A pilot study into the geochronological and geomorphic context for the archaeology of Barrow Island, Western Australia

Abstract

The island sanctuary of Barrow Island on the edge of the inner North-West continental shelf of Australia holds significant environmental as well as Indigenous and colonial cultural value. Insights on past occupation dynamics, particularly in response to Post-Glacial sea-level rise, continue to emerge from analysis of archaeological assemblages. However, there is limited temporal and landscape information from the wider island with which to better contextualise the physical site formation history of these cultural records. We present a new, modelled Post-Glacial sea-level curve for the region and new geochronological and sedimentological data (including rare earth element and quartz microtextural data) from non-archaeological site contexts to help infer changes in the coastal environment. This new data provides new insights on the island's paleogeography and evolution since approximately 80 ka BP in the context of inherited Last Interglacial features and highly dynamic oceanographic processes. Ongoing physical weathering processes have influenced dune building and reworking, such that neither colour nor numeric age are reliable indicators of sediment compositional and textural maturity. The results continue to emphasise how the continued integration of the island's geological, sedimentological and archaeological records help to understand aspects of cultural site formation, as well as expose some of the limiting factors in our understanding of past and present island physical dynamics.