Hangjinqi Northern Ordos Basin Geological Structure And Its Significance Uranium Mineralization

The study area is Hangjinqi, located in Yimeng Uplift of Ordos Basin. In this area, the radioactivity in Zhiluo Formation of Middle Jurassic has been approved to be associated with Uranium. In addition, this phenomenon reveals a excellent propect of sandstone-type uranium. Integrating previous research achievement about this area, this paper focus on the basin geological structures and its evolution and explore the relationship to uranium mineralization. The result is expected to provide scientific guidance to sequent exploration and in-situ leaching.Integrating geology field trips, well cores, seismic profiles and other basic statistics, we did analysis about the characteristics of distributions, deformations, contact relationships in Yan’an formation, Zhiluo formation, Anding formation of Middle Jurassic and Yijinhuoluo formation of Lower Cretaceous. By the above-mentioned research, we primarily the tectonic evolution of Ordos Basin has noticeable controlled the uranium deposit, including the distebution of lithology and lithofacies, geochemical properties and enrichment et al. At present, uranium mineralization has been found out to concentrate in a low terrain area between two nose-shaped uplift striking NE-SW in the northeast of study area. This is found out to be controlled by the bottom topograghy of Zhiluo formation. For the study area, based on seismic profiles, logging, geochemical analysis and other data, we compared north area of the fault to the south, including the development and conservation of sandstone and reducing fluid environment, the above issues indicated that the fracture has controlled the thickness and buried depth of sandstone, the distribution of reducing fluid environment, which is important for uranium deposit. For reducing fluid, the unconformity between Zhiluo formation and Yan’an formation was an excellent passageway into producing formation. What’s more, the development of it also furnished favourable geological environment for Uranium deposits. The cessation of deposition of during late Jurassic During late Jurassic, the sedimentation was interrupted by the uplift of basin and the activation and migration of Uranium was so brisk. Besides, the unconformity between Jurassic and Cretaceous is over Zhiluo formation and it’s convenient for the irrigation of surface fluid, which dissolved a mess of oxidized Uranium.