Field Relationships,Geochemistry,Zircon Ages and Evolution of a Late Archaean to Palaeoproterozoic Lower Crustal Section in the Hengshan Terrain of Northern China

作     者：A. KRONER S.A. WILDE P.J. O＇BRIEN LI Jianghai C.W. PASSCHIER N.P. WALTE LIU Dunyi 

作者机构：Institut fiir Geowissenschafien Universitat Mainz D-55099 Mainz Germany School of Applied Geology Curtin University of Technology GPO Box U1987 Perth WA 6845 Australia Institut fiir Geowissenschafien Universitat Potsdam Postfach 601553 D-01553 Potsdam Germany Department of Geology Peking University Beijing 109009 China Chinese Academy of Geological Sciences 26 Baiwanzhuang Road Beijing 100037 China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2005年第79卷第5期

页      面：605-632页

核心收录：

学科分类：070902[理学-地球化学] 0709[理学-地质学] 07[理学] 

基　　金：funded by the German Science Foundation(DFG,grant Kr 590/62) the National Natural Science Foundation of China(grant Nos.49832030,49772143 and 49572140 to Li Jianghai) 

主　　题：Archaean to Palaeoproterozoic geology zircon age Hengshan terrain North China Craton 

摘      要：The Hengshan complex forms part of the central zone of the North China Craton and consists predominantly of ductilely-deformed late Archaean to Palaeoproterozoic high-grade, partly migmatitic, granitoid orthogneisses, intruded by mafic dykes of gabbroic composition. Many highly strained rocks were previously misinterpreted as supracrustal sequences and represent mylonitized granitoids and sheared dykes. Our single zircon dating documents magmatic granitoid emplacement ages between 2.52 Ga and 2.48 Ga, with rare occurrences of 2.7 Ga gneisses, possibly reflecting an older basement. A few granitic gneisses have emplacement ages between 2.35 and 2.1 Ga and show the same structural features as the older rocks, indicating that the main deformation occurred after -2.1 Ga. Intrusion of gabbroic dykes occurred at -1920 Ma, and all Hengshan rocks underwent granulite-facies metamorphism at 1.88-1.85 Ga, followed by retrogression, sheafing and uplift. We interpret the Hengshan and adjacent Fuping granitoid gneisses as the lower, plutonic, part of a late Archaean to early Palaeoproterozoic Japan-type magmatic arc, with the upper, volcanic part represented by the nearby Wutai complex. Components of this arc may have evolved at a continental margin as indicated by the 2.7 Ga zircons. Major deformation and HP metamorphism occurred in the late Palaeoproterozoic during the Luliang orogeny when the Eastern and Western blocks of the North China Craton collided to form the Trans-North China orogen. Shear zones in the Hengshan are interpreted as major lower crustal discontinuities post-dating the peak of HP metamorphism, and we suggest that they formed during orogenic collapse and uplift of the Hengshan complex in the late Palaeoproterozoic （〈1.85 Ga）.