Platinum mineralization in quartz veins near Naboomspruit, central Transvaal

Quartz veins which transect felsites and sandstones of the Transvaal Sequence near Naboomspruit contain locally high concentrations of platinum. These were exploited between 1924 and 1926 by Transvaal Platinum Ltd. This article details the results obtained from a preliminary geochemical and mineralogical investigation of material, from the Waterberg mine site, which was donated to the University of Cape Town in the late 1920s. Platinum-group element (PGE) analyses carried out on bulk samples indicate that PT is markedly enriched relative to all of the other noble metals and this strongly distinguishes the Waterberg veins from other hydrothermal, quartz-hosted noble metal deposits. The mineralogy of the veins is compatible with the passage of a highly oxidized fluid which contained significant concentrations of Pt, Pd, and Au. It is speculated that precipitation of the metals took place in response to a reduction in Eh and/or an increase in the pH of the fluid. -from Authors