Uncovering Prospective Palaeo-proterozoic Basins In Western Australia In The Search For Distal Footprints Of Large Ore Systems

The Bryah Basin is part of the Capricorn Orogen, a collision zone between the Archaean Pilbara and Yilgarn Cratons in Western Australia. The Basin is host to significant mineralisation, including mesothermal orogenic gold, copper–gold volcanogenic massive sulphides. Among the challenges in the exploration for these mineral systems is the paucity of outcrop and the extent and variability of a complex regolith cover. To better understand this regolith, a regional-scale, fixed-wing time domain AEM survey was undertaken over the Bryah Basin in 2012. The resulting data were inverted using a smooth model layered earth inversion, taking account of system geometry to better resolve regolith variability in the near surface, to define regolith thickness and to understand the geometry of the regolith-basement boundary. The inverted data show the most dominant regolith features are associated with deep sediment filled palaeovalleys. The regional regolith framework determined from this study provides a basis for better understanding and interpreting an extensive regolith geochemical data set with respect to metalloid anomalies that may be linked to buried Cu-Au mineral systems. It also indicates where cover is relatively thin and therefore offers the opportunity to prioritize areas for exploration.