气候变化领域集成服务门户(CCPortal): K/U of the MORB Source and Silicate Earth

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DOI	10.1029/2020JB020245
	K/U of the MORB Source and Silicate Earth
	Farcy B.; Arevalo R.; Jr.; McDonough W.F.
发表日期	2020
ISSN	21699313
卷号	125 期号:12
英文摘要	Potassium (K) informs on the radiogenic heat production, atmospheric composition, and volatile element depletion of the Earth and other planetary systems. Constraints on the abundance of K in the Earth, Moon, and other rocky bodies have historically hinged on K/U values measured in planetary materials, particularly comparisons of the continental crust and mid-ocean ridge basalts (MORBs), for developing compositional models of the bulk silicate Earth (BSE). However, a consensus on the most representative K/U value for global MORB remains elusive despite numerous studies. Here, we statistically analyze a critical compilation of MORB data to determine the K/U value of the MORB source. Covariations in the log-normal abundances of K and U establish that K is 3–7 times less incompatible than U during melting and/or crystallization processes, enabling inverse modeling to infer the K/U of the MORB source region. These comprehensive data have a mean K/U for global MORB = 13,900 ± 200 (2σm; n = 4,646), and define a MORB source region with a K/U between 14,000 and 15,500, depending on the modeled melting regime. However, this range represents strictly a lower limit due to the undefined role of fractional crystallization in these samples and challenges preserving the signatures of depleted components in the MORB mantle source. This MORB source model, when combined with recent metadata analyses of ocean island basalt (OIB) and continental crust, suggests that the BSE has a K/U value >12,100 and contains >260 × 10−6 kg/kg K, resulting in a global production of ∼3.5 TW of radiogenic heat today and 1.5 × 1017 kg of 40Ar over the lifetime of the planet. ©2020. The Authors.
英文关键词	mantle; MORB; radiogenic
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/187483
作者单位	Department of Geology, University of Maryland, College Park, MD, United States; Department of Earth Sciences and Research Center for Neutrino Science, Tohoku University, Sendai, Japan
推荐引用方式 GB/T 7714	Farcy B.,Arevalo R.,Jr.,et al. K/U of the MORB Source and Silicate Earth[J],2020,125(12).
APA	Farcy B.,Arevalo R.,Jr.,&McDonough W.F..(2020).K/U of the MORB Source and Silicate Earth.Journal of Geophysical Research: Solid Earth,125(12).
MLA	Farcy B.,et al."K/U of the MORB Source and Silicate Earth".Journal of Geophysical Research: Solid Earth 125.12(2020).