Yahoo – AFP,
Martin PARRY, July 19, 2017
Aboriginal
people have been in Australia for at least 65,000 years, longer than previously
thought, roaming the area alongside giant megafauna, scientists said in a
finding that sheds fresh light on when modern humans left Africa.
Australian
Aborigines are believed to be custodians of the oldest continuous culture on
the planet, but when they first arrived has been a contested issue. Previous
estimates have ranged from 47,000 to 60,000 years ago.
A key site
in the debate is Madjedbebe, a remote rock shelter in northern Australia's
Kakadu region that is the oldest-known human occupation area in the country.
New
evidence uncovered by a team of archaeologists and dating specialists during a
dig there, including the oldest ground-edge stone axe technology in the world,
has pushed back their presence even further.
The findings,
published in the journal Nature this week, set a new minimum age for the
dispersal of modern humans out of Africa and across south Asia.
"It's
hugely significant in tying down what happened," the University of
Queensland's Chris Clarkson, the lead author who led the team that excavated
the site, most recently in 2015, told AFP.
"It
means that we can set the minimum age for modern humans coming out of Africa,
which until now has been a bit tenuous. We can now say with certainty that they
arrived in Australia 65,000 years ago."
New
evidence uncovered during a dig in Madjedbebe, a remote rock shelter
in
northern Australia's Kakadu region, sheds fresh light on when modern
humans
left Africa
|
It also
indicates that they arrived on the continent before the extinction of
Australian megafauna such as giant wombats, kangaroos and lizards.
In addition
to showing the deep antiquity of Aboriginal occupation, the dig also revealed
evidence of activities and complex lifestyle, including flaked stone tools and
grinding stones.
"The
site contains the oldest ground-edge stone axe technology in the world, the
oldest-known seed-grinding tools in Australia and evidence of finely made stone
points which may have served as spear tips," said Clarkson.
"Most
striking of all in a region known for its spectacular rock art are the huge
quantities of ground ochre and evidence of ochre processing found at the site,
from the older layer continuing through to the present."
It was
clear the population was "technologically sophisticated".
First
major water crossing
Some 11,000
artefacts were discovered in the lowest layer from the 2015 dig, with the team
carefully assessing the position of each one to ensure they matched the ages of
the sediments in which they were found.
Extensive
dating by optically stimulated luminescence methods -- which estimates the time
since mineral grains were last exposed to sunlight -- showed a general pattern
of increasing age with depth, and provided a timeframe that the scientists said
was far more accurate than before.
The new
dates for Madjedbebe fit well with genetic analyses indicating modern humans
left Africa between 60,000 and 80,000 years ago.
At that
time, there were much lower sea levels and the crossing distance from the
islands of Southeast Asia to Australia was shorter than today.
"This
would have been the first major water crossing ever by humanity," said
Clarkson.
The Mirarr
clan, traditional owners of large parts of Kakadu and western Arnhem Land, have
now closed access to Madjedbebe, but applications have been made by
archaeologists to examine other sites in the area to see if they have the same
sequences.
"This
study confirms the sophistication of the Australian Aboriginal toolkit and
underscores the universal importance of the Jabiluka area," said Justin
O'Brien, chief executive of the Gundjeihmi Aboriginal Corporation, which works
to advance the interests of the Mirarr.
"These
findings reinforce the need for the highest level of conservation and
protection for this site."
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