Ecosystem change during MIS4 and early MIS 3: Evidence from Middle Stone Age sites in South Africa

Abstract

Several Middle Stone Age (MSA) site in southern Africa present evidence of environmental changes during Marine Isotope Stages (MIS) 4 and 3 between 70ka and 50ka. Of these, Sibudu Cave, KwaZulu-Natal, has yielded a detailed record of how globalscale climate change events manifest locally. During MIS 4 (70ka to 60ka) conditions were similar to those during the Last Glacial Maximum. During the transition between MIS 4 and MIS 3 at around 60ka the Sibudu environment changed from a predominantly forested community to more open grass/woodland mosaic. Other MSA sites from across South Africa provide complementary palaeoenvironmental proxy data but imprecise dating presents a cross-correlation challenge. Archaeological sites on the western portion of South Africa appear to have been abandoned earlier and for longer than sites in the East, most likely as a result of adverse climatic conditions. Regional scale climate events in southern Africa are driven by ocean/atmosphere interactions, and at this time weakening of the palaeo-Agulhas Current and an eastward shift of the Agulhas Retroflection resulted in lower sea surface temperatures and a corresponding decrease in humidity and rainfall.