Understanding Australia’s cultural history through archaeological geophysics

Abstract

The aim of this thesis is to develop and apply geophysical methods for Australian archaeology. The methods focus on magnetic susceptibility and ground-penetrating radar (GPR). The techniques are contextualised through application to the following four key archaeological questions: 1) Can magnetic susceptibility assist in resolving questions surrounding the potential downward movement of stone artefacts in rockshelter deposits? 2) Is human occupation persistent through the changing climatic regime associated with the last glacial maximum (LGM) at a Pleistocene-aged rockshelter in interior Australia? 3) How might we identify burials in a geologically complex rockshelter deposit? 4) How might magnetic susceptibility contribute to knowledge about the formation of 'archaeologically instantaneous' shell matrix sites?In exploring these questions, research was conducted at two rockshelters in northern Australia and on three shell mounds in the Gulf of Carpentaria, Australia. Magnetic susceptibility studies were undertaken at Gledswood Shelter 1 (GS1), a rockshelter occupied at ca 38,000 BP, to understand its history and formation processes. An experimental burning program using off-site samples was conducted to confirm that magnetically enhanced sediments in the cultural deposits were the direct result of anthropogenic burning rather than natural fires, pedogenesis or weathering. This change coincides with the level at which stone artefacts appear in the sedimentary sequence, indicating that they are in situ and have not moved down from higher layers above. Demonstrating that an increase in magnetic susceptibility is associated with human occupation is a crucial development in Australian archaeology. This will provide an opportunity to link sediments and artefacts-and this is critical to comprehending the timing of initial occupation of the continent.Magnetic susceptibility data combined with micromorphology and geoarchaeological data also revealed that occupation was continuous through the LGM at GS1, without any abandonment of the site. GS1 is situated in a region that has been characterised as a potential corridor for early colonists moving into the arid interior. The appearance of stone artefacts in the deposits corresponding with an increase in magnetic susceptibility as well as clay and charcoal coatings on quartz grains in the Pleistocene units in thin section, indicate that the site was occupied through this period, thereby implying that water was at least locally available.Despite the absence of any obvious permanent water sources, water availability at the site is ii reliant on summer rainfall. This suggests that the monsoons driven by the Coral Sea off the northeast Australian coastline may have been active during this time. This has important implications for understanding climatic conditions during that period, and allows one to infer that water must have been available regionally for people to have maintained their use of the site.GPR carried out in advance of archaeological excavations at Madjedbe...

When the Foreign Becomes Familiar: The Glass Bead Assemblage from Madjedbebe, Northern Australia

“…These most recent studies revealed a stone assemblage including late Pleistocene-aged grindstones, ground edge axes and ground ochres (Clarkson et al 2017). Subsequent detailed studies have included the analyses of the mid-Holocene shell midden layer (Woo 2020), magnetic susceptibility of the sediments (Lowe 2014), burial patterns (Lowe et al 2014), the archaeobotanics (Carah 2017;Florin et al 2022), Holocene-aged ochres (Cox 2013;Crough-Heaton 2021), flaked stone artefacts (McNeil 2016), ground stone assemblage (Hayes 2015) and bone points (Basiaco 2018;Langley et al 2023).…”

Codesigned Archaeological Research in the Alligator Rivers Region, Northern Territory, Australia

“…Following debate (e.g., Bowdler 2017;Clarkson et al 2018;Smith et al 2020;Veth 2017;Williams et al 2021;Wood 2017), public discourse in Australia has strongly adopted the findings from Madjedbebe, and the 65,000-year date is now routinely cited as the basis for the world's "longest continuous culture" in parliamentary documents, policy documents, government statements, and across the media. A multitude of specialist studies were forthcoming from this project-although, under current arrangements, researchers now seek direct approval from GAC to work on materials excavated from Madjedbebe (e.g., Crough-Heaton 2021; Langley 2021; Langley et al 2023;Litster 2022; and see the case study below), rather than obtaining access via the lead researcher, as was formerly the case (Basiaco 2018;Carah 2017;Cox 2013;Florin 2013Florin , 2020Florin et al 2020Florin et al , 2021Hayes 2015;Hayes et al 2021Hayes et al , 2022Lowe 2014;Marwick et al 2017;McNeil 2016;Moody 2016;Woo 2020).…”

“…Archaeological Research in the Alligator Rivers Region, Northern Territory, Australia August 2023 | Advances in Archaeological Practice | A Journal of the Society for American Archaeology study below), rather than obtaining access via the lead researcher, as was formerly the case(Basiaco 2018;Carah 2017;Cox 2013;Florin 2013Florin , 2020Florin et al 2020Florin et al , 2021Hayes 2015;Hayes et al 2021 Hayes et al , 2022Lowe 2014;Marwick et al 2017;McNeil 2016;Moody 2016;Woo 2020).…”

Archaeology of rock art at Dalakngalarr 1, centralwestern Arnhem Land

“…Due to their strong association with anthropogenic fires, magnetic signals have the potential to be used as a proxy for mapping the spatial and temporal distribution of human occupation (e.g. Herries and Fisher 2010) through both field (Dalan 2007) and laboratory (Dalan and Banerjee 1998) studies.These techniques, particularly the analysis of the magnetic properties of sediments from excavations, have often been applied to rockshelter investigations, including occasionally in Australia (Lowe 2014;Marwick 2005). Far less common is the use of field magnetometry as a tool to investigate patterns of occupation in caves and rockshelters, although such methods have significant potential to map the spatial patterning of occupation within a site.…”