气候变化领域集成服务门户(CCPortal): Cold Plumes Initiated by Rayleigh-Taylor Instabilities in Subduction Zones, and Their Characteristic Volcanic Distributions: The Role of Slab Dip

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DOI	10.1029/2020JB019814
	Cold Plumes Initiated by Rayleigh-Taylor Instabilities in Subduction Zones, and Their Characteristic Volcanic Distributions: The Role of Slab Dip
	Ghosh D.; Maiti G.; Mandal N.; Baruah A.
发表日期	2020
ISSN	21699313
卷号	125 期号:8
英文摘要	Dehydration melting in subduction zones often produces cold plumes, initiated by Rayleigh-Taylor instabilities in the buoyant partially molten zones lying above the dipping subducting slabs. We use scaled laboratory experiments to demonstrate how the slab dip (α) can control the evolution of such plumes. For α > 0°, Rayleigh-Taylor instabilities evolve as two orthogonal waves, one trench perpendicular with wavelength λL and the other one trench parallel with wavelength λT (λT > λL). We show that two competing processes, (1) λL-controlled updip advection of partially molten materials and (2) λT/λL interference, determine the modes of plume growth. The λT/λL interference gives rise to an areal distribution of plumes (Mode 1), whereas advection leads to a linear distribution of plumes (Mode 2) at the upper fringe of the partially molten layer. The λT wave instabilities do not grow when α exceeds a threshold value (α* = 30°). For α > α, λL-driven advection takes the control to produce exclusively Mode 2 plumes. We performed a series of 2-D and 3-D computational fluid dynamics simulations to test the criticality of slab dip in switching the Mode 1 to Mode 2 transition at α. We discuss the effects of viscosity ratio (R) and the density contrast (Δρ) between the source layers and ambient mantle, source layer thickness (Ts), and slab velocity (Us) on the development of cold plumes. Finally, we discuss the areal versus linear distributions of volcanoes from natural subduction zones as possible examples of Mode 1 versus Mode 2 plume products. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	arc volcanism; gravity instability; modes of plume ascent; partial melt advection; subduction plumes; wave interference
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/187677
作者单位	Department of Geological Sciences, Jadavpur University, Kolkata, India; Department of Geology, Cotton University, Guwahati, India
推荐引用方式 GB/T 7714	Ghosh D.,Maiti G.,Mandal N.,et al. Cold Plumes Initiated by Rayleigh-Taylor Instabilities in Subduction Zones, and Their Characteristic Volcanic Distributions: The Role of Slab Dip[J],2020,125(8).
APA	Ghosh D.,Maiti G.,Mandal N.,&Baruah A..(2020).Cold Plumes Initiated by Rayleigh-Taylor Instabilities in Subduction Zones, and Their Characteristic Volcanic Distributions: The Role of Slab Dip.Journal of Geophysical Research: Solid Earth,125(8).
MLA	Ghosh D.,et al."Cold Plumes Initiated by Rayleigh-Taylor Instabilities in Subduction Zones, and Their Characteristic Volcanic Distributions: The Role of Slab Dip".Journal of Geophysical Research: Solid Earth 125.8(2020).