粤北南雄界址地区铀矿空间分布特征与成矿预测

    Spatial distribution characteristics and metallogenic prediction of uranium deposits in Jiezhi Area in Nanxiong, Northern Guangdong

    • 摘要: 粤北南雄界址地区作为华南铀矿集区重要组成部分,近年来在该区新发现了砂岩型、花岗岩内带型及花岗岩外带型等多种类型铀矿化体系,具有独特成矿特征。本文通过野外地质调查、地球物理反演及矿床解剖,揭示了该区铀矿空间分布受控于岩体接触带、断裂构造及岩性界面三重复合因素。研究结果表明:①砂岩型铀矿赋存于白垩系松山组(K2s)氧化还原过渡带,形成受古水动力系统控制;②花岗岩型内带型铀矿发育于陂头岩体内北西西-近东西向硅化断裂带内及其上下盘次级带,呈现多期热液叠加特征;③花岗岩外带型铀矿发育于陂头岩体与寒武系地层接触部位附近,受李庄帚状构造体系控制;④建立了“深源活化-构造萃取-界面富集”三位一体成矿模式。通过综合信息预测了三处成矿有利地段,提出了勘查新方向。

       

      Abstract: The Jiezhi Area in Nanxiong, northern Guangdong, as a crucial part of the South China uranium ore cluster, has recently revealed a unique metallogenic system comprising sandstone-type, intra-granite-type, and peripheral-granite-type uranium mineralization. Based on field geological surveys, geophysical inversion, and deposit anatomy, this paper demonstrates that the spatial distribution of uranium deposits in this area is controlled by a tripartite composite mechanism involving rock mass contact zones, fault structures, and lithological interfaces. Key findings include: ①sandstone-type uranium deposits are hosted in the redox transition zone of the Cretaceous Songshan Formation(K2s), formed under the control of a paleo-hydrodynamic system. ②Intra-granite-type uranium mineralization occurs in the NWW- to near-EW-trending silicified fracture zones and subsidiary fractures within the Beitou pluton, exhibiting multiphase hydrothermal superposition. ③Peripheral-granite-type uranium deposits are distributed near the contact zone between the Beitou pluton and Cambrian strata, influenced by the Lizhuang broom-shaped structural system. ④A ternary metallogenic model of “deep-source activation, structural extraction, and interface enrichment” is proposed. Integrated analysis identifies three prospective metallogenic zones and proposes new exploration targets.

       

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