气候变化领域集成服务门户(CCPortal): Seismic Structure of a Postspreading Seamount Emplaced on the Fossil Spreading Center in the Southwest Subbasin of the South China Sea

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DOI	10.1029/2020JB019827
	Seismic Structure of a Postspreading Seamount Emplaced on the Fossil Spreading Center in the Southwest Subbasin of the South China Sea
	Zhang J.; Li J.; Ruan A.; Ding W.; Niu X.; Wang W.; Tan P.; Wu Z.; Yu Z.; Wei X.; Zhao Y.; Zhou Z.
发表日期	2020
ISSN	21699313
卷号	125 期号:10
英文摘要	Postspreading seamounts are unique seamounts built by volcanism after seafloor spreading had ceased. Limited understanding of their formation processes is mainly due to the lack of investigation. Therefore, we conducted a three-dimensional wide-angle seismic experiment in the Southwest Subbasin of the South China Sea and four profiles were acquired within the inactive spreading center over a postspreading seamount. Based on ocean bottom seismometer data, we report two-dimensional velocity structures of the Longnan seamount. Our results show that a low P wave velocity body (2.9–5.0 km/s, 4 km thick) is observed within the seamount summit, suggesting that material has extensively erupted as volcaniclastic rocks and high-porosity basalts. The extrusive/intrusive boundary is depressed beneath the seamount, indicating the absence of an intrusive core. Our results further show that the ratio of extrusive to intrusive volume is as high as 3.0 and that the accretion to the oceanic crust occurs in layer 2. Combined with an analysis of velocity structures of seamounts worldwide including seamounts in the South China Sea, we propose that the extrusive/intrusive ratio and type of crustal thickening are related to the magma supply mechanisms, and intrusive cores are more likely to be associated with a hot spot. The above analysis also suggests that the Longnan Seamount is a nonplume origin seamount and structurally different from other seamounts in the South China Sea. Ridge jumps in the South China Sea increase the duration or amount of volcanism, which could explain seamount structural differences. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	fossil spreading center; ocean bottom seismometer; postspreading magmatism; seamount structure; South China Sea; velocity structure
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/187558
作者单位	Key Laboratory of Submarine Geosciences, Ministry of Natural Resources and Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China; School of Oceanography, Shanghai Jiaotong University, Shanghai, China; School of Earth Sciences, Zhejiang University, Hangzhou, China; Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
推荐引用方式 GB/T 7714	Zhang J.,Li J.,Ruan A.,et al. Seismic Structure of a Postspreading Seamount Emplaced on the Fossil Spreading Center in the Southwest Subbasin of the South China Sea[J],2020,125(10).
APA	Zhang J..,Li J..,Ruan A..,Ding W..,Niu X..,...&Zhou Z..(2020).Seismic Structure of a Postspreading Seamount Emplaced on the Fossil Spreading Center in the Southwest Subbasin of the South China Sea.Journal of Geophysical Research: Solid Earth,125(10).
MLA	Zhang J.,et al."Seismic Structure of a Postspreading Seamount Emplaced on the Fossil Spreading Center in the Southwest Subbasin of the South China Sea".Journal of Geophysical Research: Solid Earth 125.10(2020).