Environmental and climatic response during the Middle Eocene Climatic Optimum in the western Tethys (Baskil section, Turkey)

The Middle Eocene Climatic Optimum (MECO) is a global warming event that occurred at about 40 Ma and lasted ~500 kyr. Despite being well documented in all the oceanic basins, the origin of the warming conditions related to the MECO is still controversial. The Baskil section, from eastern Turkey, encompasses an expanded and well-preserved record of the MECO in the western Tethys, yielding a highly detailed multi-proxy dataset. In this work, we present geochemical, mineralogical, environmental magnetic, micropaleontological, and sedimentological data from the Baskil section, unravelling the major paleoenvironmental changes that occurred in this region during the MECO. Stable isotopes data from surface, thermocline, and bottom dwelling foraminifera show that ocean warming was associated with a C-cycle perturbation, probably related to a period of high climatic instability. This induced hot and humid conditions, as well as major circulation re-arrangement in the western Tethys. These changes were also accompanied by a major sea-level fluctuation that triggered carbonate platform destabilization and re-sedimentation of neritic material.