DOI: 10.1016/j.epsl.2017.12.032
Scopus记录号: 2-s2.0-85039734146
论文题名: Supercritical fluid in the mantle transition zone deduced from H–D interdiffusion of wadsleyite
作者: Sun W. ; Yoshino T. ; Sakamoto N. ; Yurimoto H.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 484 起始页码: 309
结束页码: 317
语种: 英语
英文关键词: electrical conductivity
; H–D interdiffusion
; mantle transition zone
; supercritical fluid
; wadsleyite
Scopus关键词: Effluent treatment
; Electric conductivity
; Single crystals
; Supercritical fluids
; Distribution of water
; Effective diffusion
; Electrical conductivity
; Electrical conductivity measurements
; Geochemical evolution
; Mantle transition zone
; Self-diffusion coefficients
; Wadsleyite
; Diffusion in liquids
; diffusion
; electrical conductivity
; geochemistry
; mantle convection
; mantle structure
; supercritical flow
; transition zone
; wadsleyite
英文摘要: Knowledge of the distribution of water in the Earth's mantle is key to understanding the mantle convection and geochemical evolution of the Earth. As wadsleyite and ringwoodite can incorporate large amounts of water in their crystal structures, proton conduction has been invoked to account for the widespread conductive anomalies observed in the mantle wedge, where descending slab stagnates at the transition zone. However, there is a lot of controversy on whether proton conduction by itself is able to explain such anomalies, because of large discrepancy in the extent of the water effect deduced from previous electrical conductivity measurements on hydrous polycrystalline wadsleyite and ringwoodite. Here we report the hydrogen self-diffusion coefficient obtained from H–D interdiffusion experiments in wadsleyite single-crystal couples. Our results demonstrate that the effect of water on the electrical conductivity of wadsleyite is limited and hydrous wadsleyite by itself is unable to explain conductive anomalies in the transition zone. In contrast, the expected hydrogen effective diffusion does not allow the wide propagation of water between the stagnant slab and surrounding mantle, probably leading to persistence of local water saturation and continuous release of supercritical fluids at the stagnant slab roof on geological time scales. This phenomenon provides an alternative explanation for both the high-conductivity and seismic-velocity anomalies observed in the mantle wedge at the transition-zone depth. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110061
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Geodynamics Research Center, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; Institute for Study of the Earth's Interior, Okayama University, Misasa, Tottori 682-0193, Japan; Isotope Imaging Laboratory, Creative Research Institution, Hokkaido University, Sapporo, 001-0021, Japan; Department of Natural History Sciences, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
Recommended Citation:
Sun W.,Yoshino T.,Sakamoto N.,et al. Supercritical fluid in the mantle transition zone deduced from H–D interdiffusion of wadsleyite[J]. Earth and Planetary Science Letters,2018-01-01,484