Research On Metallization Of The Huangshaping Tungsten Polymetallic Deposit,Hunan Province,China

Hangshaping tungsten polymetallic deposit is a typical skarn-hydrothermal type W-Pb-Zn polymetallic deposit,located in the middle part of the Nanling metallogenic belt,and adjoins the Qitianling granites and Xintianling-Shizhuyuan W-Sn polymetallic metallogenic belt in the Southeast.The mineralization of Hangshaping tungsten polymetallic deposit is related with granite porphyry.Some problems about the mineralization process of Hangshaping tungsten polymetallic deposit needs further research.Based on the analysis of previous research results,together with field geological investigation and laboratory study,and used the basic theory of regional metallogeny,metallogenic evolution system,prospecting prediction theory as a guidance,the characteristic and evolution process of magma,fluid,strata and structure of Hangshaping tungsten polymetallic deposit and theirs relationship with mineralization are researched.Finally,this paper discussed the metallogenetic mechanism and pointed out the“trinity model”of geological prospecting prediction.Huangshaping deposit with special mineralization characteristics is a representative tungsten polymetallic deposit in Naling Range area,it is enrichment of Pb-Zn and it's metallogenic geological body is granite porphyry.There are two types of ore-bodies in the Huangshaping deposit:skarn type ore-bodies occurred in the internal or external contact zone of granite porphyry and Pb-Zn?Ag?type ore-bodies occurred in the limestone of Lower Carboniferous Shidengzi Formation.The distribution of granite porphyry and granophyre is controlled by the NNW and NNE trending structure which constitutes ore-forming system.According to the ore-bodies spatial distribution feature,the relationship between mineralization and granite porphyry and the F1 fault,the whole mining district is divided into 301 and 304metallogenic belt.The 304 metallogenic belt lied in the west of quartz porphyry and arounds granophyres which has large-scale skarnized belt with iron and a little of tungsten polymetallic ore bodies.The 301 metallogenic belt lied in the east of quartz porphyry and arounds granite-porphyry which has larger-scale of skarnized with iron and W-Mo polymetallic ore bodies.The research on the petrography,mineralogy and petrological geochemistry of magmatic rock of Huangshaping ore deposit show that the granodiorite is the result of remelted magna of deep-metamorphic-ancient rock which is remelted by the mantle materials upwelling in intraplate extensional environment in early Yanshanian.In Huangshaping area,there have been three stage magmatic eruptions:quartz porphyry formed in the first stage,granite-porphyry and granophyres formed in the second stage and dacite porphyry formed in the last stage.The three stage magmatic eruptions are derived from the same magma source and have the characteristics of A-type granite.In the late stage of magmatic evolution,the contained F rich silicon magma was formed by the liquid immiscibility of parent magma with strong magma cryptoexplosion.The part of the post-magmatic fluid was emplaced at the contact zone between rock mass and surrounding rocks,and the another part post-magmatic fluid was filled into surrounding rocks fracture which was caused by explosive,and then the large-scale skarnization contains garnet and diopside was formed.The isotopic data of S and Pb of Huangshaping ore deposit suggest that the magma of Huangshaping deposit was mixted by the mantle-crust materials in upwelling process,and accepted massive sulfur with high value of?³⁴S which occurred in Devonian.In the process of magma emplacement and mineralization,the magma also affected by the surrounding rocks.Some materials such as Pb and S from Devonian participated in mineralization.The characteristics of fluid inclusions show that ore-forming fluid salinity decreased with the falling temperature.However,they are differences between the W-Mo ore-forming fluid and the Pb-Zn ore-forming fluid.The salinity of W-Mo ore-forming fluid is rapid decreased with the falling temperature in high temperature stage,and tended to be stable in low medium temperature stage.But,the salinity of Pb-Zn ore-forming fluid formed in intermediate and advanced stages of skarn type mineralization is lower than that of W-Mo ore-forming fluid.The reason for the difference between W-Mo ore-orming fluid and the Pb-Zn ore-forming fluid is the mixture of ore-forming fluid and the adding of magmatic water.Through the further study of this work,we revealed the metallogenic geological bodies,metallogenic structure,metallogenic structural plane and characteristics of mineralization,and established the“trinity model”of geological prospecting prediction.