Divers found a treasure trove of Aboriginal tools on a lost chunk of the Australian continent, which sunk underwater thousands of years ago

Aylin WoodwardJul 3, 2020, 01:44 IST

The Cape Bruguieres Channel and surrounding landscape of Murujuga.Jerem Leach

In a new study, researchers describe 270 Aboriginal artifacts they found at two underwater archaeological sites off Australia's northwest coast.
The stone tools are at least 7,000 years old.
The artifacts were underwater because sea levels rose and submerged 30% of Australia's coast line at the end of the last Ice Age 12,000 years ago.

Australia was nearly one-third bigger 12,000 years ago.

But when glaciers melted at the end of the last Ice Age, sea levels rose sharply, engulfing 770,000 square miles of the continent's coastline. Places inhabited by the Aboriginal people sunk beneath the waves, burying tools and other artifacts at sea.

Some of that lost heritage was recently found.

A study published Wednesday describes how researchers located these ancient underwater archaeological sites — the first ever found in Australia — and what they recovered there: 269 Aboriginal artifacts that were at least 7,000 years old and one artifact that was at least 8,500 years old.

"This discovery redrew the map of what archaeology can do on this continent," Jonathan Benjamin, an archaeologist at Flinders University and lead author of the study, told Business Insider. "We've demonstrated that if you look in the right places, you can find archaeological evidence that survived rising sea levels."

The findings offer unprecedented new insights into the lifestyle and culture of the Aboriginal people thousands of years ago. The following photos show how Benjamin's team dove down to survey and collect the underwater artifacts.

Before the seas rose, Australia's coastline extended 100 miles further than it does today. So it's likely many ancient Aboriginal sites are underwater.

A boat docked off the shore of North Gidley Island, to the south of the Cape Bruguieres Channel in northwestern Australia. Jerem Leach

Finding those submerged sites can be challenging. It took Benjamin's team three years to pinpoint the two underwater areas where they recently found the trove of tools.

Archaeologists Jonathan Benjamin and Madeline Fowler photograph an artifact found in an Australian intertidal zone. Sam Wright

Finally, the team sent divers down to investigate an area known as the Cape Bruguieres Channel in 2019.

Maritime Archaeology Technical Officer Hiro Yoshida assists snorkel diver Madeline Fowler onto the research boat. Sam Wright

Benjamin's students, Chelsea Wiseman and John McCarthy, were the first to find the artifacts.

Diver Chelsea Wiseman investigates the bottom of a submerged freshwater spring off Australia's northwest coast. Hiro Yoshida

The tools weren't easy to find. "Silt turns everything same color," Benjamin said, adding, "you're just looking for shapes in the sea bed and suddenly see lithic tools pop out at you."

A diver searches the seabed for artifacts in the Cape Bruguieres Channel. Hiro Yoshida

The tools weren't easy to find. "Silt turns everything same color," Benjamin said, adding, "you're just looking for shapes in the sea bed and suddenly see lithic tools pop out at you."

The team found tools for cutting and chopping as well as stones for grinding seeds.

A sample of stone tools collected from Australia's Cape Bruguieres Channel. Jonathan Benjamin et al./PLOS One

At a second, nearby site called Flying Foam Passage, the divers found a freshwater spring 46 feet below sea level. In it, they found a stone tool that's at least 8,500 years old.

Snorkel divers examine the seabed in shallow water at Cape Bruguieres. Jerem Leach

At a second, nearby site called Flying Foam Passage, the divers found a freshwater spring 46 feet below sea level. In it, they found a stone tool that's at least 8,500 years old.

The divers photographed and marked the location of every artifact they found but only brought a small sampling of the tools back to the surface.

Archaeologists Jonathan Benjamin and Chelsea Wiseman study geological samples taken from the seabed during their diving fieldwork. Sam Wright

Benjamin said he was surprised at how sheltered the waters of the Diamper Archipelago were: Although a major hurricane hit the area in 2019, the artifacts didn't move.

Jonathan Benjamin assesses a stone tool recovered from Cape Bruguieres Channel. Sam Wright

This discovery gives researchers new information about what life was like for the Aboriginal people occupying Australia before the seas rose. The findings affirm that these ancient people flocked to the coast for food and resources.

Hiro Yoshida fills scuba tanks after a day of underwater survey work. Sam Wright

This discovery gives researchers new information about what life was like for the Aboriginal people occupying Australia before the seas rose. The findings affirm that these ancient people flocked to the coast for food and resources.

This wasn't the first underwater archaeology in Australia: Divers and historians have uncovered multiple shipwrecks from the last century. But Benjamin sees his team's finding as unprecedented.

The Cape Bruguieres Channel and surrounding landscape of Murujuga. Jerem Leach

This wasn't the first underwater archaeology in Australia: Divers and historians have uncovered multiple shipwrecks from the last century. But Benjamin sees his team's finding as unprecedented.

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Divers found a treasure trove of Aboriginal tools on a lost chunk of the Australian continent, which sunk underwater thousands of years ago

Before the seas rose, Australia's coastline extended 100 miles further than it does today. So it's likely many ancient Aboriginal sites are underwater.

Finding those submerged sites can be challenging. It took Benjamin's team three years to pinpoint the two underwater areas where they recently found the trove of tools.

Finally, the team sent divers down to investigate an area known as the Cape Bruguieres Channel in 2019.

Benjamin's students, Chelsea Wiseman and John McCarthy, were the first to find the artifacts.

The tools weren't easy to find. "Silt turns everything same color," Benjamin said, adding, "you're just looking for shapes in the sea bed and suddenly see lithic tools pop out at you."

The team found tools for cutting and chopping as well as stones for grinding seeds.

At a second, nearby site called Flying Foam Passage, the divers found a freshwater spring 46 feet below sea level. In it, they found a stone tool that's at least 8,500 years old.

The divers photographed and marked the location of every artifact they found but only brought a small sampling of the tools back to the surface.

Benjamin said he was surprised at how sheltered the waters of the Diamper Archipelago were: Although a major hurricane hit the area in 2019, the artifacts didn't move.

This discovery gives researchers new information about what life was like for the Aboriginal people occupying Australia before the seas rose. The findings affirm that these ancient people flocked to the coast for food and resources.

This wasn't the first underwater archaeology in Australia: Divers and historians have uncovered multiple shipwrecks from the last century. But Benjamin sees his team's finding as unprecedented.