2006 Fiscal Year Final Research Report Summary
Experimental study on the melting relation of silicate under the lowermost mantle condition
| Project/Area Number |
16340164
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | Osaka University (2006)
Tohoku University (2004-2005) |
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Principal Investigator |
KONDO Tadashi Osaka University, Graduate School of Science, Professor, 大学院理学研究科, 教授 (20252223)
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| Co-Investigator(Kenkyū-buntansha) |
OHTANI Eiji Tohoku Univ., Graduate School of Science, Professor, 大学院理学研究科, 教授 (60136306)
SUZUKI Akio Tohoku Univ., Graduate School of Science, Assistant Professor, 大学院理学研究科, 助手 (20281975)
TERASAKI Hidenori Tohoku Univ., Graduate School of Science, Assistant Professor, 大学院理学研究科, 助手 (50374898)
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| Project Period (FY) |
2004 – 2006
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| Keywords | diamond anvil cell / laser heating / core-mantle reaction synchrotron / synchrotron / core |
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| Research Abstract |
In this research project, we investigated the phase relation of the minerals under the lowermost mantle condition and the chemical reaction between those minerals and molten iron up to the condition corresponding to the earth's core-mantle boundary. For realizing such extreme conditions, we newly designed a symmetrical diamond anvil cell with a wide conical window for laser-heating and optical spectroscopy. The laser-heating system was also refined for stable heating and optimal temperature measurement from the hot sample by a spectroradiometric method. Experiments were performed using these techniques at SPring-8 and Photon Factory for in-situ X-ray diffraction measurements at high P-T, and also at laboratory for recovery runs to check the quenched samples. Thanks for the recent advances in micro-processing technologies such as laser cutting, focused ion beam, we successfully prepared the thin section of the recovered samples for analytical transmission electron microscopy. Finally we
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obtained the following results. (1) The chemical reaction between molten iron and perovskite and post-perovskite phase and wetting property at the core-mantle boundary condition was examined, and silicon and oxygen turned to be important candidates as light elements in the outer core. The wetting angle between post-perovskite phase and molten iron was slightly higher than the critical angle of 60°, which means 2wt% of the core material can be trapped in the D" layer. (2) Magnesiowustite is the heaviest minerals overall the mantle based on the iron partitioning experiments between magnesium oxide and silicate perovskite and post-perovskite phase. No evidence for the effect of a high-spin to low-spin transition was found in these minerals. (3) Potassium can be dissolved into molten iron significantly at core-mantle boundary condition, and the element may work as a heat source in the core. (4) The hydrous mineral, delta-AIOOH, has a wide stability field over 100GPa and 2000K, therefore this phase at relatively low temperature condition in descending slab possibly survive to the lowermost mantle to supply the water to core-mantle boundary. (5) Potassium bearing silicate with post-hollandite structure can be stably exist at the lowermost mantle condition. Less
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Research Products
(22 results)
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[Journal Article] Interaction between iron and post-perovskite at core-mantle boundary and core signature in plume source region2006
Author(s)
Sakai, T., Kondo, T., Ohtani, E., Terasaki, H., Endo, N., Kuba, T., Suzuki, T., Kikegawa, T.
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Journal Title
Geophys.Res.Lett. 33, L15317, doi:10.1029/2006 GL026868
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Partitioning of potassium between iron and silicate at the core-mantle boundary2006
Author(s)
Hirao, N., Ohtani, E., Kondo, T., Endo, N., Kuba, T., Suzuki, T., Kikegawa, T.
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Journal Title
Geophys.Res.Lett. 33, L08303, doi:10.1029/2005 GL05324
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Fe-Mg partitioning between (Mg, Fe)SiO_3 post-perovskite, perovskite, and magnesiowstite in the Earth's lower mantle2005
Author(s)
Kobayashi, Y., Kondo, T., Ohtani E., Hirao, N., Miyajima, N., Yagi, T., Nagase, N., Kikegawa, T.
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Journal Title
Geophys.Res.Lett. 32, L19301, doi:10.1029/2005 GL023257
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Formation of metastable cubic-perovskite in high pressure phase transformation of Ca(Mg, Fe, Al)Si_20_62005
Author(s)
Asahara, Y., Ohtani, E., Kondo, T., Kubo, T., Miyajima, N., Nagase, T., Fujino, K., Yagi, T., Kikegawa, T.
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Journal Title
Am.Mineral. 90
Pages: 457-462
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Iron-water reaction at high pressure and temperature, and hydrogen transport into the core2005
Author(s)
Ohtani, E., Hirao, N., Kondo, T., Ito, M., Kikegawa, T.
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Journal Title
Phys.Chem.Mineral. 78, 2
Pages: 77-82
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Phase transitions of (Mg, Fe)O at megabar pressures2004
Author(s)
Kondo, T., Ohtani, E., Hirao, N., Yagi, T., Kikegawa, T.
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Journal Title
Phys.Earth Planet.Inter. 143-144
Pages: 201-213
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Compression of iron hydride to 80 GPa and hydrogen in the Earth's inner core2004
Author(s)
Hirao, N., Kondo, T., Ohtani, E., Takemura, K., Kikegawa, T.
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Journal Title
Geophys.Res.Lett. 31, L066169,doi:10.1029/2003 GL019380
Description
「研究成果報告書概要(欧文)」より
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