An integrated geological and geophysical study of the Deblin Copper Mine are in Kombat South, Southern Otavi mountain land, Northern Namibia

Abstract

The Deblin Copper Mine is located at the transition between the Swakop rift-basin and the carbonate platform of the Otavi Mountain Land. Copper and zinc mineralization occurs mainly in carbonate host rocks close to a major thrust fault underlain by bimodal metavolcanics with mineralized quartz-calcite veins. Copper sulphides of chalcopyrite and bornite occur as disseminated and vein-type mineralization associated with sphalerite and pyrite. The area is characterized by outcrops of carbonates and limited metavolcanics. Wall rock alterations include sericitization and chloritization of metavolcanics, as well as silicification and dolomitization of carbonates. Vein type mineralization is characterized by a relatively narrow range of sulphur isotopes (δ34S = -4.9‰ to +6.0‰) compared to that of disseminated sulphides (δ34S= -9.99‰ to +3.63‰). The two sulphur isotope ranges suggest that both magmatic and sedimentary sulphur sources were involved in the genesis of the deposit. Geochemical and petrological data suggest that the metavolcanic rocks in the area formed as alkali basalts in an oceanic island geotectonic setting. Magnetic data revealed concealed faults which may have acted as conduits for mineralizing hydrothermal fluids. The deposit shows ore forming processes associated with both VMS and MVT-type mineralization