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Mikunisan Rhyolites

• Type locality: Mount Mikunisan - Kyogotoge pass, Niimi city, Okayama prefecture
• Volcanic rocks
• Pleistocene
• Intruded by: Granite porphyry, Biotite granite, Granodiorite, Diorite

• Lithofacies: Rhyolite welded tuff, Lava, Breccia, Tuff breccia, Lapilli tuff
• Lithofacies (Minor): Andesite - Dacite pyroclastic rocks
• Sedimentary structures: Graded bedding

• Thickness: ca. 100 - 530 m
• Distribution (Width): 10 km or longer
• Upper limit: Unconformity (Takao Andesites, Bihoku Group)
• Lower limit: Unconformity (Yuno Formation, Serpentinite)

• Distribution: Mount Mikunisan - Kyobodawa pass - Sasao - Mimuro - Aosasa - Mount Myokenyama - Mount Takanosuyama - Shingo - Takase-Umeda - Yanagihara - Yoshida - Shigo - Komodawa pass - Atetsu valley - Okugumi - Kumatani - Onigo - Mount Tenginyama - Bicchukojiro station - Komoto dam, Niimi city, Okayama pref.; Besshaku - Kashiraji - Yabutani - Ogoyadani, Tojo town - Shobara city, Hiroshima pref.

• Hattori (1978) Geology of the Kami-Iwami District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 65p. (in Japanese with English abstract 4p.)