| Qixing lead-zinc-silver-gold polymetallic deposit in Boluokenu polymetallic metallogenic belt in Western Tianshan, its tectonic position in Kazakhstan-Yili northern margin active continental margin. Based on the system field investigation, using petrography, geochemistry, fluid inclusion and isotope geochemical methods, studied the metallogenic background, structure control characteristics, mineralization, ore material source and the source of the fluid. The main achievements are as follows:(1) Structure control characteristics of the mine are obviously, according to the relationship between the fracture and mineralization can be divided into mineralization and post-mineralization period fracture. The fracture of mineralization has towards mainly NNE, tendency East-South East, with tensional character, and is the transport channel of ore-bearing hydrothermal fluid, for the final place of the ore provides holding-ore space. After the ore formation, due to changes in tectonic stress field, formed fracture towards NWW, tendency North. The fracture superimposed on the fracture of mineralization, with left-lateral strike-slip nature, damaging effects on the orebody, is breaking-mine-structure.(2) Mineralization-fluid inclusions of the deposit temperature display range from150.1to237.0℃, mainly range form170.5to198.4℃; fluid salinity range from1.74to6.74%, mainly range from4.03to5.26%; fluid density range from0.83to0.93g/cm3, the average density is0.89g/cm3; mineralization pressure range from38.46to64.17MPa, mineralization depth from1.28to2.14km, the average depth is1.65km.(3) Hydrogen isotope studies show that ore-forming fluids is magmatic water mixed with atmospheric precipitation, source of sulfur is magmatic sulfur, source of lead is crust-mantle mixed source, with subduction-zone lead characteristics.(4) The wall rock of orebody-geochemistry analysis of siltstone in upperSilurian siltstone on Boluokenu mountain group show the content of rare earth elements are higher, EREE=184.08～226.98, with an average of204.36,(La/Yb) N and LREE/HREE values are7.31～8.06(average7.76) and6.59～7.07(average6.87).With obvious negative Eu anomaly, Ce anomalies are not unusual, distribution patterns the display light rare earth are relative enrichment,heavy rare earth are flat, Changes of lithophile element Rb, Ba, Sr content are relatively large, but changes of high field strength elements Sc, Zr, Nb content are small, structure background shows the active continental margin environment or island-arc environment. |
