隆起对砂岩型铀矿成矿的控制及找矿启示

沉积盆地古隆起对油气成藏起到明显控制作用,对砂岩型铀矿成矿的制约也不可忽视。砂岩型铀矿通常就位于盆地边缘构造斜坡带和盆地内部隆起附近。隆起对砂岩型铀矿成矿的控制具体体现在:控制地下水补-径-排体系、控制层间氧化作用、控制沉积相带发育、伴生断裂促进物质输运以及为成矿供给铀等。中国北方沉积盆地中新生代以来经历复杂的构造活动,盆地域内非均衡发展而多形成隆起,因此我国铀矿找矿尤其需要重视隆起对铀成矿的控制。其中,盆地内部找矿应重点关注被大幅抬升的隆起,而盆地边缘构造斜坡带上找矿需重视微隆起以及基底上覆地层的褶皱。将隆起作为关键控矿要素,优选适用的攻深找盲方法,精细刻画盆地基底隆升形成的背斜、褶皱及伴生断裂,可有效提高铀矿找矿效率并拓展铀矿找矿空间。

Constraints of Uplift on Sandstone-type Uranium Mineralization and Its Implications for Prospecting

Paleo-uplifts in sedimentary basins play a significant role in controlling the accumulation of oil and gas, and their impact on sandstone-type uranium mineralization should not be underestimated. Sandstone-type uranium deposits are typically located on the slopes at the margins of basins and near the uplifts within the basins. The constraints of uplifts on the sandstone-type uranium mineralization are particularly evident in the control of groundwater recharge-runoff-discharge system, the regulation of interlayer oxidation reactions, the influence on sedimentary facies development, the promotion of material transport through associated faults, and the supply of uranium for mineralization. Since the Cenozoic era, the sedimentary basins in northern China have undergone complex tectonic activities, resulting in the formation of multiple uplifts due to the uneven development within basins. Therefore, in uranium exploration in China, particular attention needs to be paid to the control of uplifts on uranium mineralization. In this regard, exploration within the basin should focus on uplifts that have undergone significant tectonic uplift, while exploration on the slopes at the margins of basins should emphasize micro-uplifts and folds in overlying formations of the basement. Considering uplifts as key ore-controlling factors, selecting appropriate prospecting methods, and finely characterizing the anticlines, folds, and associated faults formed by the uplift of the basin basement can effectively enhance uranium prospecting efficiency and expand the uranium prospecting space.