1999 Fiscal Year Final Research Report Summary
Study on the initial states of the solar system by measuring microdistribution of noble gases in meteorites
| Project/Area Number |
09304055
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
TAKAOKA Nobuo Kyushu University, Graduate School of Sciences, Professor, 大学院・理学研究科, 教授 (40028171)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Tomoki Kyushu University, Graduate School of Sciences, Research Associate, 大学院・理学研究科, 助手 (20260721)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Noble gas isotope / carbonaceous chondrite / Planetesimal / Cosmic dust / IDP / Dehydration / Impact metamorphism / Evolution of solar system |
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| Research Abstract |
In order to determine physico-chemical process and condition to affect the evolution of materials in the early solar system, noble-gas microdistribution was measured by a laser microprobe technique and was compared to the meteorite texture. Trapped gases in carbonaceous chondrites reside mainly in chondrule rims. Solar gas was found in comminuted parts but not in primary accreted rocks, indicating that the material density of the solar nebula was so high that the solar wind did not reach the formation region of chondrule rims. Gas-loss from Allende was determined by artificially applying impact-shocks of 30 to 70 GPa to it. At 70 GPa shock, part of rock melted and 70% of Q-Gas was lost, whereas HL-gas that was trapped in presolar diamond was retained without loss. Gas-loss-following dehydration of phyllosilicate minerals was studied as well to find physico-chemical conditions in the early solar nebula. Gas concentration in dehydrated carbonaceous chondrites is constrained by heating temperature and time as well as graphitization of organic carbon.
Cosmic dusts including IDP, Antarctic micrometeorites and magnetic deep-sea spherules were analyzed for noble-gas, trace element and mineral composition. Determinations of mineral compositions of IDP and micrometeorites and trace element abundance for magnetic spherules were carried out using high luminosity of synchrotron radiation.
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