The big news of the day on Thursday was that Australia was first settled 65,000 years ago, as reported today in The New Daily and around the world. But that claim is already proving a matter of controversy.
Critics are suggesting that the ancient settlement wasn’t the beginning of continuous human settlement – but rather represented a first wave of humans that didn’t survive.
The lead archaeologist of this new discovery, Professor Chris Clarkson of the University of Queensland, told The New Daily that the naysayers are simply mouthing sour grapes.
So it goes for archaeology: the world of Indiana Joneses beating the hell out of one another for the sake of a magic trinket.
The date when humans first came to Australia has long been contested, with estimates ranging from 47,000 to 60,000 years ago. The stakes are even higher in terms of broader human history, because Australian settlement has become a marker for when homo sapiens migrated out of Africa. People settled in Australia long before they headed for Europe.
The new dating of artefacts at Madjedbebe, the rock shelter in northern Australia, accepted as the site of earliest settlement on the continent, and celebrated for its ancient paintings, is rock solid.
Professor Clarkson for decades believed the Madjedbebe site was much older than previously thought. He enlisted Wollongong geochronologist Zenobia Jacobs – an international guru of dating ancient materials.
She used optically stimulated luminescence (OSL) dating technology to establish the age of 28,5000 individual grains of quartz from top to bottom layers at the dig site. The technology works by determining when light last struck each grain, and from that it’s known when it was buried.
From this it was determined that a stone axe was the oldest example of axe technology in the world.
So what’s the ruckus? Professor Alan Cooper of the University of Adelaide told New Scientist that he was perplexed by the discovery, because equally ancient artefacts haven’t been found elsewhere in Australia.
“We know these people were fast movers – they moved very quickly from Africa to Asia to Australia,” he said. “So if they did arrive in northern Australia 65,000 years ago, why did they then just sit down and wait 15,000 years before spreading to the rest of the country?”
One idea might be that they died out. Our emails to Professor Cooper weren’t answered; an automatic reply said he was abroad.
Another exciting aspect of Clarkson’s paper on the discovery – published in Nature – also pushed back the time when humans coming out of Africa mated with archaic species in Asia, such as Neandertals and Denisovans.
Living Aborigines carry traces of those two species’ DNA, which their ancestors must have acquired by mixing somewhere in Asia before they reached Australia.
Two US researchers, however, told Science that early mixing with Denisovans and Neandertals was at odds with genetic evidence from living Aborigines and nearby Melanesians. They claimed that analyses of these people’s DNA suggested that the interbreeding happened only 45,000 to 53,000 years ago. Jim O’Connell of the University of Utah in Salt Lake City, said: “I’d make the argument that the ancestor of [living] Australian Aboriginals and New Guineans got there later.”
Chris Clarkson, however, told The New Daily that there isn’t the genetic evidence to say one way or the other.
Dr Michael Westaway is a senior research fellow in the Research Centre for Human Evolution. In an email he told The New Daily: “I think we just don’t have enough genomic evidence to say much at all.”
Recent studies have been limited, he said, and “we don’t have any (ancient) DNA with the exception of one individual from Lake Mungo, not Mungo Man but another individual probably buried only 1000 years ago or so”.
Westaway said “jumping to the conclusion that it reflects a migration that for some reason disappeared I think it really just exposes how little we do know.’’
He says because of the sophistication of the artifacts, which number more than 10,000, and suggesting a thriving population, Westaway “can’t imagine this is a group that is then later on replaced”.