Geochemistry of the Jinman Vein—Type Copper Deposit,Western Yunnan Province,China——I.Element Geochemical Characteristics

The Jinman copper deposit,which is situated on the northern margin of the Lanping-Simao back-arc basin,western Yunnan Province,is a silver-bearing,high-grade vein-type copper deposit.Comprehensive element geochemical studies of the host rocks and hydrothermal minerals revealed the regularities in the distribution,mobilization and transport of elements from the host rocks to hydrothermal minerals.In conjunction with the fluid inclusion and isotope data,it is suggested that the ore-forming fluid was derived mainly from a deep source characterized by CO2 enrichment and reduction in nature.It is also suggested that the oreforming materials come largely from a deep source.although the contribution of the country rocks should not be ruled out.It is also found that some hydrothermal minerals are possessed of MREE-enrichment patterns.It is deduced that the REEs in the deep-source ore fluid were transported in the form of CO3^2- complexes and were deposited in a continental basin(or a hot-spring basin).

Geochemistry of the Jinman vein-type copper deposit,western Yunnan Province,China— I. element geochemical characteristics

The Jinmen copper deposit, which is situated on the northern margin of the Lanping-Simao back-arc basin, western Yunnan Province, is a silver-bearing, high-grade vein-type copper deposit. Comprehensive element geochemical studies of the host rocks and hydrothermal minerals revealed the regularities in the distribution, mobilization and transport of elements from the host rocks to hydrothermal minerals. In conjunction with the fluid inclusion and isotope data, it is suggested that the ore-forming fluid was derived mainly from a deep source characterized by CO₂ enrichment and reduction in nature. It is also suggested that the ore-forming materials come largely from a deep source, although the contribution of the country rocks should not be ruled out. It is also found that some hydrothermal minerals are possessed of MREE-enrichment patterns. It is deduced that the REEs in the deep-source ore fluid were transported in the form of CO ₃ ²⁻ complexes and were deposited in a continental basin (or a hot-spring basin). This project was financially supported by the Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences.