| Bayingobi Basin is an important Mesozoic uranium-producing basin in northern China.The main uranium deposits are of interlayer oxidation zone type.The present discovered Talignin uranium deposit occurs in the upper part of the Lower Cretaceous Bayinggobi Formation.Domestic colleges and universities and experts and scholars have carried out different degrees of research on Talignin and its surrounding areas,but therearefew studies on the restriction of genetic,mineralization characteristics,mechanism,prospecting indicators,structural-sedimentary evolution and interlayer oxidation on uranium mineralization,and lack of necessary prospecting and prediction research.Therefore,it has important guiding significance for uranium mineralization and prospecting prediction in the Tarim area.Firstly,this paper introduces the regional background of Taliu area,introduces the characteristics of regional structure,strata,magmatic rocks,uranium-bearing property and regional radioactive field halo,and discusses the regional tectonic evolution sequence.Secondly,the constraints of tectonic evolution on uranium mineralization are expounded: the double-fault depression developed in Taliu area is favorable for the development of fan delta-lacustrine deposits,and syndepositional uranium deposits are formed in the distributary Bay of fan delta;after deposition in the upper part of Bayinggebi Formation,structural inversion and strata differential uplift promote the development of interlayer uranium deposits.Through stratigraphic division and correlation,it is found that the Taliu area is the sedimentary center and subsidence center,which is consistent with the shallow seismic measurement results;through the analysis of sand dispersion system,based on the analysis of single-hole vertical sequence stratigraphy and correlation of sedimentary profiles,the fan delta-lacustrine facies sedimentary system of the upper member of the Bayinggobi Formation in Tarim area was reconstructed.Talignin target layer has primary and epigenetic rock geochemical characteristics,the latter can be divided into epigenetic reduction and epigenetic oxidation,epigenetic oxidation shows red oxidation and yellow oxidation,in organic carbon,epigenetic pyrite and other enhanced reduction ability of the formation,in the oxidation-reduction barrier near the mineralization;Inter-oxidation zone is characterized by the change of burial depth from shallow to deep from north to south,and the irregular zonal distribution in the plane is nearly east-west.The uranium mineralization in the tower lignin area is mainly controlled by sedimentary facies and interlayer oxidation zone.Sedimentary microfacies of fan delta(subaqueous)distributary channel,distributary Bay and estuary dam whose developed in upper part of Bayin Gobi formation,which is the main sandstone-type uranium mineralization occurrence horizon.The uranium elements are positively correlated with the contents of Co,Ni,Cu,Zn,Cr,Pb,Rb,Sr and Ta,and negatively correlated with the contents of Zr,V,Mo and Nb.Therefore,uranium can be used as a prospecting indicator for multielement combination.The metallogenic fluid in Taliu area formed synsedimentary uranium in mudstone construction,which formed interlayer oxidation zone sandstone uranium in grey sandstone formation outside the oxidation zone.Uranium mineralization in Taliu area is controlled by sedimentary facies,oxidation zone,structure,uranium source and provenance,reduction medium,paleoclimate and other factors.Sandstone-type uranium deposits are characterized by structural identification,lithologic lithofacies,color,petrogeochemistry,multi-element assemblage,logging.Rock and geochemistry,alteration minerals and other prospecting indicators.Based on the analysis of metallogenesis,the metallogenic geological bodies,structural planes,metallogenic structures and metallogenic indicators are defined,and the "trinity" model for prospecting and prediction in Tarim area is constructed. |
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