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Australia’s Arid Zone Settled 10,000 Years Earlier

Humans arrived in Australia about 50,000 years ago but the timing of their settlement in arid regions and cultural innovation has been uncertain. Now the Warratyi Rock Shelter in the desert region of South Australia’s north has revealed that humans occupied Australia’s arid interior and began developing sophisticated tools around 49,000 years ago – 10,000 years earlier than previously documented.

The discovery, published in Nature, is the oldest evidence of Aboriginal occupation in South Australia, and reveals new insights into modern human colonisation of Australia, unique cultural innovation, and interaction with now-extinct megafauna.

The project was led by arid zone research archaeologist Giles Hamm, an Honorary Fellow of the South Australian Museum and La Trobe University PhD candidate, with University of Adelaide geochronology specialists Dr Lee Arnold and Prof Nigel Spooner, geomorphologist Dr Peter Mitchell, and other researchers from Flinders University and The University of Queensland. They have worked for the past 9 years with the Adnyamathanha people in the Flinders Ranges.

The study suggests that people settled in the arid interior within a few millennia of arriving on the continent, and developed key technologies and cultural practices much earlier than previously thought for Australia and South-East Asia.

The team found that humans occupied the site from 49,000 to 46,000 years ago, and that objects recovered from the various layers of sediment represent the earliest-known use in Australia of various technologies including worked bone tools (40,000–38,000 years ago), stone tools modified for attachment to a handle (30,000–24,000 years ago), and the use of red ochre as a pigment (49,000–46,000) and gypsum (40,000–33,000 years ago).

“One of the key strengths of this study is the chronology, which has typically proved to be a contentious issue at early archaeological sites in Australia,” Arnold said. “We have used a range of complementary dating techniques and targeted different types of materials to ensure that the age of the site is reliably known.”

The team applied single-grain optically stimulated luminescence dating to determine when the fossil- and artefact-bearing sediments were deposited. Combined with statistical techniques, they were able to determine a precise occupation history for the archaeological site.

“The Warratyi Rock Shelter is a remarkable discovery showing aboriginal settlement of the Australian arid zone long before the last ice age and contemporaneous with iconic Australian megafauna, and revealing an innovative material culture, including the utilisation of ochre pigments, much earlier than previously recorded for Australia and South-East Asia,” Spooner said.