View article

Variations of naturally emitted gamma radiation have been used in geological prospecting for over 20 years to detect anomalies associated with exploitable ore deposits. We examined their ability to detect spatial variation of soil material by comparing simultaneous ground and airborne measurements of gamma emissions with ground observations over a catchment in south-western Australia. Measurements were taken in the spectral windows for 40K, 238Uand 232Th. Variations of gamma radiation corresponded with the distribution of soil-forming materials over the landscape, and were used to distinguish between highly weathered residuum and fresh material from granitic outcrops. Gamma radiometric data also discriminated clearly between doleritic, lateritic and granitic soil parent materials. Airborne data indicated the distribution of these materials through the catchment, with the exception of dolerite dikes …