GOLD ORE DEPOSIT OF SABODALA (WESTERN SEN EGAL) - VEIN MINERALIZATIONOF HYDROTHERMAL ORIGIN REMOBILIZED BY A SHEAR ZONE

The Sabodala Au sulphide deposit, occurring in the Birimian terranes o f the Mako Supergroup (East Senegal), appears as hydrothermal quartz v eins associated with felsic volcano-detrital rocks (tufs and rhyodacit ic lavas) enclosed in tholeiitic formations (metabasalts, quartzic mic rodiorites). The hydrothermal mineralisation, constituting auriferous pyrite, is disseminated in the siliceous-carbonate stockwork and in th e host rock. The albitised terms of the stockwork might indicate the p resence of gold. The mineralization is then remobilised by the NS/N20 Sabodala Shear Zone. This hydrothermal stage is marked by a successive open-space filling deposition of sphalerite, galena, chalcopyrite and a second generation of more argentiferous native Au associated with m inor quantities of combined forms (e.g. petzite, stromeyerite). The mi neralised facies are essentially the acid lavas and pyroclastics and a lso the margins of the quartz veins. (C) 1997 Elsevier Science Limited .