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2014 (vol. 14)  

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


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 Aďn 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


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