Changes in temperature and oxygen isotopic composition of Mediterranean water during the Mid-Pleistocene transition in the Montalbano Jonico section (southern Italy) using the clumped-isotope thermometer

International audienceTaking advantage of the recent clumped-isotope methodological developments, the present study focuses on the reconstruction of temperatures and seawater δ18O in the central Mediterranean Sea across the Mid-Pleistocene section from Montalbano Jonico (south of Italy). Our results suggest that Mg/Ca paleothermometer can be biased over several intervals, making clumped-isotope a promising choice to reconstruct past changes in seawater temperature and isotopic composition in the Mediterranean Sea. Our results provide the first clumped-isotope temperature and δ18OSW reconstruction across several glacial and interglacial Marine Isotope Stages from MIS 36 to MIS 19 in the central Mediterranean Sea.During the climatic optimums of MIS 31 and MIS 19, considered as close analogues to the current interglacial in terms of insolation forcing, reconstructed average sub-surface temperatures from benthic foraminifer analyses (13.8 ± 1.5 °C and 14.8 ± 1.3 °C, respectively) and isotopic composition of seawater (between 1.6 ± 0.4‰ and 2.0 ± 0.3‰) are similar to the ones measured today below the thermocline in the Gulf of Taranto. Our results show that bottom water conditions remained similar in all the studied glacial periods, with cold temperatures around ~ 8 °C in average. The lack of a clear cooling across the Mid-Pleistocene either suggest that glacial oceanographic conditions in the Mediterranean Sea remained relatively stable between the 41 ka-world and the 100 ka-world or that the tectonic uplift that took place during this transition balanced out the MPT cooling trend through the shallowing of the deposition site