The uplift and denudation history of the orogenic belt and the basin–mountain coupling process have directly or indirectly affected the generation, scale, and preservation of sandstone-type uranium deposits in the eastern Junggar Basin by controlling the uranium source, lithology, facies, hydrogeology, post-generation modification, and other mineralization conditions. Taking the eastern Junggar Basin as the research area, this study proposes the constraints on sandstone-type uranium deposits by the tectonic uplift and denudation history of the orogenic belt in the basin using the apatite fission track (AFT), detrital zircon geochronology, and other methods. The results of the AFT age test and thermal path simulation indicate that the orogenic belt in the eastern Junggar Basin underwent four rapid uplifts; (from approximately 300 Ma to approximately 250 Ma, from approximately 130 Ma to approximately 90 Ma, from approximately 65 Ma to approximately 30 Ma, and from approximately 20 Ma to 0 Ma). Moreover, the timing of the uplift has a spatial trend of gradually becoming younger from south to north. The detrital zircon U-Pb age test showed that the sediment source area of the basin is mainly distributed in three age intervals, i.e., 460–390, 360–270, and 190–170 Ma. The comprehensive evaluation of the clastic sediment composition, stratigraphic distribution of the erosion source area, and thermal history showed that a large amount of exposed Carboniferous–Permian granites in the Qinglidi and Karameri Mountain erosion source areas contributed dominant sediment material and uranium sources for the Triassic and Middle and Lower Jurassic strata in the basin. The Ordovician–Early Devonian granites only provided sediment sources for the Upper Triassic and Lower Jurassic strata in the basin. Altay Mountain contributed some sediment sources for the Middle and Upper Jurassic strata after the magmatic activity and rapid uplift occurred in the Middle Jurassic. Based on the comprehensive analysis of the influence of the tectonic uplift process of the orogenic belt and the transformation of material source areas on uranium mineralization, the granites in the erosion source areas are proposed to contribute both external and internal uranium sources for uranium mineralization. Uranium mineralization mainly occurred in the tectonic retreat period after the rapid uplifts of the Cretaceous and Paleogene. It was terminated by the intensive uplift-induced stratigraphic deformation in the Miocene.

The Qianjiadian (QJD) uranium ore field, located in the southwest of the Songliao Basin of east China, was discovered within the red-variegated depositional layer of the Upper Cretaceous Yaojia Formation (Fm). It preformed some particular and complex characteristics in respect of the occurrence location, ore-hosting strata, alteration, and morphology of the ore body, compared with the sedimentary uranium deposit generated in the traditional dark coal-bearing clastic strata. In this study, the categories of organic matter (OM) within the Lower Member of Yaojia Fm (LYF), and their effects on the rock alteration and uranium mineralization process, were researched macro-microscopically. The aim of the study was to confirm the co-associated relationships between the gray layer, rock-faded zone, and tabular-shaped ore body, in addition to their genesis. Results showed that the OM mainly consists of synsedimentary carbonaceous detritus (kind-I), amorphous movable humic substances (kind-II), and deep-originated hydrocarbon fluid (kind-III), which widely led to rock-bleaching, green alteration, and different forms of pyritization and carbonation throughout the geological history. OMs of kind-I and kind-II were inherited from terrigenous higher plants, and did not directly adsorb and bio-reduce hexavalent uranyl ions during the metabolic processes of sulfate reducing bacteria (SRB), but indirectly promoted uranium precipitation related to a H₂S-rich secondary reducing barrier, produced by bacterial sulfate reduction (BSR) and the pyrolysis of the diabase dikes. III-OM was derived from deep reservoirs and exhibited multiple positive effects of increasing the reduction capacity of the primary weak reducing strata, and protecting and enriching the earlier ores. Uranium in the ores is mainly composed of pitchblende, followed by a small amount of coffinites and uranium-bearing titanium minerals. Combined with the geological setting of the QJD ore field, a six-stage ore-forming model for the LYF was constructed from the perspective of the reducing medium, i.e., (1) development of ore-bearing sand-bodies in the Yaojia Fm period; (2) formation of a tabular grey layer before the Nenjing Fm period; (3) initial bleaching and uranium pre-concentration during the diagenetic period; (4) initial mineralization and hydrocarbon reduction from the end of the Nenjing period to the end of the Mingshui period; (5) main mineralization and thermal transformation in the Paleogene period; and (6) superimposed mineralization in the Neogene period. The proposed new model does not enrich the uranium metallogenic mechanism for the red-variegated bed, but plays a key role in guiding the uranium prospecting for similar red beds, both in the Songliao Basin and in other sedimentary basins globally.

Kaolinite is a common mineral found in most Chinese sandstone-hosted uranium deposits. It occurs particularly in coal-bearing clastic rocks in northwest China, such as the uranium deposits in the Yili Basin, which is well known for hosting several large-scale roll-front uranium deposits. Previous studies have provided limited information on the origin of kaolinization and its role in the uranium mineralization. This study uses gas hydrocarbon, fluid inclusions, O and H isotope analysis, and scanning electron microscopy observations to investigate the formation of kaolinite in ore-hosting rocks from the Mengqiguer uranium deposit in the southern margin of the Yili Basin and to determine its role in the uranium mineralization. Results suggest that kaolinization is intense in the coal- and ore-bearing clastic rocks and that it is related to leaching of feldspar by acidic fluids. Vermicular kaolinite was formed by hydrocarbon-bearing fluid generated from coal and carbonaceous mudstone during a shallow-burial diagenetic stage at low homogenization temperatures ranging from 69 to 78°C and at relatively high salinities of 7.6−11.0 wt% NaCleq. Consequently, silicate minerals (such as feldspar) were leached and created secondary pores that hosted the subsequently formed uranium minerals. In contrast, micritic kaolinite was formed by infiltration of meteoric fluid enriched in U and O₂ at low homogenization temperatures of 51−63°C and low salinities of 1.2−3.7 wt% NaCleq. U⁶⁺ was sorbed by the micritic kaolinite through cation exchange, forming a U-bearing kaolinite complex; it was also reduced by pyrite and carbon detrital, thereby precipitating at the acidic oxidation front. The results of this study confirm that intense kaolinization is closely related to uranium mineralization in coal-bearing clastic rocks.