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Harimichi Pass

Harimichi, Sakurai city, Nara pref., Japan


Neutral metasomatic rocks of Illite-Chlorite zone

Sericitization zone and low temperature hydrothermal deposit formed by the middle Miocene (15 Ma) Muro Rhyolites along the fracture zone related to the Median Tectonic Line in the Late Cretaceous (76 Ma) Hatsuse Quartz Diorite. The Hatsuse Quartz Diorite was formed by the Late Cretaceous (100 Ma) low-pressure Ryoke metamorphism. The Median Techitonic Line is parallel to the trench, and the boundary between the high-pressure Sambagawa metamorphic rocks and the low-pressure Ryoke metamorphic rocks. The Muro Rhyolites is the top bed of the Soni Formation, and is considered as the pyroclastic flow from the Odai Caldera. Approximately 7 km apart from the Median Techtonic Line, 20 km from the Odai Caldera. Metamorphic age was determined by CHIME dating of monazite, volcanic rocks by fission track dating and K-Ar radiometric dating of biotite or hornblende.

Reported Minerals

  • Pyrite
  • Berthierite
  • Stibnite
  • Metacinnabar
  • Cinnabar
  • Marcasite
  • Arsenopyrite
  • Kermesite
  • Stibiconite
  • Gypsum
  • Sericite

Mineral Assemblages

  • Sericite - Pyrite
  • Quartz(Gangue) - Berthierite - Stibnite
  • Quartz(Gangue) - Cinnabar


Related Occurrences

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