result 506 件
Author | Deguchi, Seigo| |
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Published Date | 1993 |
Publication Title | 岡山医学会雑誌 |
Volume | volume105 |
Issue | issue5-6 |
Content Type | Journal Article |
Author | Deguchi, Seigo| |
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Published Date | 1993 |
Publication Title | 岡山医学会雑誌 |
Volume | volume105 |
Issue | issue5-6 |
Content Type | Journal Article |
Author | Matsuoka, Hiroaki| |
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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| |
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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| |
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Published Date | 1994 |
Publication Title | 岡山医学会雑誌 |
Volume | volume106 |
Issue | issue5-6 |
Content Type | Journal Article |
Author | Tsuchida, Shohei| |
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Published Date | 1993 |
Publication Title | 岡山医学会雑誌 |
Volume | volume105 |
Issue | issue5-6 |
Content Type | Journal Article |
Author | Araki, Kazuhiro| |
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Published Date | 1993 |
Publication Title | 岡山医学会雑誌 |
Volume | volume105 |
Issue | issue5-6 |
Content Type | Journal Article |
Author | Mizuo, Kouzou| |
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Published Date | 1994 |
Publication Title | 岡山医学会雑誌 |
Volume | volume106 |
Issue | issue5-6 |
Content Type | Journal Article |
Author | Nishizawa, Masato| |
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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| |
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Published Date | 1993 |
Publication Title | 岡山医学会雑誌 |
Volume | volume105 |
Issue | issue5-6 |
Content Type | Journal Article |
Author | Shibayama, Takuo| |
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Published Date | 1993 |
Publication Title | 岡山医学会雑誌 |
Volume | volume105 |
Issue | issue3-4 |
Content Type | Journal Article |
Author | Namba, Kunihiro| |
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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| |
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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| |
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Published Date | 1994 |
Publication Title | 岡山医学会雑誌 |
Volume | volume106 |
Issue | issue3-4 |
Content Type | Journal Article |
Author | Sugiyama, Akira| |
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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| |
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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| |
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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 |
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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| |
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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 |
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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 |