We report Australia’s first confirmed ancient underwater archaeological sites from the continental shelf, located off the Murujuga coastline in north-western Australia. Details on two underwater sites are reported: Cape Bruguieres, comprising > 260 recorded lithic artefacts at depths down to −2.4 m below sea level, and Flying Foam Passage where the find spot is associated with a submerged freshwater spring at −14 m.
The DHSC project team recognises the Murujuga Aboriginal Corporation Council of Elders and Murujuga Land and Sea Rangers Unit as core collaborators on this project.
The DHSC project was supported by the Australian Research Council, Flinders University and the Hackett Foundation. We thank our many colleagues, volunteers, and friends of the project including Ken Mulvaney, Shakti Chakravarty, Victoria Anderson, Sarah de Koning, Hiro Yoshida, Kerry Ludwig, Mads Holst, Sam Wright, Annette George, Tom Allardyce and Graham and Michelle Evans and the AustMarine staff for their support throughout the DHSC project. Further thanks to EGS Surveys and the Pilbara Ports Authority for supplying additional survey data.
Link to the full article published in the Public Libarary of Science (PLOS ONE):
When people arrived in Australia more than 65,000 years ago, they landed on shores that are now deep under water. The first footprints on this continent took place on these now-submerged landscapes.
More than 2 million square kilometres of Australia’s continental landmass — an area larger than Queensland — was drowned by sea-level rise over the last 20,000 years. This land was once home to thousands of generations of Indigenous peoples.
In two new studies published in Australian Archaeology, we outline approaches to help us better understand and manage Indigenous underwater cultural heritage.
Through a two-pronged approach at both the local and regional level, we review big data to predict the location of sites. We also put boots on the ground and divers in the water to find and record them.
At the local level, our research at Murujuga in northwest Australia indicates we must combine archaeological data from above and below the water to understand the past landscape at periods of lower sea level.
Drawing on evidence from across terrestrial, coastal and submerged environments, we found archaeological material in all three zones.
Our study also aligns archaeological practice with histories of Indigenous Australians, who describe cultural landscapes extending into Sea Country. Some oral histories describe past sea-level rise and drowned cultural landscapes.
At the regional scale, our study shows how research into submerged landscapes can be expanded across Australia. Taking the Northern Territory as a case study, we assessed the potential for archaeological material to be preserved on the seabed.
National environmental frameworks, such as Marine bioregional plans for Australia’s seabed focus largely on marine biodiversity and habitats, only acknowledging archaeology through a selection of historic shipwrecks.
With few regional or state-level mechanisms in place to inform marine management planning, Indigenous underwater cultural heritage has been ignored or marginalised. There is now an opportunity and an ethical obligation to integrate Indigenous perspectives and traditional knowledge into marine science research.
Threats to underwater Indigenous heritage
Indigenous underwater cultural heritage is threatened by a variety of activities, including dredging, offshore cables and pipelines, seabed mining, and oil and gas exploration.
Such developments can cause significant damage and even explosions and fires in the sea, as witnessed recently in the Gulf of Mexico.
We can expect increased pressure on coastal and submerged sites with the increasing impacts of climate change. Without mechanisms to consider the archaeology in the intertidal zone of Australia (the transitional area between land and sea) and the seabed, such disturbances will occur out of sight and out of mind.
Some state and local laws protect underwater cultural heritage, but these vary across the country. The national Underwater Cultural Heritage Act also does not adequately protect Indigenous cultural heritage.
Archaeologists working in partnership with Indigenous communities must take a central role in scientific research, management of marine environments and industry-led campaigns, incorporating archaeology into environmental impact assessments.
Industry has begun to respond. One company, Woodside Energy, for example, has acknowledged the importance of this issue, and has engaged with the Murujuga Aboriginal Corporation. The company says it has sought to understand the potential heritage values of the submerged cultural landscape for the proposed Scarborough pipeline.
Coastal peoples all over the world have made a significant contribution to human history. Only through underwater archaeology can we fully understand these past peoples who called coastal environments their home.
by Katherine Woo, James Cook University; Geoff Bailey, University of York; Jessica Cook Hale, University of Georgia; Jonathan Benjamin, Flinders University, Sean Ulm, James Cook University and Peter Moe Astrup, Curator of Maritime Archaeology at Moesgaard Museum.
The world’s oceans hold their secrets close, including clues about how people lived tens of thousands of years ago.
For a large portion of humanity’s existence, sea levels were significantly lower (up to 130 metres) than they are today, exposing millions of square kilometres of land. And the archaeological record is clear: people in the past lived on these coastal plains before the land slipped beneath the waves.
Archaeology already tells us these drowned landscapes played significant roles in human history. Major events such as human migrations across the globe and the invention of maritime technology took place along these now-drowned shorelines.
But these sites can be hard to find.
In twopapers published this week our team reports on a breakthrough in detecting and excavating one particular type of coastal archaeological site — shell middens — on what is now the seabed.
The rich trove of evidence in these middens offer clues on how people adapted during times of sea-level rise and climate change.
It was long thought shell middens would be unlikely to survive the effects of rising sea levels – or if they had, it would be impossible to distinguish them from natural debris on the ocean floor. Our new findings suggest that’s not necessarily the case.
A new way to detect and excavate underwater middens
In recent decades, archaeologist have systematically searched the globe for evidence of these submerged cultural landscapes.
However, rough currents and poor visibility can make it difficult to find and record underwater sites.
In two journal articles published this week, our team has announced new ways of detecting and excavating shell middens from what is now the seabed.
Previously, shell middens were hard to differentiate from natural shell deposits.
But our examination of three shell middens between 7,300 and 4,500 years old – from the Gulf of Mexico, the United States and Eastern Jutland in Denmark – demonstrate how submerged middens not only survive, but retain a distinct “signature” which can be used to separate them from naturally accumulated debris on the sea floor.
By using microscopy, geological and geophysical techniques, 3D reconstructions, and biological and ecological studies, we teased out different strands of evidence that offer new insights into how we might find other midden sites in watery depths around the globe.
Challenging what we thought we knew about ancient coastal communities
What we’ve found so far challenges current ideas about coastal use in the Gulf of Mexico and northern Europe.
In the Gulf of Mexico, there is a gap in midden sites from between 5,000 and 4,500 years ago along the coastline of our study area. New results suggest localised sea-level changes, not lack of occupation, explain that gap.
In Denmark, the discovery of these middens (which are rare in the south) hints this type of site was more common than previously thought. That shifts our understandings of how intensive coastal use may have been between 7,300 and 5,000 years ago.
Importantly, bothstudies imply our histories of past coastal use may need to be rewritten as more such sites are found. Previously, many archaeologists assumed that people only occupied stable coastal zones. However, in both of our study areas, this was not the case.
Furthermore, older examples of similar middens likely lie offshore in multiple regions. Our new methods can make the search for such sites easier and more efficient.
Clues about adapting to a changing environment
Research at these sites is generating critical information that is beginning to fill in missing pieces of the puzzle of the human past.
Shell middens are complex, culturally significant sites. Some are the result of people discarding food refuse, tools, and other remnants of daily life. In other cases middens are purposefully built for cultural reasons, including burials. Often they are a mix of both.
They thus provide fundamental information about past food choices, tool technology, trade practices, and cultural values. These different types of information allow us to infer how people adapted their cultures over time. They also hint at how people interacted with their surrounding environments even as sea levels rose and the climate changed.
Understanding the past can help us contend with the future
These findings are not just important for our understandings of the past. They have direct and significant impacts on modern people, especially the rights of Indigenous and First Nations people across the globe.
These Nations have long impressed on us their deep connections with marine environments and seascapes. However, recognition of these relationships in western environmental and heritage conservation policies has been slow and deeply inadequate.
These new findings support Indigenous and First Nations people to manage the cultural heritage of their ancestral lands and waters by documenting these relationships into the deep past.
The discovery of these underwater sites, and the promise of more to be found, means industry, developers, archaeologists, and government bodies must reassess how we manage and protect ancient Indigenous heritage in these underwater settings. That is especially true as offshore mining and development accelerates.
Second, the UCH Act offers two tiers of site protection: UCH that is automatically protected, and UCH that may be declared to be protected with ministerial approval.
So what is automatically protected by the UCH Act (2018) ? Here it is:
All vessels that have been in Australian (ie. Coastal or Commonwealth) waters for 75 years or more are automatically protected by the Act. A 75 year old sunken shipwreck whether it is found near the beach, or offshore on Australia’s continental shelf, is protected automatically by the UCH Act. Sunken aircraft located in Commonwealth waters are also protected automatically by the Act.
Heritage located under water within 0-3 nm Coastal waters zone, may also be protected by the policies of each individual State or the NT, and the details of protection vary in each State or Territory.
Indigenous archaeological sites discovered on the seabed, whether in Coastal or Commonwealth waters are not automatically protected in the same way that historic shipwrecks are protected by the UCH Act (2018).
Protection of Indigenous sites in Coastal waters would therefore defer fist to the individual State’s heritage laws to protect a site located in the 0-3 nm Coastal waters zone. The Federal UCH Act could potentially protect Indigenous sites in Australian waters (Coastal or Commonwealth waters), but only ‘if the Minister is satisfied that the article is of heritage significance’. This has yet to be tested.
Australia’s UCH Act (2018) diverges from the UNESCO Convention on the protection of Underwater Cultural Heritage (2001) which is widely referred to as global Best Practice. The UNESCO (2001) Convention defines Underwater Cultural Heritage as ‘all traces of human existence having a cultural, historical or archaeological character which have been partially or totally under water, periodically or continuously, for at least 100 years …’
There are different mechanisms to protect Indigenous heritage under water and the individual state heritage laws serve as the primary mechanism that would be protect Indigenous UCH in Coastal waters. Any Indigenous sites found in Commonwealth waters could be protected, but only with ministerial approval.
However, the Australian federal law that “provides for the protection of Australia’s underwater cultural heritage” does not automatically protect Indigenous UCH in Australian waters.
That is, unless… Indigenous material culture was present onboard a historic vessel when it sank. Then the Indigenous artefacts would be automatically protected… because of their association with the historic shipwreck.
During the past 20,000 years approximately one-quarter of the continental landmass of Australia was inundated by postglacial sea-level rise, submerging archaeological evidence for use of these landscapes. Underwater archaeological sites can offer substantial insights into past lifeways and adaptations to rapidly changing environments, however the vast scale of inundation presents a range of challenges in discovering such sites. Here we present a suite of methods as a model methodology for locating sites in submerged landscapes. Priority areas for survey were based on palaeoenvironmental contexts determined from the onshore archaeological record. Remote sensing was used to identify seabed composition and indicators of palaeolandscapes where high potential for human occupation and site preservation could be identified in Murujuga (or the Dampier Archipelago), northwestern Australia. Target locations were surveyed by scientific divers to test for the presence of archaeological material. Application of this methodology resulted in the discovery of the first two confirmed sub-tidal ancient Aboriginal archaeological sites on Australia’s continental shelf. Survey methods are discussed for their combined value to identify different classes of landscapes and archaeological features to support future underwater site prospection.