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Abstract: Sampling issues represent a persistent problem in shell matrix research, particularly for large shell deposits. When small samples are taken from large buried deposits it is almost impossible, under current research practices, to understand how representative that sample is of the overall deposit. This case study tests a novel method for creating a better understanding of the buried deposits from which excavated samples are taken, thereby allowing for improved sampling strategies and a better understanding of how representative those samples are of the overall site. The case study employs two geophysical survey methods, ground‐penetrating radar (GPR) and electrical resistivity, to investigate buried shell deposits under experimental conditions. The survey results were used to create volume estimations and three‐dimensional (3D) models of buried shell deposits. This method is novel to shell matrix research and the current case study was designed to test the viability of the method under differing conditions. As well as testing the two geophysical methods, surveys were conducted under different moisture levels, soil types and survey transect spacings. Results showed that the 3D models and volume estimates of the deposit were successful in creating a representative understanding of the nature of the buried deposit, but with varying degrees of accuracy. GPR results created more accurate volume estimates and 3D models than the electrical resistivity results. Both geophysical methods produced more accurate results under drier conditions, though the electrical resistivity produced more visually distinct results with higher moisture levels. Analysis of the volume results revealed an error margin (to a confidence level of 95%) of 9.5% ± 15.5% for the GPR, and 44.5% ± 31.5% to 56 ± 70.5% for the electrical resistivity, depending on the interpretation method used to create the models. [ABSTRACT FROM AUTHOR]

In regions that lack built structures or stratified open archaeological sites, such as precolonial Australia, rockshelters are a major source of detailed information for understanding the nature and timing of human occupation. A key concern is that the proposed ages for the earliest archaeological sites are based on luminescence dating of sediments, rather than directly of cultural materials, leaving the association between the sediments and evidence of human activity questionable. Here, we present evidence of magnetic enhancement associated with cultural horizons within the deposits of a Pleistocene rockshelter in interior northern Queensland. Soil magnetic studies combined with experimental burning show that magnetically enhanced sediments in Gledswood Shelter 1 are the result of anthropogenic burning of hearth fires, which burn hotter and for a longer time than natural wild fires. These techniques appear to work in this setting because of the nature of the local geology and the geological antiquity of the landscape. Susceptibility and frequency dependence of susceptibility signatures provide a critical tool to resolve that human occupation starts at 2.2 m depth within a stratigraphic section. In conjunction with luminescence dating, soil magnetic studies provide an opportunity for archaeologists to resolve the timing of human settlement in Australia and other intracratonic plate settings. [ABSTRACT FROM AUTHOR]

A GPR survey was carried out in advance of archaeological excavations at Madjedbebe (formerly known as Malakunanja II), a sandstone rock shelter in western Arnhem Land ( Australia) containing numerous Aboriginal burials. GPR revealed subsurface patterning of rocks in the shelter deposits and archaeological excavation demonstrated that these were related to burials. Post-excavation, GIS and statistical analysis further elucidated the relationship between the rocks and human burials. This integration of detailed mapping, GPR and excavation afforded the opportunity to test a way to identify unmarked burials using GPR in sandstone rock shelters and to document a marker for burial identification in this region. Application of the methodology developed through this case study provides a useful management tool for Indigenous communities and other heritage practitioners. [ABSTRACT FROM AUTHOR]