Search results for "Ammonite"
showing 10 items of 96 documents
Middle and Upper Jurassic record in the Western Sicily successions
2015
Middle-Upper Jurassic successions cropping out in western Sicily have been the subject of detailed sedimentological, stratigraphic and palaeontological studies over the last 15 years based on the analysis of ammonite associations. Studies are preferentially focused on the Bathonian-Tithonian chronostratigraphic interval. Some studied successions represent the type-locality of many ammonite species defined by G.G. Gemmellaro, while others have been known only in Sicilian geological literature. The examined sequences were sedimented in different depositional environments (moderately deep external carbonate platform) called Domains, more precisely, the Trapanese and Saccense Domains (TP, Trapa…
Support for a Vraconnian Stage between the Albian sensu stricto and the Cenomanian (Cretaceous System)
2008
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…
Early–middle Jurassic lytoceratid ammonites with constrictions from Morocco: palaeobiogeographical and evolutionary implications.
2008
13 pages; International audience; The ammonite genus Alocolytoceras Hyatt, 1900 is an uncommon lytoceratid with distinctive shell ornament. A set of 58 specimens, recently collected at Amellago in the central High Atlas (Morocco), has enabled us to trace a succession of three species over eight biozones from the Toarcian to the Aalenian. Two specimens from the Lusitanian Basin are added for comparison. Following a review of the genus, based on original specimens and data from the literature, seven species are considered valid. A palaeobiogeographical synthesis of 13 regions demonstrates irregular distribution patterns over time, with a constant presence in the south-west Tethys and an insta…
La transgression cénomanienne et l'âge des "Tourtias" du nord du bassin de Paris (F) et du bassin de Mons (B).
2010
29 pages; National audience
Les ammonites de l'Hettangien, du Sinémurien et du Pliensbachien inférieur de la Dorsale de Grande Kabylie (Algérie).
2008
Dommergues, Jean-Louis, Cattaneo, Gérard, Aïte, Ramdane, Gélard, Jean-Pierre (2008): Les ammonites de l'Hettangien, du Sinémurien et du Pliensbachien inférieur de la Dorsale de Grande Kabylie (Algérie). Geodiversitas 30 (3): 539-576, DOI: http://doi.org/10.5281/zenodo.5378393
Atlas des fossiles caractéristiques du Lias portugais III a) Domérien (Ammonites).
2007
45 pages; International audience; Ce fascicule est le troisième de l'Atlas des fossiles caractéristiques du Lias portugais; il fait suite au fascicule I consacré aux faunes du Lias Inférieur (Hettangien-Sinémurien) et au fascicule II dédié aux faunes de la première partie du Lias Moyen (Carixien). Le fascicule III est consacré à la deuxième partie du Lias Moyen, le sous-étage Domérien. Contrairement aux publications précédentes, le présent travail se restreint aux seules ammonites. Une cinquantaine d'espèces sont brièvement décrites et figurées. Les autres taxons (nautiles, bélemnites, brachiopodes, lamellibranches...) feront l'objet d'un prochain fascicule. Le but de l'Atlas des fossiles c…
Sinemurian to lowermost Toarcian ammonites of the Brescian Prealps (Southern Alps, Italy): preliminary biostratigraphical framework and correlations.
2009
10 pages; International audience; A set of 28 ammonite biohorizons or faunal assemblages is proposed for the Sinemurian, the Pliensbachian and the lowermost Toarcian of the Brescian Prealps, in part based on the published data of the authors of this contribution and partly on new results, derived both from recent field investigations and from the study of the historical collection of Lower Jurassic ammonites preserved in the Museum of Natural Sciences of Brescia (Northern Italy). The biohorizons are present in the Liassic carbonate succession of the Brescian Prealps, cropping out between the eastern surroundings of Brescia (Botticino), to the east, and Lake Iseo, to the west. Since the Hett…
Les bioévénements de la limite Albien (Vraconnien) - Cénomanien aux marges nord et sud de la Téthys (S.E. de la France et Tunisie centrale)
2007
International audience; 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)]
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.
Deux ammonites turoniennes rares du Tuffeau de Saumur (Maine-et-Loire) : Romaniceras (Romaniceras) kallesi badilleti subsp. nov. et Romaniceras (Yuba…
2009
10 pages; National audience