Transgressions-régressions, variations eustatiques et influences tectoniques de l'Aptien au Maastrichtien dans le Bassin de Paris occidental et sur la bordure du Massif armoricain

Abstract

Middle and Upper Cretaceous deposits studied in the western Paris Basin and on the Armorican Massif margin show seven transgressive pulses that can be detected in the geometrical arrangement of the sedimentary bodies and the vertical succession of facies. The transgressive episodes, each delimited by a regressive phase, reached their peak during: 1. (1) late Late Aptian —(Early Albian regression) 2. (2) mid Late Albian —(Late Albian-Early Cenomanian regression) 3. (3) mid Early Cenomanian —(late Early Cenomanian regression) 4. (4) late Middle Cenomanian —(Late Cenomanian regression) 5. (5) mid Early Turonian —(Coniacian regression) 6. (6) Santonian-Campanian —(Late Campanian regression) 7. (7) Maastrichtian —(Late Maastrichtian regression) The Cretaceous sediments occur as a series of sequences, separated by more or less important discontinuities and erosion surfaces. The features and distribution of these sequences have been studied in the nearshore region of terrigenous sedimentation and in the Chalk basin. An attempt is made to relate the bathymetric changes to either tectonic movements or more widespread eustatic oscillations.