| Dachang tin-polymetallic deposit ore district is located in the central part of the famous Danchi metallogenic belt in China.There are a series of large-superlarge tin polymetallic deposit in the area around Longxianggai granite body.On the basis of detailed field geological investigation,this paper focus on the metallogenic mechanism of the ore deposits in the Dachang tin-polymetallic deposit ore district.Based on the study of the geochemical characteristics of the ore and mineral elements and mineralography in the main ore deposits.The main conclusions are as follows:1.The deposits is magmatic hydrothermal mineralization characteristics in Dachang tin-polymetallic deposit ore district,the main mineralization types are: zinc copper mineralization,skarn cassiterite sulfide polymetallic mineralization,tungsten antimony mineralization.The layered zinc and copper ore body in the lower part of theTongkeng deposit is a magmatic magmatic hydrothermal filling,which is typical skarn type mineralization.2.The microscopic features of the different types of ores in the Dachang deposit ore district are basically similar.The main ore minerals in the ores are sphalerite,arsenopyrite and orpiment ore,pyrite,jamesonite,cassiterite,galena and chalcopyrite.The characteristics of symbiosis and mutual metasomatism of minerals are basically similar.3.Based on the study of element geochemistry of different types of ore deposits in the Dachang deposit ore district,the main enrichment and mineralization elements of ore deposits are As,Sn,Zn,Pb,Sb,Cu,Bi.REE characteristics of different type ore of Gaofeng deposit,Tongkeng deposit,Changpo deposit,Lame deposit are basically similar.The results showed that the concentration of light rare earth elements,as well as negative anomalies of Eu.It could be concluded that the ore deposits in the ore accumulation area have the same ore-forming fluid and source of ore-forming materials.4.LA-ICP-MS analysis of ore minerals in Dachang deposit ore district show that the elements geochemical characteristics of the same mineral in different types of ores are basically similar.The relatively high In and Fe contents in cassiterite,which jndicated to high temperature magmatic hydrothermal mineralization crystallization.Sphalerite is enriched Fe,Mn,In and depleted Ge,showing the formation and high temperature skarn type and hydrothermal type deposit related.The Co and Ni content of Pyrite,arsenopyrite and pyrrhotite is relatively low.5.In summary,combined with regional geological features of Dachang deposit ore district.It is considered that the deposits of Dachang tin-polymetallic deposit ore district is a magmatic hydrothermal deposits closely related to the yanshanian granite. |
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