中国北方主要产铀盆地砂岩铀矿成矿年代学及成矿铀源研究  

Research on Geochronology and Uranium Source of Sandstone-hosted Uranium Ore-Formation in Major Uranium-Productive Basins, Northern-China

作　　者：夏毓亮[1] 刘汉彬[1] 林锦荣[1] 范光[1] 侯艳先[1] 

机构地区：[1]核工业北京地质研究院,北京100029

出　　处：《中国核科技报告》2004年第2期77-87,共11页China Nuclear Science and Technology Report

摘　　要：提出用铀矿石样品U Ra平衡系数修正样品的铀含量,再进行U Pb等时线拟合,从而获得北方主要产铀盆地更符合实际的成矿年龄。对含矿砂体中碎屑锆石与相应蚀源区中酸性火成岩类锆石U Pb同位素年龄的对比研究,证明了含矿砂体直接来自中酸性火成岩类的剥蚀,指出该物源是形成富铀砂体的物质基础。通过对蚀源区岩石和盆地含矿地层不同部位的砂体岩石样品的U Pb同位素体系演化特征的研究,论证了地浸型砂岩铀矿的铀源一是蚀源区活性铀高的中酸性火成岩类;另一铀源是有铀预富集的沉积砂体。A method is developed for correcting uranium content in uranium ore samples by considering the U-Ra equilibrium coefficient, then a U-Pb isochron is drawn up. By performing the above correction ore-formation ages of sandstone-hosted uranium mineralization which may be more realistic have been obtained. The comparative research on U-Pb isotopic ages of detritic zircon in ore-hosting sandstone and zircon in intermediate-acid igneous rocks in corresponding provenance area indicates that the ore-hosting sandstone is originated from the erosion of intermediate-acid igneous rocks and the latters are the material basis for the formation of the uranium-rich sandstone beds. On the basis of the study on U-Pb isotopic system evolution of the provenance rocks and sandstones from ore-hosting series, it is verified that the uranium sources of the sandstone-hosted uranium deposit are: the intermediate-acid igneous rocks with high content of mobile uranium, and the sandstone bodies pre-concentrated uranium.

关 键 词：中国北方 产铀盆地 成矿年龄 铀源 地质年代学 

分 类 号：P619.14[天文地球—矿床学]