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应用阴极发光和离子探针技术,对北祁连山高压变质带两个榴辉岩样品中的锆石进行了结构和形态学观察以及原位U-Pb定年。所获得的年龄值分别为463±6和468±13 Ma,代表了本区榴辉岩相变质时代。这是北祁连山加里东期高压变质作用的最早记录,可能代表了大洋板块俯冲进入上地幔经受榴辉岩相变质的时间。
The zircons in two eclogite samples of the high-pressure metamorphic belt in North Qilian Mountains were observed by structure and morphology and in-situ U-Pb dating by using cathodoluminescence and ion probe techniques. The obtained age values are 463 ± 6 and 468 ± 13 Ma, respectively, representing the era of eclogite facies metamorphism in this area. This is the earliest record of the high pressure metamorphism in the Caledonian North Qilian Mountains and may represent the time when the oceanic plate subducted into the upper mantle and experienced eclogitic facies metamorphism.