The implication of six kinds of new sandstone-type uranium deposits to uranium resources potential in North China

Abstract：Through ten years’ effort, six kinds of new large and superlarge sandstone-type uranium deposits have been found and explored in Mesozoic-Cenozoic sedimentary basins within North China, which are named temporarily as Yili pattern, Turpan-Harmi pattern, Dongsheng pattern, Ulanchap pattern, Manite pattern and Tongliao pattern. They occur in sedimentary basins of different tectonic settings and are different in deposit geology, ore body geology and controlling factors., but they have some common basic characteristics in metallogenic evolution. In Yili pattern and Turpan-Harmi pattern, mineralization is of typical interlayer redox feature; nevertheless, the former pattern is characterized by uranium superimposition and enrichment under the condition of whole uplift of monocline or different uplifting and falling conditions of ore-bearring strata, whereas the latter pattern is characterized by mineralized zonation on the southern and northern sides of the fault superimposed on the structural slope and small anticline structure under tectonic uplifting. In Dongsheng pattern, mineralizaton is mostly dominated by paleo-interlayer oxidation zone modified by later reduction; in Ulanchap pattern, mineralization is closely related to the evolution of lake flooding events; In Manite pattern, mineralization is of paleovalley type formed by alternation between phreatic redox and interlayer redox; in Tongliao pattern, mineralization is controlled by “tectonic window, fault and reducing matters in the deep part”, and is also probably related to dikes of basic rock (heat source). In the above six patterns , a rule may occur in their rock assemblage from west to east. The west three pattern are controlled by Upper and Middle Jurassic coal-bearing clastic rocks, while the east three patterns are controlled by Lower Cretaceous argillaceous sandstone and fine sandstone. It is indicated that the discovery and exploration of the six new kinds of sandstone-type uranium deposits not only strengthen insurable capability of uranium resources in China but also indicate the orientation and deploy for uranium resources potential evaluation and prospecting in the future.