NEW PERSPECTIVES ON PREHISTORIC HUMAN-ENVIRONMENT INTERACTIONS IN THE AUSTRALIAN ARID ZONE

Interpretations of changes in patterns of landscape use by Aboriginal people in the Late Holocene, particularly the dramatic increase in the number of archaeological sites that date to this period, assume that the record of hunter-gatherer activity (largely stone artefacts) has accumulated on stable landsurfaces. However, the geomorphological record of the Late Pleistocene and Holocene suggests otherwise. Research undertaken over the past seven years in arid western NSW, Australia, demonstrates that the landsurfaces, particularly the valley floors of ephemeral stream systems upon which stone artefact scatters and associated heat-retainer hearths are found, have been anything but stable. The record of landscape evolution that is preserved within the sediments of the valley fills is one of episodic disequilibrium, with prolonged gaps in the sedimentary record reflecting erosion-dominated geomorphic regimes.

In this paper, we examine regional patterns in the Holocene geomorphological record in western NSW and the relationships between this and the temporal pattern of the archaeological record as determined from radiocarbon dating of charcoal from heat-retainer hearths. Relatively short occupation histories, of a few hundred to less than a thousand years, are found in places where geomorphological processes have been active in removing accumulations of sediments from the valley floors. Much longer patterns, up to 6,000 years, are found on more stable surfaces remote from stream margins. This has implications for the perceived increase in site numbers after the mid Holocene (the so-called "intensification theory") as well as changes in site structure and content. We conclude that any interpretation of the archaeological record that assumes landscape stability throughout the Holocene - and therefore a continuous record of Aboriginal occupation - may need to be reconsidered.