四国高知市付近の黒瀬川構造帯に産する208-240 m.y.の放射性年代を示すヒスイ輝石-藍閃石片岩

  • 丸山 茂徳
    Department of Earth Sciences, Faculty of Science, Nagoya University Department of Earth Science, Faculty of Education, Toyama University
  • 植田 良夫
    Institute of Mineralogy, Petrology and Economic Geology, Tohoku University
  • 坂野 昇平
    Department of Earth Sciences, Faculty of Science, Kanazawa University

書誌事項

タイトル別名
  • 208-240 M.Y. OLD JADEITE-GLAUCOPHANE SCHISTS IN THE KUPOSEGAWA TECTONIC ZONE NEAR KOCHI CITY, SHIKOKU

抄録

A new member of the Kurosegawa tectonic zone was found in the serpentinite near Kochi city. They are high P and low T schists derived from basalt and chert.<br> Three metamorphic events can be deciphered in the high-pressure schists, based upon the texture and mineral paragenesis: first, low P metamorphism at intermediate- to highgrade, second, high P and low T metamorphism of the jadeite-glaucophane facies and the thrid, retrograde crystallization of the second stage high P schists within the stability field of lawsonite+pumpellyite+glaucophane. Further, the formation of analcime replacing jadeite took place. The second and third metamorphism can be distinguished on pyroxene mineralogy that jadeite+quartz was stable in the second, but albite+quartz+aegirinejadeite in the third stage of metamorphism.<br> Not all of the high P and low T schists had suffered low P metamorphism before they were metamorphosed by the high P one. Some basaltic rocks directly changed to high P and low T schists.<br> Two muscovites in the schists give K-Ar ages of 208-240 m.y., and a relic igneous biotite, being partly replaced by chlorite, gives 225 m.y. of K-Ar age. These values are different not only from those of the Sanbagawa schists, but also from the other members of the Kurosegawa zone.

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詳細情報 詳細情報について

  • CRID
    1390001206217147648
  • NII論文ID
    130003728389
  • DOI
    10.2465/ganko1941.73.300
  • ISSN
    18830765
    00214825
    http://id.crossref.org/issn/03610128
  • データソース種別
    • JaLC
    • Crossref
    • CiNii Articles
  • 抄録ライセンスフラグ
    使用不可

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