Lithospheric S-wave velocity structure of west China and neighboring areas from surface wave tomography

doi:10.6038/cjg20141212

	Lithospheric S-wave velocity structure of west China and neighboring areas from surface wave tomography
	Huang Zhong-Xian 1; Li Hong-Yi 2; Xu Yi 3
刊名	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
	2014-12-01
卷号	57 期号:12 页码:3994-4004
关键词	West China Lithosphere Velocity structure Surface wave Tomography
ISSN号	0001-5733
DOI	10.6038/cjg20141212
文献子类	Article
英文摘要	We used Rayleigh wave dispersion data and the tomographic method to study the lithospheric S-wave structure in west China and neighboring areas (20 degrees N-55 degrees N, 65 degrees E-110 degrees E). The results indicate three active tectonic regions characterized by low crust/upper mantle velocities, i.e., the west Mongolia-Baikal region, Tibetan plateau, and Indo-China region. The lithosphere beneath west Mongolia is about 80 km thick, where the low velocity layer in upper mantle extends down to 300 km depth, indicating the existence of thermal activity originating from deep mantle. The upper mantle low velocity zone in the Myanmar back-arc region reaches 200 km depth, which is apparently related to the thermal/chemical activities above the eastward subducting India plate. The crust of the Tibetan plateau is as thick as 70 km; in its marginal area the thickness exceeds 50 km and varies rapidly across the plateau margin, which accords with the flat top and steep edge character of the plateau landform. The average mid-lower crust velocity of the Tibetan plateau is remarkably lower than normal continental crust; in the middle crust (depth 20 similar to 40 km) a low velocity layer with velocity reversal exists in the entire plateau. These characteristics indicate that the mid-lower crust deformation of the plateau is mainly plastic thickening and lateral flow under the northward compression of India plate. On the other hand the upper mantle structure shows distinctly different characteristics from the crust. Low velocity exists in the top of upper mantle beneath the plateau proper and the west Sichuan-Yunnan region, and the scope of this low velocity diminishes rapidly with depth: it vanishes below 100 km in west Sichuan-Yunnan, and is basically absent below 150 km in the entire plateau. The upper mantle structure of the Tibetan plateau varies significantly in EW direction. In the Karakorum-Pamir-Hindu Kush region west of 84 degrees E the northward subduction of India and the southward subduction of Asia caused magnificent high velocities in the upper mantle. Between 84 degrees E and 94 degrees E the velocity at the top of upper mantle is low, and a slab-like high velocity exists in the depth range 150,-220 km, which probably is the subducting India lithosphere with its front reaching beneath the Kunlun-Bayankala mountains. In the region north of the eastern Himalayan syntaxis the velocity in upper mantle is obviously high, which may hamper the eastward movement of upper mantle material. In the west Sichuan-Yunnan region the lithosphere thickness is similar to that of the Yangtze craton, about 180 km, but the velocity in the top of upper mantle is low. These phenomena indicate that the deformation/tectonic movement of the lithospheric mantle in the Tibetan plateau is fundamentally different from its crust.
WOS关键词	UPPER-MANTLE STRUCTURE ; TIBETAN PLATEAU ; INDIAN LITHOSPHERE ; STRUCTURE BENEATH ; CENTRAL MONGOLIA ; SOUTHERN TIBET ; CRUST BENEATH ; INVERSION ; PROPAGATION ; NOISE
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000347270700013
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/85267]
专题	中国科学院地质与地球物理研究所
通讯作者	Huang Zhong-Xian
作者单位	1.China Earthquake Adm, Inst Crustal Dynam, Beijing 100085, Peoples R China 2.China Univ Geosci, Sch Geophys & Informat Technol, Beijing 100083, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Huang Zhong-Xian,Li Hong-Yi,Xu Yi. Lithospheric S-wave velocity structure of west China and neighboring areas from surface wave tomography[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2014,57(12):3994-4004.
APA	Huang Zhong-Xian,Li Hong-Yi,&Xu Yi.(2014).Lithospheric S-wave velocity structure of west China and neighboring areas from surface wave tomography.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,57(12),3994-4004.
MLA	Huang Zhong-Xian,et al."Lithospheric S-wave velocity structure of west China and neighboring areas from surface wave tomography".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 57.12(2014):3994-4004.