Enrichment Of Rare Elements In Huayuan Ore Field In Western Hubei-western Hunan Lead-zinc Metallogenic Belt And Metallogenic Dynamics Background

The western Hubei and western Hunan lead-zinc metallogenic belt is located in the middle of the Yangtze block.It is one of the 20 important lead-zinc metallogenic belts in China.Numerous lead-zinc deposits have been discovered in the metallogenic belt.Huayuan ore field is the most representative lead-zinc ore field in the lead-zinc polymetallic metallogenic belt of western Hubei and western Hunan.The predecessors have done a lot of research in the study area,and achieved some results.However,at present,the research on the mineralization of scattered elements in Huayuan Pb-Zn ore field is still weak,and the understanding of its metallogenic potential is insufficient.There is still some controversy on the main carrier of scattered elements,and the substitution mechanism of scattered elements into sulfide has not been involved.The study of genesis and regional metallogenic dynamics background of the deposit is less involved,and further research is needed.This paper will study the above problems,and the results and understanding are as follows:The Fe content of sphalerite in the Huayuan lead-zinc ore field is not high,far less than the Fe content in ferrosphalerite,which is not a ferrosphalerite.Dispersed elements Cd,Ge and Ga are relatively enriched,in which Cd enrichment is the highest,Ge enrichment is relatively high,and Ga enrichment is low,and the contents of In,Tl and Se are low.Zn²⁺?(Fe²⁺,Cd²⁺)is directly replaced by Fe and Cd in sphalerite in the form of+2 valence,The replacement of dispersed element Ge is mainly 3Zn²⁺?Ge⁴⁺+2Cu⁺,Fe and Ge have the substitution relationship of 4Zn²⁺?Ge⁴⁺+2Fe²⁺+?(crystal vacancy),the dispersed element Ga has the substitution relationship of5Zn²⁺?2Fe²⁺+2Ga³⁺.According to the ratio of sphalerite elements in the ore field and the composition of sphalerite trace elements,the metallogenic temperature is 80??200?(concentrated in 100??180?,with an average of 133?),which is consistent with the previous fluid inclusion data,indicating that the ore-forming fluid of the deposit is medium-low temperature basin fluid.The variation range of sulfur isotope content in the mining area is large,and it has the characteristics of enriching heavy sulfur.The?³⁴S values of the same sulfides have no obvious difference,and the sulfur isotope of sulfides has no obvious tower effect.Sulfur isotope fractionation in the mining area is basically balanced.According to the sulfur isotope content,the ore-forming temperature of the lead-zinc deposit in the mining area,and the characteristics of asphalt and carbon organic matter in the mining area,it can be inferred that the reduction of sulfate is mainly related to the thermochemical sulfate reduction(TSR)of organic matter.According to the Pb isotopic structure pattern of sulfide ore in the mining area,it can be seen that the ore lead originates from the mixed source of orogenic belt and upper crust.Based on the geological survey of the mining area,the enrichment regularity of trace elements in sphalerite,the metallogenic temperature of the deposit and the characteristics of According to the Pb isotopic structure pattern of sulfide ore in the mining area,it can be seen that the ore lead originates from the mixed source of orogenic belt and upper crust.Based on the geological survey of the mining area,the enrichment regularity of trace elements in sphalerite,the metallogenic temperature of the deposit and the characteristics of Ga+Ge?In+Se+Te?Ag triangle diagram,it can be inferred that a series of lead-zinc deposits in the lead-zinc mining area of western Hubei and western Hunan should belong to the epigenetic low temperature hydrothermal deposit,and the typical Mississippi Valley type lead-zinc deposit(MVT lead-zinc deposit).The lead-zinc metallogenic belt in western Hubei and western Hunan experienced an inland orogenic process in South China in the early Paleozoic.According to previous studies on the evolution history of regional tectonics and the metallogenic epoch obtained.This paper suggests that the Huayuan Pb-Zn ore field was formed under the dynamic background of forming various favorable ore-controlling structures and triggering the migration and deposition of ore-forming fluids in the early Paleozoic inland orogenic belt in South China.