Structural features and deformational ages of the northern Dabashan thrust belt

详细信息    查看全文

• 作者：Pengyuan Li^a ; Jinjiang Zhang^a ; ^{zhjj@pku.edu.cn} ; Lei Guo^b ; Xiongying Yang^b
• 关键词：Northern Dabashan ; Thrust belt ; Backthrust ; Tectonics ; Pop-up structure ; Ar-Ar geochronology
• 刊名：Geoscience Frontiers
• 出版年：2012
• 出版时间：January, 2012
• 年：2012
• 卷：3
• 期：1
• 页码：41-49
• 全文大小：1803 K

文摘

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.