| The Ke Yue lead polymetallic mining area studied in this paper is located in the south of Tibet,northwest of Longzi County,about 40 kilometers away from the same county.Between the Indus Yarlung Zangbo River Suture Zone?YZSZ?and the high Himalayan basement complex zone,it crosses the Himalaya massif and borders the Gangdise terrane in the North.The regional strata belong to Himalayan stratigraphic area and Kangma Longzi stratigraphic division.The area has experienced a long-term tectonic sedimentary magmatic evolution process,belonging to the Tethys Himalayan structural domain,developed with fold structure and fault structure.In addition,there are large-scale and widely distributed southern Tibet detachment system,rift system and dome belt.Ke Yue lead polymetallic deposit is a typical type of lead polymetallic deposit in the antimony gold polymetallic metallogenic belt of southern Tibet.Its prospective resources can reach large scale.However,the level of research on the deposit is low and the genesis of the deposit is controversial,which restricts the next exploration work.Therefore,on the basis of previous studies,this paper tries to study the macroscopic geological characteristics of Ke Yue deposit,according to the ore fabric and mineral assemblage characteristics,mainly combined with the optical thin section under the microscope,to carry out the research on the relevant characteristics of the common and representative ores in different ore bodies,focusing on the analysis of their mineralogical characteristics,mastering the mutual relationship and generation order of minerals,so as to judge the mineralization period.At the same time,it will provide more abundant mineralogical data for the follow-up analysis and study of the genesis of Ke Yue lead polymetallic deposit,thus providing theoretical basis for the induction of the main ore controlling factors and ore prospecting indicators of the deposit,so as to ensure that the excavation and exploration of the same type of deposit can be carried out more smoothly and efficiently.The ore-rich stratum of Ke Yue deposit is mainly the lower Jurassic ridang formation?J1r?.The lithology of the stratum is gray black slate,shale and quartz sandstone,and the boundary between the ore body and surrounding rock is clear.The No.1 and No.2 orebodies of Ke Yue deposit are vein,lenticular and bedlike.They occur in F1 fault and are strictly controlled by it.The orebodies extend continuously along strike and trend.The wall rock alteration in the mining area mainly includes:silicification,siderite-rhodochrosite mineralization,pyritization,limonitization,carbonation and some chloritization,sericitization and clayization.Through the observation and identification of indoor microscope,the ore types are mainly massive ore,breccia ore,crystal cave ore,disseminated ore,strip ore,vein ore,etc.;the ore structure is self-shaped semi-self-shaped granular structure,heteromorphic granular structure,metasomatic residual structure,colloidal structure,etching structure,reaction edge structure,emulsion drop structure,etc.;the ore structure is fine Vein net vein,massive,breccia,lamellar and crystalloid structure;ore minerals mainly include galena,sphalerite,pyrite,jamesonite,stibnite,arsenopyrite,chalcopyrite,siderite,stibnhua,lead vanadium,etc.According to the relationship and combination of minerals,it can be divided into three metallogenic periods,i.e.sedimentary period,meso low temperature hydrothermal metallogenic period and supergene period.The typomorphic characteristics of galena and pyrite show that the formation of the deposit is related to the hydrothermal process of middle and low temperature,sedimentation or sedimentary transformation.The ore-forming process undergoes the superimposed transformation of sedimentation and later hydrothermal,and the ore bearing strata may provide some ore-forming materials.The strata in the Ke Yue deposit contribute a lot to sulfur,and the ore lead source is characterized by the upper crust lead,which mainly comes from the Himalayan crystalline basement.It is concluded that the genesis of the multi-stage superimposed mineralization of the Ke Yue deposit is a hypabyssal ultrahypabyssal medium low temperature hydrothermal vein lead polymetallic deposit mainly filled with ore-forming materials. |
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