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Aboriginal artefacts on the continental shelf reveal ancient drowned cultural landscapes in northwest Australia

The DHSC project team has published a new open access article in the international journal PLOS ONE: ‘Aboriginal artefacts on the continental shelf reveal ancient drowned cultural landscapes in northwest Australia’

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.

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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.

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Link to the full article published in the Public Libarary of Science (PLOS ONE):

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0233912 

In a first discovery of its kind, researchers have uncovered an ancient Aboriginal archaeological site preserved on the seabed

(Photo: Sam Wright)

For most of the human history of Australia, sea levels were much lower than they are today, and there was extra dry land where people lived.

Archaeologists could only speculate about how people used those now-submerged lands, and whether any traces remain today.

In a study published in PLOS ONE, we report the first submerged ancient Aboriginal archaeological sites found on the seabed, in waters off Western Australia.

The great flood

When people first arrived in Australia as early as 65,000 years ago, sea levels were around 80m lower than today.

Sea levels fluctuated but continued to fall as the global climate cooled. As the world plunged into the last ice age, which peaked around 20,000 years ago, sea levels dropped to 130m lower than they are now.

Between 18,000 and 8,000 years ago the world warmed up. Melting ice sheets caused sea levels to rise. Tasmania was cut off from the mainland around 11,000 years ago. New Guinea separated from Australia around 8,000 years ago.

The sea-level rise flooded 2.12 million square kilometres of land on the continental shelf surrounding Australia. Thousands of generations of people would have lived out their lives on these landscapes now under water.

These ancient cultural landscapes do not end at the waterline – they continue into the blue, onto what was once dry land. 

Landscapes under water

For the past four years a team of archaeologists, rock art specialists, geomorphologists, geologists, specialist pilots and scientific divers on the Australian Research Council-funded Deep History of Sea Country Project have collaborated with the Murujuga Aboriginal Corporation to find and record submerged archaeological sites off the Pilbara coast in WA.

Location of the finds in northwest Australia (left) and the Dampier Archipelago (right). Copernicus Sentinel Data and Geoscience Australia

We studied navigation charts, geological maps and archaeological sites located on the land to narrow down prospective areas before surveying the seabed using laser scanners mounted on small planes and high-resolution sonar towed behind boats.

In the final phase of the research, our team of scientific divers carried out underwater archaeological surveys to physically examine, record and sample the seabed.

Archaeologists working in the shallow waters off Western Australia. Future generations of archaeologists must be willing to get wet! 

We discovered two underwater archaeological sites in the Dampier Archipelago.

The first, at Cape Bruguieres, comprises hundreds of stone artefacts – including mullers and grinding stones – on the seabed at depths down to 2.4m.

A selection of stone artefacts found on the seabed during fieldwork.  

At the second site, in Flying Foam Passage, we discovered traces of human activity associated with a submerged freshwater spring, 14m below sea level, including at least one confirmed stone cutting tool made out of locally sourced material.

Environmental data and radiocarbon dates show these sites must have been older than 7,000 years when they were submerged by rising seas.

Our study shows archaeological sites exist on the seabed in Australia with items belonging to ancient peoples undisturbed for thousands of years.

In Murujuga (also known as the Burrup Peninsula) this adds substantially to the evidence we already have of human activity and rock art production in this important National Heritage Listed place.

A submerged stone tool associated with a freshwater spring now 14m under water.

Underwater archaeology matters

The submerged stone tools discovered at Murujuga make us rethink what we know about the past.

Our knowledge of ancient times in Australia comes from archaeological sites on land and from Indigenous oral histories. But the first people to come to Australian shores were coastal people who voyaged in boats across the islands of eastern Indonesia.

The early peopling of Australia took place on land that is now under water. To fully understand key questions in human history, as ancient as they are, researchers must turn to both archaeology and marine science.

Archaeologist Chelsea Wiseman records a stone artefact covered in marine growth. (Photo: Sam Wright)

Protecting a priceless submerged heritage

Submerged archaeological sites are in danger of destruction by erosion and from development activities, such as oil and gas installations, pipelines, port developments, dredging, spoil dumping and industrialised fishing.

Protection of underwater cultural sites more than 100 years old is enshrined by the UNESCO Convention on the Protection of the Underwater Cultural Heritage (2001), adopted as law by more than 60 countries but not ratified by Australia.

In Australia, the federal laws that protect underwater cultural heritage in Commonwealth waters have been modernised recently with the Historic Shipwrecks Act (1976) reviewed and re-badged as Australia’s Underwater Cultural Heritage Act (2018), which came into effect in July 2019.

This new Act fails to automatically protect all types of sites and it privileges protection of non-Indigenous submerged heritage. For example, all shipwrecks older than 75 years and sunken aircraft found in Australia’s Commonwealth waters are given automatic protection.

Other types of site, regardless of age and including Aboriginal and Torres Strait Islander sites, can be protected but only with ministerial approval.

There is scope for states and territories to protect submerged Indigenous heritage based on existing laws, but regulators have conventionally only managed the underwater heritage of more recent historical periods.

With our find confirming ancient Indigenous sites can be preserved under water, we need policy makers to reconsider approaches to protecting underwater cultural heritage in Australia.

We are confident many other submerged sites will be found in the years to come. These will challenge our current understandings and lead to a more complete account of our human past, so they need our protection now.The Conversation

Deep History of Sea Country: Investigating the seabed in Western Australia.

Jonathan Benjamin, Associate Professor in Maritime Archaeology, Flinders University and ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders University; Geoff Bailey, Emeritus Professor of Archaeology, University of York; Jo McDonald, Director, Centre for Rock Art Research + Management, University of Western Australia; Michael O’Leary, Senior Lecturer in Climate Geoscience, University of Western Australia, and Sean Ulm, Deputy Director, ARC Centre of Excellence for Australian Biodiversity and Heritage, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Exploring Sea Country through high-resolution 3D seismic imaging of Australia’s NW shelf

https://www.sciencedirect.com/science/article/abs/pii/S0277379120303152

DHSC CI Mick O’Leary et al have published a new article in Quaternary Science Reviews.

Almost 2 million square km of Australia’s continental shelf was flooded following the termination of the last glacial maximum, and with it the cultural heritage of the first arrival and coastal occupation of Australia beginning some 65,000 years ago. In order to prospect for this missing cultural record, we must first identify submerged coastal landscapes and landforms that likely provided favourable environments for occupation and resource use. However, this task is challenged by the sheer size of the Australian continental margin. To help address this, we use industry 3D seismic datasets, that cover vast areas of Australia’s continental shelf, to map seafloor bathymetry at high resolution (10e25 m). Our study focuses an area of 6500 square km on the mid/outer shelf regions proximal to Barrow Island. The 3D seismic bathymetry revealed a highly complex and geomorphically mature coastal landscape preserved at depths of 70e75 m below sea level, including coastal barrier dunes, lagoonal systems, tidal flats and estuarine channels. Based on the depth of the submerged shorelines and reconstructed sea level curves, the age range of these coastal landforms is constrained to Marine Isotope Stage 3 (57e29 ka), which overlaps with the known onset of occupation at Barrow Island and the wider Carnarvon bioregion and the adjacent Pilbara. Such feature preservation has significant geoheritage value, but also allows for human behavioural ecology modelling and provides targets for future dating and site survey.

DHSC Project Team: Chief Investigators Jonathan Benjamin and Mick O’Leary

This is part of an on-going series featuring the DHSC project team. This post features Dr Jonathan Benjamin, Associate Professor in Maritime Archaeology at Flinders University and Dr Mick O’Leary, Senior Lecturer in Marine Geosciences as the University of Western Australia. The two have been collaborating since 2016 and have spent the past three years with the DHSC team investigating the seabed in Murujuga (Dampier Archipelago).

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Dr Jonathan Benjamin during DHSC fieldwork (photo: S. Wright)

I learned to dive in 2003 just before moving to Scotland where I undertook my Ph.D. in Archaeology at the University of Edinburgh. Before that, I had spent my undergraduate years studying four-field anthropology, with a focus on palaeoanthropology and archaeology, first at Boston University before completing my BA at UCLA. I loved archaeological fieldwork, language and travel, and so I minored in French and went on to study European prehistory at Edinburgh. There, I combined my interest in archaeology with underwater field methods, first in the cold waters of Scotland’s inland lochs, before shifting to the Mediterranean and warmer, saltier water. I wrote my Ph.D. on the Northern Adriatic, asking: where were the Neolithic and Mesolithic coastal sites in the region? I stayed focused on European prehistory for some time, before turning to the wider issues of coastal and underwater archaeology as a specialisation, working on sites and material culture from all chronological periods. That experience led to my appointment at Flinders University in 2014 when I took up a lectureship in the maritime archaeology program in Adelaide, South Australia, which I now call home (I am proudly a dual citizen). The role as Lead CI on the DSHC project has been a steep learning curve for me, working on a complex project with a large team and my first real experience in Australian archaeology and coastal geomorphology. I had my first cultural awareness inductions with the Traditional Owners and attended my first Council of Elders meetings as a guest of the Murujuga Aboriginal Corporation, who formally authorised their approval our project. Working in unfamiliar territory has been a challenge, but also an incredible opportunity to learn about landscapes and people, past and present.

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Dr Benjamin coordinating the team of scientific divers during DHSC fieldwork (photo: S. Wright)

The DHSC project is an international project with two case study areas. We’ve incorporated method and theory from both Australian archaeology and from Europe, where submerged landscape studies has matured into a bona fide sub-discipline of archaeology and marine geosciences, with considerable contributions from the SPLASHCOS Network and my mentor and DHSC Senior Scholar Prof Geoff Bailey. The landscapes where we have worked during DHSC, in Denmark and northwest Australia, could not be more contrasting. Yet the archaeology, and the ways we study past cultures, has made for some remarkable and though-provoking comparisons. Worldwide, ancient coasts and their human inhabitants were significantly impacted by rising sea levels during the last glacial period, and subsequent warming into the early Holocene. By working with local specialists and studying the evolving coasts we can consider the impacts of marine transgression on past peoples and the archaeological sites they left behind thousands of years ago.

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The Australian sun is no joke! (photo: S. Wright)

Suffice it to say, that the move from Northern Europe to work in the heat of north-western Australia took some acclimation! Fieldwork in Australia is very different, but it is also incredible. The country is magnificent, and its archaeology is ancient and beautiful. Diving in a region that is warm and plentiful in marine life has been a pleasure, though we have had to take a few extra precautions due to the size of some of the local fish! Fortunately for us, they are well fed and shy. Despite these beautiful distractions, and the ever-present need to consider health and safety of our team during all our operations, our scientific diving has remained firmly focused on the search for submerged cultural heritage and drowned archaeology.

Day_6__08840.jpgDr Jonathan Benjamin and Dr Maddy Fowler investigate the intertidal zone during DHSC fieldwork (photo: S. Wright)

Amongst the most rewarding aspects of the DHSC project has been working with our team, in particular Mick O’Leary who has taught me an incredible amount about geomorphology, both generally and as a regional expert on the northwest shelf. ‘I will never again go into the field without a geomorphologist!’ I remember saying during one of our field campaigns that we have co-directed over the past several years in Murujuga (Dampier Archipelago). Indeed, a good geomorphologist is worth their weight in gold! It is especially great to be able to stand on the bow of a boat and discuss physical landscape evolution, and review how and where underwater archaeological site preservation is most likely to occur. For an archaeologist working on submerged landscapes, this is priceless and has led to a great collaboration and joint supervision of talented emerging scholars in submerged landscape studies.Day_6__09747.jpgDr Jonathan Benjamin during DHSC fieldwork (photo: S. Wright)

It is also a big job to undertake a major scientific diving operation as part of a research project like this one. Seeing our research students and early career colleagues, who represent the next generation in archaeology, emerging into specialists in their own right has been incredibly fulfilling, and fun! I am fortunate to have had a great team of colleagues and students to work with during the DHSC project. Working on these ancient submerged landscapes in collaboration with the local TOs and with a team of such enthusiastic researchers and emerging scholars has been an honour.

Day_5__08020.jpgDive tanks must be filled at the end of each day (photo: S. Wright)

Dr Mick O’Leary (University of Western Australia)
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Dr Mick O’Leary getting wet during DHSC fieldwork 

As a marine geoscientist with research expertise in the fields of tropical coastal geomorphology, coral reef and reef-island evolution, and climate change I have been in charge of the geo-scientific and landscape evolution elements of the DHSC project. I studied at JCU, earning a BSc (Hons) and PhD in 2007 before being awarded a three year Leverhulme Trust Post Doctoral Fellowship at Manchester Metropolitan University in the UK. I went on to undertake on a Research Fellowship at Boston University (USA) before going on to work at Curtin University and now UWA. I have held a leadership role as CI on the DHSC Project since its inception and worked alongside my archaeological colleagues to help understand the region, its natural and cultural histories.

My main research focus is on ancient sea-level reconstructions during periods of known climate instability. And although I mostly focus on past sea levels, the data we collect can also be used to inform, future sea-level rise and their impacts.

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Dr Mick O’Leary recording an intertidal feature during DHSC fieldwork

Working on the DHSC and its research objectives since the beginning has required a multidisciplinary, synergistic approach to fieldwork and project planning. We have applied traditional elements of geomorphology, sedimentology and palaeoecology, high resolution geochronological methodologies with cultural and archaeological method and theory. In this respect, the DHSC project has been a true geoarchaeological project, with its results reflecting the various disciplines and perspectives represented by this team. We’ve gotten to know a range of people and colleagues and have shared many long days aboard our local charter vessel.

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Dr Mick O’Leary operating the drop-camera during DHSC fieldwork. Mick’s hot tip: never keep your car keys in your shirt pocket while working on a boat!

Fieldwork is fun but exhausting! We are up early, on the boat and going back and forth between islands. The days can be long but are also very rewarding. And discovery of new sites and new ideas never gets old. The DHSC project has been a great opportunity to jump in and get wet, quite literally! And working in Murujuga in consultation with the Traditional Owners has been a privilege. The DHSC project has also opened up a new frontier in archaeology, bridging geo-sciences with maritime archaeology in a way that has never been done before. It is something we can be proud of and will surely look back in future years to come with fondness and respectful appreciation to the team, the TOs and the local community.

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Dr Mick O’Leary, imagining geomorphology as an Olympic sport during DHSC fieldwork