Integration of GPR and magnetics to study the interior features and history of earth mounds, Mapoon, Queensland, Australia

Abstract

AbstractThe nature of earth mounds and their function over time in northern Australia is of ongoing academic debate. Here we present how the integration of ground‐penetrating radar (GPR) and magnetic data, after being adjusted for surface elevation changes, was used to analyse the interior features and objects within six earth mounds in Mapoon, western Cape York, Australia. These geophysical techniques were merged and interpreted jointly to produce images of the stratigraphic units and objects within the mounds to determine their extent and composition. It was found that some mounds were built over burned areas that contain large objects on the original ground surface. Those modified areas were then converted into substantial earth mounds, which reach a maximum height of about 4 m. Other mounds nearby show no evidence of pre‐construction burning. In one mound cluster the western three mounds contain human burials that were visualized using GPR profile interpretation. The nearby eastern three mounds were devoid of human burials, but contained many of the pre‐mound burned features seen in those just a few hundred metres to the west. The close proximity of these six mounds, with very different associated features and internal objects suggests that they are related in some way, but differed in their function. It is also possible that they were constructed at different times by different people. The data analysis techniques presented in this article assists with further opportunities to undertake non‐destructive investigations of these earth mounds that are culturally appropriate to living Aboriginal people. They will also help to resolve the function and possible importance of these constructed features over time.