Refined bio- (benthic foraminifera, dinoflagellate cysts) and chemostratigraphy (delta¹³C_org) of the earliest Eocene at Albas-Le Clot (Corbieres, France): implications for mammalian biochronology in Southern Europe

Utilizing bio- and chemostratigraphy, we propose an integrated dating of the upper part of the continental “Sparnacien des Corbières” and the overlying marine “lower-middle Ilerdian” succession of AlbasLe Clot (Corbières, France), in order to refine the position and age of the Le Clot mammalian locality. Our data show that this locality, which has yielded a mammal fauna early Ypresian in age (close to MP7, Mammal Paleo gene level), is located above the end of the carbon isotope excursion (CIE) the base of which defines the Paleocene–Eocene boundary. The Le Clot mammalian locality is therefore younger than the Paleocene–Eocene Thermal Maximum (PETM), and also younger than the Dormaal MP7 reference fauna in Belgium, which is correlated with the onset of the CIE (nannoplankton Zone NP9b). Moreover, we demonstrate that the Le Clot mammalian locality is older than the Eocene Thermal Maximum 2 (ETM2) event, located in the lower part of NP11 Zone. Associated with the ages of benthic foraminifera and dinocysts observed in the succession, our d13Corg chemostratigraphy suggests that the Le Clot locality is correlated to the upper NP10–lower NP11 Zones. The refined location of the CIE in the Albas-Le Clot section is discussed because two carbon isotope excursions are potentially recorded in the upper “Sparnacien des Corbières”, here recognized as mainly Thanetian in age