气候变化领域集成服务门户(CCPortal): Subduction of the Indian Plate and the Nature of the Crust Beneath Western Tibet: Insights From Seismic Imaging

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DOI	10.1029/2020JB019684
	Subduction of the Indian Plate and the Nature of the Crust Beneath Western Tibet: Insights From Seismic Imaging
	Li L.; Murphy M.A.; Gao R.
发表日期	2020
ISSN	21699313
卷号	125 期号:8
英文摘要	The northward extent of subducted Indian plate is a fundamental component of hypotheses explaining deformation and magmatism within the Tibetan Plateau. Yet, these aspects of the plate are debated in west Tibet. Here we report a new three-dimensional lithospheric structure of seismic velocity and radial anisotropy under west Tibet constructed from Rayleigh and Love wave phase velocity maps at periods of 20–167 and 20–125 s, respectively. Our results show the Indian lithospheric mantle to be subhorizontally subducted under west Tibet across the Bangong-Nujiang suture to the Qiangtang terrane, as indicated by a prominent fast velocity anomaly accompanied with positive radial anisotropy (Vsh > Vsv). We find a positive spatial correlation of this result with information on the distribution of late Cenozoic potassic-adakitic rocks in western Tibet. Additionally, we show that the midcrust of west Tibet is characterized by an anomalously low shear wave velocity (3.2–3.4 km/s at ~30-km depth) and positive anisotropy, which is consistent with an estimated ~3% fraction of partial melt. We suggest that the midcrust of this region is capable of flowing and that its three-dimensional structure shows it to extend south of the Karakoram fault (KKF), a shear zone interpreted as a barrier to crustal flow. Instead, our results are consistent with the KKF embedded in weak middle crust along with several other structures that display a pattern of distributed deformation in the western portion of the Tibetan Plateau. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	Karakoram fault; middle crust; radial anisotropy; shear wave velocity; west Tibet
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187667
作者单位	School of Earth Sciences and Engineering, Guangzhou, China; Guangdong Provincial Key Lab of Geodynamics and Geohazards, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China; Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, United States
推荐引用方式 GB/T 7714	Li L.,Murphy M.A.,Gao R.. Subduction of the Indian Plate and the Nature of the Crust Beneath Western Tibet: Insights From Seismic Imaging[J],2020,125(8).
APA	Li L.,Murphy M.A.,&Gao R..(2020).Subduction of the Indian Plate and the Nature of the Crust Beneath Western Tibet: Insights From Seismic Imaging.Journal of Geophysical Research: Solid Earth,125(8).
MLA	Li L.,et al."Subduction of the Indian Plate and the Nature of the Crust Beneath Western Tibet: Insights From Seismic Imaging".Journal of Geophysical Research: Solid Earth 125.8(2020).