The Hengshan low-angle normal fault zone: Structural and;geochronological constraints on the Late Mesozoic crustal extension in;South China

doi:10.1016/j.tecto.2013.05.013

CORC > 中国地质调查局 > 中国地质调查局 > 中国地质科学院地质力学研究所

	The Hengshan low-angle normal fault zone: Structural and;geochronological constraints on the Late Mesozoic crustal extension in;South China
	Li, Jianhua 2,3; Zhang, Yueqiao ; Dong, Shuwen 1; Su, Jinbao ; Li, Yong ; Cui, Jianjun ; Shi, Wei
刊名	TECTONOPHYSICS
	2013
卷号	606;SI SI 页码:97-115
关键词	Hengshan detachment fault SHRIMP zircon U-Pb Ar-40/Ar-39 geochronology Late Mesozoic Extensional structures South China
ISSN号	0040-1951;EI 1879-3266
DOI	10.1016/j.tecto.2013.05.013
英文摘要	We document in this paper a significant low-angle normal fault, namely the Hengshan detachment fault, which extends more than 150 km long in NNE orientation and bounds an elongated Early Cretaceous basin in Hunan Province, central South China. Detailed structural and geochronological analyses have been conducted along its southern segment, where a well exposed, similar to 3 km thick, flat ductile shear zone develops along the western margin of the Hengshan granitic massif. This zone is featured by shallow-dipping foliations of varied trend from NE to NW, which bear penetrative stretching lineations varying from NW to SW trend. Shear sense criteria indicate top-to-the-NW and top-to-the-SW motions along its northern and southern parts, respectively. Quartz c-axis orientations of mylonitic rocks from the shear zone exhibit asymmetric single or crossed girdle patterns, and the distributions of fabric point maxima suggest a simultaneous operation of basal and prism slips, indicating a deformation temperature ranging from 400 degrees C to 550 degrees C. One zircon U-Pb age of the sheared albitite and three muscovite Ar-40/Ar-39 ages of the mylonitic rocks indicate that the ductile shearing initiated at 136 Ma and lasted till 97 Ma. The zircon U-Pb dating results of five granitic samples from the Hengshan granitic pluton yield two phases of crystallization ages of 232-228 Ma and 150-151 Ma respectively, indicating two preceding magmatic events prior to the ductile shearing in the lower plate. Our structural and geochronological data allow defining the Hengshan massif as an extensional dome, rather than a metamorphic core complex as previously predicted, due to the lack of syn-tectonic plutonism and the origin of detachment fault associated with the reactivation of the inherited thrust. This study provides crucial evidence for understanding how the mid-upper crust deformed during the process of extension, which testifies to a coeval occurrence of non-coaxial deformation of the ductile flow in the middle crust and brittle faulting in the upper crust. It also sheds new insights into the timing of the regional crustal extension in South China, and permits to constrain its onset time to be ca. 136 Ma. (C) 2013 Elsevier B.V. All rights reserved.
学科主题	构造地质学
WOS关键词	METAMORPHIC CORE COMPLEXES ; ZIRCON U-PB ; C-AXIS FABRICS ; SOUTHEASTERN ; CHINA ; TECTONIC EVOLUTION ; NORTH-CHINA ; SE CHINA ; AR-40/AR-39 ; GEOCHRONOLOGY ; DEFORMATION HISTORY ; YANGTZE CRATON
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000326420900008
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40206]
专题	中国地质科学院地质力学研究所
作者单位	1.Chinese Acad Geol Sci, Inst Geomech, Beijing 100081, Peoples R China. 2.Chinese Acad Geol Sci, Beijing 100037, Peoples R China. 3.Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. 4.Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA.
推荐引用方式 GB/T 7714	Li, Jianhua,Zhang, Yueqiao,Dong, Shuwen,et al. The Hengshan low-angle normal fault zone: Structural and;geochronological constraints on the Late Mesozoic crustal extension in;South China[J]. TECTONOPHYSICS,2013,606;SI SI:97-115.
APA	Li, Jianhua.,Zhang, Yueqiao.,Dong, Shuwen.,Su, Jinbao.,Li, Yong.,...&Shi, Wei.(2013).The Hengshan low-angle normal fault zone: Structural and;geochronological constraints on the Late Mesozoic crustal extension in;South China.TECTONOPHYSICS,606;SI SI,97-115.
MLA	Li, Jianhua,et al."The Hengshan low-angle normal fault zone: Structural and;geochronological constraints on the Late Mesozoic crustal extension in;South China".TECTONOPHYSICS 606;SI SI(2013):97-115.