摘要
The Zhaxikang zinc polymetallic deposit is located in the east of the gold-antimony polymetallic metallogenic belt of the Tethyan-Himalayan plate bar.According to deposit geology,ore bodies are mainly distributed in the nearly NS-trending tensile fractures and assume veined and lenticular forms.The ore-forming process can be divided into 2 stages and 7 sub-stages,with the main mineralization at the early stage being lead-zinc mineralization and the main mineralization at the late stage being antimony(lead)mineralization.The microscopic appraisal and electron probe analyses suggest that there are varied sorts of ore minerals,and the distribution of mineral assemblages and elements displays obvious zonation:from the depth to the shallow part(from west to east),there exists the zoning of tin(iron)-bearing sphalerite+ferromagnesian carbonate+small amounts of galena+small amounts of chalcopyrite(in depth)sphalerite+ferromagnesian carbonate+small amounts of galena+pyrite+arsenopyrite+small amounts of aftonite+small amount of quartz(medium-large depth) ※galena+sphalerite+jamesonite+ferromagnesian carbonate+boulangerite+small amounts of aftonite +quartz(middle part)※stibnite+galena+small amounts of sphalerite(shallow part)+quartz+small amounts of ferromagnesian carbonate,with the corresponding element zonation being Zn(Pb+Ag+Cu+Sn)※ Zn(Pb+Ag)※Zn+Pb(Sb+Ag)※Pb+Sb+Ag+Zn.The silver mineralization is closely related to Pb-Sb mineralizationand is mainly distributed in areas of ZK2703-ZK2302,ZK1502-ZK1105 and ZK806 which are located around theⅤore body.The silver mainly exists as isomorphism in galena,with a small amount existent in boulangerite,jamesonite,arsenopyrite,pyrite and other metal sulfides.Independent silver minerals only possess a small proportion,and they are mainly aftonite,sundtite and silver-bearing wolfsbergite.The precipitation of Pb,Zn,Sb,Ag in ore fluids was controlled by such factors as temperature,pressure,density and pH.