The Geology And Geochemistry Characteristic In Xinjiang Western Tianshan Lailisigao’er Mo Ore Deposit

Lailisigao’er ore is located on the west part of Paleozoic Bolohuolo compositeisland arc zone which is in the north edge of Kazakhstan-Erie plate. Lailisigao’er is animportant Mo ore concentration area in western Tianshan. Based on the regionalgeology, mine geology of Lailisigao’er Mo ore deposit, through the study of ore fabriccharacteristic and minerals paragenetic association in principle metallogenic stage,using cold and hot machine technique, the fluid inclusion has been studied in thisdissertation. Combine the isotope research results, to find the relationship of fluid andmineralization, and also the source of metallogenic material, in order to improve theunderstanding of the ore deposit.Lailisigao’er Mo ore deposit is in the top or edge parts of the granodioriteporphyry, contact belts and wall-rock nearby, the ore deposit is in tabular, vein andlenticular shaped. The hydrothermal alteration possess the zonality, composed bysericitization zone, K-silicate zoneand propylitization zone, with sulfidemineralization, showing the disseminated (string disseminated), veinlet and stockworketc. various structure changes. Molybdenite, bornite, chalcopyrite and pyrrhotine arethe principle metallic minerals. Overall, Lailisigao’er Mo ore belongs to porphyryCu-Mo minerazation.The results of microthermometry temperature indicated that, the W-shapedinclusions homogenization temperature of potassium quartz vein is between220～400℃, which in ore-bearing quartz is between160～380℃. And in quartz-calciteveins, the homogenization temperature of W-shaped inclusions varies between110～280℃. Their salinity range is4.65～11.13%NaCl.eqv,4.03～10.24%NaCl.eqv,3.06～8.28%NaCl.eqv respectively. The ore-forming fluid has the property of medium-high temperature, low salinity and low density, the ore deposit forming depthis1.5km～3.5km.The H-isotope and O-isotope results show that the O and H isotope compositionof ore-forming fluid is magmatic water and atmospheric precipitation. In themetallogenic stage, the magmatic water is the main part and mixed little atmosphericprecipitation. S-isotopic and Pb-isotopic composition results show that S isoriginated from deep seated magma source mixed formation sulfur, which means theOre-forming process could be related to subduction of oceanic crust produced by themolten lava, and the Ore-forming metallic element has the characteristic of the crustand mantle mixture may come from the molten magma.As stated above, Lailisigao’er Mo ore deposit is typical porphyry Cu-Mo oredeposit.