掲載種別：研究論文（学術雑誌）   出版者・発行元：American Geophysical Union (AGU)  

Abstract

The electrical conductivity of pure and Al/Fe‐bearing phase E was measured up to 950 K at 15 GPa using a complex impedance spectroscopy. Pure phase E shows comparable conductivity to that of phase D, and a few orders of magnitude higher than that of phase A and super‐hydrous phase B. Al‐bearing phase E does not exhibit a conductivity difference, while a certain amount of incorporated Fe prominently increases its electrical conductivity by a factor of 4. Unlike the sole substitution 2Al³⁺→Mg²⁺+Si⁴⁺ in phase D and H, H⁺ is likely involved in the substitution. Proton conduction is the dominant conduction mechanism, while small polaron conduction becomes dominant with increasing Fe content. Phase E in subducted slabs at depth of the upper transition zone cannot explain the high electrical conductivity anomalies beneath the Philippine Sea or Northeast China. Other mechanisms such as dehydration of hydrous minerals is needed to account for them.

DOI： 10.1029/2024jb029659

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.epsl.2024.118676

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掲載種別：研究論文（学術雑誌）   出版者・発行元：American Geophysical Union (AGU)  

Abstract

The local structure and density of ternary Fe‐C‐S liquid alloys have been studied using a combination of in situ X‐ray diffraction and absorption experiments between 1 and 5 GPa and 1600–1900 K. The addition of up to 12 at% of carbon (C) to Fe‐S liquid alloys does not significantly modify the structure, which is largely controlled by the perturbation to the Fe‐Fe network induced by S atoms. The liquid density determined from diffraction and/or absorption techniques allows us to build a non‐ideal ternary mixing model as a function of pressure, temperature, and composition in terms of the content of alloying light elements. The composition of the Moon's core is addressed based on this thermodynamic model. Under the assumption of a homogeneous liquid core proposed by two recent Moon models, the sulfur content would be 27–36 wt% or 12–23 wt%, respectively, while the carbon content is mainly limited by the Fe‐C‐S miscibility gap, with an upper bound of 4.3 wt%. On the other hand, if the core is partially molten, the core temperature is necessarily lower than 1850 K estimated in the text, and the composition of both the inner and outer core would be controlled by aspects of the Fe‐C‐S phase diagram not yet sufficiently constrained.

DOI： 10.1029/2022je007577

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その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2022JE007577

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media {LLC}  

DOI： 10.1007/s00269-022-01194-6

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Informa {UK} Limited  

DOI： 10.1080/08957959.2022.2032032

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