Paleoproterozoic crustal evolution of the Hengshan-Wutai—Fuping region,North China Craton

作     者：Chunjing Wei Jiahui Qian Xiwen Zhou 

作者机构：MOE Key Laboratory of Orogenic Belts and Crustal EvolutionSchool of Earth and Space SciencesPeking University Institute of GeologyChinese Academy of Geological Sciences 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2014年第5卷第4期

页      面：485-497页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 0704[理学-天文学] 

基　　金：financially supported by the National Natural Science Foundation of China(Grant Nos.41172055 and 41121062) the China Survey of Geology(1212011121062) 

主　　题：Bimodal magmatismMetamorphic P T pathPaleoproterozoic tectonic evolutionHengshan Wutai Fuping regionNorth China Craton 

摘      要：An arguable point regarding the Neoarchean and Paleoproterozoic crustal evolution of the North China Craton（NCC）is whether the tectonic setting in the central belt during the mid-Paleoproterozoic（2.35-2.0 Ga）was dominated by an extensional regime or an oceanic subduction-arc regime.A review of the midPaleoproterozoic magmatism and sedimentation for the Hengshan-Wutai-Fuping region suggests that a back-arc extension regime was dominant in this *** conclusion is consistent with the observation that the 2.35-2.0 Ga magmatism shows a typical bimodal distribution where the mafic rocks mostly have arc affinities and the acidic rocks mainly comprise highly-fractioned calc-alkaline to alkaline（or A-type）granites,and that this magmatism was coeval with development of extensional basins characteristic of transgressive sequences with volcanic interlayers such as in the Hutuo *** the final amalgamation of the NCC was believed to occur at ～1.85 Ga,recent zircon U-Pb age dating for mica schist in the Wutai Group suggests a collisional event may have occurred at ～1.95 *** metamorphic ages of ～1.85 Ga,obtained mostly from the high-grade rocks using the zircon U-Pb approach,most probably indicate uplifting and cooling of these high-grade *** is because（i）phase modeling suggests that newly-grown zircon grains in highgrade rocks with a melt phase cannot date the age of peak pressure and temperature stages,but the age of melt crystallization in cooling stages;（ii）the metamorphic P-T paths with isobaric cooling under 6-7 kb for the Hengshan and Fuping granulites suggest their prolonged stay in the middle-lower crust;and（iii）the obtained metamorphic age data show a continuous distribution from 1.95 to 1.80 ***,an alternative tectonic scenario for the Hengshan-Wutai-Fuping region involves：（i）formation of a proto-NCC at ～2.5 Ga;（ii）back-arc extension during 2.35-2.0 Ga resulting in bimodal magmatism and sedimentation in rifting basins on an Archean basem