Stratigraphy of the Paleocene continental sedimentary succession of the northern Pyrenean basin (Corbières, southern France) using δ 13 C org 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 δ13Corg together with magnetostratigraphic and biostratigraphic data from a thick continental-dominated succession at Lairiere (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 δ13Corg events and assigns them to global δ13C 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. Supplementary material: Palaeomagnetic results, geochemistry details and palynological analysis are available at https://doi.org/10.6084/m9.figshare.c.4871214