Isotope geochemical characteristics of Machangqing rock mass in western Yunnan and its implications

Machangqing Cu-Mo-Au polymetallic deposit is one of the most notable porphyry deposits in "Sanjiang" tectonic zone.Systematic research on isotopes such as S,H,O,Pb,C,He,Ar,Rb and Sr,and analysis on composition characteristics and evolution law of the isotopes,and the field geological research were conducted.Machangqing rock mass,which originates from enriched mantle at depth,are mixed with crustal materials during the upward penetration of mantle materials.Ore-forming fluid and materials of Cu-Mo mineralization originate from magma;ore-forming fluid and materials of hornfels-type and skarn-type Cu-Mo(Au) mineralization near the contact zone originate from magma and wall rock,and they are mainly magma;ore-forming fluid and materials of quartz vein type and fractured altered rock type Au mineralization in wall rock originate from magma and strata,and ratio of magma in the composition is decreasing.Hence isotope geochemical research is significant to the study of mineralization and genesis of Machangqing Cu-Mo-Au deposit.