Anomalous SST warming during MIS 13 in the Gulf of Lions (northwestern Mediterranean Sea)

During the PROMESS campaign (summer 2004) a borehole (PRGL1) was drilled in the upper slope of the Gulf of Lions covering the last 530 kyr. Here, we present new biomarker data from 440-528 kyr in order to reconstruct past climate variability, sea surface temperature (SST) (alkenone-based) and oxygenation of the bottom waters (based on n-hexacosanol and n-nonacosane ratio) during Marine Isotope Stages (MIS) 12 and 13. Contrary to southern paleorecords, MIS 13 showed the warmest SST values of the past 530 kyr in the Gulf of Lions, which is in agreement with recent findings in northern continental paleorecords. Our data suggest that the ice volume in northern latitudes and its effect on Inter-Tropical Convergence Zone (ITCZ) position during winter caused the anomalous warming in the northwestern Mediterranean during MIS 13. Moreover, the northward incursion of the ITCZ could have modified the stadial reinforcement of north-westerly winds documented from MIS 11 to the present.