Regional gravity and regolith geochemistry as an integrated tool for mineral exploration

Abstract

The Geological Survey of Western Australia has carried out helicopter-supported regional regolith sampling and gravity capture, based on a 4×4 km sampling grid. Started initially as a regolith-sampling program in 1994, gravity capture was added in 1998 with little increase in cost or time. Each survey targets a 1:250 000 scale map sheet in less extensively explored parts of Western Australia, which invariably have poor gravity coverage. The gravity data provide valuable information on regional-scale structures and help in the interpretation of regolith chemistry. In conjunction with regional aeromagnetic surveys, the gravity data are also of use in regional mapping. In an area of Proterozoic and Archaean rocks in central Western Australia, areas of potential mineralization have been identified by combining gravity data with regolith chemistry and bedrock mapping to indicate where regional faults and shear zones have probably acted as conduits for mineralizing fluids. The simultaneous capture of gravity data and regolith samples in the same field program is an effective approach to regional mineral exploration.