Metallogenic Model And Deep Prospecting Of Jiamulong,Xiahe County Gansu Province

After nearly three years preliminary investigations,we ascertain that jiamulong gold mine in Xiahe county,Gansu province is a small and medium-sized gold mine.But a mature metallogenic model didn’t been founded.As a result,the late prospecting results were not satisfactory,especially the deep prospecting progress was slow.Through the study of the geological characteristics of the study area,this article The metallogenic model was preliminarily established,and the genesis types and prospecting criteria of the deposits were determined.This paper preliminarily established the metallogenic model,ascertained the genesis of mineral deposit types and indicator for deposit.By primary superposition halo method,we made a prospecting prediction,looking forward to provide guidance for the exploration of the same type of gold deposits in the deep,edge and metallogenic belt of mining area.The studied area locate in the western part of the western qinling orogenic belt of south China plate(grade Ⅰ tectonic units),west qinling fold belt(Ⅱ level tectonic units),passive continental margin of south qinling zone(Ⅲ level tectonic units).This area also belongs to sankonan-grignard gold metallogenic belt on the south side of the famous shake-cooperative gold metallogenic belt.The outcrop layer is mainly composed of the lower Triassic longwuhe formation and the middle Triassic guanggaishan formation in the studied area.The lithology is mainly SLATE,silty SLATE,sandstone,cuttings feldspar sandstone,etc.The tendency of fracture structure mainly consists of four groups: NWW-orientated structure,NNE-orientated structure,NNE-orientated structure,near east-west and south-north structure.Magmatic rocks are middle-acid intrusive rocks in early yanshanian period.The lithology is quartz diorite dike.According to the different structure and stratum of the ore body,the study area is divided into four ore belts.Among them,theⅠore belt and Ⅲ ore belt are the main deposit belt of gold ore bodies in the study area,accounting for about 90% of the total number of ore bodies.The main ore body ofⅠore belt is blind ore body.All the founded Stibnite body exists inⅠore belt.There are 24 gold ore bodies and 4 stibnite bodies were founded in thisⅠore belt.Among them,AuⅠ-15、AuⅠ-19、AuⅠ-20 have a relatively large size.There are 35 gold ore bodies were founded in the Ⅲ ore belt.Among them,AuⅢ-11-2、AuⅢ-12、AuⅢ-14-1 have a relatively large size.Through the research into metallogenic belt,structure,dike,surrounding rock alteration and mineralization,the characteristics of mineral symbiosis combination embedding,vein-vein interpenetration and so on in studied area,the hydrothermal process of the deposit is divided into four stage: theⅠstage,early acid reduction mineralization stage;the Ⅱ stage: Intermediate weak acid weak reducing mineralization stage;theⅢstage,late basic weak oxidation mineralization stage,epigenetic stage.By analoging characteristics of typical gold deposits in the region,with prospecting criteria in studied area,the metallogenic model of the study area was established.After that,this article hold a opinion that the metallogenic type of jiamulong gold deposit is middle-low temperature hydrothermal gold deposit after magmatic period.By using the method of primary superimposed halo and classified research into drilling primary superimposed halo samples,the sequence of primary superimposed halo axial zoning was determined as: Zn→Co→Sb→Ni→Cu→Mo→ W→Hg→As→Bi→Pb(Ⅰ ore belt);Co→Pb→Hg→Zn→As→Ni→W→Cu→Mo→ Bi→Sb(Ⅲ ore belt).By studying the variation trend of geochemical parameters,ction results of primary superimposed halos have been proved correct with bacthe predikward inference.And the ideal model of jiamulong original stacking halo was preliminarily established.It is predicted that within the range of 3250-3000 m and 2950m-2600 m,the ore vein group will appear or the ore body will have a large extension,and there will still be a blind ore body below 2500 m.Primary superimposed halo has an apparent effectiveness on forecast the depth of the blind body in the studied area.The prediction that there exists deep vein group between the elevation of 2950m-2600 m was proved right by exploration project ZK10306.