Geochemical Exploration Model Of Silver Deposits In The Southern Segment Of Great Xing'an Range

The southern segment of Great Xing'an Range is one of the most important ore-concentrated area of silver in China.In recent years,with the discovery of several large and super-large silver deposits and the delineation of a large number of geophysical-geochemical anomalies around them,the area shows great prospecting potential.Three representative silver deposits which include Shuangjianzishan,Bairendaba and Mengentaolegai are selected as typical deposits to study their geological and geochemical characteristics,and finally establish geochemical exploration model of silver deposits in the southern segment of Great Xing'an Range by compiled analysis.The host strata of shuangjianzishan silver deposit are middle Permian dasizhai formation.Mineralization is closely related to hidden granitic intrusions in the ore area.The ore-controlling characteristics of multi-stage faults are obvious.The main form of ore body is vein,bedded and lens.The main types of the wall rock alteration include quartzitification,chloritization,sericitization,pyritization,and carbonatization.Prospecting indicator elements in the stage of regional geochemical exploration include Ag,As,Bi,Pb,Sb,Sn,W,7 items.Prospecting indicator elements in the stage of petrogeochemical exploration include Ag,As,Au,Cd,Cu,Mo,Pb,Sb,Sn,Zn,10 items.Universal prospecting indicator elements include Ag,As,Cu,Mo,Pb,Sb,Sn,Zn,8 items.The host rock of Bairendaba silver deposit is the xilinhaote complex of the lower proterozoic baoyintu formation and the quartz diorite of the Variscan period.The near east-west fault is the main ore-controlling structure.The main form of ore body is vein,vein-like,lens and bedded.The main types of the wall rock alteration include quartzitification,clayzation,fluoritization,sericitization,and chloritization.Prospecting indicator elements in the stage of regional geochemical exploration include Ag,As,B,Be,Cd,Cu,Li,Sb,Sn,Y,Zn,11 items.Prospecting indicator elements in the stage of petrogeochemical exploration include Ag,As,Au,Bi,Cu,Pb,Sb,Zn,8 items.Universal prospecting indicator elements include Ag,As,B,Cd,Cu,Pb,Sb,Zn,8 items.The Mengentaolegai silver deposit is located in the center of the Mengentaolegai granite base.The ore-controlling fault is the early east-west fault.The main form of ore body is vein and mesh-vein.The main types of the wall rock alteration include sericitization,quartzitification,chloritization and barringeritization.Prospecting indicator elements in the stage of regional geochemical exploration include Ag,Bi,Pb,Zn,Cd,Be,6 items.Prospecting indicator elements in the stage of petrogeochemical exploration include Ag,As,Au,Cd,Cu,Mo,Pb,Sn,Zn,9 items.Universal prospecting indicator elements include Ag,Be,Bi,Cd,Pb,Zn,6 items.The silver deposit in the southern segment of Great Xing'an Range is dominated by hydrothermal vein type deposit.The ore-controlling characteristics of faults are obvious.Mineralization is often associated with hidden plutonic intrusions.The main form of ore body is vein,bedded and lens.The main types of the wall rock alteration are low and medium temperature hydrothermal alteration.Most silver deposits were formed during the yanshanian period.There are six universal prospecting indicator elements which include Ag,As,Cd,Cu,Pb,Zn,for silver deposits in the southern segment of Great Xing'an Range.It can be used as a guide to delineate the prospecting target and find similar deposits.