Author: Peter J Ross
Ross, Peter J, 2021 Archaeological preservation and feature identification in subaerial and submerged environments, Dampier Archipelago, WA, Flinders University, College of Humanities, Arts and Social Sciences
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The earliest human migrations and settlement occurred in Australia when sea-levels were significantly lower than contemporary levels. The Dampier Archipelago, located off Western Australia’s Pilbara coast, contains some of the highest concentrations of archaeological sites in Australia, suggesting offshore archaeological materials may also be present. Research conducted for this thesis aims to assess the capacity of archaeological deposits and material culture in submerged environments to resist the potentially destructive or disturbing effects of meteorological and oceanic processes. This is accomplished by considering coastal phenomena affecting preservation as it relates to inundated archaeological materials, with a special consideration of tropical cyclones as recurring storm systems that affect the environment and the preservation and visibility of submerged archaeological materials. In addition to this process-based approach, site specific searches for submerged archaeological materials were conducted using airborne lidar-derived representations of registered archaeological features on land as analogies to aid the search for similar features in submerged coastal environments.
The Pilbara region experiences the highest rate of landfalling tropical cyclones in Australia, and their impact likely affected archaeological preservation in the Dampier Archipelago. Change detection analyses of satellite imagery conducted for this thesis successfully quantified environmental changes attributable to tropical cyclone impact and the preservation of archaeological materials, but those thresholds were locally variable owing to the heterogeneity of natural environments. Cyclone-prone and weathering-limited regions such as the Dampier Archipelago exhibit low levels of observable environmental change even after severe cyclones, but undoubtedly experienced significant environmental changes in the past. The limited weathering of the predominantly igneous rock landforms suggests little, or no preservative sediments were available to rebuild coastal landforms or rebury and preserve archaeological materials exposed by cyclone activity, making them even more susceptible to degradation from subsequent tropical cyclone impacts.
Airborne lidar confidently identified large archaeological features on land such as shell mound middens and fish traps. However, the significant depths of mobile seabed sediments in offshore areas masked the underlying landscape and possibly archaeological features from the lidar sensor, suggesting that lidar was not the best remote sensing choice for the purposes of identifying inundated archaeological sites or features under such conditions. Airborne lidar prospection combined with an informed consideration of meteorological and oceanic processes enabled the identification of new sites on land (shell mounds), the definition of new target areas for future underwater site prospection, and a basis for the critical evaluation of the status of existing and future discoveries of underwater archaeological finds.
Keywords: Dampier Archipelago, Pilbara, archaeology, preservation, submerged, marine, cyclone, satellite, lidar
Subject: Archaeology thesis
Thesis type: Doctor of Philosophy
Completed: 2021
School: College of Humanities, Arts and Social Sciences
Supervisor: Jonathan Benjamin