YTTRIUM AND REE SIGNATURE RECOGNIZED IN CENTRAL MEDITERRANEAN SEA (ODP SITE 963) DURING THE MIS 6 – MIS 5 TRANSITION

The Mediterranean Sea acts as a miniature ocean with the development of its own conveyor belt. It constitutes an ideal location to study and forecast how the marine environment responds to rapid climatic change. Here we present a palaeoenvironmental study carried out on the sediments of ODP Site 963, recovered in the Sicily Channel, the sill which divides the western from the eastern Mediterranean basin. We focused on the transition between the penultimate glacial (MIS 6) and the last interglacial (MIS 5), between approximately 130 and 115 kyr BP. A novel approach is proposed, taking into account centennial-scale geochemical data on major elements, selected trace elements, and yttrium and REE (YREE). This approach was demonstrated to be suitable to recognize both environmental conditions existing during deposition of the studied sequences and to establish whether diagenetic modifications of the original geochemical signature occurred. Our results highlight the delivery of Fe-rich material to the basin, probably from the arid continental environment of southern Sicily. This phenomenon seems to be interrupted in coincidence with the development of Eemian forests at about 126–127 kyr BP in southern Europe. The deposition of weathered products suggests increate humidity in Sicily between 127 and 124 kyr BP. Less oxidizing/more productive conditions characterized the Sicily Channel sea floor between 124 and 119 kyr BP, while sapropel S5 was depositing in the eastern Mediterranean. They are evidenced by the enrichment of heavy REE, the decrease in positive Ce anomaly, and a slight increase in excess barium. This implies that oceanographic processes which led to bottom anoxia in the eastern Mediterranean might have had an impact even on the Sicily Channel environment.