华中超高压变质带中榴辉岩的稀土元素地球化学

根据ＲＥＥ含量及其分配模式，华中超高压变质带中榴辉岩可大体分为六种类型，即ＬＲＥＥ富集型、ＬＲＥＥ富集＋Ｅｕ正异常型、ＬＲＥＥ富集＋Ｅｕ负异常型、ＲＥＥ平坦型、ＭＲＥＥ（中稀土）富集型和ＨＲＥＥ富集型，主要为ＬＲＥＥ富集型和ＬＲＥＥ富集＋Ｅｕ正异常型，不同地区榴辉岩ＲＥＥ类型可进行对比，不同地区同ＲＥＥ类型榴辉岩的ＲＥＥ特征相似。原岩恢复结果表明榴辉岩的原岩主要为来源于相对富集地幔的大陆拉斑玄武岩

REE GEOCHEMISTRY OF ECLOGITES FROM THE ULTRAHIGH PRESSURE METAMORPHIC BELT IN CENTRAL CHINA

Based on their REE contents and REE patterns, eclogites from the ultra\|high pressure metamorphic belt in central China may be roughly divided into six types including LREE\|rich, LREE\|rich positive Eu anomaly, LREE\|rich, LREE\|rich negative Eu anomaly, REE pattern\|smooth, MREE\|rich and HREE\|rich. The LREE\|rich, LREE\|rich positive Eu anomaly and LREE\|rich negative Eu anomaly types of eclogites are dominant. REE types of eclogites in different areas can be compared and the REE features of the same REE type of eclogites in different areas are similar. The results of reconstruction of the primary rocks show that the primary rocks of eclogites possibly are dominated by continental tholeiites which are the product of partial melting of relatively fertile mantle and the rocks of tholeiite crystallization\|differentiation. There is perfect evolution relationship among the primary rocks of the LREE\|rich, LREE\|rich positive Eu anomaly and LREE\|rich negative Eu anomaly types of eclogites and among those of the REE pattern smooth and MREE\|rich types of eclogites, the former three types were derived from continental settings and the latter two from nearly oceanic settings. Meanwhile, it is concluded that the mantle sources of primary rocks of the eclogites are inhomogeneous and the primary rocks of eclogites in this area appear to have undergone varying degree of crustal contamination.