气候变化领域集成服务门户(CCPortal): Thermal and magnetic evolution of a crystallizing basal magma ocean in Earth's mantle

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DOI	10.1016/j.epsl.2020.116085
	Thermal and magnetic evolution of a crystallizing basal magma ocean in Earth's mantle
	Blanc N.A.; Stegman D.R.; Ziegler L.B.
发表日期	2020
ISSN	0012821X
卷号	534
英文摘要	We present the thermochemical evolution of a downward crystallizing basal magma ocean (BMO) overlying the liquid outer core and probe its capability to dissipate enough power to generate and sustain an early dynamo. A total of 61 out of 112 scenarios for a BMO with imposed, present-day heat flux, QBMO, values of 15, 18, and 21 TW and radiogenic heat, Qr, values of 4, 8, and 12 TW fully crystallized during the age of the Earth. Most of these models are energetically capable of inducing magnetic activity for the first 1.5 Gyrs, at least, with durations extending to 2.5 Gyrs; with final core-mantle boundary (CMB) temperatures of 4400 ± 500 K -well within current best estimates for inferred temperatures. None of the models with QBMO = 12 TW achieved a fully crystallized state, which may reflect a lower bound on the present-day heat flux across the CMB. BMO-powered dynamos exhibit strong dependence on the partition coefficient of iron into the liquid layer and its associated melting-point depression for a lower mantle composition at near-CMB conditions -parameters which are poorly constrained to date. Nonetheless, we show that a crystallizing BMO is a plausible mechanism to sustain an early magnetic field. © 2020
关键词	basal magma ocean dynamo early Earth dynamo molten silicates
英文关键词	Interactive devices; Magnetism; Silicates; Core-mantle boundary; Early Earth; Magma ocean; Magnetic activity; Melting point depressions; Partition coefficient; Plausible mechanisms; Strong dependences; Heat flux; basalt; core-mantle boundary; crystallization; geodynamo; magma chamber; mantle source; partial melting; silicate; temperature effect; trace element
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/202494
作者单位	Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
推荐引用方式 GB/T 7714	Blanc N.A.,Stegman D.R.,Ziegler L.B.. Thermal and magnetic evolution of a crystallizing basal magma ocean in Earth's mantle[J],2020,534.
APA	Blanc N.A.,Stegman D.R.,&Ziegler L.B..(2020).Thermal and magnetic evolution of a crystallizing basal magma ocean in Earth's mantle.Earth and Planetary Science Letters,534.
MLA	Blanc N.A.,et al."Thermal and magnetic evolution of a crystallizing basal magma ocean in Earth's mantle".Earth and Planetary Science Letters 534(2020).