| Project/Area Number |
12573012
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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 | 海外学術 |
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| Research Field |
地球化学
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
HIROSE Kei Tokyo Inst of Tech, Assoc.Prof, 大学院・理工学研究科, 助教授 (50270921)
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| Co-Investigator(Kenkyū-buntansha) |
OZAWA Hiroaki Naruto University of Education, Research Associate, 学校教育学部, 助手 (60253241)
TAKAHASHI Eiichi Tokyo Inst of Tech, Prof., 大学院・理工学研究科, 教授 (40144779)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥16,000,000 (Direct Cost: ¥16,000,000)
Fiscal Year 2001: ¥8,000,000 (Direct Cost: ¥8,000,000)
Fiscal Year 2000: ¥8,000,000 (Direct Cost: ¥8,000,000)
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| Keywords | diamond / zircon / peridotite / pyroxeneite / high-pressure / テクストフェア / 初期地球 / 地球ダイナミクス / マントルカンラン岩 / エクロジャイト / 二次イオン質量分析計 |
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| Research Abstract |
In the first year, we made a field work at Ronda peridotite massif in southern Spain for four weeks. About five hundred rock samples were collected, and the occurrence of pyroxenites in peridotite was observed in details. In the following year, we visited diamond mines in South Africa and Botswana in order to collect mantle nodules. Botswana is famous for world best diamond mines, but the mines have long been closed to geologists. According to the efforts by Japanese embassy, we were fortunately permitted to collect rocks in all of three mines currently operated in this country.
We have done dating using zircon grains in such a diamond mine. Analyses were made by the group of Prof. Sano at Hiroshima University using SHRIPM. The U/Pb age of 77 Ma was obtained from the analyses of 12 grains. This age likely indicates the kimberite eruption age.
Microscope observations as well as microprobe analyses were made on peridotite samples from mines in Botswana. Results show that part of the samples were highly deformed, which are possibly asenosphere origin. Using petrological thermobarometer, we determined the mantle geotherm beneath continent.
We also made high-pressure experiments and determined the mineral chemistry in both peridotitic and basaltic compositions up to 27 GPa. These results could be a good reference to investigate the origins of nodules coming from the interior of the Earth.
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