Experimental Study On Deep-penetration Geochemistry In Huanniushan Pb-Zn-Ag Deposit,Gansu Province

Huanniushan lead-zinc-silver deposit is located in Huanniushan area of Beishan,Gansu Province.It is a typical arid Gobi desert landscape.Due to the influence of eolian sand,it is difficult for traditional geochemical exploration methods to obtain mineralization information under the overburden.In this paper,the penetrating geochemical method test is carried out in the mining area to verify the indication effect of geo-gas survey on deep orebodies,and to explore the source and material form of anomalies.The geochemical study of the deposit provides an abnormal interpretation basis for penetrating geochemical survey,so this paper includes three parts: mineralogical characteristics of the deposit,genetic analysis of the deposit and penetrating geochemical test.The mineralogical characteristics of the deposit were studied by microscopic observation and Electron Microprobe analysis.the mineral composition of the ore,the characteristics of metal sulfides and the occurrence of silver were studied.The main metal minerals of Huanniushan lead-zinc-silver deposit are pyrite,pyrrhotite,galena,sphalerite and so on.The analysis of ore elements shows that Pb,Zn and Ag are dominant,accompanied by Au,Sb,Cd,Bi and other elements.Silver in mining area is divided into visible silver and invisible silver.it can be seen that silver is two kinds of independent silver minerals containing antimony,swarf antimony silver ore and sulfur antimony copper silver ore.invisible silver mainly occurs in galena,chalcopyrite and other minerals in the form of isomorphism.A small amount of arsenopyrite exists in the lattice of minerals such as arsenopyrite and pyrite.Genetic analysis of the deposit by testing five kinds of single minerals S and Pb isotopes in the ore to explore the source of metallogenic materials,combined with previous research data to analyze the genesis of the deposit.Sulfur isotopes are distributed in a bimodal manner and the degree of sulfur homogenization in the ore is low,indicating that the source of sulfur in the ore is not unique,including magmatic hydrothermal solution and stratigraphic sulfur mixing.Lead isotope diagrams show that magmatism plays an important role in mineralization,and the ore lead comes from both upper crustal components and deep source materials.It is considered that Huanniushan lead-zinc-silver deposit experienced Ordovician submarine jet deposition to enrich a large number of ore-forming materials,and the ore-forming elements in Triassic magmatism activated strata were finally mineralized.The penetrating geochemical geogas survey test was carried out between the third and fourth ore belts in Huanniushan lead-Zinc-Silver Mine area.the results show that the abnormal contrast of metallogenic elements is about 3,and the geo-gas is homologous to the soil anomaly.The geo-gas anomalies of the main metallogenic elements Pb and Zn are obvious,and the anomalies correspond well to the lower orebodies.The geo-gas anomaly element assemblage Pb-Zn-Fe-Cu-Sb-Cd-Ni-Ti,can be used as an indicator element of concealed lead-zinc orebodies in the Gobi covered area of arid wasteland.Compared with the characteristics of rare earth elements in geo-gas,ore and granite in mining area,the characteristics of rare earth elements in geo-gas and ore samples have good consistency.The assemblage of abnormal elements of ground and gas is consistent with the assemblage of metallogenic elements in mining area,which indicates that there is an inheritance relationship between the anomaly of ground and gas and the deep orebody.The morphology,structure and element composition of nanoparticles in three different media,such as geo-gas,soil and ore,were observed.it was found that the morphology and element assemblage of nanoparticles in the three media were consistent,all of which were related to deep mineralization.Nano-metal particles are the form of geo-gas abnormal materials.Geo-gas measurement can capture and detect nano-metal particles to achieve the purpose of predicting deep mineralized bodies.