相山火山塌陷盆地基底变质岩U的地球化学研究

本文对相山火山塌陷盆地基底变质岩U的丰度及赋存形式进行了研究。基底变质岩中U主要以分散吸附状态的非结构U存在于基质或矿物粒间，少量的U以微粒、超微粒的独立铀矿物形式存在于矿物的裂隙中或粒间。U－Pb同位素的研究表明变质岩中的U在变质作用及后期的其它地质作用中发生了重新分配，并有不同程度的丢失，原始U含量较高。火山岩与变质岩的地球化学特征有许多相似之处。因此，作者认为基底变质岩有可能为成矿提供U源。

GEOCHEMICAL STUDY OF URANIUM IN BASEMENT METAMORPHIC ROCKS OF XIANG SHAN VOLCANIC COLLAPSE BASIN

The abundance and the existence form of uranium in basement metamorphic rocks of Xiangshan volcanic collapse basin have been studied. The uranium exosts mainly in disseminated and absorption form, minoor uranium exists in the fissure or intergrainular space of mineras as micrograin and super micrograin uranium-bearing minerals. The uranium was redistributed during metamorphism. According to the result of U-Pb isotope system study, uranium in rocks was lost during subsequent geological processes in different extent. The comparison of geochemical characteristics of ore-bearing volcanic rocks and metamorphic rocks shows much similarity. Therefore, the authors suggest that basement metamorphic rocks of Xiangshan volcanic basin might provide some uranium for ore-formation.