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Awashima island

Awashima island, Numazu city, Shizuoka pref., Japan


Andesite vesicules

Minerals observed in the fissures of andesite of the late Miocene - Pliocene (9.0 - 3.0 Ma) Shirahama Group. Andesite is calc-alkaline to tholeiite series. Ages of sediments were determined by microfossils and K-Ar radiometric dating.


Outcrop of andesite of Shirahama Group.. The translucent crystals in the fissures of the andesite are calcite. Also, some fissures includes white granular crystals of crystobalite. The white part at the bottom is lichenes growing on the surface of the outcrop.

Reported Minerals

  • Crystobalite
  • Calcite
  • Epistilbite
  • Pyroxene

Mineral Assemblages

  • Fissure - Calcite - Crystobalite
  • Fissure - Epistilbite
  • Host - Pyroxene


Related Occurrences

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