High-resolution bio- and chemostratigraphy of an expanded record of Oceanic Anoxic Event 2 (Late Cenomanian–Early Turonian) at Clot Chevalier, near Barrême, SE France (Vocontian Basin)

A newly located exposure of the Niveau Thomel, an organic-rich level at the Cenomanian–Turonian boundary, provides a highly expanded record of Oceanic Anoxic Event (OAE) 2. The new locality, close to Barrême in the Vocontian Basin, SE France, is developed in deep-water hemi-pelagic facies (marls, chalks, organic-rich shales) and provides an improved understanding of palaeoceanographic events associated with OAE 2. Investigation of the biostratigraphy (nannofossils and planktonic foramininfera), organic and inorganic geochemistry (bulk carbonate δ18O, total organic carbon (TOC), bulk organic, biomarker-specific and carbonate δ13C, major and trace elements, and Rock-Eval data) has allowed characterization of the sediments in great detail. The combined study further constrains the detailed relationship between bio- and chemostratigraphy (particularly stable carbon isotopes) for this interval, and provides new evidence confirming the importance of the Plenus Cold Event, a short interval of global cooling, increase in oxygenation of bottom waters, and drop in pCO2 that occurred during the early part of OAE 2 as the consequence of organic carbon burial.