Important Events and Chronological Framework of the Early Precambrian Granulite Terrain, Northwestern Hebei Province

Based on the chronological data and relevant geological evidence, the chronological framework of the major geological events of the granulite terrain in northwestern Hebei Province and its adjacent areas has been established. Basic lava eruption occurred in the span of 2868–2932 Ma, resulting in the formation of the early crust. The TTG magma emplacement took place c.2761 Ma ago. Subsequently basic magma intruded into the supracrustal rocks at 2650 Ma, resulting in crustal thickening. The thickening was enhanced at 2561–2503 Ma by the widespread intrusions of granodioritic magma. In the period of 2477–2461 Ma charnockite intruded, accompanied by regional granulite facies metamorphism. The second stage of granulite facies metamorphism occurred c. 2300 Ma ago, and finally pink granite intrusions at 2144–2087 Ma resulted in the formation of a granite zone.