Significance of ferruginous pisoliths and interface sampling for gold exploration in the covered terrains

The deeply weathered Yamarna Terrane is the easternmost, least explored Terrane of the Yilgarn Craton in Western Australia. Investigation of the landscape evolution, mineralogy and geochemistry of the transported cover showed that the near surface ferruginous regolith can provide a significant tool for exploration under cover. Three types of ferruginous materials were identified and examined in three gold prospects: Smokebush, Toppin Hill and Santana. The ferruginous materials include: 1) lateritic residuum and its detrital ferruginous clasts of underlying or nearby bedrock; 2) authigenic pisoliths and nodules of Permian glacial sediments (PPS); and 3) authigenic pisoliths of aeolian sand (PAS) overlying the other two. Our findings show that As is the main pathfinder element for Au mineralization. Arsenic and Au are elevated and form near surface anomalies in lateritic residuum, detrital ferruginous clasts, PAS,