气候变化领域集成服务门户(CCPortal): Clockwise rotation of the Baoshan Block due to southeastward tectonic escape of Tibetan crust since the Oligocene

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DOI	10.1093/gji/ggu009
	Clockwise rotation of the Baoshan Block due to southeastward tectonic escape of Tibetan crust since the Oligocene
	Kornfeld, Daniela; Eckert, Sabine; Appel, Erwin; Ratschbacher, Lothar; Pfaender, Joerg; Liu, Deliang; Ding, Lin
通讯作者	Kornfeld, D (通讯作者)
发表日期	2014
ISSN	0956-540X
EISSN	1365-246X
起始页码	149
结束页码	163
卷号	197 期号:1
英文摘要	Understanding the mode of deformation around the Eastern Himalayan Syntaxis (EHS) is crucial for models of Tibetan Plateau evolution. To constrain rotations and translation east of the EHS, we present new palaeomagnetic data from meta-basalt layers-possibly sills-of the Baoshan Block in western Yunnan, southeastern Tibet Plateau; the meta-basalts were either emplaced or metamorphosed to greenschist facies at similar to 30 Ma (Ar-40-Ar-39 whole rock ages). A detailed rock magnetic study-in combination with reflected and transmitted light microscopy-identifies magnetite and Ti-rich titanomagnetite as the main magnetic carriers. Using alternating field demagnetization, we separated well-clustered characteristic remanent magnetizations. A fold test indicates a syn-folding remanence acquisition, supporting an Oligocene magnetization due to evidence for regional Eocene-Oligocene shortening. The tilt corrected overall site mean direction at 30 per cent of unfolding yields declination/inclination = 042.2 degrees/47.0 degrees, corresponding to a clockwise rotation of 35.1 degrees +/- 12.7 degrees with respect to stable Eurasia. This denotes an average rotation rate of 1.17 +/- 0.42 degrees Myr(-1) since similar to 30 Ma, ranging at the lower limit of the present-day, GPS-derived rotation rates. We explain the clockwise rotation by tectonic escape of the Baoshan and the Lanping-Simao blocks along the Ailao Shan shear zone. With the onset of shearing along the Chong Shan and Gaoligong Shan shear zones, the Baoshan Block continued its southeastward escape, decoupled from the Lanping-Simao Block between these two major shear zones. Crustal flow could explain rotation and southward escape after similar to 20 Ma.
关键词	INDIA-ASIA COLLISION EASTERN HIMALAYAN SYNTAXIS THAI-MALAY BLOCK WESTERN YUNNAN SHEAR ZONE CRETACEOUS ROCKS PALEOMAGNETIC DATA DEFORMATION CHINA CONSTRAINTS
英文关键词	Palaeomagnetism applied to tectonics; Rock and mineral magnetism; Thermochronology; Asia
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000334096600010
来源期刊	GEOPHYSICAL JOURNAL INTERNATIONAL
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258301
推荐引用方式 GB/T 7714	Kornfeld, Daniela,Eckert, Sabine,Appel, Erwin,et al. Clockwise rotation of the Baoshan Block due to southeastward tectonic escape of Tibetan crust since the Oligocene[J]. 中国科学院青藏高原研究所,2014,197(1).
APA	Kornfeld, Daniela.,Eckert, Sabine.,Appel, Erwin.,Ratschbacher, Lothar.,Pfaender, Joerg.,...&Ding, Lin.(2014).Clockwise rotation of the Baoshan Block due to southeastward tectonic escape of Tibetan crust since the Oligocene.GEOPHYSICAL JOURNAL INTERNATIONAL,197(1).
MLA	Kornfeld, Daniela,et al."Clockwise rotation of the Baoshan Block due to southeastward tectonic escape of Tibetan crust since the Oligocene".GEOPHYSICAL JOURNAL INTERNATIONAL 197.1(2014).