The Metallogenic Geochemistry And Significance Of Prospecting Of Gold Polymetallic Ore Concentration Area In Beiya In Western Yunnan Province

Beiya gold-polymetallic deposit is one of typical deposits related to alkali-rich intrusion of the Cenozoic in western Yunnan, so it has been a research focus to scholars for a few years. In order to discuss the relationship between mineralization and alkali-rich porphyries, and investigate genetic relation among various ore types, this article studies geologic features, spatial distribution, fluid inclusions, isotope geochemistry of Beiya deposit, and concentrates on the study on spatial distribution, extensive field investigation of different ore blocks. Besides, the source of the mineralization fluid and ore-forming materials is also studied . On the basis of this study, a metallogenetic model is proposed for Beiya gold-polymetallic deposit, which focuses on metallogenesis system related to alkali-rich intrusion, ultimately this model will manage to provide the scientific evidences and theoretical foundation for prospecting the same genetic type deposits in Beiya ( especially in the outlying area). Based on the above-mentioned research, the following conclusion is reached:On the basis of demand for classification of genetic types , we have developed detailed field investigations about various ore blocks, especially about the geological phenomena exposed by the new exploitation, and then integrated comprehensive analysis of the existing geological data and the results of previous studies. Based on the above-mentioned research, we categorize gold-polymetallic deposit in Beiya two metallogenic series, namely, porphyry and epigenetic metallogenic series in accordance with structure and natural type of ore, spatial distribution of ore bodies, metallogenic geochemistry characteristics, features and assemblage of ore-bearing strata. And it proposed a metallogenetic model for Beiya gold-polymetallic deposit.There exists 3 types of fluids, namely, the high temperature , high salinity fluids ; the medium-high temperature ,high salinity fluids; the medium-low , low salinity fluids. Researches show that the ore forming fluids are of NaCl-H2O types, the homogenization temperatures range from 132℃to﹥550℃, the salinities are in the range of 1.9～61.1 w(NaCleq)%. It shows that that the ore-forming fluids related to the alkali-rich porphyry differentiation.The S, Pb isotopic composition of pyrite, galena, chalcopyrite in ore suggests that in metallogenic process the alkali-rich porphyries in this area not only provide power and thermal energy, but also are main source for the mineralization resources and fluid resources.By the research in metallogenic model of the area, it suggests that the deep of Wandongshan and Hongnitang ,Tanyao,Matouwan,Nandaping have the good potential of polymetallic ore deposit...