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Author Deguchi, Seigo|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue5-6
Content Type Journal Article
Author Deguchi, Seigo|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue5-6
Content Type Journal Article
Author Matsuoka, Hiroaki|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue5-6
Content Type Journal Article
Author Iwagaki, Hiromi| Fuchimoto, Sadanori| Hamada, Fumihiro| Shiiki, Shigeo| Yasui, Yoshimasa| Matsubara, Nagahide| Akazai, Yoshihiro| Watanabe, Tetsuya| Gouchi, Akira| Hizuta, Akio| Kamikawa, Yasuaki| Orita, Kunzo|
Published Date 1991-08
Publication Title 岡山医学会雑誌
Volume volume103
Issue issue7-8
Content Type Journal Article
Author Nakamura, Tohru|
Published Date 1994
Publication Title 岡山医学会雑誌
Volume volume106
Issue issue5-6
Content Type Journal Article
Author Tsuchida, Shohei|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue5-6
Content Type Journal Article
Author Araki, Kazuhiro|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue5-6
Content Type Journal Article
Author Mizuo, Kouzou|
Published Date 1994
Publication Title 岡山医学会雑誌
Volume volume106
Issue issue5-6
Content Type Journal Article
Author Nishizawa, Masato|
Published Date 1993-12-31
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue11-12
Content Type Journal Article
Author Higashi, Ryouhei|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue5-6
Content Type Journal Article
Author Shibayama, Takuo|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue3-4
Content Type Journal Article
Author Namba, Kunihiro|
Published Date 1993-02-27
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue1-2
Content Type Journal Article
Author Namba, Kunihiro|
Published Date 1993-02-27
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue1-2
Content Type Journal Article
Author Makino, Hirohumi| Nagake, Yoshio| Ogura, Toshio| Haramoto, Toshinori| Matsumoto, Mitsuhito| Haramatsu, Makoto| Mino, Yasuaki| Nishimura, Shigeaki| Taniai, Kazuhi| Kumagai, Isao| Komoto, Kiichi| Takehisa, Yoshiaki| Matsuura, Umeharu| Suga, Yoshihiko| Ota, Zensuke|
Published Date 1994
Publication Title 岡山医学会雑誌
Volume volume106
Issue issue3-4
Content Type Journal Article
Author Sugiyama, Akira|
Published Date 1993-02-27
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue1-2
Content Type Journal Article
Author Takeuchi, Makoto|
Published Date 1993-12-31
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue11-12
Content Type Journal Article
Author Kitamura, Tomoki|
Published Date 1993-10
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue9-10
Content Type Journal Article
JaLCDOI 10.18926/ESR/13949
Title Alternative Rb-Sr age of K-rich LL-chondrite Yamato-74442
FullText URL ESR_2_91.pdf
Author Nishiya, Nanayo| Okano, Osamu| Kagami, Hiroo| Nakamura, Noboru|
Abstract Yamato-74442, a brecciated LL-group chondrite, consists of fragments with igeous texture, chondrules, mineral fragments, and host. The fragments involve K-rich fragments as well as normal ones. Typically, both fragments consist mainly of euhedral porphyritic olivines and a few orthopyroxenes in a glassy grundmass. EPMA analyses for these fragments indicate that olivines and orthoptroxenes have a range of Fe/(Fe+Mg) ratio of 27.19~31.33 and 20.10~26.91 mol%, respectively. There is no significant difference in these rations between K-rich (Na2O/K2O<1) and normal framents. The K2O contents of groundmass for K-rich fragments range from 0.51 to 4.89 wt% and that of the normal fragments is 0.38~090 wt%. K2O contents of groundmass vary from fragment to fragment but are rather homegeneous in a single fragment. Rb-Sr isotopic determination on eighteen K-rich fragments (1.5 to 9.5mg in weight) gave an internal isochron age of 4.514±0.022 (2σ) Ga (λ87Rb=1.42×10-11y-1) and initial 87Sr/86Sr ratio of 0.7016±0.0024. This age is somewhat old compared with a whole rock isochron age of LL chondrites (4.493±0.18 Ga; Minster and Allegre, 1981). From a comoarison of the present result with others so far reported, it is inferred that the alkali differentiation as observed in Yamato-74442 probably occurred prior to or during a process of accumulation from LL chondrite parent material in the early solar nebula. 
Keywords LL-chondrite Rb-Sr age Sr isotope K-rich fragment
Publication Title Okayama University Earth Science Report
Published Date 1995-09-20
Volume volume2
Issue issue1
Start Page 91
End Page 102
ISSN 1340-7414
language Japanese
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310270
Author Shiiki, Shigeo| Nakagawa, Kazuhiro| Sasaki, Hiroshi| Yamashita, Yutaka| Yumura, Masahito| Kodani, Johji| Yunoki, Yasuhiro| Orita, Kunzo|
Published Date 1993-02-27
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue1-2
Content Type Journal Article
JaLCDOI 10.18926/ESR/13907
Title Alternative Chemical and Rb-Sr isotopic features of the shock-melted chondrite Yamato-793533
FullText URL ESR_6_29.pdf
Author Okano, Osamu| 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
Start Page 29
End Page 38
ISSN 1340-7414
language Japanese
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310391