canal in the near future is discussed.

Carnets Geol., vol. 21, no. 10, p. 203-214

Online since June 24, 2021


The Kalkowsky Project - Chapter I. Ooid - stromatoid relationship in a stromatolite from the Maiz Gordo Fm (Argentina)
Bruno R.C. GRANIER & Philippe LAPOINTE

 | HTML  | PDF [1,742 KB]  | DOI: 10.2110/carnets.2021.2109

 Abstract:  The comparative study of oolites and stromatolites demonstrates striking similarities between Kalkowsky's German Triassic material (drawn from the scientific literature) and our Argentinian Paleogene material. However, the latter better illustrates that ooids and stromatoids, hence oolites and stromatolites, which share the same dual (i.e., organic and mineral) nature, are merely the end-members of a continuum of microbial carbonate structures.

Carnets Geol., vol. 21, no. 9, p. 193-201

Online since June 14, 2021


Messinian ostracodes from the western Betic Strait (SW Spain)
Verónica ROMERO, Francisco RUIZ, María Luz GONZÁLEZ-REGALADO, Josep TOSQUELLA, Manuel ABAD, Tatiana IZQUIERDO, Antonio TOSCANO & Paula GÓMEZ

 | HTML  | PDF [620 KB]  | DOI: 10.2110/carnets.2021.2108

 Abstract:  During the Neogene, the Betic Strait was one of the gateways that connected the Atlantic Ocean and the Mediterranean Sea. In this paper, we have analyzed the ostracod faunas of samples collected from sediments crossed by a long borehole in southwestern Spain. These sediments were deposited in the Betic strait just before the Messinian Salinity Crisis. During the middle Messinian (6.8-6.0 Ma), the scarce and low diversified ostracod assemblages (Krithe, Parakrithe, Henryhowella) are typical of upper bathyal palaeoenvironments (200-400 m water depth). This period includes a short transition (6.26-6.25 Ma) to outer neritic palaeoenvironments, coinciding with a glaciation and characterized by the presence of Acanthocythereis hystrix (Reuss, 1850) and the disappearance of Krithe and Parakrithe. The most abundant species have a wide biostratigraphic distribution, most of them ranging from the Tortonian until the Holocene.

Carnets Geol., vol. 21, no. 8, p. 181-192

Online since April 1, 2021


Jurassian brachiopods of the Valanginian - Hauterivian interval. Their contribution to the dating of the Salima Formation in Mount Lebanon
Yves ALMÉRAS, Serge FERRY, Bruno R.C. GRANIER & Yann MERRAN

 | HTML  | PDF [1,734 KB]  | DOI: 10.2110/carnets.2021.2107

 Abstract:  The Jurassian French or Swiss outcrops of the lowermost Cretaceous (Valanginian or Hauterivian) yield numerous brachiopod species including 3 species: Lamellaerhynchia desori (Loriol in Pictet & Campiche, 1872), Sulcirhynchia valangiensis (Loriol, 1864), and Terebratulina arzierensis (Loriol, 1864), which are not found in Lebanon. The fossiliferous site of the Salima Formation at Zeghrine, a locality close to Bikfaya (Mount Lebanon), yields an assemblage made of Belothyris pseudojurensis (Leymerie, 1842), Lamellaerhynchia hauteriviensis Burri, 1953, Loriolithyris valdensis (Loriol, 1868), Lor. latifrons (Pictet, 1872), Sellithyris carteroniana (Orbigny, 1847), and Terebratulina biauriculata Orbigny, 1850; all are also present in Jurassian localities. On the basis of the study of its brachiopod assemblage, the Salima Formation is therefore ascribed an undifferentiated Valanginian age.

Carnets Geol., vol. 21, no. 7, p. 163-179

Online since March 24, 2021


First record of late Campanian paleoceanographic and paleoclimatic changes, Arabian Platform, Mazidag-Mardin area, SE Turkey
İsmail Ömer YILMAZ, Izzet HOŞGÖR, Sevinç ÖZKAN-ALTINER, Michael WAGREICH & Jiří KVAČEK

 | HTML  | PDF [1,897 KB]  | DOI: 10.2110/carnets.2021.2106

 Abstract:  The sedimentology, geochemistry and paleontology of the pelagic upper Campanian Maastrichtian Bozova Formation in the "Mazidag" (Mazıdağı) - Mardin area, SE Turkey, reveal paleoceanographic and paleoecological changes for the first time. A 119.25 m-thick composite stratigraphic section is characterized by alternating marls, clayey limestones, shales, and black shales; no coarse siliciclastic admixture or turbidite intercalations were recorded in the section. Biostratigraphic data indicate the presence of the Radotruncana calcarata Zone, and the UC15de/UC16 nannofossil zones. Stable isotope and elemental geochemical analyses have been carried out in the studied section. The isotope curves display similar patterns compared to reference curves from European and Chinese basins in the same interval. The prominent negative carbon isotope excursion determined in the upper interval can be correlated with the Late Campanian Event. Proxy elements display generally two relative rising trends in productivity from the lower part and the middle part of the succession. The lower part of the section records relatively more dysoxic/anoxic conditions and coincides with common black shale beds.
The presence of both diverse planktonic foraminifera and calcareous nannofossils in the studied interval indicates a fully marine, warm-water, low-latitude Tethysian oceanic environment. In addition, the plant fossils derived from the nearby land mass indicate that a tropical humid climate was similar to that in northeast Australia. Therefore, warm water, tropical humid atmospheric conditions developed in the studied area causing the rise in productivity, precipitation and transportation of plant debris into offshore environments.

Carnets Geol., vol. 21, no. 6, p. 137-162

Online since March 24, 2021


Bioerosion in Ostrea lamellosa shells from the Messinian of the Tafna basin (NW Algeria)
Mohammed N. NAIMI, Olev VINN & Amine CHERIF

 | HTML  | PDF [1,139 KB]  | DOI: 10.2110/carnets.2021.2105

 Abstract:  Bioerosional trace fossils (borings) are reported for the first time in Algeria. Three ichnotaxa observed in the shells of Ostrea lamellosa from the lower Messinian (upper Miocene) deposits of the Tafna basin (NW Algeria) are described. The ichnotaxa are Entobia cf. geometrica, Gastrochaenolites cf. torpedo and Trypanites isp.. Ostrea lamellosa shells are encrusted by balanid barnacles which are bored by Trypanites isp.. The ichnoassemblage is assigned to the Trypanites ichnofacies. Besides the bioerosion and encrustation described herein, specimens permitted the identification of the different phases of the Messinian transgression across the Souk el Khemis shoal.

Carnets Geol., vol. 21, no. 5, p. 127-135

Online since February 28, 2021


Mediterranean Neocomian belemnites, part 5: Valanginian temporal distribution and zonation (and some lithological remarks)
Nico M.M. JANSSEN

 | HTML  | PDF [5,238 KB]  | DOI: 10.2110/carnets.2021.2104

 Abstract:  A zonation based on the temporal distribution of belemnites is presented for the Valanginian and its boundaries. It is calibrated on ammonite controlled and bed-by-bed correlated sections from the pre-Vocontian Basin (southeast France). Three new sections are introduced herein that have previously not been investigated. All together, seven zones and six subzones are introduced. In addition, both within the Vocontian area, as well as outside (Bulgaria, Crimea, Czech Republic, France, Hungary, Morocco, Romania, Slovakia, Spain, Switzerland), differences regarding the spatial distribution of belemnites are investigated. Also, in two addenda, some remarks are given regarding lithological oddities.

Carnets Geol., vol. 21, no. 4, p. 67-126

Online since February 28, 2021


Revision of Ostrea (Gigantostrea) gigantica Solander var. oligoplana Sacco and Ostrea (Ostrea) isseli Rovereto (Oligocene, Tertiary Piedmont Basin, NW Italy)
Maria Cristina BONCI, Davide DAGNINO, Andrea MANDARINO, Aaron MAZZINI & Michele PIAZZA

 | HTML  | PDF [1,573 KB]  | DOI: 10.2110/carnets.2021.2103

 Abstract:  The aim of this paper is the revision and redocumentation of Ostrea (Gigantostrea) gigantica Solander var. oligoplana Sacco, 1897, Ostrea (Ostrea) isseli n. denom. Rovereto, 1897, and Ostrea (Ostrea) isseli n. denom. var. elongata Rovereto, 1897. These taxa are from the Oligocene strata of the Molare Formation (Tertiary Piedmont Basin, southern Piedmont - central Liguria, NW Italy). The syntypes of O. (G.) gigantica var. oligoplana are in the "Collezione Bellardi e Sacco", at the Museo Regionale di Scienze Naturali di Torino; the syntypes of O. (O.) isseli and O. (O.) isseli var. elongata are in the "Collezione BTP" (BTP Collection, at the Dipartimento di Scienze della Terra, dell'Ambiente e della Vita - DISTAV - of the Università di Genova). The var. oligoplana is here moved to the species rank and allocated to the genus Pycnodonte Fischer von Waldheim, 1835. O. (O.) isseli and O. (O.) isseli var. elongata are recognized as junior synonyms of the Sacco's taxon. Rovereto (1897) compared his new species with Ostrea subgigantea Raulin & Delbos, 1855, a poorly known taxon, that is here figured for the first time and shown to represent a species different from P. oligoplana (Sacco, 1897).

Carnets Geol., vol. 21, no. 3, p. 55-66

Online since February 24, 2021


Systematic revision and evolution of the Tithonian family Chitinoidellidae Trejo, 1975
Mohamed BENZAGGAGH

 | HTML  | PDF [1,884 KB]  | DOI: 10.2110/carnets.2021.2102

 Abstract:  Several new genera and species of the family Chitinoidellidae Trejo, 1975, were erected by Pop (1997, 1998a, 1998b). Some of these taxa are justified, but others are inadequately defined, and require revision. I discuss herein the non-validity of some taxa and propose a new systematic classification and an evolutionary framework for the family Chitinoidellidae, with two subfamilies: 1) Dobeninae, which include small-sized chitinoidellids, with the genera Borziella Pop, 1997, Carpathella Pop, 1998a, Daciella Pop, 1998a (amended), Dobenilla n. gen., and Popiella Reháková, 2002, and 2) Bonetinae, which includes larger-sized chitinoidellids, with the genera Bermudeziella n. gen., Bonetilla n. gen., and Furrazolaia n. gen.. These two families are separated in time. Small species of the subfamily Dobeninae characterise the Dobeni Subzone (Ponti ammonite Zone) and disappear immediately before the occurrence of the larger specimens of the subfamily Bonetinae, which characterise the Boneti Subzone (Microcanthum p.p. ammonite Zone).

Carnets Geol., vol. 21, no. 2, p. 27-53

Online since February 15, 2021


Nomenclatural Note, p. 54


Apianella nom. nov. (Dasycladales, Triploporellaceae): New name for the preoccupied algal genus Apinella Granier et al., 1986
Bruno GRANIER & François MICHAUD

 | PDF [123 KB]  | DOI: 10.2110/carnets.2021.21NN1

 
Carnets Geol., vol. 21, Nomenclatural Note 1, p. 26

Online since January 21, 2021


Bacinella, a discrete type of Mesozoic calcimicrobial structure
Bruno R.C. GRANIER

 | HTML  | PDF [3,800 KB]  | DOI: 10.2110/carnets.2021.2101

 Abstract:  The controversy surrounding Bacinella irregularis Radoičić, 1959, and Lithocodium aggregatum Elliott, 1956, has involved both sedimentologists and paleontologists. Arguments to exclude them from the Codiaceae are reviewed. The same arguments may be advanced to exclude their ascription to most other organisms. The only hypothesis resisting all elements of disproof is that of a consortium involving microbial communities. Accordingly, these structures are treated here as biosedimentary structures, namely bacinella structures, and not as taxa. One of the features specific to the organisms that built these structures is their strong corroding ability, as shown by the examples of fossils partly or fully cannibalized. This represents one state of corrosion beyond surficial etching and borings. Besides their capacity to corrode calcareous substrates, these microbial organisms formed nodules or oncoids and even built biostromes, which, depending on their stage of development, may have formed soft, firm or even hard substrates. However, to our knowledge, microbial communities contributing to bacinella structures never built up any bioherm. To complete this summary review, a building-block model that coherently takes into account most architectural variations is presented in the form of a figure sketch. The endolithic foraminifer Troglotella incrustans, which is commonly found associated with bacinella structures, is not an encruster or a borer. Lastly, contrary to certain erroneous hypotheses, no major bacinella episode has been ever found coeval with any significant Oceanic Anoxic Event.

Carnets Geol., vol. 21, no. 1, p. 1-25

Online since January 21, 2021


up2  

2020 (vol. 20)

The biosignature of sparite permits the distinction between gravitational cement and endostromatolites
Bruno R.C. GRANIER

 | HTML  | PDF [2,953 KB]  | DOI: 10.2110/carnets.2020.2020

 Abstract:  Following a brief summary of some fundamentals in carbonate sedimentology (sedimentary petrography) that highlights the significance of organic matter, some examples of biocrystals in carbonate grains/particles, such as bioclasts or ooids, are provided as an introductory chapter to a discussion on gravitational cements versus endostromatolites. The gravitational cements, either marine (fibrous) or continental (dog-tooth), are made of hyaline (i.e., translucent) sparitic crystals whereas endostromatolites are made of colored sparitic crystals and/or micrite. Gravitational cements forms in the vadose zone whereas endostromatolites grow in small rock cavities in the marine phreatic zone. As such the latter can grow centripetally in all directions (not only downward).

Carnets Geol., vol. 20, no. 20, p. 407-419

Online since November 20, 2020


The Mesozoic scleractinian genus Adelocoenia (Stylinidae) and its Jurassic species
Bernard LATHUILIÈRE , Rosemarie C. BARON-SZABO, Sylvain CHARBONNIER & Jean-Michel PACAUD

 | HTML  | PDF [4,677 KB]  | DOI: 10.2110/carnets.2020.2019

 Abstract:  The genus Adelocoenia Orbigny, 1849, is revised and a neotype is designated for its type species Astrea castellum Michelin, 1844. For various reasons that lie in the taxonomic history of scleractinian corals, it has become a difficult task to reliably assign Mesozoic corals having the combined features of plocoid corallite integration and the absence of a columella. Therefore, many such genera are in need of revision, one of which is Adelocoenia. In addition to the revision of the type species, Jurassic species grouped within Adelocoenia are revised using type material when it was possible. Many new synonymies are proposed based mainly on characters such as symmetry and dimensions of skeletal features. Another consequence is that most species previously grouped with Pseudocoenia Orbigny are transferred to Adelocoenia. Furthermore, we present a clarified view of the paleogeographical and stratigraphical distributional patterns of the genus Adelocoenia, according to which Adelocoenia had its first appearance during the Early Jurassic, represented by a single specimen known from the Sinemurian of France. Subsequently, this genus had a significant increase in both distribution and diversity during the Middle Jurassic. The pinnacle of its success followed in the Late Jurassic during which Adelocoenia had its greatest morphological disparity and taxonomical diversity, and its largest geographical distribution. The genus survived in the Cretaceous record. Throughout its history, Adelocoenia predominantly occurred in inner platform environments that were located in low latitudes.

Carnets Geol., vol. 20, no. 19, p. 367-406

Online since November 11, 2020


Exceptionally well-preserved silicified hippuritid rudist bivalves from the lower Maastrichtian of Puerto Rico
Simon F. MITCHELL

 | HTML  | PDF [5,339 KB]  | DOI: 10.2110/carnets.2020.2018

 Abstract:  Exceptionally well-preserved (silicified) hippuritid rudists occur in the El Rayo Formation (lower Maastrichtian) of south-western Puerto Rico. Three species belonging to three different genera are present: Caribbea muellerreidi (Vermunt), Laluzia peruviana (Gerth) and Parastroma guitarti (Palmer). Acid digestion of the limestones has resulted in a collection with numerous three-dimensional left and right valves many with the preservation of the minute details of the pore system. The morphological features of each species are described, and many features are illustrated for the first time. The new material, coupled with descriptions from other studies, demonstrates that six genera of endemic hippuritids evolved in two separate radiations in the New World: an older radiation of forms that had pallial canals in their left valves (Barrettia, Whitfieldiella and Parastroma) and a younger radiation of forms lacking pallial canals in their left valves (Laluzia, Caribbea and Praebarrettia). The exquisite preservation also reveals that in these endemic New World hippuritids the sockets for the teeth consisted of slots into which ribs on the teeth fitted; this contrasts with Old World hippuritids that have true sockets formed from upfolds of the tabulae for the teeth. The distinctive morphology of the tooth sockets is here used to define a monophyletic subfamily for which the name Barrettiinae Chubb is available.

Carnets Geol., vol. 20, no. 18, p. 333-366

Online since November 11, 2020


Messinian Lago-Mare ostracods from Tunisia
Rim TEMANI, Francesco SCIUTO & Hayet K. AMMAR

 | HTML  | PDF [1,121 KB]  | DOI: 10.2110/carnets.2020.2017

 Abstract:  Micropalaeontological analyses were performed on two stratigraphical sections sampled in upper Messinian deposits outcropping in eastern Tunisia, allowing us to identify some sedimentary levels with high concentrations of fresh or brackish water ostracods, which can be referred to the Lago-Mare fauna. Some of these species can be considered Paratethysian, or rather as species that spread in the Mediterranean area starting from the Paratethys areas, while others show Paratethysian affinity. The Lago-Mare fauna is little known in the south Mediterranean regions and the present article provides new data on its geographic distribution.
Of the two sections sampled, the first one, the Wadi El Kebir section, is located in the south eastern part of the Cape Bon Peninsula and shows horizons dominated by Cyprideis agrigentina and Cyprideis ex C. torosa group; the second one, the Salakta section, is located in the Sahel region and shows a level with a very rich Lago-Mare ostracod fauna consisting essentially of Amnicythere propinqua, Mediocytherideis punctata, and Ilyocypris gibba.

Carnets Geol., vol. 20, no. 17, p. 315-331

Online since October 14, 2020


First authentic record of the freshwater turtle Mauremys from the Upper Pliocene of Italy, with a new occurrence of the rarely reported ichnotaxon Thatchtelithichnus holmani
Alberto COLLARETA, Simone CASATI, Marco A.L. ZUFFI & Andrea DI CENCIO

 | HTML  | PDF [1,078 KB]  | DOI: 10.2110/carnets.2020.2016

 Abstract:  Nowadays, the living species of the terrapin genus Mauremys (Testudinoidea: Geoemydidae) are mostly found in eastern Asia, but three of them inhabit the Western Palearctic ecozone. In Italy, occurrences of living individuals of Mauremys are interpreted as records of alien species; however, a growing fossil record demonstrates that this genus has inhabited Italy as recently as the Late Pleistocene. We report on a new fossil specimen of Mauremys from the Upper Pliocene (Piacenzian) marginal-marine deposits of Tuscany (central Italy). This find, consisting of a partial plastron and a loose neural, represents the second authentic report of Mauremys from the Italian Pliocene, as well as the first one from the Piacenzian of Italy. Therefore, it is a significant fossil that fills a gap in the chronostratigraphic distribution of Italian fossil Mauremys, helping – together with the Lower Pliocene holotype of Mauremys portisi – to bridge the rich Miocene and Pleistocene segments of this record. Moreover, two unusual scars observed on the external surface of the studied plastron are here referred to the ichnospecies Thatchtelithichnus holmani. These traces represent one of the few records worldwide of this rarely identified ichnospecies, as well as its geologically youngest published occurrence. Hypotheses regarding the origin of the Thatchtelithichnus traces are reevaluated, and an origin as attachment scars of aquatic ectoparasites (possibly ticks, leeches, or flukes) is reaffirmed as probable in cases of traces occurring on the exterior of the plastral bones of turtles.

Carnets Geol., vol. 20, no. 16, p. 301-313

Online since October 14, 2020


Additional data on post-Paleozoic sea-lilies (Crinoidea, Echinodermata) from the Outer Carpathians of the Czech Republic and Poland
Mariusz A. SALAMON, Miroslav BUBÍK, Bruno FERRÉ, Andrzej SZYDŁO, Piotr NESCIERUK, Bartosz J. PŁACHNO, Tomasz BRACHANIEC & Karolina PASZCZA

 | HTML  | PDF [1,067 KB]  | DOI: 10.2110/carnets.2020.2015

 Abstract:  Jurassic (Tithonian) and Lower Cretaceous (Berriasian/Valanginian-Hauterivian) strata of the Vendryně and Cieszyn Limestones formations in the Czech Republic and Poland are locally rich in crinoid remains, consisting of whole cups, isolated cup elements, brachial plates, columnals and pluricolumnals, cirrals, and holdfasts. They are assigned to isocrinids (Isocrinida: Isocrinus cf. amblyscalaris, Isocrinida indet.), cyrtocrinids (Cyrtocrinida: Eugeniacrinites sp., Phyllocrinus sp., Gammarocrinites sp., Hemicrinus tithonicus, Plicatocrinus hexagonus, Cyrtocrinida indet.), millericrinids (Millericrinida: Millericrinida indet.), and thiolliericrinids (Comatulida, Thiolliericrinidae: Thiolliericrinidae gen. et sp. indet.). Late Cretaceous (Maastrichtian) and Paleogene (Paleocene-Oligocene) crinoids from the Subsilesian Unit are recorded as individual remains belonging to: Isocrinida indet., Cyrtocrinida indet., bourgueticrinids (Comatulida, Bourgueticrinina: Bourgueticrinina fam. et gen. indet.) and roveacrinids (Roveacrinida, Roveacrinidae gen. et sp. indet.). Roveacrinids were retrieved only from Maastrichtian samples. Despite the conclusions previously presented that isocrinids of the Outer Flysch Carpathians dominated around the Jurassic-Cretaceous boundary due to the very shallow sedimentary environment of these strata, we can now conclude that they were common and associated with cyrtocrinids in all types of environments. It is also worth mentioning that cyrtocrinids and isocrinids occur in Paleogene sediments that were deposited in extremely shallow environments. On the other hand, many literature data suggested that Cretaceous (by mid-Cretaceous) isocrinids migrated to deep-water areas, as a response to an increase in the number of predators during the so-called Mesozoic marine revolution.

Carnets Geol., vol. 20, no. 15, p. 283-299

Online since October 14, 2020


Lectotype designation for Orbitolinopsis flandrini Moullade, 1960 (Foraminifera): The missing piece of a taxonomic puzzle
Felix SCHLAGINTWEIT, Ioan I. BUCUR & François LE COZE

 | HTML  | PDF [1,370 KB]  | DOI: 10.2110/carnets.2020.2014

 Abstract:  Orbitolinopsis flandrini Moullade, 1960, was described from Lower Cretaceous Urgonian limestones of southeastern France without the designation of a holotype. It represents a valid taxon since the selection of a holotype is only obligatory for taxa established after 1999 (ICZN, 4th edition, article 72.3). Today the original description is considered to be a mixture of several taxa belonging to Orbitolinopsis Henson, 1948/Cribellopsis Arnaud-Vanneau, 1980 (transverse sections with cupules/septules in the central zone) and Drevennia Arnaud-Vanneau, 1980 (axial sections with an axial "columella-like" column). The short and in any case insufficient original description of O. flandrini, however, stressed the presence of a columellar-like central test as the main characteristic feature. In fact, the majority of the (sub)axial sections showing an axial column (lacking in Orbitolinopsis) are considered to belong to Drevennia (Family Pfenderinidae). Therefore, the new combination Drevennia flandrini (Moullade, 1960) is proposed and a lectotype herein designated from the original illustrations. Drevennia ecougensis, the type-species of the genus, is found to be a subjective junior synonym of the latter. New finds from Serbia and Spain extend the stratigraphic range of D. flandrini, from the upper Berriasian to the lowermost upper Aptian. The first occurrences of Drevennia, Dobrogelina Neagu, 1979, Pfenderina Henson, 1948, and Moulladella Bucur & Schlagintweit, 2018, in the upper Berriasian give evidence for an adaptive radiation of the Pfenderinidae during the time reported and from other, mostly complex larger benthic foraminifera (e.g., Orbitolinidae).

Carnets Geol., vol. 20, no. 14, p. 273-282

Online since September 21, 2020


Stratigraphic and taxonomic considerations on the Late Cretaceous rudist fauna of Aksai Chin (Western Tibet, China) from the De Filippi Collection
Jingeng SHA, Simone FABBI, Riccardo CESTARI & Lorenzo CONSORTI

 | HTML  | PDF [3,300 KB]  | DOI: 10.2110/carnets.2020.2013

 Abstract:  The rudist fauna collected in western Tibet in the Aksai Chin area by the De Filippi expedition in 1914 has been reprised and redescribed. This fauna is composed of Radiolites cf. lusitanicus, Radiolites sp., Gorjanovicia cf. endrissi, ? Sauvagesia sp., Sphaerulites sp., Durania sp., and Gyropleura sp. The rudist-bearing beds belong to the Tielongtan Group of the Tianshuihai terrane. The Turonian-? Coniacian Xiloqzung Formation (Fm.) bear the older rudists (Radiolites cf. lusitanicus, Radiolites sp., Sphaerulites sp., Durania sp.), whereas younger ages have been determined through microfossil analysis which, compared with the western Neotethys records, suggests an early-mid Campanian age. This allowed to ascribe the younger rudists of the collection (Gorjanovicia cf. endrissi, ? Sauvagesia sp., Gyropleura sp., Radiolites sp.) to the Dongloqzung Formation. Our data confirm that rudist-bearing facies in the Tielongtan Group extend at least up to the middle Campanian. The Aksai Chin rudist assemblage should belong to the Southwestern Asian assemblage of the Eastern Mediterranean Subprovince.

Carnets Geol., vol. 20, no. 13, p. 249-272

Online since September 21, 2020


Moldavite finds in Middle Miocene (Langhian Stage) deposits of southwestern Poland
Tomasz BRACHANIEC

 | HTML  | PDF [510 KB]  | DOI: 10.2110/carnets.2020.2012

 Abstract:  Most of the Ries tektites (moldavites) were deposited in sediments clearly postdating the Ries crater formation. This suggests secondary deposition for these ejected glasses. Only a few sedimentary formations known to contain these tektites are of Middle Miocene age and coeval with the Ries event. One is the Poznańska Formation, which is exposed across southwestern Poland. These mud deposits formed in the Middle Miocene (Langhian Stage). New moldavites, described in this report were found in the Poznańska Formation and weigh from 0.851 to 0.907 g. The North Stanisław sandpit, where the tektite specimens were found, is located 490 km from the Ries structure. These finds agree with the numerical simulation modelling of the ejection of these moldavites up to 600 km away from the source crater.

Carnets Geol., vol. 20, no. 12, p. 241-247

Online since June 30, 2020


Chamberlainium pentagonum (Conti) comb. nov. and Spongites fruticulosus (Corallinales, Rhodophyta) in the Miocene carbonates of the western Mediterranean
Giovanni COLETTI, Juraj HRABOVSKÝ & Daniela BASSO

 | HTML  | PDF [1,526 KB]  | DOI: 10.4267/2042/70837

 Abstract:  Molecular phylogenetic analyses discovered an unexpected biodiversity of coralline algae in modern oceans. This species richness is unlikely to be an exclusive characteristic of recent ecosystems. With the aim to investigate fossil coralline biodiversity, a large dataset of western Mediterranean Miocene specimens, previously identified as Spongites fruticulosus (and synonymized taxa), have been revised based on the current taxonomic framework. The analysis recognized two distinct groups. The first group includes the specimens fitting within the current description of S. fruticulosus. The second group consists of Chamberlainium pentagonum comb. nov., the first fossil representative of the genus. This species has been separated from S. fruticulosus on the basis of its smaller conceptacles and its thinner conceptacle roof. The very same characters have been highlighted by modern molecular phylogenetic analyses for separating Chamberlainium from Spongites. Chamberlainium pentagonum, similarly to the fossil specimens of Spongites fruticulosus, occurs in most of the investigated area and the two species coexist in several localities, indicating a similar and broad ecological tolerance for both taxa. These results suggest that Miocene coralline algal biodiversity is probably underestimated and prove the convenience of using large datasets for the study of fossil coralline algae.

Carnets Geol., vol. 20, no. 11, p. 223-240

Online since May 30, 2020


First occurrence of the problematic vetulicolian Skeemella clavula in the Cambrian Marjum Formation of Utah, USA
Julien KIMMIG, Wade W. LEIBACH & Bruce S. LIEBERMAN

 | HTML  | PDF [798 KB]  | DOI: 10.4267/2042/70836

 Abstract:  The Cambrian Marjum Formation of western Utah (USA) preserves a diverse soft-bodied fauna from the upper Drumian that is slightly younger than the well-known Burgess Shale. While the Marjum is dominated by arthropods, animals belonging to a variety of phyla have been found. Here, we document the second occurrence of the rare, enigmatic taxon Skeemella clavula, which was previously thought to be restricted to the Pierson Cove Formation of the Drum Mountains. The occurrence in the Marjum represents a new preservational setting, as well as a slightly younger deposit. The new specimens also expand the number of known specimens to three. In addition, they improve understanding of the morphology of this representative of the problematic phylum Vetulicolia.

Carnets Geol., vol. 20, no. 10, p. 215-221

Online since May 30, 2020


Metacuvillierinella sireli n. sp., a Campanian Rhapydioninidae (Foraminifera), from southeast Turkey. New considerations on the endoskeleton and particularities of the family, with a specialized lexicon
Jean-Jacques FLEURY & Recep ÖZKAN

 | HTML  | PDF [4,532 KB]  | DOI: 10.4267/2042/70793

 Abstract:  The family Rhapydioninidae is a part of the superfamily Alveolinacea. The main characteristic of this superfamily is its endoskeleton with each chamber divided into tubular chamberlets, fundamentally parallel to the coiling direction, and only connected in an undivided space located in the anterior part of the chamber: The preseptal space. The family Rhapydioninidae is distinguished by the coexistence of two sets of chamberlets: Primary chamberlets, which are isolated by partitions ("cloisonnettes"), forming a unique layer at the chamber periphery, and secondary chamberlets pierced in a more or less compact mass, the central endoskeleton (by no way homologous of the "couche basale", sometimes called flosculinisation or columella in some Alveolinidae). Two particular modes of organization of the secondary chamberlets occur, the Basal Secondary Chamberlets-Scattered Secondary Chamberlets structure (BSC-SSC) and the Confluent structure; they constitute supplementary features that distinguish this family from other groups.
The BSC-SSC structure (a new name for a previously well-known organization of chamberlets in the genus Pseudochubbina and Cuvillierinella salentina) is the object of a large inventory undertaken among the known taxa of the Rhapydioninidae. It leads to the observation that this particular endoskeleton is found in the various subfamilies on both sides of the Atlantic and cannot be used as a feature of taxonomic significance within the group. However, it is not observed in apparently "primitive" taxa equipped with chamberlets of large isodiametric diameter which display a "fishnet" appearance. The confluent structure is a new name for the helicoidal structure, which is also widespread within the family.
Metacuvillierinella sireli
n. sp., of Campanian age, is described from outcrop and subsurface limestones in southeast Anatolia, Turkey. The new taxon is a Rhapydioninidae based on its test architecture and endoskeleton. As a species, it is clearly distinct because of its initial planispiral coiling of A generation tests, its both pseudoplanispiral generations with an advolute final stage and its thin chamberlets showing an obvious BSC-SSC structure. The generic attribution appears more uncertain: The faint dimorphism between generations and the persisting pseudoplanispiral-advolute final stage are only known in the genus Metacuvillierinella. But M. decastroi, the type species, displays a small proloculus in the A forms, a miliolid juvenile stage, and an endoskeleton of "fishnet" appearance (cryptic BSC-SSC structure), which give it a particular character, appearing as being "primitive". This contrasts with the relatively large proloculus in the A forms, pseudoplanispiral coiling and the obvious BSC-SSC structure of the new taxon. Thus, all these features being subjected to evolution, the faint generational differences and the pseudoplanispiral-advolute coiling seem sufficient to suggest the affinities between the two taxa. The new taxon is, nevertheless, clearly more "advanced", which could be interpreted as a clue for a higher standing, possibly compatible with a new genus. This is not undertaken here, in consideration of the unknown "radiance" (small variations in several well-disseminated populations and/or other species of the same kind) of the new taxon with the present state of knowledge.
Additionally, with a review of the BSC-SSC structure, the various genera of the family Rhapydioninidae are revisited, namely Pseudochubbina, Cuvillierinella, Murciella, Sigalveolina, Cyclopseudedomia, Sellialveolina, Rhapydionina, Fanrhapydionina, Chubbina, Praechubbina, Raadshoovenia, Neomurciella, Twaraina; special attention is reserved to the Euro-Asiatic genus Pseudedomia, of which the original material and, consequently, the consecutive interpretative identifications, appear doubtful. New sections of Subalveolina dordonica and Fleuryana adriatica are figured.
The conclusion deals mainly with the criteria used for distinguishing various systematic levels within the family. The classical differentiation between "specific" and "generic" characters, if eventually convenient for simple or inadequately known groups, seems unsuited for a complex and well known family like this one. A more pragmatic mode of working is proposed, using any character as a simple element without any meaning by itself, but to be understood and interpreted among the others, that is to say in the evolutionary perspective of the whole group.
A lexicon of the used terms in Rhapydioninidae and closely related taxa in given in an appendix.

Carnets Geol., vol. 20, no. 9, p. 165-213

Online since May 11, 2020


Impact of the Anoxic Oceanic Event II on the evolution of ostracods in the Cenomanian-Turonian deposits of the Tinrhert Basin (SE Algeria)
Soumia TCHENAR, Bruno FERRÉ, Mohammed ADACI, Djamila ZAOUI, Madani BENYOUCEF, Mustapha BENSALAH & Touria KENTRI

 | HTML  | PDF [1,382 KB]  | DOI: 10.4267/2042/70792

 Abstract:  Around the Cenomanian/Turonian boundary in the Tinrhert Basin, ostracods are seldom found in most of the sampled levels. The assemblages show no specific diversity, their frequency not exceeding 4% of the whole microfauna. Their 'climactic' presence, both qualitatively and quantitatively, is observed at the base of the lower Turonian, where ostracod assemblages are dominated by the genera Cythereis, Paracypris, and Cytherella.
In order to interpret this data, we document a paleoecological study supported by evidence compiled from five geological sections, dealing with the respective impact of sedimentological conditions (quartz, gypsum and pyrite), and sea-level fluctuations.

Carnets Geol., vol. 20, no. 8, p. 145-164

Online since May 11, 2020


A report on the 12th International Symposium on Fossil Algae (Lucknow, India - September 16-18, 2019)
Daniela BASSO, Arindam CHAKRABORTY & Amit K. GHOSH

 | HTML  | PDF [2,175 KB]

Carnets Geol., vol. 20, Meeting Review 1, p. 141-144

Online since May 11, 2020


New occurrences of Modulidae (Mollusca: Gastropoda) from European Eocene, Oligocene and Miocene deposits: Data from 19th century collections
Pierre LOZOUET, Bruno CAHUZAC & Laurent CHARLES

 | HTML  | PDF [1,285 KB]  | DOI: 10.4267/2042/70761

 Abstract:  A re-examination of the historical collections deposited at the Bordeaux Museum of Natural History and the Faculty of Sciences of the University of Bordeaux made it possible to identify new taxa of Modulidae in the Oligocene and Miocene of the Aquitaine Basin. These Modulidae belong to the American groups Modulus modulus and Trochomodulus. In addition, three new species are described: Modulus benoisti sp. nov. (Serravallian), Trochomodulus stampinicus sp. nov. (Rupelian), which is close to Trochomodulus sublaevigatus (Orbigny, 1852), a Chattian species, and Incisilabium trochiformis sp. nov. (Priabonian). The latter is the oldest known Modulidae, together with Incisilabium parisiensis (Deshayes, 1832) (Middle Eocene) that was previously classified in the Trochidae. These results show that the paleobiogeography and origin of the family Modulidae need to be reconsidered.

Carnets Geol., vol. 20, no. 7, p. 125-139

Online since March 17, 2020


Full restoration of marine conditions after the late Messinian Mediterranean Lago-Mare phase in Licodia Eubea and Villafranca Tirrena areas (east Sicily)
Francesco SCIUTO & Angela BALDANZA

 | HTML  | PDF [691 KB]  | DOI: 10.4267/2042/70760

 Abstract:  After the Upper Messinian Mediterranean Lago-Mare phase, at the end of the Messinian salinity crisis, the Mediterranean basin was characterized by a return to normal marine conditions starting with the Lower Pliocene (Zanclean). In this period, remarkably thick layers of calcareous pelitic sediments, very rich in planktonic foraminifers and nannofossils, were widely deposited in the Mediterranean basin. The calcareous pelitic deposits of Sicily (Trubi Formation), as well as in other Mediterranean regions, were deposited conformably on the pre-Pliocene substrate, which is mainly represented by Messinian evaporites or by the post-evaporitic Lago-Mare facies. We have analysed samples taken from the lower portion of the Trubi Formation (Zanclean), just above the Messinian facies, collected from Licodia Eubea and Villafranca Tirrena areas (eastern Sicily). Micropalaentological assemblages consist of benthic and planktonic foraminifers and a typical deep-water ostracod fauna. The microfossil association and the stratigraphy of the Messinian-Pliocene transitional layers, supported by calcareous nannoplankton data, demonstrate not only rapid sea-level rise in this sector of the Mediterranean region, but also that this event, occurred without producing erosional features, unlike at other sites (e.g., Strait of Gibraltar).

Carnets Geol., vol. 20, no. 6, p. 107-123

Online since March 17, 2020


A rhinopristiform sawfish (genus Pristis) from the middle Eocene (Lutetian) of southern Peru and its regional implications
Alberto COLLARETA, Luz TEJADA-MEDINA, César CHACALTANA-BUDIEL, Walter LANDINI, Alí ALTAMIRANO-SIERRA, Mario URBINA-SCHMITT & Giovanni BIANUCCI

 | HTML  | PDF [1,180 KB]  | DOI: 10.4267/2042/70759

 Abstract:  Modern sawfishes (Rhinopristiformes: Pristidae) are circumglobally distributed in warm waters and are common in proximal marine and even freshwater habitats. The fossil record of modern pristid genera (i.e., Pristis and Anoxypristis) dates back to the early Eocene and is mostly represented by isolated rostral spines and oral teeth, with phosphatised rostra representing exceptional occurrences. Here, we report on a partial pristid rostrum, exhibiting several articulated rostral spines, from middle Eocene strata of the Paracas Formation (Yumaque Member) exposed in the southern Peruvian East Pisco Basin. This finely preserved specimen shows anatomical structures that are unlikely to leave a fossil record, e.g., the paracentral grooves that extend along the ventral surface of the rostrum. Based on the morphology of the rostral spines, this fossil sawfish is here identified as belonging to Pristis. To our knowledge, this discovery represents the geologically oldest known occurrence of Pristidae from the Pacific Coast of South America. Although the fossil record of pristids from the East Pisco Basin spans from the middle Eocene to the late Miocene, sawfishes are no longer present in the modern cool, upwelling-influenced coastal waters of southern Peru. Given the ecological preferences of the extant members of Pristis, the occurrence of this genus in the Paracas deposits suggests that middle Eocene nearshore waters in southern Peru were warmer than today. The eventual disappearance of pristids from the coastal waters off southern Peru might be interpreted as reflecting the late Cenozoic trend of strengthening of the Humboldt Current.

Carnets Geol., vol. 20, no. 5, p. 91-105

Online since March 17, 2020


Identification of a Romaniceras (Romaniceras) marigniacum sp. nov. ammonite biohorizon (Middle Turonian) at the base of the Tuffeau Jaune de Touraine (France)
Francis AMÉDRO, Francis ROBASZYNSKI, Hervé CHÂTELIER, Patrice FERCHAUD & Bertrand MATRION

 | HTML  | PDF [3,838 KB]  | DOI: 10.4267/2042/70720

 Abstract:   In the south of the Paris Basin, along the Loire and Cher valleys, the Tuffeau Jaune de Touraine Formation was traditionally attributed to the Late Turonian by the presence of rare Romaniceras deverianum (Orbigny, 1841). Moreover, the several metres of tempestites at the base of the formation never yielded ammonites. Today, in southern Touraine, more than 150 ammonites were collected from the base of the Tuffeau Jaune de Touraine and in the highest part of the underlying Tuffeau de Bourré bring new significant data: the lower part of the Tuffeau Jaune de Touraine remain in the Romaniceras ornatissimum zone, Middle Turonian in age (Tm 3). Furthermore, the discovery in that biohorizon of the new species Romaniceras (R.) marigniacum Amédro & Châtelier sp. nov. is indicative of the highest part of the R. ornatissimum zone (high Tm3). Other species are associated to the R. marigniacum biohorizon as: Romaniceras (Yubariceras) ornatissimum (Stoliczka, 1864), Masiaposites cf. kennedyi Amédro & Devalque, 2014, Collignoniceras woollgari regulare (Haas, 1946), C. turoniense (Sornay, 1951) and Collignoniceras vigennum Amédro & Châtelier sp. nov.
With regard to the top of the Tuffeau de Bourré Formation, it yielded about fifty specimens of ammonites but the assemblage is different to that found in the type locality of Bourré-Montrichard in the Cher valley. The material collected near the Vienne and Creuse junction includes : Lewesiceras peramplum (Mantell, 1822), Romaniceras (Y.) ornatissimum (Stoliczka, 1864), Collignoniceras woollgari regulare (Haas, 1946), C. canthus (Orbigny, 1856) and C. turoniense (Sornay, 1951). The species Collignoniceras papale (Orbigny, 1841), which represents one third of the Bourré collection is apparently absent whereas three new species belonging to the same genus are identified as : C. hourqueigi Amédro & Châtelier sp. nov., C. badilleti Amédro & Châtelier sp. nov. and Collignoniceras sp. A.

Carnets Geol., vol. 20, no. 4, p. 37-89

Online since February 22, 2020


A new Cassiduloid (Echinodermata, Echinoidea) in the Albian of the Sergipe-Alagoas basin, Brazil
Cynthia L. de C. MANSO

 | HTML  | PDF [410 KB]  | DOI: 10.4267/2042/70719

 Abstract:  This paper presents a new discovery of the echinoid species Phyllobrissus humilis (Gauthier, 1875) from the Albian age Riachuelo Formation of the Sergipe-Alagoas Basin. The only specimen obtained in the Maruim 1 outcrop expresses the main species characteristics. Paleoecological notes and a dichotomous key are presented to facilitate the identification of the cassiduloid species from the Cretaceous of Sergipe-Alagoas Basin.

Carnets Geol., vol. 20, no. 3, p. 29-35

Online since February 22, 2020


The shark-toothed dolphin Squalodon (Cetacea: Odontoceti) from the remarkable Montagna della Majella marine vertebrate assemblage (Bolognano Formation, central Italy)
Alberto COLLARETA, Andrea DI CENCIO, Renato RICCI & Giovanni BIANUCCI

 | HTML  | PDF [847 KB]  | DOI: 10.4267/2042/70716

 Abstract:  The extinct family Squalodontidae consists of heterodont, medium-sized odontocetes, featuring a long rostrum that houses large, procumbent incisors and heavily ornamented postcanine teeth carrying accessory denticles, hence their vernacular name, "shark-toothed dolphins". These longirostrine toothed whales are often seen as bridging the anatomical gap between archaic Oligocene odontocetes and their late Miocene to Holocene relatives. Possibly among the major marine predators of their time, the shark-toothed dolphins are important components of several lower Miocene marine-mammal assemblages from the North Atlantic and Mediterranean/Paratethysian realms. In the present work, a partial skull of Squalodontidae is described from the strata of the Bolognano Formation cropping out in the northeastern sector of the Montagna della Majella massif (Abruzzo, central Italy), which has previously yielded a rich lower Miocene marine-vertebrate assemblage, including eleven taxa of elasmobranchs as well as subordinate teleosts and very fragmentary remains of marine reptiles and mammals. The specimen consists of the anterodorsal portion of a rostrum, preserving parts of both premaxillae and left maxilla, and the anteriormost seven upper left teeth. This partial skull is here identified as belonging to the genus Squalodon, whose presence in the Montagna della Majella vertebrate assemblage had already been tentatively proposed on the basis of two fragmentary teeth. The paleontological significance of this find is discussed in the broader framework of the Euromediterranean record of Squalodon.

Carnets Geol., vol. 20, no. 2, p. 19-28

Online since February 22, 2020


A critical look at Tré Maroua (Le Saix, Hautes-Alpes, France), the Berriasian GSSP candidate section
Bruno R.C. GRANIER, Serge FERRY & Mohamed BENZAGGAGH

 | HTML  | PDF [2,966 KB]  | DOI: 10.4267/2042/70714

 Abstract:  The Tré Maroua site in SE France was recently selected by the Berriasian Working Group (BWG) of the International Subcommission on Cretaceous Stratigraphy (ISCS) as the candidate locality for the reference section of the Berriasian Global Boundary Stratotype Point (GSSP). However, on the basis of our preliminary investigation at this site and also from field observations over a larger area, this candidate section is paleogeographically located on a deep-water slope riddled with successive erosional surfaces, stratigraphic hiatuses and breccias. It does not meet at least four of the five "geological requirements for a GSSP". Accordingly, in our opinion, its candidacy must be definitely precluded.

Carnets Geol., vol. 20, no. 1, p. 1-17

Online since February 22, 2020


up2  

2019 (vol. 19)

Discussion on some previous records of Involutina hungarica (Sidó, 1952). Revision of the Jesse Harlan Johnson Collection. Part 6
Bruno GRANIER

 | HTML  | PDF [2,044 KB]  | DOI: 10.4267/2042/70638

 Abstract:  Involutina hungarica (Sidó, 1952) is reported from Albian strata of Texas (U.S.A.). Earlier records in the scientific literature, where this foraminifer commonly appears under the label "Hensonina lenticularis (Henson, 1947)", are reevaluated. Although it is mostly cited from Albian strata, its first occurrence could be Aptian.

Carnets Geol., vol. 19, no. 20, p. 445-455

Online since December 27, 2019


Ichnofossils associated with lingulide shells from the Lower Permian of Brazil
Olev VINN, Carolina ZABINI & Luiz Carlos C WEINSCHÜTZ

 | HTML  | PDF [840 KB]  | DOI: 10.4267/2042/70636

 Abstract:  Lingulides from Lower Permian of Brazil (24% substrates) showed signs of bioerosion in form of multiple small shallow pits that resemble incomplete Oichnus paraboloides borings. A single lingulide valve showed a centrally located large circular predatory Oichnus simplex boring. Several lingulide shells (c. 21%) show small Arachnostega traces in their interior. The diameter of Arachnostega burrows is relatively constant. These burrows are more similar to juvenile stages of Arachnostega gastrochaena and do not form well-developed meshwork of tunnels. This is the first record of Arachnostega from the interior of lingulide shells and indicates that even very small lingulide shells were suitable substrates for cryptic organisms.

Carnets Geol., vol. 19, no. 19, p. 439-444

Online since December 27, 2019


New data on the intergrowth of Rugosa-Bryozoa in the Lower Devonian of North Gondwana
Yves PLUSQUELLEC & Françoise P. BIGEY

 | HTML  | PDF [3,864 KB]  | DOI: 10.4267/2042/70538

 Abstract:  Numerous and generally well-preserved examples of the intergrowth Rugosa-Bryozoa from the Upper Pragian and Lower Emsian of the Armorican Massif (Châteaulin and Laval synclinoria), France, and from the Upper Emsian of the Ougarta Mountains, Erg Djemel, Algeria, are described. In the Armorican Massif, the corallites of a rugosan Tryplasmatidae? are intergrown with Ceramoporidae bryozoan close to Crepipora, exceptionally with an unidentified Fistuliporidae (likely a new genus), whereas in Ougarta the coral is not identifiable and is associated with a Fistuliporidae assigned to Fistulipora. Although mainly left in open nomenclature, the material is fully described (structure and microstructure) and illustrated (calcitic skeleton and natural moulds) for the first time. In addition, the presence of Ceramoporidae in the Lower Devonian is clearly established. The evaluation of the association is briefly discussed and a mutualistic relationship supported.

Carnets Geol., vol. 19, no. 18, p. 421-437

Online since November 11, 2019


The bryozoan collection of Prof. Dr Ehrhard Voigt (1905–2004) at the Senckenberg Institute in Frankfurt. Part 3 - Ascophoran Cheilostomata and bibliography
Silviu O. MARTHA, Kei MATSUYAMA, Joachim SCHOLZ, Paul D. TAYLOR & Gero HILLMER

 | HTML  | PDF [18,020 KB]  | DOI: 10.4267/2042/70501

 Abstract:  The bryozoan collection of Prof. Dr Ehrhard Voigt (1905–2004) at the Senckenberg Research Institute in Frankfurt am Main, Germany is a world-renowned collection of great scientific value. It is the world's largest collection of fossil bryozoans from the Upper Cretaceous and Paleocene and a unique archive documenting the evolution of this phylum of marine invertebrates during this time interval in the Boreal Chalk Sea that extended from the British Isles to the Aral Sea in Central Asia.
The Voigt Collection contains over 300,000 specimens and was relocated to the Senckenberg Institute in 2005 according to the bequest of Ehrhard Voigt. As a result of a DFG-funded project, we present here a three-part type catalogue of the holotypes and neotypes of 256 bryozoan species in the Voigt Collection, of which this is Part 3. In total over the three parts, 247 species are re-illustrated but the name-bearing type specimens of 20 species are missing and no material could be found for 9 species. Two species, described as ctenostome bryozoans by Ehrhard Voigt, are questionable, while a further three 'ctenostome' species and one 'ctenostome' genus are considered as ichnotaxa.

Carnets Geol., vol. 19, no. 17, p. 369-419

Online since October 10, 2019


Upper Jurassic-Lower Cretaceous limestones from the Hăghimaș Massif (Eastern Carpathians, Romania): Microfacies, microfossils and depositional environments
Olimpiu NEAMŢU, Ioan I. BUCUR, Răzvan UNGUREANU & Cristian Victor MIRCESCU

 | HTML  | PDF [4,430 KB]  | DOI: 10.4267/2042/70499
erratum PDF [119 KB]

 Abstract:  The Hăgimaş Massif provides important data for reconstructing the geological evolution of the Transylvanian Carbonate Platform. This unit is present nowadays in the basement of the Transylvanian Depression and as large-scale olistoliths, which crop out in various locations in the Eastern Carpathians and Apuseni Mountains. They contain a large variety of microfacies as well as microfossil assemblages partly encompassing the Jurassic/Cretaceous boundary. This study presents a detailed account of uppermost Jurassic-lowermost Cretaceous limestones from the Lapoş Valley (Hăghimaş Mountains) containing two distinct successions separated by a fault. The first succession contains platform margin and inner platform deposits (subtidal, intertidal) whereas the second one consists of inner platform deposits (shallow-subtidal to peritidal carbonates). The Upper Jurassic Stramberk-type facies is overlain by lower Berriasian regressive peritidal limestones. The upper Berriasian-? lower Valanginian consists mainly of inner platform deposits. They contain alternating, high and low-energy carbonates with rare calpionellids and calcispheres. The age assignment is based on a rich and diverse micropaleontological assemblage containing similar biota reported from other regions of the Tethysian Realm.

Carnets Geol., vol. 19, no. 16, p. 345-368

Online since October 10, 2019


The bryozoan collection of Prof. Dr Ehrhard Voigt (1905–2004) at the Senckenberg Institute in Frankfurt. Part 2 - Ctenostomata and non-ascophoran Cheilostomata
Silviu O. MARTHA, Kei MATSUYAMA, Joachim SCHOLZ, Paul D. TAYLOR & Gero HILLMER

 | HTML  | PDF [28,305 KB]  | DOI: 10.4267/2042/70498

 Abstract:  The bryozoan collection of Prof. Dr Ehrhard Voigt (1905–2004) at the Senckenberg Research Institute in Frankfurt am Main, Germany is a world-renowned collection of great scientific value. It is the world's largest collection of fossil bryozoans from the Upper Cretaceous and Paleocene and a unique archive documenting the evolution of this phylum of marine invertebrates during this time interval in the Boreal Chalk Sea that extended from the British Isles to the Aral Sea in Central Asia. The Voigt Collection contains over 300,000 specimens and was relocated to the Senckenberg Institute in 2005 according to the bequest of Ehrhard Voigt. As a result of a DFG-funded project, we present here a three-part type catalogue of the holotypes and neotypes of 256 bryozoan species in the Voigt Collection, of which this is Part 2. In total over the three parts, 247 species are re-illustrated but the name-bearing type specimens of 20 species are missing and no material could be found for 9 species. Two species, described as ctenostome bryozoans by Ehrhard Voigt, are questionable, while a further three 'ctenostome' species and one 'ctenostome' genus are considered as ichnotaxa.

Carnets Geol., vol. 19, no. 15, p. 287-344

Online since October 10, 2019


Historical review together with stratigraphical and taphonomical considerations on the upper Pleistocene deposit of Arenal de son Servera (Mallorca, Balearic Islands)
Rafel MATAMALES-ANDREU

 | HTML  | PDF [1,165 KB]  | DOI: 10.4267/2042/70497

 Abstract:  The upper Pleistocene deposit of Arenal de son Servera is reviewed using data from earlier works and new considerations based on its stratigraphy and taphonomical aspects of the fossils. In the present study, five different kinds of facies are identified: [1] palaeosols with pebbles from the Miocene basement, [2] aeolianites, [3] foreshore deposits with thermophilous molluscan fossil fauna, [4] palaeosols resulting from the pedogenesis of the beach units, and [5] bioclastic channelled deposits eroding the underlaying units. The detailed taphonomical analysis revealed that the fossils enclosed in these rocks remained on the sea bottom for a significant amount of time, but they were not bioeroded, perhaps because a submerged sand bar repeatedly buried and exhumed them. In addition, the fact that Persististrombus latus shells are in their position of maximum stability allows to infer that they were washed up on the shore during moderately energetic events, possibly comparable to present-day ordinary storms. These two last points could be of interest to the field of coastal management, as they provide insight on the scope of physical changes these systems could undergo in the present warming of the Mediterranean.

Carnets Geol., vol. 19, no. 14, p. 277-285

Online since October 10, 2019


The bryozoan collection of Prof. Dr Ehrhard Voigt (1905–2004) at the Senckenberg Institute in Frankfurt. Part 1 - Introduction and Cyclostomata
Silviu O. MARTHA, Kei MATSUYAMA, Joachim SCHOLZ, Paul D. TAYLOR & Gero HILLMER

 | HTML  | PDF [23,917 KB]  | DOI: 10.4267/2042/70493

 Abstract:  The bryozoan collection of Prof. Dr Ehrhard Voigt (1905–2004) at the Senckenberg Research Institute in Frankfurt am Main, Germany is a world-renowned collection of great scientific value. It is the world's largest collection of fossil bryozoans from the Upper Cretaceous and Paleocene and a unique archive documenting the evolution of this phylum of marine invertebrates during this time interval in the Boreal Chalk Sea that extended from the British Isles to the Aral Sea in Central Asia.
The Voigt Collection contains over 300,000 specimens and was relocated to the Senckenberg Institute in 2005 according to the bequest of Ehrhard Voigt. As a result of a DFG-funded project, we present here a three-part type catalogue of the holotypes and neotypes of 256 bryozoan species in the Voigt Collection, of which this is Part 1. In total over the three parts, 247 species are re-illustrated but the name-bearing type specimens of 20 species are missing and no material could be found for 9 species. Two species, described as ctenostome bryozoans by Ehrhard Voigt, are questionable, while a further three 'ctenostome' species and one 'ctenostome' genus are considered as ichnotaxa.

Carnets Geol., vol. 19, no. 13, p. 221-275

Online since October 10, 2019


A new prospect in crinoid (Crinoidea, Echinodermata) research: An example from the Lower Jurassic of Montenegro
Mariusz A. SALAMON

 | HTML  | PDF [935 KB]  | DOI: 10.4267/2042/70491

 Abstract:  Lower Jurassic (Hettangian-Pliensbachian) shallow-marine ooidal limestones of southern Montenegro contain a large number of isocrinid ossicles. They are assigned to the following taxa: Isocrinus psilonoti (Quenstedt), Isocrinus sp., and Pentacrinites cf. fossilis Blumenbach. The echinoderm assemblage also yields cyrtocrinid ossicles (Cotylederma sp., Cyrtocrinina indet.) and echinoid spines (only spotted in thin sections); however, these elements are rare. Given the fact that the recorded assemblage comes from a single locality, there is a growing need for further research that will require intense sampling to compile and complete the faunal list of crinoids and other echinoderm taxa.

Carnets Geol., vol. 19, no. 12, p. 211-220

Online since October 10, 2019


New findings of the genus Revalotrypa, the oldest bryozoan genus of Baltoscandia, in north-western Russia
Petr V. FEDOROV & Anna V. KOROMYSLOVA

 | HTML  | PDF [954 KB]  | DOI: 10.4267/2042/70296

 Abstract:  New findings of esthonioporate bryozoans of the species Revalotrypa cf. inopinata, representing one of the oldest bryozoans of Baltoscandia, are described from an outcrop located in Leningrad Oblast' (north-western Russia). The colonies of this species are very small and were extracted from limestone-cemented nodules found in glauconitic sandstones of the lower part of the Joa Member (Paroistodus proteus conodont zone, lowermost Floian, Lower Ordovician). Combined X-ray microtomography and the examination of traditional thin sections under a stereomicroscope and a light microscope were used to study the morphology of this species.

Carnets Geol., vol. 19, no. 11, p. 199-209

Online since August 8, 2019


Abundant occurrence of Aspidiscus cristatus (Lamarck, 1801) in the "Marnes de Smail" Formation from the Batna area (NE-Algeria): Index species for the Middle Cenomanian
Sihem SALMI-LAOUAR, Bruno FERRÉ & Riadh AOUISSI

 | HTML  | PDF [1,295 KB]  | DOI: 10.4267/2042/70294

 Abstract:  The Cenomanian marls of the Batna region (NE Algeria) display several fossiliferous beds with highly diversified fauna. Among the abundant and well-preserved fossils stands out Aspidiscus cristatus (Lamarck, 1801). This coral taxon is assigned to the Family Latomeandridae Alloiteau, 1952, due to the presence of pennulae and inner septal margins with slight perforations. In the studied sections Aspidiscus cristatus is found in beds ranging from the Cunningtoniceras inerme Zone to the Acanthoceras amphibolum Zone, with a relative abundance within the Acanthoceras cf. rhotomagense Zone. This species is subsequently a good marker for the Middle Cenomanian in the Batna district. We give herein a systematic and paleontological description and discuss the paleoenvironmental and paleogeographic framework of this taxon. Actually the outer morphology of its test, with convex outer surface and planar to concave inner surface, suggests an adaptation to mud-supported, low-energy marine environments with high sedimentary rate. The paleogeographic range of this taxon, with often larger-size specimens on the southern and eastern margins of the Tethysian Realm, than those on the northern margin, supports very peculiar thermal gradient and climactic zone, with relatively warmer waters on the southern Tethysian margin during the Cenomanian, favoring a more frequent and more effective bioerosion on fossil specimens from southern Tethysian areas than that affecting specimens from northern Tethysian areas.

Carnets Geol., vol. 19, no. 10, p. 185-197

Online since August 8, 2019


The lower Aptian ammonites of the Les Ferres Aptian Basin (Lower Cretaceous, Southeast of France). Part I: Introduction and biostratigraphy
Stéphane BERSAC & Didier BERT

 | HTML  | PDF [4,427 KB]  | DOI: 10.4267/2042/70292

 Abstract:  On the southern margin of the Vocontian Basin (SE France), for taphonomic reasons (fragmentation, reworking, pyritization), lower Aptian (Lower Cretaceous) deposits of the interval between the Deshayesites deshayesi and Dufrenoyia furcata zones are usually not suitable for studying the late ontogenetic developments of ammonites (fossil cephalopods). In the vicinity of the village of Les Ferres (Department of the Alpes-Maritimes, SE France), a relatively thick sedimentary succession with well-preserved ammonites, representative of the zones mentioned above, is found in a small basin called the "Les Ferres Aptian Basin" (LFAB). The 1262 ammonites collected or studied in situ are dated from the Deshayesites forbesi Zone through the top of the Dufrenoyia furcata Zone. This study presents the lithostratigraphy, biostratigraphy derived from these ammonites, and the respective range of these taxa. This is an introductory contribution to any future palaeontological study of the lower Aptian ammonites in the Les Ferres area. The lithologic unit overlying the Hauterivian-Aptian limestones is introduced herein as the Les Graous Formation. It is subdivided in three members, from bottom to top: 1) the Combe de Joinet Member, 2) the Pont de la Cerise Member, and 3) the Les Graous Member. In addition, two remarkable levels are identified: the Ammonitoceras level (outstandingly abundant) and the Toxoceratoides bed.

Carnets Geol., vol. 19, no. 9, p. 149-183

Online since August 8, 2019


The nomenclatural status of Palaeothrissum inaequilobum Blainville, 1818, P. parvum Blainville, 1818, and Aeduella blainvillei (Agassiz, 1833) (Actinopterygii, Aeduellidae)
Arnaud BRIGNON

 | HTML  | PDF [576 KB]  | DOI: 10.4267/2042/70290

 Abstract:  It is shown that the species names Palaeothrissum inaequilobum Blainville, 1818, and P. parvum Blainville, 1818, from the Lower Permian (Asselian) of Muse, near Autun (Saône-et-Loire department, France) are senior synonyms of the widely used species name, Aeduella blainvillei (Agassiz, 1833). In the interest of nomenclatural stability, conditions exist which allow reversal of precedence as stated in Article 23.9.1 of the International Code of Zoological Nomenclature. Thus the species name Aeduella blainvillei (Agassiz, 1833) is regarded as valid, qualifying as a nomen protectum, whereas Palaeothrissum inaequilobum Blainville, 1818, and P. parvum Blainville, 1818, are invalid, qualifying as nomina oblita. Some of the specimens from the type series upon which P. inaequilobum, P. parvum and Aeduella blainvillei were erected, are identified.

Carnets Geol., vol. 19, no. 8, p. 141-148

Online since August 8, 2019


Observations on some Actinoporellas (Chlorophyta, Polyphysaceae). Revision of the Jacques Emberger Collection. Part 1
Bruno GRANIER

 | HTML  | PDF [5,236 KB]  | DOI: 10.4267/2042/70196

 Abstract:  On the occasion of the inventory of the J. Emberger Collection, specimens from the "Lower Cretaceous" (Valanginian and Hauterivian) of Algeria, which are referable to the genus Actinoporella (Gümbel in Alth) and which were earlier identified to its type-species A. podolica (Alth) by Conrad et al., are re-examined. They correspond to two discrete species, one of which could be a junior synonym of A. podolica, a synonymy that remains pending because it would require a new sampling at the original locality in western Ukraine some 140 years after the original specimens, now lost, were collected. Regarding their age ascription, they are Tithonian and/or Berriasian in age, i.e., latest Jurassic (sensu Oppel) in age, not earliest Cretaceous. In addition to these two Actinoporellas, a third discrete species, initially described as Clypeina nigra (Conrad & Peybernès), but later referred to the genus Actinoporella, is revised. New data justify its re-ascription to the genus Bakalovaella Bucur. Finally, it is now confirmed that both the Polyphysaceae and the modern Dasycladaceae derive from the Diploporaceae either directly or indirectly through the ancestral Dasycladaceae.

Carnets Geol., vol. 19, no. 7, p. 113-139

Online since May 31, 2019


New data on some type-species of Maastrichtian-Paleocene Dasycladales (Green algae) from Iran. Part I. Pseudocymopolia Elliott, 1970
Koorosh RASHIDI & Felix SCHLAGINTWEIT

 | HTML  | PDF [2,525 KB]  | DOI: 10.4267/2042/70194

 Abstract:  Pseudocymopolia anadyomenea, the type-species of the genus, was described by Elliott (1959) from the Maastrichtian of Iraq. Besides the type-locality, it was also recorded from the upper Maastrichtian Tarbur Formation of Iran, from Afghanistan and Tibet. A rich but moderately preserved material is analyzed herein, evidencing the presence of two discrete species: P. anadyomenea and P. acuta n. sp. The new species is characterized by its thallus morphology displaying tapering, keeled segment margins. Besides the morphology, both are also distinguished by biometric parameters such as the outer diameter (D), inner diameter (d), and the d/D ratio. All other Lower Cretaceous species of Pseudocymopolia as well as the Maastrichtian P. anadyomenea have rounded segment margins. Both taxa from the Tarbur Formation occur in inner platform quiet water depositional settings whereas the Lower Cretaceous representatives typically characterize platform margin deposits.

Carnets Geol., vol. 19, no. 6, p. 97-111

Online since May 31, 2019


Upper Devonian Griottes Limestone in NW Sahara (Algeria): Facies, environments and geodynamic significance
Abdelkader ABBACHE, Abdelkader OUALI MEHADJI, Catherine CRÔNIER, Ahmed Hamza FELLAH, Ninon ALLAIRE & Claude MONNET

 | HTML  | PDF [3,405 KB]  | DOI: 10.4267/2042/70192

 Abstract:  On the NW margin of the Algerian Sahara in the Bechar (Ben-Zireg), Ougarta (Marhouma) and Gourara (Charouine) basins, the Upper Devonian "griottes" nodular limestone was deposited during the Frasnian and the Famennian. These alternating clayey-sand-limestone deposits are rich in ammonoids. These facies vary laterally and in thickness in these three areas. These facies variations are directly related to depositional environmental conditions (hydrodynamism, basin physiography, sedimentary gaps). In the three studied areas, the griotte facies were deposited on a deep seabed platform and in basins under tectono-eustatic control. In the Ben-Zireg area platform facies are throughout the studied stratigraphic interval. In the Marhouma area, the facies change through time first as distal ramp sedimentation (Frasnian Ia), then shifting to an apron slope sedimentation with allodapic facies (Famennian II, VI and V), and then in basinal settings (Famennian II and VI). Finally, at the end of the Famennian, the series ended with sandy-clay slope sedimentation (lower member of the Ouarourout sandstone), and next platform sedimentation (upper member of Ouarourout sandstone) topped by an emersion surface. In the Charouine area, basin clays (hemipelagites) dominate the facies. The presence of asphaltene impregnations in the griotte facies and in centimetric slabs to metric blocks of the facies posterior to nodular limestones implies the effects of early diagenesis. This process played an important role in the sulphate reduction and the anaerobic oxidation of methane (biogenic and / or thermal). The segregation of sedimentary areas with griotte facies seems to be influenced by basement fragmentation. Indeed, the griotte facies closely follow the Pan-African flexure. In Ougarta, the "South Ougartian" fault corresponds to the extension of the mega-lineament of Tibesti. The reactivation of Precambrian basement faults during the Late Devonian may have been responsible for the observed contrasting facies.

Carnets Geol., vol. 19, no. 5, p. 71-96

Online since May 31, 2019


New stratigraphic and genetic model for the dolomitic Cretaceous Pinda reservoirs in Angola. Part II - Compelling arguments against early dolomitization and early leaching
Bruno GRANIER

 | HTML  | PDF [3,099 KB]  | DOI: 10.4267/2042/69773

 Abstract:  This is the second contribution to the stratigraphic and genetic model of the Pinda Group. The mid-Cretaceous Pinda Group of the Congo basin in the northern Angolan offshore is a transgressive supersequence. Its lower part is made of Bufalo and Pacassa facies that correspond respectively to mixed and calcareous-dolomitic grain-dominated fabrics. Both facies were strongly diagenetically altered, mostly by dolomitic replacement and leaching. Contrary to opinions expressed by other authors that both styles of alteration are early diagenetic phenomena, there is substantial evidence for a burial origin with dolomitic replacement and leaching of calcite having started at depths not less than 150 m and 400 m, respectively.

Carnets Geol., vol. 19, no. 4, p. 47-70

Online since February 15, 2019


The "avatars" of Triloculina laevigata Orbigny, 1826, generic and specific attribution
Armelle POIGNANT

 | HTML  | PDF [1,280 KB]  | DOI: 10.4267/2042/69756

 Abstract:  The purpose of this study is to clarify the problem posed by Triloculina laevigata Orbigny, 1826, nom. nud., described and figured by Fornasini in 1905. An other species, also called Triloculina laevigata was created by Bornemann in 1855 and Orbigny's specific name became invalid. This invalidity was only recently assessed and numerous authors still use the original assignation. Consequently, it seems necessary to erect a new name. After listing the various names, revising the subgenus and genera attributed to Triloculina laevigata, and comparing fossil and recent specimens, the name: Affinetrina alcidi Lévy et al., 1992a, is confirmed.

Carnets Geol., vol. 19, no. 3, p. 35-46

Online since February 4, 2019


Uteria naghanensis n. sp. (Dasycladale) from the Upper Maastrichtian of Iran
Koorosh RASHIDI & Felix SCHLAGINTWEIT

 | HTML  | PDF [1,498 KB]  | DOI: 10.4267/2042/69755

 Abstract:  A new dasycladalean alga is described as Uteria naghanensis n. sp. from the late Maastrichtian Tarbur Formation of the Zagros Zone, SW Iran. It is a small to medium-sized, rather well calcified species with small articles each bearing one fertile ampulla, alternating with close-set verticils of numerous sterile laterals. Another characteristic is its comparably wide main axis. The genus Uteria Michelin was so far only known from the Paleogene (Danian-Lutetian). The discovery of U. naghanensis n. sp. in inner platform wackestone of the Tarbur Fm. documents the origination of the genus already in the uppermost Cretaceous within an area belonging to the Arabian Plate.

Carnets Geol., vol. 19, no. 2, p. 21-33

Online since February 3, 2019


Reinstatement of the genus Bakalovaella Bucur, 1993 (Dasycladeae, Dasycladaceae), and a description of its earliest Cretaceous representative
Bruno R.C. GRANIER & Ioan I. BUCUR

 | HTML  | PDF [3,082 KB]  | DOI: 10.4267/2042/69540

 Abstract:  A new Dasycladacean species found in Hauterivian strata in Aquitaine is described. It is ascribed to the genus Bakalovaella Bucur, 1993, which is reinstated here. From a phylogenetic point of view, based of the "lifting piston" model, this taxon should be part of a lineage derived from the Diploporaceae.

Carnets Geol., vol. 19, no. 1, p. 1-19

Online since January 17, 2019


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2018 (vol. 18)

The ammonoid fauna of the Prionocyclus germari Zone (upper Turonian, upper Cretaceous) from Rochefort-en-Valdaine (Drôme, France)
Cyril BAUDOUIN, Gérard DELANOY, Christina IFRIM & Josep A. MORENO-BEDMAR

 | HTML  | PDF [8,174 KB]  | DOI: 10.4267/2042/69401

 Abstract:  The late Turonian ammonoid fauna of Rochefort-en-Valdaine (Drôme, France) is herein described in detail and the intraspecific variability of Vocontiiceras vocontiense Diebold et al., 2018, is studied. The ammonoid assemblage (9 taxa identified) was deposited within the Prionocyclus germari Zone, which was defined in Germany, and is now also documented in southeastern France. Moreover, the co-occurrence of the heteromorph ammonoids Hyphantoceras (Hyphantoceras) flexuosum (Schlüter) and Hyphantoceras (Hyphantoceras) ernsti Wiese indicates the lower part of the Prionocyclus germari Zone.

Carnets Geol., vol. 18, no. 14, p. 313-351

Online since December 31, 2018


First description of rare Teichichnus burrows from carbonate rocks of the Lower Paleozoic of Estonia
Olev VINN & Ursula TOOM

 | HTML  | PDF [3,048 KB]  | DOI: 10.4267/2042/68550

 Abstract:  Teichichnus burrows occur in the Sandbian, Katian and Telychian of Estonia associated with carbonate rocks. It is possible that Teichichnus is more common in the Sandbian than in the Lower to Middle Ordovician and in the Silurian. Two ichnospecies, T. rectus and T. patens, have been identified from the Lower Paleozoic of Estonia. This is the first record of T. patens in the Ordovician of Baltica. Teichichnus in the Sandbian, Katian and Telychian of Estonia is restricted to the shallowest tier levels. The rarity of Teichichnus in the carbonate sequences of the Ordovician and Silurian of Estonia reflects little bathymetric variability and an extremely low sedimentation rate in the shallow epicontinental basin.

Carnets Geol., vol. 18, no. 13, p. 305-312

Online since September 21, 2018


The Oligocene mollusc types of Gaetano Rovereto from Santa Giustina and Sassello (NW Italy)
Maria Cristina BONCI, Gian Mario DABOVE & Michele PIAZZA

 | HTML  | PDF [2,074 KB]  | DOI: 10.4267/2042/68549

 Abstract:  The present paper examines the type specimens of the bivalve and gastropod taxa described by Gaetano Rovereto in the years 1897-1914 coming from the Oligocene rocks of Santa Giustina and Sassello areas (Molare Formation, Tertiary Piedmont Basin, Central Liguria, NW Italy). These taxa are part of the "Collezione BTP" (BTP Collection) housed at the Dipartimento di Scienze della Terra, dell'Ambiente e della Vita - DISTAV - of the Università di Genova. The collecting sites reported in the Rovereto's papers and indicated on labels have been reinvestigated in the field. 22 taxa (6 gastropods and 16 bivalves) are revised and re-documented; 6 have been recognized as younger synonyms of other species, the others are valid taxa. The majority of this fauna is restricted to the Oligocene time and to the Tertiary Piedmont Basin.

Carnets Geol., vol. 18, no. 12, p. 281-303

Online since September 21, 2018


Campanian-Maastrichtian Rhapydioninidae in the Mediterranean area: Genera Murciella, Sigalveolina n. gen., and Cyclopseudedomia
Jean-Jacques FLEURY

 | HTML  | PDF [9,301 KB]  | DOI: 10.4267/2042/68382

 Extended abstract:  This is the third and last part of a review of the Rhapydioninidae, benthic foraminifera that inhabited almost alone the most central areas of carbonate platforms of the Mediterranean realm. A global schematic table (Fig. 18 , in addition to Figs. 15-17) shows their regional development. The stratigraphic succession of this family seems to have been dominated by three periods of emersion (one being documented, the others only inferred) that limit the time distribution of most of these taxa. Thus it is doubtful that this distribution can be used with certainty in other areas; for example the mention of "Cuvillierinella? sp." (possibly a Metacuvillierinella?) in the Upper Maastrichtian of Iran is a hint of such a discrepancy (Schlagintweit & Rashidi, 2016).
Rhapydionininae and Pseudedomiinae subfamilies are summarily considered here, either because the facts have been established previously, or because the knowledge of them is still fragmentary. The Rhapydionininae subfamily, summarily depicted in Figure 18, is characterized mainly by its endoskeleton, lacking the confluent structure, with a wide peripheral zone and a very early unrolling trend (either cylindrical: Rhapydionina, with small proloculus, or flabelliform: Fanrhapydionina, with large proloculus). The milioline origin of this subfamily is indicated by species of the R. dercourti group, which are faintly streptospiral in the initial stages of both generations (Fleury, 2014). The Pseudedomiinae subfamily is not the subject of these studies, being essentially represented by taxa in more Eastern regions. Besides, nothing definite can be deduced from the minimal knowledge of the group (see review in Mavrikas et al., 1994), until the type of the type species is still poorly known.
Cuvillierinellinae subfamily (Fleury, 2016) is made up of six genera, including Cuvillierinella from which the others are clearly derived. But the origin of this genus remains uncertain. However, the presence of Pseudonummoloculina aff. kalantarii in our samples enables the consideration of what would be such an ancestor and how it could be named. We can try to imagine it from a simple principle and a few observations. The principle is the independence of evolutionary characters, commonly observed elsewhere in the family but quite obvious in the type population of Cuvillierinella salentina (see De Castro, 1988; Fleury, 2016), in which coexist the well-known type and specimens of overall same appearance, either streptospiral and devoid of partitions, or planispiral with a highly specialized endoskeleton. The observations are those that can be performed on species described by various authors under the name of Pseudonummoloculina. These organisms change from streptospiral to planispiral stage during their development. Some have a unique "notched" opening, others a double row of openings (and complex combinations of these two rather indistinct types) and some have no endoskeleton while others display rudimentary partitions. Varying combinations of these characters defy the conventional criteria of classification, each combination (changing during the ontogenetic development) being likely to justify a generic or specific status according to the arbitrary ordinary standards. These organisms are however in all cases isolated in time and most often deprived of clearly identifiable descendants (with the exception of P. pecheuxi Fourcade & Fleury, 2001, which is the origin of the species of Praechubbina genus). They probably do not constitute a unique group, but represent a step in an iterative evolution, leading members of a group of Miliolacea to the Alveolinacea, as Reichel (1936, 1937) and Pêcheux (2002) conceived it and as Fleury and Fourcade (1990) illustrated. We are thus led to apply the generic term Pseudonummoloculina to indicate a transitional state, that is to say an evolving stage. We are here confronted with the fundamental difficulty of adapting a nomenclature of creationistic essence to the perpetual reorganization of living organisms. It is therefore futile to characterize by terminology the temporary results; the term Pseudonummoloculina seems better to express a vague and essentially unstable notion related to the realities of evolution, ... at least as long as evolving networks of various known stages are not identified.
The five genera derived from Cuvillierinella have a wide range of morphology (Fleury, 2016, Fig. 13). Each genus is characterized by a dominant evolutionary trend, variously associated with secondary independent features.
Metacuvillierinella and Pseudochubbina genera are treated superficially in this text and are probably derived from Cuvillierinella or its supposed close ancestor. Metacuvillierinella is the closest, comparable in its young stage to typical streptospiral tests of C. salentina, comprising an early well developed wide meshed endoskeleton. It is distinguished by its adult advolute coiling without final uncoiling and its very low dimorphism of generations, restricted to the initial coiling. Pseudochubbina is linked to Cuvillierinella perisalentina, also hesitating on its coiling mode ("Slow Axial Rotation" in Fleury, 2016), and sharing the "Scattered Secondary Chamberlets" (Fleury, 2016), which are the only likely criteria for the origin of this genus.
Murciella, Sigalveolina n. gen. and Cyclopseudedomia, are reviewed here from the types and various new populations, which allows deepening and renewing of the knowledge of them. They are all fully planispirally coiled in the A generation and to varying degrees display an endoskeleton that previously was called "helicoidal structure", here renamed 'confluent structure'.
Murciella is very close to Cuvillierinella as evidenced by the coexistence of specimens having characteristics of both types in the population of the Cuvillierinella type species. The existence of populations including both Cuvillierinella and Murciella, without morphological intermediaries, as well as the existence of populations containing only one or the other of these taxa emphasizes their independence. The six various populations assigned to M. cuvillieri, known from Spain to the Eastern Mediterranean sea, are likely to belong to the same zone (CsB6a) and were never associated with species of the overlying zone. These populations constitute a homogeneous set close to that of C. salentina appearance, with a little wider range of the A proloculus and a finer endoskeletal mesh. Tests of the B generation in several populations suggest that the holotype of the type species represents this generation, which appears to be less influenced by uncoiling than C. salentina.
Sigalveolina n. gen. has been long confused with Murciella, too incompletely known to be distinguished before now. This new genus characterizes younger levels (zone CsB6b). This study shows that the high degree of confluent structure that gives its individuality coincides with a morphological diversity illustrated by four distinct species, including a new one, Sigalveolina reicheli. This new species probably corresponds to the mythical material, known as "Cosinella", formerly discovered by Schlumberger from the Italo-Slovenian border. A tests of the four species are larger in size than those of Murciella, at diameters of proloculus of the same order of magnitude; they are only rarely uncoiled, with the apparent exception of Sigalveolina reicheli n. sp., which adopts this trend only at a very late development stage. B tests also tend to be involute at a later stage, in contrast to the early uncoiling of previous and next genera.
Cyclopseudedomia is characterized by a very large A proloculus and an extremely reduced involute stage resulting in a longer uncoiled uniserial stage. This outstanding evolutionary trend is modulated in four species, including three already described and a new one, C. mavrikasi from the Italo-Slovenian border and Southern Italy. This trend is well marked in tests of both generations. In A tests, the involute part never exceeds 1.5 whorls around a large proloculus, and the uncoiled part is either cylindrical or flabelliform. B tests are mainly made of large evolute flabelliform flange, reaching a discoidal stage in the type species only; these flanges are always flat and increase in thickness very slightly towards the periphery.
Finally, it must be noted that data in Figure 18, reduced to the A tests, are imprecise inasmuch as the genera generally include the features of several species, which are distinguished by nuances affecting their characters, but also because the time span of the genera and the included species likely does not correspond to the entire period of time covered by the zone in which they are recognized. This means that Figure 18 represents a state of schematic knowledge that can be improved only by specific careful field studies.

Carnets Geol., vol. 18, no. 11, p. 233-280

Online since September 4, 2018


Variations in fluvial reworking of Polish moldavites induced by hydrogeological change
Tomasz BRACHANIEC

 | HTML  | PDF [1,056 KB]  | DOI: 10.4267/2042/68186

 Abstract:  Moldavites as ejecta glasses are fragile and transient: they are quickly abraded in fluvial conditions, this was confirmed by tumbling experiments. In the present study, multiple tumbling experiments were conducted to simulate the hydrogeological conditions of deposition of moldavites found in several different gravel pits. These experiments threw new light on the evolution of tektites during reworking. It appears that the original glass shape and mass as well as environmental conditions such as river velocity and the type of sediment with which they are associated are all important variables. However, the experiment did not simulate other significant variables, such as the variability of environmental energy. With given advantageous conditions, moldavite glasses could probably have withstood dozen kilometers of reworking, but this assertion is not sufficient to constrain the distance to their supply areas.

Carnets Geol., vol. 18, no. 10, p. 225-232

Online since July 27, 2018


Inventory of Georges Pissarro's fossil collection from the Lutetian (middle Eocene) of Cotentin (France) kept in the Science Museum of Laval (France)
Jérôme TRÉGUIER & Jean-Michel PACAUD

 | HTML  | PDF [669 KB]  | DOI: 10.4267/2042/68184

 Abstract:  One-hundred and fourteen samples from the Georges Pissarro's collection are kept in the Sciences Museum of Laval. Most of these represent the molluscan fauna from the Eocene of Cotentin (Hautteville-Bocage, Fresville and Gourbesville; France), Loire-Atlantique (Saffré, France) and Alabama (Monroe, U.S.). They were part of a bigger collection gathered by Maurice Cossmann and Georges Pissarro at the end of the XIXth and the beginning of the XXth centuries, then subsequently split in two parts. The first one, Cossmann's, was sent to the National Museum of Natural History in Paris. Like the Marin Defrance's collection from the Museum of Caen, the second part, Pissarro's, was considered lost, and then partially discovered in the Sciences Museum of Laval, giving it some scientific significance. These samples from Cotentin have been curated and the types and figured specimens found are illustrated herein.

Carnets Geol., vol. 18, no. 9, p. 205-223

Online since July 27, 2018


A palaeobiological window into the Lower Cretaceous Cupido Formation: Puerto México section, Nuevo Leon, Mexico
Felipe TORRES DE LA CRUZ, Elizabeth CHACÓN-BACA, Yesica Edith GÓMEZ-MANCHA & Tomás COSSÍO-TORRES

 | HTML  | PDF [1,860 KB]  | DOI: 10.4267/2042/68182

 Abstract:  A rich geobiological record of Cretaceous biotic and abiotic interactions around the proto-Gulf of Mexico has been preserved in the massive Cupido carbonate platform, i.e., in a sedimentary sequence that represents a depositional period of approximately 15 Myr. This work documents lateral facies variation on a dip slope reef from a new outcrop in the upper part of the Cupido Formation in the state of Nuevo Leon, Mexico. The measured transect is correlated with a stratigraphic column logged in a nearby section. The preserved fossil biota represents marginal reef facies dominated by abundant rudist shells such as Douvillelia skeltoni, Toucasia sp., Offneria sp., and Amphitrocoelus sp. associated with relatively large colonial corals (with diameters up to 25 cm) like Stelidioseris sp. and to a lesser extent, with stromatoporoids. Benthic foraminifers (miliolids and textularids) with associated dasycladalean algae such as Salpingorella sp. and Terquemella spp. dominate the microfossiliferous content in wackestones to packstones. This facies is overlain by a thin (15-30 cm) stromatolite horizon at the upper end of the measured section. This locality represents a new paleobiological and taphonomic window into one of the most extensive carbonate platform system developed along the margin of the Gulf of Mexico during the Cretaceous.

Carnets Geol., vol. 18, no. 8, p. 187-203

Online since July 21, 2018


Phanerozoic Brachiopod Genera of China, by Rong Jiayu (editor-in-chief), Jin Yugan, Shen Shuzhong and Zhan Renbin (eds.), 2017
Fernando ALVAREZ & John TALENT

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Carnets Geol., vol. 18, Book Review 1, p. 183-186

Online since July 19, 2018


Valanginian belemnites: New taxonomical and stratigraphical observations
Nico M.M. JANSSEN

 | HTML  | PDF [1,029 KB]  | DOI: 10.4267/2042/68153

 Abstract:  Six new Valanginian belemnite species (Duvalia crassa sp. nov., Duvalia elongata sp. nov., Duvalia kleini sp. nov., Duvalia superconstricta sp. nov., Castellanibelus vaubellensis sp. nov., and "Hibolithes" lebresensis sp. nov.) are described here and two species (Duvalia aff. elongata and "Hibolithes" aff. pistilliformis (Blainville, 1827)) are left in open nomenclature. They come from both the distal and proximal parts of the Vocontian Basin in south-east France and the Baetic Cordillera in south-east Spain. In addition lectotypes are selected for Castellanibelus orbignyanus (Duval-Jouve, 1841), Castellanibelus picteti (Mayer, 1866), and Duvalia lata (Blainville, 1827).

Carnets Geol., vol. 18, no. 7, p. 167-181

Online since July 7, 2018


Heteroceras gracile sp. nov., a new species of Heteroceras Orbigny, 1849, from the upper Barremian of Morteiron (Alpes de Haute-Provence, France)
Cyril BAUDOUIN, Gérard DELANOY, Grégoire BOURNAUD & Roland GONNET

 | HTML  | PDF [959 KB]  | DOI: 10.4267/2042/66955

 Abstract:  The species Heteroceras gracile sp. nov. is described; it is a small and slender species, with a small helix and hamuliniform morphology, previously considered as an atypical variant of Heteroceras baylei (Reynès, 1876). In southeast France, it is mainly known in the Morteiron section (Alpes de Haute-Provence, France), but the species is also present in Bulgaria and possibly in Japan.

Carnets Geol., vol. 18, no. 6, p. 155-165

Online since May 18, 2018


Is Strontium-isotope stratigraphy a reliable tool for dating shallow-marine platform carbonates at the Barremian-Aptian transition? Review of western Tethyan case studies
Camille FRAU, Jean-Pierre MASSE, Mukerrem FENERCI-MASSE, Anthony J.-B. TENDIL, Antoine PICTET & Cyprien LANTEAUME

 | HTML  | PDF [917 KB]  | DOI: 10.4267/2042/66931

 Abstract:  Strontium-isotope measurements on Lower Cretaceous marine rocks derive from belemnite material sampled in ammonite-constrained basinal successions. A group of values with a narrow range across the Barremian/Aptian boundary does not allow the separation of the uppermost Barremian (Martelites sarasini ammonite zone) from the lower Aptian pro parte (Deshayesites oglanlensis-D. forbesi ammonite zones). Growing numbers of studies applied Sr-Isotope Stratigraphy (SIS) on Barremian-Aptian shallow-marine sequences (Urgonian facies) in order to solve controversial results obtained by using different shallow-water biological time markers. Based on re-examination of case studies, we conclude that Sr-isotope values can neither be used to prove nor to disprove the location of the putative Barremian/Aptian boundary based on biostratigraphy. Pending more data available, SIS should be used with caution for dating ammonite-free carbonate sediments in the corresponding time interval.

Carnets Geol., vol. 18, no. 5, p. 139-154

Online since April 21, 2018


Rediscovery of the type locality of the Udoteacean alga Boueina hochstetteri Toula, 1884, in the Lower Cretaceous of Serbia
Ioan I. BUCUR, Milan N. SUDAR, Emanoil SĂSĂRAN, Divna JOVANOVIĆ, George PLEŞ & Svetlana POLAVDER

 | HTML  | PDF [2,652 KB]  | DOI: 10.4267/2042/66509

 Abstract:  Boueina hochstetteri Toula (type-species of the genus) was published by Toula (1884) in the 10th report of his travel through the Balkan region. He considered this species to be a problematic organism with uncertain systematic affiliation. Later, Steinmann (1901) assigned this fossil to the calcareous algae. Our own field work performed in the autumns of 2015 and 2016 in the Pirot area (SE Serbia) led to re-identification of the rich Boueina hochstetteri type level, close to the confluence of the Temska and Nišava Rivers, the type locality of Toula. The rich Boueina level is part of a succession of bioclastic limestones. The fragments of Boueina thalli are occasionally branched, a feature supporting the interpretation of Boueina as an inarticulate udoteacean alga with rare branching.

Carnets Geol., vol. 18, no. 4, p. 123-137

Online since April 12, 2018


Early Cenomanian coral faunas from Nea Nikopoli (Kozani, Greece; Cretaceous)
Hannes LÖSER, Thomas STEUBER & Christian LÖSER

 | HTML  | PDF [23,800 KB]  | DOI: 10.4267/2042/66094

 Abstract:  A Lower Cenomanian marine succession rich in corals is reported from the western margin of the Pelagonian zone in central Greece. The succession starts with a coarse conglomerate followed by sandstone, nodular limestone and massive limestone. Fifteen levels contain corals with the nodular limestone being the most species-rich. As a total, 78 species in 46 genera are described. They belong to 15 superfamilies. Three genera and four species are described as new. The new genera belong to the families Heterocoeniidae and Felixaraeidae, and the informal Plesiosmiliids. The record of six genera results in stratigraphical range extensions. The coral associations show more relationships to Lower than to Upper Cretaceous faunas. Thirty-nine genera already existed before the Cenomanian and 33 genera continued into the Middle Cenomanian, but only 19 genera persisted into the Turonian. The coral fauna has close palaeobiogeographic relationships with mainly Boreal or North Tethyan Cenomanian faunas such as those of the Aquitanian Basin, the Basque-Cantabrian Basin, or with faunas from the northern margin of the Rhenish Massif, but shares also species with the Upper Aptian to Lower Albian of the Bisbee Basin in North America and with faunas of the Lower to Middle Albian of the Northern Pyrenees.

Carnets Geol., vol. 18, no. 3, p. 23-121

Online since April 1, 2018


Fossil whale barnacles from the lower Pleistocene of Sicily shed light on the coeval Mediterranean cetacean fauna
Alberto COLLARETA, Gianni INSACCO, Agatino REITANO, Rita CATANZARITI, Mark BOSSELAERS, Marco MONTES & Giovanni BIANUCCI

 | HTML  | PDF [2,032 KB]  | DOI: 10.4267/2042/65747

 Abstract:  We report on three shells of whale barnacle (Cirripedia: Coronulidae) collected from Pleistocene shallow-marine deposits exposed at Cinisi (northwestern Sicily, southern Italy). These specimens are identified as belonging to the extinct species Coronula bifida Bronn, 1831. Calcareous nannoplankton analysis of the sediment hosting the coronulid remains places the time of deposition between 1.93 and 1.71 Ma (i.e., at the Gelasian-Calabrian transition), an interval during which another deposit rich in whale barnacles exposed in southeastern Apulia (southern Italy) formed. Since Coronula Lamarck, 1802, is currently found inhabiting the skin of humpback whales [Cetacea: Balaenopteridae: Megaptera novaeangliae (Borowski, 1781)], and considering that the detachment of extant coronulids from their hosts' skin has been mainly observed in occurrence of cetacean breeding/calving areas, the material here studied supports the existence of a baleen whale migration route between the central Mediterranean Sea (the putative reproductive ground) and the North Atlantic (the putative feeding ground) around 1.8 Ma, when several portions of present-day southern Italy were still submerged. The early Pleistocene utilization of the epeiric seas of southern Italy as breeding/calving areas by migrating mysticetes appears to be linked to the severe climatic degradation that has been recognized at the Gelasian-Calabrian transition and that is marked in the fossil record of the Mediterranean Basin by the appearance of "northern guests" such as Arctica islandica (Linnaeus, 1767) (Bivalvia: Veneroida). The subsequent abandonment of the Mediterranean Sea by most species of mysticetes is likely to have resulted from the progressive emergence of shallow-water coastal environments that occurred in Calabrian and Middle Pleistocene times.

Carnets Geol., vol. 18, no. 2, p. 9-22

Online since March 19, 2018


Hedbergella yezoana is a valid species name: Comments on the case 3620 and decision (opinion 2362) by the International Commission of Zoological Nomenclature
M. Dan GEORGESCU

 | HTML  | PDF [623 KB]  | DOI: 10.4267/2042/64918

 Abstract:  International Commission of Zoological Nomenclature decided in September 2015 on case 3620 submitted by A. Ando (United States National Museum, Smithsonian Institution, Washington, D.C.), which regards the status of the species Ticinella primula Luterbacher in Renz et al., 1963, and Hedbergella trocoidea yezoana Takayanagi & Iwamoto, 1962. Decision was to place the former on the Official List of Specific Names in Zoology and the latter on the Official Index of Rejected and Invalid Specific Names in Zoology (ICZN, 2015, p. 227). The scientific fundamentals in the presentation of case 3620 are weak and do not support such a decision by the International Commission. Moreover, they create a significant disturbance of nomenclatural stability in the Linnaean classification of the Cretaceous planktonic foraminifera.

Carnets Geol., vol. 18, no. 1, p. 1-7

Online since February 15, 2018


up2  

2017 (vol. 17)

Revision of the Juliette Pfender Collection. 3rd part. About some fossil green algae
Bruno GRANIER & Ioan I.BUCUR

 | HTML  | PDF [6,036 KB]  | DOI: 10.4267/2042/64293

 Abstract:  This work is a new but minor contribution to the récolement of Juliette Pfender's collection of fossil green algae. It aims to establish a partial inventory of the green algae studied by this female researcher mostly renowned for her studies on red algae. The poor preservation of some thin sections and the scarcity of whole specimens only rarely allow the identification of the taxa at the level below the genus.

Carnets Geol., vol. 17, no. 14, p. 251-269

Online since December 24, 2017


Additional contributions to the knowledge of the Taquaral Member, Irati Formation (Lower Permian, Paraná Basin): Taphonomy and paleoenvironmental implications
Artur CHAHUD

 | HTML  | PDF [2,725 KB]  | DOI: 10.4267/2042/64291

 Abstract:  The silty shale facies of the Taquaral Member (Irati Formation), which is one of the Permian units in the Brazilian Paraná Basin, is discussed here based on the taphonomy relevant to the paleoenvironmental interpretation. The fossils are crustaceans (Clarkecaris and other indeterminate forms), isolated teeth, scales and bones of Actinopterygii, "Palaeonisciformes", which are the most common vertebrate remains, and also frequent scales of Coelacanthiformes. The scales, teeth and disarticulated bones are found together in accumulations, which may be interpreted as coprolites. Many of the fossil crustaceans display characteristics of ecdysis.

Carnets Geol., vol. 17, no. 13, p. 243-250

Online since December 24, 2017


Cornulitids from the Upper Ordovician of northwestern Russia
Olev VINN & Anna MADISON

 | HTML  | PDF [958 KB]  | DOI: 10.4267/2042/64289

 Abstract:  Four cornulitid species occur in the Rakvere Regional Stage in NW Russia. The new species Conchicolites rossicus is here described; it is the earliest known Conchicolites from the Ordovician of Baltica. The new species has very small tubes with sharp, strong and regular annulations. The diversity of cornulitids in the Rakvere Regional Stage at the Pechurki quarry is usual for the Upper Ordovician of Baltica. The cornulitids of Pechurki quarry encrusted hard organic substrates in a mud bottom (clay and carbonate clay) environment. Cornulites sterlingensis occurs both in the Upper Ordovician of North America and Baltica, which suggest a short distance between these two paleocontinents and/or similar environmental conditions.

Carnets Geol., vol. 17, no. 12, p. 235-241

Online since December 24, 2017


Mecaster texanus (Echinoidea) from Turonian-Coniacian strata in the Sergipe-Alagoas Basin, Brazil
Cynthia L. de C. MANSO & Wagner SOUZA-LIMA

 | HTML  | PDF [1,325 KB]  | DOI: 10.4267/2042/64287

 Abstract:  The spatangoid echinoid Mecaster texanus (Roemer) was first described from the Austin Chalk in Texas (USA). In northeast Brazil, this species was recorded from the Upper Cretaceous (Turonian-Coniacian) Jandaíra Formation in the Potiguar Basin. Here we extend the palaeogeographical distribution of M. texanus southwards to the Sergipe-Alagoas Basin, where this species occurs in the Turonian-Coniacian Cotinguiba Formation. A key to identification of spatangoids from the Cretaceous-Cenozoic sequence at Sergipe-Alagoas is added and considerations about other spatangoid species from that basin are presented.

Carnets Geol., vol. 17, no. 11, p. 221-234

Online since December 24, 2017


Palynology and sedimentary environments of the Devonian from the Saida area (northwestern Algeria)
Mohammed BOUGARA, Philippe STEEMANS, Alain LE HÉRISSÉ & Frédéric BOULVAIN

 | HTML  | PDF [1,679 KB]  | DOI: 10.4267/2042/64285

 Abstract:  Palynological interpretations of both spores and acritarchs from the Devonian Tiffrit Formation located in Saïda (North-Western Algeria) support identical conclusions. Species of spores and acritarches that appear in the upper layers of the younger reference unit, named Boukourdène (BK1), are compatible with a Pragian-Emsian age, based especially on the presence of the miospores Dibolisporites wetteldorfensis, Dictyotriletes emsiensis, D. subgranifer, Verrucosisporites polygonalis, and the acritarchs Evittia crucistellata, E. spicifera, Fimbriaglomerella aulerca, Florisphaeridium toyetae, and Veryhachium aff. V. vandenbergheni.

On the basis of occurrences of microconglomeratic levels with elements of Silurian phtanites found along the sedimentary units of Tiffrit, we consider that Silurian sediments as well as Lower Devonian sediments have been reworked. We thus propose a Praguian-Emsian age for the Boukourdène units.

From a sedimentological point of view, the Devonian sedimentary units of the Tiffrit Massif are linked to a gravitational deposition controlled by sea level rise and significant subsidence. Facies seems to change along an East-West axis. The particle size, the nature of the facies, and their extreme variability over short distances indicate a slope apron environment of deposition. The lithological, sedimentological and environmental characteristics of the studied system are consistent with deposition in an active tectonic margin setting.

Carnets Geol., vol. 17, no. 10, p. 191-219

Online since December 24, 2017


GSSP proposal for the upper Aptian substage in the Apt Basin (Vaucluse, SE France): Synthesis of the stratigraphic data
Michel MOULLADE, Guy TRONCHETTI, Christine BALME, Yves DUTOUR, Pierre ROPOLO, Gregory PRICE, Mathieu MARTINEZ & Bruno GRANIER

 | HTML  | PDF [2,338 KB]  | DOI: 10.4267/2042/62954

 Abstract:  The synthesis of the stratigraphic data collected over more than a decade in the stratotypic area has made it possible to establish a composite section of the "Aptian marls" from the Grandis ammonite Subzone to the base of the Melchioris Zone, i.e., from the Schackoina (Leupoldina) gr. cabri foraminiferal Zone to the Globigerinelloides algerianus Zone. This composite section includes the partial sections from Clavaillan, South and East Pichouraz, La Tuilière, Les Gays and Gargas (Vaucluse, SE France). In particular, our revision has shown that the marly calcareous bed, which divides the marly series of Clavaillan and Pichouraz, compared with  the Vocontian "Niveau blanc" and thought to be unique and isochronous, corresponds in fact to two stratigraphically distinct levels.
The present study confirms that the visible series of marls in the stratotypic area, not taking into account the "A1" supra-Urgonian formation of Leenhardt (1883), includes only the uppermost terms of the Bedoulian and the lower terms (= Lower and Middle Gargasian) of the Aptian s.s. (i.e., sensu Orbigny, 1840).
Based on the methods of integrated stratigraphy, a comparison of the series of the Apt Basin with the contemporary terms of the Cassis-La Bédoule Basin has also made it possible to detect and quantify important variations in the rhythms of sedimentary accumulation between the two sectors. In the end, the Clavaillan section, located 8 km WSW from the Gargas section, is the only outcrop where the boundary between the Grandis Subzone and the Furcata Zone is visible in a context which supports a proposal that this exposure be a candidate for the GSSP of the Gargasian substage (or of the Aptian s.s. in the initial concept of the creator of the stage).

Carnets Geol., vol. 17, no. 9, p. 161-189

Online since October 20, 2017


Revision of the Barrande's specimen "Tige d'une Cystidée indéterminée" (Cambrian, Echinodermata, Eocrinoidea)
Martina NOHEJLOVÁ & Oldřich FATKA

 | HTML  | PDF [548 KB]  | DOI: 10.4267/2042/62768

 Abstract:  Reexamination of the type specimen described by Barrande in 1887 as "Tige d'une Cystidée indéterminée" shows that this unique specimen represents an articulated but incomplete remnant of the gogiid eocrinoid Akadocrinus jani Prokop. The specimen is preserved as an external mould in shale from the mid-Cambrian Jince Formation, and comprises a proximal part of a stem associated with a slightly disarticulated distal portion of a theca, composed of over twenty polygonal plates. With the exception of the basal-most plates, all other preserved thecal plates bear ellipsoidal marginal epispires, and substantiate assignment of this specimen to the epispire-bearing phase in ontogenetic development of Akadocrinus.

Carnets Geol., vol. 17, no. 8, p. 153-160

Online since October 16, 2017


Rare rugosan-bryozoan intergrowth from the Upper Ordovician of Estonia
Olev VINN, Andrej ERNST & Ursula TOOM

 | HTML  | PDF [1,517 KB]  | DOI: 10.4267/2042/62664

 Abstract:  Two relatively large specimens of the rugosan Lambelasma sp. are fully intergrown with the bryozoan Stigmatella massalis colony. The intergrown specimen occurs in the Oandu Regional Stage (lower Katian) of Estonia and constitutes the earliest record of bryozoan-rugosan intergrowth from Baltica. Most likely this symbiotic association was accidental. Rugosans presumably benefitted from the bryozoan, which served as an anchor to stabilize them in hydrodynamically active waters. The lack of malformations and no decrease in the size of bryozoan zooids near the rugosans indicate a lack of negative effect of the rugosans on the bryozoan. Bryozoan-rugosan symbiosis is only known from the Ordovician of Baltica and Laurentia.

Carnets Geol., vol. 17, no. 7, p. 145-151

Online since October 16, 2017


The most distal moldavite findings from Lower Silesia, Poland
Tomasz BRACHANIEC

 | HTML  | PDF [1,366 KB]  | DOI: 10.4267/2042/62663

 Abstract:  The present note reports new findings of moldavites from southwestern Poland. The material was found in the Nowa Wieś Kącka sandpit. To date, it represents the most distal locality where moldavites have been found. These moldavites, like other moldavites previously described from Lower Silesia, are recovered from fluvial sands and gravels of the Gozdnica Formation. Like other Polish moldavites, the moldavites in this study display high SiO2 contents (~77 wt.%). Their dimensions range from 9 to 11 mm in maximum diameter. Their relatively large sizes suggest that the distribution of Polish tektites defines a sub-strewnfield larger than previously expected.

Carnets Geol., vol. 17, no. 6, p. 139-144

Online since October 16, 2017


Importance of the Quatrehomme collection (Monnaye Museum, Meung-sur-Loire) in the French palaeontological landscape
Morgane DUBIED, Charlène GILBERT, Maxime DELÉGLISE, Flavie LAURENS & Bastien MENNECART

 | HTML  | PDF [528 KB]  | DOI: 10.4267/2042/62541

 Abstract:  The Quatrehomme collection is described by Ginsburg as "modest to very modest" and there is no accurate inventory. In order to highlight this collection and better understand its importance, an inventory of the terrestrial mammal remains is in progress. In the current state of the inventory 35 different locations were identified, mostly in the Savigné-sur-Lathan Basin. 3,266 specimens, covering 8 of the 9 orders of terrestrial mammals found in the Faluns, are currently registered in the data set. To date, the most impressive published Faluns mammal collections are from Hartmann, hosted at the volunteer "Musée du Savignéen" (Savigné-sur-Lathan) and Bourgeois (today splitted in different museums). While this Hartmann's collection contains 1,475 mammal remains (marine and terrestrial) and Bourgeois' one 1850 (only terrestrial), we estimate that the Quatrehomme collection encompasses more than 7,500 terrestrial specimens. It is the largest known Faluns collection of Pliopithecus (25 specimens) and of Lagomorpha (1,355 specimens). Also, eight Tapiroidea specimens (including a jaw with teeth) and three Chalicotherium remains are inventoried. This collection is now being studied in detail. In the next few years it will take a more prominent place in the French paleontological landscape.

Carnets Geol., vol. 17, no. 5, p. 128-138

Online since September 12, 2017


New stratigraphic and genetic model for the dolomitic Cretaceous Pinda reservoirs in Angola. Part I - The Pinda of Angola, an integrated lithostratigraphic approach
Bruno GRANIER

 | HTML  | PDF [6,754 KB]  | DOI: 10.4267/2042/62283

 Abstract:  The Pinda Group of the Congo basin in the northern Angolan offshore is an overall transgressive supersequence of late Aptian - ? early Cenomanian age. Due to synsedimentary salt tectonics of the underlying Loeme Salt, the original ramp arrangement is split into discrete structures corresponding to many proven, probable and possible oil and gas plays. Where the biostratigraphic information was not destroyed by pervasive dolomitization, the little that remains is not available to the general public because it is treated as proprietary data by the Sociedade Nacional de Combustíveis de Angola Empresa Pública – Sonangol E.P. Only a limited set of data containing lithostratigraphic information (e.g., some published well logs and photomicrographs of facies) is available. The aim of this paper is to give a little more information about the Pinda stratigraphy. For instance, to be formally defined, this poorly known unit required a type section, a shortcoming that is addressed here. The wireline log signatures of some regional seismic markers are documented because they are used to correlate wells and subdivide the Group into formations. The microfacies corresponding to some key electrofacies as well as the porosity types are also condensed in a microphotograph catalog. Finally, few examples of typical LoC (i.e., Line of Correlation) diagrams are displayed and interpreted.

Carnets Geol., vol. 17, no. 4, p. 105-127

Online since June 25, 2017


Sedimentological investigation on Holocene deposits in the Mussafah channel (Abu Dhabi, United Arab Emirates)
Bruno GRANIER & Robert BOICHARD

 | HTML  | PDF [21,535 KB]  | DOI: 10.4267/2042/62267

 Abstract:  Eight macrofacies types (5) plus subtypes (3) were identified while measuring sections along the Mussafah channel profile. These include:
• aeolian sands,
• microbial mat and microbial-laminated sediments,
• gypsum and enterolithic anhydrite, i.e., a diagenetic variation of the previous facies,
• muds with small pelecypods, and • its seagrass meadow version,
• Potamid sands, and • its cemented version, i.e., the Potamid beach-rock,
• washover fan coquina.

A complete set of analyses, including granulometry, mineral composition, clay composition, TOC, and identification of the allochems and the microfossils, was performed on this material. The facies and their genetic setting, i.e., the sequence of facies, provide a perspective on both the environmental and stratigraphical significance of their distribution, both lateral and vertical, and an example of the application of the Walther's law. The lower microbial mat is the mark of a transgression whereas the upper microbial mat is the mark of a forced regression. In conclusion, the sequence of facies allows identification of the last Holocene transgressive-regressive cycle that includes a forced regression, which probably dates back to 6,000 years BP.

Biostratigraphy and paleoenvironmental reconstruction of the marine lower Miocene Chechiș Formation in the Transylvanian Basin based on foraminiferal assemblages
Szabolcs-Flavius SZÉKELY, Raluca BINDIU-HAITONIC, Sorin FILIPESCU & Răzvan BERCEA

 | HTML  | PDF [3,045 KB]  | DOI: 10.4267/2042/62041

 Abstract:  Planktonic and benthic foraminiferal assemblages were used for biostratigraphy and paleoenvironmental reconstruction of the marine lower Miocene Chechiș Formation from the Gălpâia section (Sălaj county, Romania) in the northwestern Transylvanian Basin. Planktonic foraminifera suggest an Eggenburgian (Burdigalian) age for the deposits studied and reveal episodes of high primary productivity and mostly cool surface waters. Benthic foraminiferal assemblages indicate paleoenvironmental deepening from outer shelf to upper bathyal settings. Deltaic influences may be observed at the base of the studied section in outer shelf (possibly upper bathyal) environments with oxygenated bottom water and episodic high primary productivity, as a consequence of nutrient input from the land. Changes in paleobathymetry resulted in reduction of primary productivity. The benthic assemblages from the uppermost part of the section are dominated by tubular agglutinated foraminifera and indicate an upper bathyal setting with low organic flux to the sea floor. The sediments of the studied section were deposited during the late stage of the first early Miocene relative sea-level rise in the Transylvanian Basin.

Carnets Geol., vol. 17, no. 2, p. 11-37

Online since March 24, 2017


Review of the early Albian ammonites of the Montmell Formation near Marmellar (Salou-Garraf Basin, Tarragona, Catalonia, Spain)
Josep A. MORENO-BEDMAR, Emmanuel ROBERT, Rafel MATAMALES-ANDREU & Telm BOVER-ARNAL

 | HTML  | PDF [1,482 KB]  | DOI: 10.4267/2042/62038

 Abstract:  In this work, we review the ammonites of the Montmell Formation in the Marmellar area housed in the collections of the Museo Geológico del Seminario de Barcelona and the Museu de Geologia de Barcelona. This taxonomic update allows the proper biostratigraphic analysis of the ammonite assemblage and assigns it to the early Albian, Leymeriella tardefurcata Zone. The taxonomic analysis of all the studied material allows us to recognize the presence of the following taxa: Uhligella sp., Parengonoceras bassei, Hypacanthoplites plesiotypicus, Hypacanthoplites milletianus, Hypacanthoplites subelegans, and Hypacanthoplites sp. The current work is a step forward in the chronostratigraphic knowledge of the Salou-Garraf Basin in the Catalan Coastal Ranges.

Carnets Geol., vol. 17, no. 1, p. 1-10

Online since March 24, 2017


up2  

2016 (vol. 16)

New record of endolithic algae syn-vivo associated with an Early Cretaceous coral
Bogusław KOŁODZIEJ, Vyara IDAKIEVA, Marin IVANOV & Klaudiusz SALAMON

 | HTML  | PDF [1,911 KB]  | DOI: 10.4267/2042/61885

 Abstract:  Euendolithic microorganisms (boring endoliths) syn-vivo associated with modern corals are commonly reported, but their fossil record is extremely rare. This paper reports the new finding recognized in the colonial scleractinian coral Clausastrea saltensis from the Upper Barremian of Bulgaria. Large microborings (up to 50 µm, most ca. 15-25 µm in diameter) filled with calcite cement are distributed medially along coral septa of some corallites. Borings were produced by microeuendoliths growing from the skeleton interior outward during the life of the coral host. They are compared to traces produced by the recent oligophotic filamentous chlorophyte Ostreobium, which is known to be the most common skeleton-dwelling alga in modern living corals and regarded as neutral or beneficial to the coral. In terms of general morphology, diameter and distribution pattern, the borings are similar to those recently recognized in the Early Cretaceous microsolenid coral.

Carnets Geol., vol. 16, no. 27, p. 633-640

Online since December 31, 2016


Early Cretaceous Toxasterid Echinoid Heteraster from the high Zagros basin, south of Iran
Mazaher YAVARI, Mehdi YAZDI, Hormoz GAHALAVAND, Hossein KAMYABI SHADAN, Mohammad Hossein ADABI & Loïc VILLIER

 | HTML  | PDF [8,137 KB]  | DOI: 10.4267/2042/61883

 Abstract:  Two species of spatangoid echinoid belonging to Heteraster Orbigny, 1853, are described from Lower Cretaceous deposits (Gadvan and Dariyan formations) at the Kuh-e Gadvan and Banesh sections situated in Zagros Mountains, south of Iran. Heteraster couloni (Agassiz, 1839) is confirmed in the Barremian and Heteraster delgadoi (Loriol, 1884) in the late Aptian-Albian of Iran. The occurrences of Heteraster and other spatangoid echinoids in Iran show a clear distinction between assemblages from the southern and northern margins of the Tethys during the Early Cretaceous.

Carnets Geol., vol. 16, no. 26, p. 615-632

Online since December 31, 2016


Albian and Cenomanian ammonites of the Eastern margin of the Lut block (East Iran)
Javad SHARIFI, Seyed Naser RAISOSSADAT, Maryam MORTAZAVI MEHRIZI & Maryam MOTAMEDALSHARIATI

 | HTML  | PDF [1,301 KB]  | DOI: 10.4267/2042/61850

 Abstract:  Upper Albian and Lower Cenomanian ammonites occur on the eastern margin of the Lut block in eastern Iran. The ammonite assemblages described herein are from the Nimbolook and Kerch sections located west of Qayen. The following taxa are described: Mantelliceras mantelli (J. Sowerby, 1814), Mantelliceras saxbii (Sharpe, 1857), Mantelliceras sp. 1, Mantelliceras sp. 2, Mantelliceras sp. 3, Sharpeiceras laticlavium (Sharpe, 1855), Sharpeiceras schlueteri (Hyatt, 1903), Puzosia (Puzosia) mayoriana (Orbigny, 1841), Hyphoplites costosus C.W. Wright & E.V. Wright, 1949, Mortoniceras (Mortoniceras) cf. fallax (Breistroffer, 1940), Mantelliceras cf. mantelli (J. Sowerby, 1814), Calycoceras (Gentoniceras) aff. gentoni (Brongniart, 1822), Idiohamites fremonti (Marcou, 1858), Mariella (Mariella) sp., Mariella (Mariella) dorsetensis (Spath, 1926), and Turrilites costatus Lamarck, 1801. The ammonite assemblages clearly indicate a late Albian-middle Cenomanian age for the Nimbolook section and late Albian-early Cenomanian age for the Kerch section.

Carnets Geol., vol. 16, no. 25, p. 591-613

Online since December 12, 2016


Upper Cretaceous non-marine ostracods from the southern High Plateaus, eastern Morocco
Bernard ANDREU, Hamid HADDOUMI & André CHARRIÈRE

 | HTML  | PDF [3,505 KB]  | DOI: 10.4267/2042/61848

 Abstract:  The marls of the upper part of the Tigri Formation in the Upper Cretaceous of the southern High Plateaus, eastern Morocco, reveal non-marine ostracod faunas from freshwater to oligohaline environments. Despite the poor specimen preservation, 23 species belonging to 14 genera have been recognized. The generic assemblages show a global paleobiogeographic distribution both on Laurasia and Gondwana.

Carnets Geol., vol. 16, no. 24, p. 569-590

Online since December 12, 2016


Evolution of Miocene siliciclastic deposits in central Tunisia: Case study of the Khechem El Artsouma section
Hanene BELGHITHI, Frédéric BOULVAIN, Chokri YAICH & Anne-Christine DA SILVA

 | HTML  | PDF [1,255 KB]  | DOI: 10.4267/2042/61846

 Abstract:  After a NE-SW folding phase (Atlasic direction) during the Miocene, siliciclastic sediments from a deltaic environment were deposited in the south-western part of Tunisia while an internal offshore platform formed in the north-eastern part of the country. In this paper we focus on the Khechem El Artsouma Miocene section which is representative of central Tunisia deposits. This area is particularly interesting to study, because it corresponds to a transition zone between deltaic and shallow marine deposits. Facies analysis, magnetic susceptibility measurements and carbonate content measurements are combined to propose a reconstruction of the paleoenvironments and their evolution through the Miocene. Eight facies are identified, from fluviatile, swamp and evaporitic lagoon environments to shore environments. The deposits of the Ain Grab Formation (Langhian) are interpreted as transgressive, followed by the Beglia Formation (Serravalian), which are interpreted as regressive. The whole Saouaf formation (Upper Serravalian - Lower Tortonian) corresponds to a transgressive and regressive sequence. The Djebel Khechem El Artsouma section permits the proposal of a complete sedimentary model for the Miocene deposits from this central Tunisia transition zone.

Carnets Geol., vol. 16, no. 23, p. 557-568

Online since December 12, 2016


On the type species of Lingularia, and description of Eolingularia n. gen.
Maria Aleksandra BITNER & Christian C. EMIG

 | HTML  | PDF [1,301 KB]  | DOI: 10.4267/2042/56006

 Abstract:  The material under study has previously been identified as Lingula krausei, collected from glacial erratics at Cape Rozewie, Poland. All specimens come from glauconitic sandstone of Cenomanian age. Dames (1874) identified his Lingula sp. as L. krausei which differs in shell outline from Lingula truncata. This species, dedicated to A. Krause, together with L. subovalis, is considered characteristic of the Cenomanian. Several new species and genera have recently been described or redescribed and compared to our specimens, here identified as Lingularia similis. By priority (ICZN, 1999), the type species L. similis is currently synonymized with Lingula krausei. A new genus Eolingularia, within the Family Lingulidae, is here described, with Lingularia siberica Biernat et Emig, 1993, as type species. This new genus ranges from the Carboniferous to the Triassic in Russia, China, and Spain. Possible synonymies are discussed.

Carnets Geol., vol. 16, no. 22, p. 543-555

Online since December 12, 2016


Albian rudist biostratigraphy (Bivalvia), Comanche shelf to shelf margin, Texas
Robert W. SCOTT, Whitney CAMPBELL, Rachel HOJNACKI, Yulin WANG & Xin LAI

 | HTML  | PDF [4,372 KB]  | DOI: 10.4267/2042/61701

 Abstract:  Rudists were widespread and locally abundant carbonate producers on the Early Cretaceous Comanche Shelf from Florida to Texas, and on Mexican atolls. As members of the Caribbean Biogeographic Province, their early ancestors emigrated from the Mediterranean Province and subsequently evolved independently. Comanchean rudists formed biostromes and bioherms on the shelf interior and at the shelf margin. Carbonate stratigraphic units of the Comanche Shelf record rudist evolution during the Barremian through the Albian ages and an established zonal scheme is expanded.
This study documents new Albian rudist occurrences from the Middle-Upper Albian Fredericksburg and Washita groups in Central and West Texas. Rudists in cores at and directly behind the shelf margin southeast of Austin and San Antonio, Texas, complement the rudist zonation that is integrated with ammonites and foraminifers. These new rudist data test long-held correlations of the Edwards Group with both the Fredericksburg and Washita groups based solely on lithologies. Rudist and foraminifer biostratigraphy indicate that the Edwards Group is coeval with the Fredericksburg not the Washita Group.
In West Texas sections Caprinuloidea romeri occurs at the top of the Fredericksburg Group in the Fort Terrett Formation approximately 3 meters below the iron-stained hardground subaerial exposure surface. It is overlain by the Washita Group with the ammonite Eopachydiscus marcianus Zone. Caprinuloidea romeri is also documented from the type cored section of the Person Formation in the upper part of the Edwards Group. These species allow a precise correlation of the subsurface Person Formation in Central Texas with the Ft. Terrett Formation cropping out in West Texas. This evidence together with foraminifer and ammonite zones demonstrates that the Person Formation is coeval with Fredericksburg units underlying the basal Washita sequence boundary Al Sb Wa1. The upper Albian Washita Group Kimbleia and Mexicaprina caprinid zones overly the Caprinuloidea Zone and the successive Washita mortonicerid ammonite zones.

Carnets Geol., vol. 16, no. 21, p. 513-541

Online since November 11, 2016


Jurassic-Cretaceous transition on the Getic carbonate platform (Southern Carpathians, Romania): Benthic foraminifera and algae
Cristian Victor MIRCESCU, George PLEŞ, Ioan I. BUCUR & Bruno GRANIER

 | HTML  | PDF [4,910 KB]  | DOI: 10.4267/2042/61824

 Abstract:  The carbonate succession of the Piatra Craiului Massif, i.e., the eastern part of the Getic carbonate platform (Southern Carpathians, Romania), comprises reefal and peritidal limestones that contain a diverse microfossil assemblage composed mainly of calcareous green algae and benthic foraminifera. The biostratigraphically most significant benthic foraminifera found in the several sections studied are described; some (Anchispirocyclina lusitanica, Neokilianina rahonensis, Bramkampella arabica, Everticyclammina praekelleri) are reported for the first time in this area. Hence, assemblages of both foraminifera and calcareous algae characterize three biostratigraphic intervals in the studied succession, the Kimmeridgian - lower Tithonian, the upper Tithonian - lower Berriasian, and the upper Berriasian - ? lower Valanginian intervals. The main microfacies types (bioclastic rudstone, coral-microbial boundstone, bioclastic grainstone, interbedded mudstones and wackestones with cyanobacteria nodules) as well as both the foraminifera and the calcareous algae are paleoecological indicators that may contribute to the decipherment of the depositional environments and to building a depositional model for the eastern part of the Getic carbonate platform at the Late Jurassic-Early Cretaceous transition.

Carnets Geol., vol. 16, no. 20, p. 491-512

Online since October 24, 2016


The Weberg and Warm Spring Members of the Snowshoe Formation in Suplee area, Oregon: Lithofacies and Aalenian-early Bajocian ammonoid zonation
David G. TAYLOR

 | HTML  | PDF [2,653 KB]  | DOI: 10.4267/2042/61389

 Abstract:  This paper documents the stratigraphic information upon which an ammonoid zonation from the lower part of the Snowshoe Formation in the Suplee area was originally established (Taylor, 1988). Ammonoid ranges from 22 measured stratigraphic sections reveal about 60 ammonoid species distributed among eight zones encompassing the late Aalenian and part of the early Bajocian stages. The sediments are dominantly volcaniclastic and, as a result, there are numerous tuff beds in the succession. As noted in Taylor (1982) the principal tuff beds (herein designated as units A through F) can be used jointly with the ammonite sequence to give precise correlations from section to section. Utilizing the ammonoids, tuff beds, and facies in combination gives a graphic representation of the westward transgression of the Snowshoe Formation as it enveloped an irregular topography, and lapped onto the topographically high Grindstone High to the west. The ammonoid zonation is significant in that it gives a standard of reference for the biochronology of the late Aalenian and early Bajocian ammonoids in the North American Western Cordillera.

Carnets Geol., vol. 16, no. 19, p. 449-490

Online since September 12, 2016


Plio-Pleistocene Ostracods from sedimentary sections along the eastern edge of Cape Bon (Wadi Lebna section, Eastern Tunisia)
Rim TEMANI, Driss NACHITE, Francesco SCIUTO, Saloua RAZGALLAH, Ratiba BEKKALI, Khayati HAYET & Nadia GAALOUL

 | HTML  | PDF [3,155 KB]  | DOI: 10.4267/2042/61387

 Abstract:  This paper presents for the first time a detailed study of ostracods in the Upper Pliocene-Lower Pleistocene deposits of Wadi Lebna (Cape Bon eastern edge, northeastern Tunisia). The quantitative and qualitative analyses document the evolution of this area from a marine environment dominated by relatively deep or circalittoral species at the base of the succession, passing progressively up into shallower environments, and at the top infralittoral coastal environments. Particularly important from the ecological point of view is the presence in some samples of Bythocythere turgida. This species indicates deposition of these sediments during the cold phases of the Early Pleistocene.

Carnets Geol., vol. 16, no. 18, p. 431-447

Online since September 12, 2016


Comments on "Estimating the impact of early diagenesis on isotope records in shallow-marine carbonates: A case study from the Urgonian platform in western Swiss Jura" by A. Godet et al. [Palaeogeography Palaeoclimatology Palaeoecology 454 (2016) 125-138]
Bruno GRANIER, Bernard CLAVEL & Jean CHAROLLAIS

 | HTML  | PDF [806 KB]  | DOI: 10.4267/2042/61385

 Abstract:  A recent paper by Godet et al. on Urgonian carbonates from the Swiss Jura concluded that diagenesis may hinder chemostratigraphic correlations of deep- to shallow-water facies. Although we agree with this conclusion we question their arguments and interpretations. These authors correctly identified diagenesis as the key factor, but we question the timing of events in their paragenetic sequence. In particular, they reported the leaching of originally calcitic oolitic cortices but failed to discuss this puzzling feature properly. In addition, the backbone of their argument is the stratigraphic correlation of a specific sequence from three dominantly shallow-water sections together with a basinal reference section. However, a reliable alternative biostratigraphic framework shows that this attempt of long-distance correlation might be erroneous.

Carnets Geol., vol. 16, no. 17, p. 417-429

Online since August 5, 2016


Taxonomy and distribution of the Cretaceous coral genus Eosiderastrea
Hannes LÖSER

 | HTML  | PDF [6,545 KB]  | DOI: 10.4267/2042/60677

 Abstract:  The new genus Eosiderastrea Löser, 2016, was established for Cretaceous corals formerly assigned to the extant coral genus Diploastrea. It represents the oldest member of the Family Siderastraeidae. The genus is characterised by an astreoid arrangement, occasionally although some have a plocoid or a cerioid calicular arrangement, and a sub-regular hexameral, heptameral, octameral or decameral septal symmetry. The septal blades are made of medium-sized trabeculae. Synapticulae are present. Almost a hundred specimens were examined, among them numerous type specimens. In total, 26 Cretaceous species were separated. Fifteen species were assigned to formally established species, three species were compared to one of these species, two species were described as new and the remaining six species were reported in open nomenclature. The genus occurs in the Cretaceous worldwide and ranges from the late Valanginian to the Santonian. It shows its greatest diversity in the earliest Aptian and early to middle Cenomanian.

Carnets Geol., vol. 16, no. 16, p. 383-416

Online since July 7, 2016


Ivaldiceras, a new genus of heteromorphic ammonites from the Lower Aptian of southeast France
Gérard DELANOY, Cyril BAUDOUIN, Marc BOSELLI & Emmanuel PENAGÉ

 | HTML  | PDF [2,479 KB]  | DOI: 10.4267/2042/60676

 Abstract:  New investigations in the Vocontian Lower Aptian deposits resulted in the discovery of very rare specimens of heteromorphic ammonites whose specific morphological and ornamental features have led to the erection of Ivaldiceras gen. nov. Represented by a very limited number of specimens this new genus consists of two species: I. baratteroi gen. & sp. nov. and I. divajeuensis gen. & sp. nov. The suprageneric position of the new genus is difficult to determine because of the poor preservation of its sutural elements and the incomplete state of the specimens. The genus is tentatively assigned to the Family Macroscaphitidae Hyatt, 1900, pending the study of better preserved material.

Carnets Geol., vol. 16, no. 15, p. 369-381

Online since July 7, 2016


Aptian ammonites from Mazapil, Zacatecas State (north-central Mexico) studied by Burckhardt in 1906: A revision
Ricardo BARRAGÁN, Josep Anton MORENO-BEDMAR & Celestina GONZÁLEZ-ARREOLA

 | HTML  | PDF [2,306 KB]  | DOI: 10.4267/2042/60667

 Abstract:  Twelve specimens of Aptian ammonites reported and drawn by Burckhardt in 1906, from the Mazapil area (Zacatecas State, north-central Mexico), are reviewed for taxonomical purposes. The work by Burckhardt was the first report of Aptian ammonoids in Mexico. In addition, it represents the only record of Aptian ammonites known from Zacatecas State. The taxonomic review of the specimens allows for the recognition of Dufrenoyia sp., Colombiceras spathi Humphrey, Colombiceras mexicanus (Humphrey) n. comb., Colombiceras sp., Colombiceras spp., and Acanthohoplites aff. bigoureti (Seunes). This ammonite assemblage is indicative of a stratigraphic range that spans the uppermost lower Aptian to the upper Aptian interval.

Carnets Geol., vol. 16, no. 14, p. 355-367

Online since June 23, 2016


Possible vertebrate coprolites from the Upper Cretaceous (Coniacian) of the Sudetes Mountains (southern Poland)
Tomasz BRACHANIEC & Anna WIECZOREK

 | HTML  | PDF [559 KB]  | DOI: 10.4267/2042/60665

 Abstract:  Possible coprolites from the Upper Cretaceous (Coniacian) of Waliszów Stary in the Sudetes Mountains (southern Poland) are described for the first time. They are relatively small, irregular in outline, and preserved as goethite, limonite, siderite and hematite. Although it is difficult to identify the producer of these coprolites, they were most probably formed by some fish.

Carnets Geol., vol. 16, no. 13, p. 349-354

Online since June 23, 2016


Late Albian cactus in shallow carbonate shelf, West Texas
Robert W. SCOTT, Zexuan WANG, Xin LAI & Yulun WANG

 | HTML  | PDF [665 KB]  | DOI: 10.4267/2042/60122

 Abstract:  Well-preserved vertical molds of a stalk-like fossil are in growth position in the upper part of the Upper Albian Fort Lancaster Formation exposed in West Texas. The Fort Lancaster Formation is the uppermost Albian carbonate unit deposited on the shallow water Barremian-early Cenomanian Comanche shelf. The Fort Lancaster represents one long-term transgressive-regressive cycle capped by a regional unconformity overlain by lower Cenomanian deeper water Del Rio Shale.
The erect stalk-like molds are up to 1 m tall and about 6 cm in diameter. The mold walls are composed of six pairs of angular ridges and grooves evenly spaced at an angle of 60° to each other. The ridge crests are dotted by paired ringed depressions with small central nodes; these negative impressions indicate the presence of oval rings with small depressions inside of each ring. The diameter of the stalk is the same at its base as at its top indicating that growth did not expand the organism but extended it upward. These stalk-like organisms appear to be rooted on disconformable bedding surfaces that were exposed to the atmosphere. Carbon isotope data shows the classic negative shift below subaerial contacts. Subsequently sea level rose and muddy carbonate sediment buried the stalk. The absence of original wall material suggests that the wall was composed of readily decayed or dissolved material such as organic matter or aragonite. Stalk-like organisms of this size and shape are rare and potential types are cacti, plant reeds, Porifera, or Scleractinian Cnidaria.

Carnets Geol., vol. 16, no. 12, p. 337-346

Online since May 19, 2016


The taxonomy of middle Miocene red algae from the Gârbova de Sus Formation (Transylvanian Basin, Romania)
Ramona CHELARU & Ioan I. BUCUR

 | HTML  | PDF [3,439 KB]  | DOI: 10.4267/2042/60121

 Abstract:  This study describes seventeen non-geniculate coralline algal species (orders Corallinales, Hapalidiales and Sporolithales) from the middle Miocene (lower-middle Badenian) red-algal limestones of the Transylvanian Basin, Gârbova de Sus Formation. For the description and identification at species level, we follow the common diagnostic features used for fossil species and some characters that are used as diagnostic for modern species (roof morphology for asexual conceptacles, the presence/absence of a layer of elongated cells below sporangial compartments and number of cells in paraphyses for Sporolithon, and measurements of gametangial and carposporangial conceptacles). Female conceptacles of Spongites fruticulosus Kützing are for the first time described in fossil material. We propose the attribution of Lithophyllum platticarpum Maslov to Spongites fruticulosus Kützing as a gametangial thallus with male conceptacles.

Carnets Geol., vol. 16, no. 11, p. 307-336

Online since May 19, 2016


Environmental control on shell size of Middle Triassic bivalve Plagiostoma
Krzysztof R. BROM, Robert NIEDŹWIEDZKI, Tomasz BRACHANIEC, Bruno FERRÉ & Mariusz A. SALAMON

 | HTML  | PDF [254 KB]  | DOI: 10.4267/2042/60118

 Abstract:  Fossil shells of the marine bivalve Plagiostoma striatum Schlotheim sampled from the Middle Triassic (so-called Muschelkalk) of Poland demonstrate that, under unfavourable environmental conditions, this species commonly occurring in Triassic German basins exhibits a dwarfed shell. As a consequence of a marine regression episode resulting in a significant increase of salinity and a partial emersion of seafloor these bivalves vanished. The next transgressive pulse caused a re-emergence of these bivalves. They were initially characterized by half-size shells than in the population living prior to the regression episode and, subsequently, during progressive transgression, their shells returned to normal size. Coincidence between eustatic curve and changes in bivalve shell size and their disappearance may be attributed also to biotic interactions, such as a biotic collapse in primary bioproductivity or/and a competition for space or any other resources due to shelf habitat loss during regressive periods.

Carnets Geol., vol. 16, no. 10, p. 297-305

Online since May 21, 2016


Lithostratigraphic, paleoenvironmental and sequential evolution of the Cenomanian-Lower Turonian in the Guir area (western Algeria)
Madani BENYOUCEF, Christian MEISTER, Kaddour MEBARKI, Émilie LÄNG, Mohammed ADACI, Lionel CAVIN, Fatima-Zohra MALTI, Djamila ZAOUI, Amine CHERIF & Mustapha BENSALAH

 | HTML  | PDF [2,328 KB]  | DOI: 10.4267/2042/59926

 Abstract:  The lithostratigraphy, paleoenvironment and sequence stratigraphy of the Cretaceous succession outcropping at the southern foot of the Saharan Atlas (south-western Algeria) are discussed in this work. Our current study focuses on the analysis of fifteen sections distributed along to the northern and southern limits of the Guir Basin, between the Ben-Zireg to the East and the Meridja-Boukais axis to the West. In this area, three lithostratigraphic formations were identified and interpreted from an environmental and a sequential points of view: 1 - The lower "Grès rouges" Formation attributed to the Lower Cenomanian, is dominated by fluvial or coastal detrital deposits; 2 - The middle "Marnes à gypse inférieures" Formation assigned to the Lower-Middle Cenomanian is characterized by littoral setting with some storm influences, especially towards the base; 3 - The upper "Calcaires de Sidi Mohamed Ben Bouziane" Formation of upper Cenomanian-early Turonian in age, is represents a laterally extensive, shallow carbonate platform environment. The three formations constitute an overall transgressive megasequence built of a number of transgressive-regressive minor sequences. The opening of the deposits towards the North is confirmed by the organization of the lithostratigraphic units and by the Tethyan paleobiogeographic affinity of the echinoids and bivalves, and especially the occurrence of Neolobites vibrayeanus ammonite.

Carnets Geol., vol. 16, no. 9, p. 271-296

Online since April 14, 2016


Some steps toward a new story for the Jurassic - Cretaceous transition in Mount Lebanon
Bruno GRANIER, Christopher TOLAND, Raymond GÈZE, Dany AZAR & Sibelle MAKSOUD

 | HTML  | PDF [2,066 KB]  | DOI: 10.4267/2042/59924

 Abstract:   The stratigraphic framework of the Upper Jurassic and Lower Cretaceous strata of Lebanon that dates back to Dubertret's publications required either consolidation or full revision. The preliminary results of our investigations in the Mount Lebanon region are presented here. We provide new micropaleontological and sedimentological information on the Salima Oolitic Limestones, which is probably an unconformity-bounded unit (possibly Early Valanginian in age), and the "Grès du Liban" (Barremian in age). Our revised bio- and holostratigraphic interpretations and the new age assignations lead us to emphasize the importance of the two hiatuses in the sedimentary record below and above the Salima, i.e., at the transition from the Jurassic to the Cretaceous.

Carnets Geol., vol. 16, no. 8, p. 247-269

Online since April 14, 2016


On the fossil alga Marinella lugeoni Pfender, 1939, nom. cons., and its seven unfortunate avatars. Revision of the Juliette Pfender Collection. Part 2. Revision of the Jesse Harlan Johnson Collection. Part 2
Bruno GRANIER & Dimas DIAS-BRITO

 | HTML  | PDF [1,378 KB]  | DOI: 10.4267/2042/59922

 Abstract:   A review of eight lookalike fossil species led to their being synonymized. Although Marinella lugeoni Pfender, 1939, is not the senior synonym, it is proposed to ascribe it the status of a "nomen conservandum". The age of its type-locality in Spain is Late Jurassic, not Early Jurassic. We also document small Marinella lumps found in Albian-Cenomanian strata of Brazil.

Carnets Geol., vol. 16, no. 7, p. 231-245

Online since April 14, 2016


On the fossil alga Elianella elegans Pfender & Basse, 1948, and its so-called lookalikes, with description of Elianella brasiliana n.sp. Revision of the Juliette Pfender Collection. Part 1
Bruno GRANIER & Dimas DIAS-BRITO

 | HTML  | PDF [2,885 KB]  | DOI: 10.4267/2042/59920

 Abstract:  According to some authors, the three fossil algal forms discussed in this paper, Cordilites cretosus (Reus, 1846), Elianella elegans Pfender & Basse, 1948, and Parachaetetes asvapatii Pia in Rao & Pia, 1936, are synonyms. However, we document that they represent three discrete species. The genus Elianella Pfender & Basse, 1948, gets unique features that make it easy to discriminate; we describe a new species from Albian limestones of Brazil. The other two genera, Cordilites Počta, 1887, and Parachaetetes Deninger, 1906, share some common features, such as having a thallus made of a lattice-network with columns (filaments) and rows. However, on the basis of their diagnostic criteria, the species Cordilites cretosus and Parachaetetes asvapatii should not be confused.

Carnets Geol., vol. 16, no. 6, p. 213-229

Online since April 14, 2016


Revision of the Early Cretaceous genera Heminautilus Spath, 1927, and Josanautilus Martínez & Grauges, 2006 (Nautilida, Cenoceratidae)
Cyril BAUDOUIN, Gérard DELANOY, Josep Anton MORENO-BEDMAR, Antoine PICTET, Jean VERMEULEN, Gabriel CONTE, Roland GONNET, Patrick BOSELLI & Marc BOSELLI

 | HTML  | PDF [34,156 KB]  | DOI: 10.4267/2042/58977

 Abstract:  In spite of recent interest, the various species belonging to the genera Heminautilus Spath, 1927, and Josanautilus Martínez & Grauges, 2006, have never been the object of a general revision. More than 160 specimens belonging to various species of these two genera were studied, with the aim of identifying the specific characteristics and the stratigraphical and paleogeographical distribution of the various species which compose them, as well as to propose a phylogeny for the group. This study confirms the non-synonymy of Heminautilus saxbii (Morris, 1848) and H. lallierianus (Orbigny, 1841), establishes that H. tejeriensis Martínez & Grauges, 2006, and H. verneuilli (Vilanova, 1870) represent junior synonyms of H. saxbii (Morris) and suggests the creation of the species H. ? japonicus sp. nov. The origin of the genus Heminautilus Spath from Pseudocenoceras Spath, 1927, proposed by Tintant, and the origin of Josanautilus Martínez & Grauges from Heminautilus Spath are both confirmed.

Carnets Geol., vol. 16, no. 5, p. 61-212

Online since April 14, 2016


Sedimentologic study of palustrine continental carbonate deposits of the Tajerouine area, NW Tunisia
Naoufel GHANNEM, Faouzia TLILI, Chadia RIAHI & Kamel REGAYA

 | HTML  | PDF [1,885 KB]  | DOI: 10.4267/2042/58976

 Abstract:  The palustrine limestones of Quaternary (Middle to the Late Pleistocene) age described in this study are located in the El Gara massif Tajerouine (Northwest of Tunisia). The study of these deposits at different scales, both macroscopic (lithological description) and microscopic (petrography and mineralogy), shows that they have a tabular structure and an angular unconformity contact on the marly – calcareous series from the Aptian-Albian. They show lateral and vertical changes in facies, including conglomerates, limestones and stromatolites. Layer thickness tends to increase gradually from East to West and also to the South of the study area. Because of fluctuations in the groundwater table, these carbonates have undergone periods of flooding and emersion, causing many pedogenic changes. The nature of these changes was controlled by the height of emersion (nodulisation, roots traces, pseudo-microkarst). These pedogenic changes in turn affected cementation during diagenesis (alternations of phreatic cement), justifying the rock classification as palustrine limestone.

Carnets Geol., vol. 16, no. 4, p. 43-59

Online since April 1, 2016


Lithothamnion crispatum: long-lasting species of non-geniculate coralline algae (Rhodophyta, Hapalidiales)
Giovanni COLETTI, Juraj HRABOVSKÝ & Daniela BASSO

 | HTML  | PDF [2,096 KB]  | DOI: 10.4267/2042/58720

 Abstract:  The examination of fossil Lithothamnion specimens ranging in age from the Early Miocene to the Pleistocene revealed the occurrence of multiporate conceptacle chambers pitted with depressions. This is the diagnostic feature of Lithothamnion crispatum, a cosmopolitan hapalidiacean with a wide depth range in modern oceans. The comparison of the microscopic anatomy of both the fossil and modern L. crispatum confirmed that they are conspecific. Therefore, this species has a long stratigraphic distribution starting at least 20 My ago, without significant morphological changes in either reproductive or vegetative anatomy.

Carnets Geol., vol. 16, no. 3, p. 27-41

Online since February 20, 2016


Insights into the permeability of polygonal faults from their intersection geometries with Linear Chimneys: a case study from the Lower Congo Basin
Sutieng HO, Daniel CARRUTHERS & Patrice IMBERT

 | HTML  | PDF [483 KB]  | DOI: 10.4267/2042/58718

 Abstract:  Layer-bound arrays of polygonal compaction faults have long been considered as important migration routes for hydrocarbon fluids leaking to the surface across thick shale sequences. A classic example is the deep offshore of the Lower Congo Basin where numerous fluid-venting structures are present above a Pliocene polygonal fault system. In this paper we present a detailed seismic analysis of a newly recognised system of Quaternary-aged Linear Chimneys and their intersection geometries with pre-existing Pliocene-aged polygonal faults (PF). Most (73%) of the 209 chimneys analysed intersect the lower portions of polygonal faults and almost half of these are rooted in strata below the PF interval. This indicates that fluid (in this case gas) migrated vertically, cross-cutting polygonal faults as it ascended through the tier. This is a strong indicator that PFs did not provide viable migration pathways otherwise chimneys would terminate at the upper tip of the fault, which would be the most likely migration exit point. Only twice in the whole system of Linear Venting Systems did this occur. A sub-set of chimneys stems from or above PF planes but these are restricted to either the lower footwall or from the apex area of hanging wall. At best they are evidence of fluids migrating up the lower part of polygonal faults and exiting deep within the tier, then migrating through most of the tier in their own vertical leakage vents. These results provide strong indicators that at least within this part of the Lower Congo Basin polygonal faults were the least effective/favoured migration pathway and that it was more energy-efficient for migrating gas to hydrofracture its fine-grained overburden than to re-open polygonal faults.

Carnets Geol., vol. 16, no. 2, p. 17-26

Online since February 20, 2016


A simple technique to establish sequences of datums and to highlight transgressive–regressive cycles
Jean GUEX & Federico GALSTER

 | HTML  | PDF [394 KB]  | DOI: 10.4267/2042/58207

 Abstract:  The relative diachronism of first or last local occurrences (FOs and LOs) of fossil species may highlight transgressive/regressive cycles. A simple technique allowing the extraction of this information by means of the UAgraph program is discussed in the present paper. The technique consists in modifying a usual database of UAgraph by augmenting it with the restricted data concerning only the FOs (or LOs) of the taxa under consideration. The resulting data set combines the information on total ranges and those concerning the FOs and LOs only. Calculating the UAs of such a duplicated database produce a range chart in which we can read the maximal ranges of all the taxa and, in addition, the biochronological dispersion of the FOs and LOs. For a given transgressive/regressive cycle, the UAs defined by the species related to sea level fluctuations migrate with time from distal to proximal sections and inversely. This trend can be detected visually by the means of the UAs reproducibility chart, output of the UAgraph program. In a more general frame, the same holds true for species whose regional dispersion is related to specific conditions and when these conditions migrate in space with time (e.g., water temperatures and diatoms). The above discussion is strictly related to FOs and LOs that for a given section are definitive, however well constrained ephemeral appearances and disappearances can be easily integrated in the database for the same purposes.

Carnets Geol., vol. 16, no. 1, p. 1-16

Online since January 14, 2016


up2  

2015 (vol. 15)

A review of the species of the genus Hemidiadema Agassiz, 1846 (Euechinoidea, Camaradonta, Glyphocyphidae), from the Aptian (Lower Cretaceous) of Spain
Arnaud CLÉMENT

 | HTML  | PDF [2,717 KB]  | DOI: 10.4267/2042/58204

 Abstract:   Specimens belonging to the genus Hemidiadema Agassiz, 1846, from Aptian (Lower Cretaceous) strata from the Spanish provinces of Castellón, Tarragona, Barcelona and Teruel –were studied. All specimens of Hemidiadema from these regions cited or described in the literature until now were related to the species Hemidiadema rugosum Agassiz, 1846. Their taxonomic revision – based on historical material and new collecting – demonstrates that these individuals do not belong to the species described by Agassiz, but represent new taxa. Three new species are proposed and described: Hemidiadema batalleri nov. sp., H. malladai nov. sp., and H. forcallensis nov. sp). The species H. rugosum Agassiz, 1846, is known by a single specimen from the Aptian of Castellón. Remarks on the paleoecology and stratigraphic and geographic distributions of these species are given.

Carnets Geol., vol. 15, no. 20, p. 279-330

Online since December 25, 2015


Distribution of Conichnus and Amphorichnus in the Lower Paleozoic of Estonia (Baltica)
Olev VINN, Mark A. WILSON & Ursula TOOM

 | HTML  | PDF [1,137 KB]  | DOI: 10.4267/2042/58180

 Abstract:   Conichnus conicus and Amphorichnus papillatus occur in clay-rich carbonate rocks in the Ordovician of Estonia. Conichnus conicus also occurs in clay-rich carbonates of the early Silurian of Estonia. Lateral adjustment traces are more common in C. conicus than previously recorded. The lack of adjustment traces in Amphorichnus, together with its morphology, does not support synonymy of Conichnus and Amphorichnus. The Conichnus conicus and Amphorichnus papillatus tracemakers preferred shallow water carbonate environments with high clay content. They were rare or did not occur in deeper water muddy environments or where shallow water carbonates accumulated. A high content of volcanic ash in the depositional environment is characteristic of both the Ordovician and Silurian maxima of Conichnus conicus occurrence. C. conicus may have been more common in the temperate seas of Baltica than in the tropics.

Carnets Geol., vol. 15, no. 19, p. 269-278

Online since December 2, 2015


Selected agglutinated larger foraminifera from the Font de les Bagasses unit (early Campanian, southern Pyrenees)
Sergi ALBRICH, Carme BOIX & Esmeralda CAUS

 | HTML  | PDF [5,455 KB]  | DOI: 10.4267/2042/57953

 Abstract:   The Font de les Bagasses marls and marly limestones (Montsec Mountains, NE Spain) host a rich assemblage of larger foraminifera, that was described for the first time in the early 20th Century from the currently submerged locality of Tragó de Noguera (Marginal Mountains). In this paper, a detailed architectural study has been carried out on selected, agglutinated larger foraminifera, which include Choffatella aff. rugoretis Gendrot, Hemicyclammina chalmasi (Schlumberger), Cuneolina conica Orbigny, Cuneolina cylindrica Henson, and Dictyopsella kiliani Munier-Chalmas. Moreover, it presents their biostratigraphic range and the range of the associated porcellaneous and lamellar-perforate foraminifera in the study area. The assemblage is Early Campanian in age.

Carnets Geol., vol. 15, no. 18, p. 245-267

Online since November 18, 2015


Tremichnus in crinoid pluricolumnals from the Silurian of western Estonia (Baltica)
Olev VINN, Mark A. WILSON, William I. AUSICH & Ursula TOOM

 | HTML  | PDF [644 KB]  | DOI: 10.4267/2042/57951

 Abstract:   Quelques petites cavités attribuées à Tremichnus ont été trouvées dans des crinoïdes provenant du Silurien d'Estonie. Ce Tremichnus rhuddanien est le symbiote le plus ancien observé dans des segments de tiges de crinoïdes du bouclier balte. Ces cavités correspondent vraisemblablement à des habitats d'organismes inconnus. Tremichnus a eu un impact négatif sur le crinoïde hôte comme en attestent les renflements des tiges. Tremichnus est moins fréquent dans le Silurien d'Estonie que des traces semblables dans le Silurien du Gotland voisin. L'aspect le plus significatif de cette étude est la rareté de cette interaction dans ces échantillons à la différence de la plupart des échantillons du même âge provenant d'autres localités. Ces structures ont une répartition très irrégulière.

Carnets Geol., vol. 15, no. 17, p. 239-243

Online since November 18, 2015


Scientific death-knell against databases? Errors induced by database manipulations and its consequences
Christian C. EMIG, Maria Aleksandra BITNER & Fernando ÁLVAREZ

 | HTML  | PDF [107 KB]  | DOI: 10.4267/2042/57949

 Abstract:   References to Terebratulina caputserpentis attributing its authorship to Zbyszewski, 1957, not to Linnæus, 1767, have been found in three recent publications, in the collections of the Muséum National d'Histoire naturelle de Paris and in several online databases. The use in these databases seems to have arisen from WoRMS (World Register of Marine Species), specifically from WBD (World Brachiopoda Database) of which the three authors of this paper are the editors (authors). The page concerning T. caputserpentis (Linnæus, 1767) has been modified by WoRMS staff without the knowledge of these editors (authors).
The decrease of the specialists in systematics and their replacement by IT specialists question the scientific reliability of the online databases as well as the specimen labelling in museums. The absence of scientific rigour becomes their Achilles' heel. Several other cases of errors are quoted and developed. In spite of applications to the staff of databases in biodiversity, the situation continued degrading so much so that today these bases are reached by the Peter principle and can no longer be used for scientific requirements, except if verifying all the desired data.

Carnets Geol., vol. 15, no. 16, p. 231-238

Online since November 11, 2015


New fossiliferous sites with Barremian Charophyta in the "Grès du Liban" auct. (Lebanon), with a critical perspective regarding the nature of Munieria Deecke, 1883
Bruno GRANIER, Dany AZAR, Sibelle MAKSOUD, Raymond GÈZE & Roland HABCHI

 | HTML  | PDF [5,904 KB]  | DOI: 10.4267/2042/57947

 Abstract:   The "Grès du Liban" auct. is the thick basal unit of the Lower Cretaceous series in Lebanon. There are two key levels in this dominantly siliciclastic unit: the "Banc de Mréjatt" and the "Calcaire à pisolithes", the latter of which includes limestones and marls with Charophyta. The rich charophyte assemblage described by Grambast and Lorch (1968) from a site near Jezzine is Barremian (possibly Early Barremian) in age, not Bedoulian as previously stated. Besides gyrogonites and utricles, charophyte thalli are rather common; they are ascribed to two organ genera, Munieria Deecke, 1883, and Charaxis Harris, 1939. Based on topotypic material (from the Pia Collection), Munieria baconica Deecke, 1883, the type-species of the genus, is reassessed. In addition, the species Clypeina parvula Carozzi, 1946, is transferred to the revised genus Munieria, and a new species of Charaxis is described.

Carnets Geol., vol. 15, no. 15, p. 199-229

Online since November 11, 2015


Palaeoenviromental and palaeogeographical traits on deep-water ostracod assemblages from the Lower Pleistocene sediments along the Ionian side of Mount Etna (Sicily, Italy)
Francesco SCIUTO

 | HTML  | PDF [2,013 KB]  | DOI: 10.4267/2042/57945

 Abstract:   The ostracod associations of the Lower Pleistocene sedimentary succession cropping out at Serra San Biagio (Catania, Sicily NE) have been investigated. The ostracod fauna from nine samples is poorly diversified but well-preserved: A total of forty taxa of ostracods have been identified, thirty-three at specific level and seven at genus level or doubtful species. Thirty species are considered as constituents of the in situ original assemblages. The associations consist almost exclusively of bathyal taxa such as Bythocypris obtusata (Sars), Anchistrocheles antemacella Maddocks, Henryhowella ex H. hirta (Costa) group, Quasibuntonia radiatopora (Seguenza), Retibythere (Bathybythere) scaberrima (Brady) and Bathycythere vansraateni Sissingh. Also the Krithe group is well-represented with Krithe compressa (Seguenza) and K. pernoides (Bornemann). Almost all species, some, particularly interesting from the palaeoecological and palaeogeographical point of view, have been here described, illustrated and commented on, including a species belonging to the genus Cytherella Jones, 1849, found in all samples of the section, which is here proposed as new.

Carnets Geol., vol. 15, no. 14, p. 179-197

Online since November 11, 2015


Review of some Aptian ammonites collected by Gaston Astre in Lleida Province, Catalonia, Spain
Josep A. MORENO-BEDMAR & Keith P. MINOR

 | HTML  | PDF [934 KB]  | DOI: 10.4267/2042/56911

 Abstract:   We study the three best preserved ammonites collected by Astre in 1924-1925 in Lleida Province, Catalonia, Spain, in order to assess their taxonomic assignment. We also include images of these ammonoids since they were not illustrated in Astre's original 1934 work. This taxonomic review allows us to identify these lower Aptian ammonites as Pseudohaploceras liptoviense, Deshayesites sp. and Dufrenoyia sp.

Carnets Geol., vol. 15, no. 13, p. 173-178

Online since August 6, 2015


Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)
Badre ESSAFRAOUI, Serge FERRY, Danièle GROSHÉNY, Nourrisaid IÇAME, Hassan EL AOULI, Moussa MASROUR, Luc G. BULOT, Yves GÉRAUD & Mohamed AOUTEM

 | HTML  | PDF [24,372 KB]  | DOI: 10.4267/2042/56909

 Abstract:   Seven sections, covering the upper Albian to lowermost Turonian, have been correlated from full-marine to continental-dominated deposits across a passive margin, along a transect 425 km long, from the present-day Atlantic coast to the "Pre-African Trough" between the Anti-Atlas and the High-Atlas. The thickness of the Cenomanian succession changes from around 500 metres in the fully marine sections to 250 metres in mostly continental facies in the western High-Atlas, about 150 km updip, to a few tens of metres in the Bou Tazoult area. The strata thicken again eastwards into the Pre-African Trough where they can be traced without major facies changes to the Kem Kem embayment and to the Bechar area in Algeria. Over all this eastern area, continental facies are overlain by the fully-marine shallow-water deposits of the Cenomanian-Turonian boundary interval.
A first major conclusion is that fluvial aggradation in high-frequency transgressive-regressive sequences is coeval with the seaward-shift of the shoreline, in accordance with the genetic sequence stratigraphic model of Galloway (1989). Both the flatness of the depositional profile and the corresponding very low energy of the marine environment during the transgressions account for the blanket of red continental clays on top of marine facies in updip depositional sequences, which is then preserved under the marine transgressive surface of the next sequence.
A second major conclusion is that the high-frequency transgressive-regressive (T-R) sequences do not look like classical parasequences bounded by transgression surfaces. They usually exhibit a surface created by a sea-level fall within the regressive half-cycle. This is interpreted in the following way: regressions did not operate through a regular seaward-shift of the shoreline, but through stepped sea-level falls. The very low slope of the depositional ramp is thought to have enhanced the sequence stratigraphic record of such stepped regressions. Short-term, high-frequency sequences are organized into medium-frequency T-R sequences (seven in the Cenomanian) which show an overall aggrading and slowly retrograding pattern along the whole transect.
Comparisons with other basins show that medium-frequency sequences do not fit the third-order depositional sequences described elsewhere, casting doubts about a eustatic mechanism for their deposition.

Carnets Geol., vol. 15, no. 12, p. 137-172

Online since August 6, 2015


End of a modern geological myth: there are no rudists in Brazil! Paleobiogeographic implications
Bruno GRANIER & Dimas DIAS-BRITO

 | HTML  | PDF [1,631 KB]  | DOI: 10.4267/2042/56880

 Abstract:   Out of the few records of rudists from the Cretaceous strata of the South Atlantic coastal basins only two refer to Brazilian localities. However, petrographic analyses demonstrate that these shells should be assigned to Ostreids or to Pycnodontids rather than to Rudistids. More specifically, the domain considered herein, north of the Río Grande Rise - Walvis Ridge barrier, was part of the warm-water "tropical" realm, but it was not part of the Mesogean domain because both Rudistids and Orbitolinas are missing. In addition, the scarcity of corals leads us to ascribe the taphonomic assemblage to the Chloralgal facies. Neither generalized hypersalinity or extreme sea-water temperatures seem to account for these biotic peculiarities. Instead, our alternative hypothesis favors the driving role played by oceanic circulation in the dispersal of the benthic organisms.

Carnets Geol., vol. 15, no. 11, p. 123-136

Online since July 14, 2015


Facies, biostratigraphy, diagenesis, and depositional environments of Lower Cretaceous strata, Sierra San José section, Sonora (Mexico)
Jayagopal MADHAVARAJU, Robert W. SCOTT, Yong Il LEE, Kunjukrishnan Sathy BINCY, Carlos M. GONZÁLEZ-LEÓN & Sooriamuthu RAMASAMY

 | HTML  | PDF [1,401 KB]  | DOI: 10.4267/2042/56879

 Abstract:   We used petrofacies analysis, carbon, oxygen and strontium isotope data to interpret the isotopic variations in the carbonate rocks of the Mural Formation of Sonora (Sierra San José section), Mexico. The petrographic study reveals a range of lithofacies from wackestone to packstone. The analyzed limestones show significant negative δ18O values (-18.6 to -10.9 VPDB) and δ13C values ranging from negative to positive (-2.6 to +2.5‰ VPDB). The absence of correlation between δ13C and δ18O values suggests a primary marine origin for the δ13C values of limestones from the Sierra San José section. The limestones have large variations in 87Sr/86Sr values (0.707479 to 0.708790). Higher 87Sr/86Sr ratios in various levels of the studied section suggest that most of the sediments were derived from the Proterozoic basement of the Caborca block during Early Cretaceous time. A decrease in 87Sr/86Sr ratios at certain levels indicates an influx of lesser amounts of radiogenic Sr that could have been caused by contribution of sediments from the Triassic and Jurassic volcanic rocks.

Carnets Geol., vol. 15, no. 10, p. 103-122

Online since July 14, 2015


Cambrian fossils from the Barrandian area (Czech Republic) stored in the Musée d'Histoire Naturelle de Lille
Oldřich FATKA, Petr BUDIL, Catherine CRÔNIER, Jessie CUVELIER, Lukáš LAIBL, Thierry OUDOIRE, Marika POLECHOVÁ & Lucie FATKOVÁ

 | HTML  | PDF [1,415 KB]  | DOI: 10.4267/2042/56878

 Abstract:   A complete list of fossils originating from the Cambrian of the Barrandian area and housed in the Musée d'Histoire Naturelle de Lille is compiled. The collection includes two agnostids, ten trilobites, one brachiopod and one echinoderm species, all collected at ten outcrops in the Buchava Formation of the Skryje-Týřovice Basin and most probably also at two outcrops in the Jince Formation of the Příbram-Jince Basin. A large part of the material was collected by Prof. Charles Barrois and Dr. Louis Dollé (both University of Lille) during the excursion organised before the Ninth International Geological Congress in Vienna in 1903. Other, poorly documented specimens were purchased from the enterprise Krantz towards the end of the 19th century and in the first years of 20th century. The geographic position and stratigraphy of outcrops, from which the material originates, are briefly discussed.

Carnets Geol., vol. 15, no. 9, p. 89-101

Online since July 14, 2015


Lower Valanginian ammonite biostratigraphy in the Subbetic Domain (Betic Cordillera, southeastern Spain)
Miguel COMPANY & José M. TAVERA

 | HTML  | PDF [1,459 KB]  | DOI: 10.4267/2042/56745

 Abstract:   A new zonation for the lower Valanginian in the Betic Cordillera is presented. It is based on the study of 16 sections located near Caravaca and Cehegín (Region of Murcia). From bottom to top, the following interval zones, defined by the first appearance of the index-species, are distinguished:
● "Thurmanniceras" pertransiens Zone, which can be subdivided into two subzones, a lower "Th." pertransiens Subzone and an upper Vergoliceras salinarium Subzone. The latter is characterized by the disappearance of Olcostephanus drumensis and the appearance of Luppovella superba.
Neocomites neocomiensiformis Zone, also with two subzones, the Baronnites hirsutus Subzone below (characterized by the appearance of "Busnardoites" subcampylotoxus and Olcostephanus guebhardi) and the Valanginites dolioliformis Subzone above ("Busnardoites" campylotoxus is restricted to this subzone).
Karakaschiceras inostranzewi Zone, subdivided as well into two subzones, a lower Karakaschiceras inostranzewi Subzone and an upper Saynoceras contestanum Subzone.
The assemblages characterizing each of these biozones can be recognized throughout the Mediterranean region.

Carnets Geol., vol. 15, no. 8, p. 71-88

Online since June 11, 2015


Some encrusted hardgrounds from the Ordovician of Estonia (Baltica)
Olev VINN & Ursula TOOM

 | HTML  | PDF [344 KB]  | DOI: 10.4267/2042/56744

 Abstract:   The Ordovician hardground faunas of Estonia are not diverse. They include echinoderm holdfasts (i.e., eocrinoids and crinoids), edrioasteroids, bryozoans (both hemispherical trepostomes and stalked ptilodictyids) and cornulitids. The earliest hardground faunas appeared in the Dapingian (i.e., bryozoans and echinoderms). The Estonian hardground faunas are less diverse than the North American ones. North American hardgrounds seem to be more heavily encrusted than the Estonian ones. These differences may be due to the paleogeographic distances, different climates and different sedimentation environments of the paleocontinents.

Carnets Geol., vol. 15, no. 7, p. 63-70

Online since June 11, 2015


MayLib - a textfile-based bibliographic database for geosciences and a list of references on Devonian matters
Andreas MAY

 | HTML  | PDF [420 KB]  | DOI: 10.4267/2042/56481

 Abstract:  Scientists need to manage their own collections of bibliographic data as well as exchange these data easily with colleagues. One solution for this need is MayLib, a bibliographic database that runs on many different operating systems and does not require pre-installation of any software. MayLib is a very small, efficient and comprehensive JAVA program that handles references to publications in any Unicode-compatible language. It is user-friendly and not only contains the basic functions of a bibliographic database, but also has some advanced features. Using MayLib the author has been able to create a list of references, which contains 500 periodicals and 4206 literature references. Of these 4206 references 3191 deal with Devonian matters and 1594 references deal with corals.

Carnets Geol., vol. 15, no. 6, p. 59-62

Online since March 9, 2015


New faunistic data on the Pleistocene environmental evolution of the south-western edge of the Hyblean Plateau (SE Sicily)
Francesco SCIUTO, Antonietta ROSSO, Rossana SANFILIPPO & Rossana MANISCALCO

 | HTML  | PDF [2,810 KB]  | DOI: 10.4267/2042/56401

 Abstract:  Faunistic associations of the Lower Pleistocene sediments, out-cropping at Cartiera Molino along the true right bank of the Ippari River (Vittoria, SE Sicily), have been investigated. This study integrates data obtained from the analysis of ostracods, foraminifers, bryozoans and serpulids found within a six metre thick sedimentary section. This multiproxy approach allowed us to reconstruct the palaeoenvironmental evolution of this south-western sector of the Hyblean Plateau (Comiso-Vittoria area) from fluvially-influenced shallow marine settings, recorded in the lower portion of the succession, to progressively shallower, transitional and brackish environments, testified in mid levels, up to freshwater environments at the top of the section.

Carnets Geol., vol. 15, no. 5, p. 41-57

Online since February 28, 2015


A reassessment of the validity and affinities of Belemnites sulcatus Miller, 1826, Belemnopsis Edwards in Gray, 1849, and Belemnopsis Bayle, 1878
Simon F. MITCHELL

 | HTML  | PDF [172 KB]  | DOI: 10.4267/2042/56399

 Abstract:  A reinvestigation of the validity of the belemnite genus Belemnopsis Bayle is undertaken, together with a survey of the early history of the usage of the names Belemnites sulcatus, Belemnopsis Bayle and Belemnopsis Edwards. Belemnites sulcatus Miller has been variously equated with either Belemnites apiciconus Blainville or with the group of belemnites including Belemnites Altdorfensis Blainville and B. Beaumontianus Orbigny. Riegraf (and not Phillips) subsequently designated a lectotype which may be valid and, in case it is not, is validated here. The species concept for Belemnites sulcatus, as based on this lectotype, places it in the genus Holcobeloides Gustomesov. Belemnopsis Edwards has date priority over Belemnopsis Bayle, but must be interpreted as an "incorrect original spelling" and, therefore, does not enter into homonymy according to the ICZN; Belemnopsis Bayle is thus a valid genus. Douvillé subsequently nominated Belemnites sulcatus, which was figured as Belemnopsis sulcata by Bayle, and therefore is a valid designation because this species is amongst the original species included in Belemnopsis by Bayle. One of Bayle's figures of Belemnopsis sulcata agrees with Belemnites apiciconus Blainville, but does not agree with Belemnites sulcatus as defined by its lectotype; as such this is a case of misidentified type species. Belemnites apiciconus Blainville, the species involved in the misidentification, is therefore designated type species of Belemnopsis Bayle here and validated by citing the ICZN. The actions taken here maintain nomenclature at the genus, family and suborder level in respect to the names Belemnopsis and Belemnosis and serve to stabilize the complicated nomenclature issues related to these taxa.

Carnets Geol., vol. 15, no. 4, p. 31-39

Online since February 28, 2015


Earliest Aptian Caprinidae (Bivalvia, Hippuritida) from Lebanon
Jean-Pierre MASSE, Sibelle MAKSOUD, Mukerrem FENERCI-MASSE, Bruno GRANIER & Dany AZAR

 | HTML  | PDF [1,585 KB]  | DOI: 10.4267/2042/56397

 Abstract:  The presence in Lebanon of Offneria murgensis and Offneria nicolinae, two characteristic components of the Early Aptian Arabo-African rudist faunas, fills a distributional gap of the corresponding assemblage between the Arabic and African occurrences, on the one hand, and the Apulian occurrences, on the other hand. This fauna bears out the palaeogeographic placement of Lebanon on the southern Mediterranean Tethys margin established by palaeostructural reconstructions. The associated micropaleontological elements suggest an earliest Aptian age (early Bedoulian) for the Offneria murgensis - O. nicolinae assemblage found in the "Falaise de Blanche" stratigraphic interval, instead of a late Early Aptian age as proposed for most of the peri-Adriatic and Middle East occurrences recognized so far. These caprinid specimens are characterized by relatively modest sizes, moreover other rudists commonly part of the assemblage are lacking. The dominance of caprinids in the study area suggests a distal platform setting, i.e., close proximity to the platform edge.

Carnets Geol., vol. 15, no. 3, p. 21-30

Online since February 15, 2015


Simple and practical techniques to manage small databases, illustrated by a case study: bibliographic data from the "Fossil Cnidaria & Porifera" newsletter (1972-2010)
Katarzyna ZALECKA, Tomasz WRZOŁEK & Bruno GRANIER

 | HTML  | PDF [342 KB]  | DOI: 10.4267/2042/56249

 Abstract:  Small databases, i.e., with less than 15,000 entries, are sometimes handled using inappropriate, complex, and often expensive data management systems. We present and briefly discuss a few types of proprietary and open-source, relational and non-relational, server-based versus portable databases and specific tools to handle the latter. With a collection of nearly 7,000 bibliographic notes during its 40-year history "Fossil Cnidaria & Porifera (FC&P)", the newsletter of the "International Association for Study of Fossil Cnidaria and Porifera", was chosen as a case study. The analysis of the temporal trends in the FC&P bibliographic database shows a decrease over the years in the number of publications effectively reported in FC&P. Almost all relevant papers for the decade 1981-1990 are reported, but this good coverage ratio falls down to less than 50% after 2000; accordingly, the concern about the data representativeness is addressed in our interpretation. Besides the classical database management systems and spreadsheet software, which were originally used with the FC&P case study, we present two discrete, open-source, flat and portable options where data can be displayed using any widely available Internet browser, and that are suitable to handle most small databases (XML or JS files) as documented herein.

Carnets Geol., vol. 15, no. 2, p. 13-19

Online since January 14, 2015


Lower Aptian ammonites of the Sierra de Parras, Coahuila State, northern Mexico
José R. OVANDO-FIGUEROA, Josep A. MORENO-BEDMAR Gabriel, CHÁVEZ-CABELLO & Keith P. MINOR

 | HTML  | PDF [2,356 KB]  | DOI: 10.4267/2042/56250

 Abstract:  We report an interesting Aptian ammonite record from the La Peña Formation in the Sierra de Parras, Coahuila State. This assemblage is analyzed from a paleoecological perspective. It contains the first reported occurrence of a macroconch of Dufrenoyia from Mexico, and the largest known specimen of  'Gargasiceras' adkinsi. Such an assemblage yielding large ammonites is unusual in deposits of this age in Mexico. To properly document this ammonite record, we review 'Gargasiceras' adkinsi, formerly misidentified as Rhytidoplites robertsi, and allied taxa. From our analysis, we conclude that 'Gargasiceras' adkinsi exhibits strong intraspecific variability. We also analyze in detail the differences that exist between 'Gargasiceras' adkinsi and Rhytidoplites robertsi, and emend the concept of the genus Rhytidoplites. These revisions are important from a biostratigraphic point of view since 'Gargasiceras' adkinsi is an index species for the lower Aptian ammonite zonation of Mexico.

Carnets Geol., vol. 15, no. 1, p. 1-11

Online since January 14, 2015


up2  

2014 (vol. 14)

In memoriam of my colleague and friend Guy Tronchetti (1938-2014)
Michel MOULLADE

    | HTML  | PDF [112 KB]  | DOI: 10.4267/2042/56047

Guy_TronchettiThe chief editor of a prestigious scientific journal, who is about to publish a major article of which Guy is one of the lead authors, replied to the news of his passing: "I am very sorry to hear about that. I have known Guy Tronchetti from publications, for a long time. It is really sad." This quote and Googling his name show that, according to his publications, some of them very recent, Guy was still both at the cutting edges of research and a scientist at an international level. His great modesty did not allow people to necessarily acknowledge this, especially those who did not attempt to overcome such an obstacle. (...) 

Carnets Geol., vol. 14, Obituary notice, p. 483-487

Manuscript online since December 24, 2014


Significance of partial leaching in calcareous ooids: The case study of Hauterivian oolites in Switzerland
Bruno GRANIER, Vincent BARBIN & Jean CHAROLLAIS

 | HTML  | PDF [1,312 KB]  | DOI: 10.4267/2042/56045

 Abstract:  In the Canton of Vaud (Switzerland), two Hauterivian oolitic units were penetrated by a borehole. In both units, the ooids are partly leached. More specifically, the ooid cortices were partly leached and some ooid nuclei appear suspended in the middle of cortical moldic cavities created by leaching, rather than having fallen to the bottom of these cavities before the final cementation take place. We demonstrate that these ooids were originally calcitic, not aragonitic, not "two-phase" nor "bimineral". This leaching is not an early diagenetic feature related to subaerial exposure, but a late diagenetic feature, possibly related to the migration of acidic pore waters, brought about by Alpine tectonics and/or karstification.

Carnets Geol., vol. 14, no. 22, p. 471-481

Published online in final form (pdf) on December 24, 2014


Borings and etchings in the Upper Bathonian-Lower Callovian oolite of the Paris Basin (France)
Bruno GRANIER

 | HTML  | PDF [1,250 KB]  | DOI: 10.4267/2042/56043

 Abstract:  The oolite of the "Dalle Nacrée" Formation in the Paris Basin is made of marine calcareous ooids with, from base to top, radial (and therefore likely to have been calcite), concentric and micritic fabrics, each corresponding to a discrete stratigraphic unit. Several hardgrounds and oolitic pebble-cobble layers in the succession are encrusted and bored. Three main types of boring have been identified ranging in sizes from some tens of µm (sponge borings) to centimeters (bivalve borings), with an intermediate category (worm borings). Some worm borings have rough walls, where early marine fibrous cement is less corroded than the cortices of cemented ooids. The key to understanding this differential dissolution could be related to organic matter, present within the ooid cortices but lacking in the fibrous cement. Polychaete worms that use chemical means (enzymes or acids) to bore are probably responsible for these peculiar borings. A secondary conclusion is that partly or fully leached ooid cortices do not necessarily indicate an original aragonitic mineralogy of the dissolved parts.

Carnets Geol., vol. 14, no. 21, p. 461-469

Published online in final form (pdf) on December 24, 2014


Devonian Phillipsastreid tetracorals of the genus Rozkowskaella from the Holy Cross Mountains, Poland
Tomasz WRZOŁEK

 | HTML  | PDF [9,340 KB]  | DOI: 10.4267/2042/56041

 Abstract:  Solitary or weakly colonial Phillipsastreid tetracorals of the Upper Frasnian of Holy Cross Mountains, Poland, with triangular to oval shape of transverse-section and tendency towards reduction of the horseshoe dissepiments, are included here in the genus Rozkowskaella, with Rozkowskaella sandaliformis, R. cf. sandaliformis and Rozkowskaella sp.

Carnets Geol., vol. 14, no. 20, p. 439-459

Published online in final form (pdf) on December 24, 2014


Two new species of Early Pleistocene marine ostracods from Southeast Sicily
Francesco SCIUTO

 | HTML  | PDF [1,769 KB]  | DOI: 10.4267/2042/56039

 Abstract:  Two fossil species of Ostracoda belonging to the genera Urocythereis Ruggieri, 1950, and Semicytherura Wagner, 1957, discovered in the Lower Pleistocene shallow marine sandy-silty sediments outcropping at "Cartiera Molino" (F. 276, IV NO, Vittoria, Southeast Sicily) are described and figured.

Carnets Geol., vol. 14, no. 19, p. 429-437

Published online in final form (pdf) on December 24, 2014


Revision of "Falaise de Blanche" (Lower Cretaceous) in Lebanon, with the definition of a Jezzinian Regional Stage
Sibelle MAKSOUD, Bruno GRANIER, Dany AZAR, Raymond GÈZE, Jean-Claude PAICHELER & Josep A. MORENO-BEDMAR

 | HTML  | PDF [4,404 KB]  | DOI: 10.4267/2042/54359

 Abstract:  The "Falaise de Blanche" is a prominent cliff, consisting mostly of Lower Cretaceous limestones that extends as linear outcrops over most of the Lebanese territory and provides geologists a remarkable reference for stratigraphic studies. However, until now, this unit was lacking a clear definition. We introduce herein the Jezzinian Regional Stage, the type-locality of which is at Jezzine. It equates as an unconformity-bounded unit and, per definition, it is framed by two discontinuities. Because we identified an additional, median sequence-boundary, poorly-expressed in the type-section but better at Aazour, only 4.5 km westward of Jezzine, the new regional stage implicitly spans two sequences. The lithostratigraphic framework being properly redefined, we were able to investigate time-constrained micropaleontological assemblages, consisting mostly of benthic foraminifers and calcareous algae. Typically Southern Tethysian, these assemblages contribute to high-resolution, holostratigraphic correlations with the Persian Gulf area, on the eastern part of the Arabian Plate. The Jezzinian interval correlates with the upper part of the Kharaibian Regional Stage (also known as "Thamama II" reservoir unit in the oil industry). In turn, the Jezzinian is indirectly correlated with the Northern Tethysian Urgonian stratigraphic units where it corresponds to a rather short interval encompassing the standard Barremian - Bedoulian stage boundary. Locally the upper discontinuity is associated to a significant intra-Bedoulian hiatus. The macrofossil assemblages found in the Jezzinian (echinids) and above it (ammonites) support, or at least do not contradict, our micropaleontological dating.

Carnets Geol., vol. 14, no. 18, p. 401-427

Published online in final form (pdf) on November 14, 2014


The genera Subgrossouvria Spath and Orionoides Spath (Ammonitina, Perisphinctidae) from the Leckenbyi Horizon (Upper Callovian, Athleta Zone) of Montreuil-Bellay (Maine-et-Loire, France)
Alain BONNOT, Pierre-Yves BOURSICOT & Patrice FERCHAUD

 | HTML  | PDF [11,574 KB]  | DOI: 10.4267/2042/54363

 Abstract:  In the Montreuil-Bellay area (Maine-et-Loire, France), the lowermost bed of the Upper Callovian (Leckenbyi Horizon) contains a very abundant ammonite fauna (N=3275). The Family Perisphinctidae is represented by Choffatia isabellae Bonnot et al., the genus Pseudopeltoceras Spath, the genus Subgrossouvria Spath, which includes S. famula (Bean in Spath) and S. crassa Gérard & Contaut, and the genus Orionoides Spath, which comprises O. indicus Spath. Thanks to the abundance and quality of the material, it was possible to describe and figure macroconchs and microconchs of these three species, including adult specimens with preserved peristome. The stratigraphical ranges of these taxa are also specified and their potential descendants can be considered. These species are unknown in the uppermost Middle Callovian, and we assume that they colonized the northwestern part of the European platform via the southern margin of the Tethys, as did Peltoceras marysae Bonnot et al. and Choffatia isabellae Bonnot et al.

Carnets Geol., vol. 14, no. 17, p. 351-399

Published online in final form (pdf) on November 14, 2014


Nannofossils and foraminifera from the Salamanca Formation (Paleocene) in Punta Peligro Norte (Chubut, Argentina)
Margarita SIMEONI

 | HTML  | PDF [1,700 KB]  | DOI: 10.4267/2042/54361

 Abstract:  An assemblage of nannofossils from the Salamanca Formation is reported for the first time from the Punta Peligro Norte locality in the San Jorge Gulf Basin, Argentina. Several recognized nannofossils have a stratigraphic distribution within the lower Danian. The assemblage of nannofossils and associated foraminifera is here discussed taking into account biostratigraphic and paleoecological aspects.

Carnets Geol., vol. 14, no. 16, p. 343-349

Published online in final form (pdf) on November 14, 2014


Ostracodes from the Upper Cretaceous deposits of the Potiguar Basin, northeastern Brazil: taxonomy, paleoecology and paleobiogeography. Part 2: Santonian-Campanian
Enelise K. PIOVESAN, Maria Cristina CABRAL, Jean-Paul COLIN, Gerson FAUTH & Cristianini TRESCASTRO BERGUE

 | HTML  | PDF [8,480 KB]  | DOI: 10.4267/2042/54151

 Abstract:  Sixty-four Ostracoda taxa were recorded from the Santonian–Campanian of Potiguar Basin, northeastern Brazil. The following new species were described: Triebelina anterotuberculata, Triebelina obliquocostata, Cophinia ovalis, Fossocytheridea potiguarensis, Ovocytheridea anterocompressa, Ovocytheridea triangularis, Perissocytheridea jandairensis, Semicytherura musacchioi and Protocosta babinoti. The faunal association indicates predominantly shallow marine environments, intercalated with typically mixohaline levels. These species are mostly endemic, although the presence of six species common to West and North Africa shows that migration was still possible by the end of the Cretaceous.

Carnets Geol., vol. 14, no. 15, p. 315-341

Published online in final form (pdf) on October 14, 2014


Temporal and latitudinal trends in the biodiversity of European Atlantic Cenozoic gastropod (Mollusca) faunas. A base for the history of biogeographic provinces
Pierre LOZOUET

 | HTML  | PDF [2,328 KB]  | DOI: 10.4267/2042/54150

 Abstract:  A general overview of the biodiversity of the marine fauna during the Tertiary period is developed in the context of the biogeographical evolution of the European realm. This study combines a reappraisal of the literature with a unique first-hand source of data on the richest marine group (the gastropods) from over a 25 million year period (Early Oligocene to Late Miocene). In total the French deposits have yielded more than 10,000 species from the Eocene to the Upper Miocene. Evidence of significant bias in the fossil record is pointed out for the Palaeocene (Danian) and Upper Eocene (Priabonian). For the period considered (Palaeocene to Late Miocene, ca 50 million years) the second highest diversity is reported in the Late Oligocene. This study reveals also the importance of pre-Miocene extinctions of genera. The Oligocene was when the latitudinal differentiation of the faunas was greatest. The local generic gastropod richness ranges from 59 (Rupelian of Belgium) to 494 (Chattian of Aquitaine). A clear trend towards homogenization appears in the Late Oligocene which leads to the development of a vast biogeographical region named Euro-West Africa. This faunal evolutionary pattern has never been demonstrated before and is a novel feature of the biogeography of the Eastern-Atlantic region.

Carnets Geol., vol. 14, no. 14, p. 273-314

Published online in final form (pdf) on October 14, 2014


Origin of the Tethyan Hemihoplitidae tested with cladistics (Ancyloceratina, Ammonoidea, Early Cretaceous): an immigration event?
Didier BERT & Stéphane BERSAC

 | HTML  | PDF [612 KB]  | DOI: 10.4267/2042/54149

 Abstract:  The Late Barremian Hemihoplitidae (Ancyloceratina, Ammonoidea) are widely known in the northern Tethyan Margin and the Essaouira-Agadir Basin (Morocco). Their rapid evolution and diversification make them one of the key groups for that period, but their origin remains poorly known and several competing hypotheses have been published. These hypotheses are tested here with cladistic analysis in order to reject those receiving the least support and discuss those well supported. The analysis discards the Crioceratitidae, Emericiceratidae (Emericiceras and Honnoratia) and Toxancyloceras as stem-groups of the Hemihoplitidae (Gassendiceras). The Toxancyloceras appear instead to be a sister-taxon of the Moutoniceras, so we propose the latter to be classified with the Ancyloceratidae rather than with the Heteroceratidae. The best supported hypothesis assumes that the Hemihoplitidae first appeared suddenly in the Essaouira-Agadir Basin at the end of the Early Barremian from small populations of Boreal Paracrioceras. These latter could have migrated southward episodically before invading the northern Tethyan margin at the beginning of the Late Barremian. As a consequence, the Paracrioceratidae fam. nov. is proposed to include the Boreal groups Fissicostaticeras / Paracrioceras / Parancyloceras, and Gassendiceras essaouirae sp. nov. is proposed as a new name for the Moroccan endemic "Barrancyloceras" maghrebiense sensu Company et al., 2008, non Immel, 1978.

Carnets Geol., vol. 14, no. 13, p. 255-272

Published online in final form (pdf) on October 14, 2014


Ostracodes from the Upper Cretaceous deposits of the Potiguar Basin, northeastern Brazil: taxonomy, paleoecology and paleobiogeography. Part 1: Turonian
Enelise K. PIOVESAN, Maria Cristina CABRAL, Jean-Paul COLIN, Gerson FAUTH & Cristianini TRESCASTRO BERGUE

 | HTML  | PDF [7,882 KB]  | DOI: 10.4267/2042/54003

 Abstract:  This paper describes thirteen new species and two new genera of marine and brackish water ostracodes from the Turonian deposits of Potiguar Basin, NE Brazil, among a total of 53 taxa. The new species include Cophinia grekoffi, Fossocytheridea tiberti, Haughtonileberis dinglei, Hemicytherura viviersae, Jandairella obesa (new genus and species), Loxocorniculum? narendrai, Ovocytheridea posteroprojecta, O. reymenti, Perissocytheridea caudata, P. mossoroensis, Potiguarella grosdidieri (new genus and species), P. coimbrai and Procytherura ballentae. The diversity and dominance indexes vary according to the paleoenvironment. Three assemblages were identified: a predominantly mixohaline fauna in the basal part of the section, followed by a diversified shallow marine fauna and, in the upper part, a marine and brackish water ostracode fauna. Most of the recorded species are endemic. Eight species are common to Northwest and North Africa, indicating a faunal link during the Turonian. The study of the Turonian faunas of the Potiguar Basin represents a significant improvement to understand the dynamic evolution of the Brazilian basins and the paleobiogeographical relationship with other regions.

Carnets Geol., vol. 14, no. 12, p. 211-252

Published online in final form (pdf) on July 3, 2014

 Erratum:  The table rows of Appendix 2 (i.e., "Distribution of the ostracode species, with their abundances") should have included numbers.

Format [PDF 78 KB]

Online since July 27, 2014


First record of lowermost Cretaceous shallow-water limestones in the basement of the Transylvanian Depression (Romania)
Ioan I. BUCUR, Adriana PĂCURARIU, Emanoil SĂSĂRAN, Sorin FILIPESCU & Rodica FILIPESCU

 | HTML  | PDF [1,655 KB]  | DOI: 10.4267/2042/54001

 Abstract:  Triassic, Upper Jurassic and upper Lower Cretaceous sedimentary formations were previously studied from the Transylvanian Depression basement, but the presence of lowermost Cretaceous (Berriasian-Valanginian) has not been confirmed paleontologically. The carbonate sequence cored from a borehole drilled in the central part of the Transylvanian Depression yields microfossil assemblages dominated by benthic foraminifera. These new data unequivocally document the presence of characteristic Berriasian-Valanginian taxa in these deposits.

Carnets Geol., vol. 14, no. 11, p. 199-210

Published online in final form (pdf) on July 3, 2014

 Erratum:  The table rows of Appendix 2 (i.e., "Distribution of the ostracode species, with their abundances") should have included numbers.

Format [PDF 78 KB]

Online since July 27, 2014


A new type of entombment of Peronopsis (Agnostida) in a hyolithid conch
Oldřich FATKA & Vladislav KOZÁK

 | HTML  | PDF [592 KB]  | DOI: 10.4267/2042/54000

 Abstract:  An enrolled exoskeleton of the holaspid specimen of a tiny agnostid Peronopsis integra (Beyrich, 1845) entombed inside a conch of the hyolithid ?Buchavalites sp. is described from the middle Cambrian (Drumian) Jince Formation of the Příbram-Jince Basin (Czech Republic). The agnostid is associated with an ichnofossil of the feeding trace classified as Arachnostega-type behaviour. The enrolled attitude of the agnostid exoskeleton suggests that the specimen is a carcass rather than moult. Either the storm disturbance and/or well-protected source of food hypotheses could explain the entombed agnostid. This additional example supports a benthic mode of life in the agnostid P. integra. The studied association of feeding tunnels of an unknown Arachnostega-strategist and Peronopsis preserved inside a hyolithid conch is a case of "frozen" behaviour.

Carnets Geol., vol. 14, no. 10, p. 191-198

Published online in final form (pdf) on July 3, 2014


The Cretaceous-Paleogene boundary and its 405-kyr eccentricity cycle phase: a new constraint on radiometric dating and astrochronology
Michel HENNEBERT

 | HTML  | PDF [547 KB]  | DOI: 10.4267/2042/53981

 Abstract:  Radiometric dating and astrochronologic dating still suffer discrepancies without knowing which one gives the most reliable results. A new tool is proposed to constrain both the approaches. The phase of the 405-kyr signal with respect to the Cretaceous - Paleogene boundary event has been determined in the Aïn Settara section (Kalaat Senan, central Tunisia). We use this phase value (Option 2), as well as an average of phase values obtained from the literature (Option 1), to examine the relationship linking both the radiometric (absolute) age assigned to the K-Pg boundary and the Cenozoic average-value of the ~405-kyr eccentricity period. A new useful constraint emerges: to any absolute age assumed for the K-Pg boundary corresponds a value of the mean Cenozoic 405-kyr period, and vice versa.
Supposing a K-Pg boundary radiometric age in the vicinity of 66.0 Ma, then the number of entire cycles (comprised between two minima of the 405-kyr eccentricity signal) within the Cenozoic Period could only be equal to 163. When adding to this figure the parts of the cycles preceding and following these 163 entire cycles the total duration of the Cenozoic Era becomes equal to 163.168 cycles (Option 1) or 163.081 cycles (Option 2).
We propose to grant a special interest to the determination of the 405-kyr cycle phase at stratigraphically well documented levels, particularly those that correspond to world-wide, sudden and catastrophic events, that are well located in time by reliable radiometric dates.

Carnets Geol., vol. 14, no. 9, p. 173-189

Published online in final form (pdf) on June 19, 2014


Novocrania turbinata synonym of N. anomala
Christian C. EMIG

 | HTML  | PDF [2,664 KB]  | DOI: 10.4267/2042/53979

 Abstract:  Anomia turbinata, or conical Anomia (= Novocrania turbinata), was described by Poli (1795) in the bathyal environment off the coast of the Kingdom of the Two Sicilies, Patella anomala Müller, 1776 (= N. anomala) being considered a synonym. The history of this species, commonly considered as the Mediterranean form of N. anomala, will be described. Recently, several authors have described N. turbinata as a valid species on the basis of shell variations, as compared to N. anomala. After analysis of the taxonomic validity of these characters, both species are considered as synonymous. That is supported by their occurrence in various localities, mainly in the continental shelf. Their synonymy has been corroborated by molecular analyses and is discussed with reference to the characteristics of the Mediterranean basins and their history since the Miocene.

Carnets Geol., vol. 14, no. 8, p. 159-171

Published online in final form (pdf) on June 19, 2014


Heydrichia (?) poignantii, sp. nov. (Sporolithaceae, Sporolithales, Rhodophyta), a 100 million year old fossil coralline red alga from north-eastern Brazil, and a new Hauterivian record of Sporolithon from Switzerland
William J. WOELKERLING, Bruno GRANIER & Dimas DIAS-BRITO

 | HTML  | PDF [4,062 KB]  | DOI: 10.4267/2042/53736

 Abstract:  Fossil specimens of Heydrichia (?) poignantii, sp. nov. (Sporolithaceae, Sporolithales, Rhodophyta), representing the first confirmation of the genus in the fossil record, were discovered in thin sections of Albian limestones from the Riachuelo Formation, Sergipe Basin, and in thin sections of Albian - Cenomanian limestones from the Ponta do Mel Formation, Potiguar Basin in north-eastern Brazil. A detailed morphological-anatomical account of the species is provided, and its placement in Heydrichia is discussed in relation to current classification proposals. Comparisons with the four other known species of the genus, all non-fossil, show that H. poignantii is the only known species of Heydrichia in which thalli are encrusting to sparsely warty to horizontally layered with overlapping lamellate branches that commonly appear variously curved or arched, and in which thalli have sporangial complexes that become buried in the thallus. The evolutionary history of Heydrichia remains uncertain, but available data suggest that the genus may have diverged from the sporolithacean genus Sporolithon, known as early as Hauterivian times (c. 129.4-132.9 ± 1 Ma) from Spain (and newly reported here from Switzerland), or it may have arisen from a graticulacean alga such as Graticula, dating from mid-Silurian times (c. 427-435 Ma). Current data also suggest that Heydrichia is more likely to have arrived in Brazil from Central Atlantic waters than from higher latitude South Atlantic waters. This implies that currently living species in southern Africa probably arose later from ancestors further equatorward in the South Atlantic, although confirming studies are needed. All non-fossil species of Heydrichia are known only from the southern hemisphere.

Carnets Geol., vol. 14, no. 7, p. 139-158

Published online in final form (pdf) on May 8, 2014


A negative carbon isotope excursion within the Dufrenoyia furcata Zone: proposal for a new episode for chemo-stratigraphic correlation in the Aptian
Fernando NUÑEZ-USECHE, Josep Anton MORENO-BEDMAR, Miguel COMPANY & Ricardo BARRAGÁN

 | HTML  | PDF [500 KB]  | DOI: 10.4267/2042/53734

 Abstract:  In this work we discuss a proposed updated division of the C7 isotope segment of Menegatti et al. (1998). The new standard division of the segment C7 is based on a revision of published Barremian-Aptian carbon isotope curves from stratigraphic sections of the Prebetic Domain in Spain. It includes four distinct isotopic subunits labeled C7a to C7d, with a characteristic negative carbon isotope excursion at the base of the segment and which correlates with the Dufrenoyia furcata ammonite Zone. The negative excursion is recognized on a regional extent, and the term Intra-Furcata Negative Excursion (IFNE) is proposed to identify it. We provide possible sites correlatable with the IFNE in both the Old and New worlds, which suggest its potential use as an even global chemostratigraphic marker for the Aptian record.

Carnets Geol., vol. 14, no. 6, p. 129-137

Online since May 8, 2014


The Albian Stage in its type area, the Aube (France): a synthesis in a global sedimentary context
Francis AMÉDRO & Bertrand MATRION

 | HTML  | PDF [2,810 KB]  | DOI: 10.4267/2042/53732

 Abstract:  The Aube department is the type locality of the Albian stage created by d'Orbigny (1842). Two formations are recognised in the clay facies (the "Gault" auct.) of the stratotype, the Argiles tégulines de Courcelles (82 m), which is overlain by the Marnes de Brienne (43 m). The boundary between the two formations is defined at the top of an indurated bed (hardground L'Étape) that is readily identifiable, both in the field, and from boreholes. The type area of the Albian stage is of great interest because of the size of the clay facies (more than 120 m) unique in the Anglo-Paris basin. Today, 82 % of the lithological succession is documented accurately from 16 outcrops. In two intervals of respectively 33 m and 28.50 m thick, composite sections are made of overlapping sections which are correlated in the field with the help of lithological marker beds. Six successive facies are described: in the Argiles tégulines de Courcelles and from bottom to top: 1 - phosphatic nodules bed; 2 - silty clays; 3 - clays and limestone beds; in the Marnes de Brienne: 4 - clay marls; 5 - gaize; 6 - clay marls. On a smaller scale, a decimetre to metre-scale rhythmicity can be identified in the sedimentation. This is reflected in the Argiles tégulines de Courcelles by pluri-decimetric cycles that start with a silty level and are bounded at the top by a bored surface. In the Marnes de Brienne, the metric cycles (except for the gaize where they are decimetric) exhibit alternating dark grey clay marl and a pale grey marl that herald the rhythmic chalks of the Cenomanian. Individual couplets probably represent the precession cycles (20 kyr). On the other hand, 13 lithoevents as phosphatic nodules beds, hardgrounds, glauconitic and sandy beds and ecoevents characterised by the brief abundance of some fossils. These marker beds are very useful for fine correlations across the basin. A comparison is proposed between sandy units of Yonne and clay facies of Aube. The continuity of several phosphatic nodules beds is shown from Yonne in the South West to Aube and Perthois in the North East, that is a distance exceeding 130 km. These marker beds are interpreted as Flooding Surfaces of 3rd-order cycles. Finally, a detailed study of the lithology, complemented with the analysis of the ammonite and inoceramid faunas, is used for a depositional sequence interpretation. As a result, eight sequences are identified in the upper half of the Argiles tégulines de Courcelles and in the Marnes de Brienne in the type area of the Albian stage, including two new sequences indexed AL 5a and AL 6a.

Carnets Geol., vol. 14, no. 5, p. 69-128

Online since May 8, 2014


Paleocene larger foraminifera from the Yucatán Peninsula (SE Mexico)
Vicent VICEDO, José Antonio BERLANGA & Josep SERRA-KIEL

 | HTML  | PDF [11,544 KB]  | DOI: 10.4267/2042/53527

 Abstract:  The larger foraminifera found in the material from the Chichen Itzá Formation of Campeche (SE Mexico) were studied in detail. The architectural analyses allow the description of four new species and a new genus, namely, two agglutinated conical foraminifera, Coskinolina yucatanensis n.sp. and Pseudofallotella drobneae n. gen. n.sp., one new alveolinid, Borelis hottingeri n.sp., and one new rotaliid, Dictyoconoides boneti n.sp. The larger foraminifera of the Chichen Itzá Formation are distributed across two different associations: one includes Pseudofallotella drobneae, Neotaberina sp., Rhabdorites sp., Borelis hottingeri, Dictyoconoides boneti, Kathina sp., Miscellaneidae, Ranikothalia soldadensis and Hexagonocyclina cristensis, while the other assemblage is composed of Coskinolina yucatensis, Fallotella causae, Rhabdorites sp., Borelis floridanus and Cincoriola cf. ovoidea. Some of these genera, including Neotaberina and Dictyoconoides, are cited in the Caribbean paleobioprovince for the first time in this paper. The first association is dated as Thanetian (SBZ 3? to SBZ 4) by the presence of Ranikothalia soldadensis. Though the age of the second association remains uncertain, a similar age has been inferred.

Carnets Geol., vol. 14, no. 4, p. 41-68

Online since March 17, 2014


Acanthocythereis colini nomen novum for A. reticulata Sciuto, 2014
Francesco SCIUTO

 | HTML  | PDF [27 KB]  | DOI: 10.4267/2042/53523

 Excerpt:  In Sciuto (2014), a new species, Acanthocythereis reticulata, was described from the Upper Pliocene sediments of NE Sicily and belonging to the Family Trachyleberididae Sylvester-Bradley, 1948.. (...)

Carnets Geol., vol. 14, no. 3, p. 39

Online since February 28, 2014


A Cretaceous chronostratigraphic database: construction and applications
Robert W. SCOTT

 | HTML  | PDF [1,718 KB]  | DOI: 10.4267/2042/53522

 Abstract:  Timing and rates of tectonic events, evolutionary processes, and oceanographic and paleoclimatic changes must be based on high-precision numerical age calibration of stages defined in Global Stratotype and Section Points (GSSPs). The Cretaceous Chronostratigraphic Database (CRETCSDB3) is an objective, testable database that calibrates select Cretaceous events and enables high-resolution chronostratigraphic correlations.
CRETCSDB3 is a compilation of more than 3500 taxa and marker beds in nearly 300 published sections calibrated to a mega-annum (Ma) scale. The database spans the Jurassic/Cretaceous and the Cretaceous/Paleogene boundaries. Construction of CRETCSDB3 began by plotting bioevents in the Kalaat Senan, Tunisia, Cenomanian-Turonian section to the 1989 time scale. The sedimentology, sequence stratigraphy, and biostratigraphy of this section were precisely documented and stage boundaries defined biostratigraphically. Additional sections with radiometrically dated beds were graphed to constrain the accuracy of the numerical scale. Ranges of first and last occurrences are calibrated to mega-annums of Cretaceous stages defined by GSSPs or reference sections. This database serves as a look-up table for interpolation and age calibration of other stratigraphic sections. The age ranges of some taxa and marker beds are preliminary and may be extended as new sections are added to the database.
CRETCSDB3 tested the numeric age calibration of the Albian/Cenomanian boundary. This boundary in North Texas accurately correlates with the GSSP in France by ammonites, planktic foraminifers and dinoflagellates. This stage boundary in North Texas correlates with the 97.88±0.69 Ma Clay Spur Bentonite in Wyoming by sequence stratigraphy and cosmopolitan dinoflagellates. The inconsistency between this age and the current 100.5 Ma date of the 2012 Geologic Time Scale remains to be evaluated independently.

Carnets Geol., vol. 14, no. 2, p. 15-37

Online since February 28, 2014


Ostracods of the Upper Pliocene - Pleistocene Punta Mazza succession (NE Sicily) with special focus on the Family Trachyleberididae Sylvester-Bradley, 1948, and description of a new species
Francesco SCIUTO

 | HTML  | PDF [1,980 KB]  | DOI: 10.4267/2042/53172

 Abstract:  The ostracod associations of the Upper Pliocene-Pleistocene sedimentary succession out-cropping at Punta Mazza (Milazzo, Sicily NE) have been investigated. The ostracod fauna is often well-preserved and well-diversified: there 42 species belonging to 24 genera have been found. The association consists almost exclusively of bathyal taxa such as Bythocypris obtusata (Sars), B. bosquetiana (Brady), Henryhowella ex H. profunda Bonaduce et al. group, Quasibuntonia radiatopora (Seguenza), Retibythere (Bathybythere) scaberrima Brady, Pseudocythere caudata Sars and Bythocythere mylaensis Sciuto. Also, the Krithe group is well-represented with Krithe compressa (Seguenza) and K. pernoides (Bornemann). Further taxa such as Cytheropteron testudo Sars are rare. Almost all species, especially those belonging to Trachyleberididae Sylvester-Bradley are described, illustrated and commented on, including a new species, Acanthocythereis reticulata n.sp., found in the lower part of the section in Upper Pliocene sediment, is proposed as new. Finally, a specimen belonging to the genus Quasibuntonia Ruggieri is currently given in open nomenclature.

Carnets Geol., vol. 14, no. 1, p. 1-13

Online since January 25, 2014


up2  

2013 (vol. 13) 

Article 9 [2013]: Silurian cornulitids of Estonia (Baltica), by Olev VINN & Mark A. WILSON.-
Format [HTML] or [PDF 1,050 KB]
Reference: [CG2013_A09]
DOI: 10.4267/2042/53034
Lang.: 

CG2013_A09_thumb Abstract:  Seven species of cornulitids are systematically described from the Silurian of Saaremaa and Hiiumaa islands, Estonia. There are three species of cornulitids in the Rhuddanian, three in the Sheinwoodian, single species in the Gorstian and Ludfordian, and three species in the Pridoli. Cornulitids have a facies range from pelletal limestones of shoal environments to deeper ramp marls. Endobiotic cornulitid symbionts occur in stromatoporoids found in shoal and open shelf zones. Gregarious aggregates are restricted to the limestones of the open shelf zone possibly because of higher nutrient levels in open shelf zone waters as compared to those of the deeper ramp. Unattached free forms are especially common in offshore deeper ramp marls presumably due to their adaption to life on a soft bottom. Solitary attached forms occur in all facies zones where cornulitids are present. Because the life modes of cornulitids are closely associated with particular facies zones, they are useful tools for paleoecological reconstructions.

Online since December 25, 2013


Letter 7 [2013]: Dissocladella hauteriviana MASSE in MASSE et al., 1999 (non MASSE, 1976), another lower Urgonian Dasycladalean alga revisited, by Bruno GRANIER.-
Format [HTML] or [PDF 1,990 KB]
Reference: [CG2013_L07]
DOI: 10.4267/2042/53035
Lang.: 

CG2013_L07_thumb Abstract:   First ascribed to the Triploporellacean genus Dissocladella (Pia in Rao & Pia, 1936), the species D. hauteriviana Masse in Masse et al., 1999, was supposedly characterized by a thallus bearing whorls of laterals each consisting of a stumpy primary with a tuft of four slim secondaries at its top. A restudy of the laterals proves that they split, not only once, but several times, and stepwisely decrease in diameter. The species is re-ascribed to the Family Thyrsoporellaceae in a new combination to the genus Deloffrella Granier & Michaud, 1987. Its known stratigraphic range is rather short (Late Valanginian-earliest Barremian). In addition, it disappears earlier than its companion Polyphysacean alga, i.e., Clypeina paucicalcarea (Conrad, 1970), and its geographical distribution is broader, which makes it a good index fossil for lower Urgonian carbonate platform series.

Online since December 25, 2013


Obituary notice: Jean-Paul COLIN.-
Format [HTML] or [PDF 245 KB]
Reference: [Jean-Paul_Colin]
DOI: 10.4267/2042/51849
Lang.: 

Jean-Paul_ColinJean-Paul COLIN (1948 - 2013) passed away at the end of this summer and his departure is a cruel loss for our community, not only as a scientist of international repute, but also as an outstanding organizer and, for a number of us, as a good friend.
Following his PhD degree in micropaleontology from the University of Paris VI in 1973, he spent his entire career in the exploration branch of the oil industry, first with EXXON in Houston and Bègles from 1974 to 1989, and then with ESSO REP in Bègles from 1989 to 2000. (...)
Jean-Paul COLIN was a great field and laboratory naturalist and as a scientific partner was always open to often lively discussion. His enthusiasm for the ostracods was huge and it was a pleasure to discuss with him. (...)
Being a very friendly person, he helped ostracodologists worldwide who went to him with questions, particularly the young.
Besides these activities, Jean-Paul COLIN was member of the editorial board of several international journals. (...) He was Associate Editor of Carnets de Géologie [Notebooks on Geology].

Online since November 22, 2013

 Addendum:  In order to be complete the bibliographic list of Jean-Paul Colin should also have included the following missing reference (Fida Medina, personal communication): Medina F., Vachard D., Colin J.-P., Ouarhache D. & Ahmamou M'F. (2001).- Charophytes et ostracodes du niveau carbonate de Taourirt Imzilen (Membre d'Aglegal, Trias d'Argana) : implications stratigraphiques.- Bulletin de l'Institut scientifique, Rabat, (section Sciences de la Terre), n° 23, p. 21-26.

Format [HTML] or [PDF 17 KB]

Online since February 28, 2014


Letter 6 [2013]: About the generic attribution of Megatyloceras casei HUMPHREY, 1949 (Ammonoidea, Ancyloceratina), from the Aptian of Mexico, by Josep A. MORENO-BEDMAR & Gérard DELANOY.-
Format [HTML] or [PDF 2,824 KB]
Reference: [CG2013_L06]
DOI: 10.4267/2042/51826
Lang.: 

CG2013_L06_thumb Abstract:   In the present work we review the generic attribution of the Mexican ammonoid species Megatyloceras casei Humphrey, 1949, through a careful examination of the holotype housed in the University of Michigan and with reference to new biostratigraphic data from the type locality. We assign here this species to the subfamily Cheloniceratinae and to the genus Epicheloniceras Casey, 1954.

Online since November 11, 2013


Article 8 [2013]: Daniel ŒHLERT (1849-1920): scientific biography and bibliography, by Christian C. EMIG.-
Format [HTML] or [PDF 455 KB]
Reference: [CG2013_A08]
DOI: 10.4267/2042/51825
Lang.: 

CG2013_A08_thumb Abstract:  Daniel Œhlert (1849-1920): scientific biography and bibliography.- Daniel Œhlert (1849-1920) spent his entire career in Laval (Mayenne, France). His duties as a librarian of the city of Laval, then as curator of the museums of archaeology and natural history of Laval, allowed him freedom to focus on palaeontology and geology. He worked with his wife Pauline both in the field in the departments of Mayenne and Sarthe. In between field trips in the Mayenne and Sarthe, they shared the research during their long stays in Paris, working at the Sorbonne. Œhlert's studies focused mainly on faunas of the Palaeozoic seas of Maine, Anjou and Cotentin. Œhlert devoted himself primarily on describing crinoids, trilobites and brachiopods. In his collection, located in the "Musée des Sciences" (Laval, Mayenne, France), more than 20 new genera with more than 150 new invertebrate species have been described. His geological and stratigraphical work is largely original, involving almost exclusively Palaeozoic areas in the departments of Mayenne and Sarthe, and secondarily in the departments of Orne and Ille-et-Vilaine. In 1884, he took a position at the "Service de la Carte géologique de France". More than a hundred publications spread out from 1877 ended abruptly in 1911 with the death of his wife Pauline. A list of all his works is provided.

Online since November 11, 2013


Article 7 [2013]: Revision of the Jesse Harlan JOHNSON Collection. Part 1. Some fossil Dasycladales from Guatemala, by Bruno GRANIER, Rajka RADOIČIĆ & Katica DROBNE.-
Format [HTML] or [PDF 7,459 KB]
Reference: [CG2013_A07]
DOI: 10.4267/2042/51824
Lang.: 

CG2013_A07_thumb Abstract:  This first report is a revision of fossil calcareous green algae (Dasycladales) described from the Upper Cretaceous and Paleocene series of Guatemala. Among other things in their 1965 paper J.H. Johnson and H.V. Kaska introduced three new species originally referred to the genera Acroporella, Cylindroporella, and Cymopolia. One species, which has previously been referred to the genus Cylindroporella, is a foraminifer.

 Supplementary material:  Color plates [PDF 1,368 KB]

Online since November 11, 2013


Letter 5 [2013]: Paleotropical pollen grains from the Neuquén Group, Patagonia, Argentina, by Patricia VALLATI.-
Format [HTML] or [PDF 297 KB]
Reference: [CG2013_L05]
DOI: 10.4267/2042/51218
Lang.: 

CG2013_L05_thumb Abstract:  This paper discusses the presence of elater-bearing pollen grains and other characteristic paleotropical palynomorphs in the mid to Late Cretaceous Neuquén Group at the El Zampal locality, south of Mendoza Province, Argentina.
The elaterates characterize the equatorial paleofloristic province in the Albian-Cenomanian. The species Elateroplicites africaensis is present in the pollen assemblage recovered from the lower section of the Huincul Formation, a basal  unit of the studied Neuquén Group. It represents the first record of elater-bearing pollen grains in Argentina and marks their southernmost extension. Other conspicuous paleotropical elements recorded in different lithostratigraphic units of the Neuquén Group include gymnospermous polyplicate pollen grains and angiosperm pollen, including two species of the periporate pollen genus Cretacaeiporites and the triporate pollen species Confossia vulgaris. The paleobiogeographic and biostratigraphic significance of the paleotropical sporomorph record in the Cretaceous palynofloras of the Neuquén Group at El Zampal is herein discussed.

Online since August 2, 2013


Letter 4 [2013]: Praeorbitolina claveli n.sp. (benthic Foraminifera) from the Lower Aptian sensu lato (Bedoulian) of Central Iran, by Felix SCHLAGINTWEIT, Ioan I. BUCUR, Koorosh RASHIDI & Behnam SABERZADEH.-
Format [HTML] or [PDF 1,755 KB]
Reference: [CG2013_L04]
DOI: 10.4267/2042/51217
Lang.: 

CG2013_L04_thumb Abstract:  The new orbitolinid foraminifer, Praeorbitolina claveli n.sp., is described from the Lower Aptian (Bedoulian) of Central Iran. It is characterized by an eccentric embryonic apparatus displaying both a subdivided subembryonic zone and a deuteroconch. The Barremian-Aptian orbitolinid association of this area has a typical northern Tethyan character (e.g., "association à Valserina" of Cherchi and Schroeder, 1973).

Online since August 2, 2013


Article 6 [2013]: New data on the Valanginian - Hauterivian Ammonites from the stratotypical area of Neuchâtel (Swiss Jura Mountains) : biostratigraphic implications, by Pierre-Olivier MOJON, Antonio MUSOLINO, Stefan BUCHER & Bernard CLAUDE.-
Format [HTML] or [PDF 1,254 KB]
Reference: [CG2013_A06]
DOI: 10.4267/2042/51216
Lang.: 

CG2013_A06_thumb Abstract:  New collections of Upper Valanginian - Lower Hauterivian ammonites yield precisions about the biostratigraphical scheme of the Lower Cretaceous in the stratotypical area of Neuchâtel (Swiss Jura Mountains). Thus, Stoicoceras pitrei (Busnardo, 1966) from the "Calcaire roux limoniteux" is reported in the upper Saynoceras verrucosum Biozone (Karakaschiceras pronecostatum Subzone) of the Upper Valanginian. In the Lower Hauterivian, Olcostephanus (O.) variegatus Paquier, 1900, from the upper part of the "Marnes bleues d'Hauterive" and Saynella cf. clypeiformis (d'Orbigny, 1841) from the "Marnes d'Uttins" (top of the lower part of the "Pierre jaune de Neuchâtel") extend greatly the range of the Lyticoceras nodosoplicatum Biozone compared to a more reduced Crioceratites loryi Biozone indicated by Saynella neocomiensis (Baumberger, 1905) and a unique specimen of Crioceratites cf. gr. loryi (Sarkar, 1955) found in 1907.

Online since August 2, 2013


Article 5 [2013]: Study of the species Ochetoceras (Ochetoceras) canaliculatum (de Buch, 1831) (Middle Oxfordian, Transversarium Zone), by Philippe QUEREILHAC.-
Format [HTML] or [PDF 4,465 KB]
Reference: [CG2013_A05]
DOI: 10.4267/2042/51215
Lang.: 

CG2013_A05_thumb Abstract:   The species Ochetoceras (Ochetoceras) canaliculatum (de Buch, 1830 [1831]), discussed here, is certainly the most representative of the Transversarium Zone (Middle Oxfordian) in the Tethyian domain (Mediterranean Province). It appears in the Parandieri Subzone and seems to go extinct in the Stenocycloides Subzone (Late Oxfordian, base of the Bifurcatus Zone). It is abundantly represented in the ammonite populations and has a wide geographical range and has a wide geographical spread. Analysis shows that it is always associated with species referred to Ochetoceras (Ochetoceras) hispidum [M] (Oppel, 1863) and Glochiceras (Glochiceras) subclausum [m] (Oppel, 1863) ; many authors have long thought that it was a single species. These three "species" are thus here united under the name Ochetoceras (Ochetoceras) canaliculatum (de Buch, 1831): macroconchs corresponding to the "morphs" canaliculatum and hispidum are polymorphic evolving from a narrow to a wide whorl cross section whereas the "morph" subclausum is a sexual dimorphic microconch.

Online since August 2, 2013

 Erratum:  On page 219, one should read:
"À la lecture d'anciennes publications, il est apparu que le nom d'auteur (de Buch) avait été mal transcrit. L'Ammonites canaliculatus Graf von Münster, de Buch, 1831, l'Ammonites hispidus Oppel, 1863, et l'Ammonites subclausus Oppel, 1863, sont maintenant réunies sous l'appellation Ochetoceras (Ochetoceras) canaliculatum (de Buch, 1831)",
instead of:
"À la lecture d'anciennes publications, il est apparu que le nom d'auteur (de Buch) avait été mal transcrit et que la date de création de l'espèce (1831) était erronée : ces faits ont été mis en évidence à l'aide de l'I.C.Z.N. (4ème édition, 1999), inconnu à l'époque. L'application des articles de ce dernier a permis de corriger ces erreurs. L'Ammonites canaliculatus Graf von Münster -- figurée dans la publication de von Zieten datée de 1832 --, l'Ammonites hispidus Oppel, 1863 et l'Ammonites subclausus Oppel, 1863 -- toutes deux figurées et décrites par cet auteur --, sont maintenant réunies sous l'appellation Ochetoceras (Ochetoceras) canaliculatum (de Buch, 1831)".

Format [HTML] or [PDF 30 KB]

Online since August 4, 2013


Article 4 [2013]: L'Estellon (Baronnies, France), a "Rosetta Stone" for the Urgonian biostratigraphy, by Bruno GRANIER, Bernard CLAVEL, Michel MOULLADE, Robert BUSNARDO, Jean CHAROLLAIS, Guy TRONCHETTI & Pierre DESJACQUES.-
Format [HTML] or [PDF 8,169 KB]
Reference: [CG2013_A04]
DOI: 10.4267/2042/51213
Lang.: 

CG2013_A04_thumb Abstract:  Shallow-water assemblages of transported (freshly reworked) bioclasts (mainly orbitolinids and dasycladales) are observed in the deeper facies of the "Vocontian Trough" (SE France). There these benthic assemblages can be directly correlated with ammonite zones. These new finds give an Early Barremian age to the earliest record of Palorbitolina lenticularis as well as those of four so-called typical Early Aptian representatives of the genus Orbitolinopsis. Actually most orbitolinid species recorded from the Late Barremian interval are now found present in Lower Barremian strata at L'Estellon. Some currently used correlation schemes for the Urgonian platforms, that are based on partial stratigraphic distribution ranges for the orbitolinids, --and consequently derived conclusions and hypotheses-- require at least in-depth revisions when they are not definitively refuted.

Online since July 22, 2013

 Erratum:   On page 175, first column (bottom), one should read: "2) Genus Dictyoconus Blanckenhorn, 1900", instead of: "2) Genus Dictyorbitolina Blanckenhorn, 1900".

On page 175, second column (top), one should read: "Provisionally attributed to the genus Dictyoconus", instead of: " Provisionally attributed to the genus Dictyorbitolina".

On page 179, second column, one should read: "nor between Dictyoconus ? vercorii and Dictyoconus aff. vercorii", instead of: "nor between Dictyorbitolina ? vercorii and Dictyorbitolina aff. Vercorii".

Similarly, on Plate 8, figs. 10-12, Plate 9, fig. 7, and Plate 10, fig. 4, one should read "Dictyoconus ? vercorii" instead of "Dictyorbitolina ? vercorii".

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Online since December 25, 2013


Article 3 [2013]: Barremian ammonite fauna from L'Estellon section (Baronnies, SE France): preliminary biostratigraphic results, by Robert BUSNARDO, Bruno GRANIER, Bernard CLAVEL & Jean CHAROLLAIS.-
Format [HTML] or [PDF 4,565 KB]
Reference: [CG2013_A03]
DOI: 10.4267/2042/51212
Lang.: 

CG2013_A03_thumb Abstract:   The study of the ammonite fauna in the L'Estellon section (Drôme department, SE France) allows us to date episodes with gravitational deposition in this area of the "Vocontian Trough". They span most of the Barremian Stage, from the Nicklesi Zone up to the Giraudi Zone. We did not identify any Bedoulian redeposits, the "Bedoulian ridge" auct. being latest Barremian in age.

Online since July 22, 2013


Letter 3 [2013]: Cornulitid tubeworms from the Ordovician of eastern Baltic, by Olev VINN.-
Format [HTML] or [PDF 635 KB]
Reference: [CG2013_L03]
DOI: 10.4267/2042/51214
Lang.: 

CG2013_L03_thumb Abstract:  Nine species of cornulitids are systematically described here from the Ordovician of Estonia. The earliest species, Cornulites semiapertus, appears in the late Darriwilian (Middle Ordovician), the next two species appear in the Sandbian and there are a further six new species in the Katian, which indicates a rapid diversification of cornulitids in the Late Ordovician of Baltica. All the studied cornulitids from the Ordovician of Estonia occur in relatively shallow-water normal-marine sediments of a carbonate platform. The cornulitids are found encrusting mostly brachiopod shells (both syn vivo and post mortem).

Online since July 22, 2013


Memoir 2 [2013]: Priabonian mammals and reptiles from the Platé Massif (Savoy, France), by Michel DELAMETTE & Jean A. REMY.-
Format [HTML] or [PDF 5,875 KB]
Reference: [CG2013_M02]
DOI: 10.4267/2042/50056
Lang.: 

CG2013_M02_thumb Abstract:  A lens of marly limestone at the bottom of the Tertiary series of the Grandes Platières (Platé Massif, Savoy) has yielded the most important collection of fossil vertebrates so far known from the Paleogene of Western Alps. Ungulate mammals are represented by 35 teeth to be referred to 9 taxa (4 perissodactyls and 5 artiodactyls). This new fauna appears contemporaneous with that of La Débruge (MP 18 level), dated at about 35.5 My old. The new locality, called "gisement des Perdrix", is stratigraphically located 20-35 m underneath the other one in which Weidmann et al. (1991) had found mammals to be attributed to the MP 20 level. So the new fauna is about 1.5 My older than this latter. Its faunal composition and the swampy nature of the deposit suggest that the occurring mammals were living in variegated surroundings, with woody areas close to wet marshy ones.

Online since May 17, 2013


Article 2 [2013]: Xerticeras gen. nov., a new genus of micromorphic heteromorph ammonite (Ancyloceratina, Ancyloceratidae) from the lower Aptian of Spain, by Gérard DELANOY, Josep A. MORENO-BEDMAR, José J. RUIZ & Domingo TOLÓS LLÁDSER.-
Format [HTML] or [PDF 4,285 KB]
Reference: [CG2013_A02]
DOI: 10.4267/2042/49315
Lang.: 

CG2013_A02_thumb Abstract:  Biostratigraphical and paleontological studies of lower Aptian material from the Eastern Iberian Chain (Spain) have revealed the presence of a new genus of micromorphic heteromorph ammonite: Xerticeras gen. nov. (type species: Xerticeras salasi sp. nov.). This new taxon comes from the Deshayesites deshayesi and Dufrenoya furcata ammonite zones. The size difference observed in the population is considered due to sexual dimorphism.

Online since April 24, 2013


Letter 2 [2013]: An event bed with abundant Skolithos burrows from the late Pridoli (Silurian) of Saaremaa (Estonia), by Olev VINN & Mark A. WILSON.-
Format [HTML] or [PDF 1,833 KB]
Reference: [CG2013_L02]
DOI: 10.4267/2042/49316
Lang.: 

CG2013_L02_thumb Abstract:  Abundant Skolithos burrows are here described from a possible regressive event bed at Ohesaare cliff (Pridoli), Saaremaa, Estonia. The vertical, cylindrical burrows are identified as Skolithos rather than Trypanites because they intercept and bypass rather than cut bioclasts in the limestone matrix. The absence of encrustation on the upper bedding surface also is evidence that these traces are soft-sediment burrows rather than hardground borings. We interpret this intensive bioturbation by Skolithos-producing organisms as an indicator of a shallow water paleoenvironment with high hydrodynamic energy.

Online since April 24, 2013


Article 1 [2013]: New paleontological and stratigraphical data at the Aptian - Albian transition in the Ariege Pyrenees (France), by Jacques REY, Josep Anton MORENO-BEDMAR, Michel BILOTTE & Ricardo MARTÍNEZ.-
Format [HTML] or [PDF 1,089 KB]
Reference: [CG2013_A01]
DOI: 10.4267/2042/48733
Lang.:  

CG2013_A01_thumb Abstract:  The discovery of ammonites of the Aptian - Albian transition (Hypacanthoplites jacobi and Leymeriella tardefurcata biozones) in the Urgonian series from the sedimentary section exposed in the Arize massif invalidates their former attribution to the lower Clansayesian which was proposed on the basis of unconstrained paleontological arguments.

Online since February 28, 2013


Letter 1 [2013]: Heteroporella ? paucicalcarea (Conrad, 1970), an Urgonian Dasycladalean alga revisited, by Bruno GRANIER.-
Format [HTML] or [PDF 1,412 KB]
Reference: [CG2013_L01]
DOI: 10.4267/2042/48737
Lang.: 

CG2013_L01_thumb Abstract:  When the species Heteroporella ? paucicalcarea (Conrad, 1970) was erected it was left in open nomenclature. Later on new combinations were introduced but did not meet a general agreement among paleophycologists. Considering the current acception of the Dasycladalean families, we ascribe it to the Family Polyphysaceae and subsequently to the genus Clypeina (Michelin, 1845). Its known stratigraphic range is rather brief (Late Hauterivian-Early Barremian), which makes it a good index fossil in Urgonian carbonate platform series. Its geographical distribution is apparently restricted to Western Europe (France, Spain and Switzerland).

Online since February 28, 2013


Memoir 1 [2013]: Revision of the species Hemidiadema rugosum Agassiz, 1846, and H. neocomiense (Cotteau, 1869) (Euechinoidea, Camarodonta, Glyphocyphidae) from the Lower Cretaceous of the Basin of Paris (France), by Arnaud CLÉMENT.-
Format [HTML] or [PDF 2,725 KB]
Reference: [CG2013_M01]
DOI: 10.4267/2042/48481
Lang.: 

CG2013_M01_thumb Abstract:  Hemidiadema rugosum Agassiz, 1846, and H. neocomiense (Cotteau, 1869) are small and poorly known "regular" echinoid species. They were the source of much confusion due to their rarity and the inadequacy of their original descriptions. Both species are revised here to clarify their differences and taxonomic status. This revision is based on six specimens of H. rugosum (including the holotype, not shown by its original author), all from the locus typicus and stratum typicum (Clansayesian [Upper Aptian sensu gallico] "Grès ferrugineux" from Grandpré, Ardennes) and on a single specimen of H. neocomiense from the stratum typicum (Lower Hauterivian (? Lyticoceras nodosoplicatum Zone) "Calcaire à Spatangues" from Ville-sur-Saulx (Meuse), a locality near to the locus typicus (Auxerre, Yonne)). For this latter species, a neotype is designated to replace the holotype that is lost. Remarks on the paleoecology and stratigraphic and geographic distributions of these two species are given. The revision of these two species provides an opportunity to propose an emended diagnosis of the genus Hemidiadema Agassiz, 1846, a poorly known member of the Glyphocyphidae.

Online since January 21, 2013


up2  

2012 (vol. 12) 

Letter 4 [2012]: Inflation in the number of monospecific genera in brachiopod: progress or regression? A trivial approach to a real problem, by Rémy GOURVENNEC.-
Format [HTML] or [PDF 302 KB]
Reference: [CG2012_L04]
DOI: 10.4267/2042/48396
Lang.: 

CG2012_L04_thumb Abstract:  Since the 19th century, about 1800 brachiopod genera or subgenera have been erected for the period covering the Silurian to the Devonian. In recent years, there has been a pronounced increase in the number of genera containing a single species. Without questioning the technological advances, one can, however, question the value and usefulness of monospecific genera both for systematics and palaeogeographical studies. Some editorial policy regarding erection of new monospecific genera and/or the evaluation of calls for projects are now needed.

Online since December 25, 2012


Article 8 [2012]: On the origin of the genus name Thecidea, a review, by Christian C. EMIG.-
Format [HTML] or [PDF 812 KB]
Reference: [CG2012_A08]
DOI: 10.4267/2042/48306
Lang.: 

CG2012_A08_thumb Abstract:  The genus Thecidea has been figured before it was described that gave rise to various and erroneous interpretations, in particular by English-writing authors. It must be undoubtedly attributed to Defrance in Cuvier & Brongniart (1822). Four other descriptions derived from the original name Thecidea are nomen nullum, and are partially responsible for confusion before Thecidea was split in several new genera. Finally, only fossil species belong today to Thecidea. The history of the attribution of the author's name to Thecidea is described in detail. The type species and its synonyms, as well as the classification of the Thecidea are given.

Online since December 10, 2012


Memoir 2 [2012]: Mediterranean Neocomian belemnites, part 4: belemnites of the Barremian stratotype section, by Nico M.M. JANSSEN, Arnaud CLÉMENT & Willem BONT.-
Format [HTML] or [PDF 10,329 KB]
Reference: [CG2012_M02]
DOI: 10.4267/2042/48307
Lang.: 

CG2012_M02_thumb Abstract:  This paper deals with the distribution of belemnites in the latest Hauterivian to early Bedoulian of the Angles Barremian Stratotype Section (ABSS). The distribution of the belemnites in the ABSS is not uniform, mainly due to the inaccessibility of certain beds. To cover this, and to compare the distribution with more proximal settings, we investigated a section to the north of Le Bourguet. The latest Hauterivian sediments mainly yield Hibolithes ex gr. subfusiformis besides some Duvalia ex gr. dilatata. The earliest Barremian sediments deliver a richer association that yields the last Hibolithes spp. The first typical Barremian belemnites occur just one bed above the Hauterivian-Barremian boundary based on ammonites. This belemnite association (BaBA1) consists of Duvalia ex gr. silesiaca-gagrica, Duvalia pontica and several species of Hibolithes. At the boundary between the Nicklesia pulchella and the Kotetishvilia compressissima zones the diversity increases and the first classical Barremian belemnites occur. These were formerly attributed to Mesohibolites (BaBA2). These species are herein attributed to a new genus Shvetsovia. Together with the duvaliids from BaBA1 they were first described from Abkhasia by Shvetsov (1913). The latest Early Barremian (BaBA3) and the earliest Late Barremian (BaBA4) show well diversified belemnite associations, with many classical species, dominated by few genera closely resembling the true Mesohibolites. Eventually, these belemnite associations are compared to more proximal sections within the Vocontian Basin, and areas outside the Vocontian Basin (chiefly Hungary and Georgia). Some differences in the frequency and abundance of several species in these different palaeogeographical settings are believed to indicate differences in natural habitat. Duvalia ex gr. grasiana appears to be more abundant in more distal sections, while juvenile Mesohibolitidae, Conohibolites and Curtohibolites appear to be more abundant in the more proximal environments. Finally, a biozonation is presented and defined based on the distribution of the belemnites in the ABSS. This biozonation appears applicable in the more proximal sections, although some biozones are diachronous. The first Mesohibolites occur in the Upper Barremian Imerites giraudi Zone. In the Barremian-Bedoulian boundary sediments, as defined in the ABSS, Neohibolites first occurs, but the latter is only dominant in the marly sediments above the "calcareous Bedoulian". In the Late Barremian-early Bedoulian seven main belemnite associations can be distinguished, viz. BaBA5, BaBA6, BaBA7, BdBA1, BdBA2, BdBA3 and BdBA4. The following new species and genera are described: Hibolithes keleptrishvilii sp. nov. (latest Hauterivian), Duvalia vermeuleni sp. nov. (Early Barremian), Curtohibolites (?) bourguetensis sp. nov. (Early Barremian), and Shvetsovia gen. nov. (late Early-early Late Barremian). Besides, the Late Barremian yields the new species Mesohibolites anglesensis. Moreover, eleven species are described in open-nomenclature.

Online since December 10, 2012


Letter 3 [2012]: A new upper Bedoulian section in the Aptian stratotypic area: Croagnes (5 km NW of Gargas, Vaucluse, SE France), by Michel MOULLADE, Guy TRONCHETTI, Christine BALME & Pascal MAUROUX.-
Format [HTML] or [PDF 1,105 KB]
Reference: [CG2012_L03]
DOI: 10.4267/2042/47550
Lang.: 

CG2012_L03_thumb Abstract:  The discovery and exploitation of a new outcrop of the "A1 Unit of yellow marls and marly limestones" of Leenhardt (1883), comprised between the Urgonian limestones and the "Aptian marls" of the authors, leads to question the generalized attribution of this formation to the Deshayesites grandis ammonite Subzone. Data from this section at Croagnes rather lead to place A1, at least locally in the stratotypic area of the surroundings of Apt, at the level of the onset of the anoxic event OAE1a, just below the Roloboceras hambrovi Subzone. The assumed isochroneity of this Unit is also questioned.

Online since October 2, 2012


Article 7 [2012]: Encrustation and bioerosion on late Sheinwoodian (Wenlock, Silurian) stromatoporoids from Saaremaa, Estonia, by Olev VINN & Mark A. WILSON.-
Format [HTML] or [PDF 2,048 KB]
Reference: [CG2012_A07]
DOI: 10.4267/2042/47551
Lang.: 

CG2012_A07_thumb Abstract:  A shallow shelf carbonate platform (pelletal limestone facies) stromatoporoid association from the late Sheinwoodian of Saaremaa (Baltica) contains a diverse assemblage of sclerobionts (both epi- and endobionts). The studied stromatoporoids vary from low domical to extended domical shapes. Cornulites sp. aff. C. stromatoporoides, Conchicolites sp., Anticalyptraea calyptrata, microconchids, tabulate (Aulopora sp., Catenipora sp. and favositids) and rugose corals, sheet-like trepostome bryozoans, and discoidal crinoid holdfasts encrust the stromatoporoids. The dominant sclerozoans were tabulate and rugose corals, which is significantly different from several analogous Silurian sclerobiont communities. There may have been taxonomic polarity between an upper surface and a cryptic sclerozoan community. Bioerosion occurs as macroborings in 45.5 % of studied (N=22) stromatoporoids. Endobionts were represented by Trypanites and Palaeosabella borings, as well as embedded symbiotic rugose corals and Cornulites stromatoporoides.

Online since October 2, 2012


Letter 2 [2012]: Presence of Frambocythere COLIN, 1980, (limnic ostracode) in the Maastrichtian of the Zagros Mountains, Iran: a newly recognized link between southern Europe and the Far East, by Jean-Paul COLIN, Hossein VAZIRI-MOGHADDAM, Amrollah SAFARI & Samira SHARIARI GRAI.-
Format [HTML] or [PDF 1,185 KB]
Reference: [CG2012_L02]
DOI: 10.4267/2042/47503
Lang.: 

CG2012_L02_thumb Abstract:  The limnic ostracode Frambocythere tumiensis zagrosensis subsp. nov. (Limnocytheridae, Timiriaseviinae), has been found for the first time in Iran. The strata containing this species are in the lower part of the Tarbur Formation in the interior Fars of the Zagros Mountains. The Late Maastrichtian age is indicated by rudists, larger foraminifers (Omphalocyclus macroporus, Loftusia spp.) and planktonic foraminifers (Contusotruncana contusa-Racemiguembelina fructicosa Zone) present in the upper part of the Tarbur Formation. The Maastrichtian age is confirmed by the occurrence in the same strata of the charophytes Platychara shanii, Peckichara cristellata and Stephanochara cf. producta. The genus Frambocythere Colin, 1980, was until now known mostly from the Upper Maastrichtian to Middle Eocene of southern Europe, India and China, as well as the Albian of the Democratic Republic of Congo. The presence of Frambocythere gr. tumiensis in Iran is therefore a newly recognized link between southern Europe and the Far East (China).

Online since September 17, 2012


Memoir 1 [2012]: Study of the Phylloceratoidea fauna of the Valanginian marls of Senez-Lioux (Alpes-de-Haute-Provence, France). Comparison with some Drôme and Ardèche Valanginian localities, by Bernard JOLY & Philippe MERCIER.-
Format [HTML] or [PDF 7,154 KB]
Reference: [CG2012_M01]
DOI: 10.4267/2042/47505
Lang.: 

CG2012_M01_thumb Abstract:  The recent "Révision de la Paléontologie française de d'Orbigny (1840-42, tome premier, Terrains crétacés)" has allowed a better understanding of Ammonites calypso (d'Orbigny, 1841), so that a more accurate age of the species is known at its type-locality. At first the authors of this memoir had searched for other specimens in the Valanginian marls of Senez-Lioux in order to give it the most correct age.
The Phylloceratoidea do not give a precise age of the strata from which the specimens were collected so the authors have determined the ammonites from five successive horizons. This work has shown the Lower Valanginian and two zones of Upper Valanginian (the zone with Verrucosum and the zone with Peregrinus ?, the presence of this last zone is less certain). The zone with Furcillata of Upper Valanginian has not been proved.
The Phylloceratoidea are abundant in Senez-Lioux. Six species have been identified: Phylloceras (Hypophylloceras) serum (Oppel, 1865), Phylloceras (Hypophylloceras) tethys (d'Orbigny, 1841), Sowerbyceras calypso (d'Orbigny, 1841), Ptychophylloceras (Semisulcatoceras) semisulcatum semisulcatum (d'Orbigny, 1841), Ptychophylloceras (Semisulcatoceras) semisulcatum (d'Orbigny, 1841) diphyllum (d'Orbigny, 1841), Phyllopachyceras rogersi (Kitchin, 1908) and a new species: Phylloceras (Goretophylloceras) liouxense n. sp. This new species was found in the Alpes-de-Haute-Provence (material collected by Philippe Mercier and Bernard Joly) and in the Drôme area (material collected by Laurent Vareilles and Philippe Mercier).
These ammonites are small (diameter 5-28 mm) and seem to belong to the juvenile stage. For a long time the Vocontian basin seems to have been the egg-laying area of these Cephalopods. In the Valanginian marls there are specimens whose diameter is less than 5 mm. They have not been determined in this study. However their presence is significant. The pyritic specimens and the iron oxide specimens (for example the limonitic specimens) are not necessarily small in size. In the marly facies there are very large pyritic specimens, which are among the largest known (Joly, 2000, p. 173). In Senez-Lioux the smallest specimens are not the nuclei of the largest ones. They are not small adults because we are unable to see the contraction of the last septa showing the slowing down of their growth. The beginning of the body chamber, which is present in many of the specimens, proves that these specimens were merely not nuclei and definitely they have not attained sexual maturity.
The many specimens gathered permitted a statistical study of the populations especially of the species Phylloceras (Hypophylloceras) serum (Oppel, 1865), Phylloceras (Hypophylloceras) tethys (d'Orbigny, 1841), Phylloceras (Goretophylloceras) liouxense n. sp., Ptychophylloceras (Semisulcatoceras) semisulcatum semisulcatum (d'Orbigny, 1841), and Ptychophylloceras (Semisulcatoceras) semisulcatum (d'Orbigny, 1841) diphyllum (d'Orbigny, 1841). The species Sowerbyceras calypso (d'Orbigny, 1841) and Phyllopachyceras rogersi (Kitchin, 1908) are represented by very few specimens.
The fossils gathered in some deposits from the Drôme and Ardèche area have allowed us to further our knowledge about the Valanginian faunas of the Vocontian Basin. In particular they have permitted the statistical study of a population of the very rare species Ptychophylloceras (Semisulcatoceras) semisulcatum semisulcatum (d'Orbigny, 1841) as only one specimen was identified among the fossils gathered in the deposits of Senez-Lioux but is more abundant in the Valanginian from the Drôme.

Online since September 17, 2012


Article 6 [2012]: Proposal for the Thuoux section as a candidate for the GSSP of the base of the Oxfordian stage, by Dominique FORTWENGLER, Didier MARCHAND, Alain BONNOT, Rémi JARDAT & Daniel RAYNAUD.-
Format [HTML] or [PDF 1,097 KB]
Reference: [CG2012_A06]
DOI: 10.4267/2042/47431
Lang.: 

CG2012_A06_thumb Abstract:  The Thuoux section, located in South-Eastern Basin of France (coordinates: 44°30'55"E; 5°42'25"N), is a section that satisfies numerous demanding criteria as reference section (GSSP) for the base of the Oxfordian stage. Sedimentation was continuous in that the abundant ammonitic fauna yields no detectable hiatuses. The stratigraphic boundary is located between the Lamberti Zone and the Mariae Zone or more precisely between the Paucicostatum horizon (Marchand, 1979) and the Thuouxensis horizon (Fortwengler & Marchand, 1994a). In this section, there is a perfect mixing between Boreal ammonites (Cardioceratinae) whose species are used as stratigraphic markers and Submediterranean/Subboreal ammonites (Hecticoceratinae, Peltoceratinae and Perisphinctinae) that provide further possibilities for wide correlation of this boundary. Finally, parallel ammonite zonations have been established with great  precision (biohorizons and sometimes "sub-biohorizons") in various areas of France, with different palaeoenvironments. The Thuoux section permits correlations with central and eastern Europe as well as North America, based on Cardioceratinae successions, and with South America, using Peltoceratinae. Thickness of the Callovian-Oxfordian transitional beds in the Thuoux section has allowed detailed sedimentological studies and astronomical calibration of the Lower Oxfordian (Boulila, 2008; Boulila et al., 2008). The Thuoux section is located at the centre of a set of more than thirty sections where the base of the Oxfordian stage is visible (Fortwengler, 1989; Fortwengler & Marchand, 1994a, b, c, d).

Online since July 14, 2012


Article 5 [2012]: Hunting for the 405-kyr eccentricity cycle phase at the Cretaceous-Paleogene boundary in the Aïn Settara section (Kalaat Senan, central Tunisia), by Michel HENNEBERT.-
Format [HTML] or [PDF 2,077 KB]
Reference: [CG2012_A05]
DOI: 10.4267/2042/47314
Lang.: 

CG2012_A05_thumb Abstract:  The Aïn Settara section (Kalaat Senan, central Tunisia) shows a continuous and well exposed marl-limestone alternation, extending from the Upper Maastrichtian to the basal Danian. The section reveals the superposition of several cycles, which correspond to the combined astro-climatic effect of both eccentricity and precession. Based on the ~100-kyr eccentricity and the ~21-kyr precession cycles, a floating chronometric scale is proposed. Thanks to this scale, the sedimentary and biological events of the section are dated with respect to the Cretaceous-Paleogene (K-Pg) boundary taken as the reference. Highlighting the very stable 405-kyr eccentricity cycle allows on one side to confirm the relevance of the established time scale and on the other side to determine the phase of this important signal with respect to the K-Pg boundary event.

Online since May 21, 2012


Article 4 [2012]: Paleontologic and stratigraphic overview of the Paleogene in eastern Saudi Arabia, by Nestor J. SANDER.-
Format [HTML] or [PDF 1,387 KB]
Reference: [CG2012_A04]
DOI: 10.4267/2042/47293
Lang.: 

CG2012_A04_thumb Abstract:  The beds of early Tertiary age in eastern Saudi Arabia are in large part chemical precipitates laid down in a shallow epicontinental sea. The sequence is divided into three formations, each clearly differentiated in both lithology and fauna. From bottom to top they have been named the Umm er Radhuma, Rus and Dammam formations. Ecologic conditions remained more or less uniform for considerable lengths of time. Consequently, the fauna, made up mainly of Foraminifera, became well adapted to the environment, as demonstrated by the abundance of some species. The great number of individuals of these species have a range of variability much broader that that seen in other areas of their occurrence. The detailed study of these variations has demonstrated that species have often been defined on too small a number of individuals. The abundance of specimens has allowed evolutionary trends in species to be traced even to the extent that in the end some variants must be classed as a discrete genus.

Online since May 11, 2012


Obituary notice : Nestor J. SANDER.-
Format [HTML] or [PDF 424 KB]
Reference : [Nestor_Sander]
DOI: 10.4267/2042/48262
Lang.: 

Nestor_SanderNestor John SANDER (December 5, 1914 - February 11, 2012), "Sandy" for his friends, was a living history book, describing himself as a positivist. (...) Nestor was sent as a junior geologist for his first assignment to Saudi Arabia (...). That was before World War II started and much before the country became known as the major worldwide oil producer. (...) Nestor was one of the founders of Carnets de Géologie: many non-native English speakers will remember him as a very kind and generous person who, for instance, helped them polish their manuscripts.

Online since March 11, 2012


Article 3 [2012]: Inconsistencies in proposed annelid affinities of early biomineralized organism Cloudina (Ediacaran): structural and ontogenetic evidences, by Olev VINN & Michał ZATOŃ.-
Format [HTML] or [PDF 1,036 KB]
Reference: [CG2012_A03]
DOI: 10.4267/2042/46095
Lang.: 

CG2012_A03_thumb Abstract:  Cloudina, an important Ediacaran index fossil, is considered as one of the earliest biomineralizing organisms. Its biological affinities have not been fully resolved and phylogenetic links with both annelids and cnidarians have traditionally been suggested. Differences in tube morphology, ultrastructure and biomineralization suggest that Cloudina is not closely related to any recent skeletal annelid (e.g., serpulids, sabellids and cirratulids) and their skeletons are not homologous. The way of asexual reproduction in Cloudina resembles more that of cnidarians. The presence of a closed tube origin (base) in Cloudina is also compatible with the hypothesis of an animal of cnidarian grade.

Online since March 12, 2012


Letter 1 [2012]: Shell repair in Anticalyptraea (Tentaculita) in the late Silurian (Pridoli) of Baltica, by Olev VINN.-
Format [HTML] or [PDF 1,005 KB]
Reference: [CG2012_L01]
DOI: 10.4267/2042/46096
Lang.: 

CG2012_L01_thumb Abstract:  Shell repair is common in the late Silurian (Pridoli) encrusting tentaculitoid tubeworm Anticalyptraea calyptrata from Saaremaa, Estonia (Baltica), and is interpreted here as a result of failed predation. A. calyptrata has a shell repair frequency of 29 % (individuals with scars) with 17 specimens. There is probably an antipredatory adaptation, i.e. extremely thick vesicular walls, in the morphology of Silurian Anticalyptraea. The morphological and ecological evolution of Anticalyptraea could thus have been partially driven by predation.

Online since March 12, 2012


Article 2 [2012]: Revision of the brachiopod species described by A. RISSO, by Christian C. EMIG.-
Format [HTML] or [PDF 674 KB]
Reference: [CG2012_A02]
DOI: 10.4267/2042/45933
Lang.: 

CG2012_A02_thumb Abstract:  Although Risso's collection has not been found, the current list of twelve recent brachiopod species and thirteen fossil ones identified and described by Risso (1826) in the marine and terrestrial vicinities of Nice deserves revision by taking into account the synonyms accepted today. Adding Argyrotheca cistellula reported in 1920, the list of the extant species of brachiopods collected in the Mediterranean Sea has remained the same until 1994, date from which it increases by two species. Three of the species described by Risso as belonging to Terebratula have been attributed as new species to him: Joania cordata, Argyrotheca cuneata, Lacazella mediterranea, all three are type species of their genus. For the fossil species, only two were identified as synonyms for Terebratula terebratula. Criticized several times, sometimes too severely, for his works on the Mollusca, to which the Brachiopoda were attributed, Risso (1826) as an amateur naturalist completed a honourable work on this latter group, entirely comparable with those of the majority of its contemporaries and more recent authors on this group.

Online since February 15, 2012


Article 1 [2012]: Distribution of brachiopod assemblages in Oxfordian strata of central France, by Annick BOULLIER & Rosemarie FILIPPI.-
Format [HTML] or [PDF 2,153 KB]
Reference: [CG2012_A01]
DOI: 10.4267/2042/45932
Lang.: 

CG2012_A01_thumb Abstract:  In the Berry area, situated in the center of France, the Oxfordian deposits are represented by successions of well individualized and dated formations in which brachiopods have been studied in detail. Several assemblages of brachiopods were found that have given indications on the age of the levels. Some have been recognized within areas more or less far away allowing us to establish correlations.

Online since February 15, 2012


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2010 (vol. 11) 

Article 5 [2011]: Xenobrochus norfolkensis (Brachiopoda: Dyscoliidae), a new species from the Norfolk Ridge, New Caledonia, South-West Pacific, by Maria Aleksandra BITNER.-
Format [HTML] or [PDF 2,151 KB]
Reference: [CG2011_A05]
DOI: 10.4267/2042/45792
Lang.: 

CG2011_A05_thumb Abstract:  The genus Xenobrochus, with the type species Gryphus africanus Cooper, 1973, was erected for short-looped brachiopods of small size, rectimarginate and having a loop with anteriorly convex transverse band. A new species of Xenobrochus, X. norfolkensis sp. nov. has been identified in the material collected during the French cruises SMIB 8, NORFOLK 1 and NORFOLK 2 to the Norfolk Ridge, New Caledonia, SW Pacific. This species differs from those hitherto described in the absence of cardinal process and relatively wide outer hinge plates. The genus, represented now by nine species, has a distribution restricted to the Indian Ocean and West Pacific.

Online since December 31, 2011


Memoir 2 [2011]: The Early Aptian (Early Cretaceous) ammonites from the Aralar Mountains, Basque-Cantabrian Basin, Northern Spain, by Seyed Naser RAISOSSADAT.-
Format [HTML] or [PDF 1,498 KB]
Reference: [CG2011_M02]
DOI: 10.4267/2042/45794
Lang.: 

CG2011_M02_thumb Abstract:  The Aralar Mountains located in northern Spain exposes a 983-m-thick succession of sediments of Early Aptian age. The lithological succession evolves from lutites, marls, and calcarenites of the Errenaga Formation to rudist micritic limestones of the Sarastarri Formation, and finally marls, lutites, and sandstones of the Lareo Formation. Based on ammonite assemblage faunas, the Deshayesites oglanlensis, D. weissi, D. deshayesi, and Dufrenoyia furcata biozones have been identified. A transition between the deshayesi and furcata zones with the co-occurrence of the ammonite genera Deshayesites and Dufrenoyia is described in the Aralar succession and is currently unique. The ammonites are described here and correlations are made with other Tethyan regions.

Online since December 31, 2011


Letter 6 [2011]: The sauropod dinosaur Cetiosaurus OWEN in the Bathonian (Middle Jurassic) of the Ardennes (NE France): insular, but not dwarf, by Eric BUFFETAUT, Bernard GIBOUT, Isabelle LAUNOIS & Claude DELACROIX.-
Format [HTML] or [PDF 389 KB]
Reference: [CG2011_L06]
DOI: 10.4267/2042/43897
Lang.:  

CG2011_L06_thumb Abstract:  A chevron bone from a Lower Bathonian oolitic limestone in the Ardennes (NE France) is referred to the sauropod dinosaur Cetiosaurus Owen, previously known from the Middle Jurassic of England, on the basis of its rod-like distal end. This is the first well attested occurrence of Cetiosaurus in France. The presence of Cetiosaurus remains in the Bathonian of both Oxfordshire and the Ardennes is explainable by the fact that these regions were situated on the margin of the London-Brabant Massif land area, on which sauropod populations apparently lived. Contrary to the condition observed in other sauropods found in insular environments, there is no evidence of dwarfism in Cetiosaurus from the London-Brabant Massif, probably because this emergent area was connected to the much larger Fenno-Scandian Shield.

Online since October 10, 2011


Letter 5 [2011]: Evolution of a dense outer protective tube layer in serpulids (Polychaeta, Annelida), by Olev VINN & Elena K. KUPRIYANOVA.-
Format [HTML] or [PDF 1,145 KB]
Reference: [CG2011_L05]
DOI: 10.4267/2042/43896
Lang.: 

CG2011_L05_thumb Abstract:  Although the walls of most serpulid tubes are homogeneous, tubes of certain species may contain up to four ultrastructurally distinct layers. Some of these layers are made of densely packed large crystals and others are composed of sparsely packed fine crystals. In almost all (16 of 17) examined species having layered tubes, the dense layer is located in the outer wall part and the layer(s) composed of fine and relatively sparsely packed crystals are positioned in the inner wall part. Two species have transparent tube walls made entirely of densely packed crystals. Fossil serpulid tubes with dense outer layers (DOL) are known from the Late Cretaceous (Pentaditrupa subtorquata) and the Eocene (Pyrgopolon cf. mellevillei and Rotularia spirulaea). DOL gives a characteristic smooth shiny appearance to the tube surface and presumably evolved as an adaptation against drilling predation by gastropods and to delay shell dissolution in the waters of the deep-sea under-saturated with calcium carbonate.

Online since October 10, 2011


Letter 4 [2011]: Aptian ammonites of Abu Dhabi (United Arab Emirates), by Robert BUSNARDO & Bruno GRANIER.-
Format [HTML] or [PDF 2,150 KB]
Reference: [CG2011_L04]
DOI: 10.4267/2042/43895
Lang.:  

CG2011_L04_thumb Abstract:  The identification of some twenty ammonite fragments from oil wells drilled in offshore Abu Dhabi revealed the presence of six Aptian genera: Cheloniceras, Epicheloniceras, Gargasiceras, Colombiceras, Pseudohaploceras, and Macroscaphites. These ammonites indicate the Furcata Zone and the succeeding Martini Zone. The Gargasian age of the upper part (HST) of the Shu'aiba as well as that of the whole of the Bab are thus firmly established.

Online since October 10, 2011


Letter 3 [2011]: Source and evolution of the clinopyroxenes in the Loire and Seine basins (France) based on grain morphology and color, by Robert ÉTIENNE & Jean-Pierre LARUE.-
Format [HTML] or [PDF 439 KB]
Reference: [CG2011_L03]
DOI: 10.4267/2042/43894
Lang.: 

CG2011_L03_thumb Abstract:  Variation in the characteristics (color, morphology) of clinopyroxene grains (CPX) in alluvial deposits and other surficial formations in the Loire valley, the Gâtinais and the Beauce show that many are pristine and come directly from recent volcanic eruptions, whereas weathered grains, clearly reworked, come from erosion of Cenozoic and Pleistocene volcanic rocks of the French Massif Central. After deposition, the CPX have been increasingly altered by longer exposures. Weathering of brown CPX yields paler minerals which are greenish-brown, colourless or two-coloured. Similarly, the CPX found in the Seine basin are from recent volcanic ash or old Sologne deposits, and not from Loire alluvial deposits, so that a Pleistocene palaeo-Loire-Seine river is improbable.

Online since October 10, 2011


Letter 2 [2011]: Computer-aided identification of the Archaeocyatha genera now available online, by Adeline KERNER, Régine VIGNES LEBBE & Françoise DEBRENNE.-
Format [HTML] or [PDF 965 KB]
Reference: [CG2011_L02]
DOI: 10.4267/2042/42329
Lang.: 

CG2011_L02_thumb Abstract:  The Archaeocyatha are a key group in several of the many discrete disciplines that together make feasible a valid history of the Earth: they are the oldest of the calcified sponges, the first metazoans to build reefs (in association with calcimicrobes), are characteristic fossils used for the biozonation of the first, pre-trilobitic Cambrian stage (Tommotian)… To date, a valid key to their identification has not been available, so a tool for that purpose has been devised: it was created using the software XPER2, and is now available free, online. Published in English, the knowledge base includes the 307 valid described genera identified by 120 descriptors (85 morphological and ontogenetic, 8 stratigraphic and geographic and 27 taxonomic). A key to identification is supplemented by detailed descriptive cards with images of type specimens of each genus and details of their morphology that aid identification.

Online since July 5, 2011


Article 4 [2011]: An outcrop with non-marine ostracodes in the Early Eocene of Djebel Amour, central Saharian Atlas, Algeria: taxonomy, palaeoecology and palaeobiogeography, by Fateh MEBROUK, Jean-Paul COLIN & Fatima HENNACHE.-
Format [HTML] or [PDF 1,866 KB]
Reference: [CG2011_A04]
DOI: 10.4267/2042/42328
Lang.: 

CG2011_A04_thumb Abstract:  An outcrop with non-marine ostracods in the Early Eocene of Djebel Amour, an outcrop well dated by a rich charophyta microflora characterizing the Peckichara disermas Zone of the Early Eocene (Lower Ypresian = Ilerdian), has yielded an interesting non-marine ostracode fauna in the Djebel Amour, Western Saharian Atlas, in Algeria. This fauna is characterized by the dominance of the genus Neocyprideis with the new species Neocyprideis meguerchiensis nov. sp., and the occasional occurrence of the genera Hemicyprideis, Perissocytheridea (P. algeriensis nov. sp.) and Limnocythere. It is the second discovery of the genus Neocyprideis in the Palaeogene of the African continent, the first one being in the Early Eocene of Senegal. The Neocyprideis are represented by 75 % of smooth and normally calcified carapaces, 20 % by reticulate-noded specimens and 5 % of only reticulate forms. This polymorphism suggests a marked seasonality with fluctuating salinity. The dominance of smooth and well calcified morphs indicates an environment with an equilibrium Ca++ / Mg++, the reticulate morphs characterizing waters richer in Mg++. The presence of noded-reticulate forms suggests seasonal influxes of organo-siliceous material from the continent and a salinity which could temporarily reach values lower or equal to 5 psu.

Online since July 5, 2011


Article 3 [2011]: Ostracods distribution in the subsurface sediments of El-Guettiate Sebkha (Skhira, gulf of Gabes). Interest for Holocene palaeoenvironmental reconstruction, by Chahira ZAÎBI, Fekri KAMOUN, Pierre CARBONEL & Mabrouk MONTACER.-
Format [HTML] or [PDF 1,598 KB]
Reference: [CG2011_A03]
DOI: 10.4267/2042/42327
Lang.: 

CG2011_A03_thumb Abstract:   A quantitative and qualitative study of the ostracods from the SG1 and BSC2 cores of El-Guettiate Sebkha of Skhira (southeastern Tunisia) has allowed the identification of different associations and the reconstruction of the Holocene palaeoenvironments. Ostracods, rich in species, provide three associations: (i) a marine association containing Aurila prasina Barbieto-Gonzalez, 1971, Cushmanidea elongata (Brady, 1868), Urocythereis oblonga (Brady, 1866), U. favosa (Roemer, 1838) (coastal marine), Basselerites berchoni (Brady, 1869), Semicytherura incongruens (G.W. Müller, 1894), S. paradoxa (G.W. Müller, 1894), S. sella (Sars, 1866), S. ruggierii (Pucci, 1955), Carinocythereis carinata (Roemer, 1838) and Paracytheridea depressa (G.W. Müller, 1894) (open marine); (ii) lagoonal association, of variable salinity, comprising Xestoleberis aurantia (Baird, 1838), Leptocythere fabaeformis (G.W. Müller, 1894) and Cytherois fischeri (Sars, 1866); (iii) brackish estuarine association subject to estuarine influence as indicated by Cyprideis torosa (Jones, 1850) and Loxoconcha elliptica Brady, 1868. The ostracods from El-Guettiate Sebkha allow us to recognize discrete palaeoenvironments that can be grouped in three phases: i) the first (6595 ± 120 - 6055 ± 30 years BP) begins with an open lagoon rich in marine ostracods followed by an estuarine lagoon (towards 6595 years BP) characterized by the richness of brackish ostracods and high energy. In the last lagoonal environment (installed towards 6055 years BP), brackish species are dominant and associated with lagoonal taxa; ii) the second phase (6055 ± 30 years BP - 5150 ± 30 years BP) is an estuarine lagoon, subject to a large marine influence in which brackish marine and lagoonal species are present in the same percentages. In this environment, littoral drift currents were responsible for the genesis of sand spits, the termination of environments and the dominance of brackish-water ostracods; iii) The last phase (5150 ± 50 years BP - recent) represents a restricted lagoon (about 5150 years BP) and finally a brackish lagoon evolved towards the sebkha environment under investigation here. This phase includes an unstable period with washover deposits resulting from an extreme climatic event.

Online since July 5, 2011


Memoir 1 [2011]: The "Theoi Marls" of Pamproux (Deux-Sèvres, France), Antecedens sub-zone (Middle Oxfordian, Plicatilis Zone): faunal diversity and discovery of new ammonite species, by Philippe QUEREILHAC & Yvon GUINOT.-
Format [HTML] or [PDF 3,154 KB]
Reference: [CG2011_M01]
DOI: 10.4267/2042/42331
Lang.: 

CG2011_M01_thumb Abstract:  Two road cuts at Doux and Pamproux in the Department of Deux Sèvres (Poitoux, France) exposed the base of the middle Oxfordian (Plicatilis Zone). Only the Pamproux section (on the Pampr'oeuf factory site) was studied in detail. There, the Plicatilis Zone is represented only by the Antecedens sudzone. Collections were made in situ and from rubble consisting solely of marls from the Antecedens Sub-zone. Sediment washing resulted in the collection of a very large number of very diversified and extremely small fossils. So a great number of individuals of two new species of Taramelliceratinae were discovered, along with two new species of "Glochiceras", their adult forms very different in size, resembling nothing so much as Ochetoceras (Ochetoceras) canaliculatum (von Buch, 1831) in the morph subclausum [m] Oppel, 1863. The sub-family Taramelliceratinae dominates the ammonite fauna.

Online since July 5, 2011


Article 2 [2011]: Difficulties in dating Pleistocene marine levels using fossil mollusk shells: the Ouljian level on the High Atlas shore, Morocco, by Abdelmajid Choukri, Oum-Keltoum HaKam & Jean-Louis Reyss.-
Format [HTML] or [PDF 2,196 KB]
Reference: [CG2011_A02]
DOI: 10.4267/2042/39245
Lang.: 

CG2011_A02_thumb Abstract:  In order to comprehend the difficulty of dating marine strata using samples of mollusks shells and in an attempt to establish criteria that help in judging the validity of a 230Th /234U age determination, we present here the results of a radioactive element analysis of some 80 samples of mollusk shells. The shells were taken from fossil marine beaches between 4 and 8 meters above current sea level. When compared with the Egyptian shore of the Red Sea these levels are taken to be related to climate stage 5 dated as about 122,000 years ago. The ages obtained are often rejuvenated regardless of site, the incidence of calcite, the amount of uranium and the relationships of 234U/238U.
Unlike coral,  mineralogical criteria cannot be used to select mollusk shells unaffected by recrystallization, for present-day shells may be composed of aragonite, others are calcitic, and others contain both minerals. In any case, the rules concerning their effects of composition on radioactivity are as yet poorly understood. With these problems in mind, we made multiple analyses on several species of of mollusks, always collected from the same sites, in order to understand progressive changes in the process of age rejuvenation and to attempt eventually to determine systematic criteria providing information on the validity of the calculated age. Possible mechanisms that may influence the incorporation of uranium in rejuvenation have been conceived and are discussed.

Online since April 27, 2011


Discussion of the Article CG2010_A01 [2011]: Discussion of: Problems in the identity of "Crioceras" barremense Kilian, 1895 (Ancyloceratida, Late Barremian), and their proposed resolution, by D. BERT et alii (CG2010_A01) [Alternative title: The nomenclatural status and the acceptation of the genus Barrancyloceras VERMEULEN, 2000, and of its type species], by Jean VERMEULEN.-
Format [HTML] or [PDF 165 KB]
Reference: [CG2010_A01R]
DOI: 10.4267/2042/39244
Lang.: 

CG2010_A01R_thumb Abstract:  This work is a reply to the paper of Bert et alii (2010) who contested the validity of the genus Barrancyloceras and its type species. The answers and precisions brought up herein deal with:

  • the nomenclatural status of Barrancyloceras barremense (Kilian, 1895);
  • the nomenclatural status of the genus Barrancyloceras Vermeulen, 2000;
  • the understanding of the species Barrancyloceras barremense (Kilian, 1895);
  • the value, as a subzone index species of subzone, of Barrancyloceras barremense and B. alpinum.

Online since April 27, 2011


Letter 1 [2011]: The role of an internal organic tube lining in the biomineralization of serpulid tubes, by Olev VINN.-
Format [HTML] or [PDF 795 KB]
Reference: [CG2011_L01]
DOI: 10.4267/2042/38798
Lang.: 

CG2011_L01_thumb Abstract:  Most known serpulid tube ultrastructures in contact with an organic inner tube lining do not show the direction in which they developed. But spherulitic prismatic structures found in the innermost part of the tube wall of Recent Crucigera websteri, C. zygophora, Floriprotis sabiuraensis, and Pyrgopolon ctenactis indicate that the structure grew toward the organic inner tube lining and also toward the tube's lumen. Similar directions of growth for this structure are seen in Hydroides sp. from the Miocene of Austria. Growth towards the tube's lumen is opposite to what one would expect if the organic inner tube lining is being used as a scaffold for the biomineralization of CaCO3.

Online since March 15, 2011


Article 1 [2011]: The Dichotomus Horizon: proposal for a new biochronologic unit of the Giraudi Zone of the Upper Barremian of southeastern France, and considerations regarding the genus Imerites Rouchadzé (Ammonoidea, Gassendiceratinae), by Didier BERT, Gérard DELANOY & Stéphane BERSAC.-
Format [HTML] or [PDF 786 KB]
Reference: [CG2011_A01]
DOI: 10.4267/2042/36091
Lang.: 

CG2011_A01_thumb Abstract:  Recent revisions of the genus Imerites Rouchadzé make it possible to introduce a new biochronologic horizon to define more precisely the lower boundary of the Giraudi Zone: the Dichotomus Horizon. Using the concept of 'interval zone', this new horizon maintains the current lower boundary of the Giraudi Zone as accepted by authors, and thus contributes to the stabilization of the Barremian zonal system. This stabilization is also strengthened by abandonment of the use of "Crioceras" cristatus d'Orbigny (nomen dubium) that ought not be used as an index species in detriment of Imerites giraudi (Kilian). The classification, origin, and intraspecific variation of the genus Imerites Rouchadzé are examined.

Online since January 17, 2011


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2010 (vol. 10) 

Article 9 [2010]: Lower Devonian faunas and palynomorphs from the Dornes Syncline (Central Iberian Zone, Portugal): stratigraphical and paleogeographical implications, by Rémy GOURVENNEC, José Manuel PIÇARRA, Yves PLUSQUELLEC, Zélia PEREIRA, José Tomás OLIVEIRA & Michel ROBARDET.-
Format [HTML] or [PDF 2,012 KB]
Reference: [CG2010_A09]
DOI: 10.4267/2042/35627
Lang.: 

CG2010_A09_thumb Abstract:  In the Dornes syncline, southern Central Iberian Zone, Portugal, the uppermost levels of the Serra do Luação Formation up to now have been considered to be of Pridoli-Lochkovian? age because they lie immediately under the Dornes Formation, which is of Pragian age and is well defined stratigraphically. New paleontological elements including benthic faunas and palynomorphs allow us to confirm that the top of the Serra do Luação Formation is securely Lochkovian, for upper Lochkovian strata are present although relatively thin. The transition from the Serra do Luação to the Dornes formations and their lithostratigraphical relationship are now clear: the terrigenous succession belongs to the Serra do Luação Formation and the limestones represent the Dornes Formation. The benthic faunas clearly have North-Gondwanan affinities.

Online since December 31, 2010


Article 8 [2010]: Systematics, phylogeny and homeomorphy of the Engonoceratidae Hyatt, 1900 (Ammonoidea, Cretaceous) and revision of Engonoceras duboisi Latil, 1989, by László BUJTOR.-
Format [HTML] or [PDF 6,671 KB]
Reference: [CG2010_A08]
DOI: 10.4267/2042/35626
Lang.: 

CG2010_A08_thumb Abstract:  The Engonoceratidae may well have originated on the shallow marine carbonate platforms of the southern margin of the Mediterranean Province of the Tethyan Realm during the earliest Albian (?latest Aptian). In the entire Tethyan Realm and beyond adaptive radiation of the group was rapid and successful during the early Albian as indicated by endemic centres in the Peruvian Basin and the Western Interior Sea (USA). Later the group successfully enlarged its distribution, and invaded some provinces (Mowry Sea, Canada) of the Boreal Realm. The mode of life of engonoceratids seems to have been nektoplanktonic, epipelagic, and stenohaline, restricted to shallow water and platform or in some cases extremely shallow (littoral and lagoonal) facies which may have helped their radiation. The group is distinctive and consists of nine genera and up to a hundred species, although its origin is still obscure. Their appearance may have been triggered by the oceanic anoxic event (OAE 1b) and their rapid rise may have been helped by their shallow water mode of life and the global mid-Cretaceous warming and rise in sea level. The fall of the engonoceratids coincides with the end-Cenomanian rapid transgression, which may have changed their shallow water habitats. Today the group is considered to have been a successful colonizer, a reliable stratigraphical indicator for shallow marine environments and a pioneer taxon for recognition of transgressive phases.
Based on new material and sutural analysis, Engonoceras duboisi is revised and assigned to Parengonoceras. A set of features consisting of a simplified ceratitid suture, lanceolate and compressed oxycone shell together comprising a shallow marine ecotype is pointed out as a successful and repeated morphotype among Mesozoic Ammonoidea, for it was repeated three times during ammonoid evolution.

Online since December 24, 2010


Letter 4 [2010]: Early large borings from a hardground of Floian-Dapingian age (Early and Middle Ordovician) in northeastern Estonia (Baltica), by Olev VINN & Mark A. WILSON.-
Format [HTML] or [PDF 330 KB]
Reference: [CG2010_L04]
DOI: 10.4267/2042/35594
Lang.: 

CG2010_L04_thumb Abstract:  Large plug- or slightly amphora-shaped borings have been found in the hardground marking the boundary between Early and Middle Ordovician rocks in northeastern Estonia. These borings cut large bioclasts of the trilobite Megistaspis and cannot be assigned with certainty to any known ichnotaxon. They indicate that the diversity of early borings may have been greater than was recognized previously.

Online since December 14, 2010


Letter 3 [2010]: Fossil Phoronida and their inferred ichnotaxa, by Christian C. EMIG.-
Format [HTML] or [PDF 779 KB]
Reference: [CG2010_L03]
DOI: 10.4267/2042/35531
Lang.: 

CG2010_L03_thumb Abstract:  Various ichnotaxa found in hard substrates are interpreted as "phoronid" trace fossils. Their records are briefly reviewed. An interpretation of Diorygma found in the shells of brachiopods is not compatible with phoronid morphology and anatomy. Criteria for the discrimination of phoronid burrows and borings from those of similar organisms from others are difficult to establish even when the evidence and conclusions made therefrom are sound.

Online since November 30, 2010


Article 7 [2010]: The evolution of ammonite associations during the Early Oxfordian (Mariae and Cordatum zones) in the Jura area (eastern France), by Rémi JARDAT.-
Format [HTML] or [PDF 2,174 KB]
Reference: [CG2010_A07]
DOI: 10.4267/2042/35492
Lang.: 

CG2010_A07_thumb Abstract:  The study of more than 40 sections in the "Creniceras renggeri marls" of the French Jura Range (Lower Oxfordian) has found:

  • a precise biochronostratigraphic subdivison of 16 successive populations or associations which appears to be stable over the whole geographic area concerned;
  • the correlation of these populations with the Lower Oxfordian zones of the GFÉJ (French Research Jurassic Group) and with those of southern England (Weymouth) and Poland (Cracow area);
  • an autecologic and synecologic analysis of Oxfordian ammonite associations in the Jura Mountains;
  • an interpretation of these faunas in terms of palaeo-depth and sequence stratigraphy units.

The main results of the study are the following:

  • identification of the Costicardia Subzone;
  • validation of the subdivision of the Mariae Zone established by Fortwengler and Marchand (1994), with a woodhamense horizon above a scarburgense horizon;
  • division of the woodhamense horizon into two units: the lower one is the woodhamense s.s. unit and the upper one includes abundant specimens of woodhamense var. normandiana Spath;
  • correlation of tectonic units on either side of the Salins fault and of some characteristics of the ammonite populations;
  • identification of five steps of changes in depth in the Jura area which may be interpreted as sequence stratigraphic units: a first episode of deepening during the period bounded by the scarburgense and praemartini horizons, an episode of stability bounded by the beginning and the end of the alphacordatum horizon, a slight regressive trend that lasted throughout the duration of the praecordatum horizon, a second episode of stability that persisted from the Bukowskii Subzone to the Costicardia Subzone, and a third deepening trend during the existence of the Cordatum Subzone.

Online since November 22, 2010


Article 6 [2010]: Biostratigraphic distribution of orbitolinids in the ammonite biozones (Urgonian platform of southeastern France). Part 1: Upper Hauterivian-lowermost Barremian, by Bernard CLAVEL, Robert BUSNARDO, Jean CHAROLLAIS, Marc André CONRAD & Bruno GRANIER.-
Format [HTML] or [PDF 34,646 KB]
Reference: [CG2010_A06]
DOI: 10.4267/2042/33369
Lang.: 

CG2010_A06_thumb Abstract:  The proposed biostratigraphic distribution of orbitolinids from the Upper Hauterivian and the lowermost Barremian of SE France is correlated with the ammonite biozonation. It is based on the detailed study of eight sections which delivered orbitolinids intercalated with or capped by levels with ammonites and, in some cases, echinids and dasycladales. Among the 24 species of orbitolinids present during that period, 3 are restricted to the Late Hauterivian: Praedictyorbitolina busnardoi, Paleodictyoconus beckerae and Valserina primitiva.

Online since August 27, 2010


Article 5 [2010]: Barremian-Aptian Dasycladalean algae, new and revisited, from the Tirgan Formation in the Kopet Dagh, NE Iran, by Morteza TAHERPOUR KHALIL ABAD, Marc André CONRAD, Ali Asghar ARYAEI Aryaei & Ali Reza ASHOURI.-
Format [HTML] or [PDF 6,671 KB]
Reference: [CG2010_A05]
DOI: 10.4267/2042/33368
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CG2010_A05_thumb Abstract:  Abundant, diversified algal assemblages comprising more than 25 species of Dasycladales are described from Barremian-Aptian limestone deposits of the Tirgan Formation in NE Iran. New species are described: one of them possibly belongs to a new endosporate genus, tentatively assigned the Triploporellaceae; two others, Clypeina ? sp. 1 and Rajkaella ? sp. 1, are left in open nomenclature. The widely distributed, locally abundant Montiella ? elitzae is revisited, because of the presence of a complete, exceptionally well preserved specimen. Yet to be demonstrated, the species is a junior synonym of Turkmenaria adducta Maslov, also originally described from the Kopet Dagh. Other species found in the Arkan section have already been reported from remote locations, primarily in Europe, in areas corresponding to the Northern and/or Southern Tethyan domains. Some of them are known only from the Hauterivian and/or the Barremian, excluding the Aptian, thus dating the lower part of the Arkan section as Barremian, but not excluding the Late Hauterivian.

Online since August 27, 2010


Article 4 [2010]: The Abiod at Ellès (Tunisia): stratigraphies, Campanian-Maastrichtian boundary, correlation, by Francis ROBASZYNSKI & Moncef MZOUGHI.-
Format [HTML] or [PDF 5,932 KB]
Reference: [CG2010_A04]
DOI: 10.4267/2042/33367
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CG2010_A04_thumb Abstract:  [The Abiod Formation at Ellès (Tunisia): tripartite lithology, biohorizons based on globotruncanids and ammonites, duration, location of Campanian-Maastrichtian boundary, correlation with Kalaat Senan and the Tercis (France) stratotype]
In central Tunisia near the village of Ellès is Wadi Ed Dam. There the Abiod Formation, underlain by the Kef marls and capped by the El Haria marls, crops out in an almost uninterrupted exposure about 286 m thick. In view of its possible use as a regional litho- and bio- stratigraphic reference section for the southern border of the Tunisian trough it is examined in detail here. Fossils studied include foraminifera (115 samples representing 6 micropaleontologic zones, see chart) and ammonites. The biohorizons established are based on the first (FO) or last occurrence (LO) of certain species of planktonic foraminifers in addition to the FO of already established foraminiferal zonal markers. Ammonite markers found include both the FO and LO of some forms, or just one or the other.
The location of the Campanian-Maastrichtian (Cp-Ma) boundary time line at Ellès is established by comparison with that determined at Kalaat-Senan and with that of the international stratotype of Tercis (France), ratified by the International Union of Geological Sciences.
At Kalaat-Senan the Cp-Ma boundary is set at the lower third of the upper indurated limestone bar of the Abiod Formation - the Ncham Member. Its location at Kalaat-Senan is based on the upper limit of occurrence of Nostoceras (Nostoceras) hyatti and Pseudokossmaticeras brandti together with the FO of Nostoceras magdadiae, a Maastrichtian ammonite. At Ellès several of these same markers are present, along with the respective planktonic foraminiferal zones.
The length in years of some lithologic units and paleontologic zones in the Upper Cretaceous succession of wadi Ed Dam was calculated using cyclostratigraphy. The Abiod Formation represents 13.2 Ma, the Radotruncana calcarata Zone 0.79 Ma, and the Nostoceras (Bostrychoceras) polyplocum Zone 0.97 Ma. A proposed subdivision of the Upper Campanian is recommended at the base of the Bostrychoceras Zone.
Li et alii's 1999 proposal for fixing the location of the Cp-Ma boundary at the top of a limestone bed in the El Haria marls is reviewed.

Online since August 27, 2010


Article 3 [2010]: Bucurella, a new genus of the Thyrsoporelleae (fossil Dasycladalean algae), by Bruno GRANIER.-
Format [HTML] or [PDF 2,462 KB]
Reference: [CG2010_A03]
DOI: 10.4267/2042/32425
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CG2010_A03_thumb Abstract:   A new genus, Bucurella, is described and figured; it is based on Macroporella espichelensis Deloffre et Ramalho, 1971, a taxon known only from the Late Jurassic. It is characterized by the presence of distinctive whorls, each with three thick and broad (fertile) ramifications. The lateral division formula is 1 F: 3 F: (3x2) F: (3x2x2) F = (1: 3: 6: 12); that is the primary ramification divides into three secondaries which in turn branch dichotomously into tertiaries and again into quaternaries. It and its descendant, Zergabriella, are assigned to the Tribe Thyrsoporelleae.

Online since May 31, 2010


Article 2 [2010]: Traces of explosive volcanism in the Pyrenean Campanian around the Campanian-Maastrichtian boundary type section at Tercis (SW France, N Spain). Biostratigraphy with emphasis on the foraminifer Radotruncana calcarata, by Gilles Serge ODIN.-
Format [HTML] or [PDF 6,809 KB]
Reference: [CG2010_A02]
DOI: 10.4267/2042/32424
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CG2010_A02_thumb Abstract:   Pyroclastic material including idiomorphic crystals of sanidine, biotite, and apatite, first identified in the type section at Tercis are contemporaneous with the Radotruncana calcarata (planktonic foraminifer) total range zone. A search was undertaken to define the palaeogeographical extent and to determine the importance of these remains of a previously unknown Campanian regional alkaline volcanic episode. A preliminary biostratigraphical search was carried out in the Tercis area and in the western Pyrenees followed by detailed micropalaeontological studies in southwestern France and northern Spain. The findings from five upper Campanian platform and flysch facies are reported in detail and deductions from three others are summarized. First, The microfaunal count of the boundary stratotype at Tercis has been increased by the use of acetolytic techniques to disaggregate indurated carbonates. So isolated tests of some key biostratigraphic markers are documented for the first time. The paucity in specimens of Radotruncana calcarata previously seen in thin sections from the type outcrop is not due to a scarcity of this particular taxon but to a general dearth of globotruncanids in the platform facies deposits of the Aturian Basin. The study shows that acetolysis multiplies the power of investigation of indurated limestones. Thus, the abundance and diversity of microproblematica discovered and studied in the stratotype section since 2006 has been confirmed and two new forms of incertae sedis are reported, one of which is called here Velafer ovatus. Today, 70 species of microproblematica are recognized at Tercis. These microproblematica allow a chronologic calibration of the deposits like or even more precise than those obtainable using ammonites or planktonic foraminifers. Sections sampled in the western Pyrenean flysch facies include the stratigraphic interval comprising the total range zone of Rd. calcarata for which we suggest here a duration of0.80 ±0.05 Ma. No microproblematica were found in these deep detrital facies. 

All sections reaching the Campanian-Maastrichtian boundary contain a Contusotruncana (foraminifer) of which the morphology, illustrated anew from 3 discrete sections, is consistent with that of the specimens identified at this level in the Tercis type-section; they were called C. contusa or C. contusa?/C. patelliformis? These micropalaeontological studies substantiate the choice of Tercis as the best section in the world for location of the stratotype of the Campanian-Maastrichtian stage boundary; they show again its striking regional and global correlative power thanks to the unique diversity of its biological record of the late Cretaceous. In addition, it justifies the choice of a boundary level selected using the near-coincidence of a variety of key events bracketting a guide-event; 12 were clustered around the mid-level 115.2 of the type section where the GSSP of the Campanian-Maastrichtian boundary has been recognized internationally. Consequently, the selected level does not depend on a unique "magic marker" with its inherent uncertainty caused by difficulty in identification and scarcity locally and in other localities and environments. This may well be the case for the guide-ammonite Pachydiscus neubergicus as commonly used as a marker of the Campanian-Maastrichtian boundary.

The biostratigraphical study precisely locates the pyroclastic material observed at Tercis as within the range of Rd. calcarata, immediately above the last occurrence of Tubellus hunzikeri, the first occurrences of Lucernellus aubouini and Aquilegiella varia, 3 microproblematica of which the distribution is well documented at Tercis. Previously reported evidences of volcanism at Tercis: the presence of kaolinite in the clay size fraction and of microcrystals of sanidine, biotite, zircon, apatite are supplemented here by the discovery of slightly calcic and sodic siliceous spherules with traces of magnesium, aluminum and potassium. Kaolinite and sanidine have also been found in contemporaneous levels at Peyrata, in the vicinity of the type section. Farther away in the flysch facies, the contemporaneous deposits contain pyroclastic biotite mica flakes, idiomorphic zircon crystals and, more rarely, apatite crystals of which the morphology is consistent with a volcanic origin. The presence of traces of a volcanic episode in Campanian levels representing about 1 Ma of deposition are thus confirmed but in the Pyrenees no information is available concerning the site of its origin. In fact, the explanations for the presence of the pyroclastic material involves two possibilities: either there was Campanian alkaline volcanic activity in the Pyrenees similar to that associated with subduction (which has not been identified and is not consistent with the accepted geodynamical model of the area) or the pyroclastic material comes from North America, distant some 5000 km. Such long distance transport would involve an west-east eolian conveyance of mm sized volcanic elements for 1 Ma (a hypothesis to our knowledge undocumented).

Online since May 31, 2010


Letter 2 [2010]: Hadrosaur remains in the Late Cretaceous marine sediments of Larcan (Petites Pyrenees, Haute-Garonne, France), by Michel BILOTTE, Yves LAURENT & Dominique TÉODORI.-
Format [HTML] or [PDF 1,166 KB]
Reference: [CG2010_L02]
DOI: 10.4267/2042/32428
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CG2010_L02_thumb Abstract:  The discovery of two hadrosaur fragments (maxilla and quadrate) in marine sediments of the end of the Cretaceous (uppermost Maastrichtian) is reported. Although this type of taphocoenosis is not exceptional for continental organisms, its situation at approximately 1 m under the iridium zone of the K/T boundary deserves to be emphasized.

Online since May 31, 2010


Article 1 [2010]: Problems in the identity of "Crioceras" barremense Kilian, 1895 (Ancyloceratida, Late Barremian), and their proposed resolution, by Didier BERT, Robert BUSNARDO, Gérard DELANOY & Stéphane BERSAC.-
Format [HTML] or [PDF 1,983 KB]
Reference: [CG2010_A01]
DOI: 10.4267/2042/32967
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CG2010_A01_thumb Abstract:  The study of "Crioceras" barremense Kilian was undertaken as a part of the revision of the Hemihoplitidae. This species was considered "classic" and has been used as the index of an Upper Barremian subzone; this usage raises a number of problems. The type specimen from Tyrol was a fragment described and illustrated by Uhlig as Crioceras sp. ind. aff. roemeri. This specimen could not be retrieved, and a topotype could not be collected. Our study revealed that there is both a biostratigraphic hiatus and important differences between conceptions of this species: (1) that ascribed Uhlig's type specimen (Upper Barremian, Tyrol), (2) Kilian's concept of the specimen he found and named "Crioceras" barremense (probably a Camereiceras from the uppermost levels of the Vandenheckei Subzone or from the basal Sartousiana subzone of the Nauvin site, southeastern France) and (3) current interpretations of authors, who often synonymize the type specimen with Gassendiceras alpinum (d'Orbigny), which occurs in the middle of the Vandenheckei Subzone. So there is a real confusion concerning the synonymy of "Crioceras" barremense. The age of Uhlig's type specimen is too imprecise and its preservation too fragmentary to be reliably identifiable, because the same morphology and ornamentation exist in several species of other genera. Therefore, we recommend the use of the species "Crioceras" barremense Kilian be avoided, in particular as an index, along with that of the genus Barrancyloceras Vermeulen for which "C." barremense is used as reference. Some species formerly assigned to this genus have been referred to the genus Gassendiceras Bert et alii. Consequently, we also recommend the Barremense auctorum Subzone be renamed the Alpinum Subzone (new) [index-species: Gassendiceras alpinum (d'Orbigny)], without changing its limits as currently defined. The lower limit of this subzone is indicated by the first occurrence of Gassendiceras alpinum (a new biohorizon, introduced here), a common, easily identifiable species with a well-defined stratigraphic range.

Online since April 4, 2010


Letter 1 [2010]: A pterosaur from the Toarcian (Early Jurassic) of the Ardennes (north-eastern France), by Eric BUFFETAUT, Bernard GIBOUT & Danielle DROUIN.-
Format [HTML] or [PDF 735 KB]
Reference: [CG2010_L01]
DOI: 10.4267/2042/32427
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CG2010_L01_thumb Abstract:  A pterosaur tibia-fibula is described from Toarcian shales ("Marne de Flize") near the city of Charleville-Mézières (Ardennes, northeastern France). The morphology of this element, especially the reduced fibula partially fused to the tibia, suggests that it belongs to the rhamphorhynchid Dorygnathus, which is well represented in the Toarcian Posidonienschiefer of Germany and has also been reported from the Toarcian of Nancy (eastern France).

Online since February 15, 2010


up2  

2009 (vol. 9) 

Article 10 [2009]: The Gargasian of Gargas (Vaucluse, SE France): Synthesis of field data and revision of the foraminiferal and ostracodal microfauna, by Michel MOULLADE, Guy TRONCHETTI & Jean-François BABINOT.-
Format [HTML] or [PDF 975 KB]
Reference: [CG2009_A10]
DOI: 10.4267/2042/30051
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CG2009_A10_thumb Abstract:  Because of urbanization the section at Gargas, historical stratotype of the Aptian stage and of the Gargasian substage, is no longer accessible. However, samples taken there in 1966 by one of us make feasible a reinterpretation of this series in the light of taxonomic and biostratigraphic data from a recent study of Aptian microfaunas from La Tuilière area, some 5 km away.
This new micropaleontologic interpretation shows that the historical section is truncated at its base : the lower (not lowermost) Gargasian is in quasi-direct contact with Urgonian limestones ; the uppermost (marly) Bedoulian, known to be present westward towards Le Chêne as well as at La Tuilière, is absent in the stratotype outcrop. In the samples from the stratotypic succession we have identified (bottom upward):
   • the upper part of the Praehedbergella luterbacheri zone and the Globigerinelloides ferreolensis zone,
   • the G. barri zone,
   • the beginning of the G. algerianus zone,
i.e. these zones comprise the major part of the lower Gargasian, the middle Gargasian and the transition to the upper Gargasian.
The upper part of the G. barri zone and the passage to the G. algerianus zone are in sandy marls of which the upper terms were said to have yielded ammonites of the "Clansayes horizon" (sensu ante). The microfauna does not resolve this apparent discrepancy, for its state of preservation degrades rapidly in the detrital levels, to the point of quasi-disappearance in sands overlying the Clansayesian auct. A comparison with the sector of Banon, only some 10 km away, led us to suggest that these sands cropping out at top of the Gargas Hill might be of Late Albian-Vraconnian age.

Online since December 31, 2009


Article 9 [2009]: Size variations of the vestibula of Krithe gnoma Do Carmo & Sanguinetti, 1999 (Ostracoda): a new procedure for their analysis, by Dermeval Aparecido D0 CARMO, Ricardo Piazza MEIRELES, Paulo Anselmo Ziani SUAREZ & Vinicius Moreira MELLO.-
Format [HTML] or [PDF 895 KB]
Reference: [CG2009_A09]
DOI: 10.4267/2042/30050
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CG2009_A09_thumb Abstract:  The species Krithe gnoma was described from Holocene sediments on the continental margin of Brazil, where it occurs on both shelf and slope. The shelf distribution of this species is restricted to those areas influenced by the Malvinas current between 32°11' and 22°31'S. K. gnoma was selected due to the excellent resolution of images of the anterior vestibule. So the range in size of the vestibula of this species was used to determine whether or not the dimensions of the anterior vestibule were to some degree related to amount of dissolved oxygen in the water at the sampling site. Female valves of the 7th and 8th instars were measured and their sizes and those of the anterior vestibule were compared. These valves and the reference carapace were collected at six localities in the southern shelf area. The anterior vestibule of right and left valves of the 7th instar and one of the 8th instar from discrete localities were measured. In the reference carapace, the larger left valve also has the larger vestibule. A gerontic 8th instar has valves larger than those of the previous instars, but its vestibula are smaller than those of the 7th instar. The vestibula of the left valves of the 7th instar collected at discrete localities showed consistent differences in size related to the oxygen content of the sampling site. The relationship between vestibule size and oxygen content is inversely proportional.However, the poor correlation factor (R2<<1) of these results are not precise enough to support Peypouquet's hypothesis. But the size of the vestibula of K. gnoma does show some degree of relationship to oxygen content. So it is important to measure the vestibula of species of Krithe using the procedure described here. Rigorous application of this procedure will eliminate the possibility of discrimination based on variations in size due to ontogeny and dimorphism leaving only those related to actual valve size. In any case, variations in the size of vestibula may have a phenotypic origin.

Online since December 31, 2009


Article 8 [2009]: Nummulus brattenburgensis and Crania craniolaris (Brachiopoda, Craniidae), by Christian C. EMIG.-
Format [HTML] or [PDF 1.590 KB]
Reference: [CG2009_A08]
DOI: 10.4267/2042/29780
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CG2009_A08_thumb Abstract:  The Brattingsborg pennies are mentioned in medieval texts dating from the middle of the first millennium and many popular medieval legends refer to their occurrence on Ivö Island in the Scania region (Sweden) as brattingsborgpenningar or in Latin as Nummulus brattenburgensis. Actually they are valves of the fossil brachiopod Crania craniolaris originally described by Linnaeus (1758) as Anomia craniolaris from the Upper Cretaceous. Later Retzius (1781) created the genus Crania based on these specimens from Ivö Island and on another species he described under Crania (now Isocrania) egnabergensis from Ignaberga in the Scania region. The scientific history of those two species is reviewed along with that of Danocrania tuberculata (Nilsson, 1826), formerly figured as Craniolites brattenburgicus, from the Danian of Scania. Two legends about these "pennies" are included.

Online since October 31, 2009


Memoir 3 [2009]: New data on the Middle-Upper Jurassic - Lower Cretaceous Charophytes and Ostracods from the Moroccan Atlas, by Pierre-Olivier MOJON, Hamid HADDOUMI & André CHARRIÈRE.-
Format [HTML] or [PDF 7,487 KB, plates with a coloured background] or [PDF 8,353 KB with black & white plates]
Reference: [CG2009_M03]
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CG2009_M03_thumb Abstract:  The Middle Jurassic-Lower Cretaceous continental "Red Beds" of the Moroccan Atlas have provided very interesting new taxa of charophytes and lacustrine ostracods: Aclistochara africana n.sp. (Bathonian), Feistiella atlantis n.sp. (Hauterivian-Lower Barremian), Cypridea suprajurassica n.sp., Cypridea mohandi n.sp. and Cypridea demnatensis n.sp. (Oxfordian ? - Kimmeridgian), Harbinia atlasica n.sp. (Hauterivian ? - Lower Barremian). Micropaleontological data obtained after 2002 contributed the following:
• In the central High-Atlas, discovery of Upper Jurassic charophytes and freshwater ostracods (Dictyoclavator ramalhoi, Porochara kimmeridgensis, Aclistochara bransoni, Cypridea suprajurassica, Cypridea mohandi, Cypridea demnatensis) evince a Barremian ingression, its restricted marine character attested by lagoonal-brackish water ostracods (Harbinia atlasica) and presumed marine ostracods Trachyleberididae (cf. Strigosocythere strigosa, Cythereis ? sp., Protocythere ? sp.) associated with well-developed gypsiferous evaporites.
• In the eastern High-Atlas, charophytes have been found at levels related to the Jurassic/Cretaceous boundary (Upper Tithonian–Berriasian Porochara maxima).
• In the non-marine Lower Cretaceous (Hauterivian ? - Barremian) of the central High-Atlas, mixed Eurasian e and Gondwanian g assemblages of charophytes: Globator (e) and Feistiella (g), and brackish-lacustrine ostracods: (Fabanella-Cetacella (e), Darwinula-Cypridea-Harbinia (e & g) and Salvadoriella-Petrobrasia-Reconcavona-Paracypridea (g), were discovered.
• Complementary data for the Lower Cretaceous charophyte biozonation (Upper Valanginian-Lower Barremian interval) with Globator hemiglobatoroides Mojon n.sp. (Cenozone M7a, NE-Spain) and Globator mutabilis (Cenozone M7b) from NE-Spain and Morocco (central High-Atlas) were obtained.
• In the Moroccan Atlas area several stages in the breaking up of Pangea and the opening of the Atlantic Ocean have been recognized. These dislocations took place mainly during Bathonian times but also involved portions of the Kimmeridgian and Barremian.

Online since October 31, 2009


Article 7 [2009]: Quick look cathodoluminescence analyses and their impact on the interpretation of carbonate reservoirs. Case study of mid-Jurassic oolitic reservoirs in the Paris Basin, by Bruno GRANIER & Christian STAFFELBACH.-
Format [HTML] or [PDF 716 KB]
Reference: [CG2009_A07]
DOI: 10.4267/2042/28795
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CG2009_A07_thumb Abstract:  Cathodoluminescence analyses on samples from Middle Jurassic oolitic limestones allow us to reconstruct the diagenetic history of these oil and gas reservoirs: a succession of events starting with the early, synsedimentary phases of marine cementation and ending with the addition of hydrocarbons to the reservoir. Constraints on the timing of events are derived from their calibration with the chronology of the well-known regional tectonic calendar. Fracturing, due first to the post-Pyrenean extension and then to the Alpine compression, led respectively in Oligocene times to a recharge of the aquifer and a correlative change in cementation, and in Miocene times to the addition of hydrocarbons into the same flow units, this last event blocking diagenesis, at least in the zone above the oil-water contact. Distributions of cements and residual porosity within sedimentary units without stratigraphic significance, called here "pseudo-parasequences", were for the most part inherited from the original depositional facies.

Online since September 30, 2009


Article 6 [2009]: The Paleocene and earliest Eocene foraminiferal Family Miscellaneidae: neither nummulitids nor rotaliids, by Lukas HOTTINGER.-
Format [HTML] or [PDF 27,417 KB]
Reference: [CG2009_A06]
DOI: 10.4267/2042/28794
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CG2009_A06_thumb Abstract:  The Miscellaneidae are divided into two groups of species: forms with a single intercameral foramen and forms with two or a row of multiple foramina. Ten taxa ascribed to this family are revised, amply illustrated and discussed considering both micro- and megalospheric generations. The Family Miscellaneidae is assigned to the Superfamily Nonionacea by reason of their planispiral-involute coiling combined with an interiomarginal position of the foramina. Their combined range covers SBZ zones 2-5 and an area comprising the Central and Western Neotethys including the Pyrenean Gulf. They do not reach the western shores of the Atlantic. Miscellanites meandrinus and Bolkarina aksarayi exhibit extreme morphological features, respectively meandrine alar extensions and expanse chambers. These features are of general interest for the comparative anatomy of the shells of the larger foraminifera in order to understand their biological significance.

Online since September 30, 2009


Article 5 [2009]: The ammonite fauna of the 'marls with ferruginous fossils' from the Niort region, France (Lower Oxfordian, Cordatum Zone, Cordatum Subzone), by Philippe QUEREILHAC, Didier MARCHAND, Rémi JARDAT, Alain BONNOT, Dominique FORTWENGLER & Philippe COURVILLE.-
Format [HTML] or [PDF 4,284 KB]
Reference: [CG2009_A05]
DOI: 10.4267/2042/28697
Lang.: 

CG2009_A05_thumb Abstract:  A new collection of ammonites from the 'marls with ferruginous ammonites' in the Niort region (France), previously studied by Grossouvre (1922), provides a large amount of biostratigraphic, paleoenvironmental and paleogeographic information. The fauna is dated Lower Oxfordian: Cordatum Zone, Cordatum Subzone, probably the lower part of it. In addition, it is unique in western Europe owing to: 1) the species found of which some appear to be known only in this deposit 2) by the extremely atypical domination of the couple Taramelliceras - Creniceras which represent 2/3 of the specimens. Furthermore, the aspect of the fauna strongly suggests that the habitat was a distal platform unknown in other European strata of the same age. A detailed description of the several species is given, sometimes accompanied by a new taxonomic interpretation.

Online since September 15, 2009


Memoir 2 [2009]: Subfamily Taramelliceratinae (Ammonitina, Haploceratoidea, Oppeliidae) from Middle and Upper Oxfordian strata (Plicatilis Zone, Vertebrale Subzone - Bimammatum Zone, Berrense Subzone) of N Vienne, France (submediterranean province), by Philippe QUEREILHAC.-
Format [HTML] or [PDF 17,578 KB]
Reference: [CG2009_M02]
DOI: 10.4267/2042/28698
Lang.: 

CG2009_M02_thumb Abstract:  In the area of northern Poitou studied Taramelliceratinae are present at every level except in the Schilli Subzone, itself possibly absent, and the Stenocycloides Subzone in which only Perisphinctidae and Trimarginites sp. occur. Although some species are known and cited in the literature often, they are figured infrequently or not at all: Taramelliceras (Taramelliceras) dentostriatum (Quenstedt), T. (T.) callicerum (Oppel), T. (Proscaphites) anar (Oppel). Here, the ranges of these species in the stratigraphic succession were determined through their association with other faunas in the same collections, using the presence or absence of known precise stratigraphic markers (for example: Neomorphoceras chapuisi (Oppel) = Transversarium Zone, Luciaeformis Subzone; Taramelliceras (? Taramelliceras) colleti (Lee) = Rotoides Subzone; "Epipeltoceras semimammatum" (Quenstedt) = Bimammatum Zone, "Berrense" Subzone, Semimammatum horizon) and/or the disappearance of species with longer ranges (for example: the disappearance of Neoprionoceras lautlingensis (Rollier) which is present in the Parandieri Subzone, but absent in the overlying Luciaeformis Subzone). The ranges of certain species that had been incorrectly located stratigraphically : T. (T.) dentostriatum (Quenstedt), T. (T.) callicerum (Oppel), T. (T.) externnodosum Dorn, have been restored to their true location as determined from their occurrences in the author's collections and in those of other collectors who had noted their stratigraphic relationships to other taxa.
It is recommended that the date of creation of the Luciaeformis Subzone and the Nectobrigensis, Luciaeformis and Subschilli horizons (Middle Oxfordian, Transversarium Zone) should be rectified. Currently, these are indicated as having been created in 1984. However, if the author's name, G. Melendez, is correct the date of their creation cannot have been 1984, the year in which the G. Melendez thesis was defended, for the manuscript was published only in 1989. It is also proposed that the Duongi horizon Melendez, 1989, be renamed as the Duongae horizon Melendez, 1989, because the index form, Perisphinctes (Dichotomoceras) duongi Melendez, 1989, is an ammonite species named to honor of A.N. Duong, a woman.
The study involved more than fifteen hundred individuals, all collected in the zone investigated. Only the most representative are figured here. The poor state of preservation of the ammonites (encrusted, often worn on one face, with the umbilicus not accessible) did not permit measurement (hence no table) except that of the diameter and sometimes the thickness. Previous studies of this subfamily or these species (Oppel, 1863; Quenstedt, 1887; Loriol, 1902; Lee, 1905; Dorn, 1931; Hölder, 1955) are old. References to this subfamily or its representatives in more recent works are only incidental and rarely include descriptions, drawing or photographs. The existence of many ammonites comprising homogeneous groups but without characteristics in common with known species justifies the creation of new species. Some microconchs have been definitely associated with a macroconch species. For others, a lack of material did not permit the establishment of such a direct link so they have been attached to the supposedly related species with the mention, "aff." (for "affinis"). Nevertheless, although described and figured, these forms remain in open nomenclature. There are some "groups" of ammonites with new characteristics that are here associated with a known species because the differences were not sufficient to create new ones; they are distinguished by "var." (for "variety"). There are also some that are referred to a previously known species because they were based only on a fragment (polymorphism?). In addition, in the zone studied the several taxa of this subfamily permit a relatively detailed stratigraphic breakdown because their existence is limited at a maximum to a subzone. However, an exception is the species Taramelliceras (Proscaphites) anar (Oppel, 1863) which ranges from the Antecedens Subzone through the Rotoides Subzone.

Online since September 15, 2009


Letter 3 [2009]: An additional hadrosaurid specimen (Dinosauria: Ornithischia) from the marine Maastrichtian deposits of the Maastricht area, by Eric BUFFETAUT.-
Format [HTML] or [PDF 730 KB]
Reference: [CG2009_L03]
DOI: 10.4267/2042/28153
Lang.: 

CG2009_L03_thumb Abstract:  An isolated dinosaur vertebra from the marine deposits of the Maastrichtian type area, near the city of Maastricht (The Netherlands), collected during the 19th century and kept in the palaeontological collection of the Museum für Naturkunde in Berlin, is described as a caudal vertebra of a hadrosaurid ornithopod. Although it cannot be identified with greater accuracy, this specimen is an addition to the still scanty, but growing, record of non-avian dinosaurs from the Maastrichtian type area. This record is heavily dominated by hadrosaurs, which probably reflects a real abundance of this group of dinosaurs in the late Maastrichtian of Europe.

Online since August 1, 2009


Letter 2 [2009]: Evidence of predation on the vertebra of a hadrosaurid dinosaur from the Upper Cretaceous (Campanian) of Coahuila, Mexico, by Héctor E. RIVERA-SYLVA, Eberhard FREY & José Rubén GUZMÁN-GUTIÉRREZ.-
Format [HTML] or [PDF 1,788 KB]
Reference: [CG2009_L02]
DOI: 10.4267/2042/28152
Lang.: 

CG2009_L02_thumb Abstract:  In sediments of the Aguja Formation (Late Cretaceous: Campanian) at La Salada in northern part of the state of Coahuila, Mexico, numerous fossils of vertebrates have been discovered including Hadrosauridae. One hadrosaur vertebra provides evidence of predation probably by a giant alligator Deinosuchus riograndensis.

Online since August 1, 2009


Article 4 [2009]: The IMAM case. Additional investigation of a micropaleontological fraud, by Bruno GRANIER, Monique FEIST, Edward HENNESSEY, Ioan BUCUR & Baba SENOWBARI-DARYAN.-
Format [HTML] or [PDF 1,916 KB]
Reference: [CG2009_A04]
DOI: 10.4267/2042/25073
Lang.: 

CG2009_A04_thumb Abstract:  Starting in 1996 and for almost a decade, M.M. Imam contributed to twelve papers published in international geological journals. These papers dealt with the micropaleontology and biostratigraphy of Cretaceous to Miocene series from Egypt and Libya. They were abundantly illustrated in order to support the author's findings and interpretations. However most photographic illustrations (189 at least) were fabricated with material lifted from the publications of other authors, commonly from localities or stratigraphic intervals other than those indicated by M.M. Imam.

Online since May 18, 2009


Article 3 [2009]: Uppermost Albian biostratigraphy and chronostratigraphy, by Robert W. SCOTT.-
Format [HTML] or [PDF 428 KB]
Reference: [CG2009_A03]
DOI: 10.4267/2042/24969
Lang.: 

CG2009_A03_thumb Abstract:  The Albian Stage is the highest chronostratigraphic unit of the Lower Cretaceous Series and underlies the Cenomanian Stage of the Upper Cretaceous Series. The Albian is divided into three substages, each of which is composed of two or three zones based on distinctive and phylogenetically related ammonite assemblages. The uppermost zone of the Upper Albian Substage, the Stoliczkaia dispar Zone, is found in many Western European condensed sections. The ammonite assemblage in the thin glauconitic sandstone near La Vraconne, Switzerland, was defined as the 'Vraconnian Stage' in 1868. However this concept has been little used and was abandoned in 1963 as part of the Cretaceous chronostratigraphic scale. A recent proposal to resurrect and redefine this stage is based on a number of criteria and very detailed and reliable stratigraphic data. A quantitative biostratigraphic analysis of the ammonite ranges in the key sections shows that the proposed subzones of the S. dispar Zone have discordant ranges. Furthermore, the utility of a 'Vraconnian Stage' between the Albian and Cenomanian stages is geographically limited and the concept embraces one of many depositional sequence cycles of the Albian. The reinstatement of a 'Vraconnian Stage' is not recommended.

Online since April 22, 2009


Article 2 [2009]: Pseudoshasticrioceras bersaci nov. sp. (Ammonoidea, Gassendiceratinae), and new ammonite biohorizon for the Upper Barremian of southeastern France, by Didier BERT & Gérard DELANOY.-
Format [HTML] or [PDF 1,7600 KB]
Reference: [CG2009_A02]
DOI: 10.4267/2042/23733
Lang.: 

CG2009_A02_thumb Abstract:  Research in the Feraudianus Subzone of the Sartousiana Zone of the Barremian stage led to the discovery of a new species of Pseudoshasticrioceras: P. bersaci nov. sp. Its study provides evidence concerning the developments of the latest Gassendiceratinae Bert et alii, 2006, and the relationship between the genus Pseudoshasticrioceras Delanoy, 1998, and Gassendiceras Bert et alii, 2006. In particular, this new species is derived from Pseudoshasticrioceras magnini (Delanoy, 1992) by a minor revision in the processes of ontogenesis (retardation of ornamentation - neoteny). However, the evolution towards Pseudoshasticrioceras autrani Delanoy, 1998, implies a "failure" in this process that may possibly be related to parallel changes in environmental conditions. On the other hand, the very closely defined stratigraphic position of Pseudoshasticrioceras bersaci nov. sp., and its position in the anagenetic lineage of Pseudoshasticrioceras, demonstrates its interest as a biostratigraphic marker: a new Bersaci Biohorizon is proposed; it is located between the Magnini and the Autrani biohorizons.

Online since April 4, 2009


Article 1 [2009]: Albian-Middle Turonian ostracodes from the Antsiranana region (northern Madagascar): systematics, palaeoecology and palaeobiogeography, by Jean-François BABINOT, Jean-Paul COLIN & Auran RANDRIANASOLO.-
Format [HTML] or [PDF 3,284 KB]
Reference: [CG2009_A01]
DOI: 10.4267/2042/23730
Lang.: 

CG2009_A01_thumb Abstract:  Ostracode associations from the Antsiranana region, formerly Diego-Suarez, in northern Madagascar have been studied at a taxonomic level. In the Albian-middle Turonian interval, 29 species belonging to 21 genera have been recognized, 10 new species, one new genus (Malagasyella) and a new sub-genus (Hemiglenocythere) have been erected. From a palaeoecological stand point, the succession of ostracode faunas shows a progressive shallowing trend, from basin-slope during Albian times to outer shelf during the Turonian. During these periods, the ostracode faunas of Madagascar show strong affinities with those of India (Rajasthan). This leads to a proposal for the existence of an indo-malagasy ostracode faunal province.

Online since April 4, 2009


Letter 1 [2009]: Serravallian (Miocene) nannofossils in Patagonia, Argentina, by Margarita SIMEONI.-
Format [HTML] or [PDF 689 KB]
Reference: [CG2009_L01]
DOI: 10.4267/2042/23731
Lang.: 

CG2009_L01_thumb Abstract:  For the first time, nannofossils found in the marine stratigraphic unit named "Patagoniano" which crops out at Cerro Chenque and Cerro Hermitte in southeastern Chubut, Argentina, are documented. They were recovered from pelitic levels in the lower part of coarsening-upward siliciclastic sedimentary sequences. The nannofossils are assigned in part to the Discoaster kugleri Zone NN7 (Martini, 1971) and CN5b (Bukry, 1971, 1973) thus allowing correlation of the productive levels with the Serravallian Stage (upper Middle Miocene).

Nota breve 1 [2009]: Nannofósiles del Serravalliano (Mioceno) en Patagonia, Argentina, de Margarita SIMEONI.-
Formato [HTML] o [PDF 689 KB]
Referencia: [CG2009_L01]
Idioma: 

 Resumen:  Se documenta el primer hallazgo de nannofósiles en el "Patagoniano", unidad estratigráfica marina aflorante en Cerro Chenque y Cerro Hermitte, al sudeste de Chubut, Argentina. Los nannofósiles fueron recuperados en niveles pelíticos inferiores de diferentes ciclos sedimentarios, grano-crecientes hacia la parte superior, formados por rocas siliciclásticas. Los nannofósiles pertenecen, en parte, a la Zona de Discoaster kugleri NN7 (Martini, 1971) and CN5b (Bukry, 1971, 1973) permitiendo la correlación de los niveles fértiles con el Piso Serravalliano (Mioceno Medio superior).

Online since March 31, 2009
En línea desde el 31 de Marzo de 2009


Memoir 1 [2009]: Mediterranean Neocomian belemnites, part 3: Valanginian-Hauterivian belemnites, by Nico M.M. JANSSEN.-
Format [HTML] or [PDF 2,898 KB]
Reference: [CG2009_M01]
DOI: 10.4267/2042/23732
Lang.: 

CG2009_M01_thumb Abstract:  The classical papers of Raspail (1829, 1830) and Duval-Jouve (1841) described a wide range of belemnite species, mainly from the Lower Cretaceous of the Castellane-Peyroules area (Alpes de Haute-Provence, France). The present work focuses mainly on the biostratigraphy of these previously described belemnite taxa for their stratigraphic relationships had not been determined precisely. Here, biostratigraphy is related to the lithologic successions and faunal associations (ammonites) of various outcrops in the area studied. Complementary data were obtained from the La Lagne, Les Allaves and Pas d'Escale sections (Alpes de Haute-Provence, France). And, in order to attain a better understanding of the stratigraphic distribution of Late Valanginian belemnites in condensed glauconitic deposits, these assemblages are compared with belemnites from deeper water successions in the Angles, Source de l'Asse de Moriez, Cheiron areas and those in the vicinity of La Charce and Vergol that are even deeper.

Online since March 31, 2009


up2  

2008 (vol. 8) 

Article 9 [2008]: Spirochetes and salt marsh microbial mat geochemistry: Implications for the fossil record, by Elizabeth A. STEPHENS, Olivier BRAISSANT & Pieter T. VISSCHER.-
Format [HTML] or [PDF 315 KB]
Reference: [CG2008_A09]
DOI: 10.4267/2042/20045
Lang.: 

CG2008_A09_thumb Abstract:  Microbial mats are synergistic microbial consortia through which major elements, including sulfur, are cycled due to microbial and geological processes. Depth profiles of pH, O2, sulfide, exopolymeric substances (EPS), and the rate of sulfate reduction were determined in an Oscillatoria sp. and Microcoleus-dominated marine microbial mat at the Great Sippewissett salt marsh, Massachusetts. In addition, measurements in spirochete enrichments and Spirochaetae litoralis cultures showed sulfide consumption during which polysulfides, thiosulfate, and presumably sulfate formed. These data suggest that spirochetes can play a role in the cycling of sulfur in these mats. The obligate to facultative anaerobic spirochetes may consume sulfide to remove oxygen. Furthermore, spirochetes may enhance preservation of microbial mats within the rock record by degrading EPS and producing low molecular weight organic compounds (LMWOC). Both sulfide oxidation (i.e., oxygen removal) and EPS degradation (i.e., production of LMW organic compounds) stimulate the activity of sulfate-reducing bacteria (SRB), which are responsible for the precipitation of calcium carbonate in most lithifying mats.

Online since December 10, 2008


Article 8 [2008]: On the history of the names Lingula, anatina, and on the confusion of the forms assigned them among the Brachiopoda, by Christian C. EMIG.-
Format [HTML] or [PDF 1,225 KB]
Reference: [CG2008_A08]
DOI: 10.4267/2042/20044
Lang.: 

CG2008_A08_thumb Abstract:  The The first descriptions of Lingula were made from then extant specimens by three famous French scientists: Bruguière, Cuvier, and Lamarck. The genus Lingula was created in 1791 (not 1797) by Bruguière and in 1801 Lamarck named the first species L. anatina, which was then studied by Cuvier (1802). In 1812 the first fossil lingulids were discovered in the Mesozoic and Palaeozoic strata of the U.K. and were referred to Lingula on the basis of similarity in the form of the shell. In the 1840's other linguliform brachiopods from the Palaeozoic were described. The similarity of the shell form of the extant Lingula and these fossils led Darwin in 1859 to create the description "living fossil" in his book "On the Origin of Species". Thereafter, this Darwinian concept became traditional in that Lingula was considered to lack morphological evolutionary changes. Although denounced as scientifically incorrect for more than two decades, the concept still remains in many books, publications and Web sites, perhaps a witness to palaeontological conservatism.

Online since December 10, 2008


Memoir 4 [2008]: Aptian and Albian Phylloceratids (Ammonoidea) from the Vocontian Basin (SE France), by Bernard JOLY & Michel DELAMETTE.-
Format [HTML] or [PDF 6,688 KB]
Reference: [CG2008_M04]
DOI: 10.4267/2042/19113
Lang.: 

CG2008_M04_thumb Extended English abstract:  More than 2,200 pyritized ammonites of the Superfamily Phylloceratatoidea have been collected in consonance with the scale of the ammonite zonation of the expanded Marnes Bleues Fm in the Vocontian Basin (SE France). This abundant material allows the description and the figuration (specimens and sutures) of 28 taxa of which 4 are new:

  • Phylloceras (Hypophylloceras) moriezense Sayn, 1920 subsp. tenuicostulata nov. Diagnosis: variant of P. (H.) moriezense distinguished by a subrectangular section of the whorl and a flattening of the sides less accentuated than on the typical form, with a very fine costulation that descends almost to the middle of the side (early late Aptian);
  • Phylloceras (Goretophylloceras) vocontium nov. sp. Diagnosis: thick shell, convex sides, rounded and compressed venter, maximum thickness of the whorl near the umbilicus, open umbilicus, constrictions at least at the beginning of the last whorl, oval whorl section, suture line of subgenus Goretophylloceras (mid middle Aptian to earliest Albian);
  • Salfeldiella (Gyrophyllites) falloti nov. sp. Diagnosis: shell with a finely costulate test, smooth internal mold, open umbilicus, nearly flat sides, rounded venter, subquadratic whorl section, proverse constrictions of the internal mold, radial constrictions in small specimens, a ventral sinus in the largest specimens, suture line like that of the genus Gyrophyllites (late Early Aptian to late Aptian);
  • Phyllopachyceras brehereti nov. sp. Diagnosis: thick shell, flat sides, venter flat or slightly convex, whorl quadratic in section, suture lines like those of the genus Phyllopachyceras with tetraphyllic spatulate elongated saddles (early mid-Aptian to early late Aptian).

Owing to the abundance of the Phylloceratoidea and the variations of specific diversity in 9 fossiliferous levels ranging in age from the late Early Aptian to the end of the Albian it is possible to identify 3 peaks of abundance:

  • peak 1 during the early mid-Aptian (base of the Martini zone),
  • peak 2 near the Aptian and Albian boundary, a few meters below the anoxic Paquier level,
  • peak 3 during the latest Albian (Blancheti zone).

Of these 3 peaks the first is the most important probably because the Vocontian Basin attained its maximum depth during this time. The peaks appear to be correlated with the maximum flooding intervals of depositional sequences. But high sea-levels were not always favourable for the Phylloceratoidea. The very fossiliferous Paquier level, although it took place during a high in sea-level, is characterised by the virtual absence of the deep-water ammonites, e.g. Phylloceratids, Tetragonids and Lytoceratids. This fact is explained by the presence of a deep-water anoxia. Another depletion of Phylloceratoidea in conjonction with a great abundance of Desmoceratid and Mortoniceratid ammonites and benthic fauna (Inoceramids Bivalves) occurred during the early Late Albian. At that time, the Vocontian area appears to have reached a minimal depth resulting from a pause in the rate of subsidence associated with an influx of siliciclastic material that attained the center of the basin.

After a last episode during the Early Cenomanian of the Vocontian Basin when the Phylloceratoidea occurred significant number, this group of ammonites shows a drastic decrease in abundance. This evolution is correlated with the filling of the basin from west to east, thus restricting the Phylloceratoidea and the other deep-water ammonites to a small eastern area (Leiostraca area of Thomel, 1965, 1980).

Online since September 28, 2008


Article 7 [2008]: Holostratigraphy of the Kahmah regional Series in Oman, Qatar, and the United Arab Emirates, by Bruno GRANIER.-
Format [HTML] or [PDF 2,154 KB]
Reference: [CG2008_A07]
DOI: 10.4267/2042/19112
Lang.: 

CG2008_A07_thumb Abstract:  The stratigraphic framework of the uppermost Jurassic - Lower Cretaceous interval of the Gulf area is revised using both historical and recently acquired paleontological (ammonites, calpionellids, foraminifers, 'calcareous' algae), sedimentological and sequential information. The Kahmah regional Series ranging in age from Late Tithonian to Gargasian (= middle Aptian) times is subdivided into regional stages, named from bottom to top: Rayda (with two substages, Bu Haseer and Belbazem), Salil, Zakum, Lekhwair, Kharaib, Hawar, and Shu'aiba. The Kahmah rests either on strata representing the Habshan regional Stage, which is the last term of the Sahtan regional Series (locally absent due to a stratigraphic hiatus in basinal areas), or on much older strata; it is followed either by the Bab regional Stage (locally absent due to a stratigraphic hiatus on platform areas), or by the Sabsab regional Substage (the lowermost part of the Nahr Umr regional Stage), both of which are assigned the Wasi'a regional Series. The Kahmah succession (as well as those of the Sahtan below and the Wasi'a above) is discontinuous, i.e. punctuated by sedimentary hiatuses due to forced regressions, some of significant importance (in the Zakum or in the Bab, and those bounding the Hawar and the Shu'aiba).

Online since September 28, 2008


Article 7 [2008] - an extra video: Holostratigraphy of the Kahmah regional Series in Oman, Qatar, and the United Arab Emirates, by Bruno GRANIER.-
The video of Fig. 18 lien revisited


Click on image to play the video file (flv = 5,029 KB)

Online since May 22, 2010


Letter 3 [2008]: About the stratigraphic position of the Lower Aptian Roloboceras hambrovi (Ammonoidea) level, by Pierre ROPOLO, Michel MOULLADE, Gabriel CONTE & Guy TRONCHETTI.-
Format [HTML] or [PDF 180 KB]
Reference: [CG2008_L03]
DOI: 10.4267/2042/18124
Lang.: 

CG2008_L03_thumb Abstract:  In the stratotype of the Lower Aptian substage the position of the assemblage that includes Roloboceras spp. and Megatyloceras spp. has been clearly established as being in the middle part of the upper Bedoulian. Some authors have erected this horizon as a subzone, or even a zone, with R. hambrovi as species-index. In other areas (southern England, eastern Spain, the Ardèche in southeastern France), where taphonomic conditions are not always as favourable as they are in the stratotype, the level at which this assemblage occurs seems to be confined to the upper part of the lower Bedoulian. Various hypotheses are considered in an attempt to explain this divergence.

Online since August 27, 2008


Memoir 3 [2008]: The Douvilleiceratidae (Ammonoidea) of the Lower Aptian historical stratotype area at Cassis-La Bédoule (SE France), by Pierre ROPOLO, Gabriel CONTE, Michel MOULLADE, Guy TRONCHETTI & Roland GONNET.-
Format [HTML] or [PDF 6,688 KB]
Reference: [CG2008_M03]
DOI: 10.4267/2042/18125
Lang.: 

CG2008_M03_thumb Abstract:  Recent biostratigraphic research in the marly limestones of the Cassis-La Bédoule area (SE France) provided a rich macrofauna of Douvilleiceratidae Parona & Bonarelli, 1897. From the uppermost Barremian (Pseudocrioceras waagenoides Subzone) to the middle Aptian (Parahoplites melchioris Zone), specimens of Procheloniceras, Cheloniceras, Roloboceras, Megatyloceras and Epicheloniceras were collected in succession. In this paper we describe the various genera and species from this material and delimit precisely their stratigraphic positions. Our study shows that each genus or subgenus characterizes a discrete stratigraphic interval. In addition, the Cheloniceras meyendorffi (upper Bedoulian), Epicheloniceras debile, Epicheloniceras gracile, and Epicheloniceras buxtorfi (Gargasian = middle Aptian) subzones, originally defined in England by Casey (1961a), are identified for the first time in the Lower Aptian stratotypic area of Cassis-La Bédoule.

 Erratum:  The photo of a specimen of Megatyloceras ricordeanum (d'Orbigny) from the private collection of Cyril Baudouin and coming from the locality of Le Teil (Ardèche) is figured in the memoir of P. Ropolo et alii (2008, Pl. 08, fig. 3 lien) instead of and in place of a specimen collected at La Bédoule. The first author (P.R.) tells us that it was because of an error in the labeling of his photographic archives that this unfortunate substitution could occur. He asks not just the owner of the photograph and the ammonite, Cyril Baudouin, but also his co-authors and the editors and readers of Carnets to be good enough to pardon him for this unintentional error.
We remind you that the whole of the material illustrated in this memoir is already deposited or is being deposited, is catalogued or is being catalogued in the Museum of Paleontology of the University of Provence (Aix-Marseilles 1), St. Charles Campus.

Format [HTML] ou [PDF 76 KB]

Online since August 27, 2008


Article 6 [2008]: Middle Jurassic to Lower Cretaceous continental deposits from eastern High Atlas (Morocco): successive paleoenvironments and paleogeographic significance, by Hamid HADDOUMI, André CHARRIÈRE, Bernard ANDREU & Pierre-Olivier MOJON.-
Format [HTML] or [PDF 2,069 KB]
Reference: [CG2008_A06]
DOI: 10.4267/2042/18122
Lang.: 

CG2008_A06_thumb Abstract:  In the eastern High Atlas (Morocco), continental "Red Beds" overlying the last marine deposits of Jurassic age consist of three main lithostratigraphic units: the Anoual Formation, the Ksar Metlili Formation and the Dekkar Group, bounded by two sharp sedimentary discontinuities. The Anoual Formation is a fluvial dominated deltaic plain deposit. It is followed by a final marine transgression of Early Bathonian age. The Ksar Metlili Formation found only in some subsident areas represents a renewal of fluvio-deltaic environments with a flora of Late Tithonian-Early Berriasian charophytes. The Dekkar Group occupies a larger area of sedimentation, its limits overlap the whole domain. From bottom to top, the succession indicates the existence of three paleoenvironments: alluvial fans deposits locally associated with Barremian?-Aptian lacustrine sediments containing charophytes and ostracods, alluvial plains deposits and finally, marine coastal to brackish plains deposits of the Cenomanian.
After the closure of the Jurassic Atlasic marine trough, the eastern Atlasic "Red Beds" were deposited in response to three main geodynamic events:
   • the filling of the Atlasic trough with very thick deposits in subsiding areas linked to tectonic rifting during the Early Bathonian;
   • the emergence of this area caused a hiatus in sedimentation involving strata ranging in age from Bathonian to Barremian?-Aptian. However, continental sediments are preserved in some onshore geomorphological depressions at the Jurassic/Cretaceous boundary;
   • the opening of new basins, continental during the Barremian?-Aptian, that became marine during the Late Cenomanian as the result of Cenomanian-Turonian transgression.
A comparison of the succession of events recorded in different parts of the Atlasic belts allows reconstruction of the three phases of paleogeographic evolution in these southern Tethyan areas during Middle Jurassic to Late Cretaceous times.

Online since August 1, 2008


Letter 2 [2008]: Zonation by ammonites and foraminifers of the Vraconnian-Turonian interval: A comparison of the Boreal and Tethyan domains (NW Europe / Central Tunisia), by Francis AMÉDRO & Francis ROBASZYNSKI.-
Format [HTML] or [PDF 144 KB]
Reference: [CG2008_L02]
DOI: 10.4267/2042/17066
Lang.:  

CG2008_L02_thumb Abstract:  Since the end of the 19th century the interval comprising the uppermost Upper Albian, the Cenomamian, the Turonian and the basal Coniacian has been subdivided, first into ammonite zones, then, beginning in the middle of the 20th century, into zones of planktonic foraminifera. These two groups, one macrofossil, the other microfossil, are particularly effective for bio-chronostratigraphy thanks to their rapid rates of evolution. But differences in the faunal makeup between the Boreal domain (northwestern Europe) and the Tethyan domain (Mediterranean) have for a long time hindered precise correlation of the two domains. Today, in a time interval covering about 16 million years, there are 29 ammonite zones in the Tethyan domain versus 24 in the Boreal one, of which 16 are common to both domains. For the planktonic foraminifera the Tethyan domain has 11 zones, the Boreal domain 10, with 7 in common.

Online since May 17, 2008


Memoir 2 [2008]: Support for a Vraconnian Stage between the Albian sensu stricto and the Cenomanian (Cretaceous System), by Francis AMÉDRO.-
Format [HTML] or [PDF 8,921 KB]
Reference: [CG2008_M02]
DOI: 10.4267/2042/17063
Lang.: 

CG2008_M02_thumb Abstract:  The geological scale for the middle Cretaceous currently used throughout the world was proposed by Alcide d'Orbigny in the XIXth century between the years 1842 and 1847 and establishes the succession of stages as Albian, Cenomanian and Turonian. In 1868 Renevier proposed that a supplemental chronostratigraphic division be intercalated between the Albian and the Cenomanian: the Vraconnian stage. This term was not generally accepted and after a period when it was referred to by Breistroffer (1936) as a substage constituting the upper part of the Albian, as an equivalent of the Stoliczkaia dispar ammonite Zone, its abandonment was "recommended" by the Conference on the Lower Cretaceous held in Lyon in 1963. The conditions that led to this "decision" will be discussed herein.
Historically, for almost a century the Vraconnian was studied only in the condensed levels of the platform where ammonites are abundant, but the succession is thin and not mappable. The type section of the Vraconnian in the Vaud canton of Switzerland is only 2 meters thick. In France the situation is the same in the northern Alps, in most of central Europe, in Russia, in the Crimea, and as far as the Caspian sea.
The examination of a certain number of sections located in other parts of the world: in the southeastern basin of France (Salazac, Marcoule, Mont-Risou), in the Anglo-Paris basin (Folkestone, Merstham, Grandpré), in the Mons basin (Harchies, Strépy-Thieu), at the southern edge of the Tethys in central Tunisia (Kaalat Senan), in Madagascar (Diégo Suarez) and North America in California (Dry Creek) demonstrates, however, that in a number of regions of the globe the sedimentary record of the Vraconnian is sometimes rather considerable, often much more important than that of the Albian sensu stricto.
In addition, the Vraconnian represents a very important eustatic event between an Albian transgression and the great Cenomanian transgression (third order cycle and the peak of transgression in a second order cycle). It involves a period of rapid ecologic expansion both as regards the macrofauna (ammonites in particular) and microfauna (planktonic foraminifera). These are the main reasons why a rehabilitation of the Vraconnian as a true stage is proposed here.

Online since May 17, 2008


Article 5 [2008]: Pseudoperisphinctinae (Ammonitina, Perisphinctidae) from the Leckenbyi horizon (Upper Callovian, Athleta zone) of Montreuil-Bellay (Maine-et-Loire, France) and description of a new species, Choffatia isabellae, by Alain BONNOT, Pierre-Yves BOURSICOT, Patrice FERCHAUD & Didier MARCHAND.-
Format [HTML] or [PDF 2,045 KB]
Reference: [CG2008_A05]
DOI: 10.4267/2042/16929
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CG2008_A05_thumb Abstract:  Many outcrops exposing the Mid-Callovian/Upper Callovian boundary have been found near Montreuil-Bellay (Maine-et-Loire). The lowermost bed of the Upper Callovian has been dated as the Leckenbyi horizon. It contains an abundant ammonite fauna (3125 specimens), in which Perisphinctidae make up just over half of the specimens. In company with reasonably well-known species such as Pseudopeltoceras leckenbyi (Bean), Orionoides pseudorion (Waagen), Subgrossouvria famulum (Bean) and S. crassa Gérard et Contaut, occurs a species, previously unknown, which is described in this article. Choffatia isabellae n. sp. differs markedly from contemporary Perisphinctidae, for it is distinguished by : 1) a long, smooth juvenile stage, 2) weakly developed ribbing, 3) the absence of parabolic ornamentation and 4) a high frequency of constrictions. As this species is unknown in the fauna of the uppermost Middle Callovian, along with many other species, including Peltoceras marysae Bonnot et alii, it must have colonised the northwestern part of the European platform via the southern margin of the Tethys during the transgressive interval which started at the beginning of the Late Callovian. This new species appears abruptly at the base of the Leckenbyi horizon, reaches its acme in the middle of the horizon, where it probably represents half of the Perisphinctidae, before becoming rare in the upper part of the horizon, then very rare in the Athleta horizon.

Online since April 17, 2008


Memoir 1 [2008]: Description and illustration of forty-four gilianelles (microproblematica) and ten other microproblematica of the Cretaceous of the stratotype section at Tercis (Campanian-Maastrichtian boundary), South-West France, by Gilles Serge ODIN.-
Format [HTML] or [PDF 15.672 KB] / pages 45-75 with a coloured background [PDF 3,477 KB]
Reference: [CG2008_M01]
DOI: 10.4267/2042/16746
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CG2008_M01_thumb Abstract:   Following acetolysis, microproblematica were collected from indurated carbonates sampled from the stratotype section of the Campanian-Maastrichtian boundary at Tercis (Landes, France). 44 taxa of the gilianelles group (microproblematica probably pertaining to the Protista, Protozoans, Rhizopods) as well as ten other microproblematica were discriminated. To document the taxa in this paper 281 scanning electronic microscope images and 183 optical microscope images are presented. The gilianelles encompass 36 species, and 8 subspecies referred to 15 genera of which 14 are new. The new genera are: Tercensella, Azymella, Numismella, Aturella, Scutellella, Corniculum, Caccabella, Orculiella, Pennigerella, Corbella, Aquilegiella, Pocillella, Coraliella, Obbella. Among the other microproblematica, nine species and one subspecies are proposed; they are referred to 7 new genera: Globulella, Piperella, Vasculum, Lucernellus, Cimicellus, Tubella, Pilella. This first general view uses normal taxonomic criteria to recognize and define a group of microfossils of which the identity and the consistency of occurrence are herewith established using the morphological characters of the body of the test, the presence and development of the expansions attached to that body, and its ornamentation. The use of these criteria in an ordered manner suggests that a rigorous taxonomic collocation is feasible, needing only a few other observations before becoming a formal classification. The statigraphic distribution of the taxa provides a means for establishment of a remarkable tool for relative dating in the stratotype section and its immediate vicinity ; microproblematica allow the sequence to be subdivided into intervals of deposition on the order of 0.1 Ma, a length of time shorter than the intervals obtained using the many microfossil or macrofossil groups previously employed to calibrate the stratotype. The Campanian-Maastrichtian boundary is within the limits of the genus Aturella lineage in the basal portion of the range of Aturella edentula.

Online since March 22, 2008
(Supplement online since March 27, 2008)


Article 4 [2008]: Diagenetic rejuvenation of raised coral reefs and precision of dating. The contribution of the Red Sea reefs to the question of reliability of the Uranium-series datings of middle to late Pleistocene key reef-terraces of the world, by Jean-Claude PLAZIAT, Jean-Louis REYSS, Abdelmajid CHOUKRI & Charlotte CAZALA.-
Format [HTML] or [PDF 2,228 KB]
Reference: [CG2008_A04]
DOI: 10.4267/2042/16743
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CG2008_A04_thumb Abstract:  This paper is a general review of the dating of reefs on the coasts of the Red Sea, including those of Egypt, Jordan, Sudan, Eritrea, Saudi Arabia and Djibouti. New methods of sampling and dating (U/Th) already tested on the reefs and associate deposits of the African coast of Egypt have demonstrated that processes of rejuvenation shown to exist in the best-preserved corals are attributable to the diagenesis of the organic material in their bio-minerals, thus justifying a revision of a great many datings of corals supposedly younger or older than the age assigned to the high-level isotopic substage (δ18O) MIS 5.5 (= 5e). During this late Pleistocene substage, a rapid lowering of sea level, short and limited to about ten meters, was detected and associated with a glacio-eustatic episode of global influence. A comparison of these Middle East reef chronologies with those of New Guinea, Australia and the western Atlantic that are referred only with difficulty to the δ18O global sea-level curves, casts doubt on the reliability of many regional reconstructions. Moreover the most "classic" reef chronologies, more or less out-of-phase with global isotopic records calls for a reexamination of the chronologic basis of the reference curves derived from marine isotopic data.

Online since March 22, 2008


Article 3 [2008]: New biohorizons and proposal for a revision of the ammonite biozonation of the Upper Barremian of southeastern France, by Didier BERT, Gérard DELANOY & Stéphane BERSAC.-
Format [HTML] or [PDF 346 KB]
Reference: [CG2008_A03]
DOI: 10.4267/2042/16737
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CG2008_A03_thumb Abstract:  New biohorizons and proposal for a revision of the ammonite biozonation of the Upper Barremian of southeastern France.- A new ammonite biozonal scheme is proposed for the Upper Barremian of southeastern France. It takes into account faunal changes, sequence stratigraphy and historical data. Four new biohorizons are proposed. At present, three (formerly six) are accepted for the Upper Barremian: the Vandenheckei, Sartousiana and Giraudi biozones. The first contains three subzones, the Uhligi (current status discussed), the Sayni and the Barremense subzones, and two new biohorizons, the Marchandi and Breistrofferi biohorizons (top of the Barremense Subzone). The Sartousiana Biozone now includes the Limentinus, Provincialis and Feraudianus subzones. This last one lost its status of biozone because of paleontologic and stratigraphic arguments. Six biohorizons are recognized in the Sartousiana Biozone: the Limentinus, Provincialis, Casanovai, Feraudianus, Magnini and Autrani biohorizons. The Giraudi Biozone includes the Giraudi, Sarasini and Waagenoides subzones and the Giraudi, Emerici and Puzosianum biohorizons.

Online since March 20, 2008


Letter 1 [2008]: Characterisation of the organic matter of upper Bedoulian and lower Gargasian strata in the historical stratotypes (Apt and Cassis-la-Bédoule areas, SE France), by François BAUDIN, Michel MOULLADE & Guy TRONCHETTI.-
Format [HTML] or [PDF 180 KB]
Reference: [CG2008_L01]
DOI: 10.4267/2042/14860
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CG2008_L01_thumb Abstract:  The Total Organic Carbon (TOC) content of the Gargasian strata studied in their historical stratotype area is rather low (0.3% on average). Only a few levels show TOC values approaching 1.2%. This small amount of preserved organic matter, associated with low hydrogen index values (10 to 115 mg hydrocarbons/g TOC), argues for deposition in fully oxic conditions. This organic content is a mixture of land-derived organic particles and deeply oxidized marine organic matter. The organic flux was strongly diluted by the autochthonous carbonate input.

Online since February 4, 2008


Article 2 [2008]: New micropalaeontological studies on the type section of the Campanian-Maastrichtian at Tercis (SW France): new ostracodes obtained using acetolysis, by Bernard ANDREU & Gilles Serge ODIN.-
Format [HTML] or [PDF 2,490 KB]
Reference: [CG2008_A02]
DOI: 10.4267/2042/14857
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CG2008_A02_thumb Abstract:  Through the use of acetolysis new micropalaeontological studies on the type section of the Campanian-Maastrichtian boundary at Tercis (SW France) we obtained additional information on ostracodes. Acetolysis on hard carbonates levels of the Tercis quarry found 22 species in addition to those of the studies published in 2001. Today, 75 species are recognized: they represent 34 known genera, and 4 currently unidentified. Small species usually rare of the genera Aversovalva, Bythoceratina and Eucytherura were collected. All of the assemblages (of both genera and species) are characteristic of a Campanian- Maastrichtian open carbonate platform environment.

Online since February 4, 2008


Article 1 [2008]: Planktonic and benthic foraminiferal assemblages and biostratigraphy of the uppermost Bedoulian and lower Gargasian of La Tuilière - St-Saturnin-lès-Apt (area of the Aptian stratotype, Vaucluse, SE France), by Michel MOULLADE, Guy TRONCHETTI & Jean-Pierre BELLIER.-
Format [HTML] or [PDF 7,370 KB]
Reference: [CG2008_A01]
DOI: 10.4267/2042/14699
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CG2008_A01_thumb Abstract:  Research on the Bedoulian and Gargasian of the Cassis-La Bédoule (Bouches du Rhône, SE France) area is extended, by a study of four overlapping sections in the stratotypic area of the Aptian stage in the hamlet of La Tuilière (commune of Saint-Saturnin-lès-Apt, Vaucluse, SE France). This new information permitted a detailed analysis of upper Bedoulian and lower Gargasian benthic (30 taxa) and planktonic (15 taxa) foraminiferal assemblages. Here we describe, illustrate and give the ranges and distribution of the most significant forms, and call attention to several benthic and planktonic species that may serve as extra-regional markers.
The study of the planktonics in these expanded and continuous sections made it possible to strengthen the zonation which had been established in the Lower Aptian stratotype of Cassis-La Bédoule, i.e. a succession of five zones (cabri, luterbacheri, ferreolensis, barri, algerianus); this zonal scheme is improved by the addition of a horizon with Globigerinelloides ferreolensis heptacameratus nov. subsp., which straddles the boundary between the luterbacheri and ferreolensis zones. We also show the temporal quasi-coincidence of: 1) the top of the Furcata ammonite Zone, 2) the lithological change named "change of color" and 3) a triple micropaleontological datum (FAD of Praehedbergella luterbacheri, LAD of Protocythere bedoulensis and Lenticulina cf. nodosa) of which the importance in the stratotype of Cassis-La Bédoule had already been pointed out. All these data may be valuable in the definition of the Bedoulian-Gargasian boundary.
Within the luterbacheri Zone of the early Gargasian, an episode probably of volcanic origin that we interpret as the equivalent of the Van Gogh Level (initially detected in the Vocontian domain), is marked by a strong crisis in the diversity of epibenthic and planktonic foraminifers, as well as in that of the ostracodes.
From a paleoecological and paleobiogeographical point of view, a comparison of the benthic and planktonic foraminiferal assemblages of La Tuilière with those of neighbouring areas reveals specific features related to paleodepth and shows affinities which appear to be closer with the microfaunas of certain boreal areas (e.g. northern Germany) than with the Tethysian realm.

Online since January 28, 2008


up2  

2007 (vol. 7) 

Article 7 [2007]: Facies development during late Early–Middle Cambrian (Tayan Member, Burj Formation) transgression in the Dead Sea Rift valley, Jordan, by Olaf ELICKI.-
Format [HTML] or [PDF 1,120 KB]
Reference: [CG2007_A07]
DOI: 10.4267/2042/9717
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CG2007_A07_thumb Abstract:  The transgressive Tayan Member of the upper Lower to Middle Cambrian Burj Formation (Jordan) has been investigated in several localities of the Dead Sea Rift valley, Jordan. The lower portion of this member consists of low-energy siliciclastics with indications of temporary, early pedogenetic processes, pointing to some stagnation during transgression. The upper portion of the member was deposited under higher energy conditions. Stromatolites, desiccation cracks, halite-pseudomorphs, laminated dolostones, and tepees, together with ripples, mud-clasts and scours point to a shallow intertidal to supratidal sabkha-related environment in a climate of tropical to subtropical aridity.
The fossil content of the Tayan Member consists exclusively of trace fossils. Simple endobentic, worm-like r-strategists are common in some horizons. For the first time, Treptichnus pedum has been reported from Jordan where it was found near the base of this member. The markedly reduced biodiversity together with sedimentological data led to the interpretation of a strongly stressed, paleoecologically unstable habitat.
Regional comparisons with high-energy transgressive environments laid down at the same time show that the main factors controlling facies development and the migration of facies belts are (1) the topography of the flooded surface and of the hinterland (mainly with only a local effect), (2) the configuration of the coast (local effect), (3) the rate of subsidence and transgression (local to regional effects), and (4) climate (large regional effects). The combination and overlap of these factors controlled facies gradients and may explain special differences between the facies of the Jordanian and those of the near-by Israeli transgressive deposits on the one hand, but, also the obvious general similarity of Lower to Middle Cambrian transgressive successions in the Middle East and the Mediterranean part of Gondwana on the other hand.

Online since November 1, 2007


Article 6 [2007]: Revision of the foraminiferal genus Globoreticulina Rahaghi, 1978 and of its associated fauna of larger foraminifera from the late Middle Eocene of Iran, by Lukas HOTTINGER.-
Format [HTML] or [PDF 7,274 KB]
Reference: [CG2007_A06]
DOI: 10.4267/2042/9213
Lang.: 

Test a new tool available from the page "Plate cross-comparison" (click, drag and drop)

CG2007_A06_thumb Abstract:  The definition of the type species of the genus Globoreticulina Rahaghi, 1978, G. iranica Rahaghi, 1978, is emended and its age discussed in relation to those of 17 associated taxa of larger foraminifera, all from restricted shallow environments. These taxa represent porcelaneous groups of spiroline habit including Rhabdorites malatyaensis, archaiasines (Archaias operculiniformis and A. diyarbakirensis), agglutinated conicals (Coskinolina and Dictyoconus) and some rotaliids (Medocia and others). These taxa were revised where necessary and their biostratigraphic ranges discussed. In addition to the establishment of a new subfamily of the Alveolinidae, the Malatyninae, the following new Linnaean names are introduced in order to conform with the revisions: Austrotrillina eocaenica n. sp., Neotaberina neaniconica n. gen. n. sp., Neorhipidionina spiralis n. gen. n. sp., Penarchaias n. gen. and Rotaliconus persicus n. gen. n. sp. The species Praerhapydionina huberi Henson is transferred to the genus Haymanella Sirel and the genus Praearchaias Sirel is suppressed. The age of the type level of Globoreticulina iranica is interpreted to be SBZ 18 (Late Bartonian) according to the available local data but the possibility that its stratigraphic position is actually level SBZ 17 or SBZ16 can not be excluded with certainty.

Online since September 25, 2007


Article 5 [2007]: The upper Bedoulian and lower Gargasian Ostracoda of the Aptian stratotype: Taxonomy and biostratigraphic correlation, by Jean-François BABINOT, Michel MOULLADE & Guy TRONCHETTI.-
Format [HTML] or [PDF 4,263 KB] / pages 8-9 in A3-sized pages [PDF 85 KB]
Reference : [CG2007_A05]
DOI: 10.4267/2042/8877
Lang. : 
Reference : [CG2007_A05 (fr)]
DOI: 10.4267/2042/8878
Lang. : 

 Abstract:  In the vicinity of Saint-Saturnin-lès-Apt (Vaucluse, SE France), which is included in the area of the historic Aptian stratotype of Apt-Gargas, are four sections in a succession that permits the study in a very detailed and continuous way of the last beds of the upper Bedoulian and those of the lower Gargasian. The Ostracod content of the microfauna is relatively important and in a satisfactory state of preservation. 46 species have been indexed of which three are new: Cytherella circumrugosa nov. sp., Cytherelloidea bedouliana nov. sp. and Parexophthalmocythere (Parexophthalmocythere) sp.
Until the present day, our comprehension of this group of microfossils in this stratigraphic interval was very fragmentary, not just in the Apt region but also in the Bedoulian historic stratotype area (Cassis-la Bédoule). This new study made it possible to determine a good number of species not previously reported in the stratotypes, to refine the generic status of many forms and to place some of them in open nomenclature.
The completion of a chronologic distribution chart collated with a recently published foraminiferal zonation (Cabri, Luterbacheri and Ferreolensis zones) shows very clearly the bipartite distribution of a good part of the Ostracod fauna. Accordingly, two ensembles are recognized, one at the end of the upper Bedoulian (index species Protocythere bedoulensis), the other characterizing the lower Gargasian, identified by the appearance and development of Parataxodonta inornata. The two groups are sharply separated by an episode of impoverished microfaunas at the base of the Gargasian.

Online since July 25, 2007


Article 4 [2007]: Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific, by Michael KNAPPERTSBUCH.-
Format [HTML] or [PDF 1,851 KB]
Reference: [CG2007_A04]
DOI: 10.4267/2042/8455
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 Abstract:  Variability in the test of Globorotalia menardii during the past 8 million years has been investigated at DSDP Site 502A (Caribbean Sea) and DSDP Site 503A (Eastern Equatorial Pacific). Measurements were made of spire height (∂x), maximum diameter (∂y), the tangent angles of the upper and lower peripheral keels (Φ1, Φ2, respectively), the number of chambers in the final whorl, and the area of the silhouette in keel view. Four morphotypes alpha, beta, gamma, and delta were distinguished. Morphotype alpha was found in strata ranging in age from the Late Miocene through the Holocene. It shows a continuous increase in ∂x and ∂y until the Late Pleistocene. During and after the final closure of the ancient Central American Seaway (between 2.4 Ma and 1.8 Ma) there was a rapid increase in the area of the test in keel view. At the Caribbean Sea site, morphotype beta evolved during the past 0.22 Ma. It is less inflated than alpha and has a more delicate test. In the morphospace of ∂x vs. ∂y, morphotypes alpha and beta can be distinguished by a separation line ∂y = 3.2 * ∂x - 160 (∂x and ∂y in µm). Plots of morphotype alpha are below that line, those of beta are above it. Morphotype alpha is taken to be Globorotalia menardii menardii Parker, Jones & Brady (1865) and includes G. menardii 'A' Bolli (1970). Morphotype beta is identified as G. menardii cultrata (d'Orbigny). Morphotypes gamma and delta are extinct Upper Miocene to Pliocene forms which evolved from morphotype alpha. They have a narrower Φ1 angle and more chambers (≥7) than morphotype alpha commonly with 5 to 6 chambers (7 in transitional forms). In contemporaneous samples morphotype delta can be distinguished from gamma by a smaller value of Φ1 and 8 or more chambers in the final whorl. Morphotype gamma is taken to be G. limbata (Fornasini, 1902) and includes the junior synonym G. menardii 'B' Bolli (1970). Morphotype delta is G. multicamerata Cushman & Jarvis (1930). With the exception of the Late Pleistocene development of G. menardii cultrataonly in the Caribbean the morphological changes of G. menardii at DSDP Sites 502A and 503A are similar. The development from the ancestral G. menardii menardii of the G. limbata - G. multicamerata lineage during the Pliocene and of G. menardii cultrata during the Late Pleistocene suggests responses at the two sites to a changing palaeoceanography during and after the formation of the Isthmus of Panama.

Online since July 2, 2007


Article 3 [2007]: Fluctuations of sea-water chemistry during Gargasian (Middle Aptian) time. Data from trace-element content (Mg, Sr, Mn, Fe) in hemipelagic carbonates from La Marcouline Quarry (Cassis, SE France), by Maurice RENARD, Marc de RAFÉLIS, Laurent EMMANUEL, Catherine BELTRAN, Michel MOULLADE, & Guy TRONCHETTI.-
Format [HTML] or [PDF 1,165 KB]
Reference: [CG2007_A03]
DOI: 10.4267/2042/8454
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 Abstract:  In the Lower Aptian historical stratotype area (Cassis-La Bédoule, SE France), a geochemical study of the Gargasian (Middle Aptian) marl-limestone alternations of the La Marcouline quarry complements data already obtained from Bedoulian (Early Aptian) sediments there. Nannoconids are the main carbonate producers in both limestones and marls. Although diagenetic minerals, such as ankerite (2.5%) are present in small amounts, the trace-element content of bulk carbonate is very close to that of Nannoconus spp. so geochemical sequences can be defined. The long-term evolution of trace-element content was not affected by diagenetic processes, variations in carbonate mineralogy, or a change of carbonate producers. An increase of around 500 ppm in the strontium content of bulk carbonate occurs between the base of the Cabri zone (late Bedoulian) and the Algerianus zone (late Gargasian). This evolution is linked to fluctuations in seawater Sr/Ca ratios caused by variability in the influx of hydrothermal and river waters, by changes in the ratio of aragonite/calcite production and by shifts in sea level. The eustatic sequence Aptian 4, its parasequences and its key surfaces (sequence boundaries, maximum flooding surface) are clearly reflected in the evolution of the bulk-carbonate contents of manganese.

Online since July 2, 2007


Article 2 [2007]: The Gargasian (Middle Aptian) of La Marcouline section at Cassis-La Bédoule (SE France): Stable isotope record and orbital cyclicity, by Wolfgang KUHNT & Michel MOULLADE.-
Format [HTML] or [PDF 485 KB]
Reference: [CG2007_A02]
DOI: 10.4267/2042/8044
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 Abstract:  Bulk rock stable isotope analysis of La Marcouline section (Cassis-La Bédoule area, SE France) revealed a general trend of decreasing δ13C and δ18O values from the bottom to the top of the section. The decrease in δ13C values reflects a global trend in Middle Aptian times, namely a return to pre-excursion values of δ13C values following a major, positive excursion in the Early Aptian, which is a reflection of the Oceanic Anoxic Event (OAE) 1a.
Power spectra of the bedding rhythms suggest that precessional and long eccentricity cycles of the Milankovitch band controlled the deposition of marl-limestone bundles. This can be interpreted as the result of a forcing by insolation at low latitudes which resulted in a monsoon-controlled precipitation pattern, that in turn induced the deposition of clay-rich beds. Conversely, limestone beds were formed in periods of dryer climate. Higher sea-surface productivity during wet periods may have been caused by an increase in continental runoff and a consequent enhancement in the delivery of nutrients to epicontinental basins.
An orbital cyclicity in the sedimentary patterns in La Marcouline section provides the opportunity to calibrate the duration of the well-established G. ferreolensis foraminiferal Zone with that of orbital chronology. The G. ferreolensis Zone at Cassis-La Bédoule spans 33 precessional cycles and its duration is thus estimated to be approximately 760  ka. This length of time is significantly shorter than the estimates of published timescales for this zone and thus may be an argument for proposing that the Gargasian substage is significantly shorter than its currently accepted range.

Online since May 24, 2007


Memoir 2 [2007]: Relations between the northern and southern margins of the Tethys ocean during the Cretaceous period, edited by Luc G. BULOT, Serge FERRY & Danièle GROSHENY.-
Format [HTML] or [PDF 4,951 KB]
Reference: [CG2007_M02]
DOI: 10.4267/2042/8029

 Abstract:   The theme of the 2006 meeting of the Groupe Français du Crétacé (GFC) was on a comparison of the northern and southern margins of the Tethyan ocean during the nearly 80 million year span of the Cretaceous period, a time when this large, meander-edged seaway was closed progressively by the movement of two major tectonic plates. Consequently, during this slow closure sedimentary successions near the northern and southern shores of the Tethys provide ideal sites for testing a number of hypotheses. One of these is the degree of correlativity between "events" in tracts far distant from one another. The "events" could be paleontologic (faunal renewal vs. migration), sedimentologic (are depositional sequences and specific lithologies such as black shale or phosphates on either shore coeval?), eustatic vs. tectonic. On November 27-28, 2006, thirty earth scientists met in the École des Mines in Paris to discuss these matters. Thirteen communications were presented, eleven of which as abstracts or extended abstracts comprise this special publication by "Carnets".

1- Robaszynski F., Amédro F., González-Donoso J.M. & Linares D. (2007).- Les bioévénements de la limite Albien (Vraconnien) - Cénomanien aux marges nord et sud de la Téthys (S.E. de la France et Tunisie centrale) [Bioevents at the Albian (Vraconnian) - Cenomanian boundary at the North and South margins of the Tethyan Ocean (SE France and Central Tunisia)].
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2- Courville P. (2007).- Échanges et colonisations fauniques (Ammonitina) entre Téthys et Atlantique sud au Crétacé supérieur : voies atlantiques ou sahariennes ? [Late Cretaceous faunal exchange and colonization (Ammonitina) between the Tethys and the South Atlantic: Atlantic or Saharan routes?].
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3- Westermann S., Föllmi K.B., Matera V. & Adatte T. (2007).- Phosphorus and trace-metal records during Cretaceous oceanic anoxic events: Example of the Early Aptian OAE in the western Tethys [Évolution de la concentration du phosphore et des métaux-traces durant les événements anoxiques du Crétacé inférieur : exemple de l'événement de l'Aptien inférieur (OAE 1a) dans la Téthys occidentale].
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4- Jammes S., Manatschal G. & Ghienne J.-F. (2007).- L'évolution tectono-sédimentaire du système "Golfe de Gascogne/Pyrénées Occidentales" au Crétacé inférieur : un nouveau regard [The tectonic and sedimentary evolution of the Bay of Biscay/Western Pyrenees during the Early Cretaceous : a new point of view].
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5- Bardet N., Houssaye A., Pereda Suberbiola X. & Rage J.-C. (2007).- The marine squamates (reptiles) from the Cenomanian-Turonian of the Tethys: a noteworthy radiation [Les squamates (reptiles) marins du Cénomanien-Turonien de la Téthys : une radiation remarquable].
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6- Yans J., Masure E., Dejax J., Pons D. & Amédro F. (2007).- Influences boréales dans le bassin de Mons (Belgique) à l'Albien [Boreal influences in the Mons basin (Belgium) during the Albian].
Lang.: 

7- Granier B. (2007).- On the track of a major trans-Tethyan discontinuity [Sur la piste d'une discontinuité majeure trans-Téthys].
Lang.: 

8- Ferry S., Merran Y., Grosheny D. & Mroueh M. (2007).- The Cretaceous of Lebanon in the Middle East (Levant) context [Le Crétacé du Liban dans le cadre du Moyen-Orient (Levant)].
Lang.:  

9- Grosheny D., Chikhi-Aouimeur F., Ferry S., Jati M. , Herkat M., Atrops F., Redjimi W. & Benkerouf F. (2007).- The Cenomanian-Turonian of the Saharan Atlas (Algeria) [Le Cénomanien-Turonien de l'Atlas saharien (Algérie)].
Lang.:  

10- Bulot L.G. (2007).- Endémisme et cosmopolitisme des faunes d'ammonites de la plaque arabique au Crétacé moyen (Aptien - Turonien) [Endemism vs. cosmopolitanism of the ammonite faunas from the Arabian plate during mid-Cretaceous times (Aptian – Turonian)].
Lang.: 

11- Bulot L.G. & Ferry S. (2007).- La discontinuité albienne à l'échelle globale et ses implications paléobiogéographiques et biostratigraphiques [The Albian unconformity at a global scale and its palaeobiogeographic and biostratigraphic implications].
Lang.: 

Online since May 15, 2007


Letter 1 [2007]: Parsimony analysis of endemicity of enchodontoid fishes from the Cenomanian, by Hilda Maria Andrade da SILVA & Valéria GALLO.-
Format [HTML] or [PDF 111 KB]
Reference: [CG2007_L01]
DOI: 10.4267/2042/7146
Lang.: 

 Abstract:  Parsimony analysis of endemicity was applied to analyze the distribution of enchodontoid fishes occurring strictly in the Cenomanian. The analysis was carried out using the computer program PAUP* 4.0b10, based on a data matrix built with 17 taxa and 12 areas. The rooting was made on an hypothetical all-zero outgroup. Applying the exact algorithm branch and bound, 47 trees were obtained with 26 steps, a consistency index of 0.73, and a retention index of 0.50. The topology found with a majority rule consensus was: [(Mexico) + (United States) + (Morocco + Italy) + (Lebanon + Israel) + (Italy-Slovenia) + (Brazil)] + (D.R. Congo) + (Sweden) + (Germany) + (England). The procedure delimited two areas of endemism in the Tethys Ocean. They are Morocco and southern Italy and Lebanon and Israel. The area of endemism formed by Morocco + Italy represents the North African region of the Tethys Ocean, and that formed by Lebanon + Israel is in the mid-Tethyan Ocean. Our results are in partial agreement with the patterns of geographical distribution of certain invertebrate biota.

 Corrigendum:  The fossil locality Lesina referred to in this paper as being in Italy is in fact in Croatia: Lesina is the former  name of  an island (Hvar). This correction does not affect the conclusions of the paper.

Online since April 4, 2007


Memoir 1 [2007]: Recent advances in palynology, edited by Philippe STEEMANS & Emmanuelle JAVAUX.-
Format [HTML] or [PDF 5,762 KB]
Reference: [CG2007_M01]
DOI: 10.4267/2042/7042

 Abstract:   A set of 11 abstracts and short papers (extended abstracts) of presentations given at a meeting organized by the NFSR Working Group, "Micropaléontologie végétale et Palynologie (MVP)", held on May 24, 2006 at the University of Liège, Belgium. Most contributions are available only in English.

1- Breuer P., Filatoff J. & Steemans P. (2007).- Some considerations on Devonian miospore taxonomy.
Lang.: 

2- Breuer P., Dislaire G., Filatoff J., Pirard E. & Steemans P. (2007).- A classification of spores by support vectors based on an analysis of their ornament spatial distribution – An application to Emsian miospores from Saudi Arabia.
Lang.: 

3- Dejax J., Dumax É., Damblon F. & Yans J. (2007).- Palynology of Baudour Clays Formation (Mons Basin, Belgium): correlation within the "stratotypic" Wealden.
Lang.: 

4- Gerards T., Yans J. & Gerrienne P. (2007).- Quelques implications paléoclimatiques de l'observation de bois fossiles du Wealdien du bassin de Mons (Belgique)
Résultats préliminaires.
Lang.: 

5- Grey K. (2007).- Advances in Ediacaran biostratigraphy in Australia.
Lang.: 

6- Javaux E.J. (2007).- Patterns of diversification in early eukaryotes.
Lang.: 

7- Prestianni C., Streel M., Thorez J. & Gerrienne P. (2007).- Strud: old quarry, new discoveries. Preliminary report.
Lang.: 

8- Steemans P. & Breuer P. (2007).- PalyWeb: A palynomorph database project on the web.
Lang.: 

9- Streel M., Renson V. & Vleeschouwer F. de (2007).- Palynological and geochemical data in peat sediments alongside an old (Roman or Merovingian) paved road in the Hautes-Fagnes.
Lang.: 

10- Vanmeirhaeghe J. (2007).- Chitinozoans of the lower Llanvirn Huy and the middle Caradoc Sart-Bernard formations (Middle to Upper Ordovician): implications for the stratigraphy of the Condroz Inlier (Belgium).
Lang.: 

11- Ville de Goyet F. de, Breuer P., Gerrienne P., Prestianni C., Streel M. &  Steemans P. (2007).- Middle Devonian (Givetian) megaspores from Belgium (Ronquières) and Libya (A1-69 borehole).
Lang.: 

Online since March 22, 2007


Article 1 [2007]: Environmental changes during marl-limestone formation: evidence from the Gargasian (Middle Aptian) of La Marcouline Quarry (Cassis, SE France), by Catherine BELTRAN, Marc de RAFÉLIS, Maurice RENARD, Michel MOULLADE & Guy TRONCHETTI.-
Format [HTML] or [PDF 646 KB]
Reference: [CG2007_A01]
DOI: 10.4267/2042/6828
Lang.: 

 Abstract:  Limestone-marl alternations are usually interpreted to reflect cyclic paleoenvironmental fluctuations linked to Milankovitch-scale climate variations. However, the impact of diagenesis on lithological differentiation can be overprinted on the primary signal.
In order to evaluate environmental variations during the deposition of the Gargasian hemipelagic limestone-marl alternations from the "La Marcouline" quarry (SE France), we have applied a multi-discipline approach (carbonate geochemistry, micropaleontology and mineralogy). The work uses of a method of granulometric separation of the main carbonate particles which (1) allows the characterization and quantification of the compositions of the carbonate phases of both lithologies and (2) gives access to the geochemical signatures of similar carbonate (bio-) particles in each lithology.
The quantifications show that micarb constitutes a significant portion (around 40 per cent) of the sediments. Their geochemical signatures indicate that most of them were formed by fine fragmentation of nannoconid tests. Based on these interpretations, our results indicate that nannoconids are the major constituents of both the marly limestone and the marl layers and that both lithologies are similar in composition.
The coccolith assemblages (mainly Watznaueria spp.) of the limestone and marl layers are similar and equally well-preserved. Changes in oxygen and carbon isotopic ratios express cyclic fertility and salinity/temperature variations in surface waters. The marls indicate higher fertility and lower salinity (or higher temperature) conditions than those denoted by the marly limestones.
Although diagenesis has not altered these rhythmites no strong evidence has been found for linking classical processes such as dilution or productivity cycles to the composition of the sediments (carbonate constituents and clay mineralogy).
This study demonstrates that La Marcouline succession has retained, as recorded by geochemical proxy, its primary environmental variations. Nevertheless, the homogeneity in both lithotypes of sedimentological parameters (clay mineralogy, sediment composition, ...) seems to indicate that these fluctuations did not affect the ecosystem strongly enough to cause marked differences in the composition of marls and marly-limestones.

Online since February 27, 2007


up2  

2006 (vol. 6) 

Article 5 [2006]: New micropalaeontological studies on the stratotype of the Campanian-Maastrichtian boundary at Tercis (SW France): the gilianelles (microproblematica) extracted through acetolysis, by Gilles Serge ODIN & Alexandre LETHIERS.-
Format [HTML] or [PDF 4,212 KB]
Reference: [CG2006_A05]
DOI: 10.4267/2042/6697
Lang.:  

 Abstract:  The Campanian-Maastrichtian stratotype section at Tercis (SW France) consists mainly of hard calcareous levels. Their treatment using acetolysis left residues among which for the first time well-preserved free microfossils were obtained (These levels had been studied previously only through thin sections). Within these residues, a wealth of calcareous shells of unknown affinity (incertae sedis) occur. These previously undescribed fossils are documented herein with photographs and drawings. Optical observations are synthesised in computer assisted drawings which depict 36 discrete forms. Scanning electron microscopy documented the nannostructures of these tests which led to the recognition of 30 forms with a common organisation and nannostructure. These are the microproblematica group called "gilianelles". The remaining six forms of incertae sedis do not share the same characteristics. According to morphological observations, a planktonic existence is inferred for most of the incertae sedis. The simple organisation and small size of the gilianelles suggest that they may represent a new Order of Rhizopod Protozoans. Their stratigraphical distribution has been established in the stratotype section of the "Grande Carrière" at Tercis (SW France). This distribution shows an extraordinary rate of turn-over with some taxa having a range of less than 1 Ma.

Online since December 14, 2006


Article 4 [2006]: Schmidtites celatus (Obolida, Brachiopoda) from the "Obolus sands" (Upper Cambrian - Lower Ordovician) of Estonia, by Christian C. EMIG.-
Format [HTML] or [PDF 801 KB]
Reference: [CG2006_A04]
DOI: 10.4267/2042/5837
Lang.: 

 Abstract:  Large collections of the brachiopod obolid Schmidtites celatus have been gathered from Upper Cambrian-Lower Ordovician strata in four northern Estonian localities. The morphological features and the taxonomic characters of the genus and of the single species representing it are re-described and illustrated. New diagnoses are proposed based on characters of the shell and morphological traits that permit Schmidtites celatus to be compared with and distinguished from the other obolid genera occurring in the same samples or areas, i.e. Ungula ingrica, Oepikites, and Obolus apollinis which now includes specimens formerly described as Ungula convexa. Schmidtites celatus differs from them mainly in the arrangement of its musculature.

Online since September 21, 2006


Article 3 [2006]: Are the green algae (phylum Viridiplantae) two billion years old?, by Bernard TEYSSÈDRE.-
Format [HTML] or [PDF 303 KB]
Reference: [CG2006_A03]
DOI: 10.4267/2042/5836
Lang.: 

 Abstract:  In his book, Life on a young planet, A.H. Knoll states that the first documented fossils of green algae date back 750 Ma. However, according to B. Teyssèdre's book, La vie invisible, they are much older. Using a method which combines paleontology and molecular phylogeny, this paper is an inquiry into the Precambrian fossils of some "acritarchs" and of a primitive clade of green algae, the Pyramimonadales. A paraphyletic group of unicellular green algae, named "Prasinophyceae", is represented at Thule (Greenland) ca. 1200 Ma by several morphotypes of the monophyletic Pyramimonadales, including Tasmanites and Pterospermella that are akin to algae still living today. These two, and others, probably had forerunners going back 1450 / 1550 Ma. Some acritarchs that may represent Pyramimonadales producing "phycomas" which split open for dehiscence were confusingly included in the polyphyletic pseudo-taxon "Leiosphaeridia" and are possibly already present at Chuanlinggou, China, ca. 1730 Ma. Many acritarchs that Timofeev obtained by acid maceration of Russian samples dated between 1800 and 2000 Ma were probably unicellular Chlorophyta which synthesized algaenans or other biopolymers resistant to acetolysis. Living Prasinophyceae are undoubtedly green algae (Viridiplantae). Thus, if Prasinophyceae fossils go back certainly to 1200 Ma, probably to 1500 Ma and possibly to 1730 Ma, then the ancestor of green algae (Chlorophyta and Streptophyta) probably separated from the ancestor of red algae (Rhodophyta) as early as 2000 Ma.

Online since September 19, 2006


Memoir 2 [2006]: Illustrated glossary of terms used in foraminiferal research, by Lukas HOTTINGER.-
Format [HTML] or [ PDF Text 739 KB + PDF Figs. 2-27 8,827 KB + PDF Figs. 28-46 7,391 KB + PDF Figs. 47-68 6,805 KB + PDF Figs. 69-83 6,454 KB]
Reference: [CG2006_M02]
DOI: 10.4267/2042/5832
Lang.: 

 Summary:  An illustrated glossary of terms used in the analysis of the shells of recent and fossil foraminifera supplemented by a rigorous selection of terms that facilitate an understanding of their biology and their use in ecology and biostratigraphy. The glossary includes some 650 entries illustrated by 83 - often composite – figures many of which are stereographs or 3D models. A taxonomic index lists the 140 taxa illustrated.

Online since September 8, 2006


Fig. 83 lien revisited

Online since August 2, 2007


Letter 2 [2006]: Ankylosaurid (Dinosauria: Thyreophora) osteoderms from the Upper Cretaceous Cerro del Pueblo Formation of Coahuila, Mexico, by Héctor E. RIVERA-SYLVA & Belinda ESPINOSA-CHÁVEZ.-
Format [HTML] or [PDF 617 KB]
Reference: [CG2006_L02]
DOI: 10.4267/2042/4741
Lang.: 

 Abstract:  Ankylosaurian dinosaur osteoderms have been discovered in the southeastern part of the State of Coahuila, Mexico, in the township of General Cepeda, in the locality known as El Palmar. The osteoderms were collected from rocks that had been correlated to the Cerro del Pueblo Formation (Late Cretaceous: Campanian) of the Difunta Group. The fossil material includes four dermal scutes and three associated fragments that at present cannot be identified. This is the first description of ostoederms and ankylosaurian material from Coahuila.

Online since May 11, 2006


Memoir 1 [2006]: The Deshayesitidae STOYANOV, 1949 (Ammonoidea) of the Aptian historical stratotype region at Cassis-La Bédoule (SE France), by Pierre ROPOLO, Michel MOULLADE, Roland GONNET, Gabriel CONTE & Guy TRONCHETTI.-
Format [HTML] or [PDF 15,159 KB]
Reference: [CG2006_M01]
DOI: 10.4267/2042/4744
Lang.: 

 Abstract:   One of the significant results of the multidisciplinary investigations carried out during recent years in the Lower Aptian historical stratotype of the Cassis-La Bédoule region (South-Eastern France) was a proposal to update the local Upper Barremian/Lower Aptian ammonite biozonation in order to be more consistent with the standard Mediterranean zonal subdivisions. So the lower and upper boundaries of the Lower Aptian (= Bedoulian substage of most French authors) as well as the boundaries of four biozones (Paradeshayesites tuarkyricus, P. weissi, Deshayesites deshayesi, Dufrenoyia furcata zones) and two subzones (Roloboceras hambrovi and Paradeshayesites grandis subzones) were identified and formally defined in the stratotype. However, to support this zonal scheme additional descriptions and illustrations of the ammonites collected bed by bed in the several sections studied were still required. In this paper we describe the members of the most significant ammonite family found in the Lower Aptian of Cassis-La Bédoule, i.e. the Deshayesitidae, and delimit precisely their stratigraphic positions. As regards zonation, we have replaced the index ammonite of the earliest Bedoulian Zone, i.e. Paradeshayesites tuarkyricus (BOGDANOVA, 1983), by Paradeshayesites oglanlensis (BOGDANOVA, 1983), and re-established the Pseudocrioceras waagenoides Zone as a subzone.

 Corrigendum:  There is an error in the labeling of Plate 8 in the above Memoir.

Consequently, the above plate caption:
Fig. 2.- Deshayesites evolvens LUPPOV, 1952 (Abm311), Les Fourniers section, bed 115. P. weissi Zone.
Fig. 3.- Deshayesites sp. gr. spathi/normani CASEY, 1964 (ABR340), Les Fourniers section, bed 111. P. weissi Zone.

Should read as follows:
Fig. 2.- Deshayesites sp. gr. spathi/normani CASEY, 1964 (ABR340), Les Fourniers section, bed 111. P. weissi Zone.
Fig. 3.- Deshayesites evolvens LUPPOV, 1952 (Abm311), Les Fourniers section, bed 115. P. weissi Zone.

Online since May 11, 2006


Article 2 [2006]: Decastronema kotori gen. nov., comb. nov.: a mat-forming cyanobacterium on Cretaceous carbonate platforms and its modern counterparts, by Stjepko GOLUBIC, Rajka RADOIČIĆ & Lee SEONG-JOO.-
Format [HTML] or [PDF 1,061 KB]
Reference: [CG2006_A02]
DOI: 10.4267/2042/4674
Lang.: 

 Abstract:  The fossil renamed here was first described in 1959 as Aeolisaccus kotori Radoičić, a new species of a problematic fossil worm, Aeolisaccus Elliott. In 1975 De Castro recognized the true relationships of this microbial fossil: a cyanobacterium related closely to the modern genus Scytonema. The fossil is common in the sediments of the Mesozoic carbonate platforms of southern Europe. This contribution confirmed De Castro's interpretation, determined, using the high resolution of the SEM, the extent to which these fossils have preserved their original architecture, and investigated their presumed modern counterparts among the abundant mat-forming species of Scytonema on the intertidal flats of Andros Island, a part of the Bahama carbonate platform. The systematic affinities of the fossil and the environments it inhabited were reconstructed by comparing the morphology of the fossils to that of their modern counterparts, along with their respective sedimentary contexts. Based on these comparisons, we conclude that the organism lived in a peritidal environment and was buried and fossilized in the shallow waters of an ancient carbonate platform. A formal transfer of the fossil to a new genus of fossil cyanobacteria thereby designated as Decastronema gen. nov. is proposed, honoring the contribution of Prof. Piero De Castro to paleontology.

Online since March 15, 2006


Article 1 [2006]: Microbiofacies analysis of Cambrian offshore carbonates from Sardinia (Italy): environment reconstruction and development of a drowning carbonate platform, by Olaf ELICKI.-
Format [HTML] or [PDF 1,558 KB] or [PDF 1,592 KB - A3-sized pages 10-11]
Reference: [CG2006_A01]
DOI: 10.4267/2042/4567
Lang.: 

 Abstract:   The Campo Pisano Formation of southwestern Sardinia is represented by an offshore carbonate succession spanning the latest Early to late Middle Cambrian. Paleogeographically, the fauna is characteristic of western Perigondwana, and indicates faunal relations to France, Spain, and Turkey. Microfaunal paleoecology reflects drowning of an isolated carbonate platform at tropical latitudes. Sessile epibenthic filter feeders dominate at the base, succeeded upward by sessile, epibenthic, suspension feeders. Upsection, a shift in the ratio of faunal groups indicates increasing replacement by mobile epibenthos. Autochthonous faunal elements decline near the top where allochthonous taxa become important. In the basal portion of the formation the faunal succession indicates relatively shallow neritic habitats with a moderate influx of suspended sediment, followed by a period of slightly deeper neritic conditions. Probably a shallow bathyal environment was established at the transition to the overlying siliciclastic Cabitza Formation. The bathymetric and ecofacies changes in the Campo Pisano Formation are interpreted as having been caused by a discontinuous rise in eustatic sea-level, probably accompanied by subsidence due to tensional tectonics. The depositional environment was that of a distal open-marine shelf or ramp without strong relief. This interpretation is supported by the lack of significant lateral changes in the fossil assemblages, and an upward deepening of facies. The applied micropaleoecological approach is proven a powerful tool in regional stratigraphy and in the reconstruction of sedimentary realms in the Mediterranean Cambrian, particularly when high-resolution biostratigraphic data and diagnostic sedimentary characteristics are sparse.

Online since February 14, 2006


Letter 1 [2006]: The Gargasian (Middle Aptian) of La Tuilière - St-Saturnin-lès-Apt (area of the Aptian historical stratotype, Vaucluse, SE France): geographic setting and outcrop correlation, by Michel MOULLADE, Guy TRONCHETTI, Christine BALME & Georges KOUYOUMONTZAKIS.-
Format [HTML] or [PDF 553 KB]
Reference: [CG2006_L01]
DOI: 10.4267/2042/4564
Lang.:  

 Abstract:  A stratonomic and micropaleontological analysis of the Aptian marls cropping out in the La Tuilière area near Saint-Saturnin-lès-Apt (Vaucluse, SE France), enabled us to reconstitute a continuous succession almost 120 m thick, that includes the upper terms of the Lower Aptian (Bedoulian) and the lower part of the Middle Aptian (Gargasian). These levels had never before been observed with such continuity in the Gargas region, the Aptian historical stratotype.

Online since January 30, 2006


up2  

2005 (vol. 5) 

Memoir 2 [2005]: Pre-Cambrian to Palaeozoic Palaeopalynology and Palaeobotany, edited by Philippe STEEMANS & Emmanuelle JAVAUX.-
Format [HTML] or [PDF 142 KB]
Reference: [CG2005_M02]
DOI:10.4267/2042/4353
Lang.: 

 Abstract:   A set of 14 abstracts and short papers (extended abstracts) of presentations given at a meeting organized by the NFSR Working Group, "Micropaléontologie végétale et Palynologie (MVP)", held on May 11, 2005 at the University of Liège, Belgium. These contributions are available only in English.

1- Breuer P., Al-Ghazi A., Filatoff J., Higgs K.T., Steemans P. & Wellman C.H.- Stratigraphic palynology of Devonian boreholes from northern Saudi Arabia.
DOI:10.4267/2042/4355
Lang.: 


2- François L., Grard A. & Goddéris Y.- Modelling atmospheric CO2 changes at geological time scales.
DOI:10.4267/2042/4356
Lang.: 


3- Gerrienne P., Meyer-Berthaud B. & Fairon-Demaret M.- The significance of Runcaria (Middle Devonian, Belgium) in the evolution of seed plants.
DOI:10.4267/2042/4357
Lang.: 


4- Golubkova E. & Raevskaya E.- Main changes in microfossil communities during the Upper Proterozoic of Russia.
DOI:10.4267/2042/4358
Lang.: 


5- Javaux E.J. & Marshall C.P.- Tracking the record of early life.
DOI:10.4267/2042/4359
Lang.: 


6- Prestianni C.- Early diversification of seeds and seed-like structures.
DOI:10.4267/2042/4360
Lang.: 


7- Raevskaya E.- Diversity and distribution of Cambrian acritarchs from the Siberian and East-European platforms - a generalized scheme.
DOI:10.4267/2042/4361
Lang.: 


8- Ribecai C., Bagnoli G., Mazzarini F. & Musumeci G.- Paleontological evidence for Late Cambrian in the Arburese area, SW Sardinia.
DOI:10.4267/2042/4362
Lang.: 


9- Rubinstein C.V.- Ordovician to Lower Silurian palynomorphs from the Sierras subandinas (Subandean ranges), northwestern Argentina: a preliminary report.
DOI:10.4267/2042/4363
Lang.: 


10- Streel M. & Hartkopf-Fröder C.- Late Famennian correlation by miospores between the Refrath 1 borehole (Bergisch Gladbach-Paffrath Syncline, Germany) and the reference section of Chanxhe (Dinant Syncline, Belgium).
DOI:10.4267/2042/4364
Lang.: 


11- Vanguestaine M. & Brück P.M.- A Middle Cambrian age for the Ediacara fauna from the Booley Bay Formation, County Wexford, Ireland: new acritarch data and its implications.
DOI:10.4267/2042/4365
Lang.: 


12- Vanmeirhaeghe J., Yans J., Préat A., Grassineau N. & Verniers J.- New evidence for the Hirnantian (Upper Ordovician) in Belgium? An integrated isotopical, biostratigraphical and sedimentological approach.
DOI:10.4267/2042/4366
Lang.: 


13- Vecoli M., Lehnert O. & Servais T.- The role of marine microphytoplankton in the Ordovician biodiversification event.
DOI:10.4267/2042/4367
Lang.: 


14- Wauthoz B.- Correlation and biostratigraphy of the Kortrijk (Sint-Antonius) and Kortrijk (Lust) boreholes (early Silurian, Belgium).
DOI:10.4267/2042/4368
Lang.: 

Online since December 31, 2005


Article 4 [2005]: Early Aptian δ13C and manganese anomalies from the historical Cassis-La Bédoule stratotype sections (S.E. France): relationship with a methane hydrate dissociation event and stratigraphic implications, by Maurice RENARD, Marc de RAFÉLIS, Laurent EMMANUEL, Michel MOULLADE, Jean-Pierre MASSE, Wolfgang KUHNT, Jim A. BERGEN & Guy TRONCHETTI.-
Format [HTML] or [PDF 866 KB]
Reference: [CG2005_A04]
DOI:10.4267/2042/3229
Lang.: 

 Abstract:  Comparison of oxygen and carbon isotope and manganese evolution curves in bulk carbonate from the historical Bedoulian stratotype (Cassis-La Bédoule area, Provence, France) reveals an important geochemical event (negative δ13C and high Mn content) located within the D. deshayesi ammonite Zone and at the base of the R. hambrowi ammonite Subzone. This worldwide event, which can be observed in environments ranging from the fluvial to the pelagic realm (Selli/Goguel level), seems to be related to methane hydrate destabilization. Scenarios for manganese, carbon and oxygen evolutions are proposed for early Bedoulian oxic conditions and for dysoxic/anoxic conditions related to methane hydrate destabilization at the early/late Bedoulian transition. The impacts of this global event on the biosphere (nannoconid crisis) and its stratigraphic implications are considered. Comparison of geochemical and biostratigraphical data from the Cassis-La Bédoule stratotype with that of the Cismon-Apticore reference borehole shows that the La Bedoule sequence records geochemical evolution during the Goguel/Selli Event in more detail than that of any other previously published section.

Online since November 25, 2005


Article 3 [2005]: The distribution of worm borings in brachiopod shells from the Caradoc Oil Shale of Estonia, by Olev VINN.-
Format [HTML] or [PDF 2,396 KB]
Reference: [CG2005_A03]
DOI:10.4267/2042/2454
Lang.: 

 Abstract:   Abundant worm borings were found in some brachiopod shells (Clitambonites, Estlandia, Nicolella) from the Ordovician (Caradoc) oil shale in North Estonia. 9 of 21 brachiopod genera (43 %) have been bored. Excluding the size and thickness of valves, no common morphological feature discriminates the brachiopods with borings from those without them. The Trypanites are host-specific, and the frequency of bored valves varies from 6.5 % in Bekkerina to 51 % in Estlandia. The worm larvae preferred hosts with thick lamellose shells, such as those of the clitambonitids, especially Clitambonites schmidti. The boring organisms were size-selective; they preferred large adult specimens. The majority of the borings are oriented, and living hosts were preferred to dead shells. Some clitambonitidine brachiopods, like C. schmidti tolerated a large number of the borer's shafts in their valves. Few bored valves have the blister-like shell-repair structures in their interior.

Online since October 6, 2005


Letter 1 [2005]: The "sauropod" from the Albian of Mesnil-Saint-Père (Aube, France): a pliosaur, not a dinosaur, by Eric BUFFETAUT, Claude COLLETÉ, Bruno DUBUS & Jean-Louis PETIT.-
Format [HTML] or [PDF 528 KB]
Reference: [CG2005_L01]
DOI:10.4267/2042/2380
Lang.:  

 Abstract:  A vertebra from the Albian of Mesnil-Saint-Père (Aube, eastern Paris Basin), previously identified as the first caudal of a sauropod dinosaur, is shown to be a dorsal vertebra of a large pliosaur. The specimen resembles vertebrae from the Albian of England and eastern France that have been referred to the pliosaur Polyptychodon, a taxon in need of revision.

A paper-printed version was published as : "Association Géologique Auboise, Bulletin Annuel, Sainte-Savine, n° 26 (décembre 2005), p. 3-8.

Online since September 13, 2005


Memoir 1 [2005]: Discoaster zonation of the Miocene of the Kutei Basin, East Kalimantan, Indonesia (Mahakam Delta Offshore), by Bernard LAMBERT & Cécile LAPORTE-GALAA.-
Format [HTML] or [PDF 9,897 KB]
Reference: [CG2005_M01]
DOI:10.4267/2042/1461
Lang.: 

 Abstract:  Thirteen time-stratigraphic associations of the nannofossil Discoaster have been defined and used in the Miocene Kutei Basin of eastern Borneo to establish a regional stratigraphic framework. The methodology used is discussed and the fossils employed are figured and annotated. Their aid in resolving the timing, stages and details of delta construction is presented graphically.

Online since May 26, 2005


Article 2 [2005]: The Gargasian (Middle Aptian) strata from Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): planktonic and benthic foraminiferal assemblages and biostratigraphy, by Michel MOULLADE, Guy TRONCHETTI & Jean-Pierre BELLIER.-
Format [HTML] or [PDF 3,038 KB]
Reference: [CG2005_A02]
DOI:10.4267/2042/1460
Lang.:  

 Abstract:  This paper presents a thorough analysis of foraminiferal assemblages ranging in age from the Bedoulian-Gargasian transition to the middle Gargasian in the Cassis-La Bédoule area (SE France), the historical stratotype of the Lower Aptian substage. This region is particularly suitable for detailed studies of Aptian foraminifera owing to rapid and continuous sediment depositional rates and well-diversified microfaunas. The ranges of benthic forms appear to be fairly stable but some species (Praedorothia praeoxycona, Lenticulina cf. nodosa, Astacolus crepidularis, Globorotalites bartensteini) become extinct at the end of the Bedoulian and thus can be used to separate this substage from the Gargasian. The stratotypic area also offers an opportunity to follow the evolution of planktonic forms step by step at a crucial period of their history, when modalities of speciation and phylogenetic relationships appear to be particularly complex. The important morphologic variability of Aptian planktonic foraminifera does not help finding stable stratigraphic markers; nevertheless, we are able to propose a biozonation comprising five zones (Cabri, Luterbacheri, Ferreolensis, Barri, Algerianus) for the interval under consideration, usually subdivided into three zones. Our study of foraminiferal assemblages and species took into account the range of variability among populations and not just the characteristics of a single specimen, such as the holotype. As a result this paper provides new taxonomic precisions on certain planktonic species hitherto controversial or possibly of doubtful validity.

Online since April 5, 2005


Article 1 [2005]: The modern environments of Molluscs in southern Mesopotamia, Iraq: A guide to paleogeographical reconstructions of Quaternary fluvial, palustrine and marine deposits, by Jean-Claude PLAZIAT & Woujdan R. YOUNIS.-
Format [HTML] or [High Resolution PDF 5,450 KB] or [Low Resolution PDF 3,130 KB]
Reference: [CG2005_A01]
DOI:10.4267/2042/1453
Lang.: 

 Abstract:   The Quaternary, mainly freshwater sediments of the Lower Mesopotamian plain include a thin transgressive marine unit which extends inland some 250 km from the present coastline, the Hammar Formation. The identity and respective areal extent of continental and transgressive units are based mainly on their molluscan faunas. Those faunas reflect the several environments of the Middle Eastern biogeographic province: fluviatile, lacustrine, estuarine and lagoonal. The ecological requirements of the more common subfossil and living species of the malacofauna were studied during a month of field reconnaissance.
The freshwater portion comprises only four bivalve species (Corbicula, Unio, Anodonta and Pseudodontopsis). The principal gastropods include Theodoxus (Neritaea), Melanopsis, Melanoides, Bellamya, Gyraulus, Lymnaea (Radix) spp. Corbicula characterizes both fluviatile channels and lacustrine environments; Melanopsis, Melanoides, Theodoxus and the Unionaceae prefer shallow, sparsely vegetated, freshwater lakes. The greatest diversity was seen in the slowly flowing water of the channels draining the marshes; small Planorbids are rarely abundant whereas viviparid and lymnaeids may accumulate near the margins of marshes due to floatation during floods.
The brackish water faunas are characterized by Neritina (Dostia), the potamid Cerithidea (Cerithideopsilla), and Stenothyra. The new combination Theora mesopotamica (Annandale, 1918) is introduced here as the exact equivalent of Abra cadabra Eames et Wilkins, 1957. The abundance of these species is indicative of a restricted, low energy marine environment, confirmed by great numbers of the foraminiferan Ammonia gr. beccarii and the ostracod Cyprideis gr. torosa.
Reworked Hammar Fm marine fossils, first recorded by the Annandale (1918) collection from a lacustrine deposit near Nassiriyah, have been observed in river, marsh and lake sediments too, usually in association with scarce foraminifera. The limited occurrence of these macrofossils (abundant in their life environment) indicates reworking.

Online since January 13, 2005


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2004 (vol. 4) 

Article 2 [2004]: Stage boundaries, global stratigraphy, and the time scale: towards a simplification, by Gilles Serge ODIN, Silvia GARDIN, Francis ROBASZYNSKI & Jacques THIERRY.-
Format [HTML] or [PDF 750 KB]
Reference: [CG2004_A02]
DOI:10.4267/2042/290
Lang.: 

 Abstract:  This paper examines four facets of stratigraphic terminology and usage considered faulty and proposes corrective measures. The four perfectible areas are:
(1) The system of dual nomenclature requiring discrete terminologies for the superpositional and temporal aspects of rock units.
(2) The premise that a GSSP establishes the base of a stage as being coincident with the top of the preceding stage rather than simply defining it as the boundary between stages.
(3) The rejection of supplementary (auxiliary) sections that would broaden the knowledge of a GSSP and enlarge the area in which it is easily usable.
(4) The current dual system of nomenclature for Precambrian and Phanerozoic strata is accepted, but a third system is proposed for strata formed in the last 3 to 5 Ma.
In addition, the paper advocates a broader use of a limited number of conventions but warns against their proliferation; units shortened thereby would be more difficult to recognize. It points out the clear distinction between these conventions - a matter of administration and general compliance - and knowledge - a domain where free expression of opinion is indispensable -.

 Errata:  Some errors were encontoured in the above Article. Corrections are listed below. Editors and authors apologize for any inconvenience.

1- Abstract: The sentence "The current dual system of nomenclature for Precambrian and Phanerozoic strata is accepted" should read: "The current different system of subdivision for Precambrian and Phanerozoic strata is accepted". 

2- Figure 2: The words "Lower" and "Upper" in the lower line should obviously read "Early" and "Late" respectively. 

3- Figure 3: The words "Main Hierarchy", lower line of the left column, should read "Sub Hierarchy".

Online since December 3, 2004


Letter 5 [2004]: On a Deinotherium (Proboscidea) finding in the Neogene of Crete, by Athanassios ATHANASSIOU.-
Format [HTML] or [PDF 353 KB]
Reference: [CG2004_L05]
DOI:10.4267/2042/311
Lang.: 

 Abstract:  This paper reports the discovery of an incomplete proboscidean mandible near the village of Maroniá in eastern Crete. The fragment described here includes the first molar (m1) of a deinothere, that because of its large size is identified as Deinotherium giganteum. The specimen was found in shallow-water marine sediments. The presence of Deinotherium on the island, together with other Miocene vertebrate faunas, suggests that during that epoch Crete was connected to the mainland by a wide land bridge.

Online since November 25, 2004


Letter 4 [2004]: New data on the lophophore anatomy of Early Cambrian linguloids from the Chengjiang Lagerstätte, Southwest China, by Zhi-Fei ZHANG, De-Gan SHU, Jian HAN & Jian-Ni LIU.-
Format [HTML] or [PDF 530 KB]
Reference: [CG2004_L04]
DOI:10.4267/2042/310
Lang.: 

 Abstract:  A succession of developmental types in the lophophores of lingulid brachiopods is reported from the Early Cambrian Chengjiang deposits of South China. These types range from trocholophe, schizolophe to simple coiled spirolophe. Of Atdabanian age, this succession of forms is mirrored in the ontogeny of the lophophore of Recent linguloids, thus demonstrating a close similarity in the development of the lophophores of Cambrian and Recent forms. We illustrate also more than 10 extraordinary specimens with aberrant dispositions of the lophophoral arms that extend to unusual lengths either inside or outside the shell.

Online since October 28, 2004


Letter 3 [2004]: Laboratory cultures of calcifying biomicrospheres generate ooids - A contribution to the origin of oolites, by Ulrike BREHM, Katarzyna A. PALINSKA & Wolfgang E. KRUMBEIN.-
Format [HTML] or [PDF 4,929 KB]
Reference: [CG2004_L03]
DOI:10.4267/2042/309
Lang.: 

 Abstract:  The in vitro production of ooid-like structures as possible precursors of oolites has been observed in laboratory cultures of spherical microbial communities isolated from the Wadden Sea (North Sea). The microbial spherulites consist of aggregated benthic diatoms (Navicula perminuta) enveloped by layers of filamentous cyanobacteria of the genus Phormidium and a halo-like biofilm of heterotrophic bacteria. The development of the structures takes several months and these configurations appear to be stable, before they calcify. The precipitation starts on the surface of the spheres as clouds of small scattered crystals, which later increase in size and aggregate to form hollow spheres around the microbial assemblage. Here we report for the first time carbonate precipitation in defined spherical microbial communities.

 Corrigendum:  The authors take this opportunity to rectify a failure to credit Professor-Doctor Heribert CYPIONKA of the Carl von Ossietzky University in Oldenburg, Germany, as the author of the videofile "Cyanobacterial movement inside a biomicrosphere". The videofile in question is one of a number of interesting documents put online by Professor CYPIONKA at: http://www.icbm.de/pmbio/mikrobiologischer-garten/eng/index.php3

Online since June 20, 2004


Article 1 [2004]: The Mediterranean deep-sea fauna: historical evolution, bathymetric variations and geographical changes, by Christian C. EMIG & Patrick GEISTDOERFER.-
Format [HTML] or [PDF 539 KB]
Reference: [CG2004_A01]
DOI:10.4267/2042/3230
Lang.:  

 Abstract:   The deep-water fauna of the Mediterranean is characterized by an absence of distinctive characteristics and by a relative impoverishment. Both are a result of events after the Messinian salinity crisis (Late Miocene). The three main classes of phenomena involved in producing or recording these effects are analysed and discussed:
- Historical: Sequential faunal changes during the Pliocene and thereafter in particular those during the Quaternary glaciations and still in progress.
- Bathymetric: Changes in the vertical aspects of the Bathyal and Abyssal zones that took place under peculiar conditions, i.e. homothermy, a relative oligotrophy, the barrier of the Gibraltar sill, and water mass movement. The deeper the habitat of a species in the Mediterranean, the more extensive is its distribution elsewhere.
- Geographical: There are strong affinities and relationships between Mediterranean and Atlantic faunas. Endemic species remain a biogeographical problem. Species always become smaller in size eastward where they occupy a progressively deeper habitat.
Thus, the existing deep Mediterranean Sea appears to be younger than any other deep-sea constituent of the World Ocean.

Online since April 12, 2004


Letter 2 [2004]: The Gargasian (Middle Aptian) of Cassis-La Bédoule (Lower Aptian historical stratotype, SE France): geographic location and lithostratigraphic correlations, by Michel MOULLADE, Guy TRONCHETTI, Wolfgang KUHNT, Maurice RENARD & Jean-Pierre BELLIER.- (...)
Format [HTML] or [PDF 911 KB]
Reference: [CG2004_L02]
DOI:10.4267/2042/307
Lang.:  

Online since March 21, 2004


Letter 1 [2004]: The Gargasian (Middle Aptian) substage in the Aptian historical stratotypes (SE France): General introduction, by Michel MOULLADE & Guy TRONCHETTI.- (...)
Format [HTML] or [PDF 135 KB]
Reference: [CG2004_L01]
DOI:10.4267/2042/306
Lang. :  

Online since March 15, 2004


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2003 (vol. 3) 

Letter 3 [2003]: Note on magnesite formation (Studies on irreversible geochemical reactions Nº 9), by John C. DEELMAN.-
Format [HTML] or [PDF 250 KB]
Reference: [CG2003_L03]
DOI:10.4267/2042/305
Lang.: 

 Abstract:  In recent laboratory experiments magnesite (MgC03) has been synthesized at a temperature of 313ºK (= 40ºC). The experiments have demonstrated that irreversible reactions are involved in the low-temperature formation of magnesite. Fundamental to such irreversible reactions is a requirement for fluctuations, i.e., alternations between precipitation and dissolution. But unequivocal evidence for the necessity for fluctuations in order to produce such irreversible geochemical reactions can be demonstrated only by static control experiments. The present note describes several static control experiments on the low-temperature synthesis of magnesite. The first experiment consisted of adding the total amount of ammonia (used in the original experiment in 14 different titration steps) in a single action: only magnesium hydroxide carbonate formed, not magnesite. In the second experiment the possible reaction between magnesium chloride, ammonia and carbon dioxide in solution was studied at 318ºK (= 45ºC): magnesium hydroxide formed, not magnesite. The third static control experiment involved the reaction between magnesium chloride and ammonium carbamate; this time nesquehonite formed, not magnesite. The implications of these static control experiments in relation to the low-temperature formation of magnesite and dolomite in the sedimentary environment are discussed.

Online since December 4, 2003


Article 7 [2003]: Pristiograptus (Graptoloidea) from the perneri-lundgreni biozones (Silurian) of Lithuania, by Sigitas Radzevičius.-
Format [HTML] or [PDF 1,749 KB]
Reference : [CG2003_A07]

DOI:10.4267/2042/300

Lang.: 

 Abstract:   Two new forms of Pristiograptus dubius, here designated as varieties "A" and "B", are described and figured. Both were found in core samples representing the perneri through lundgreni biozones of the Wenlock epoch. The cores are from boreholes Šiupyliai-69, Parovėja-9, Likėnai-396, Paežeriai-222 and Sutkai-87 in central and northern Lithuania. The associated graptolites Cyrtograptus perneri Bouček, C. radians Törnquist, C. lundgreni Tullberg, Monograptus flemingii flemingii (Salter), M. testis testis (Barrande), Monoclimacis flumendosae (Gortani) and Pristiograptus pseudodubius (Bouček) (= P. parvus) are all indicative of the perneri, radians and lundgreni biozones of the Wenlock. Two species of Pristiograptus occur in this time-stratigraphic interval: P. dubius and P. lodenicensis. In P. dubius the degree and manner of extension of the thecal apertural lip (thecal hood) onto the succeeding theca distinguish it from otherwise very similar taxa. The thecal morphology of P. lodenicensis differs from that of a typical Pristiograptus in that the apertural lip has a central depression and is rounded into small lobes laterally.

Online since November 22, 2003


Reply to Article 6 [2003]: Reply to L.E. Popov and L.E. Holmer (CG2003_A06): Obolid taxonomy, by Christian C. EMIG.
Format [HTML] or [PDF 516 KB]
Reference : [CG2003_A06_Reply]

DOI:10.4267/2042/299

Lang.: 

Online since October 4, 2003


Article 6 [2003]: Understanding linguloid brachiopods: Obolus and Ungula as examples, by Leonid E. POPOV & Lars E. HOLMER.-
Format [HTML] or [PDF 2,806 KB]
Reference: [CG2003_A06]
DOI:10.4267/2042/298
Lang.: 

 Abstract:  EMIG (2002) re-examined the taxonomy of the genus Obolus EICHWALD from the Middle Cambrian - earliest Ordovician of the East Baltic region as part of a proposal for a wholesale revision of the principles of linguloid systematics. He contended that previous taxonomic studies on Obolus and related forms were carried out erroneously using characters that have no taxonomic value. EMIG's proposed revision is based mainly on the limited morphological diversity between fossil and Recent taxa within a single linguloid Family, the Lingulidae. However, the present study demonstrates the taxonomic validity of the diagnostic characters used for classification within the mostly extinct families of the Superfamily Linguloidea, for they exhibit far more variation in morphology. This study also shows that EMIG has provided no satisfactory basis for his radical changes and revisions to the existing widely accepted taxonomy of the Cambrian to earliest Ordovician Obolidae of the East Baltic. Obolus EICHWALD and Ungula PANDER are shown to constitute distinctive and discrete genera comprising the species Obolus apollinis EICHWALD, O. ruchini KHAZANOVITCH et POPOV, O. transversus (PANDER), Ungula ingrica (EICHWALD), U. inornata (MICKWITZ), and U. convexa PANDER.

Online since September 12, 2003


Article 5 [2003]: New insight on the stratigraphy of the "Upper Thamama" in offshore Abu Dhabi (U.A.E.), by Bruno GRANIER, Ahmed Saqer AL SUWAIDI, Robert BUSNARDO, Sabah Karim AZIZ & Rolf SCHROEDER.-
Format [HTML] or [PDF 7,938 KB]
Reference: [CG2003_A05]
DOI:10.4267/2042/297
Lang.: 

 Abstract:   An integrated case study of field "A" in offshore Abu Dhabi found that the stratigraphic framework for the uppermost part of the so-called "Thamama Group" required revision. Detailed sedimentological work permitted a subdivision of the succession into lithostratigraphic units (more accurately "allostratigraphic units") and the fossil content permitted their allocation to standard age-related units ranging from Late Barremian through Middle Aptian times. Additional work focused on the so-called "Shu'aiba Formation" and resulted in a new and comprehensive interpretation on a regional scale which differs from published interpretations based on onshore studies in Abu Dhabi, Qatar, and Oman.

Online since July 31, 2003


Article 4 [2003]: A new approach in rock-typing, documented by a case study of layer-cake reservoirs in field "A", offshore Abu Dhabi (U.A.E.), by Bruno GRANIER.-
Format [HTML] or [PDF 436 KB]
Reference: [CG2003_A04]
DOI:10.4267/2042/296
Lang.: 

 Abstract:  In carbonate reservoirs, the relationship between porosity Ø, a measure of the combined volumes of several kinds of pore space (e.g. interparticle and separate-vug), and permeability K are neither linear nor logarithmic, hence only weakly correlatable. Approaches to an estimation of permeability that employ both petrographical and petrophysical parameters, the so-called rock-typing techniques, have proven to be the most nearly precise. However in many studies simple K/Ø cross-plots are used for each rock-type to provide trendlines from which K values are derived as a function of Ø values; this is common practice even though the coefficient of correlation r2 departs significantly from 1.
This paper describes and provides examples of an improved technique of rock-type classification in which each rock-type is characterized by a discrete and unique Gaussian distribution of log K. It facilitates upscaling for it suggests the use of a single geometric mean value for permeability and a corresponding standard deviation (variance, or coefficient of variation) for each rock-type.
This new technique can be used in uncored wells by extrapolating these determinations into wireline logs as documented below in a case study of layer-cake reservoirs in a field of the Abu Dhabi offshore (U.A.E.).

Online since July 12, 2003


Letter 2 [2003]: Lower sea levels in the Middle Cenomanian, by Jake M. HANCOCK.-
Format [HTML] or [PDF 280 KB]
Reference: [CG2003_L02]
DOI:10.4267/2042/304
Lang.: 

 Abstract:  It has been known since the 1970's that the relatively high sea levels during the Cenomanian in southern England and northern France were interrupted by a strong fall in sea level early in the Middle Cenomanian. This was a eustatic trough whose effects can be found not only in north-west Europe, but also from western Kazakhstan in central Asia to Texas, Colorado and South Dakota in the U.S.A.

Online since July 3, 2003


Letter 1 [2003]: Proof that Lingula (Brachiopoda) is not a living-fossil, and emended diagnoses of the Family Lingulidae, by Christian C. EMIG.-
Format [HTML] or [PDF 1,204 KB]
Reference: [CG2003_L01]
DOI:10.4267/2042/303
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 Abstract:  Lingula is often considered a "living-fossil" based on its supposed lengthy morphological conservatism owing to its absence of evolution, and its remarkable survival for more than 550 M.Y. This conclusion is based on the typical apparently unchanged "linguliform" shape of the shell. However the taxa of the family Lingulidae show morphological evolutionary changes despite the fact that the group appears panchronic among the Recent Brachiopoda. Consequently, traditional opinion that Lingula is a "living-fossil" should be rejected. Diagnoses of the Family Lingulidae and of its three genera are herewith emended.

Online since May 1, 2003


Article 3 [2003]: The Cretaceous of the Elbe valley in Saxony (Germany) - a review, by Karl-Armin TRÖGER.-
Format [HTML] or [PDF 377 KB]
Reference: [CG2003_A03]
DOI:10.4267/2042/295
Lang.: 

 Abstract:  In Central Europe one of the most important interchanges between the North Temperate Realm and the Tethyan Realm took place during the Cenomanian along the course of the Elbe Valley Geosuture that separates the Erzgebirge block (part of the Mid European Island during the Cretaceous) from the Lusatian block (West Sudetic Island). Strata of the Lower Cretaceous and the basal portion of Lower Cenomanian are absent in the Elbe Valley Geosuture but a marine transgression in a NW-SE direction occupied a portion of this tract during the late Early Cenomanian and a second incursion from SE to NW occurred during the Late Cenomanian. These transgressions are known to have occurred because of faunal migrations southwards from the North Temperate Realm and northwards from the Tethyan Realm across the Bohemian Basin. Sediments of the first transgression (Lower Cenomanian, dixoni zone) are restricted to the northwestern part of the Elbe Valley Geosuture in the Meissen area for at that time the fluvial Niederschöna Formation occupied the southern part of the Elbe Valley Geosuture and the adjacent Erzgebirge block. Most of the rivers in this system ran eastward but drained toward northern Bohemia. This fluvial environment predominated in the southern part of the Elbe Valley Geosuture and on the adjacent Erzgebirge block.
But the uppermost levels of the fluviatile Niederschöna strata are influenced by marine ingressions. The main transgression from the North Temperate Realm toward the Tethyan Realm took place in the basal Upper Cenomanian (naviculare zone) along the Elbe Valley Geosuture. A small regression followed (plenus event, geslinianum zone): Indications of this regression are visible on the flanks of small islands in the Elbe Valley Geosuture. Four marine sequences are recognized in strata dated Late Cenomanian - earliest Turonian.
These sequences are important for the comparison of Upper Cretaceous formations in Saxony with those of the Upper Cretaceous in northern Bohemia and in the peripheral areas of the NW German-Polish Basin, in the Münsterland, Subhercynian, Eichsfeld regions and in the Anglo-Paris Basin. These sequences are described and their influence on the changes in the paleogeography in the Elbe Valley Geosuture is discussed. Slight variations in sea level as a consequence of local tectonic movements in the Elbe Valley Geosuture cannot be precluded.

Online since April 26, 2003


Article 2 [2003]: Micropaleontological investigations in the modern Mahakam delta, East Kalimantan (Indonesia), by Bernard LAMBERT.-
Format [HTML] or [PDF 4,845 KB]
Reference: [CG2003_A02]
DOI:10.4267/2042/294
Lang.: 

 Abstract:   The Mahakam delta is a mixed, fluvial and wave dominated delta located in the eastern part of the island of Borneo (the East Kalimantan province of Indonesia). The distribution of benthic fauna in this delta system is influenced by the combined or antagonistic action of three main parameters: fluvial input of fresh water and sediment, tide, and a strong regional north to south drift current. A model of the present-day faunal distribution has been established taking into account the perturbations induced by the tide and by the regional drift current. This model has been extrapolated into the recent past through the study of shallow cores that permit the reconstruction of late Holocene deltaic regression patterns.

Online since March 8, 2003


Article 1 [2003]: The Cenomanian: stage of hindlimbed snakes, by Jean-Claude RAGE & François ESCUILLIÉ.-
Format [HTML] or [PDF 1,578 KB]
Reference: [CG2003_A01]
DOI:10.4267/2042/293
Lang.: 

 Abstract:   Three "snakes with legs" are known: Pachyrhachis problematicus, Haasiophis terrasanctus and Eupodophis descouensi. They have short posterior limbs but lack an anterior girdle and forelimbs. Moreover, Pachyophis woodwardi, Mesophis nopcsai and Simoliophis ssp. appear to be closely related to the hindlimbed taxa; consequently, although the presence of posterior limbs has not been demonstrated for these genera, it is presumed that they too were hindlimbed. All these snakes have been recovered only from the Cenomanian. Moreover, these six genera come from a restricted area (western Europe and northwesternmost Africa to the Middle East). This limited geographic range suggests that snakes might have originated in the "Mediterranean" part of the Tethys, but the restricted stratigraphical range remains unexplained.

Online since February 17, 2003


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2002 (vol. 2) 

Article 1 [2002]: Tools for linguloid taxonomy: the genus Obolus (Brachiopoda) as an example, by Christian C. EMIG.-
Format [HTML] or [PDF 637 KB]
Reference: [CG2002_A01]
DOI:10.4267/2042/301
Lang.: 

 Abstract:   This study points out some basic problems of linguloid systematics and proposes solutions for them. A taxonomic examination of the unique species of the genus Obolus found in the Upper Cambrian of Estonia and Russia, O. apollinis (= O. ruchini, O. transversus, O. rebrovi and Ungula convexa) is used as an example of a methodology employing all of the characters valid for distinguishing species of both extant and fossil Lingulidae. These characters are: - umbonal region; - body musculature; - septa or ridges; - main mantle canals - as established and figured by EMIG (1982, 1983) and BIERNAT and EMIG (1993). All of them have been determined to be taxonomically stable and have been studied and compared to take into account intraspecific variability; they should be used to describe or to redescribe any taxon of the superfamily Linguloidea. Characters of the shell and valves, such as shape, size, and dimensional ratios have no taxonomic value.

Online since November 27, 2002


Memoir 1 [2002]: Diatom based transfer function for estimating the chemical composition of fossil water. Calibration based on salt lakes of the Lipez area in the southwestern Bolivian Altiplano, by Simone SERVANT-VILDARY, François RISACHER & Maurice ROUX.-
Format [HTML]
Reference: [CG2002_M01]
DOI:10.4267/2042/4566
Lang.: 

 Abstract:   Diatom assemblages and water chemistry were studied in 13 shallow salt lakes in the southern part of the Bolivian Altiplano. At each locality bottom sediment and water samples were collected simultaneously. Relationships between the composition of the diatom assemblages and variations in water chemistry were collated in order to permit the estimation of ancient water chemistries based on changes in the make up of fossil diatom associations in older sediments. Weighted Averages treated by Partial Least Squares regression (WA and WA-PLS methods) allowed an estimation of optima and the relative tolerances of 61 species to variations in salinity and to the relative quantities of the 15 chemical elements studied, among them boron and lithium.

Online since October 14, 2002

2nd edition: On January 30, 2006 we edited the pdf file of the first memoir either published in Carnets.
Format [PDF 885 KB]
Reference: [CG2002_M01]
Lang.: 

Online since January 30, 2006


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2001 (vol. 1) 

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