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Nagusa-Kamicho, Ashikaga city, Tochigi pref., Japan


Hornblende-hornfels facies contact metamorphic rocks

Mudstone of Kurohone-Kiryu Complex of Ashio Belt, a member of Jurassic accretionary complex, has been subjected to hornblende-hornfels facies contact metamorphism by Cretaceous granodiorite of Ashikaga Body, and andalusite was formed in it. Approximately 100 m apart from the heat source, Ashikaga Body.


Outcrop of andalusite-hornfels formed by hornblende-hornfels facies metamorphism of mudstone, a matrix of Kurohone-Kiryu Complex. The black outcrop is composed of andalusite-bearing hornfels, and flat schistosity was recognized. Andalusite is too small to see in this photograph but they are clear pale pink and aligned along schistosity.

Reported Minerals

  • Andalusite
  • Pyrite

Mineral Assemblages

  • Hornfels - Andalusite - Pyrite
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