研究者詳細 - 芳野　極

論文 - 芳野　極

分割表示 162 件中 21 - 40 件目／全件表示 >>

Exploration of the best reference material on anelastic measurement by cyclic loading under high pressure 査読

Chao Liu, Takashi Yoshino, Daisuke Yamazaki, Noriyoshi Tsujino, Hitoshi Gomi, Moe Sakurai, Youyue Zhang, Ran Wang, Longli Guan, Kayan Lau, Yoshinori Tange, Yuji Higo

High Pressure Research 42 ( 1 ) 1 - 15 2021年12月

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

Anelastic measurement by cyclic loading under high pressure has been developed by means of in situ X-ray observation at a synchrotron facility. In this method, the reference material is a key factor to precisely determine attenuation and moduli of unknown materials. We compared the performance of three types of reference materials (dense polycrystalline alumina, alumina single-crystal parallel to c-axis, and flexible graphite) under the pressure of 3 GPa and the temperature range between 1173 and 1373 K. The phase lags of strain between reference materials and samples show that the flexible graphite is less attenuated than dense polycrystalline alumina and alumina single crystal in various periods. The strain ratios show that the flexible graphite is much softer and can produce the measurable strain in the limited displacement. The flexible graphite, as reference material, is more excellent to detect the relatively lower energy dispersion of mantle minerals at high pressure.

DOI： 10.1080/08957959.2021.2013834

Web of Science

researchmap

Incorporation mechanism of Fe and Al into bridgmanite in a subducting mid-ocean ridge basalt and its crystal chemistry 査読国際誌

Akihiko Nakatsuka, Hiroshi Fukui, Seiji Kamada, Naohisa Hirao, Makio Ohkawa, Kazumasa Sugiyama, Takashi Yoshino

Scientific Reports 11 ( 1 ) 22839 - 22839 2021年12月

担当区分：最終著者記述言語：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

<title>Abstract</title>The compositional difference between subducting slabs and their surrounding lower-mantle can yield the difference in incorporation mechanism of Fe and Al into bridgmanite between both regions, which should cause heterogeneity in physical properties and rheology of the lower mantle. However, the precise cation-distribution has not been examined in bridgmanites with Fe- and Al-contents expected in a mid-ocean ridge basalt component of subducting slabs. Here we report on Mg_0.662Fe_0.338Si_0.662Al_0.338O₃ bridgmanite single-crystal characterized by a combination of single-crystal X-ray diffraction, synchrotron ⁵⁷Fe-Mössbauer spectroscopy and electron probe microanalysis. We find that the charge-coupled substitution ^AMg²⁺ + ^BSi⁴⁺ ↔ ^AFe³⁺(high-spin) + ^BAl³⁺ is predominant in the incorporation of Fe and Al into the practically eightfold-coordinated A-site and the sixfold-coordinated B-site in bridgmanite structure. The incorporation of both cations via this substitution enhances the structural distortion due to the tilting of BO₆ octahedra, yielding the unusual expansion of mean <A–O> bond-length due to flexibility of A–O bonds for the structural distortion, in contrast to mean <B–O> bond-length depending reasonably on the ionic radius effect. Moreover, we imply the phase-transition behavior and the elasticity of bridgmanite in slabs subducting into deeper parts of the lower mantle, in terms of the relative compressibility of AO₁₂ (practically AO₈) and BO₆ polyhedra.

DOI： 10.1038/s41598-021-00403-6

PubMed

researchmap

その他リンク： https://www.nature.com/articles/s41598-021-00403-6

Thermal equation of state of F-bearing superhydrous phase B (Mg10Si3O14(OH,F)4): Implications for the transportation of fluorine and water into the lower mantle 査読

Xiang Li, Yungui Liu, Ran Wang, Takashi Yoshino, Jingui Xu, Dongzhou Zhang, Tobias Grützner, Junfeng Zhang, Xiang Wu

Physics of the Earth and Planetary Interiors 106824 - 106824 2021年11月

Electrical Resistivity of Cu and Au at High Pressure above 5 GPa: Implications for the Constant Electrical Resistivity Theory along the Melting Curve of the Simple Metals 査読

IC Ezenwa, T. Yoshino

Materials 14 5476 2021年10月

Electrical conductivity of diaspore, δ-AlOOH and ε-FeOOH 査読

Ran Wang, Takashi Yoshino

American Mineralogist 106 ( 5 ) 774 - 781 2021年5月

担当区分：最終著者掲載種別：研究論文（学術雑誌）出版者・発行元：Mineralogical Society of America

<title>Abstract</title>
Electrical conductivities of diaspore (α-AlOOH), δ-AlOOH, and ε-FeOOH were measured by impedance spectroscopy with a frequency range from 10–1 to 106 Hz at pressures from 8 to 20 GPa and temperatures from 500 to 1200 K, well below the dehydration temperatures of these phases at the relevant pressures. For diaspore, the relationship between electrical conductivity and reciprocal temperature can be well fitted by the Arrhenius formula:

σ = σ 0 exp ⁡ [ − ( Δ E + P Δ V ) k T ] ,

where σ0 is the pre-exponential factor, ∆E is the activation energy, and ∆V is activation volume of 56.0 ± 1.2 S/m, 0.55 ± 0.02 eV, and 1.68 ± 0.12 cm3/mol, respectively. The electrical conductivity of diaspore decreases with increasing pressure ranging from 8 to 12 GPa by a half order of magnitude, whereas the conductivity becomes almost constant in a pressure range above 12 GPa. δ-AlOOH and ε-FeOOH show one and two orders of magnitude higher electrical conductivity than diaspore. Electrical conductivities of δ-AlOOH and ε-FeOOH, which have isostructural CaCl2-type hydroxide structure, show the nearly identical activation enthalpies (0.38 ± 0.01, 0.33 ± 0.05 eV), which are relatively lower than that of diaspore. The dominant conduction mechanism of AlOOH phases can be regarded as proton conduction. The conductivity difference between diaspore and δ-AlOOH attributes to result in the different O1H bond lengths of each phase. The reduction of O1H bond length with increasing pressure could enhance the proton migration by reducing the potential barrier, thereby raising the electrical conductivity. Small polaron conduction may contribute to the conductivity of ε-FeOOH to generate higher conductivity than δ-AlOOH. Furthermore, hydrogen bond symmetrization will also play an important role in the conductivity discrepancy of these hydrous minerals with CaCl2-type hydroxide structure. For subducted sedimentary rocks, polymorphs of AlOOH and FeOOH are representative hydrous phases. Al-rich sediments show conductivity reduction with increasing depth until phase transformation occurs because diaspore represents negative pressure dependence of conductivity. After transformation to δ-AlOOH, the conductivity will jump up around 18 GPa. If ε-FeOOH is stable above 5 GPa in an iron-rich lithology, such as banded iron formation (BIF), a high conductivity zone with positive pressure dependence could be observed to the deep lower mantle.

DOI： 10.2138/am-2021-7605

researchmap

Hydrogen diffusion mechanism in the mantle deduced from H-D interdiffusion in wadsleyite 査読

Wei Sun, Takashi Yoshino, Naoya Sakamoto, Hisayoshi Yurimoto

Earth and Planetary Science Letters 561 116815 - 116815 2021年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Elsevier BV

Classical view has interpreted deuterons in nominally anhydrous minerals (NAMs) diffuse slightly slower than protons by the Knudsen limit of root 2, whereas here we report deuteron diffusion is about 3 similar to 7 times faster than proton one in Mg2SiO4 wadsleyite based on the H-D interdiffusion couple experiments using a pair of wadsleyite single crystal at 16 GPa and 900-1300 K. Our results indicate hydrogen diffusion in wadsleyite is affected by multiple diffusion mechanisms, of which, proton (deuteron) migrating along interstitial defects is particularly efficient to separate hydrogen isotopes in crystalline network probably owing to a quantum sieving effect. The resulting diffusion-driven H/D fractionation can explain common observations of deuterium depletion of NAMs in mantle xenoliths, suggesting that MORE inclusions hosted in xenoliths are more reliable for indicating the hydrogen isotope composition of the mantle rather than the xenolithic NAMs. (C) 2021 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.epsl.2021.116815

Web of Science

researchmap

Electrical conductivity of melts: Implications for conductivity anomalies in the Earth's mantle 査読

Bao-Hua Zhang, Xuan Guo, Takashi Yoshino, Qun-Ke Xia

National Science Review 2021年4月

掲載種別：研究論文（学術雑誌）出版者・発行元：Oxford University Press (OUP)

<title>Abstract</title>
Magmatic liquids, including silicate and carbonate melts, are principal agents of mass and heat transfer in Earth and terrestrial planets, and they play a crucial role in various geodynamic processes and Earth's evolution. Electrical conductivity data of these melts elucidate the cause of electrical anomalies in Earth's interior and shed light on the melt structure. With the improvement on high-pressure experimental techniques and theoretical simulations, major progresses have been made on this front in the past several decades. This review aims to summarize recent advances in experimental and theoretical studies on the electrical conductivity of silicate and carbonate melts of different compositions and volatile contents under high temperature and pressure. The electrical conductivity of silicate melt depends strongly on temperature, pressure, water content, and the ratio of non-bridging oxygens to tetrahedral cations (NBO/T). By contrast, the electrical conductivity of carbonate melts exhibits a weak dependence on temperature and pressure due to their fully depolymerized structure. The electrical conductivity of carbonate melts is higher than that of silicate melts by at least two orders of magnitude. Water can increase electrical conductivity significantly and reduce the activation energy of silicate melts. Conversely, this effect is weak for carbonate melts. In addition, the replacement of alkali-earth elements (Ca2+ or Mg2+) with alkali elements causes a significant decrease in the electrical conductivity of carbonate melts. A distinct compensation trend is revealed for the electrical conductivity of silicate and carbonate melts under anhydrous and hydrous conditions. Several important applications of laboratory-based melt conductivity are introduced to understand the origin of high-conductivity anomalies in the Earth's mantle. Perspectives for future studies are also provided.

DOI： 10.1093/nsr/nwab064

researchmap

Martian core heat flux: Electrical resistivity and thermal conductivity of liquid Fe at Martian core P-T conditions 査読

Innocent C. Ezenwa, Takashi Yoshino

Icarus 114367 - 114367 2021年2月

Fe–Mg interdiffusion in wadsleyite and implications for water content of the transition zone 査読

Baohua Zhang, Chengcheng Zhao, Takashi Yoshino

Earth and Planetary Science Letters 554 116672 - 116672 2021年1月

Electrical resistivity of solid and liquid Pt: Insight into electrical resistivity of ε-Fe 査読

Innocent C. Ezenwa, Takashi Yoshino

Earth and Planetary Science Letters 544 116380 - 116380 2020年8月

Pressure dependence of graphitization: implications for rapid recrystallization of carbonaceous material in a subduction zone 査読

Yoshihiro Nakamura, Takashi Yoshino, Madhusoodhan Satish-Kumar

Contributions to Mineralogy and Petrology 175 ( 4 ) 2020年4月

Measurement of the Seebeck coefficient under high pressure by dual heating 査読

Takashi Yoshino, Ran Wang, Hitoshi Gomi, Yoshihisa Mori

Review of Scientific Instruments 91 ( 3 ) 035115 - 035115 2020年3月

Technique, cell assembly, and measurement of T-dependent electrical resistivity of liquid Fe devoid of contamination at P, T conditions 査読

Innocent C. Ezenwa, Takashi Yoshino

Review of Scientific Instruments 91 ( 2 ) 023903 - 023903 2020年2月

Grain boundary diffusion of W in lower mantle phase with implications for isotopic heterogeneity in oceanic island basalts by core-mantle interactions 査読

T. Yoshino, Y. Makino, T. Suzuki, T. Hirata

Earth and Planetary Science Letters 530 115887 2020年1月

Temperature-enhanced electrical conductivity anisotropy in partially molten peridotite under shear deformation 査読

B. Zhang, T. Yoshino

Earth and Planetary Science Letters 530 115922 2020年1月

Electrical Conductivity of Omphacite as a Function of Water Content and Implications for High Conductivity Anomalies in the Dabie-Sulu UHPM Belts and Tibet

Baohua Zhang, Chengcheng Zhao, Jianhua Ge, Takashi Yoshino

Journal of Geophysical Research: Solid Earth 124 ( 12 ) 12523 - 12536 2019年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Blackwell Publishing Ltd

Magnetotelluric surveys revealed high-conductivity layers in the lower crust beneath Tibet and in the shallow part of the upper mantle relevant to continental collision extending to the Dabie-Sulu ultrahigh-pressure metamorphic (UHPM) belts of eastern China, which have been interpreted by the presence of aqueous fluids/partial melts or hydrous phases. However, these explanations are not consistent with their petrological features and seismic properties. Hydrogen-bearing omphacite could be a probable candidate to explain such high-conductivity anomalies due to its high water-partitioning coefficient versus coexisting garnet in eclogite. In this study, we investigated electrical conductivities of Fe-free and Fe-bearing omphacite as a function of water content (0.005–0.122 wt.%) at 3 GPa and 500–1300 K. Our results show that water significantly enhances the electrical conductivity of omphacite, while iron facilitates conductivity by accelerating hydrogen diffusivity and lowering its activation enthalpy. Assuming a heat flow of 70 mW/m2, the high electrical anomalies observed beneath the Dabie-Sulu UHPM belts and the Tibetan Plateau can be reasonably explained by omphacite containing 0.07 wt.% water since water content higher than 0.07 wt.% in omphacite was frequently reported in naturally collected eclogite.

DOI： 10.1029/2019JB018826

Scopus

researchmap

Resistivity, Seebeck coefficient and thermal conductivity of platinum at high pressure and temperature 査読

H. Gomi, T. Yoshino

Physical Review B 100 214302 2019年12月

Fate of water in subducted hydrous sediments deduced from stability fields of FeOOH and AlOOH up to 20 GPa 査読

T. Yoshino, E. Baker, K. Duffey

Physics of the Earth and Planetary Interiors 294 106295 2019年9月

Effect of iron content on thermal conductivity of olivine with implications for cooling history of rocky planets 査読

Zhang Y, Yoshino T, Yoneda A, Osako M

Earth and Planetary Science Letters 519 109 - 119 2019年8月

H-D Interdiffusion in Single-Crystal Olivine: Implications for Electrical Conductivity in the Upper Mantle 査読

Wei Sun, Takashi Yoshino, Minami Kuroda, Naoya Sakamoto, Hisayoshi Yurimoto

Journal of Geophysical Research: Solid Earth 124 ( 6 ) 5696 - 5707 2019年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

©2019. American Geophysical Union. All Rights Reserved. Knowledge of water content and distribution in the Earth's mantle is critical to understanding the geochemical evolution and geodynamic processes of the Earth, since water can incorporate into nominally anhydrous minerals at high pressure and dramatically affect the chemical and physical properties of mantle minerals. Hydrogen diffusion controls the transport of water and electrical conductivity in the deep Earth but is not fully understood for olivine, the most abundant mineral in the upper mantle. Here we present new hydrogen self-diffusion coefficients determined from interdiffusion in H- and D-doped olivine single-crystal couples at the upper mantle conditions (3–13 GPa and 1,000–1,300 K). Present activation enthalpy for hydrogen migration is significant smaller than previous work determined within a limited measured temperature range. Parallel interdiffusion experiments with diversified water concentrations demonstrated that hydrogen diffusivity strongly accelerated by the water content in olivine. The geometric average diffusion coefficient on olivine is showed as a function of temperature and water content: (Formula presented.). Combined with the Nernst-Einstein relation, the present results can constrain the contribution of water to the electrical conductivity on olivine. It suggests that in situ conductivity measurements on hydrous olivine at low temperatures (<1,000 K) produced too low activation enthalpy to extrapolate to the higher temperatures. Comparison with previous results by conductivity measurements on single-crystal olivine suggests that the literature data except for Dai and Karato (2014) might overestimate water effect on conductivity because of heterogeneity of synthetic single crystals. Because of a change of dominant hydrogen diffusion mechanism at high temperature, this study suggests that the modeling of mantle conductivity with a high activation enthalpy from diffusion data is more trustworthy. Considering a reevaluated activation enthalpy on hydrogen diffusion and water solubility in olivine, comparisons between present conductivity model and geophysical observations suggest that hydration of olivine cannot account for extremely high conductive values (10−2–10−1 S/m) observed in the oceanic asthenosphere.

DOI： 10.1029/2019JB017576

Scopus

researchmap

　前のページ - 次のページ　

<芳野 極>

論文 - 芳野 極

<芳野　極>

論文 - 芳野　極