Research on ore-forming hydrothermal fluids in the Kansanshi deposit (Solwezi-NW Zambia)

Kansanshi Cu-(Au) Mine located in the Domes region is hosted by strongly deformed Neoproterozoic metasediment in the Katanga basin in the southern part of Africa and it's a structurally controlled deposit. The Kansanshi Mine is located in the Central African Copper Belt, Northwest province of Zambia, and is known as a sedimentary stratiform copper deposit formed 880-580 million years ago in the Neoproterozoic Era which is currently the second largest copper-producing deposit in Africa. The Kansanshi Mine experienced a sedimentation period during the Neoproterozoic Era where carbonates, sandstones, and shales as sedimentary rocks were deposited, later the sedimentation period gave rise to the stratiform copper mineralization within the sedimentary layers because of the hydrothermal fluid-rock interaction. Kansanshi deposit is a complex deposit comprising sediment-hosted and vein-hosted which have been overprinted by breccia, and supergene mineralization leading to secondary copper mineralization at Kansanshi. The deposit is characterized by high-sulfidation mineralization as evidenced by the chalcocite, covellite, and enargite minerals that are typically formed in highly acidic environments usually with temperatures ranging between 100°C -300°C. The fluid inclusion studies of quartz and calcite both yielded between 0-500 °C. The study analyses a mineral sample's X-ray diffraction (XRD) pattern. XRD is used to identify the crystalline phases present in a sample by measuring the diffraction patterns of X-rays directed at the sample. XRD analysis was performed on three samples, Albite was identified in all three samples, suggesting that the samples may have been derived from a granitic or metamorphic origin, Scanning Electron Microscope (SEM), Laser Ablation Inductively Coupled Plasma Mass Spectrometer (LA-ICP-MS), and isotope geochemistry analyses. In the liquid inclusion studies, it was determined that quartz minerals have a temperature range between 156-500+°C (Avg. 219,244°C) and calcite minerals have a temperature range between 156-500+°C (Avg. 250°C). Salinity ratios in quartz minerals are between 3,6-57.2% NaCl and in calcite minerals are between 30,4-52% NaCl. Carbon and oxygen isotope geochemistry analysis revealed that the calcites are between marine limestone and igneous calcite (skarn zone). These values representing skarn-type calcites indicate an igneous source.