气候变化领域集成服务门户(CCPortal): The Electrical Conductivity of Liebermannite: Implications for Water Transport Into the Earth's Lower Mantle

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DOI	10.1029/2020JB020094
	The Electrical Conductivity of Liebermannite: Implications for Water Transport Into the Earth's Lower Mantle
	Manthilake G.; Schiavi F.; Zhao C.; Mookherjee M.; Bouhifd M.A.; Jouffret L.
发表日期	2020
ISSN	21699313
卷号	125 期号:8
英文摘要	Liebermannite (KAlSi3O8) is a principal mineral phase expected to be thermodynamically stable in deeply subducted continental and oceanic crusts. The crystal structure of liebermannite exhibits tunnels that are formed between the assemblies of double chains of edge-sharing (Si, Al) O6 octahedral units, which act as a repository for large incompatible alkali ions. In this study, we investigate the electrical conductivity of liebermannite at 12, 15, and 24 GPa and temperature of 1500 K to track subduction pathways of continental sediments into the Earth's lower mantle. Further, we looked at whether liebermannite could sequester incompatible H2O at deep mantle conditions. We observe that the superionic conductivity of liebermannite due to the thermally activated hopping of K+ ions results in high electrical conductivity of more than 1 S/m. Infrared spectral features of hydrous liebermannite indicate the presence of both molecular H2O and hydroxyl (OH−) groups in its crystal structure. The observed high electrical conductivity in the mantle transition zone beneath Northeastern China and the lower mantle beneath the Philippine Sea can be attributed to the subduction pathways of continental sediments deep into the Earth's mantle. While major mineral phases in pyrolitic compositions are almost devoid of H2O under lower mantle conditions, our study demonstrates that liebermannite could be an important host of H2O in these conditions. We propose that the relatively high H2O contents of ocean island basalts derived from deep mantle plumes are primarily related to deeply subducted continental sediments, in which liebermannite is the principal H2O carrier. © 2020. American Geophysical Union. All Rights Reserved.
英文关键词	continental sediments; electrical conductivity; liebermannite; mantle plumes; ocean island basalts; water transport
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/187702
作者单位	Laboratoire Magmas et Volcans, CNRS, IRD, OPGC, Université Clermont Auvergne, Clermont-Ferrand, France; Earth Materials Laboratory, Department of Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, United States; Laboratoire des Matériaux et du Génie Physique, Grenoble, France
推荐引用方式 GB/T 7714	Manthilake G.,Schiavi F.,Zhao C.,et al. The Electrical Conductivity of Liebermannite: Implications for Water Transport Into the Earth's Lower Mantle[J],2020,125(8).
APA	Manthilake G.,Schiavi F.,Zhao C.,Mookherjee M.,Bouhifd M.A.,&Jouffret L..(2020).The Electrical Conductivity of Liebermannite: Implications for Water Transport Into the Earth's Lower Mantle.Journal of Geophysical Research: Solid Earth,125(8).
MLA	Manthilake G.,et al."The Electrical Conductivity of Liebermannite: Implications for Water Transport Into the Earth's Lower Mantle".Journal of Geophysical Research: Solid Earth 125.8(2020).