The Study On Fluid Inclusions And Prospecting Prediction Of Jianzhupo Lead, Zinc And Antimony Deposit, Guangxi Wuxu

Jianzhupo lead, zinc and antimony polymetallic deposit is the biggest scale and most features deposit in Wuxu ore field which located in the southeastern segment of Danchi metallogenic belt. With the main metallogenic way of filling in the field, the occurrence and shape of orebodies are strictly controlled by NNW trending faults. Orebodies are mainly steep vein. In addition, new gentle inclined stratoid orebodies have been found in this geological investigation.On the basis of geological structures, mineralization characteristics of Jianzhupo deposit in this paper, the study on fluid inclusions from No.7, No.59 main veins and new stratoid orebodies in Jianzhupo deposit have been put out, the prospecting direction and prospecting target have been put forward. The main results and cognitions are as follows:(1) The main structure of Jianzhupo ore field are NNW trend Wuxu anticline and NNW trend faults. Wuxu anticline is consisted of two sub anticlines, with "S" type turning characteristic along the axial direction; NNW trend faults, with "S" type turning characteristics along the trend direction, are the main ore-controlling structures for vein orebodies. The faults are dominately compressed with clockwise twisting before metallogenic stage while they are mainly extensed with counterclockwise twisting in metallogenic stage. Because of characteristics of tectonic movement, the structural turning position is favorable area for ore forming.(2) According to field geological observation and study of mineralography, the mineralization of Jianzhupo deposits can be divided into three stages:the first stage is pyrite-quartz stage with weak mineralization. Metal minerals are mainly pyrite with galena found occasionally. The second stage is marmatite-pyrite-stibnite-jamesonite-quartz-calcite-dolomite stage. The stage is the main metallogenic stage with a large number of dark marmatite, radial jamesonite, stibnite and a small amount of pyrite found. The third stage is quartz-calcite stage, with a small amount of stibnite, jamesonite, marmatite and pyrite and other metal minerals born in quartz-calcite veins.(3) The main types of fluid inclusions in the main metallogenic stage in Jianzhupo deposit are H2O-NaCl-CO2 type, H2O-NaCl type and pure CO2 type. The ore-forming fluids are characteristics of mesotherm, low salinity and rich CO2. For two phases H2O-NaCl type inclusions, the scope of homogeneous temperature is from 113 to 288℃, the salinity w(NaCl) is from 3.53 to 8.27%, the density is from 0.799 to 0.996 g/cm3. For H2O-NaCl-CO2 type inclusions, the homogeneous temperature is from 175 to 328℃, the salinity w(NaCl) is from 0.21 to 11.84%, the density is from 0.654 to 0.842 g/cm3. The metallogenic pressure of Jianzhupo is range from 70 to 90 MPa with depth from 1.75 to 3.77 km.(4) On the basis of temperature and salinity of ore-forming fluid, with the spatial distribution characteristics of ore-forming elements, it has been proposed that the center of Jianzhupo deposit (No.302-No.304 exploration line) is the central part for ore forming.(5) Basing on veins orebody characteristics, with intersection occurrence of conjugate joints in metallogenic stage and comprehensive judgment of metallogenic tectonic movement characteristics, it can be inferrd that ore-forming fluids of Jianzhupo deposit migrates from north to south, from deep to shallow and orebody pitches to NE side.(6) According to the study, it has been proposed that central part of the field(turning position of Wuxu anticline) and the east side of the known veins in north part of the field are prospecting targets.