CLIMATE VARIABILITY THROUGH MIS 20-MIS 19 IN CORE KC01B, IONIAN BASIN (CENTRAL MEDITERRANEAN SEA)

Abstract

High resolution quantitative analyses have been carried out on coccolithophore assemblages at the Ionian Sea core KC01B in the time interval crossing the deglaciation between Marine Isotope Stages 20 and 19 (Termination IX, in Lower-Middle Pleistocene). Principal Component Analysis emphasizes the temperature as the first environmental parameter affecting coccolithophore assemblages that reach a higher number of coccoliths per gram of sediment during the interglacial. Patterns of key taxa indicate the occurrence of a terminal stadial phase in the late MIS 20 when the presence of cold, turbid and low salinity surface waters in the Ionian Sea are highlighted by prominent peaks of Coccolithus pelagicus ssp. pelagicus, Gephyrocapsa muellerae >3 m, and increased abundances of Syracosphaera spp., Helicosphaera carteri, Rhabdosphaera spp. Enhanced reworked coccoliths and lithic elements are recorded in the samples during this phase, and they represent an useful tool to monitoring the amount of detrital input supply during low sea-level and major erosion process on land. Short-term warm and cool events through TIX are evidenced by the fluctuations of all these proxies anticipating the interglacial onset. The latter is marked by distinct surface water conditions suggesting the occurrence of an interval correlated to a sapropelic layer, and specifically to i-cycle 74. The comparison of these short-lived events with the climate pattern recently observed in the nearby Montalbano Jonico succession points to a shared Ionian Sea climatic and oceanographic pattern through TIX and allows to sustain a similar climate evolution recorded during the last deglaciation.