Central Mediterranean Mid-Pleistocene paleoclimatic variability and its association with global climate

Abstract

Planktonic foraminiferal assemblages were studied at high-resolution in core KC01B from the Ionian Sea. Quantitative analysis allowed us to distinguish the main climatic features and associated paleoceanographic changes, that occurred between Marine Isotopic Stages (MIS) 13 and 9 (~500-300 ka). MIS 12 and MIS 10 are characterized by relatively temperate conditions and an oligotrophic oceanographic regime in the early part and by colder conditions and nutrient supply in the sub-surface water masses in the upper part. During these intervals, small but distinct peaks of Neogloboquadrina pachyderma sinistral (sin) are detected at times of extremely negative values of the planktonic foraminifera paleoclimatic curve. Their co-occurrence with similar episodes in the Atlantic suggests that the climate in the Central Mediterranean was associated with north-Atlantic millennial-scale climate instability. MIS 11 and MIS 9 are dominated by surficial warm-water taxa. The climate optimum is reached in the middle part of each of these stages, as denoted by the presence of Globigerinoides sacculifer, and persists for approximately 20 and 6ka during MIS 11 and MIS 9 respectively. This warming is not constant but is characterized by three distinct intervals with elevated winter temperatures and/or weak winter mixing. Distribution of Globigerina bulloides, Turborotalita quinqueloba and N. pachyderma dextral (dex) indicates that significant environmental changes occur across the transitions from glacial to interglacial MIS 12/MIS 11 (Termination V) and MIS 10/MIS 9 (Termination IV). The studied record documents a close linkage between Mediterranean climate evolution and higher- and lower-latitude climate change throughout MIS 13-9.