AAA2020 Virtual Conference Banner 7 - 10 Dec

Submerged Landscape Archaeology and the Deep Past of Australia

Chelsea Wiseman
Flinders University

Jonathan Benjamin, Flinders University
Sean Ulm, ARC Centre of Excellence for Australian Biodiversity and Heritage, James Cook University

At the Last Glacial Maximum, global sea level dropped as low as -130 m, adding 2 million square kilometres of land to the continental land mass of Australia. Generations of Indigenous Australians lived in these extensive areas of the now-drowned continental shelves and through dramatic rises and falls in sea levels across the late Pleistocene and Holocene. The potential for archaeological material to be preserved following sea-level rise is now demonstrated by two subtidal archaeological sites in Murujuga (the Dampier Archipelago) dating to at least 7500 BP, in addition to the presence of other sites in Australia, including intertidal material and submerged freshwater sites. These examples indicate the substantial potential to locate and investigate archaeological sites on the continental shelf of Australia, further supported by the thousands of submerged sites identified in the marine environments of Europe, the Middle East, and North America. This session brings together researchers working both in Australia and internationally to discuss the ongoing development of submerged landscape archaeology as a discipline, with an emphasis on its future in Australia. Themes for discussion in this session include inundated sites in Australia and prospective locations for investigation, coastal and intertidal archaeology, the peopling of Sahul, and international case studies of submerged archaeological sites.

Drowned Landscapes of the Continental Shelf: Current State of Play and Future Directions

Geoff Bailey
University of York

In the past decade, underwater archaeological exploration of the continental shelf has gained momentum from new discoveries, new research initiatives, new collaborations, new technologies, involvement of an increasing number of researchers and a growing appreciation of just how large a gap these submerged landscapes represent in our knowledge and understanding of human developments over the past 100,000 years. Most of the new discoveries and initiatives have taken place in the northern hemisphere, especially in Europe and North America, but recent discoveries have now placed the same sort of research firmly on the Australian research agenda. Nevertheless, this research field is still in a pioneer phase, with considerable scepticism and uncertainty about what sort of archaeological remains are preserved after inundation by marine transgression, how to find them, or what difference their discovery and analysis might make to our understanding. Meanwhile, theoretical models persist that, while recognising the existence of millions of square kilometres of drowned territory, continue to assume that it attracted relatively little human settlement. 

In this presentation, I will pick out some of the highlights of recent research and identify key challenges for the future. These challenges include: the development of collaborative research networks on the pattern of the SPLASHCOS and Aquaterra networks of Europe and North America; a better understanding of the taphonomic and depositional history of underwater archaeological remains; a concerted move to explore the deeper parts of the continental shelf; and recognition that success will depend on research initiatives that are not only interdisciplinary, but also genuinely inter-institutional, international, and that also involve collaboration with offshore industries, Traditional Owners and the relevant governmental agencies, and communication with a wider public.

Framing Pleistocene Coastal Occupation in Australia: An Assessment of Archaeological Evidence with a Focus on North-Western Australia

Kane Ditchfield
University of Western Australia

Sean Ulm, ARC Centre of Excellence for Australian Biodiversity and Heritage, James Cook University
Tiina Manne, University of Queensland
Fiona Hook, Archae-aus
Peter Veth, University of Western Australia

Relatively little is known about the occupation of Pleistocene coastal landscapes in Australia. This is largely because there are only a limited number of optimal sampling locations for Pleistocene coastal landscapes, such as coasts adjacent to steep continental shelves, areas of uplift and continental islands. Even where higher landmasses might register Pleistocene occupation, there is vigorous debate about whether these earlier coasts were occupied. One persistent school of thought is that Pleistocene coasts were relatively marginal with fluctuating sea levels actively inhibiting coastal resource productivity and hence occupation. The other scenario is that coasts were always productive for coastal foragers, but sea level rise has drowned most of the evidence. In essence, the arguments are based on both coastal productivity and taphonomy. In this paper we briefly review, update, and assess the published evidence for Pleistocene coastal occupation and productivity in Australia with a focus on recent data from NW Australia. We focus on preservation as well as marine and terrestrial fauna and their relationship to coastal productivity and occupation. We find that there is an increasing body of evidence for Australian coastal productivity and occupation during the Pleistocene and map out future research areas.

Uncovering Submerged Ancient Aboriginal Landscapes in Murujuga, Western Australia

Chelsea Wiseman
Flinders University

Mick O’Leary, University of Western Australia
Jo McDonald, University of Western Australia
John McCarthy, Flinders University
Jorg Hacker, ARA – Airborne Research Australia
Sean Ulm, ARC Centre of Excellence for Australian Biodiversity and Heritage, James Cook University

Jonathan Benjamin, Flinders University

In 2019, the Deep History of Sea Country project located the first two submerged ancient Aboriginal sites off the coast of Western Australia in Murujuga (the Dampier Archipelago). Until this project, no subtidal Indigenous archaeological sites had previously been found on the continental shelf of Australia. This project represents a pioneering and multi-disciplinary approach to the identification of submerged archaeological sites in Australia. The process integrated the use of widely available data including satellite imagery and nautical charts, alongside airborne LiDAR, boat-based marine geophysical survey, and drone survey, with knowledge of regional archaeology and geomorphology, to then evaluate highly prospective areas for diver survey. The outcomes of this project indicate the extensive archaeological potential of submerged landscapes, with significant implications for the ongoing research and management of the underwater heritage of Australia.

ACROSS Submerged Landscapes of Australia’s Deep Past

R. Helen Farr
University of Southampton

Anthony Fogg, University of Southampton
Justin Dix, University of Southampton

The earliest maritime crossings from the Sunda shelf (Island South East Asia) into Sahul (Australia and New Guinea) occurred in deep time, and represent some of the earliest seafaring in human history. One way in which we can better understand this maritime activity is to understand the changing nature of the coastal palaeolandscape within which these crossings took place; to do this we must study the now submerged landscapes of Australia’s deep past.

On the north western Australian shelf, extensive seismic coverage has allowed geomorphological interpretation of an evolving coastal and fluvial landscape. From this it is possible to infer coastal positions and landscapes over the last glacial period denoted by Marine Isotope Stages (MIS) 5e-1.

This paper focuses on an area encompassing the Bonaparte Gulf during MIS 4, where a lowstand relative sea level minimum of approximately 77-80m below present day developed ~63kaBP. This time range is consistent with some of the earliest recorded dates supporting human occupation of northern Australia by 65kaBP.

The interpretation of geomorphological features from the seismic database has allowed prediction of most likely coastal position and possible tidal ranges during the MIS 4 lowstand in addition to contemporaneous depositional environments associated with reef, beach, estuarine, lagoonal and fluvial facies in an emergent landscape. The predicted palaeocoastline models are now being used to run simulations of tidal and ocean currents to inform possible maritime transit routes from Sunda to Sahul.

New Approaches to the Prehistory of the Continental Shelf of the Sunda Area

Nicholas Flemming
National Oceanography Centre, Southampton, UK

The archaeological importance of the increased land area around he Sunda Arc at the LGM was recognised before 1940. Every writer concerned with the prehistoric occupation and fossils of Indonesia and north Australia refers to the increase of land area at the LGM. The vegetation and river drainage pattern, and the distribution of lakes on the submerged shelf have been broadly evaluated in the last two decades. At the present date only one submerged prehistoric site area has been found anywhere in the world between the Tropics: that is the submerged lithics in Murujuga (Dampier Archipelago). Of the thousands of submerged sites known globally, all others are in temperate mid-latitudes. The reasons have still not been determined, and it is important to start from first principles so as to calculate the steps needed to find more submerged sites in tropics and the Sunda Arc. The coastal morphodynamics and biota determine firstly the potential for occupation, and then for the survival of relic deposits. Coral reefs, mangrove forests, deserts, rainfall and runoff patterns create consequences quite different from the mid-latitudes. Analyses of the distribution of AMH and earlier hominins have been described in the context of a larger continuous Sunda land mass, and then the effect of the rising seas breaking that mass into smaller islands. These changes break up previous populations of fauna, and increase the rate of speciation. But the process of studying the sea floor for direct archaeological data has not received funding or the commitment of major institutions. Some publications still state that all anthropogenic signals are destroyed by rising sea level. This paper proposes steps that could be taken to scope out the research stages of discovering submerged sites on the Sunda shelf.

The Tempest: A Geoarchaeological Examination of Post-Depositional Processes Driven by Tropical Cyclone Impacts at a Submerged Shell Midden Site in Florida, U.S.A.

Jessica W. Cook Hale
University of Georgia

Nathan L. Hale, Aucilla Research Institute
Ervan G. Garrison, University of Georgia

We present here results of sedimentological analysis of a submerged shell midden site, the Econfina Channel site (8TA139), in the Gulf of Mexico, Florida, U.S.A. We collected three bulk sediment datasets before and after the passage of two tropical cyclone systems in 2016 and 2017. We used particle size analysis (PSA) to assess the degree to which site sediments were disturbed and to infer what, if any, impacts we could detect associated with these storms. This fills a critical knowledge gap because submerged landscapes experience post-depositional forces during and after submergence unlike those experienced by terrestrial sites, including tropical cyclones. This work also complements efforts along coastlines to mitigate against the accelerating impacts of increasing storm impacts and marine transgression driven by climate change. Our results indicate that tropical cyclone impacts at this submerged site were less erosive than comparable effects recorded at terrestrial sites, at least in this region.

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