A Study On Metallogenic Depths Of Piaotang Quartz Vein Type Wolframite Deposits In Jiangxi Province

Piaotang tungsten deposits is located in the important nanling metallogenic beltin China,which is a typical model of "five-story" vein type tungsten deposit, and it hasan important positive significance to determine its metallogenic pressure and themetallogenic depth for other deposits on the whole area.The study,on the basis of the full analysis and synthesis of predecessors’ workand the field study and research，systematically analyse and summarize the geologicalcharacteristics, ore body characteristics of Piaotang tungsten deposits.For use of fluidinclusion geobarometer to determine the depth of mineralization has laid a solidfoundation.The study is the first to choose Beryl as the research object, And combined withthe control of other parameters,Accurate calculation the metallogenic pressure and themetallogenic depth of Piaotang tungsten deposits.Provides reliable theoretical basisfor its deep prospecting and deep prediction.,so the paper has innovativeness.The Raman spectral characteristics and temperature measurement of fluidinclusion display the most ore-forming fluid of Piaotang tungsten deposits is H2O, atthe same time the fluid also contains a small amount of CO2and CH4and so on,which shows the characteristics that the fluid comes from the deep source. The fluidsystem is mainly for the system of H2O–NaCl, In the early metallogenic stage, thereis CO2fluid in Piaotang tungsten deposits.The study of thermodynamic parameters of Inclusions in beryl for the firsttime.The uniform temperature and uniform pressure of the inclusions in Beryl arehigher, mainly for the280-400℃; the fluid salinity is low, mainly concentrated in1-2.5wt%; fluid density is mainly0.55to0.85.The system of inclusions in Beryl ismainly for the system of H2O-NaCl,so beryl formed in early fluid environment withthe high temperature and high pressure.Through measured the fluid inclusion decrepitation temperature and combination with stable isotope geological thermometer of Beryl and quartz.it can be known thatthe mineralization temperature in the main ore-forming stage of tungsten and tin inPiaotang tungsten deposits is330-400℃.Through combined with the isometric chartof beryl and the main formation temperature,drawing P-T joint phase diagram of thesymbiotic partial immiscible H2O-NaCl inclusions and CO2–H2O-(NaCl) inclusions,using the isochore crossing method, it can be seen that the pressure range in the mainore-forming stage of Piaotang tungsten deposits is:105-159MPa.According to the geological reconstruction method and the metallogenic depth-pressure estimation,For the first time to estimate the metallogenic depth of Piaotangtungsten deposits.Studies have shown that the reasonable metallogenic depth range ofPiaotang quartz vein type wolframite deposits is:3.5to5.9km.