赣中周潭群变质沉积岩的微量元素地球化学研究

对赣中周潭群变质沉积岩及其石榴子石等造岩矿物的稀土元素地球化学进行了详细研究.结果表明:造岩矿物只携载了岩石中少部分稀土元素,而大部分稀土元素赋存在副矿物的晶格中;变质过程中稀土元素在石榴子石变斑晶与岩石间达到了分配平衡,石榴子石/岩石间的稀土元素分配明显受体系化学组成所制约;变质岩脉及其矿物的稀土元素组成显示清楚的四重效应,其Zr-Hf,U-Th和Y-Ho等元素对也与变质岩发生了一定程度的分异,它们可作为周潭群在变质过程中流体作用存在的判别标志.

STUDY ON THE TRACE ELEMENT GEOCHEMISTRY OF THE ZHOUTAN GROUP METASEDIMENTARY ROCKS IN CENTRAL JIANGXI PROVINCE

Detailed REE geochemical studies of the Zhoutan Group metasedimentary rocks in central Jiangxi Province and rock-forming minerals such as garnet were conducted and the results showed that the REEs are partly present in the rock-forming minerals and are dominantly contained in the lattice of accessory minerals.In the process of metamorphism the REEs between garnet porphyroblast and rock and the partitioning of REEs between garnet and host rock are obviously controlled by the chemical composition of the system.The REEs compositions of metamorphic veins and their minerals display remarked lanthanide tetrad effects and the element pairs Zr-Hf,Y-Ho and U-Th have also experienced a certain degree of fractionation with respect to the metamorphic rocks and they can be used as discriminating indicators for the occurrence of fluid processes in the process of metamorphism of the Zhoutan Group.