Title Transcription | オキ ドウゴ ノ デイシツ ミグマタイト ニ フクマレル リュウタイ ホウユウブツ ノ ケンキュウ
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Title Alternative (English) | Fluid Inclusion Study of Pelitic Migmatite from Oki-Dogo Island
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File | |
language |
jpn
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Author |
Kashima, Takashi
Tsunogae, Toshiaki
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Description | This study examined composition of fluid inclusions in leucocratic and melanocratic parts of pelitic migmatites from Oki-Dogo to understand fluid activity throughout P-T history of high-T/low-P metamorphic terrane. Calculated fluid density and isochores range from 0.73 to 0.84g/<cm>^^^3 and from 450 to 540℃ at 3kbar, respectively, for H_2O, and from 0.7l to 0.87g/<cm>^^^3 and from 540 to 860℃ for CO_2 inclusions. The temperature range for the
CO_2 inclusions is almost consistent with previously estimated peak and retrograde conditions ; 750~820℃ at l.5~4kbar for peak and 580~630℃ at 2.9~3.9kbar for retrograde conditions. The range for the H_2O inclusions is, however, significantly lower than the retrograde condition. Our results therefore suggest that CO_2-bearing fluid was dominant during peak to retrograde metamorphism, while H_2O-rich fluid infiltrated at the last stage of metamorphism. Graphite is the most probabie source of CO_2 because the CO_2 inclusion becomes dominant with increasing modal abmdance of graphite in migmatites. Origin of H_2O is not clearly understood, but probably associated with an uplifting of metamorphic terrane providing H_2O-bearing hydrothermal fluid from middle crust. The later H_2O infiltration brought about hydration of garnet and biotite to chlorite and muscovite, which marks the end of thermal events of Oki metamorphic rocks. |
Journal Title |
Memoirs of the Faculty of Education, Shimane University. Natural science
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Volume | 31
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Start Page | 35
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End Page | 43
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ISSN | 05869943
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Published Date | 1997-12-01
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NCID | AN00107941
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Publisher | 島根大学教育学部
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Publisher Aalternative | The Faculty of Education Shimane University
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NII Type |
Departmental Bulletin Paper
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OAI-PMH Set |
Faculty of Education
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他の一覧 |