A new study pushing the date of Aboriginal arrival in Australia back to about 65,000 years ago will fuel the debate over human origins.
The research, published this week in the British journal, Nature, bolsters the case that the ancestors of the first Australians could have interbred with archaic humans, such as the Denisovans, thought to be close cousins of the Neanderthals.
It also suggests ancient Australians were much more sophisticated than previously thought, and could have had a big impact on the environment.
Academics have long argued over the date of first Aboriginal landfall on Australia. Teams including dating specialist Richard Roberts, now at the University of Wollongong, dropped bombshells in the 1990s by reporting dates up to 60,000 years old for northern sites. Roberts is a co-author of this latest paper.
Academics continue to bicker, however, with some favouring dates as recent as 47,000 years.
In this new study, a team led by Chris Clarkson, of the University of Queensland, reports the Madjedbebe rock shelter, previously called Malakunanja II, in the Arnhem Land region of Australia’s Northern Territory, is up to 65,000 years old.
Clarkson’s team dug the site, within the traditional lands of the Mirarr people, in 2012 and 2015, retrieving more than 10,000 artefacts from the basal levels.
Hatchets for hunting, seed grinding stones for food processing and ochre “crayons” for art were among the objects collected.
The multidisciplinary team included the University of Wollongong’s Zenobia Jacobs, who deployed the optically stimulated luminescence dating method on single grains of sand associated with the material at the lowest levels. The scientists used radiocarbon dating on organic matter from higher layers.
“It confirms the deep-rooted connection to country of Aboriginal and Torres Strait Islander people,” Roberts told Cosmos. “It [the period of occupation] stretches back more than 2,000 generations.”
Claudio Tuniz, a dating expert outside the research team, said the diversity of artefacts pointed to a “complex culture that could have been generated and sustained only by relatively large social groups”.
The people would have had ample time to alter the landscape through the extinction of the continent’s giant marsupials, reptiles and birds called the megafauna.
The new dates increase the possibility of interbreeding between Homo sapiens and other early human species in the region, added Tuniz, a dating specialist at the University of Wollongong and the Abdus Salam International Centre for Theoretical Physics, in Italy.