中文摘要：

中蒙边境及邻区位于西伯利亚板块、塔里木板块和华北克拉通的结合部位，是全球范围内重要的铀多金属成矿带之一。受多期次构造岩浆活动影响，该区前侏罗纪变质岩块体和中新生代火山-沉积岩分布广泛，深大断裂纵横交错，各类铀矿床（矿化区）星罗棋布。根据围岩类型，结构构造及成矿过程可将该区铀矿床划分为6种类型：（1）火山岩型；（2）砂岩型；（3）岩脉型；（4）褐煤型；（5）交代岩型；（6）磷灰盐型。其中火山岩型和砂岩型铀矿床具有重要经济意义。 区域矿产地质研究表明，中蒙边境产出的大部分铀矿床（矿化区）与前侏罗纪变质岩块体具有密切时空分布关系。前侏罗纪变质块体可划分为2部分：（1）前寒武纪高级变质岩；（2）古生代中、低级变质岩。铀的亲石元素特性致使其在壳-幔物质发生分异时富集于地壳的硅铝层。鉴于在地壳长期演化历史中，古老变质岩已具备有较高的铀含量，那么它们在显生宙构造-岩浆活动中就为铀的富集成矿提供有利的物质条件。显生宙构造运动的形式除了断裂活化外，也包括陆相沉积盆地的上隆和下陷。铀在地壳硅铝层中的富集是通过2种方式实现的：（1）陆壳的深熔和岩浆的分异作用；（2）富铀岩体（层）的风化剥蚀和再沉积活动。研究结果表明，铀的富集过程十分缓慢，其中火山岩型铀矿床的形成作用就是长英质岩浆活动的组成部分。 火山型铀矿床主要出现在中蒙边境最东端蒙古国境内，它们是中蒙古-额尔古纳地块伸展构造环境（裂陷槽为大量高钾长英质火山岩所充填）中构造-岩浆作用及相关流体活动的产物。长英质火山杂岩体内产出的若干处大型铀矿床（区）和铅-锌-银-铀矿床即是很好的佐证。一般来讲，具有强烈分异特点的富碱性火山岩及相关铀矿床大都在?

英文摘要：

The Sino-Mongolia border region and its neighboring areas are located at the convergence zone of the Siberian platform, Tarim plate and North China craton, and is one of the most important uranium metallogenic provinces in the world. Deep-seated faults, pre-Jurassic metamorphic terrane and various types of uranium deposits （mineralized areas） are well developed in the region due to the multiphase tectonic-magmatic events. These uranium deposits can be classified into six types in term of their host rocks, geometry and ore-forming processes： （1） volcanic type; （2） sandstone type; （3） vein type; （4） lignite type; （5） metasomatitic type; （6） phosphorite type, among which the first two types of uranium deposits bear the most important economic significance. 〈br〉 Regional metallogenic studies show that most of the uranium deposits （or mineralized areas） occurring within the Sino-Mongolian border region are closely spatially associated with pre-Jurassic metamorphic terrane consisting of two parts： （1） Precambrian high-grade metamorphic rocks; （2） Paleozoic lightly metamorphic rocks. Since uranium is a lithophile element, it is more easily enriched in the acidic sialic section of the crust during the differentiation of mantle matter. Because these old formations had already been enriched in uranium through the long geological evolution, they might have provided the precondition for economic enrichment of uranium in the Phanerozoic tectonic movements when downfaulted or downwarped continental basins occurred with terrestrial dominated sediments. Where the uranium-enriched geological bodies existing in one region are eroded, all of them can serve as the source for the sandstone-type deposits. The early tectonic event occurring around 176 to 125Ma provided suitable conditions for the oxidization of the groundwater table and the formation of low-grade uranium mineralization area. In the Phanerozoic tectonic-activated regions, the economic enrichment of uranium usually occurred