Geochemical And Geophysical Characteristics Of The Sinongduo Ag Polymetallic Deposit,Tibet And Their Application In Targets Selecting

The Sinongduo silver polymetallic deposit in Xietongmen county,Tibet autonomous region is located in the middle of the gangdese metallogenic belt.The deposit is located in the volcanic rocks of the dianzhong formation of the linzizong group.In this paper,the silver and polymetallic ore deposits of stando are taken as the research object,and the methods and techniques such as geological survey,1:10,000rock geochemical survey and induced electric medium gradient method adopted.This paper summarizes the geological characteristics of the mining area,finds out the characteristics of geochemical and geophysical anomalies in the exploration of the mining area,defines and optimizes the prospecting target area,carries out borehole verification in the abnormal area,and finds out new industrial ore bodies.Through the research,the following results and understanding are obtained:1.The outcrop layer of the mining area is the dianzhong formation?E₁d?of linzi zong group.The present discovered cryptoexplosive breccia type pb-zn?Ag?orebody,hydrothermal vein type Pb-Zn?Ag?ore body and Ag?Pb-Zn?ore body are all produced in the volcanic rocks of dianzhong group,belonging to low-sulfide low-temperature epithermal deposit.2.The results of petrogeochemical measurements show that the abundance coefficients of As,Sb,Pb,Ag and Au are all greater than 2,indicating that the five elements are highly enriched.The results of factor analysis,correlation analysis and cluster analysis showed that the main metallogenic elements Pb,Zn and Ag had a strong correlation with Cu and Cd,while Au had a large enrichment independence,which may indicate the existence of independent gold ore bodies.With the cumulative frequency of 75%value as the abnormal lower limit,in the mining area circled?1?,?2?and?3?geochemical anomaly area,where?1?anomaly is A type of anomaly,?2?and?3?anomaly is B type of anomaly.3.There are obvious differences in physical parameters among surrounding rocks,low-grade sparsely veined Pb-Zn ores,high-grade massive Pb-Zn ores,strongly pyritized Pb-Zn ores and massive pyrite in the mining area.The polarizability is less than 2.5%,2.5%³.5%,3.5%⁷.0%,7.0%¹0.0%and more than 10%,respectively.The polarizability 2.5%can effectively distinguish surrounding rocks and mineralized bodies.Using the polarization rate of 2.5%as the lower limit of induced polarization anomaly,three geophysical anomaly zones??s1,?s2 and?s3?were circled in the mining area.Among them,?s1 and?s2 were class a anomalies and?s3 was class b anomalies.4.According to the characteristics of exploration geophysical and exploration geochemical anomalies,a total of 6 prospecting target area have been delineated.Drilling verification for geochemical prospecting target area?1?and geophysical?s2prospecting target area was carried out.Ore was found in 9 boreholes in target area of geochemical exploration.The results were remarkable.Multilayer lead-zinc ore bodies and silver-lead-zinc ore bodies were found.The average thickness of ore body is 3¹0m,the average grade of Pb+Zn is 4%,and the average grade of Ag is 28.74g/t.Three boreholes were drilled in the prospecting target area of?s2 geophysical prospecting,but the grade was low.The results show that it is effective to delineate the prospecting target area according to the petrogeochemical and induced electric medium gradient method,which can be applied to the mineral exploration of low-sulfide low-temperature hydrothermal deposits in volcanic rocks of linzizong group.