Characteristic Of Fluid Inclusions In Dawangshan Tungsten Polymetallic Deposit In Central Jiangxi Province And Their Gelogical Significance

Dawangshan Tungsten Polymetallic ore district is located at edge of Yihuang,Lean,Chongren,lied in the central part of Jiangxi Province,the southeast of China.It belongs to the north of themolybdenum tungsten ploymetallic mineralization zone of Dawangshan-Yushan.Ore type is mainly wolframite and the orebodies in this deposit mainly occurr in the contact zone of granite.Based on the analysis of the geological backgroud and the metallogenic characteristics of Dawangshan Tungsten Polymetallic ore district in this paper,according to previous studies of petrologic geochemistry,zircon U-Pb geochronology characteristics on fine griant two-mica alkali feldspar granite,fluid inclusions and stable isotope researches are systematically carried out to understand the characteristics of ore-forming fluids and metallogenic material source of dawangshan tungsten polymetallic deposit and discusse rock formation age,genetic types and tectonic environment.The metallogenic model of the district is preliminarily established.It is helpful to the formation of metallogenic theory and mineral exploration in the study area.The following is the main achievements of this study.?1?According to previous studies?project group?on the study of the Shanxin granite body,it has high potassium calc alkaline,metaluminous peraluminous,major elements of silicon rich alkali,poor calcium magnesium,high Mg Fe characteristic index and belong to S type granitic rocks with high differentiation.It has the characteristics of crust source granite and belongs to high thermal granite.The source rocks may be altered sedimentary rocks.?2?Temperature measurement of quartz fluid inclusions in Dawangshan Tungsten Polymetallic ore district shows that the homogenization temperatures of ore-forming fluids were respectively in the range of 180²80??peak value of 190 210 C?;the salinity of fluid inclusions ranged from7.86%²0.22%NaCleqv?peak value of 11¹7%NaCleqv?.Themetallogenic temperature is 315 339 by using the sulfur isotope ?thermometer belonging to the moderate-high temperature,and moderate-high salinity deposit;Quartz inclusions temperature salinity diagram shows the ore-forming fluid mixed with low temperature,low salinity fluid.In the process of evolution of ore-forming fluid,fluid mixing and natural cooling may be experienced.In the process of magma liquid immiscibility,W,Mo and other polymetallic ore-forming elements and volatile elements are enriched,then the quartz vein type tungsten polymetallic deposit was formed.?3?Through the stable isotopes of Dawangshan ore district studies have shown that the hydrogen and oxygeon of fluid influsions aqueous is ?DV-SMOW =-72.5‰^-93.1‰,?18OH₂O =-2‰ 1.8‰.It shows the ore-forming fluids in the crystallization of wolframite is relatively single,mainly magmatic water,and the ore-forming fluid of quartz crystal was the magmatic water mixed with meteoric water.The ?34S values of sulfide range from-1.3‰ to +1.9‰,Which between-1‰⁰.6‰ in the majority,with an average of-0.22‰,mainly concentrated in the near zero,the sulfur source associated with deep magma.The data are mainly concentrated in the near zero,which shows the sulfur source associated with deep magma.?4?Based on the comprehensive study of the geological characteristics,ore-forming materials,ore-forming conditions,tectonic setting and metallogenic mechanism of Dawangshan tungsten polymetallic ore district,the metallogenic model of the deposit is established.