The deposit is hosted in the Upper Cretaceous Yaojia Formation sandstone and is positioned over a depth interval between 200 and 500 m below the surface. The sedimentary period of the Yaojia Formation was the peak of the post-rift stage of the basin. The Qianjiadian area developed braided delta sediments, mainly consisting of gray, gray-white, yellow, and red medium to fine-grained lithic feldspar sandstone and feldspathic litharenite interbedded with mudstones or argillaceous siltstones. The uranium mineralization primarily occurs in medium- to fine-grained sandstones. The spatial distribution of sandstone diagenetic facies shows that during the formation of the Qianjiadian sandstone-type uranium deposit, interlayer oxidation progressed from the southwest to the northeast. Along the direction of the interlayer oxidation, red sandstones, yellow sandstones, non-mineralized gray-white sandstones, mineralized gray sandstones, and primary gray sandstones occur in succession, corresponding to a complete oxidation zone, a partial evolution zone, a weak oxidation zone, a redox transition zone, and a reduction zone, respectively.
The uranium ore bodies are mostly tabular and lenticular in shape, with an average thickness of 5.1 m. The ore–hosting sandstone generally is gray adjacent to the upper red oxidation zone. Diabase dykes also occur near the uranium deposit, and previous studies have shown that some mineralized sandstones experienced hydrothermal alteration by hydrothermal fluids related to magmatic activity, resulting in dolomitization accompanied by U migration and deposition. The average grade of the uranium ore is 0.024%, and the main uranium minerals are pitchblende and coffinite, with some brannerite. The spatial distributions of rhenium-bearing sandstones and uranium ore bodies are similar, and are located in the gray sandstone of the redox transition zone, with an average rhenium content of 447 ppb. However, the average rhenium contents of the red sandstones in the oxidation zone and the gray sandstones in the reduction zone are only 3 ppb and 6 ppb, respectively.

Uranium mineralization in mudstones of the Qianjiadian uranium deposit predominantly occurs at the upper and lower parts of mudstones in contact with sandstone-hosted uranium deposits. Cross-sectional profiles show that sandstone-hosted uranium orebodies are primarily developed in the SQK2y-EST interval, with orebodies presenting lenticular distributions within reservoir layers. Most uranium mineralization in mudstones occurs at the upper and lower part of these sandstone-mudstone contacts, consistent with the planar distribution pattern of sandstone-hosted orebodies and exhibiting lenticular or stratoid geometries. Planar maps indicate that uranium orebodies in dark mudstones adjacent to sandstone-hosted deposits often form embayed or island-like distributions, mainly concentrated in the Qian II, Qian III, Qian IV, and Qian V blocks. The SQK2y-EST interval has the widest mineralization distribution and optimal metallogenic conditions, with high-grade zones primarily located in the Qian IV area around Liujiazi, Qian II area north of Shijianfang, Qian III area in the eastern Dongsijiazi, and Qian V area south of Shenglitun. Orebodies also occur in the Qian IV area south of Baixingtu, with an average thickness of 1.15 m. Superimposition with sandstone-hosted uranium deposits shows nearly complete spatial overlap between the two.

Other Regions, Features and Areas containing this locality

References