2003 Fiscal Year Final Research Report Summary
Geochemical Study on the Oldest Halite Fossil in the Solar System
| Project/Area Number |
13440165
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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 |
地球化学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NAGAO Keisuke The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (40131619)
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| Co-Investigator(Kenkyū-buntansha) |
KAGI Hiroyuki The University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (70233666)
TAKIGAMI Yutaka Kanto Gakuen University, Professor, 法学部, 教授 (40206909)
KANEOKA Ichiro The University of Tokyo, Earthquake Research Institute, Professor, 地震研究所, 教授 (30011745)
MIURA Yayoi n. The University of Tokyo, Earthquake Research Institute, Research Assistant, 地震研究所, 助手 (90282730)
NAKAMURA Tomoki Kyushu University, Faculty of Science, Associate Professor, 大学院・理学研究院, 助教授 (20260721)
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| Project Period (FY) |
2001 – 2003
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| Keywords | noble gas isotopes / halite / halogens / neutron irradiation / I-Xe age / ^<40>Ar-^<39>Ar age / Zag meteorite / formation age |
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| Research Abstract |
Halogens and their crystals (halide) have been investigated in Zag and other halogen containing meteorites by detecting halogen-derived noble gas isotopes ^<80>Kr, ^<82>Kr and ^<128>Xe^<129>Xe from extinct nuclide was ^<129>I also measured in these meteorites. Halide crystals are dark phase portion of the Zag meteorite. Size of most crystals are estimated to be smaller than 0.1 mm, which would be surrounded by silicates insoluble in water. Halogens are also concentrated in small materials in Yamato-74191 (L3.6) meteorite. The halogen enrichments in these meteorite are likely resulted by liquid water with high concentrations of halogens presented on their parent planetesimals. Though origin of the waters is not clear, they might have been brought through bombardment by water containing objects such as carbonaceous chondrites or comets.
To study the event concerning the halogen enrichments, we constructed noble gas extraction and purification line for noble gas analysis of neutron irradiated meteorites. Modification of VG3600 noble gas mass spectrometer used for ^<40>Ar-^<39>Ar dating was carried out to improve sensitivity and stability of the mass spectrometer in the Radioisotope Center, University of Tokyo. Combining the noble gas line and the mss spectrometer, I-Xe dating of meteorites can be measurable for the first time in Japan. This method began to clarify the timing of halogen enrichment process in meteorites.
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[Publications] Honda, M., Caffee, M.W., Miura, Y.N., Nagai, H., Nagao, K., Nishiizumi, K.: "Cosmogenic nuclides in the Brenham Pallasite."Meteorit.Planet.Sci.. 37. 1711-1728 (2002)
Description
「研究成果報告書概要(欧文)」より
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