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DOI	10.1016/j.epsl.2024.118654
	Decoupled anisotropy in the lower crust and upper mantle extracted by the Wave Gradiometry method resolves the differential deformation mechanisms beneath the northeastern Tibetan Plateau
	Dai, Yixin; Liang, Chuntao; Cao, Feihuang; Chen, Ling; Liu, Zhen; Fan, Xingli; Wang, Chaoliang
发表日期	2024
ISSN	0012-821X
EISSN	1385-013X
起始页码	633
卷号	633
英文摘要	The Tibet plateau is the ideal place to study how the lithospheres are deformed and how the materials move vertically and horizontally under the tectonic stress applied in an intracontinental collision region. To resolve the deformation and growth mechanism of the northeastern Tibetan Plateau, we constructed a 3-D azimuthally anisotropic shear-wave velocity (Vs) model by applying the recently developed Wave Gradiometry method based on the data recorded at 676 broadband seismic stations. Across the northeastern Tibetan Plateau, we found relatively weak low-velocity zones in the Qilian block and Bayan Har block at depths of 25 to 40 km, as well as decoupled anisotropies in the crust and mantle. In the northeastern Tibetan Plateau, the fast propagation directions (FPDs) in the mid-lower crust (20-60 km) are mostly NW-SE. Within the uppermost mantle (60-100 km), the FPDs beneath the Qilian block and the Qaidam block are nearly NE-SW, and the FPDs under the Bayan Har block are mostly in SE-NW. This result contradicts the lower crustal flow model, which expects the FPDs in the mid-lower crust to align with the assumed flow directions induced by topographic gradient (i.e. NWW-SEE beneath Bayan Har block and NE-SW beneath the Qilian block). On the contrary, our inverted 3D S-wave velocity and azimuthal anisotropy model could be well explained by pure shear deformation in the crust. That is, continuous pure shearing and shortening occur in the crust. Under the influence of asthenosphere material, the lithospheric mantle may move northeast. Crustal anisotropy is related to the strong shear deformation, whereas lithospheric mantle anisotropy is mainly due to the lattice-preferred orientation (LPO) of olivine associated with the mantle movement under the NE-SW compressional stress.
英文关键词	Northeastern Tibetan Plateau; Wave Gradiometry method; Azimuthal anisotropy; Pure shear deformation
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:001219215300001
来源期刊	EARTH AND PLANETARY SCIENCE LETTERS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/304896
作者单位	Chengdu University of Technology; Chinese Academy of Sciences; Institute of Geology & Geophysics, CAS
推荐引用方式 GB/T 7714	Dai, Yixin,Liang, Chuntao,Cao, Feihuang,et al. Decoupled anisotropy in the lower crust and upper mantle extracted by the Wave Gradiometry method resolves the differential deformation mechanisms beneath the northeastern Tibetan Plateau[J],2024,633.
APA	Dai, Yixin.,Liang, Chuntao.,Cao, Feihuang.,Chen, Ling.,Liu, Zhen.,...&Wang, Chaoliang.(2024).Decoupled anisotropy in the lower crust and upper mantle extracted by the Wave Gradiometry method resolves the differential deformation mechanisms beneath the northeastern Tibetan Plateau.EARTH AND PLANETARY SCIENCE LETTERS,633.
MLA	Dai, Yixin,et al."Decoupled anisotropy in the lower crust and upper mantle extracted by the Wave Gradiometry method resolves the differential deformation mechanisms beneath the northeastern Tibetan Plateau".EARTH AND PLANETARY SCIENCE LETTERS 633(2024).