【摘要】 胶东地区发育大面积的早无古代变质地层──荆山群。该套岩系经历了三期五个阶段的变质作用，峰期温压条件为T＝700～750℃，p＝0．50～0．60GPa，达角闪麻拉岩相。变质作用pTt轨迹为逆时针形式，反映早元古代陆缘壳内裂陷带的闭合过程。更多还原

【Abstract】 The widespread early Proterozoic metamorphic sequence, the jingshanGroup, has experienced five periods of metamorphism in three episodes. The temperatureand pressure of its peak stage in amphibole granulite facies is around 700～750℃, and0.50～0.60 GPa. The metamorphic pTt path is counter clockwise, which reflects theenclosing process of an ensialic rifted belt on the continental margin during earlyProterozoic.更多还原