| 鄂尔多斯盆地砂岩型铀矿成矿地质条件和关键控矿要素分析 |
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| 引用本文：俞礽安,金若时,李彤,杨彤旭,朱强,唐永香.2023.鄂尔多斯盆地砂岩型铀矿成矿地质条件和关键控矿要素分析[J].地球学报,44(4):689-706. |
| DOI：10.3975/cagsb.2022.122902 |
| 摘要点击次数: 2002 |
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| 基金项目:国家自然科学基金委重点支持项目(编号: 92162212);中国地质调查局地质调查项目(编号: DD20230045;DD20221678-05) |
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| 中文摘要:鄂尔多斯盆地是我国北方重要的产铀盆地之一, 具有优越的成矿地质条件和找矿前景。本文通过总结该盆地的砂岩型铀矿调查研究成果, 系统梳理铀矿成矿地质条件, 探讨关键控矿要素和找矿潜力。结果表明, 鄂尔多斯盆地外部蚀源区铀源丰富, 北部造山带地质体的Th/U比值和ΔU铀迁移量相对最大, 对盆内的铀源贡献率最高; 盆缘斜坡带发育的微隆起带构造控制了铀矿床的空间定位, 断裂构造对盆地西缘和西南缘地区的铀成矿发挥了控制和改造作用; 古气候、沉积环境决定了由盆地东南部向西北部地区, 含铀层位由直罗组下段下亚段逐渐演变成直罗组下段上亚段, 表现了明显的迁移规律性; 直罗组下段的煤线和碳质泥岩发育特征制约了铀矿层的空间分布; 铀矿体主要发育在辫状河主河道边部和辫状河三角洲分流河道, 优先富集于有机质丰富、非均质性强、岩性多变的部位。在此基础上, 建立了6个关键控矿要素和相关找矿判别指标, 针对盆内5个铀矿(矿化)集中区分析了砂岩型铀矿的找矿潜力, 提出了下一步找矿方向 |
| 中文关键词:砂岩型铀矿 铀源条件 控矿构造 关键控矿要素 鄂尔多斯盆地 |
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| Analysis of Metallogenic Condition and Key Ore-controlling Factor of Sandstone-hosted Uranium Deposits in the Ordos Basin |
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| Abstract:The Ordos Basin is an important uranium-bearing basin in the north of China. It has superior metallogenic geological conditions and prospecting potential. Based on the summary of investigation and research results of sandstone-type uranium deposits in the basin, we systematically analyzed the geological conditions of uranium mineralization. Moreover, herein we discuss the key ore control factors and prospecting potential. The results showed that the outer source area of the Ordos Basin is rich in uranium, and the high thorium/uranium ratio and uranium migration of the northern orogenic belt geological body indicated that it provides the greatest contribution rate to the uranium source in the basin. The micro uplift structure developed in the slope zone of the margin controls of the basin, the spatial positioning of the uranium deposits, and the fault structure control and reform uranium mineralization in the western and southwestern margins of the basin. The paleoclimate and sedimentary environment indicated that, from the southeast to the northwest region of the basin, the uranium-bearing horizon gradually evolved from a lower sub member of the lower Zhiluo Formation to an upper sub member of the lower Zhiluo Formation, showing evident migration regularity. The development characteristics of the coal line and carbonaceous mudstone in the lower part of the Zhiluo Formation restricted the spatial distribution of the uranium deposits. Uranium ore bodies primarily developed at the edge of the braided river main channel and the braided river delta distributary channel, with preferential enrichment in areas rich in organic matter and with strong heterogeneity and variable lithology. On this basis, six key ore control factors and related prospecting discrimination indices were established. The prospecting potential of sandstone-type uranium deposits was analyzed for five uranium ore (mineralization) concentration areas in the basin, and the next prospecting orientation was proposed. |
| keywords:sandstone-type uranium deposit uranium source conditions ore controlling structure key ore controlling factors Ordos Basin |
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