Discussion on geological characteristics and prospecting direction of sandstone-type uranium deposits in Chaoshui basin
s:Chaoshui basin is one of the Mesozoic-Cenozoic basins where sandstone-type uranium mineralization are developed in northern China.It is located in the Alashan block of the North China plate.The characteristics of lithology-lithofacies,sand bodies epigenetic oxidation and typical occurrences in the target layer are summarized and the prospecting direction of the basin is proposed.The Lower Cretaceous Miaogou group and the Middle Jurassic Qingtujing formation were regared as the main uranium-producing horizons in Chaoshui basin and also the target horizons for prospecting.The target horizons developed fan delta and braided river facies,and the sand bodies are large,and has favorable conditions such as litholoy-lithofacies and sand bodies for the formation of sandstone-tyoe uranium deposits.Uranium is closely related to geochemical environmental parameters such as ∑S,Corg and valence iron.The epigenetic transformation is very favorable for the superposition and enrichment of uranium mineralization.After the formation of the target horizon,multi-stage uplift and tilt transformation occurred,and sandstone-type uranium mineralization was formed near the bottom of the phreatic oxidation zone and the front line of the interlayer oxidation zone.Through comprehensive analysis,it was pointed out that the prospecting direction of the Lower Cretaceous Miaogou group variegated layer is of relatively stable and moderately uplifted monoclinic structure,long-term uplifted uranium-rich granite body periphery,carbon-rich gray layer in the red formation.Fan delta facies sand body and phreatic oxidation superposition site,and the prospecting type is sedimentary diagenetic superimposed phreatic oxidation zone type uranium deposits;The prospecting direction of the Middle Jurassic Qingtujing formation is the wide and gentle structural slope zone,uranium-rich geological body,coal-bearing braided river facies gray sand body and interlayer oxidation epigenetic transformation site,mainly to find interlayer oxidation zone type uranium deposits.
Chaoshui basinlithology-lithofaciessand bodiesepigenetic oxidationprospecting direction
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