| 吐哈盆地西南缘地区砂岩型铀矿含矿目的层沉积相与铀矿化 |
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| 引用本文： | 聂逢君,张成勇,姜美珠,严兆彬,张鑫,张进,乔海明,周伟.吐哈盆地西南缘地区砂岩型铀矿含矿目的层沉积相与铀矿化[J].地球科学,2018,43(10):3584-3602. |
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| 作者姓名： | 聂逢君 张成勇 姜美珠 严兆彬 张鑫 张进 乔海明 周伟 |
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| 作者单位： | 1.东华理工大学核资原与环境国家重点实验室, 江西南昌 330013 |
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| 基金项目： | 二连盆地西缘隆起区卫境岩体抬升剥蚀与盆内铀成矿耦合机理研究成矿耦合机理研究41772068国家重点基础研究发展规划973计划2015CB453002国家自然科学基金项目41562006 |
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| 摘 要： | 吐哈盆地铀矿找矿工作因十红滩矿床的发现而取得了重要突破，之后又在八仙口、苏巴什等地区相继找到了铀矿体与铀矿化.尽管矿床的发现带来了与铀矿化有关的研究工作不断深入，然而，矿床层间渗入氧化成矿作用的关键控制因素——沉积相与微相并未引起人们的足够重视.通过分析盆地的构造演化、钻孔岩心观察和测井曲线分析，识别出含矿目的层西山窑组（包括一段、二段、三段）主要形成于辫状三角洲环境.西山窑组一段、三段沉积于辫状三角洲平原环境，而最为重要的含矿层——西山窑组二段则沉积于辫状三角洲前缘相的水下分流河道、河口坝、分流间湾等微相.镜下鉴定结果表明，目的层岩石类型主要为岩屑砂岩，长石岩屑砂岩，次要为岩屑长石砂岩.电子探针分析结果显示，铀的存在形式主要是独立铀矿物，即沥青铀矿和含钛铀矿物.连井剖面对比研究表明，含铀含氧流体自南东向北西方向迁移，形成的铀矿体主要为板状和卷状.沉积相、微相与铀矿化之间的关系研究表明，铀矿化发育在辨状三角洲水下分流河道微相与河口坝微相环境，或水下分流河道微相与分流间湾微相接触界面附近的岩石中，沉积相（或微相）界面是控制铀矿化的关键因素.
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| 关 键 词： | 砂岩型铀矿 沉积相 微相 铀矿化 吐哈盆地 沉积学 |
| 收稿时间： | 2018-03-15 |
Relationship of Depositional Facies and Microfacies to Uranium Mineralization in Sandstone along the Southern Margin of Turpan-Hami Basin |
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| Abstract: | The discovery of Shihongtan uranium deposit (SUD) is a breakthrough for uranium prospecting in the Turpan-Hami Basin, followed by the discovery of, some small deposits and uranium occurrences in Baxiankou to Subashi area. Although the discovery stimulates the research on uranium mineralization within the basin, the key controlling factor for mineralization-depositional facies and microfacies of uranium-bearing sandstones has not been paid enough attention. Based upon analysis of evolution for basinal tectonics and drilling core observation combining with logging characteristics, it is found in this paper the Xishanyao Fm., deposited in braided delta environment, can fall into three intervals (Ⅰ, Ⅱand Ⅲ). The Ⅰand Ⅲ deposited in delta plain facies, while Ⅱ deposited in delta front. As the most important target layer, the Xishanyao Fm.. Ⅱ consists of subaquaceous distributary channel, mouth bar and interdistributary bay microfacies. From microscopic observation, the target layer sandstones can be classified into lithic sandstone, feldspathic lithic sandstone and lithic feldspathic sandstone. Electronic microscopic probe analysis shows that uranium is in the form of independent minerals like uraninite and titanium-bearing uranium minerals. The sections of drilling holes demonstrate uranium ore body is either roll-like or tabular due to migration of uranium-oxygen-bearing fluid flow from southeast to northwest. The relationship between uranium mineralization and depsotional facies/microfacies shows that the valuable uranium mineralization is prone to enrich along the boundary between two different microfacies, such as subaquaceous distributary channel and mouth bar, or subaquaceous distributary channel and interdistributary bay. Hence, the microfacies boundary is the key controlling factor for interlayered seepage oxidation zone sandstone-type uranium deposit in the Turpan-Hami Basin. |
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