吉林夹皮沟地区变质作用与地壳演化

THE METAMORPHISM AND THE CRUSTAL EVOLUTION OF JIAPIGOU AREA JILIN PROVINCE

本区经历四期变质作用,太古宙上壳岩系麻粒岩相变质、晚太古宙英云闪长岩高角闪岩相变质、早元古宙紫苏花岗岩类低角闪岩相变质和元古宙绿片岩相变质。麻粒岩相变质期可分三个阶段,早期角闪岩相、峰期麻粒岩相和晚期角闪岩相,其P-T-t轨迹为逆时针,与IBC型轨迹相似。导致麻粒岩相变质作用的热源为英云闪长质岩浆的垫托作用,形成于岛弧或活动大陆边缘。区内广泛发育的钾长花岗岩与晚太古宙高角闪岩相变质作用晚期的深熔作用有关。

Four periods of metamorphism took place in Jiapigou area, Jilin Province. The granulite facies metamorphism can be recognized in the Archean supercrust rocks, the high amphibolite facies metamorphism appears in the late Archean tonalites, the low amphibolite facies metamorphism and the green schist facies metamorphism are found in the early proterozoic charnockites. The granulite facies metamorphism can be further classified into three stages: the early stage of amphibolite facies, the peak stage of grannulite facies and the late stage of amphibolite facies. The PTt path of the granulite facies metamorphism is clockwise and similar to IBC type. The heat source resulting in the granulite facies metamorphism is derived from the underplating process of tonalitic magma, which was formed in the active continental margin. The Origin of the Kaligranites cropped widely in this area is related with the anatexism occuring in the later period of the late Archean amphibolite facies metamorphism.