Item type |
紀要論文(ELS) / Departmental Bulletin Paper(1) |
公開日 |
1984-12-01 |
タイトル |
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言語 |
en |
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タイトル |
A preliminary study of Rb-Sr systematics and trace element abundances on impact-melted LL-chondrites from Antarctica |
言語 |
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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 |
ページ属性 |
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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) |
Okano, Osamu
Misawa, Keiji
Nakamura, Noboru
Honma, Hiroji
Goto, Hiroya
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著者所属(英) |
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en |
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Department of Science of Material Differentation, Graduate School of Science and Technology, Kobe University/Department of Earth Sciences, Faculty of Science, Kobe University/Department of Science of Material Differentation, Graduate School of Science and Technology, Kobe University/Institute for Thermal Spring Research, Okayama University/Laboratory of Geosciences,College of Liberal Arts, Kobe University |
抄録(英) |
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内容記述タイプ |
Other |
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内容記述 |
Rb-Sr systematics, REE, Ba, Sr, Rb, K, Ca and Mg abundances were analyzed in 1) whole-rock samples from 8 Antarctic LL-chondrites including 4 impact-melted rocks and 2 non-Antarctic LL chondrites, and 2) 8 mineral separates from one of the impact-melted meteorites, Y-790964. In a ^<87>(Rb)-^<87>(Sr) evolution diagram, analyses from the severely shocked meteorites deviate from the 4.5 b. y.-evolution line although those of normal LL-chondrites are plotted on or close to the line, suggesting a late thermal evolution of these impact-melted meteorites. Analyses of mineral separates and a whole-rock from Y-790964 yield a Rb-Sr internal isochron age of 1197±54 (2σ) m. y. and an initial ^<87>(Sr)/^<87>(Sr) ratio of 0.73160±0.00028 (2σ). This age is the youngest known among impact-related materials in brecciated meteorites. In addition, the impact-melted meteorites have somewhat higher and fractionated REE, Sr, Rb and K abundances compared with normal LL chondrites. The 1.2 b. y. age is interpreted as a time of melting induced by intense impacts on the LL-chondrite parent body, accompanied by REE, Rb/Sr and K fractionations. Therefore, we suggest that strong impact and regolith processes on the LL-chondrite parent body never ceased until at least 1.2 b. y. ago. |
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 35,
p. 285-297,
発行日 1984-12
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