Element mobility in the weathering environment and surface vectors to mineralisation-A case study from the Mashitu South Cu-Co deposit, Katanga, Democratic Republic of Congo

摘要

The Cu-Co deposits of the Katangan Copperbelt are affected by a deep chemical weathering regime. Meteoric fluids leached mobile elements from the near-surface environment and have redistributed them further down, forming remobilised supergene Cu deposits at a depth of similar to 30-50 m which are highly economic. The same process has caused residual enrichment of less mobile elements such as Co, forming 'cobalt caps' in the nearsurface above such supergene Cu deposits. Elements which are associated with hypogene Cu-Co mineralisation, but which are relatively immobile during supergene alteration, can make effective surface vectors to buried supergene Cu deposits; especially where these deposits have experienced a high degree of leaching and where high regional background Cu concentrations obscure surface Cu anomalies.