| Project/Area Number |
59065001
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| Research Category |
Grant-in-Aid for Specially Promoted Research
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| Allocation Type | Single-year Grants |
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| Research Institution | University of Tokyo |
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Principal Investigator |
OZIMA Minoru Facultv of Science, Universitv of Tokyo Professor, 理学部, 教授 (20011471)
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| Co-Investigator(Kenkyū-buntansha) |
KANEOKA Ichiro Earthquake Research Institute, Associate University of Tokyo Professor, 地震研究所, 助教授 (30011745)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥112,600,000 (Direct Cost: ¥112,600,000)
Fiscal Year 1986: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1985: ¥19,000,000 (Direct Cost: ¥19,000,000)
Fiscal Year 1984: ¥89,600,000 (Direct Cost: ¥89,600,000)
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| Keywords | Noble qases / Isotopic compositions / Mantle evolution / Origin of atmosphere / Diamonds / 希ガス |
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| Research Abstract |
We measured <^3He> / <^4He> ratio and Ne isotopic ratios in diamonds He isotopic ratios range from <10^(-7)> to <10^(-4)> , which is quite similar to our previous results. <^(20)Ne> / <^(22)Ne> ratios range from 11 to 13. Both the He and Ne isotopic ratios suggest strongly that the primordial He and Ne in the earth are identical with a solar type ones.
We measured more than 100 deep-sea sediments from the Pacific and Atlantic Oceans for <^3He> / <^4He> ratio. We observed very high <^3He> / <^4He> (- <10^(-4)> ), which is concluded due to the incorporation of extra-terrestrial materials, such as IDPs (inter planetary dust particles). The amount of the incorporated IDPs is estimated to be from 0.1 to 10 ppm. Detailed isotopic analyses on magnetic separates from deep-sea sediments show that He and Ne isotopic compositions are similar to solar flare components, i.e., <^3He> / <^4He> = (1.8 <-!+> 0.4) x <10^(-4)> and <^(20)Ne> / <^(22)Ne> = 11.6 <-!+> 0.6.
We compiled published terrestrial Xe isotopic data and discussed the mantle evolution, we conclude from the Xe isotopic data that there still remains primitive region(s) in the mantle which has been decoupled from the rest of the mantle since the formation of the earth.
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