IONIAN SEA SURFACE TEMPERATURE DURING THE SAPROPEL S1 DEPOSITION INFERRED FROM PLANKTONIC FORAMINIFERAL Mg/Ca AND δ18O

Abstract

Temperature variations during the Holocene sapropel S1 has been investigated by means of a multiproxy study on core ET99-M11 collected in the western Ionian Sea at a water depth of 2800 m. Sea Surface Temperatures (SST) reconstruction has been made by measuring oxygen stable isotopes (δ18O) and Mg/Ca ratios on the planktonic foraminifers Globigerinoides ruber and Globigerina bulloides. Results indicate that the investigated interval was characterized by water temperature increase, both at surface and in the sub-surface layers. Paleotemperature reconstruction based on Mg/Ca ratios shows higher temperature values during the two sub-units (S1a and S1b) of the sapropel S1, and lower during the sapropel interruption, the latter being synchronous to the well known 8.2 cold event. In addition, a number of several short-term cold oscillations which can be correlated with millennial scale climate events in the North Atlantic region is evidenced. This indicates a possible atmospheric connection between the Central Mediterranean and the North Atlantic region and the strong relation between climate and oceanographic changes during the sapropel deposition