| 华中榴辉岩带地球化学和年代学研究 |
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| 引用本文： | 张泽明,游振东.华中榴辉岩带地球化学和年代学研究[J].矿物学报,1994,14(3):215-222. |
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| 作者姓名： | 张泽明 游振东 |
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| 作者单位： | 中国地质大学!武汉，430074，中国地质大学!武汉，430074，中国地质大学!武汉，430074 |
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| 摘 要： | 根据地质产状，华中高压超高压变质带中的榴辉岩可划分为与超基性岩伴生的P类和与片麻岩、斜长角闪岩等伴生的G类。它们具有不同的地球化学特征，但均为大洋基性火成岩经复杂成分演化作用的产物。全岩-矿物Sm－Nd和颗粒锆石207Pb-206Pb年代学研究表明，超高压变质作用很可能发生在加里东期（480Ma）；而印支期（265Ma）则可能是超高压变质岩的后期高压退变质改造阶段。
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| 关 键 词： | 地球化学 同位素年代学 加里东期超高压变质作用 华中榴辉岩带 |
GEOCHEMISTRY AND CHRONOLOGY OF THE ECLOGITE BELT IN CENTRAL CHINA |
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| Zhang Zeming, You Zhendong, Han Yujing.GEOCHEMISTRY AND CHRONOLOGY OF THE ECLOGITE BELT IN CENTRAL CHINA[J].Acta Mineralogica Sinica,1994,14(3):215-222. |
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| Authors: | Zhang Zeming You Zhendong Han Yujing |
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| Abstract: | The eclogites building up an eclogite belt measuring 800 km in length between North China and the Yangtze plate have been investigated in terms ma jor and trace elements, REE and Sm and Nd isotopic compositions. On the basis of their occurrence, the eclogites can be divided into two groups. Group P is associated with peridotites and group G with gneiss, amphibolite and marble.The eclogites seem to be derived from ocean-floor tholeiites with geochemical characteristics very similar to those of the present-day MORB. The fractional crystallization, contamination and metamorphic differentiation have had a significant effect on the eclogitic composition. The high-pressure metamorphic rocks were introduced into the wallrocks of amphibolite facies metamorphism in response to tectonic movement. Whole-rock-mineral Sm-Nd isochron and single zircon Pb-Pb dating indicate that a very high-pressure metamorphism occurred during the Caledonian (480 Ma), the protolith age of eclogite is probably 2. 06 Ga, whi1e an age of 265 Ma may be assigned to the highpressure retrograded metamorphism of eclogites. Many other samples show marked Sm-Nd disequilibrium partitioning between garnet and clinopyroxene and the geological significance of their ages (55-329 Ma ) is debatable. |
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| Keywords: | eclogite belt in central China geochemistry isotope chronology Caledonian very high-pressure metamorphism |
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