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2015 (vol. 15)  

Lower Valanginian ammonite biostratigraphy in the Subbetic Domain (Betic Cordillera, southeastern Spain)

 | 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

 | 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

 | 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


2014 (vol. 14)  

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

    | 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

 | 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)

 | 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

 | 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

 | 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)

 | 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

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

 | 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

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 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

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 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

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 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

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 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

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