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报道了大别超高压变质带西部麻城四道河榴辉岩 -围岩剖面系统的元素和同位素地球化学研究成果 ,对超高压变质榴辉岩在俯冲和折返过程中的部分熔融作用进行了探讨 .研究表明 ,榴辉岩原岩性质类似于N -MORB ,其长英质围岩可分为TTG片麻岩和含石榴石花岗岩 ;两类长英质围岩Sm -Nd同位素特征与其寄主的榴辉岩相似 ;REE特征、w (Nb) /w(Ta)比值、Nd同位素组成及锆石U -Pb定年等地球化学证据支持了TTG片麻岩为大别地区陆壳俯冲过程中发生部分熔融作用而形成 ,其与超高压榴辉岩的关系属特殊的异地关系 ;含榴花岗岩为超高压榴辉岩折返过程中的部分熔融作用形成 ,但因其形成环境为石榴石稳定场的深度 ,故含榴花岗岩与超高压榴辉岩被视为近似原地的构造关系 .
The elemental and isotopic geochemical studies of the eclogite-surrounding rock profile system of the Sichenghe four-lane Ertic UHP metamorphic belt are reported, and the partial melting of the UHP metamorphic eclogites during subduction and reentry is discussed The study shows that the eclogites are similar to N-MORB in their original rocks, and their long quartzitic rocks can be divided into TTG gneiss and garnet-bearing granite. The Sm-Nd isotopic characteristics of two types of Changying quartzitic rocks are related to their host The geochemical evidence of REE, w (Nb) / w (Ta), Nd isotope composition and zircon U-Pb dating support the partial melting of TTG gneiss during continental subduction in the Dabie area , And its relationship with ultrahigh-pressure eclogite is a special relationship. The granitic pluton is formed by partial melting during the folding back of the UHP eclogite. However, due to its formation environment is the depth of the stable field of garnet, Therefore, the granitic plutons and the UHP eclogites are considered as similar in situ structural relationships.