Sun Da, Xia Fei, Meng Fanmin, Nie Fengjun, Liu Xu, Zhang Wenwen, Wang Qing
School of Earth Sciences, East China University of Technology, Nanchang, Jiangxi Province 330013, China.
State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, Jiangxi Province 330013, China.
ACS Omega. 2025 Jan 6;10(1):912-928. doi: 10.1021/acsomega.4c08072. eCollection 2025 Jan 14.
In recent years, the Telaaobao Mineral Area in the Northwestern Ordos Basin has been newly discovered as a uranium mineralization area with its ore-bearing target layer located within the Lower Cretaceous Huanhe Formation, belonging to a new area and a new layer, and has great uranium deposit formation potential. In order to deeply study the issues of the ore-bearing target in this area, such as the petrology, mineralogy, and uranium mineralization of the ore-bearing sandstone, based on the data from field geological investigation and drill core logging, the petrological characteristics of the ore-bearing sandstone of the target layer are preliminarily interpreted using a polarizing microscope and a scanning electron microscope, and the uranium mineral composition, uranium occurrence state, and uranium deposit mineralization are investigated through the electron probe microanalysis technique in this paper. The results show that the target layer sandstone in the study area has the characteristics of proximal deposit and has undergone significant epigenetic alteration and transformation, producing favorable conditions for uranium- and oxygen-containing water transportation and uranium mineralization. The uranium minerals are dominated by the independent coffinite with the UO content ranging from 40.93 to 60.45%, followed by the titanium-uranium oxides. The uranium minerals occur in various forms, mainly in the edge or fissure of the debris particles, in the edge of the framboidal pyrite, around the biotite or within its cleavage fissures, and on the surface of the chlorite. In addition, a preliminary uranium mineralization model was also established in the Telaaobao Mineral Area. The uranium mineralization in the Telaaobao Mineral Area results from the combined action of the infiltrating and ascending fluids. The uranium- and oxygen-containing fluids from the source area infiltrate downward into the target sandstone layer and meet the ascending reducing fluids from the depth, producing a redox barrier in Huanhe Formation, within which U is reduced to U for precipitation, leading to the formation of uranium mineralization.
近年来，鄂尔多斯盆地西北部的特涝宝矿田被新发现为一个铀矿化区，其含矿目的层位于下白垩统环河组内，属于新区域、新层位，具有较大的铀成矿潜力。为深入研究该区域含矿目的层的岩石学、矿物学及含矿砂岩铀矿化等问题，本文依据野外地质调查和钻孔岩心录井资料，利用偏光显微镜和扫描电子显微镜对目的层含矿砂岩的岩石学特征进行了初步解析，并通过电子探针微分析技术研究了铀矿物组成、铀赋存状态及铀矿床矿化情况。结果表明，研究区目的层砂岩具有近源沉积特征，经历了显著的后生蚀变改造，为含铀含氧水的运移及铀矿化创造了有利条件。铀矿物以独立的晶质铀矿为主，UO含量为40.93%至60.45%，其次为钛铀氧化物。铀矿物赋存形式多样，主要分布在碎屑颗粒边缘或裂隙、莓球状黄铁矿边缘、黑云母边缘或其解理裂隙内以及绿泥石表面。此外，还建立了特涝宝矿田初步的铀矿化模式。特涝宝矿田的铀矿化是渗流上升流体共同作用的结果。来自源区的含铀含氧流体向下渗入目的砂岩地层，与深部上升的还原流体相遇，在环河组形成氧化还原障，其中U被还原为U沉淀，从而形成铀矿化。
