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
Title Alternative
Chemical and Rb-Sr isotopic features of the shock-melted chondrite Yamato-793533
FullText URL
Author
Katayama, Hiroko
Nakamura, Noboru
Abstract
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.
Keywords
LL-chondrite
Shock-melting
Sr isotope
Publication Title
Okayama University Earth Science Report
Published Date
1999-09-20
Volume
volume6
Issue
issue1
Publisher
岡山大学理学部地球科学教室
Publisher Alternative
Department of Earth Sciences Faculty of Science, Okayama University
Start Page
29
End Page
38
ISSN
1340-7414
NCID
AN10506284
Content Type
Departmental Bulletin Paper
OAI-PMH Set
岡山大学
language
日本語
Copyright Holders
岡山大学地球科学研究報告編集委員会
File Version
publisher
NAID
Eprints Journal Name
esr