The record of the last deglaciation in two deep-sea cores from the Sicily Channel of Capo Rossello (central Meditteranean)

Abstract

Two cores raised by the Dutch R/V TYRO in 1993 from a water depth of 472 and 502 m in the Sicily Channel off Capo Rossello (Sicily) have been investigated from a sedimentological and micropaleontological point of view, and calibrated with 4 AMS datings. The area is flat-lying and is higher than the surrounding territory so that it cannot be reached by turbidity currents. The composition of the sediments is monotonous and uniform, with grey, fine to very fine silty mud as dominant lithology. The micropaleontological study of the sand-size sediment fraction allowed to identify the transition from the cold water "glacial" time to warm-water "postglacial" time, it also showed that - after the onset of deglaciation - a short duration episode characterized by cooler conditions occurred , tentatively attributed to the "Younger Dryas". A relative chronology was thus established for two cores, and the sedimentation rate was calculated, ranging from 20 to 30 cm/1000 y. High precision radiometric dating (AMS) on four samples selected from critical intervals of the longest core confirmed the relative chronology derived from the foraminiferal study and permitted to precisely locate the conventional Pleistocene/Holocene boundary. The age of the "Younger Dryas" is of approximately 12000÷13000 y. BP. The study was performed as part of the "Site Survey Package" for a drillsite planned for ODP Leg 160, which was successfully accomplished in 1995. Site 963 penetrated in the subbottom for 200 m and recorded an undisturbed, expanded succession of hemipelagic sediments ideally suited for high resolution paleoceanographic studies, and containing a strong paleomagnetic signal.