气候变化领域集成服务门户(CCPortal): Slab dehydration in warm subduction zones at depths of episodic slip and tremor

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DOI	10.1016/j.epsl.2020.116601
	Slab dehydration in warm subduction zones at depths of episodic slip and tremor
	Condit C.B.; Guevara V.E.; Delph J.R.; French M.E.
发表日期	2020
ISSN	0012821X
卷号	552
英文摘要	Non-volcanic tremor (NVT) and episodic slow slip events (SSEs) have been observed below the seismogenic zone of relatively warm subduction zones for the past 20 years. Geophysical and geologic observations show that this portion of the subduction interface is fluid-rich, and many models for these slip behaviors necessitate high pore fluid pressures. However, whether these fluids are sourced from local dehydration reactions in particular lithologies, or require up-dip transport from greater depths is not known. We present thermodynamic models of the petrologic evolution of four lithologies typical of the plate interface (average MORB, seafloor altered MORB, hydrated depleted MORB mantle, and metapelite) along predicted plate boundary pressure–temperature (P-T) paths at several warm subduction segments where NVT and SSEs are observed at depths between 25-65 km. The models suggest that 1-2 wt% H2O is released at the depths of NVT/SSEs in Jalisco-Colima, Guerrero, Cascadia, and Shikoku due to punctuated dehydration reactions within MORB, primarily through chlorite and/or lawsonite breakdown. These reactions produce sufficient in-situ fluid across a narrow P-T range to cause high pore fluid pressures at NVT/SSE depths. Dehydration of hydrated peridotite is minimal at these depths for most margins, and metapelite releases H2O (<1.5 wt%) gradually over a wide depth range compared to MORB. We posit that punctuated dehydration of oceanic crust provides the dominant source of fluids at the base of the seismogenic zone in these warm subduction zones, and up-dip migration of fluids from deeper in the subduction zone is not required. © 2020 The Authors
关键词	dehydration slow slip subduction tremor
英文关键词	Dehydration; Hydration; Seismographs; Silicate minerals; Dehydration reactions; Depleted MORB mantles; Episodic slow slips; Hydrated peridotites; Non-volcanic tremors; Pore fluid pressure; Subduction interface; Thermodynamic model; Transport properties; lithology; metapelite; oceanic crust; P-T conditions; peridotite; petrology; plate boundary; slip; subduction zone
语种	英语
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/202549
作者单位	University of Washington, Seattle, WA, United States; Rice University, Houston, TX, United States; Amherst College, Amherst, MA, United States; University of Oregon, Eugene, OR, United States; Purdue University, Lafayette, ID, United States
推荐引用方式 GB/T 7714	Condit C.B.,Guevara V.E.,Delph J.R.,et al. Slab dehydration in warm subduction zones at depths of episodic slip and tremor[J],2020,552.
APA	Condit C.B.,Guevara V.E.,Delph J.R.,&French M.E..(2020).Slab dehydration in warm subduction zones at depths of episodic slip and tremor.Earth and Planetary Science Letters,552.
MLA	Condit C.B.,et al."Slab dehydration in warm subduction zones at depths of episodic slip and tremor".Earth and Planetary Science Letters 552(2020).