An overview of carbonate-hosted mineral deposits in the Otavi Mountain Land, Namibia: implications for ore genesis

A model of metallogenesis for the carbonate-hosted base metal deposits of the Otavi Mountain Land (Namibia) is proposed based on stratigraphic, mineralogical, metal association, Pb and S isotope systematics and fluid inclusion data. Three mineralising episodes are recognised. The first involved low-temperature and high-salinity basinal fluids, which formed the Berg Aukas-type deposits of Mississippi Valley-Type (MVT) affinity. These are characterised by a Zn-Pb metal association. The second episode appears to have involved Cu-rich fluids having higher temperatures and lower salinities of possible metamorphic origin. These formed Tsumeb-type deposi ts, characterised by a metal association of Cu-Pb-Zn-Ag, locally accompanied by Fe-Mn oxides and silicates. The third and last episode is related to recent weathering, which resulted in the precipitation of V-rich minerals.