Characteristics of fluid inclusions and genesis of Xuejiping copper deposit in northwestern Yunnan Province

Xuejiping copper deposit is a porphyry type deposit that occurred in quartz monzonite diorite porphyry-quartz diorite porphyry-quartz monzonite porphyry intrusive complex. The formation of it experienced multi-stage hydrothermal mineralization,mainly including micro-fine vein disseminated pyrite ± chalcopyrite-quartz,fine veinlet molybdenite ±( pyrite) ±( chalcopyrite)-quartz,micro-fine veinlet sulfide-poor quartz-calcite. The comprehensive study on petrography,microthermometry,laser Raman and carbonhydrogen-oxygen isotopes of fluid inclusions showed that there are mainly halite-bearing three-phase and aqueous two-phase two types of fluid inclusions developed in micro-fine vein disseminated pyrite ± chalcopyrite-quartz,which is similar to the fluid inclusions in quartz of ore-bearing quartz monzonite intrusion,so the ore-forming fluids are of medium to high temperature,high salinity NaCl-H2O type solutions and mainly came from the ore-bearing late Indo-Chinese intrusions. There are mainly CO2-bearing three-phase and aqueous two-phase fluid inclusions developed in molybdenite ±( pyrite) ±( chalcopyrite)-quartz,and the ore-forming fluids are of medium temperature,low salinity NaCl-CO2-H2O type solutions,a different origin is conferred. Only aqueous two-phase fluid inclusions were observed in sulfide-poor-quartz-calcite,the ore-forming fluids are of low to medium temperature,low salinity Na Cl-H2 O type solutions and might mainly come from meteoric water. So Xuejiping copper deposit was the product of metallogenic superimposition of differentsourced with different geochemical characteristics magmatic solutions.