このエントリーをはてなブックマークに追加
ID 13907
JaLCDOI
Sort Key
4
タイトル(別表記)
Chemical and Rb-Sr isotopic features of the shock-melted chondrite Yamato-793533
フルテキストURL
著者
岡野 修 岡山大学大学院自然科学研究科
片山 博子 岡山大学理学部地球科学科
中村 昇 神戸大学理学部地球惑星科学科
抄録
The Sr isotopic compositions and Rb and Sr abundances, as well as major element abundances in olivine, pyroxenes and glass, were determined for a chip and 21 fractions separated from a shock-melted chondrite Yamato-793533, a dark-colored, porous stone with glassy texture. Two lithologies were recognized for the 1.5g specimen studied (Yamato-793533, 67) ; L (Main portion) and L to LL (Dark portion) chondritic in terms of chemical compositions of olivine and pyroxenes. The chemical compositions of glass are relatively homogeneous (SiO2=67-77%) compared to those of other ordinary chondrites, suggesting a moderate cooling rate after shock-melting. The data points for fractions do not foem any isochron in a 87Rb/86Sr vs. 87Sr/86Sr diagram. However, it is noted that six out of nine points for the dark portion plot around a 1.2 Ga line, while most of points for the main portion plot around a 4.55 Ga chondrite isochron. The observed difference could be responsible for difference in melting degrees between the two portions. Similar Rb-Sr features have been found among shock-melted Yamato-79 LL-chondrites which are considered to be paired stones experienced the same shock-melting event at 1.2 Ga. Consequently, the Rb-Sr systematics as well as petrologic features strongly suggest that Yamato-793533 is a member of a series of the shock-melted Yamato-79 LL-chondrites.
キーワード
LL-chondrite
Shock-melting
Sr isotope
出版物タイトル
Okayama University Earth Science Report
発行日
1999-09-20
6巻
1号
出版者
岡山大学理学部地球科学教室
出版者(別表記)
Department of Earth Sciences Faculty of Science, Okayama University
開始ページ
29
終了ページ
38
ISSN
1340-7414
NCID
AN10506284
資料タイプ
紀要論文
OAI-PMH Set
岡山大学
言語
Japanese
著作権者
岡山大学地球科学研究報告編集委員会
論文のバージョン
publisher
NAID
Eprints Journal Name
esr