Geochemistry And Evolution Of Ore-Forming Fluids At Baogutu Porphyry Copper Deposit, Xinjiang Province

Baogutu large deposit is located in the east end of Balkhash - Junggar porphyry copper belt,which is another large porphyry copper deposit in west Junggar of Xinjiang following the discovery of Tuwu copper deposit in eastern Tianshan. The found of Baogutu that not only provide a model for the experience to looking for porphyry copper deposit in Xinjiang, and also the key to study porphyry copper deposits in neibourhood regions of Central Asia.This paper is based on the State Project 305, "West Junggar Tarbagatay - Baerluke along the porphyry copper (molybdenum, gold) deposits and large deposits in terms of evaluation techniques and application of target", in collecting and collateing data on the basis of predecessor, through field investigation,and the combination of electron probe, observed and analyzed petrologic characteristics and mineralogical characteristics of the deposit.In the systematic study of the fluid,analyzed the ingredients,and evolution of ore-forming fluids,give to the physical and chemical conditions.By the determination of pyrite and chalcopyrite mineralization Pb isotope to trace the sources of fluids, the final identify the genetic model of deposit. After nearly two years of work, the main conclusions are:1. Determinated Plagioclase numbers, the results show that the majority of feldspar are andesine and oligoclase, the numbers of ring structures from the edge to the core to rise, from oligoclase to andesine transition.2. Primary fluid inclusions in microtemperature measurement through mineralization at different stages in different quartz sulfide vein system, the results show the role from the fluid temperature of the early to late stage showed an overall decreasing trend.3. For a single fluid inclusions by laser Raman spectra of its components, the results show that different type at different stages of quartz sulfide vein system of the liquid and gas components are similar,gas from the CH₄, N₂, C₂H₄, H₂O, CO₂ and CO₃^2- to the rich,the main features of organic ingredients including; liquid ingredients over a single, from the H₂O and CO₃^2-.4. Pyrite and chalcopyrite were measured Pb isotopes show that the minerals of ore-forming fluid from the mantle.