kaskara drilling --copper in first 3 metres, page-5

The composition of descloizite-mottramite in relation to the trace-element distribution of Pb, Zn, Cu and V in the Otavi Mountain Land, South West Africa/Namibia


W.A. van der Westhuizena, E.A.W. Tordiffea, H. de Bruiyna and G.J. Beukesa

Department of Geology, University of the Orange Free State, P.O. Box 339, Bloemfontein 9300, South Africa
Revised 15 December 1988.
Available online 22 April 2003.

Abstract

The carbonate rocks of the Otavi Group (ca. 800 Ma) in the northeastern part of South West Africa/Namibia are known to contain Pb, Zn and Cu sulphide deposits with the mining activities at Tsumeb, Kombat and Berg Aukas being the most prominent. Vanadium mineralisation, associated with karst development, is often associated with the sulphide deposits, but occurrences without a sulphide association are also present.

The distribution of Pb, Zn, Cu and V in the dolomite and limestone of the Otavi Mountain Land delineates geochemical regions which coincide with the above mineralisation. This coincidence is also manifest in the type of V mineralisation; where high concentrations of Zn occur in the country rocks, descloizite predominates, whilst mottramite occurs when the Cu values are higher.