The Research On Fluid Inclusions Of The Zuoba Greisen Type Tungsten Deposit In Southern Jiangxi

Zuoba tungsten deposit is located in Chongyi-Dayu-Shangyou ore district,Southwest of Xihuashan-Zhangtiantang tungsten tin belt,and north of ore field in Xihuahsn-Piaotang.The upside in deposit is a quartz vein type,and the bottom is greisen type.Except Quaternary Holocene strata(Q4),there were Middle-lower Cambrian strata(?1+2)in deposit area.The mining area is in a strong tectonic activity,and its formation is influenced by strong tectonic-magmatic activity in the area.In this paper,through the reseach of fluid inclusions in Zuoba greisen tungsten deposit Southern Jiangxi(petrography,micro-temperature measurement,gas-liquid phase composition analysis,rare earth,trace element analysis,etc.),discussed the metallogenic geology conditions,fluid properties,material sources,evolutionary characteristics and deposit genesis.According to petrography observation shows that the type of fluid inclusions in Zuoba greisen tungsten deposit includes gas-liquid phase inclusions(I),pure liquid inclusions(?)and pure vapor inclusions(?).According to micro-temperature measurement results can be seen that the homogenization temperature of fluid inclusions in Zuoba tungsten deposit is 143~447 ?;the range of salinity is 1~12.84 wt%NaCleq;the range of density is 0.63~0.96 g/cm3;the range of metallogenic pressure is 40.77~95.9 MPa;the range of depth is 4.09~10.13 km.The ore-forming fluids of the Zuoba tungsten deposit have the characteristics of medium and low temperature-medium and low salt-medium and low density,and the mineralization is mainly done in the middle and high pressuredeep-medium metallogenic environment.The gas-liquid phase composition analysis of fluid inclusions shows that the liquid composition of ore-forming fluids mainly include Cl-,SO42-,Na+,Ca2+,containing little or no NO3-;The vapor component is mainly water vapor,less of H2,CH4 and CO.The analysis results of the gas and liquid phases shows that the fluid has a multi-water mixing feature,The ore deposit process is in a weakly reduced or biodegradable environment.Geochemical analysis of rare earth elements and trace elements in ore-forming fluids shows that the total REE is relative low in deposit;the range of LREE/HREE is 0.001~4.91,average is 1.82,fractionation is not obvious;?Ce is 0.08~0.69,average is 0.48;?Eu is 0.49~2.16,average is 1.19;the Mo/W is 0.49~63.34,average is 13.57,which is reflecting the complexity of the process in Zuoba deposit;the ore-forming fluid is relative enrich of Mo,Pb,Bi,W and other elements,easily generate molybdenite?galena?bismutinite and wolframite,meanwhile,associated with Chalcopyrite,sphalerite and sphalerite etc.The Zuoba tungsten deposit has undergoes a complex evolution process(fluid mixing and cooling process),and during the mineralization process,the mixture of tungsten is in oxidizing environment,and precipitated crystallization from the fluid or along the fault zone and its dense zones on the invasion process,the tungsten elements extraction from the hydrothermal fluid in surrounding rocks,and enriched mineralization in the favorable parts of fracture and crack zones.