The last deglaciation in the south Adriatic sea: biostratigraphy and paleoceanography

Abstract

The frequency patterns of planktonic foraminifera from four cores (AD91-14, AD91-16, AD91-17 and IN68-5), drilled in the South Adriatic Sea, allow us to subdivide the last deglaciation into 8 intervals. These intervals, calibrated with 14C AMS dating and isotopic stratigraphy, provide a detailed biochronoiogy for this basin. The oxygen isotopic records obtained from the planktonic foraminifera G.bulioides from the cores AD91-17, IN68-5 and IN68-9 show for the South Adriatic Sea the same palaeo-cli-matic trend documented in the North Atlantic ocean. In fact the two main steps of the deglaciation are very well identified, corresponding to Termination IA and IB as well as the Younger Dryas cold event. The δ13C record is more sensitive to local oceanographic conditions. Furthermore, isotopic records, biostratigraphic curves and 14C AMS datings record the beginning of deglaciation at 13.500 years B.P., the subdivision of the Younger Dryas into two "paleoclimatic phases", and confirm the presence of the sapropelitic layer S1.