| Project/Area Number |
26400514
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Petrology/Mineralogy/Economic geology
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| Research Institution | Kyoto University |
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Principal Investigator |
KOGISO Tetsu 京都大学, 人間・環境学研究科, 教授 (60359172)
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| Research Collaborator |
KONDO Nozomi
YOSHINO Takashi
MATSUKAGE Kyoko
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Project Status |
Completed (Fiscal Year 2016)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2016: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2015: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2014: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
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| Keywords | 岩石鉱物鉱床学 / 地球惑星内部構造 / 初期地球 / 地球化学 / 高圧実験 / マグマ / 岩石・鉱物・鉱床学 / 地球・惑星内部構造 |
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| Outline of Final Research Achievements |
The present Earth has a higher 142Nd/144Nd ratio than most chondrites. Thus, if the Earth is assumed to have formed from chondrite, a complement low-142Nd/144Nd reservoir (hidden reservoir) is needed. We estimated the age and conditions to form the hidden reservoir based on Sm-Nd partitioning and melting phase relations. Our estimate indicates that the hidden reservoir should have formed within ~30 Myr from the Earth formation and at 7 GPa, 1750°C. We then performed high pressure melting experiments on primitive peridotite to determine the major element composition of a melt that can be the hidden reservoir at this condition, and calculated its density. The results indicate that the melt is iron- and titanium-rich komatiite. The estimated density of the melt is lower than that of the primitive peridotite, suggesting that the melt would have ascended in the mantle to form crust in the Hadean and have been ejected from the Earth by the giant impact.
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