Geochemistry Characteristics And Relationship With Uranium Deposite Of Zhuguang Mountain And Guidong Region

The researches of mafic dykes in Zhu Guangshan, Gui Dong area has been last for half a century, formal researchers did a huge number of works of this area. Researchers make deep researches of rock masses in different regions, however, researchers of mafic dykes and its relationships between uranium deposit is scanty. This article is going on to study with hornblende diabase at Zhu Guangshan, Gui Dong area, thus trying to discuss relationships of deposit formation between mafic dykes and uranium deposit. The approach of this thesis is based on the facieology, major and minor geochemistry of element and geochemistry of isotope and 40Ar-39 Ar chronology. Zhu Guangshan, Gui Dong area hornblende diabase has higher in Al₂O₃（12.53%¹4.59%） and lower in Na₂O（2.45%³.41%）,K₂O（0.41%⁰.93%）,Ti O₂（2.15%³.17%）,Si O₂（48.72%⁵1.20%）. All samples Na₂O>K₂O（2.63%⁶.41%）, enrich of LILE（Rb,Th,U,K）, content of Cr and Ni are lower than the reference value of original basaltic lave obviously. Volume dose of REE is higher（172.40ppm²21.51ppm）,LREE is slightly enrichment（LREE/HREE=0.71¹.87%）,none abnormal of Eu（δEu=0.93 1.07）, and higher number of εNd（t）（-0.93 4.90）,（87Sr/86Sr）i（0.70524⁰.71139） and abnormal Dupal Pb. In the diagram of Nd-Sr and Nd-Pb isotope chart, the hornblende diabase has feature of original mantle area in DMM, EMI and EMII. The formation of this feature is not because rising mantle lave mixing with crust material but because of subduction belt fluid metasomatic upside mantle wedge. The theory of formation of Zhu Guangshan, Gui Dong area hornblende diabase of later period of early Cretaceous to middle Jurassic is because the structural environment of crust extend and lithosphere reduction, and because of enrichment mantle original which has DMM, ENI and EMII mantle end member mixture liquation.Zhu Guangshan, Gui Dong area hornblende diabase has closely connection with uranium deposit. In the time domain, age of mafic dykes are older than mineral and younger than rock masses, coincide with four times of plate tension event in Hua Nan area. In the space domain, it generally form rich ore at intersection area of mafic dykes, quartz vain and altered granite, but uranium is mainly supported by rock masses, small part supported by mafic dykes. But mafic dykes break channel for ore-bearing hydrothermal and provide advantages for ore-bearing hydrothermal sediment. Bes ides, mafic dykes has a huge number of reducing agent and reducing environment to provide advantages for reduction action of uranium ion of ore-bearing hydrothermal thus accelerate its sediment.