Metallogenic Geological Characteristics And Ore-forming Regularity Of Dongguashan Copper Deposit,Tongling, Anhui Province

Abstract:Dongguashan Copper Deposit located in the center of the Lower Yangtze Geotectogene, where at the side of the northern margin of Yangtze block, and it is assigned to Middle-lower Yangtze river metallogenic belt. Based on the achievements of previous researchers, the metallogenic environment and metallogenic geological conditions, the source of the ore-forming materials, the regional metallization and the genesis of Dongguashan Copper Deposit have been discussed in this thesis by studying the field geological observation of deposit, identification of thin sections and polished blocks, the analysis of rocks and ores’geochemistry.Relied on the field geological survey of deposit, it is revealed that ore bodies lay with layered or stratiform-like structure along the shaft of Castle Peak anticiline, and formed in contact zone of magmatites and wallrocks or in the carbonate, its occurrence is consistent with the occurrence of wallrocks. Massive and disseminated structures of the ores are the most important structure, furthermore,3epochs and6stages have been divided in this research, skarn and quartz-sulfide stages are closely related with the regional metallization.According to the analysis of rocks and ores’geochemistry, the diorite, which has been formed in the phase of Yanshan, have high potassium, calc-alkaline and metaluminous characteristics and it also has a close relationship with metallization, moreover, it is recognized that rich in metallogenic elements such as Cu, Au, and primitive magma stemmed from not only mantle but also crust.In terms of the features of S and Pb isotope, it is inferred that metallogenic materials mainly acquired from magmatic rocks, which were made up of magma invaded in the phase of Yanshan. The water in Ore-forming liquid is totally from magmatic hydrothermal, little stratum water mixed in the late stage of mineralization. This Copper Deposit was formed in settings of post-collision orogenic belt, and the most important metallization is hydrothermal mineralization. The source of some metallogenic materials is the stratum, the structure contribute to invasion of the magma and offer a favorable space for orebody, while the magmatic rock provide abundant metallogenic materials, water and heat for mineralization. In one word, the deposit can be illustrated to be poly-metallic skarn deposit. On the basis of the genesis and the mineralization of Dongguashan Copper Deposit, metallogenic regularity and model also have been studied in thesis, hope to offer more adequate theoretical proof for following exploration work.