Stratigraphy of the Paleocene continental sedimentary succession of the northern Pyrenean basin (Corbières, southern France) using δ13Corg isotopes

Abstract : Continental-dominated successions are often poorly constrained stratigraphically due to a lack of robust biostratigraphic markers. This study provides the first dataset of δ 13 Corg together with magnetostratigraphic and biostratigraphic data from a thick continental-dominated succession at Lairière (northern Pyrenees, France). This section encompasses the latest Cretaceous up to the Paleocene-Eocene Thermal Maximum interval and is characterized by fluvial deposits, occasionally intercalated with continental carbonates, lacustrine deltaic deposits and shallow marine sediments. This work identifies δ 13 Corg events and assigns them to global δ 13 C geochemical events defined in Pyrenean and Tethyan marine successions, in which the stage boundaries are well calibrated. As the isotopic measurements are performed on dispersed organic matter in sedimentary rocks with a low organic content, we propose that analyses of the signal should take into consideration the depositional environment because variations in the organic matter content might affect the signal. We establish a high-resolution chronostratigraphy in terrestrial Paleocene deposits in the NE Pyrenean zone, recognize a late Selandian interval and define the Paleocene-Eocene Thermal Maximum event.