稀土元素的某些地球化学行为及对热液铀成矿的指示意义

通过对热液铀矿床稀土元素的研究,发现岩浆热液矿床、变质热液矿床及地下水热液矿床中铀的矿化作用,伴随有稀土元素,特别是重稀土元素的富集现象,主要是二者的迁移形式相同,富集条件类似。铀主要以碳酸铀酰络合物的形式迁移,CO_2是主要成分。迁移形式相同的铀、重稀土元素在合适的物理化学条件下,因络合物分解而共同沉淀富集,故重稀土的富集现象是热液铀成矿良好的指示。

SOME GEOCHEMICAL BEHAVIOUR OF REE AND THEIR INDICATING SIGNIFICANCE FOR HYDROTHERMAL URANIUM MINERALIZATION

Through the study of REE in hydrothermal uranium deposits,it is found" that uranium mineralization is associated with the concentration of REE,especially HREE in magmatie hydrothermal deposits ,metamorphic hydrothermal deposits'and undergraund hydrothermal deposits. The reason for the association of uranium with REE is that both of them are similar in the form of migration and conditions for concentration as well. Uranium is mainly migrated as carbonate-uranyl complexes,in which CO_2 is a principal constituent. Under the suitable physicochemical conditions,owing to the decomposition of complexes,uranium and HREE in the similar form of migration are precipitated and concentrated together. Therefore ,the phenomenon of HREE concentration is a good indicator for hydrothermal uranium mineralization.