Abstract: The authors present hydrogen, oxygen, carbon, sulfur and lead isotope compositions of the Xiaoxinancha goldbearing porphyry copper deposits, Yanbian. The concentrations of δ¹⁸Oquartzwater,δD andδ¹³CCO₂ trapped in quartz and fluid inclusions of the ores are -0.1‰ to +5.6‰, -77‰ to -38‰ and -5.6‰ to -3.5‰, respectively. And the δ¹⁸Ocalcitewaterand δD of calcite are -4.3‰ and -62‰. In addition, concentrations of δ¹⁸OCc,δ¹³CPDB,δ³⁴S trapped in calcites and sulphides are -4.3‰ to +11.39‰, -8.8‰ to -5.3‰, and +2.1‰ to +4.8‰, respectively.²⁰⁶Pb/²⁰⁴Pb,²⁰⁷Pb/²⁰⁴Pb,²⁰⁸Pb/²⁰⁴Pb ratios are 18.103 to 18.388, 15.405 to 15.590, 37.888 to 38.184 respectively with μ value varying from 8.52 to 8.79. The sulfur isotopic characteristics indicate that the oreforming fluids are similar to those of subcontinental island arc magmas, the oxygencarbon and the lead isotopic data reveal a primitive mantle source,and the hydrogenoxygen isotopic features show a complex fluid of the primary mantle,magmatic and metamorphic water, and with an evolutionary trendency towards meteoric and sea waters. So the authors suggest that the thermodynamic sources were derived from the primitive mantle, the oreforming fluids had been contaminated by meteoric hydrothermal system on the upper crust or near the surface during ascending, and the oreforming materials (such as Cu and Au) were from IMORB mantle.

Key words: H, O, C, S, Pb isotope, the genesis and evolution of orebearing fluids, goldbearing porphyry copper deposit, Yanbian area