Mineralization Characteristics And Its Genesis From Huaqiao Gold Deposit In Dexing,Jiangxi,China

Huaqiao gold deposit,located in Dexing,Jiangxi Province,is a typical one of the biggest Jinshan gold fields in ductile shear zones of East China.Based on the subject,the application of modern metallogenic theory and test method,based on the full reading and understanding of the relevant domestic and foreign research progress,combined with the Jinshan gold mine metallogenic geological background analysis,focusing on Huaqiao gold deposit series of geology and geochemistry Characteristics,with the mineralization of metamorphic rocks of the original rock recovery and metallogenic age determined,and then explore the cause of ore deposits.The main innovations and achievements are as follows:(1)From the geochemical characteristics of Huqiao gold deposit,it can be seen that the spider diagram of mylonite,ultramafite and meta-sedimentary tuff is similar,and the total amount of element decreases with the increase of metamorphism.All kinds of rocks are enriched in Rb,Th,U,La,Ce,Nd,Zr,Hf,Sm and other large ion lithophile elements,Ba,Nb,Sr,loss of P,Ti and other high field strength elements,K elements decreased gradually with enhancing content of metamorphism,may be associated with the destruction of plagioclase.From the normalized distribution pattern of rare earth element chondrites,it can be seen that the rare earth distribution patterns of different types of rocks are very similar,showing the characteristics of right-leaning and slowing,showing the enrichment of light rare earth and weak Eu negative anomaly,indicating the participation of mantle fluid Ductile shear dynamic metamorphic process for rock metasomatic alteration.(2)The gold bearing chronology of ultramylonite,the 206Pb/238 U weighted average age was 844.5+6.4Ma,can be used to characterize the deposit(field)rock age into the rock,and at the same time as the ductile shear zone type(orogenic)gold deposit,its metallogenic and Jiangnan orogenic movement is similar,which is the main metallogenic period generally occurred in the Jinning period.(3)From the petrology,chronology,geochemical aspects of gold-bearing mylonite,ultramylonite to restore the original rock,the original rock is daciticmeta-sedimentary tuff.(4)Combined with the previous work done in Jinshan gold mine,the ore mechanism and the causes of a systematic discussion.The main factors of its ore formation are:(1)A set of marine volcanoes-sedimentary flysch formation.(2)The collision between the Huaxia plate and the Yang Zi plate caused the low green greenschist facies metamorphism in the regional formation,and formed a deep and several secondary fractures.(3)The rock is subjected to ductile shearing,which makes the rock strong dynamic metamorphism.(4)The lithosphere rises,the ore-forming fluid moves up to the ductile brittle transition zone,and the pressure is released by the "fault valve" mode,which making a series of physical and chemical conditions and leading to the enrichment and mineralization of gold deposits.