东胜铀矿床的断隆叠加成矿作用

东胜矿床是近几年来在鄂尔多斯盆地东北部发现的一个特大型铀矿床,对该矿床成矿作用的研究具有重要的理论意义和找矿价值.早期人们认为该铀矿床属层间氧化带型矿床,但经对资料的分析认为用层间氧化带的观点很难完全解释东胜铀矿床的成矿问题.利用遥感技术研究了矿床的区域成矿构造背景,发现本区存在一断隆构造,矿床处于该断隆构造的南缘.该断隆构造叠加在早期蚀源区-斜坡带成矿背景之上.在此基础上,结合前人研究成果,对古层间氧化带型铀矿进行了追溯,并探讨了断隆叠加与铀矿化形成的关系,提出断隆构造的发生、发展促进了东胜矿床成矿作用的演化.从断隆的隆升作用,构造-热事件作用和断隆边缘断裂的导通作用等方面,论述了断隆构造的叠加是东胜铀矿床叠合成矿的诱因.由于东胜铀矿床是断隆叠加成矿作用形成的铀矿床,因此,对这类矿床的勘查,不仅要重视沉积体系和氧化带的研究,还要重视构造和深部物质运移迹象的研究.

Fault-uplift Superimposed Mineralization of Dongsheng Uranium Deposit

Dongsheng deposit is an oversize uranium deposit which was found at the northeast of Ordos basin in recent years, so the research of this deposit has significance for the metallogenic theory and prospecting. It was considered as an interlayer oxidation zone type deposit early, but through the further analysis of the data, it was found that this viewpoint could not explain the mineralization process completely. A fault-uplift structure was found by using the remote sensing technology to study the regional tectonic background, and the deposit is on the south of it. Also this fault-uplift is considered superimposed on slope zone metallogenic background which is the early provenance area. Based on these work, a theory that the generation and development of fault-uplift promote the evolution of mineralization of Dongsheng uranium deposit was put forward after reviewing the theory of paleo-interlayer-oxidation type sandstone-hosted uranium deposit and the relationship of fault-uplift superimposition and uranium mineralization are discussed. Afterward, the viewpoint that the superimposition of fault-uplift is the inducement of superposition metallogenesis of Dongsheng deposit is demonstrated from many aspects, such as the uplift effect of fault-uplift、the tectothermal events and the guidance of the fracture on the margin of the fault-uplift. Not only the depositional system and oxidation zone, but also the geological structure and the evidence of the movement of the deep substance in the earth should be attach importance to for the exploration of this type deposit.