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    吐哈盆地地浸砂岩型铀矿成矿条件与盆地动力学演化

    Metallogenic conditions of in-situ leachable sandstone-type uranium deposits and dynamic evolution of the Turpan-Hami basin

    • 摘要: 提要:分析吐哈盆地气候、地貌景观、地下水动力学、大地构造及构造、层间氧化带发育条件、含矿目的层地质及地球化学特征等,认为吐哈盆地北部与南部(艾丁湖斜坡带、了南凹陷、南湖凹陷等)地浸砂岩型铀矿成矿条件存在明显差异,其根本原因是与盆地南北动力学演化的差异有关。依据盆地构造沉降、构造层序、受板块运动影响等特征,认为盆地构造演化分为5个阶段,其中第三演化阶段(C—T)挤压型前陆盆地沉积阶段奠定了盆地南北构造演化差异的基础,对中新生代地浸砂岩型铀矿的分布影响深远;第四阶段(J—K)弱伸展型断陷盆地阶段为南部地浸砂岩型铀矿的形成准备了物质基础;第五阶段新生代挤压型前陆盆地阶段(E—Q)为南部地浸砂岩型铀矿形成富集提供了充分的外部动力。

       

      Abstract: Abstract: Analyses of the climate, geomorphologic features, groundwater dynamics, tectonics and structure, development conditions of interlayer oxidation zones and geological and geochemical characteristics of the ore target beds suggest that the metallogenic conditions of in-situ leachable sandstone-type uranium deposits in the north of the Turpan-Hami basin are notably different from those in the south (the slope zone of Aydingkol Lake, Liaonang depression and Nangfu depression). The basic cause is related to the difference in dynamic evolution in the southern and northern parts of the basin. According to the characteristics of tectonic subsidence, tectonic sequences and influence by plate motion, the tectonic evolution of the basin can be divided into five stages, of which the third stage (Carboniferous to Triassic), the compression-type foreland basin sedimentary stage, laid the foundation of the differences in tectonic evolution between the south and north of the basin, and had profound influence on the distribution of Meso-Cenozoic in-situ leachable sandstone-type uranium deposits, the fourth stage (Jurassic to Cretaceous), the weak extensional-type downfaulted basin stage, provided the material foundation for the formation of uranium deposits in the south of the basin, and the fifth stage (Paleogene to Quaternary), the Cenozoic compressional-type foreland basin stage, provided the sufficient exterior dynamic force for the formation and enrichment of the uranium deposits in the south of the basin.

       

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