Discussion On Geological Characteristics And Genesis Of The Baiyanghe Uranium Deposit In Western Junggar

The Baiyanghe uranium deposit is the largest volcanic rock-type uranium deposit in Xinjiang,and its ore-bearing rock masses have undergone a strong post-reformation.With the help of XRF,ICP-MS and MC-ICP-MS,the petrography,this article studied the geochemistry and Nd isotopic characteristics of these ore bearing rocks mass and discussed the genesis,the tectonic setting and the relationship between ore bearing rocks mass and Baiyanghe uranium deposits.Uranium ores that are present in rock masses are also subject to strong post-reformation.In order to find out the characteristics of uranium minerals in ore,a variety of research methods such as polarized light microscopy,scanning electron microscopy,and electron probes were used to carry out detailed mineralogical studies on uranium ore,and the effects of epigenetic modifications on the mineral deposits were discussed.In order to further explore the formation and preservation of primary uranium minerals,XRD,laser Raman and carbon-sulfur analyzers were used to study the black faulted mud which is very spatially related to the primary uranium ore bodies.The research findings and conclusions are as follows:?1?The ore-bearing rock masses are formed within the intra-island tectonic setting and have undergone severe crushing and transformation after formation.The granite porphyry is characterized by alkali-rich,aluminum-rich,low-calcium,and magnesium-depleted.It is A1-type granite porphyry and is enriched in LILEs?such as K,Rb,Pb,etc.?and U,Be,and Mo Elements,also relatively enriched in Nb and Ta elements,and seriously depleted elements such as Ba,Sr,and Eu,show that they undergo a high degree of crystal differentiation during diagenetic process.The ratio of Yb/Ta is between 0.86 and 1.30,the ratio of Y/Nb is between0.35 and 0.51,and?Nd?t?is between 5.1 and 6.8.The diagram of?Nd?t?-t shows that the magma is multi-sourced.Indicating that diagenetic material may have originated from the OIB-type depleted mantle and was contaminated with paleozoic neo-crustal material.The Th/U ratio of the granite porphyry is between 2.9 and 11.6,indicating that the uranium element is leached and the ore-bearing rock mass is an important uranium source during the uranium mineralization.?2?The uranium ore which was present in the rock mass also underwent a strong crushing transformation.The uranium minerals in the ore were mainly secondary uranium minerals such as uranophane.Gangue minerals mainly include:quartz,potassium feldspar,plagioclase,biotite,fluorite,calcite,barite,etc.While the ore minerals mainly include:uranophane,gummite,uranniobite,coffinite,pitchblende,galena,pyrite,etc.The primary bituminous uranium deposits are mainly in the hydrothermal veins.The structure of the deposits includes:disintegrated structure,granite crush structure,patchy crush structure,metasomatic reaction edge structure.Near the pitchblende,some organizational features such as crustal structures and concentric ring structures remained.?3?Pitchblende was subject to fluid modification at different levels,making the mineral composition extremely complex.With the increase of the degree of fluid modification,UO2and PbO showed a decreasing trend,and the contents of Nb2O5,ZrO2,and TiO2 showed an increasing trend,indicating that the uranium was activated and transported while the fluid brought rich elements such as Nb,Zr,and Ti during the later fluid modification process.In addition,pitchblende was also relatively rich in Pb.?4?The black fault mud Raman test,which is closely related to mineralization,showed a strong carbonaceous peak.The black fault has a high organic carbon content?TOC of 0.24%to 1.07%?.It is further analyzed that the organic-rich fault mud may provide favorable conditions for the Reduction of the soluble complex of U⁶⁺to precipitate of bituminous uranium ore during mineralization.It also played a certain degree of protection after the formation of pitchblende deposits.