高圧実験と地震波観測による統合的アプローチを用いた沈み込み帯下の構造と進化の解明
【研究キーワード】
mantle composition / high pressure / ultrasonic measurement / seismological model / triplication
【研究成果の概要】
P- and S-wave velocities (VP and VS) are the unique tool we have to explore the inaccessible deep Earth and planetary interiors via comparisons with the observed seismic velocities. In this FY we carried out additional VP and VS measurements of MORB composition as well as Martian peridotite in the framework of an international collaboration with the Institut de Mineralogie et Physique des Materiaux Condenses (IMPMC, France). We also conducted sound velocity measurements on partially molten Olivine + FeS samples, which were meant to test the feasibility of such measurements for the partial melting of hydrated MORB components in a pyrolitic mantle. All sound velocity measurements on the rock aggregates were carried out by in situ ultrasonic interferometry, X-ray radiography and diffraction techniques, at high P and T in the multianvil press at the beamline Bl04B1 located at the synchrotron facility SPring-8.
Analyses of the MORB, pyrolite and harzburgite data collected in the previous FY are now underway, and several papers are in preparation. Preliminary results from the partial melting experiments suggest the VS/VP primarily depends on the micro-texture of the silicate matrix that contains the melt rather the composition of the melt itself, although the latter might play a role in controlling the mobility of the melt in the silicate matrix. Our results suggest harzburgitic composition can explain high shear seismic velocities observed above the 660, while MORB and/or partial melt are necessary to explain the low velocities beneath the 660.
【研究代表者】
【研究分担者】 |
| 肥後 祐司 | 公益財団法人高輝度光科学研究センター | 回折・散乱推進室 | 主幹研究員 | (Kakenデータベース) |
| 河合 研志 | 東京大学 | 大学院理学系研究科(理学部) | 准教授 | (Kakenデータベース) |
| 佐藤 友彦 | 岡山理科大学 | 基盤教育センター | 准教授 | (Kakenデータベース) |
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【研究種目】基盤研究(B)
【研究期間】2019-04-01 - 2023-03-31
【配分額】17,810千円 (直接経費: 13,700千円、間接経費: 4,110千円)