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刘志宏 王安建 李晓峰
Liu Zhi-hong1, Wang An-jian2, Li Xiao-feng3
Abstract: The late Archean collision orogenic belt in Wutaishan is situated in the central part of the North China Plate. It is separated from the high grade gray gneiss terrane at north Hengshan by dutile shear zones (DDZ)distributed over the north side of Hutuo River Cenozoic fault depression, and fro m the high grade terrane at southwest Fuping by Longquanguan DDZ, to form a wedge-shape terrane opening towards southwest. Based on rock association metamorphic deformation, magmatism and geochronological data, the collision orogenic belt can be subdivided into three tectonic units: the south tectonic section (STS) (fore-arc melange zone), the central tectonic section (CTS) (paleo-island arc), the north tectonic section (NTS) (back-arc melange zone). The boundaries between them are giant DDZ. The rocks in the NTS and STS are metamorphosed to amphibolite facies, whereas those in the CTS to greenschist facies. The differences of metamorphic degrees in the three sections are due to their tectonic environments. Studies on the mineral assemblages and metamorphic reactions indicate similar PTt paths of orogeny for these three tectonic sections. The temperatures and pressures of the metamorphism increased apparently in the three tectonic sections from early to peak stage (STS: ≤ 500℃, 0.4GPa--589～670℃, 0.86GPa: CTS: 375～400℃, ＜0.5GPa--500～ 560℃, ≤0.5GPa; NTS: 500℃, ≤0.4GPa--569～663℃, 0.98～ 1. 36GPa), which mainly related to the crustal subduction of the fore-arc and back-arc melange zones in the island-arc-continent, continent-continent collisions. The isothermal decompression of the metamorphism from peak to late stage (STS: 589～ 670℃, 0.86GP--560～650℃, 0.2～ O.3GPa; CTS: 500～ 560℃, 0.5GPa--400～ 445, 0.1～ 0.4GP; NTS: 569～ 663℃, 0.98～ l.36GPa--560～ 650℃, 0.2～ 0.3GPa) was related to the crustal detachment which was resulted from the extensive longitudinal extension.Tectonism provided the dynamic basis for metamorphism.
刘志宏 王安建 李晓峰. 五台山晚太古代碰撞造山带的变质作用演化[J]. J4.
Liu Zhi-hong1, Wang An-jian2, Li Xiao-feng3. METAMORPHISM EVOLUTION OF THE LATE ARCHEAN COLLISION OROGENIC BELT IN WUTAISHAN[J]. J4.