• Aboriginal artefacts discovered off the Plibara coast in WA represent Australia’s oldest known underwater archaeology. (Deep Sea Country )Source: Deep Sea Country
Rising sea levels on the Pilbara coast have kept the first underwater archaeological sites hidden for thousands of years.
Rae Johnston

2 Jul 2020 - 11:58 AM  UPDATED 2 Jul 2020 - 11:58 AM

Artefacts dated to be at least 8,500 years old have been uncovered off the Pilbara coast in Western Australia. Hundreds of stone tools, including grinding stones, were located at two sea country sites in the Dampier Archipelago.

Two million square kilometres of the underwater landscape on this continent was once inhabited land above sea level. This recent re-discovery has renewed calls for stronger legislation to protect and manage underwater heritage in this Tentative National Heritage Listed Place.

The Murujuga Aboriginal Corporation teamed up with a team of archaeologists from Flinders University, The University of Western Australia, James Cook University, Airborne Research Australia and the University of York to locate the artefacts through the Deep History of Sea Country project, and a series of archaeological and geophysical surveys.

The sites at Cape Bruguieres and Flying Foam Passage provided new evidence of ways of life from thousands of years ago when the sea levels were lower, and the seabed was dry land.

At a depth of 2.4 metres below current sea level, 269 artefacts dated to be at least 7,000 years old were found at Cape Bruguieres. An underwater fresh spring at the second site, Flying Foam Passage, is 14 metres below current sea level and dated to be at least 8,500 years old.

The researchers said the dates given are minimum ages, and both sites are likely to be much older.

"This is an exciting step for Australian archaeology as we integrate maritime and Indigenous archaeology and draw connections between land and sea," said Associate Professor Jonathan Benjamin.

The Maritime Archaeology Program Coordinator at Flinders University's College of Humanities, Arts and Social Sciences, Associate Professor Benjamin said a massive amount of archaeological evidence documenting the lives of Aboriginal people is now underwater.

"Australia is a massive continent, but few people realise that more than 30 per cent of its land mass was drowned by sea-level rise after the last ice age."

"Now we finally have the first proof that at least some of this archaeological evidence survived the process of sea-level rise. The ancient coastal archaeology is not lost for good; we just haven't found it yet. These new discoveries are a first step toward exploring the last real frontier of Australian archaeology."

Chelsea Wiseman has been working on the Deep History of Sea Country project as a part of her PhD with Flinders University and said the re-discovery of these sites show that artefacts have survived sea-level rise in shallow water, meaning there are likely to be more in deeper water. 

"At one point there would have been dry land stretching out 160 km from the current shoreline," said Ms Wiseman.

"Managing, investigating and understanding the archaeology of the Australian continental shelf in partnership with Aboriginal and Torres Strait Islander traditional owners and custodians is one of the last frontiers in Australian archaeology," said Associate Professor Benjamin.

"Our results represent the first step in a journey of discovery to explore the potential of archaeology on the continental shelves which can fill a major gap in the human history of the continent."