This study focuses on the mineralization and fluid evolution of deposits in the Katanga Copperbelt, DR Congo, where two main hypogene mineralization stages have been proposed. Each of these events presents distinct signatures of fluid salinity and temperature: the first occurred during diagenesis, with a low salinity of 1.2 to 20.9 wt % NaCl equiv and a low temperature of 80° to 252°C; the second took place during maximum burial and orogenesis of the sedimentary strata, with a higher salinity of 32.3 to 59.6 wt % NaCl (+ KCl) equiv and higher temperature of 209° to 359°C. These later high-temperature, high-salinity fluids pervasively affected the first stage of nodules and lenses hosting ore minerals, which is confirmed by the extensive recrystallization features of carbonates in mineralized nodules and veins, reflecting multiple growth phases. Elemental composition assessed through laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses in fluid inclusions provides evidence for fluids enriched in K, Ba, Cu, Co, Pb, and Zn. Albitization of K-feldspar during water-rock interactions most likely caused the strong enrichment in potassium and barium. The high metal concentrations measured in the fluid inclusions are interpreted to result from the intense leaching of metals from the basement rocks and the overlying siliciclastic sedimentary sequence by descending Cl-enriched brines.

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