敦煌方山口大型钒磷铀矿床的稀土元素地球化学研究

REE geochemistry of the Fangshankou large-size V-P-U deposit in Dunhuang City, Gansu Province

采用等离子光谱法对敦煌方山口钒磷铀矿床围岩及矿石的稀土元素含量进行了测定 ,结果显示本区稀土元素多为LREE富集型 ,各样品间稀土元素的含量、组成和Ce、Eu亏损程度等差异 ,主要是沉积环境变化的反映。通过相关性分析得知 ,ΣREE与粘土、有机质、V2 O5等呈负相关 ,与CaO、MgO、P2 O5和U呈正相关 ,并认为ΣREE与有机质的负相关性为成岩后生改造的结果 ,与其他化学成分之间的关系均是沉积条件与沉积过程复合作用的结果。

The ICP_AES method was applied to measure the abundances of rare earth elements in wallrock and ore samples from the Fangshankou V_P_U deposit in Dunhuang City, Gansu Province. The results show that REE of the deposit is usually of the LEE_enriched type, and that the differences of contents, compositions and negative anomalies of Ce and Eu between samples from the deposits reflect changes in sedimentary environments. Correlation analyses of the samples indicate that ΣREE, which is negatively related to abundances of clay, organic carbon and V 2O 5, is positively correlated to contents of CaO,MgO,P 2O 5 and U, and the negative correlation of ΣREE to organic carbon results from diagenesis, and that its relations to other chemical components are caused by sedimentary conditions combined with depositional process.