Relict Clinopyroxenes in the Mikabu Greenstones, Oshika and Kosetokyo Districts, Nagano Prefecture, Central Japan

Watanabe, Teruo; Kawachi, Yosuke; Yuasa, Makoto

北海道大学理学部紀要, 1978, 18(4), 509-520

Permalink : https://hdl.handle.net/2115/36670

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URI	https://hdl.handle.net/2115/36670
タイトル	Relict Clinopyroxenes in the Mikabu Greenstones, Oshika and Kosetokyo Districts, Nagano Prefecture, Central Japan
著者	Watanabe, Teruo ; Kawachi, Yosuke ; Yuasa, Makoto
著者名 Watanabe, Teruo
著者名 Kawachi, Yosuke
著者名 Yuasa, Makoto
言語	英語
発行日	1978-09
出版者	北海道大学
出版者	Hokkaido University
収録物名	北海道大学理学部紀要
収録物名	Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy
巻(号)	18(4)
ページ	509-520
抄録	Magma types and spilitization process of the metamorphosed greenstones (Mikabu greenstones) in the Oshika and Kosetokyo districts were examined on the basis of the chemical composition of rocks and relict clinopyroxenes. The alkali contents of the rocks are plotted in both alkaline and tholeiite basalt fields. However, most greenstones with high alkali contents have less TiO2 and P2O5 than typical alkali basalts. One of the rocks carries the clinopyroxene with high Si and low Ti contents as in tholeiite basalts. These features may be interpreted as due to spilitization. It is suggested that most of the original rocks of the Mikabu greenstones of these districts, especially of Kosetokyo district, show an oceanic tholeiite affinity, though some an alkali basaltic affinity.
資源タイプ	紀要論文
出版タイプ	Version of Record
PISSN	0018-3474