Origin of the carbonaceous debris and its implication for mineralization within the Qianjiadian uranium deposit, southern Songliao Basin

Petrogenetic Constraints of Early Cenozoic Mafic Rocks in the Southwest Songliao Basin, NE China: Implications for the Genesis of Sandstone-Hosted Qianjiadian Uranium Deposits

“…Nevertheless, the tabular U ore bodies in the Qianjiadian deposit are spatially associated with secondary reduced gray sandstones or bleached white sandstones [34] ( Figure 2) together with the widely distributed mafic rocks [17], which significantly differ from the two predominant models of redox front sandstone-hosted U deposits presented in [33]. In addition, detailed petrographic studies performed on carbonaceous debris from this deposit showed significant increase of the vitrinite reflectance, suggesting that the U mineralization is spatially associated with the alteration halo of the diabase dikes [20]. However, the emplacement age and geochemical signatures of these mafic rocks have not been carefully constrained, and their possible role in the genesis of the Qianjiadian deposit has to be clearly characterized.…”

“…Uranium ore bodies with an average grade of 0.0104% to 0.0287% are mainly tabular or lenticular in shape [42]. The ore-hosting sediments are mainly composed of fine-grained sandstone, siltstone, and mudstone with pitchblende and coffinite as the predominant uranium minerals [15][16][17][18][19][20]. Intrusive mafic rocks are also widespread in sandstones of the Yaojia Formation in the Qianjiadian area ( Figure 1c).…”

“…The Qianjiadian uranium deposit has been widely regarded as a typical interlaminar oxidation zone-type uranium deposit in the southern part of the Songliao Basin (Figure 1) [14][15][16]. Many publications have documented the sedimentary facies, depositional environment, sandstone petrography and geochemistry, mineral paragenesis and textures, mineralization geochronology, and ore genesis model for the deposit [17][18][19][20][21]. In the Qianjiadian area, uranium is mainly adsorbed or reduced on carbonaceous debris or migrated oil, and U minerals such as pitchblende and coffinite are intimately associated with iron disulphides [22][23][24][25][26][27].…”

“…[35]). (c) Spatial distribution of the interstratified oxidation and mafic rocks in the Qianjiadian uranium deposit, modified after [34] and [19]. [35]).…”

“…[35]). (c) Spatial distribution of the interstratified oxidation and mafic rocks in the Qianjiadian uranium deposit, modified after [19,34]. Moreover, the apatite and zircon fission-track data of the Baixingtu ore deposits recorded two distinct stages of rapid cooling after the Late Cretaceous, with stage I at ~80-50 Ma and stage II at Moreover, the apatite and zircon fission-track data of the Baixingtu ore deposits recorded two distinct stages of rapid cooling after the Late Cretaceous, with stage I at~80-50 Ma and stage II at 40-10 Ma, respectively [5].…”