Re-Os and U-Pb dating of molybdenite and monazite frommineralized veins from the kansanshi copper deposit, Zambia

摘要

The Kansanshi Copper deposit in northern Zambia consists of high-angle sheeted veins and spatially associated disseminated sulfides which cut and replace metamorphosed Late Proterozoic Katangan sediemnts. Cross-cutting relationships have been used to delineate three stages of sub-parlalel veins. The first two vein sets are chalcopyrite-rich and contain minor molybdenite while the final set contains minor each fo the vein sets by Re-Os methods yield ages of 511.8+-1.7Ma, 512.9+-1.7 Ma, and 503.0+-1.7 Ma, respectively, consistent with relative ages observved from cross-cutting relationships. Monazite crystals from the final veining event were analyzed using the SHRIMP and yield a U-Pb age of 509+-11 Ma. These results indicate mineralization took place in the late Cambrian. The ages of mineralization at Kansanshi are boadly similar with those determined for other post-tectonic vein systems in the Central African Copperbelt.