(K-Ar ages of muscovite from greenstone in the Ino formation and schist blocks associated with the Kurosegawa tectonic zone near Kochi City, central Shikoku.)

Translated title of the contribution: Japanese with English abstract

Y. Ueda, T. Nakajima, K. Matsuoka, S. Maruyama

Research output: Chapter in Book/Report/Conference proceedingChapter

7 Citations (Scopus)

Abstract

The Kurosegawa tectonic zone is a serpentinite melange zone in which various kinds of tectonic blocks occur. Muscovites coexisting with high-P minerals gave ages of 352-394 m.y. They indicate that so-called semischists were neither metamorphosed at the time of formation of the Kurosegawa tectonic zone, nor by the Sanbagawa metamorphism, but show a distinct metamorphic event older than Middle Carboniferous. This is the oldest radiometric age among glaucophane schists in Japan. Muscovites from the schist xenoliths of albite-epidote amphibolite facies grade were dated at 317 and 327 m.y. by the K/Ar method. Hornblende and barroisite are sometimes replaced by actinolite or riebeckite along their cleavages or irregular cracks. Muscovite is also deformed to show kink-band folding and is chloritized parallel to cleavage or along irregular cracks. Therefore, the values 317 and 327 m.y. may not show the time of albite-epidote amphibolite facies metamorphism, but are older than those of the Sanbagawa schists.-M.Ak.

Original languageJapanese
Title of host publicationJournal of the Japanese Association of Mineralogists, Petrologists & Economic Geologists
Pages230-233
Number of pages4
Volume75
Edition7
Publication statusPublished - 1980
Externally publishedYes

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ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Environmental Science(all)

Cite this

Ueda, Y., Nakajima, T., Matsuoka, K., & Maruyama, S. (1980). (K-Ar ages of muscovite from greenstone in the Ino formation and schist blocks associated with the Kurosegawa tectonic zone near Kochi City, central Shikoku.). In Journal of the Japanese Association of Mineralogists, Petrologists & Economic Geologists (7 ed., Vol. 75, pp. 230-233)