0000000000411878
AUTHOR
Monique Mettraux
Succession des faunes d'Ammonitesdu Sinémurien et du Pliensbachien dans les Préalpes médianes de Suisse romande (Vaud et Fribourg)
Resume L'analyse biostratigraphique et paleontologique des ammonites du Sinemurien et du Pliensbachien des Prealpes medianes de Suisse romande, permet de reconnaitre 15 horizons biostratigraphiques. Ils sont aisement correlables avec la zonation standard de l'Europe moyenne. Pour le Sinemurien superieur il existe des elements de comparaison tant avec la partie orientale de la nappe des Prealpes medianes (Langenegggrat, region de Thoune, Suisse) qu'avec sa partie meridionale (Chablais et klippes de Savoie, France). En effet, les faunes sont tres proches de celles de la region etudiee ici. Comme au Langenegggrat (Prealpes bernoises) et dans la plupart des gisements du Chablais (Savoie), les f…
Evolution tectonique méso-cénozoïque du bassin de Paris: contraintes stratigraphiques 3D
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…
Episodic deposition of the Lias in the Medianes nappe (western Switzerland): a record from mineralized ammonite-bearing beds
Abstract Sinemurian and Pliensbachian depositional sequences from the starved distal northern continental margin of the Tethys are preserved in the Medianes Nappe (Western Swiss Prealps). They contain mineralized beds which include a variety of facies. The northern continental margin of the Tethys was broken into blocks, less than 50 km wide, during an extensional phase. The Sinemurian and Pliensbachian sediments in the study are vary in thickness from less than 50 m in the north to more than 200 m in the south. Although the upper Sinemurian to Pliensbachian mineralized beds are thin, between 0.10 and 0.50 m thick, they commonly contain several distinct faunal horizons stacked one upon anot…