Exhumation of high-pressure metamorphic terrane at the crustal levels in the Tongbai area, central China

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	Exhumation of high-pressure metamorphic terrane at the crustal levels in the Tongbai area, central China
	Cui, JJ (Cui JianJun); Hu, JM (Hu JianMin); Liu, XC (Liu XiaoChun)
刊名	ACTA PETROLOGICA SINICA
	2009
卷号	25 期号:9 页码:2165-2176
关键词	Tongbai complex Ductile shear zone lip metamorphic terrane Exhumation mechanism
ISSN号	1000-0569
英文摘要	The Tongbai complex is situated at the junction between the Qinling and Dabie orogens. On the two sides of the complex, there are two eclogite-bearing high-pressure (HP) metamorphic belts stretching from NWW to SEE. The issue concerning formation process and special structural relationship between the Tongbai complex and HP metamorphic belts have a strong appeal to geologists. This paper demonstrates that the so-called 'Tongbai complex' is dominated by Early Cretaceous granitic gneisses, with a number of Triassic medium- to high-grade metamorphic rocks. Two ductile shear zones, which formed at 131 Ma, occur alone the southern and northern boundaries of the complex. The strike-slip directions of the shear zones are opposite; the southern boundary is a dextral ductile shear zone, and the northern boundary is a sinistral ductile one. The mylonitic foliations dip to NNE in the northern shear zone, and to SSW in the southern shear zone. In the ductile shear zones as well as the inner part of the Tongbai complex, the stretching lineations invariably dip toward SEE. On the eastern end of the complex, a south-north stretching thrust ductile shear zone occurs, in which low-angle mylonitic foliations dip toward SEE and lineations on the foliations also plunge toward SEE. These dynamic features indicate that the eastern metamorphic terrane thrusted onto the Tongbai complex with a direction of about 295 degrees similar to 310 degrees. Therefore, the Tongbai complex is actually surrounded by a huge ductile shear zone streching alone the orogen. The deformation characteristics in the shear zone and the inner part of the Tongbai complex suggest a low-angle exhumation for the HP metamorphic terrane from the cast to the west along the orogen during the Early Cretaceous, which led to the HP metamorphic rocks being exhumed to the Earth ' s Surface from the crustal levels. Thus, the present structural observation is very important for understanding the mechanism of late exhumation of the HP/ UHP metamorphic terrane from the Tongbai-Dabie-Sulu region.
学科主题	变质岩岩石学
WOS关键词	EAST-CENTRAL CHINA ; ULTRAHIGH-PRESSURE ; DABIE MOUNTAINS ; U-PB ; COOLING HISTORY ; CONTINENTAL-CRUST ; TECTONIC EVOLUTION ; COLLISION BELT ; SOUTH-KOREA ; ROCKS
WOS研究方向	Geology
语种	中文
出版者	SCIENCE CHINA PRESS
WOS记录号	WOS:000270044500011
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/39057]
专题	中国地质调查局
作者单位	Chinese Acad Geol Sci, Inst Geomech, Beijing 100081, Peoples R China
推荐引用方式 GB/T 7714	Cui, JJ ,Hu, JM ,Liu, XC . Exhumation of high-pressure metamorphic terrane at the crustal levels in the Tongbai area, central China[J]. ACTA PETROLOGICA SINICA,2009,25(9):2165-2176.
APA	Cui, JJ ,Hu, JM ,&Liu, XC .(2009).Exhumation of high-pressure metamorphic terrane at the crustal levels in the Tongbai area, central China.ACTA PETROLOGICA SINICA,25(9),2165-2176.
MLA	Cui, JJ ,et al."Exhumation of high-pressure metamorphic terrane at the crustal levels in the Tongbai area, central China".ACTA PETROLOGICA SINICA 25.9(2009):2165-2176.