Structural features and deformational ages of the northern Dabashan thrust belt

作     者：Pengyuan Li Jinjiang Zhang Lei Guo Xiongying Yang 

作者机构：The Key Laboratory of Orogenic Belts and Crustal EvolutionPeking UniversityBeijing 100871China Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China 

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

年 卷 期：2012年第3卷第1期

页      面：41-49页

核心收录：

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 09[农学] 0901[农学-作物学] 

基　　金：supported by NationaI Natural Science Foundation of China(No.40821002) major project of China Petrochemical Corporation(Sinopec Group) for fundamental research(ContinentaI Tectonics and Prospects of Marine Origin Hydrocarbon Resource in The Middle-Upper Yangtze Region, Southern China,No.YPH08001-01) 

主　　题：Northern Dabashan Thrust belt Backthrust Tectonics Pop-up structure Ar-Ar geochronology 

摘      要：A large-scale pop-up structure occurs at the front of the northern Dabashan thrust belt （NDTB）, bound by the NNE-dipping Chengkou fault to the south, and the SSW-dipping Gaoqiao fault to the north. The pop-up structure shows different features along its strike as a direct reflection of the intensity of tectonic＂ activity. To the northwest, the structure is characterized by a two-directional thrust system forming a positive flower-like structure. In contrast, the southeastern part is composed of the vertical Chengkou fault and a series of N-directed backthrusts, showing a semi-flower-like structure. We present results from Ar-Ar dating of syntectonic microthermal metamorphic sericite which show that the Chengkou fault experienced intense deformation during the mid-Mesozoic Yanshanian epoch （about 143.3 Ma）, causing rapid uplift and thrusting of the northern Dabashan thrust belt. During the propagation of this thrust, a series of backthrusts formed because of the obstruction from the frontier of Dabashan thrust belt, leading to the development of the pop-up structure.