Preliminary Study On Application Of Geogas And Soil Geochemical Survey For Concealed Ore Body In Gejiu Sn-Cu Polymetallic Ore Field

Yunnan Gejiu Sn-Cu polymetallic ore field is located at the western edge of the Youjiang fold belt on the western most side of the South China Block.It is an impor-tant part of the tin polymetallic metallogenic belt in southeastern Yunnan.From north to south,it can be divided into Malage,Songshujiao,Gaosong,Laochang,and Kafang ore fields.Based on previous studies,this paper took the area east of Gejiu fault as the research object,carried out soil geochemical survey and geogas survey,compared the abnormal characteristics of soil and geogas in concealed ore deposits,and indicated the prediction of concealed ore deposits.Mainly achieved the following results:1.By analyzing the distribution and combination characteristics of 12 elements in the soil,it can be judged that Sn-Cu is the most important mineralization element combination,Pb-Zn-W is the less important mineralization element combination,and Ag-As-Sb-Cd-Mo.etc is an element combination that has a certain genetic relationship with the mineralization elements in the study area.2.The anomalous parts of each soil profile fit well with the spatial position of the deposit;the anomalous constituent elements of the profile passing through different deposits are also slightly different.We can see a clear Cu-Sb-B soil combination anomaly above the Songshujiao Sn-Pb deposit,a clear Sn-Mo-Sb soil combination anomaly above the Gaosong Sn-Pb-Zn deposit,and the Laochang Sn-W-Cu deposit and Kafang Cu(Au)-Sn deposit show broad and clear soil Sn anomaly;3.The soil sample has inheritance to the ore body in the combination of indicator elements,and has certain indication to the hidden ore body in the soil cover area.4.The geogas anomalies such as CO2 and SO2 above the ore body reflect the fault structure well.Through analyzing the data,it is found that the geogas measurem-ent method has a certain guiding role in the search for sulfide deposits related to fault ore control.