Search results for "STRATIGRAPHY"
showing 10 items of 904 documents
The Upper Sinemurian ammonite succession in the Sierra Madre Oriental (Mexico).
2009
International audience; In the Sierra Madre Oriental (Mexico), the biostratigraphic subdivision of the Upper Sinemurian can be refined. It has been possible to differentiate 11 horizons from the upper Obtusum Zone to the top of the Raricostatum Zone which are correlated with the NW European standard zonation. The index species of each horizon is figured.
Reconstitutions paléoenvironnementales et enregistrement paléoclimatique fini-carbonifère à permien du bassin d’Autun (Nord-Est du Massif Central)
2018
International audience; Les bassins sédimentaires tardi-orogéniques fini-carbonifères à permiens du Nord-Est du Massif Central (bassins d’Autun, de l’Aumance, de Decize-La Machine et de Blanzy-Le Creusot) ont été principalement étudiés pour leur potentiel en ressources carbonées jusque dans les années 1980. Le regain d’intérêt qu’ils suscitent aujourd’hui s’appuie sur des aspects plus fondamentaux afin de mieux comprendre la période charnière qu’est la fin du Paléozoïque. Les séries sédimentaires préservées dans ces bassins continentaux enregistrent en effet le démantèlement des reliefs hercyniens ainsi que l’évolution climatique (transition icehouse-greenhouse) se produisant entre la fin d…
Revision of asterolepidoid antiarch remains from the Ogre Formation (Upper Devonian) of Latvia
2020
The Frasnian (Upper Devonian) antiarch Walterilepis speciosa was first described in 1933 (as Taeniolepis) on the basis of a single specimen. The newly collected material has allowed the head to be described in a more detail, especially the nuchal and paranuchal plates. Other newly described elements include bones of the pectoral appendages and trunk armour, demonstrating a rather high and short trunk armour. The shape and proportions of the head and trunk armour suggest the attribution of Walterilepis to the family Pterichthyodidae; it is most probably closely related to Lepadolepis from the Late Frasnian of Germany. Whilst W. speciosa is endemic to the Latvian part of the Baltic Devonian B…
Synthesis of recent stratigraphic data on bathonian to oxfordian deposits of the eastern Paris basin
2007
International audience
Early Paleocene Paleoceanography and Export Productivity in the Chicxulub Crater
2021
The Chicxulub impact caused a crash in productivity in the world''s oceans which contributed to the extinction of ~75% of marine species. In the immediate aftermath of the extinction, export productivity was locally highly variable, with some sites, including the Chicxulub crater, recording elevated export production. The long-term transition back to more stable export productivity regimes has been poorly documented. Here, we present elemental abundances, foraminifer and calcareous nannoplankton assemblage counts, total organic carbon, and bulk carbonate carbon isotope data from the Chicxulub crater to reconstruct changes in export productivity during the first 3 Myr of the Paleocene. We sh…
Presence of Naraoia Walcott, 1912 (Nektaspida, Arthropoda) in the middle Cambrian of Europe (Murero, NE Spain).
2018
The genus Naraoia Walcott, 1912, a Burgess Shale-type fossil known from the lower and middle Cambrian of British Columbia (Canada), Idaho and Utah (USA), as well as from Yunnan and Guizhou provinces (China), is now reported from the middle Cambrian of Murero (Zaragoza, Spain), which is the first record in the Acadobaltic province. The only fragmented specimen found is determined as Naraoia sp., its age being Pardailhania multispinosa Zone (Drumian Stage). This new datum reinforces the hypothesis of the existence of a cosmopolitan faunal substrate in early Cambrian times, which is to some extent refl ected in the mid Cambrian by faunal groups of low evolutionary potential as the family Narao…
Cenomanian rudist-dominated shelf-margin limestones from the Panormide carbonate platform (Sicily, Italy): facies analysis and sequence stratigraphy
2000
Sedimentological, paleontological and sequence analyses of Cenomanian limestones in Sicily reveal thc facies architecture and dynamics of a Mid Cretaceous rudistdominated platform margin from Western Tethys. The studied deposits outcrop near Palermo, as part of a large structural unit of the Sicilian Maghrebids. They belong to the Panormide carbonate platform, a Mesocenozoic paleogeographic domain of the African margin. The lateral continuity of the beds along three nearly parallel E-W outcrop sections allowed the recording of cm/dm thick lithological and faunal variations. Nine main lithofacies associations have been recognised along about 200 m of subvertical strata. Their vertical and la…
A database of Triassic conodonts from a comprehensive revisión of literature
2013
The revision of a comprehensive amount of bibliography has made possible the development of a database containing the stratigraphic ranges of the conodont species from the uppermost Permian and the Triassic, with a total of 336 species in 52 genera. This database is aimed at biostratigraphy and studies related to biological, evolutional and palaeodiversity dynamics. La revisión de una amplia cantidad de bibliografía ha hecho posible el desarrollo de una base de datos en la que figuran los rangos estratigráficos de las especies de conodontos presentes desde el Pérmico superior y el Triásico, con un total de 336 especies y 52 géneros. Esta base de datos está dirigida a la bioestratigrafía y a…
The Jaguar - Panthera onca gombaszoegensis (Kretzoi, 1938) (Carnivora: Felidae) in the late lower pleistocene of Akhalkalaki (south Georgia; Transcau…
2001
Abstract A lower hemimandibula of a pantherine cat of Akhalkalaki (south Georgia, Transcaucasia) is re-examinated. The fossil originates from lacustrine sediments of late Lower Pleistocene age (0.9 − 0.8 Ma B.P.) above the Jaramillo polarity subzone. A tooth-by-tooth analysis comparing the fossil with Lower and Middle Pleistocene lions, tigers and jaguars and Holocene southwest Asian lions assigns it to the Eurasian jaguar, Panthera onca gombaszoegensis. Palaeoenvironmental reconstruction indicates a dry, warm meadow-steppe influenced by montane condition, with permanent water bodies present. This is consistent with the strong open-water affinities of the modern jaguar. The morphological pr…
Coupures morphologiques et biochronologie chez les Kosmoceratinae de l'Est de la France (Callovien inférieur pp. à Callovien supérieur pp.)
1998
Abstract For the first time in eastern France, a detailed succession of the uppermost Lower Callovian to Lower Upper Callovian Kosmoceratinae is presented, according to the fossils collected in situ at Blye (Jura, France). It is compared with the abundant data from Champagne and Bourgogne. These ammonites may allow more accurate correlations between the subboreal and subtethysian biostratigraphical frameworks. They record numerous morphological changes, sometimes different from those generally accepted. They allow the precise recognition of the limits of the biostratigraphical units, and the definition of successive faunal units available in the lowermost Upper Callovian.