ABSTRACT: The Triassic System is divided into 3rd-order sequences along a West to East transect on the 'W'estem Peritethyan margin in the Ardeche (South-East France Basin). The transect displays abrupt lateral variations, from proxhnal-continental to distal-marine environments, and marine ingressions have been recognized in clastic, carbonate and evaporitic facies. Biostratigraphic data in clastic series, provided by ichnofauna, microfossils and palynomorphs, enable us to characterize Anisian, Ladinian, Carnian and Rhaetian stages and to place the Ladinian/Carnian boundary. Abrupt variations in thickness and facies 'W'ere controlled by synsedimentary faulting. Despite these features, major boundaries and successions of backstepping and forestepping systems tracts enable correlations bet'W'een 3rd-order sequences in Ardeche and other domains in 'W'estem Europe, in particular in the German Basin. The main characteristics of the Ardeche series are 'W'ide onlaps over the crystalline basement during the Ladinian stage, despite the thinness of the series and occurrence of thick interbedded coarse-grained clastic and evaporitic high stands in the Upper Triassic strata.
2nd-order sequences have been identified follo'W'ing 4 marine ingressions in the transect. The proposed Ladinian peak transgression is charac¬terized by open-marine microfossils despite a clastic facies. Eustatic variations caused broad onlaps of backstepping series over a 'W'eakly subsiding Variscan M:assif Central until late Ladinian time. In the Late Triassic Epoch, from the Carnian age onvvards, mainly forestepping, thick clastic/ evaporitic series 'W'ere controlled by a more active tectonic subsidence.