【摘要】 江苏北部的榴辉岩出露于东海群变质岩系中,榴辉岩的产状是:1)呈似层状或透镜状产于东海群片麻岩中;2)呈不规则团块状产于超镁铁岩中,或与超镁铁岩伴生。全岩分析结果表明,前者相当橄榄拉斑玄武岩或石英拉斑玄武岩,后者相当橄榄玄武岩或橄榄拉斑玄武岩。榴辉岩稀土元素丰度和分配型式变化很大,多数为轻稀土富集型,少数为亏损型和铕正异常型。根据主元素和稀土元素判断,榴辉岩的原岩大致相当于大陆裂谷型基性火成岩。5个榴辉岩全岩样品钐、钕同位素测年,获得1108±23Ma等时线年龄。∑_Nd（t）值<0,原岩可能来源于富集型地幔。更多还原

【Abstract】 Eclogite in northern Jiangsu is exposed in metamorphic rocks of the Donghai Group. It has two kinds of geologic occurrence; (1) it occurs in the bed-like or lenticular form in gneiss of the Donghai Group, and (2) it occurs as irregular nodules in ultramafic rocks or is associated with ul-tramafic rocks. The results of bulk rock analysis show that in the former case it is equivalent to olivine tholeiite or quartz tholeiite while in the latter case it corresponds to olivine basalt or olivine tholeiite. The abundance and distribution patterns of REE of eclogite samples vary very much: most of them are LREE-enriched while a few are depleted in LREE and have Eu positive anomaly. According to the major element and REE geochemistry, it is determined that the protolith of the eclogite is approximately equivalent to continental rift basic igneous rocks. Whole-rock Sm-Nd dating of 5 eclogite samples yielded an isochron age of 1108±23 Ma. The value of eNd(t) is less than 0, and so it is inferred that the rocks might be derived from the mantle.更多还原