PLATINUM-GROUP MINERALS IN THE NEOPROTEROZOIC STRATABOUND COPPER-SILVER MINERALISATION, THE KALAHARI COPPERBELT, NORTHWESTERN BOTSWANA

摘要

The Neoproterozoic Ghanzi Group metasedimentary succession, of northwestern Botswana shows a potential for hosting precious metals. Platinum group minerals (PGM) were discovered in the Quirinus Prospect of the Boseto Exploration Area during preliminary stages of research into copper-silver mineralisation in the D'kar Formation. The PGM are associated mainly with molybdenite, bismuth-bearing minerals and copper sulphides. The combination of reflected light microscopy and SEM-EDAX analyses revealed a presence of Pd-Hg tellurides occurring together with molybdenite and Bi-bearing minerals forming a veinlet cross-cutting a larger quartz-calcite vein. The BSE image shows two mineral phases of diversified chemical composition with concentrations of Pd and Hg reaching maximum of 45.82 weight % and 21.41 weight % respectively.