Detailed Ground Radiometric and Magnetic Surveys of the Leviathan and South Venus Gold Prospects, Western Australia

In Western Australia, exploration for low-grade gold mineralisation is hindered by the presence of a deep mantle of weathering. Application of geophysical techniques at two prospects near Southern Cross, South Venus and Leviathan, shows that ground magnetic surveys are useful for lithological mapping and structural interpretation, and potassium alteration associated with gold mineralisation can be mapped directly using radiometric surveys. Radiometric measurements indicate that potassium signals of up to 5%eK are associated with wallrock alteration adjacent to gold mineralisation, whereas the potassium signal from the main mineralised zone is close to 0%eK. Potassium signals associated with alteration are generally two to five times the width of the zone of gold mineralisation. Comparison of surface and drillhole radiometric sampling indicates that weathering does not seriously effect surface radiometric surveys except where transported soils cover the residual weathered profile.