Item type |
紀要論文(ELS) / Departmental Bulletin Paper(1) |
公開日 |
2001-10-01 |
タイトル |
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タイトル |
Sm-Nd garnet ages of retrograde garnet bearing granulites from Tonagh Island in the Napier Complex, East Antarctica: A preliminary study |
言語 |
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言語 |
eng |
キーワード |
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言語 |
en |
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主題Scheme |
Other |
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主題 |
Napier Complex |
キーワード |
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言語 |
en |
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主題Scheme |
Other |
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主題 |
Sm-Nd garnet age |
キーワード |
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言語 |
en |
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主題Scheme |
Other |
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主題 |
Proterozoic |
キーワード |
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言語 |
en |
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主題Scheme |
Other |
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主題 |
retrograde metamorphism |
資源タイプ |
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資源タイプ識別子 |
http://purl.org/coar/resource_type/c_6501 |
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資源タイプ |
departmental bulletin paper |
ID登録 |
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ID登録 |
10.15094/00003086 |
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ID登録タイプ |
JaLC |
ページ属性 |
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内容記述タイプ |
Other |
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内容記述 |
P(論文) |
著者名(英) |
Owada, Masaaki
Osanai, Yasuhito
Tsunogae, Toshiaki
Hamamoto, Takuji
Kagami, Hiroo
Toyoshima, Tsuyoshi
Hokada, Tomokazu
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著者所属(英) |
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en |
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Department of Earth Sciences, Yamaguchi University/Department of Earth Sciences, Okayama University/Institute of Geoscience, the University of Tsukuba/Graduate School of Science and Technology, Niigata University/Graduate School of Science and Technology, Niigata University/Graduate School of Science and Technology, Niigata University/National Institute of Polar Research |
抄録(英) |
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内容記述タイプ |
Other |
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内容記述 |
Proterozoic Sm-Nd garnet ages were dated from a garnet-bearing quartzo-feldspathic gneiss (Grt-felsic gneiss) and an iron rich garnet-pyroxene gneiss (Fe-rich Grt-Py gneiss) in the northern part of Tonagh Island, the Napier Complex. The Grtfelsic gneiss occurs as a member of layered gneiss. The Fe-rich Grt-Py gneiss appears as a block in the felsic gneiss. Since the layered gneiss contains a critical mineral assemblage of ultrahigh-temperature (UHT) metamorphism such as sapphirine+quartz, the Grt-felsic and the Fe-rich Grt-Py gneisses have undergone UHT metamorphism whose age is believed to be Late Archaean. The inclination line connecting with garnet and whole rock in the Grt-felsic gneiss yields an age of 1897 Ma in the Sm-Nd system. The internal isochron using garnet, pyroxenes and whole rock for the Fe-rich Grt-Py gneiss gives an age of 1557±35 Ma. Both Sm-Nd internal isochron ages correspond to Early Proterozoic. Garnet-quartz symplectite and quartz occur between orthopyroxene and plagioclase in the Grt-felsic gneiss. This texture indicates the following reaction: orthopyroxene+plagioclase=garnet+quartz. The garnet in the Fe-rich Grt-Py gneiss occurs as interstitial mineral with small grained clinopyroxene and quartz. Taking reaction textures into account, the garnet forming reactions in the Grt-felsic and the Fe-rich Grt-Py gneisses would occur during retrograde events after UHT peak metamorphism. The ages of c. 1900 and c. 1550 Ma would therefore reflect tectonothermal events in the Napier Complex. |
雑誌書誌ID |
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収録物識別子タイプ |
NCID |
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収録物識別子 |
AA1130866X |
書誌情報 |
Polar geoscience
巻 14,
p. 75-87,
発行日 2001-10
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出版者 |
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出版者 |
National Institute of Polar Research |