| Jiama copper polymetallic deposit is a typical and unique porphyry-skarn type ore deposit in the Gangdise metallogenic belt of Tibet. The ore reserves of copper, molybdenum, lead and zinc and associated gold and silver have already reached large and super-large scale. Therefore, to carry out detailed research on the ore mineralogy and mineralogy, not only has an important significance to Jiama deposit, but also to those mineral deposits in Gangdise polymetallic metallogenic belt which have world-class scale of copper, lead, zinc, iron, gold and silver. After fully collecting, analyzing and summing the formers' data and research results, moreover, lots of field work were completed, containing 30 thousand meters core geological logging,1000 pieces of field photos, appraisal of 253 pieces of polished section of the ore, electron microprobe analysis of 500 points, and testing of 10 pieces of single minerals, this paper has got some progress following.The types of ore-bodies have been classified and ore fabrics and component of ore mineral have been ascertained. The Jiama copper polymetallic deposit are mainly consisted of skarn-type Cu-Mo-Pb-Zn-Au-Ag polymetallic ore-body, hornfels-type Mo (Cu) polymetallic orebody and deeply buried porphyry-type molybdenum (copper) ore-body. The ores are dominated by ore structures produced by magmatic hydrothermal, including disseminated structure, massive structure, veinlets-stockwork structure; the ore textures are mainly metasomatic texture, crystalline texture, solid-solution separation texture, and so on. There are about 60 kinds of metallic minerals in the deposit, mainly containing bornite, chalcopyrite, molybdenite, tetrahedrite, galena, sphalerite, chalcocite, alpha chalcocite, covellite, azurite, malachite, natural gold, natural silver and sulfosalt minerals; non-metallic minerals including mainly garnet (andradite, grossular), wollastonite, diopside, tremolite, epidote and other skarn minerals, subordinately quartz, feldspar, calcite, biotite, sericite, chlorite, anhydrite, fluorite, kaolinite. This mineral deposit has experienced four mineralization periods of magmatic stage, skarn stage, hydrothermal stage and supergene stage, in which the hydrothermal stage can be divided into Cu-Mo sulfide phase, copper sulfide-sulphosalts mineral phase, Cu-Pb-Zn sulfide phase and gold mineralization phase, and the typical mineral assemblages in each mineralization phase have the obvious trend features of varying from high temperature to low temperature.The types of minerals and composition characteristics have been ascertained, also. In this ore deposit, the skarn minerals are a set of andradite-grossular-diopside-wollastonite assemblage, belonging to typical calcium skarn combination and forming in the medium-high temperature conditions of 450℃-700℃. The emulsion-like, lattice-like and leaf-shaped solid-solution separation textures are widely developed in the ores of this mineral deposit, in which bornite-chalcopyrite, bornite-chalcocite and bornite-wittichenite served as host and guest crystals each other. And the solid-solution separation textures formed by the copper-bearing minerals mentioned above have indicated that, the mineralization temperature are mainly medium-high temperature conditions(475℃-225℃). And the temperature mentioned above has suggested that, this ore deposit is not formed by hydrothermal sedimentary exhalative processes, but has indispensable genetic relationship with magmatism.Through systematic electron microprobe analyses on garnet, pyroxene, wollastonite, bornite, chalcopyrite, molybdenite and so on, this paper has made some conclusion. First, comparing with light zonation in garnets, the contents of SiO2, TiO2, Al2O3 are lower in dark zonation, while the contents of TFeO, Mn, Ti are higher. All of these phenomenon showed that the physic-chemical condition had been changed during the crystallization of garnets. Second, diopsides in Jiama ore pyroxene are mainly diopside and their ratios of Mn/Fe mainly varied from 0.17～0.50 except two tested points (with the ratios of 1.18 and 0.80). The characteristics of ratios of Mn/Fe have shown Jiama ore deposit was a typical polymetallic deposit. The color difference of bornite is caused by precipitation of solid-solution composition, Fe content and different formation temperature, and changes from the low content of to high content of Fe induced reflected colors varying from blue-purple to purple to brown red. Third, contents of Ag and zn in chalcopyrites occurred in granite-porphyry were higher than chalcopyrites occurred in hornfels and skarn. Whereas the content of Au in chalcopyrites occurred in hornfels was higher than those occurred in granite-porhpyry and skarn.The sources of ore-forming fluids and mineralization materials have been fully analyzed by comprehensivly summing up the formers' analytical data about H-O-S-Pb isotopes. Through combining with the related researches about the mineralization age and the evolution of ore-forming fluids and so on which have been carried out by the project team, the genesis of Jiama ore deposit has been discussed deeply, and it is found that the formation of this ore deposit was closely related with miocene magmatism, and the genetic type of Jiama ore deposit belongs to porphyry-skarn type.
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