| The Weilasituo zinc-copper polymetallic deposit is located in the Ag-Pb-Zn-Cu-Sn-Mo metallogenic belt in the middle-south section of the Daxing'anling Mountains.Since its discovery,predecessors have done a lot of work on its geological characteristics,material sources,metallogenic regularity and genesis of the deposit,but there are differences in the study of the source of ore-forming materials,metallogenic age and types of the deposit.Because the polymetallic metallogenic belt in this area is mostly covered by quaternary,such as aeolian sand,it has great prospecting potential.Based on the present research situation,this paper discusses the genesis of the deposit from the aspects of geological characteristics,ore-forming fluid characteristics and material sources,and combines the related work of geogas survey technology to study the spatial distribution of ore-forming elements and accompanying elements in the mining area,hoping to help the exploration and research of mineral resources in the overburden area.The results show that sphalerite,chalcopyrite,pyrrhotite,arsenopyrite and pyrite are the main ore minerals in this mining area.Gangue minerals are mainly quartz,fluorite,muscovite,sericite,feldspar,calcite and clay minerals.The highest Ag content in the ore is 180×10-6.The average tastes of Cu,Zn and As are 2.13%,15.47%and 13.04%respectively.The contents of Pb,Fe,Bi,Cd,Sb,Sn,W,Rb and Co are also high,accompanied by elements such as Cr,Hg,Ni,Se,Ti and V.According to mineral assemblage,structure and intersection relationship between veins,the mineralization of the Willasituo zinc-copper polymetallic deposit can be divided into three metallogenic stages:quartz-arsenopyrite stage,quartz-polymetallic stage and quartz-carbonate stage.The study of fluid inclusion composition and hydrogen and oxygen isotopes shows that the ore-forming fluid in this area is a mixture of magmatic water and meteoric water,which has the characteristics of medium temperature,low salinity and low density.The results of sulfur and lead isotopes show that the ore-forming materials of the deposit mainly come from partial melting of the lower crust or lithospheric mantle.The deposit belongs to the magmatic-hydrothermal type.By comparing the geogas survey results of Line 15 and Line 25,the spatial distribution characteristics of Ag-As-Cu-Zn-Pb-Cd-Bi-Ni-Fe-Mn-Mo-V-W elements in the geogas have an obvious indication effect on the location of the known concealed zinc-copper polymetallic ore body,while the spatial distribution characteristics of Ti-Rb-Sb-Co-Sn-Cr-Se elements have a poor indication effect.The characteristics of rare earth elements and nano-particles in geogas and ore are consistent,which indicates that the material collected by geogas survey comes from deep concealed deposits.By studying the spatial distribution characteristics of elements in mining area,the information of deep mineralization in overburden can be reflected.Therefore,the spatial distribution characteristics of elements captured by geogas survey can be used for prospecting or geological mapping in mineral exploration of overburden areas. |
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