Search Results 1-20 of 291

  • Origin of ocean island basalts in the West African passive margin without mantle plume involvement

    Belay Iyasu Getachew , Tanaka Ryoji , Kitagawa Hiroshi , Kobayashi Katsura , Nakamura Eizo

    … The geochemical variabilities in intraplate basalts (IB) from the West African passive margin (WAPM) region, have generally been employed to indicate the presence of recycled materials in an associated upwelling mantle plume. … However, the absence of time-progressive linear hotspot tracks in WAPM-IB make it difficult to explain their genesis solely by the mantle plume hypothesis. …

    Nature Communications 10(1), 3022, 2019-07

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  • Tectonics of boninites: Subduction initiation and mantle evolution  [in Japanese]

    UMINO Susumu

    … Homogeneous glass inclusions in chrome spinel of boninite from Ogasawara, Guam and Oman Ophiolite preserve at least three primary magmas followed by discrete fractionation paths designated high-silica, low-silica, and ultralow-silica boninites, in decreasing degree of source mantle depletion.</p><p> The <i>T-P</i> …

    Japanese Magazine of Mineralogical and Petrological Sciences 48(2), 63-75, 2019

    J-STAGE 

  • An improved and simple experimental technique for modeling thermal convection in science class using frozen starch syrup and localized heating  [in Japanese]

    山崎 博史 , 藤井 潤 , 兼重 堅志郎 , 妹尾 息吹 , 吉冨 健一

    Mantle convection, which refers to the thermal convection in the mantle, is the driving force for plate tectonics. … Therefore, a heat convection modeling experiment was proposed for secondary school-level science students so that they can visualize and comprehend mantle convection. …

    学校教育実践学研究 25, 45-50, 2019

    IR  DOI 

  • On destruction of a thermally stable layer by compositional convection in the earth's outer core

    Takehiro Shin Ichi , Sasaki Youhei

    … We discuss destruction of a thermally stable layer in the upper part of the Earth's outer core by compositional convection excited at the inner core boundary. … We propose to use the radial distribution of power induced by thermal and compositional buoyancy (rate of kinetic energy production) as a measure of occurrence of thermal and compositional convection. …

    Frontiers in Earth Science (6), 2018-11-02

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  • Why does substorm-associated auroral surge travel westward?

    Ebihara Y , Tanaka T

    … When the interplanetary magnetic field turns southward, a persistent dynamo appears in the cusp/mantle region, driving the two-cell magnetospheric convection. …

    Plasma Physics and Controlled Fusion 60(1), 2018-01

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  • Chemical evolution of the earth's mantle over 3.5 Gyr  [in Japanese]

    Kimura Jun-Ichi

    … <p>Earth's mantle formed at 4.6 Ga and evolved through the Hadean magma ocean stage and subsequent plate tectonics stage since 3.5 Ga. … Mantle convection driven by the internal heat is the major driving force of the plate tectonics with considerable tectonic roles of both oceanic and continental plates formed at mid-ocean ridges (MOR) and subduction zones (SZ), respectively. …

    Chikyukagaku 52(1), 29-53, 2018

    J-STAGE 

  • Energy flow exciting field-aligned current at substorm expansion onset

    Ebihara Y. , Tanaka T.

    … Our simulations show that the cusp/mantle region transmits electromagnetic energy to almost the entire region of the magnetosphere when the interplanetary magnetic field is southward. … Integral curve of the Poynting flux shows a spiral moving toward the ionosphere, probably suggesting the pathway of electromagnetic energy from the cusp/mantle dynamo to the ionosphere. …

    Journal of Geophysical Research: Space Physics 122(12), 12,288-12,309, 2017-12

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  • Electrical conductivity of old oceanic mantle in the northwestern Pacific I: 1-D profiles suggesting differences in thermal structure not predictable from a plate cooling model

    Baba Kiyoshi , Tada Noriko , Matsuno Tetsuo , Liang Pengfei , Li Ruibai , Zhang Luolei , Shimizu Hisayoshi , Abe Natsue , Hirano Naoto , Ichiki Masahiro , Utada Hisashi

    … Seafloor magnetotelluric (MT) experiments were recently conducted in two areas of the northwestern Pacific to investigate the nature of the old oceanic upper mantle. … The areas are far from any tectonic activity, and "normal" mantle structure is therefore expected. … To explain the observed spatial variation, dynamic processes must be introduced, such as influence of the plume associated with the formation of the Shatsky Rise, or spatially non-uniform, small-scale convection in the asthenosphere. …

    Earth, Planets and Space (69), 111, 2017-08-15

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  • Supercontinent cycle and thermochemical structure in the mantle: Inference from two-dimensional numerical simulations of mantle convection  [in Japanese]

    Kameyama Masanori , Harada Akari

    Annual Meeting of the Geological Society of Japan 2017(0), 298, 2017

    J-STAGE 

  • Constraints on Primordial Noble Gas Reservoir Deep in the Earth by High-Pressure and High-Temperature Experiments  [in Japanese]

    SUMINO Hirochika , KISHI Satoshi , NOMURA Ryuichi , MIBE Kenji , TATENO Shigehiko , KAGI Hiroyuki

    … Noble gas isotopes have been a strong argument for the presence of primordial reservoir in the mantle, which has been isolated from the mantle convection throughout the Earth's history. … However, recent understanding of mantle dynamics has revealed difficulty with the isolation within the mantle. …

    The Review of High Pressure Science and Technology 27(4), 266-277, 2017

    J-STAGE 

  • Magmatism, mantle convection and whole Earth dynamics  [in Japanese]

    Iwamori Hikaru

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN 2017(0), 13-13, 2017

    J-STAGE 

  • Experimental geophysics—measurement of physical and chemical properties of major mantle minerals at high pressures and temperatures  [in Japanese]

    KATSURA Tomoo

    … In this article, I review four topics of my past researches that are intended to bring new insights about structure and dynamics of the Earth's mantle. … This shallow slope suggests that seismically observed depression of the 600-km discontinuity under subduction zones cannot be explained by a temperature effect only, and that the 660-km discontinuity will not be a barrier of mantle convection. …

    Japanese Magazine of Mineralogical and Petrological Sciences 46(1), 1-14, 2017

    J-STAGE 

  • Role of subduction zones and ocean ridges on mantle evolution  [in Japanese]

    Kimura Jun―Ichi

    … Our models of differs from previous works by being internally consistent with geodynamic models of modern arcs and ocean ridges that successfully explains magma geneses and include element fluxes in the residual slab and mantle components. … Estimated mantle potential temperature (Tp) was ~1650 °C at 3.5?2.0 Ga and gradually decreased to ~1300 °C today. …

    Abstracts of Annual Meeting of the Geochemical Society of Japan 63(0), 161, 2016

    J-STAGE 

  • Formation of oceans and continents on the Earth  [in Japanese]

    Iizuka Tsuyoshi

    … The hydrogen isotope data for meteorites and mantle-derived terrestrial samples suggest that proto-planets and planetesimals, that accreted to form the Earth, could acquire water from solar nebular and water-rich materials delivered from outer Solar System, respectively. … The infant solid Earth would be characterized by the stagnant-lid convection regime. … Meanwhile, radiogenic heat generation induced vigorous mantle plumes and stagnant plates had been cooled and hydrated. …

    Chikyukagaku 50(3), 121-133, 2016

    J-STAGE 

  • Plate Subduction and Arc Magmatism(<Special Section>The 60th Anniversary of VSJ "Latest Advances and Future Perspectives in Volcanology")  [in Japanese]

    NAKAJIMA Junichi

    … The active processes -brittle deformation, metamorphism, convection and volcanism- beneath volcanic arcs or continental margins are all linked with fluids derived from subducting oceanic plates. … Here I review recent geophysical observations in subduction zones and organize our thoughts on ongoing magmatic processes, focusing on a low-velocity, high-attenuation, and low-resistivity zone in the mantle wedge as an indicator of melt migration paths. …

    BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN 61(1), 23-36, 2016

    J-STAGE 

  • Mantle Convection and Whole Earth Dynamics(<Special Section>The 60th Anniversary of VSJ "Latest Advances and Future Perspectives in Volcanology")  [in Japanese]

    IWAMORI Hikaru

    … Earth's mantle constitutes the largest sub-system of the whole Earth system, involving 70% of the total mass, ~80% of the heat capacity, and more than 50% of the internal heat generation by radioactive decay. …

    BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN 61(1), 1-22, 2016

    J-STAGE 

  • Formation of Chemical Variations in Magma Generation of Igneous Rocks  [in Japanese]

    小出 良幸

    … In this paper, the factors in their chemical diversity were considered from the solid (mantle or source materials) to formation of a magma. … In the processes of source materials, a little chemical differentiation generates mantle end-members with time effect. … The mantle end-members were expanding chemical diversity by mechanical mixing with mantle convection. …

    札幌学院大学人文学会紀要 = Journal of the Society of Humanities (98), 1-39, 2015-10

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  • Development of Advanced Simulation Methods for Solid Earth Simulations

    古市 幹人 , 宮腰 剛広 , 陰山 聡 , 亀山 真典 , 大野 暢亮 , 中川 貴司 , 横井 研介 , 西浦 泰介

    Annual report of the earth simulator, 83-87, 2015-04

  • Numerical Simulations of Geodynamo and Liquid Metal Convection

    浜野 洋三 , 高橋 太 , 柳澤 孝寿

    Annual report of the earth simulator, 67-71, 2015-04

  • Thermal and chemical evolution of the subarc mantle revealed by spinel-hosted melt inclusions in boninite from the Ogasawara (bonin) Archipelago, Japan

    Umino Susumu , Kitamura Keitaro , Kanayama Kyoko , Tamura Akihiro , Sakamoto Naoya , Ishizuka Osamu , Arai Shoji

    … The onset of the Pacific slab subduction at 52 Ma forced upwelling of depleted mid-oceanic ridge basalt mantle (DMM) to yield proto-arc basalt (PAB). … Meanwhile, convection within the mantle wedge brought the less-depleted residue of PAB and DMM into the region fluxed by slab fluids, which melted to yield the less-depleted low-Si boninite at 45 Ma, and fertile arc basalts, respectively. …

    Geology 43(2), 151-154, 2015-02-01

    IR 

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