Age of granites from the Chambishi copper mine in Zambia and its implications

The Chambishi copper mine in Zambia is located in the central Africa copper-cobalt metallogenic belt. The bedded orebodies occur in the Neoproterozoic sandshales of Roan Formation. The Roan Formation unconformably overlies the Early Proterozoic sandy conglomerate of Muwa System, which in turn overlies the lower Chambishi granite basement. U-Pb zircon dating yielded the age of 1984 ±6-1986 ±6 Ma for Chambishi granite, and the upper age limit is 1932 ±8 Ma for Muwa System. The lithogeochemistry and chondrite-normalized REE patterns of Chambishi granites have the characteristics of S-type granites. Combined with the data of regional geological evolution, the authors believe that Archean Congo craton may have experienced activation over a large area during Early Proterozoic period, and a stable ancient block had been formed in the Early Proterozoic period.