Hydrological relationship between the North Atlantic Ocean and the Mediterranean Sea during the past 15-75 kyr

The Mediterranean Sea hydrology at the time of the Heinrich formation in th e North Atlantic Ocean was analyzed by comparing sea surface temperatures ( SSTs) and oxygen isotope composition of seawater (delta w) changes during t he past 75 kyr in two marine cores. These were compared to the palynologica l variations derived in the Mediterranean Sea core. During the last glacial the two oceanic SST records show similar and synchronous patterns, with se veral long-term cooling periods, ending by abrupt SST increases. At the tim e of the Heinrich events, cold SSTs and low salinity prevailed in the Medit erranean Sea. The freshwater budget was similar to the modern one, permitti ng the presence of a mixed forest on the Mediterranean borderlands. The pos t-Heinrich periods are marked by a freshwater budget decrease, limiting oak and fir tree growth in the Mediterranean region. Increase of precipitation or reduction of evaporation is observed before the Heinrich episode, and i s associated with a well-developed mixed Mediterranean forest.