| 3075地区变质岩的原岩形成环境及其与铀成矿的关系 |
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| 引用本文：.1988.Primordial depositional environment of the metamorphic rocks and its implications in uranium mineralization of 3075 area[J].Mineral Deposits,7(3):60~70 |
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| 中文摘要:本文用各种手段和方法恢复3075地区变质岩的原岩及其形成环境，研究了各类岩石中铀的丰度、配分状态及其在变质作用中的活动规律、成矿作用。提出：变质岩的原岩形成环境是影响铀在原岩中初始富集的重要因素；原岩中铀的配分状态影响铀在变质作用中的行为和迁
移富集的程度。由此认为，变质作用、混合岩化作用是有利于铀活化、转移、富集成矿的外部条件，而变质岩的原岩形成环境及原岩中铀的配分形式是形成铀成矿物质基础的决定因素。 |
| 中文关键词:变质岩 原岩形成环境 铀的配分 铀成矿作用 |
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| Primordial depositional environment of the metamorphic rocks and its implications in uranium mineralization of 3075 area |
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| Abstract:The uranium behavior and its metallogenesis in metamorphic process were strongly influenced by such characteristics of the original rocks such as the rock type, primordial depositonal environment, rock-forming matieral source and uranium content. The activation, transference, and enrichment of uranium are related to the abundance and distribution of uranium in the original rocks. This paper deals with these problems according to the results of an overall research in 3075 area. On the basis of the field investigation, laboratory stndies on petrology, Petrochemistry, rare earth element components and other items, the original rocks of the metamorphic rocks and their primordial deposifional environment were reconstructed. It is inferred that the original rocks were a suite of continental arenaceus-argillaceous sedimentary rocks formed not far from the erosion source area and deposited in relatively stable littoral-ueritic environment. The modes of occurrence of uranium in vadous rock types in the area have been studied with the help of induced fission trace technique, and the result indicates that uranium exists mainly as “active uramium” and rarely in the form of isomorphism. Uranium migrated toward intergranular opening, cements and fissuses of the minerals during the progressive metamorphism, and toward the positions of chlorite and melnikovite-pyrite during the retrograde metamor phism. In the end, a large amount of uranium was activated and transferred toward favorable locations, such as suitable structural zones, and was concentrated in these places under the action of K-, Na-rich alkaline mixed metasomatic solutions. In the light of the above investigations, it is considered that metamorphism and migmatitic-metasomatic processes were favorable external conditions for uranium minerlization, wheraeas the primordial depositional environment of the original rocks made up material prerequisite. These factors must therefor be studied at the very beginning in search for this type of uranium deposit in metamorphic areas. |
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