Search results for "Aptian"
showing 10 items of 23 documents
Multistratigraphic records of the Lower Cretaceous (Valanginian–Cenomanian) Puez key area in N. Italy
2016
Abstract We present a stratigraphic investigation of a Hauterivian to Cenomanian hemipelagic succession from Col Puez, in the Dolomites (Southern Alps, northern Italy). A composite section of seven segments was studied with bio-, magneto-, and chemostratigraphy, which enabled detailed and robust age calibration of the Puez succession. It also revealed the paleoceanographic history and helped identify the important global climatic events of that period. The age of the Lower Cretaceous Puez Formation in the Dolomites is refined as late Hauterivian to early Cenomanian. Ammonoids provide a detailed biostratigraphic subdivision that forms the basis for analyses of the faunal distribution and the…
Relations entre les variations climatiques, les perturbations du cycle du carbone et les crises de la production carbonatée : application au Crétacé …
2011
The Early Cretaceous is punctuated by carbon cycle perturbations, associated with organic matter burial episodes and carbonate production crises. These events coincide with short-term cooling (<1Ma), yet the mechanisms are still unclear, because of low resolution in sea surface temperature reconstructions. Recent climatic models suggest that carbonate-platform-collapse events may trigger a short-term ocean cooling episode (Donnadieu et al., accepted). In order to establish relations between climates and carbonate productions, we performed stratigraphic, palaeoecologic and geochemical analyses on Valanginian sediments from the La Charce-Vergol and the Ollioules sections (South-East France) a…
Montlivaltia multiformis Toula (Scleractinia) from the Aptian of the Prebetic Domain (SE Spain)
2021
Montlivaltia multiformis Taula (Scleractinia, Faviina, Montlivaltidae), formerly reported from the Carpatho Balkanic domain is described from Lower Aptian beds of the Prebetic Domain (SE Spain). Taxonomic attributes include the organisation of radial elements, septal trabeculae, carinae and endothecal elements while the external morphology of the coralla is fairly variable. The sedimentological context suggests a circalittoral environment also supported by palaecological features of the surrounding fauna. Owing to its stratigraphic position in the Carpatho-Balkanic region and in Spain, Montlivaltia multiformis appears as a potential marker for both shallow carbonate or outer shelf settings …
Paleoclimate and extensional tectonics of short-lived lacustrine environments. Lower Cretaceous of the Panormide Southern Tethyan carbonate platform …
2017
Abstract Subaerial erosion and continental sedimentation interbedded with shallow-water carbonates are unequivocal stratigraphic records to evaluate paleoenvironmental and paleoclimate evolution of emerged landmass. Stratigraphic analysis of the Cretaceous Monte Gallo section of the Mesozoic Panormide carbonate platform, in the northern side of the Palermo Mountains (NW Sicily) records a peculiar continental-derived clays that interrupted the shallow-water carbonate sedimentation. These clays rest, with lenticular geometries, above the tectonically-enhanced subaerial erosional unconformity of the Barremian-Lower Aptian Requienid limestones and are covered by the Upper Cretaceous Rudistid li…
Evidence of aerial volcanic activity during the Valanginian along the northern Tethys margin.
2009
7 pages; International audience; Stratigraphic measurement and sampling on three sections (Vergol, La Charce, and Montclus) through Valanginian deposits from the Vocontian Basin (southeastern France) reveals the occurrence of centimetre thick ochre-coloured layers, which can be correlated from one section to another. At least twelve of these are identified in sediments dated from the Pertransiens to Furcillata ammonite Zones. These horizons appear similar to previously described Oxfordian and Aptian bentonites, also from the Vocontian Basin. Clay-mineralogical and geochemical data are similar in the Valanginian ochre horizons and their enclosing marls except in one of these that shows a cla…
Report on the 4th International Meeting of the IUGS Lower Cretaceous ammonite working group, the "Kilian Group" (Dijon, France, 30th August 2010).
2011
8 pages; International audience; The 4th Kilian Group meeting (Dijon, France, 30th August 2010) focused on the Aptian and Albian Stages. For the Aptian, a two-fold division of the stage was adopted for the Mediterranean area with a boundary between the Dufrenoyia furcata and Epicheloniceras martini Zones. The main changes to the zonal scheme concern the Lower Aptian with: the introduction of a Deshayesites luppovi Subzone in the upper part of the Deshayesites oglanlensis Zone; the replacement of Deshayesites weissi by Deshayesites forbesi as new indexspecies of the second interval zone; the introduction of a Roloboceras hambrovi Subzone in the upper part of the D. forbesi Zone; and the subd…
Un exemple de spéciation lié à l'eustatisme: l'apparition précoce de Schackoina cabri (foraminifère planctonique mésogéen)
1997
Investigation of planktic foraminifers from the Lower Aptian of the Vocontian Basin (SE France) reveals that Schackoina cabri makes a very discrete first appearance in the Weissi ammonite zone and not in the Deshayesi zone, i.e. before the global anoxic event OAE 1a and not after as was accepted in the literature. This discovery seems to support the recent model whereby speciation of planktic foraminifers occurred in marine lowstands and their real expansion during the ensuing sea-level rise.
Palaeoceanographic significance of the Tethyan ‘Livello Selli’ (Early Aptian) from the Hybla Formation, northwestern Sicily: biostratigraphy and high…
2002
High-resolution micropalaeontological and chemostratigraphic records for the Hauterivian–Aptian succession outcropping at Calabianca (NW Sicily) provide new insight into the palaeoclimatic and palaeoceanographic evolution of the Tethys Ocean. Calcareous nannofossil and planktonic foraminiferal biostratigraphy together with δ13C chemostratigraphy allowed the identification of a hiatus in the Barremian and a major one including most of the Upper Aptian, the entire Lower Albian and part of the Middle Albian. The Livello Selli equivalent was identified on the basis of lithology and well constrained by calcareous plankton biostratigraphy as well as by the δ13C curve. The multi-proxy record from …
Paléoenvironnements et caractérisation des roches mères pétrolières des séries pré-salifères du bassin intérieur du Gabon
2003
Resume Le bassin interieur du Gabon, dont l'histoire est liee a la separation des continents Sud-Americain et Africain, comprend des depots continentaux fluvio-lacustres, localement glaciaires, dates du Precambrien superieur a l'Aptien p.p., surmontes par des facies marins aptiens et albiens. L'analyse par pyrolyse Rock–Eval d'echantillons d'affleurements et de forages preleves dans ce bassin met en evidence la presence de facies siliciclastiques riches en matiere organique (jusqu'a 25 % de carbone organique total) de types I et II. Ces niveaux, qui se rencontrent dans le Permien, le Neocomien-Barremien ainsi que dans l'Aptien, constituent d'excellentes roches meres et sont a l'origine des …
Evolution tectonique méso-cénozoïque du bassin de Paris: contraintes stratigraphiques 3D
2000
Abstract 3D stratigraphic geometries of the intracratonic Meso-Cenozoic Paris Basin were obtained by sequence stratigraphic correlations of around 1 100 wells (well-logs). The basin records the major tectonic events of the western part of the Eurasian Plate, i.e. opening and closure of the Tethys and opening of the Atlantic. From earlier Triassic to Late Jurassic, the Paris Basin was a broad subsiding area in an extensional framework, with a larger size than the present-day basin. During the Aalenian time, the subsidence pattern changes drastically (early stage of the central Atlantic opening). Further steps of the opening of the Ligurian Tethys (base Hettangian, late Pliensbachian;...) and…