A land mass that was once home to up to half a million people has been discovered off the coast of northern Australia.
The now-submerged continental shelf was a vast, habitable landscape for most of the past 65,000 years, covering about 390,000 square kilometers (about 242,300 miles)—an area larger than New Zealand
The scientists who made the historic discovery, led by Kasih Norman of Queensland’s Griffith University, said the “complex landscape” that existed on Australia’s northwest shelf was “unlike any landscape found on our continent today”.
And yet, the people who lived there spoke similar languages and created similar styles of rock art to those who lived in the surrounding areas, the team announced in a press release.
These regions, which were once connected by the shelf, still exist now: West Arnhem Land in the north and the Kimberley in the northwest.
Norman and her colleagues explained that when the last ice age ended about 18,000 years ago, global warming caused sea levels to rise, which submerged some of the world’s continents.
This split the supercontinent of Sahul into New Guinea and Australia and detached Tasmania from the continent.
A map showing where the continent of Sahul once stood(Kanguole via Wikipedia)
Australia’s now submerged continental shelves were thought to be environmentally unproductive and so neglected by the original indigenous communities.
“But increasing archaeological evidence shows that this assumption is incorrect,” the researchers write.
“Many large islands off the coast of Australia – islands that once formed part of continental shelves – show signs of occupation before sea levels rose.”
However, before Norman and her team conducted their investigations, archaeologists had only been able to speculate about the nature of these pre-Ice Age sunken landscapes and the size of their populations.
But the newly published findings have filled in many of the missing details – revealing that the Northwest Shelf was a lush realm, with archipelagos, lakes, rivers and even a vast inland sea.
“The region contained a mosaic of fresh and saltwater habitable environments,” they said. “The most prominent of these features was the inland sea of Malita.”
This sea has existed for 10,000 years (27,000 to 17,000 years ago), with an area of more than 18,000 square kilometers, according to archaeologists.
A map of the shelf showing various geological features(US Geological Survey.)
The Northwest Shelf could have supported between 50,000 and 500,000 inhabitants at various times over the past 65,000 years, according to modeling conducted by Norman and her team.
The population would have peaked at the height of the last Ice Age, about 20,000 years ago, when the entire shelf was dry land.
To draw their conclusions, the researchers projected past sea levels onto high-resolution maps of the ocean floor.
They found that low sea levels exposed a vast archipelago of islands on the northwestern Sahul shelf, stretching 500 kilometers toward the Indonesian island of Timor.
This archipelago appeared between 70,000 and 61,000 years ago, and remained stable for about 9,000 years.
“Thanks to the rich ecosystems of these islands, people may have migrated in stages from Indonesia to Australia, using the archipelago as stepping stones,” the scientists noted.
“With the descent into the last Ice Age, the polar ice caps increased and sea levels fell by up to 120 meters. This fully exposed the shelf for the first time in 100,000 years.”
Left: A satellite image of the submerged Northwest Shelf region. Right: A map of the drowned landscape(US Geological Survey, Geoscience Australia)
However, at the end of this Ice Age, rising sea levels drowned the shelf, forcing its inhabitants to flee as the waters invaded the once productive landscapes.
“Retreating populations would have been forced to coalesce as available land shrank,” the experts write, noting that this resulted in the emergence of “new rock art styles” in the Kimberley and Arnhem lands.
“Sea level rise and the drowning of the landscape is also recorded in the oral histories of First Nations people from across the coastal zone,” they added, noting that these stories are thought to have been passed down for “over 10,000 years”. .
“This latest discovery of the complex and intricate dynamics of First Nations people responding to a rapidly changing climate lends increasing weight to the call for more Indigenous-led environmental management in this country and elsewhere,” they concluded the statement. Theirs.
“As we face together an uncertain future, deep-time indigenous knowledge and experience will be essential to successful adaptation.”
The full paper on their findings can be accessed via Quaternary Science Reviews.
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