Early silcrete heat treatment in Central Australia: Puritjarra and Kulpi Mara

Abstract

Heat treatment of stone for tool making has important implications for our understanding of the early human history of the Australian continent. New data on the antiquity of Australian heat treatment and its evolution through time in different regions have posed questions about the origin and temporal stability of technical practices. In this paper, we present the first evolutionary sequence of the use of heat treatment in Central Australia, with a trend to lower levels of heat treatment over time. Different trends are found in other regions across Australia: on the eastern seaboard, heat treatment became more prevalent over time, while in the inland, semi-arid Willandra lakes region heat treatment gradually disappeared over time. In central Australia, the long-term trend is towards fewer heat-affected specimens over time, but this happens in a single transition from stable high levels in the Pleistocene to stable moderate levels in the Mid- to Late Holocene. These evolutionary trends are consistent with regional diversification, reflecting adaptations to local conditions, and are not consistent with technological uniformity across the continent.