Abstract

The Pan-African Lufilian fold belt hosts extensive and rich polymetallic mineralization, dominated by Cu-Co and Zn-Pb sulfides, U oxides, and noble metals. Stratiform, vein, and skarn deposits are present in the late Proterozoic rocks of the Katangan Supergroup. Mineralization is regionally widespread.The sedimentary basin evolution included three phases. The first two, characterized by rift-fault-controlled rapid subsidence followed by slower thermal subsidence, were associated with bimodal magmatism and probably related to two thermal events. The third phase reflects the onset of tectonic deformation and uplift in the southern part of the basin.The stratiform mineralization, emplaced before the folding of the basin, is concentrated in lithologically varied permeable rocks of the Roan Group that underlie the impermeable rocks of the Lower Kundelungu Group. The stratiform mineralization was emplaced by convective circulation of basinal brines forced by a thermal gradient created by a wedge-shaped lithosome of Lower Kundelungu pelitic rocks with low thermal conductivity. Hypabyssal igneous intrusions and volcanic and volcaniclastic rocks were the source of metals. The metals were introduced to the aquifer horizons saturated with basinal brines by hydrothermal circulation associated with the hypabyssal intrusions and by compactional dewatering of a 5,000-m-thick body of pelitic rocks rich in volcaniclastic material.Vein mineralization, located on major late faults, resulted from regional metamorphism-driven dewatering of the folded basin. The skarn-metasomatic mineralization is associated with small post-Katangan acid intrusions and blocks of thermally rejuvenated basement.Details of the distribution of mineralization are stratigraphically and structurally controlled.

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