The early surface uranium mineralization zone discovered in the Saierhaina area of Yin'e Basin was initially believed to be sandstone-type formed by groundwater or interlayer oxidation.This study revealed the ore host rocks are dolomitic phosphatic rock and phosphatic siltstone.The ores contain a large amount of microcrystalline apatite(francolite)which was identified as carbon-fluorine apatite by electron probe and laser ablation techniques and occured as microcrystalline aggregates(＜1μm)in form.Whole-rock major and trace element analysis showed a good positive correlation between uranium content and P,Ca content,while the in-situ analysis(LA-ICP-MS)of apatite indicated a positive correlation between uranium content and P,Ca,REE,and other elements.No uranium minerals were found through high-resolution scanning electron microscope,indicatting that uranium is incorporated into apatite in the form of solid solution.Lithology and lithofacies,in-situ trace element composition and rare earth element characteristics of apatite and genesis of associated minerals showed that the uranium-rich apatite was formed during the diagenesis process under the influence of microbial activity.Therefore,the uranium exploration in Saierhaina area should pay attention to the mineralization of both phreatic-interlayer oxidation and sedimentary diagenesis.
国家科技期刊平台
NSTL
维普
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