Studying On Geological And Geochemical Characteristics Of Uranium Ore From Typical Uranium Deposits In Zhuguang Area

In this thesis,the mineral composition and geochemical characteristics of uranium ore in three typical uranium deposits covered 361 deposit,Mianhuakeng deposit and Lanhe deposit in Zhuguang area,northern Guangdong province was studied and compared.With the results and understanding of tracing mineral sources of former,the sources and fluid properties of uranium ore-forming fluids and the possible ways of uranium precipitation and enrichment was discussed.The following new views and understandings was concluded by this thesis:1)The three ore deposits from different regions in Zhuguang area have similar uranium metallogenic characteristics,uranium ore types,and ore mineral compositions.2)During the mineralization of uranium ore,new gangue minerals mainly include microcrystalline quartz,fluorite,carbonate minerals,pyrite,etc.Pyrite and uranium minerals are distributed in microcrystalline quartz,fluorite,carbonate with their own independent forms or internal,or interspersed with each other in ore-forming neonatal gangue minerals.This indicates that they are all the products that the same period and source of ore-forming fluids precipitated,and the ore-forming fluid composition is characterized by rich mineralizers such as F,S,and C.3)The study considers that these are great different between the geochemical composition of uranium ore elements and surrounding granites,and between the geochemical composition of uranium ore elements and diabase is relatively similar.The trace elements of uranium ore in the three ore deposits all show a significant increasement of the content of heavy rare earth elements,relatively decrease in LREE/HREE ratio,andgreat reduction in the Eu loss.The loss of uranium is between the granite and the diabite.The bead network pattern shows the“Ba-Th”valley and the“Nb-Ta”valley character.In conclusion,the metallogenic fluid may have the involvement of mantle source material.4)The C and S isotopes of the ore-forming periods indicate that the ore-forming material sources of the three deposits have similar source area properties,and the ore-forming fluids have the characteristics of mantle source properties.5)It is considered that changes in physicochemical conditions such as decompression,temperature drop,and solubility(saturation)may be the main factors restricting the precipitation of uranium crystals and enrichment of ores in granite-related hydrothermal uranium ore fluids,and have nothing to do with the redox effect.