The Mineralogical Characteristics And Its Genetic Significance Of Pusangguo Copper Poly-metal Ore Deposit In Tibet

Located in the Nanmulin Country, Tibet, the Pusangguo copper polymetallic deposit is a skarn-hydrothermal vein type deposit, which belongs to eastern part of the Gangdese belt.The ore minerals composition and the occurrence states of Co-Ni were systematically studied in this paper:The types of ore-bodies have been classified. The deposit is mainly consisted of chalcopyrite-galena-sphalerite type ore body, sphalerite-chalcopyrite ore body, and chalcopyrite-pyrite type ore body.The ore fabrics, ore textures and component of ore mineral have been ascertained. The metallic minerals in the deposit mainly contain chalcopyrite, pyrite, galena, sphalerite, marmatite, pyrrhotite, covellite and cobaltite. Non-metallic minerals include mainly garnet, quartz, calcite, epidote, chlorite and other clay minerals.The Ores are dominated by ore structures produced by magmatic hydrothermal, including massive structure, disseminated structure, veinlets-stockwork structure.The ore textures are mainly crystalline texture, metasomatic texture and solid-solution separation texture.The occurrence states of Co-Ni revealed by means of microscope and scanning electron microprobe indicate that Co-Ni are mainly present as cobaltite. The results indicate that there is a new type mineralization in the Gangdese belt, and supply important information for further exploration. This deposit has experienced4mineralization periods of magmatic stage, skatn stage, hydrothermal stage and supergene stage, in which the hydrothermal stage can be divided into Quartz-sulfide phase, sphalerite-chalcopyrite phase, and sphalerite-galena phase.The typical mineral assemblages in each mineralization phase have the obvious trend features of carrying from high temperature to low temperature.The emulsion-like, lattice-like and leaf-shaped solid-solution separation texture are widely developed in the copper-bearing minerals mentioned above have indicated that, the mineralization temperature are mainly medium-high temperature conditions(350℃-400℃), which has suggested that this deposit has indispensable genetic relationship with magmatism, and the genetic type of Pusangguo ore deposit is skarn type.