GEOLOGICAL AND GEOCHEMICAL CHARACTERISTICS AND GENESIS OF Cu - Pb - Zn (-Ag) DEPOSIT IN YUNNAN COUNTY, YUNNAN PROVINCE

Maocaoping Cu-Pb-Zn (-Ag) deposit is located in Lanping Mesozoic-Cenozoic basins in western margin of the northern section. It is the newly discovered account of the causes of epigenetic hydrothermal filling a vein-type Pb-Zn (-Cu) vein-type orebodies and Cu (-Ag-Mo) orebody coexist polymetallic deposits. on the basis of summarizing the basin typical lanping Cu-Pb-Zn mineralization geological background and geological characteristics of the deposit metal deposits, systematically dissected the main section of the mine ore mine. Identification of ore mineralization zonation, fluid characteristics and metallogenic age. Initially established the genesis model.Paper obtained the following awareness and conclusions:(1) Mine is mainly exposed Cenozoic strata, Affected by shear tectonic setting of the Cenozoic, regional growth faults, and nearly north-south oriented, steeply dipping west, constitute the main ore control-host structures. Known ore bodies occur in the fracture zone directly and in the space of local capacity mine in fissures, cleavage and formation of hydrothermal karst collapse. Forming a brecciated, veined, infection ores, filling epigenetic mineralization characteristics significantly.(2) Region can be divided into vein-type ore of Pb-Zn (-Cu) and vein-type of Cu (-Ag-Mo). They are distributed in different ore block, ore mineral composition and its combination of elements are differences, formed sphalerite, galena dominated Pb-Zn-Cu-Ag combination and Chalcopyrite, chalcocite dominated Cu-Ag-Mo combination. The former mostly brecciated, weakly disseminated distributed in metamorphic sandstone and fault edge, According hand specimen and microscopic photos mineralization stages can be divided into:no ore quartz vein stage, quartz-sulphide stage, quartz-carbonate stage and oxidized ore stage. The latter mostly granular and fine veins, which located in the cleavage of calcareous argillite. The mineralization stages can be divided into:None ore Britain-carbonate veins stage, quartz-sulphide-carbonate veins stage, quartz-carbonate stage and oxide ore stage.(3) According to the occurring features of ore body, ore and rock fabric characteristics and tectonic deformation, deformation skarn, altered mylonite. Determined from the geological relations of the relationship between mineralization and structural deformation sequence can be constructed in the area has divided:Ministry syncline axis north-south and cleavages, the southwestern edge granite rock affected by the occurrence of structural deterioration, exposed gneiss, mylonite and other rocks, N-S trending ore-controlling fracture. (4) The type of fluid inclusions in the mine:pure liquid inclusions, gas-liquid two-phase liquid-rich inclusions, CO2-H2O inclusions, which mainly exist. According to the characteristics of the sampling location and type. Homogenization temperatures of fluid inclusions in quartz ranged between140.1～384℃. The salinity is between0.41-22.51wt%NaCl. Density ranged from0.65～1.00g/cm3. Is a rich CO2, middle-low temperature, low salinity fluid system. The main mineralization stage average homogenization temperature is282.88℃. The average salinity is7.92wt%NaCl. Density is0.86g/cm3. Ore-forming fluid homogeneous temperature and the salinity in mineralization stage is unlikely. In the general trend is exhibited high to low.(5) Zircon dating through the area southwest region of granite samples. Tu has a good positive correlation between U content, show the haracteristics of magmatic zircons. Preliminary locked the lead and zinc emplacement age is late than21.19Ma. Cretaceous strata ore body in northern Ar-Ar dating of muscovite displayed emplacement age late than19.54Ma.(6) Basied on the results, there are two times of Cu-Pb-Zn polymetallic mineralization.Among them, the Pb-Zn (-Cu-Ag) mineralization and inverse-based deformation slip away with the emplacement of magma activities.In Cu-Ag (-Mo) mineralization and later mainly go slip shear deformation related.Mineralization occurred mainly in the area after strong compression stress relaxation stage, rock and development of open space. It is easy-to-mineralization of the ore-forming fluid poured into the period. The awareness of a new understanding of the southeastern margin of Tibetan plateau and Lanping basins cenozoic massive Cu-Pb-Zn (-Ag) mineralization provide new ideas.