【摘要】 碱性岩的副矿物磷灰石和榍石是岩体中稀土元素的主要载体矿物。它们的稀土分布模式与母岩相同,向右陡倾斜,磷灰石的Eu负异常明显,榍石具Ce正异常,锆石呈大体对称“V”形模式,Eu负异常最大。与花岗岩中同一矿物对比,上述矿物都体现了幔源碱性岩浆轻稀土富集,Eu亏损小的特点。磷灰石、榍石和锆石相应富集了母岩中的轻、中、重稀土元素,稀土元素的这种置换行为主要是矿物晶体化学性质控制的。更多还原

【Abstract】 The accessory minerals, apatite and sphene are the main, carriers of REE in alkaline rocks. Their REE chondrite-normolized patterns decline sharply to the right as those at the host rocks. In the patterns an obvious negative Eu anomaly and a positive Ce anomaly can be seen in apatite and sphene, respectively. Zircon from alkaline rocks is different in REE pat-tern, i.e., a nearly symmetric "V"-shaped pattern with a maximum negative Eu anomaly. Compared with the equivalents from granites, apatite, sphene and zircon from alkaline rocks are all characterized by higher (La/Yb)N ratio and less Eu depletion. As to the relative contents of REE in minerals, apatite, sphene and zircon are enriched in LREE, MREE and HREE respectively, depending on their crystallochemical properties.更多还原