The Cretaceous deposits of the Paris Basin

Abstract

Abstract Since the creation of the Cretaceous system by Jean-Baptiste d'Omalius d'Halloy, numerous analyses have provided details about the Cretaceous sedimentary successions of the Paris Basin, where many boreholes have been drilled. We present a synthesis of the Cretaceous deposits using data from recent drilling carried out in the central and eastern parts of the basin which, during the early Cretaceous, corresponded to a continental environment represented by Wealden facies. However, from the Berriasian to the Barremian, the southeastern part of the basin was occasionally invaded by a shallow sea during transgressions originating from the Tethys Ocean. The sedimentary successions of this age presented in this article have been studied thanks to drilling carried out by Andra (French Agency for Nuclear Waste Disposal). Several new results are presented here: a discussion on the age of the Argiles ostréennes, the identification of an equivalent of oceanic anoxic event (OAE)1a, and the construction of a continuous section of the Albian clays in their type area. Regarding the Upper Cretaceous chalk, the Cenomanian to Maastrichtian stages are represented over the entire basin and correlations are proposed based on biostratigraphic data and various marker beds including marly levels, bentonites, hardgrounds and eco-events.