GSA Connects 2021 in Portland, Oregon

Paper No. 33-10
Presentation Time: 4:10 PM


MURRAY, John1, HIRNIAK, Jayde1 and ZIPKIN, Andrew M.2, (1)School of Human Evolution and Social Change, Institute of Human Origins, Arizona State University, Tempe, AZ 85281, (2)School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85281

Accurately sourcing silcrete material from archaeological sites is important for understanding lithic raw material exploitation by early human populations in South Africa. Identifying specific sources of lithic raw material can provide information on how far past populations traveled to obtain these materials and source exploitation criteria, which can be influenced by multiple factors such as availability, raw material quality, group territoriality, and exchange networks. Silcrete is widely used for stone tool manufacture throughout much of the world and is sometimes heat-treated to improve flaking quality. Despite its importance for investigating prehistoric resource exploitation, we have only a minimal understanding of how heat treatment impacts the geochemistry of silcrete and how this varies between and within sources. This is particularly important in South Africa where heat-treated silcrete artifacts are common during the later Middle Stone Age. Previous studies concluded that specific elements (e.g., Cu and Cs) should be omitted from all statistical analyses of compositional data due to minimal understanding of how these elements are affected by heat-treatment. However, a larger comparative dataset is necessary to fully understand these changes. Here, we examine how heat treatment affects the elemental composition of silcrete from three sources near the Pinnacle Point site complex in South Africa. We selected five unheated and five experimentally heat-treated silcrete samples from each source (n = 30) for atomic spectroscopy. The results of this work will inform future provenience studies of silcrete artifacts and facilitate better understanding of lithic resource use among early humans living near Pinnacle Point.