鄂尔多斯盆地泾川铀矿含矿层黏土矿物特征及其成因研究OA

[Objectives]The Jingchuan uranium deposit,located on the southwestern margin of the Ordos Basin,is a newly discovered sandstone-type uranium deposit in recent years.Studying the composition,distribution,and genesis of clay minerals in the ore-bearing layer is of great significance for understanding the properties of ore-forming fluids and the mechanism of uranium enrichment.[Methods]In this study,systematic core samples were collected from the ore-bearing Lower Cretaceous Luohe Formation of the Jingchuan uranium deposit.Multiple analytical techniques were employed,including thin-section identification,visible and near-infrared to shortwave infrared(VNIR)spectroscopy,X-ray diffraction(XRD),and scanning electron microscopy with energy-dispersive spectroscopy(SEM-EDS).These methods were used to investigate the macroscopic distribution and microscopic occurrence characteristics of clay minerals in the Luohe Formation and to explore their relationship with uranium mineralization.[Results]The results indicate that the clay minerals in the ore-bearing layer are dominated by smectite(S),illite(I),and illite/smectite mixed-layer(I/S),with minor amounts of kaolinite(K)and chlorite(C).Overall,these minerals reflect primary sedimentary characteristics with weak late-stage alteration.Variations in clay mineral composition were observed among sandstones of different colors.Kaolinite content is higher in grey sandstone and shows a positive correlation with uranium content.[Conclusion]This study reveals the composition and distribution characteristics of clay minerals in the ore-bearing layer and their genetic relationship with uranium mineralization.It provides a scientific basis for further research on the mineralization mechanism and exploration forecasting of this type of uranium deposit.