Privat, Karen, Judith Field (Department of Archaeology, University of Sydney) and Clive Trueman (School of Earth and Environmental Sciences, University of Portsmouth)

Biogeochemical Contributions to the Megafaunal Extinction Debate

During the Late Pleistocene, over 20 genera of megafauna disappeared from the Australia-New Guinea landmass of Sahul. These extinctions broadly coincided with projected dates of human arrival. Some researchers support a human-mediated extinction model where large-bodied animals were rapidly driven to extinction between 50ka to 40ka, via over-hunting and habitat modification. Others point to climatic instability in the Late Pleistocene as a major driving force behind the megafaunal extinctions. At Cuddie Springs, stone artefacts are found in association with the bones of now-extinct megafauna in sediments dated from ~36ka to ~30ka, representing a human-megafauna overlap of at least 16ka. The prolonged co-existence of humans and megafauna at Cuddie Springs highlights the need to investigate the possible role of climate change in the decline of the Australian megafauna. The palynological evidence suggests that the phase of megafaunal decline and eventual disappearance from the fossil record (~30ka) coincided with the onset of a period of ephemeral lake conditions and increased grassland cover, followed by a period of pronounced aridity and extended dry lake conditions. The biochemical analysis of megafaunal bones and teeth from Cuddie Springs can provide us with further information about the environment in which these animals lived.

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