Tomographic evidence for a slab tear induced by fossil ridge subduction at Manila Trench, South China Sea

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	Tomographic evidence for a slab tear induced by fossil ridge subduction at Manila Trench, South China Sea
	Fan, Jian-ke 1,2; Wu, Shi-guo 1,2; Spence, George 3
刊名	INTERNATIONAL GEOLOGY REVIEW
	2015-06-11
卷号	57 期号:5-8 页码:998-1013
关键词	tomography ridge subduction Manila Trench slab tear South China Sea
英文摘要	A tomographic travel-time inversion has been applied to trace the subducted slab of the South China Sea (SCS) beneath the Manila Trench. The dataset, taken from the International Seismological Centre (1960-2008), is composed of 13,087 P-wave arrival times from 1401 regional earthquakes and 8834 from 1350 teleseismic events. The results image the different morphology of the subducted SCS slab as a high-velocity zone. The subducting angle of the slab varies along the trench: at 16 degrees N and 16.5 degrees N, the slab dips at a low angle (24 degrees~32 degrees) for 20-250km depth and at a moderate angle (50 degrees) for ~250-400km depth. At 17 degrees N, the slab dips at a low angle (32 degrees) to near 400km depth, and at 17.5 degrees N and 18 degrees N the slabs are near vertical from 70~700km depth, while at 20 degrees N the high-velocity anomalies exhibit features from horizontal abruptly to near vertical, extending to 500km depth. The dramatic steepening of the slab between 17 degrees N and 17.5 degrees N may indicate a slab tear, which is coincident with the axis of a fossil ridge within the SCS slab at around 17 degrees N. In addition, low-velocity zones in the three profiles above 300km depth may represent the formation of the slab window, induced by ridge subduction and slab tear, initiating upward mantle flow and resulting in the partial melting of the edge of the slab. The slab tear could explain the volcanic gap and geochemical difference between the extinct Miocene and Quaternary volcanoes in the Luzon Arc, the much higher heat flow around the fossil ridge, and the distribution of most of the adakites and the related porphyry Cu-Au deposits in the Luzon area. Based on the geometry and morphology of the subducted slab and certain assumptions, we calculate the initial time of ridge subduction, which implies that ridge subduction and slab tear possibly started at ~8Ma.
收录类别	SCI
语种	英语
WOS记录号	WOS:000353497400020
公开日期	2015-06-16
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/25479]
专题	海洋研究所_海洋地质与环境重点实验室
作者单位	1.Chinese Acad Sci, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 2.Chinese Acad Sci, Inst Oceanol, Qingdao 266071, Peoples R China 3.Univ Victoria, Sch Earth & Ocean Sci, Victoria, BC V8P 5C2, Canada
推荐引用方式 GB/T 7714	Fan, Jian-ke,Wu, Shi-guo,Spence, George. Tomographic evidence for a slab tear induced by fossil ridge subduction at Manila Trench, South China Sea[J]. INTERNATIONAL GEOLOGY REVIEW,2015,57(5-8):998-1013.
APA	Fan, Jian-ke,Wu, Shi-guo,&Spence, George.(2015).Tomographic evidence for a slab tear induced by fossil ridge subduction at Manila Trench, South China Sea.INTERNATIONAL GEOLOGY REVIEW,57(5-8),998-1013.
MLA	Fan, Jian-ke,et al."Tomographic evidence for a slab tear induced by fossil ridge subduction at Manila Trench, South China Sea".INTERNATIONAL GEOLOGY REVIEW 57.5-8(2015):998-1013.