稀土元素七组分图解类型划分及地质意义

根据轻稀土与重稀土含量的比例关系以及Sm/Gd与Dy/Er比值的变化关系,将稀土七组分曲线划分为H型(重稀土富集型)和L型(轻稀土富集型)两大类型,包括Ha,Hb,Hc和La,Lb,Lc6个基本类型。通过实例,论述了稀土七组分图解在地质研究,特别是在侵入序列划分、岩浆成因及演化特点分析、不同类型及不同时代花岗岩的对比以及变质原岩恢复、混合岩化作用过程分析中的作用和意义。

TYPES OF SEVEN-EVEN-NUMBERED CURVES AND THEIR GEOLOGICAL SIGNIFICANCES

Seven-even-numbered-element curves of REE can be used to reflect the characteristics of REE in rocks and minerals. The principles and methods to create the seven-even-num- bered-element curves of REE are briefly summerized. The types of such curves and their geological significances are emphasized. Based on the ratio of LREE to HREE and the ratio of Sm/Gd to Dy/Er, the seven- even-numbered-element curves of REE are classified into H-type (HREE enrichment type) and L-type (LREE enrichment type) which are further divided into Ha, Hb, Hc and La, Lb, Lc types respectively. It is clearly shown that these diagrams are very useful in Earth Sciences, especially in determining the successions of intrusives, interpreting the genesis and evolution of magma, the correlation of granites between different types and/or differ- ent times, the restoration of original rocks of metamorphic rocks as well as analysing the process of magmatization.