气候变化领域集成服务门户(CCPortal): How Thermochemical Piles Can (Periodically) Generate Plumes at Their Edges

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DOI	10.1029/2019JB018726
	How Thermochemical Piles Can (Periodically) Generate Plumes at Their Edges
	Heyn B.H.; Conrad C.P.; Trønnes R.G.
发表日期	2020
ISSN	21699313
卷号	125 期号:6
英文摘要	Deep-rooted mantle plumes are thought to originate from the margins of the Large Low Shear Velocity Provinces (LLSVPs) at the base of the mantle. Visible in seismic tomography, the LLSVPs are usually interpreted to be intrinsically dense thermochemical piles in numerical models. Although piles deflect lateral mantle flow upward at their edges, the mechanism for localized plume formation is still not well understood. In this study, we develop numerical models that show plumes rising from the margin of a dense thermochemical pile, temporarily increasing its local thickness until material at the pile top cools and the pile starts to collapse back toward the core-mantle boundary (CMB). This causes dense pile material to spread laterally along the CMB, locally thickening the lower thermal boundary layer on the CMB next to the pile, and initiating a new plume. The resulting plume cycle is reflected in both the thickness and lateral motion of the local pile margin within a few hundred km of the pile edge, while the overall thickness of the pile is not affected. The period of plume generation is mainly controlled by the rate at which slab material is transported to the CMB, and thus depends on the plate velocity and the sinking rate of slabs in the lower mantle. A pile collapse, with plumes forming along the edges of the pile's radially extending corner, may, for example, explain the observed clustering of Large Igneous Provinces (LIPs) in the southeastern corner of the African LLSVP around 95–155 Ma. ©2020. The Authors.
英文关键词	large igneous provinces; LLSVPs; lower mantle; mantle upwellings; plume initiation; thermochemical piles
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/187833
作者单位	Centre for Earth Evolution and Dynamics (CEED), University of Oslo, Oslo, Norway; Natural History Museum, University of Oslo, Oslo, Norway
推荐引用方式 GB/T 7714	Heyn B.H.,Conrad C.P.,Trønnes R.G.. How Thermochemical Piles Can (Periodically) Generate Plumes at Their Edges[J],2020,125(6).
APA	Heyn B.H.,Conrad C.P.,&Trønnes R.G..(2020).How Thermochemical Piles Can (Periodically) Generate Plumes at Their Edges.Journal of Geophysical Research: Solid Earth,125(6).
MLA	Heyn B.H.,et al."How Thermochemical Piles Can (Periodically) Generate Plumes at Their Edges".Journal of Geophysical Research: Solid Earth 125.6(2020).