The Khandiza Zn-Pb-Cu-Ag VMS deposit: Part of a new ‘Bathurst District’ in southern Uzbekistan?

The Lower Carboniferous Khandiza VMS deposit is located in southeast Uzbekistan close to the border with Tajikistan. Currently awaiting development by Marakand Minerals Limited (“Marakand”), the deposit comprises more than 14 Mt of resource grading 7.2% Zn, 3.5% Pb, 0.9% Cu, 130g/t Ag and 0.4 g/t Au. The deposit is hosted in Lower Carboniferous (Visean) rhyolite and dacite extrisives and pyroclastics, closely associated with a rhyolitic subvolcanic system. Geochemistry suggests the volcanics show both tholeiitic and calc-alkaline affinity, consistent with being forming in a rifted continental margin above the south-facing active destructive plate margin to the north of the Paleotethys Ocean. The sulphides form multiple lenses of massive banded ore with sulphide-cemented clastic volcanic breccias and footwall disseminations. Mineralogy of the sulphides is fairly simple comprising sphalerite, galena, chalcopyrite and pyrite with minor sulphosalts. Silver reports to sulphosalts and galena as well as other minor silver-rich sulphide phases. Minor gold appears to be paragenetically late. The Khandiza region has many features comparable to the Bathurst district of Canada where rifting at a supra-dubduction continental margin is responsible for generating the host volcanics to deposits such as the Brunswick 12 deposit. In southern Uzbekistan, Khandiza is the only VMS deposit that has so far been well explored. A further 34 mineral occurrences and base metal anomalies have been identified, all associated with volcanics, and warranting further exploration. 12 of these targets are within 10km of Khandiza itself, and associated with the Chornova volcanic complex.