Archaeologists in the north-west of Western Australia are conducting a survey with a difference at the bottom of the ocean.
The pioneering project is searching for underwater evidence of ancient Indigenous culture in the Dampier Archipelago.
This morning’s ABC News featured the DHSC project team’s recent fieldwork and diving survey campaign in WA. Keep an eye out for more content to appear on ABC news outlets, including radio, online media and ABC iView.
Part 1: Submerged sites
I joined the Deep History of Sea Country (DHSC) project on fieldwork at the island of Hjarnø, Denmark, in June 2018 as a representative of the Queensland Museum Network and James Cook University, both part of the UNESCO UNITWIN Network for Underwater Archaeology. This project was my first opportunity to engage with the fast-growing field of submerged ‘prehistory’. Since entering the maritime archaeology discipline, there have been no previous opportunities to take part in the study of submerged landscape archaeology in Australia. So, I was very excited to have this opportunity to contribute my scientific diving skills to the project, while also learning a great deal about the Mesolithic archaeology of Denmark.
Besides brushing up on my lithic identification skills, I gained experience in excavating a submerged landscape. The excavation in a shallow intertidal environment was very different to the nineteenth-century shipwrecks I have excavated before in Australia, given the diverse site and artefact types. Yet, excavation methods—that is the methods and techniques of underwater archaeology—are the same. Submerged landscape archaeologists add other methods to their toolkits, such as geophysics and coring. Using many sources is like the varied sources adopted by historical archaeologists, such as archival documents and oral histories. Both interdisciplinary approaches allow a more complete picture of the landscape and the way people interacted with it in the past.
As a theorist, I couldn’t help asking the question: are they both maritime archaeology? A lack of exposure to submerged landscape archaeology throughout my education and training and within Australian maritime archaeology (owing to the drivers that led to its development) have led me to associate maritime archaeology with (Western) seafaring. Of course, maritime archaeology is, at its heart, the study of people, culture and their interactions and relationship with the sea through the material and physical remains left behind, preserved through time as archaeological evidence. The definition of maritime archaeology should encompass the entire range of people’s relationships to the seaboard and other aquatic bodies, and their physical and cultural environments.
The location of the submerged landscape we were excavating at Hjarnø was part of an ancient (palaeo- or perhaps meso-maritime) shore at the time of its creation by people archaeologists call the Ertebølle culture. Yet Ertebølle peoples’ intensive exploitation of marine resources must have led to a thorough knowledge of the underwater landscape at that time, such as the location of oyster and cockle beds. Thus, the submerged landscape in the past, though concealed from the peoples of the past, was an integral part of their cognition. Despite the site’s formation on land—and the lack of archaeological evidence of seafaring or nautical technology—the people were still connected to the maritime sphere. The now inundated sites are landscapes of maritime culture and maritime archaeologists must situate it within their remit.
While Australian archaeologists haven’t discovered submerged sites on the continental shelf, the increasing interest and resources in this field, such as the DHSC, will soon provide opportunities for Australian-based students, and early career researchers like me, to learn these skills at home. While I had the advantage of learning these skills firsthand in Denmark—an ideal global training-ground for submerged ‘prehistory’—I cannot call myself a submerged landscape archaeologist. Well, not yet anyway. What I can do is consider myself to be a better, more well-versed maritime archaeologist!
Part 2: Submerged surveys
Fast-forward a year and I have re-joined the DHSC team in Murujuga (Dampier Archipelago), Western Australia, this time as a volunteer. I also have a my new role as a Senior Research Fellow with the University of Southampton, though I maintain an ongoing affiliation with Flinders University as an Adjunct Associate Lecturer. Unlike the Danish fieldwork, the research in Western Australia is searching for prospective areas of submerged archaeology, rather than excavating known sites.
The DHSC team has already spent some time surveying in Murujuga, integrating several aerial and marine survey datasets to refine the diver-based survey strategy. Remote sensing marine geophysical survey included bathymetric lidar and sidescan sonar investigation, in addition to drone-based aerial imagery. Combined with coastal and intertidal surveys, analysis of this data led to the identification of priority areas for diver survey this September.
Using a survey grid with a 20-metre line-spacing has helped to define the survey in a systematic way and will establish whether or not the areas of interest are productive. Using a 100-metre leaded line, buoyed on both ends, diver buddy pairs surveyed the lines and tracked their location with a GPS attached to a dive flag buoy on the reel. With the cameras and GPS mirroring the time, underwater photographs of potential features of interest could later be positioned with accuracy. This survey approach presents an effective and accurate method for searching for submerged landscapes in Australia’s nearshore continental shelf environments, inundated by past sea-level rise.
Being involved in this intensive search for evidence of submerged landscapes in Australia has reinforced the promise of this study area to not only contribute to our understanding of Aboriginal peoples’ adaptation to changing environments in the past, but also to shifting the biases of Australian maritime archaeology. The next generation of archaeology students will be the first to fully embrace these opportunities, and, as an early career researcher, I may now be well on the way toward a fuller, better appreciation for submerged landscape archaeology as a global discipline and indeed, a progressing discipline in Australian archaeology.
Last year our survey team took to the sea aboard the small work boat DAN K (operated by Aust Marine out of Dampier, WA). The team consisted of DHSC staff and research students, based in Adelaide, Perth and overseas. The purpose of the surveys were to complement the data we gathered through bathymetric lidar with sidescan sonar data and identify priority areas for diver survey. The team continued to update the local community Members via the Murujuga Aboriginal Corporation (MAC), who have been involved and updated of our on-going project since the onset.
Sidescan sonar survey allows us to record significant areas of the seabed and view the submarine environment through high-resolution acoustic images. This is important to locate areas of the Dampier Archipelago where submerged cultural material is likely to have preserved so we could characterise the seabed and see what the bottom is made of and what is sitting on the seabed. This will help our divers to select locations to survey later in the project.
Working at sea
Sidescan data collection can be slow going, and is not without its complexities. We need good sea conditions, good weather and the right wind, and good operators. All of the data has to be logged, organised and eventually processed. We had a few false starts early in the year, with technical issues, power problems, and of course bad weather. It took three tries to get it right. But then it all came together.
Our third attempt was the winner. We had 9 consecutive days of calm, beautiful weather last September/October. In that amount of time we could map as many places as we could possibly get to, working 12 hour days at sea, running survey lines back and forth in neat polygons. Hats off to the full time professional marine surveyors who do this for their living year round. They have a seriously challenging job!
We were lucky to have a couple of project team members with such experience and capacity. Francis Stankiewicz, who has previously posted about the Danish component of the project, and Dr Paul Baggaley (Adjunct Lecturer in Maritime Archaeology at Flinders University, and CTO of Wessex Archaeology in the UK). Thanks to a real combined team effort, a bit of luck with the weather, and our hard working crew, we got the data we needed at the survey sites we wanted.
We have now processed the geophysical data and selected target areas for further investigation. The integration of several remote sensing datasets helps to refine our survey strategy, and better understand the submerged environment of the Dampier Archipelago.