【摘要】 攀枝花-西昌(攀西)麻粒岩一直被认为是扬子陆块西缘变质程度最高和最古老的结晶基底岩石。最近从麻粒岩中获得的单颗粒锆石U-Pb测年结果表明,攀西麻粒岩的原岩可能形成于古元古代晚期(1870±24 Ma)。17件锆石U-Pb的谐和年龄(858-778 Ma)可能是麻粒岩受新元古代地幔柱活动影响,在快速冷却和抬升过程中发生角闪岩相退变质作用的时代。这一时间正是全球Rodinia超大陆由汇聚转变为裂解地球动力学系统发生改变的重要时期。更多还原

【Abstract】 The Panxi (Panzhihua-Xichang) granulites have long been recognized as the oldest rock of the crystalline basement with the highest metamorphic grade on the western margin of the Yangtze Block. The TIMS zircon U-Pb dating results of the Panxi granulites in this paper indicate that the protoliths of these granulites were formed in the late Paleoproterozoic (1870±24 Ma). Seventeen zircon U-Pb concordant ages (from 858 to 778 Ma) show the time of amphibolite-facies retrogressive metamorphism of the Panxi granulites. Amphibolite-facies retrograde metamorphism took place during rapid cooling and uplift of the Panxi granulite, which was probably correlated with the Neoproterozoic mantle plume activities. This is the key period during which the geodynamic system of the global Rodinia Supercontinent was transited from amalgamation to break-up in the Neoproterozoic.更多还原