Item type |
紀要論文(ELS) / Departmental Bulletin Paper(1) |
公開日 |
1979-03-01 |
タイトル |
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言語 |
en |
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タイトル |
40Ar-39Ar Age Studies of Four Yamato-74 Meteorites |
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言語 |
eng |
資源タイプ |
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資源タイプ識別子 |
http://purl.org/coar/resource_type/c_6501 |
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資源タイプ |
departmental bulletin paper |
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内容記述タイプ |
Other |
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内容記述 |
P(論文) |
著者名(英) |
Kaneoka, Ichiro
Ozima, Minoru
Yanagisawa, Masahisa
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著者所属(英) |
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en |
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Geophysical Institute, Faculty of Science, University of Tokyo |
著者所属(英) |
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en |
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Geophysical Institute, Faculty of Science, University of Tokyo |
著者所属(英) |
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en |
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Geophysical Institute, Faculty of Science, University of Tokyo |
抄録(英) |
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内容記述タイプ |
Other |
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内容記述 |
^<40>(Ar)-^<39>(Ar) ages have been obtained for four Yamato-74 meteorites (Yamato-74640,-74190,-74159 and -74097) from Antarctica. Yamato-74640 (H5-6) shows a plateau age of 4407±71 m.y. (1σ) at higher temperatures. This age probably corresponds to the time of formation or a very intense metamorphism for this meteorite. Yamato-74190 (L6) indicates a ^<40>(Ar)-^<89>(Ar) age spectrum with a low temperature plateau-like age of 357±32 m.y. The apparent ^<40>(Ar)-^<39>(Ar) age increases up to about 1300 m.y., but does not reach a high temperature plateau. The apparent young age would reflect the time of degassing due to the collisional process of the parent body, which has been observed in many L-chondrites. Yamato-74159,which is a eucritic polymict breccia, has a similar age spectrum to that of Pasamonte obtained by PODOSEK and HUNEKE (Geochim. Cosmochim. Acta, 37,667,1973), indicating a plateau age of 4075±49 m.y. at intermediate temperatures (850-1250℃). This age may reflect the time of the later degassing event such as the impact of meteoroids on the parent body of the eucrite. Yamato-74097 (Diogenite) seems to show a relatively young ^<40>(Ar)-^<39>(Ar) age of about 1100 m.y., though the uncertainty in the obtained age is larger for this diogenite than those for the other samples due to its low K-content. From both the value of the age and the age spectrum, this diogenite seems to have a different history from those of ordinary chondrites and achondrites known to date. |
雑誌書誌ID |
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収録物識別子タイプ |
NCID |
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収録物識別子 |
AA00733561 |
書誌情報 |
Memoirs of National Institute of Polar Research. Special issue
巻 12,
p. 186-206,
発行日 1979-03
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