Middle and Late Pleistocene paleoscape modeling along the southern coast of South Africa

Abstract

Changing climates, environment, and sea levels during the Middle and Late Pleistocene must have had significant impacts on early modern humans and their behavior. However, many important archaeological sites occur along the current coastline of South Africa where the gradual slope of the offshore Agulhas Bank meant that small changes to sea level height potentially caused significant shifts in coastline position. The geographic context of these currently coastal sites would have been transformed by sea level shifts from coastal to near-coastal to fully terrestrial. To understand human adaptations as reflected in the archaeological deposits of these now-coastal sites we need to accurately model coastline position through time. Here, we introduce a Paleoscape model as a conceptual tool to ground the records for human behavioral evolution within a dynamic model of paleoenvironmental changes. Using integrated bathymetric datasets, GIS, and a relative sea level curve we estimate the position of the coastline at 1.5 ka increments over the last ~420,000 years. We compare these model predictions to strontium isotope ratios from speleothems as an independent test and then compare the coastline predictions to evidence for shellfish exploitation through time. Both tests suggest our model is relatively robust. We then widen our paleoscape model to most of the Cape region and compare the predictions of this broadened model to evidence from Blombos cave. © 2010 Elsevier Ltd.