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Tobu volcano group

Invalid synonym: Tobu volcano

• Volcanic rocks
• Composite stratovolcano
• middle Pleistocene (0.75 - 0.65 Ma)
• Correlation: Kuragoehoara Lava

• Lithofacies (Takane area, Upper): Hypersthene augite andesite lava
• Lithofacies (Takane area, Middle): Augite olivine basalt lava
• Lithofacies (Takane area, Lower): Andeiste pyroclastic rocks, Pyroclastic flow deposit
• Lithofacies (Otaki area): Hornblende andesite lava, Volcanic breccia, Tuff breccia
• Structures (Takane area, Upper): Platy joint
• Structures (Otaki area): Platy joint

• Source (Takane area): east of Mount Mamakodake
• Source (Otaki area): southeast of Mount Kengamine
• Thickness (Takane area): 20 m or thicker
• Thickness (Otaki area): 3 - 100 m or thicker
• Upper limit: Unconformity (Mikasayama volcano, Suzugasawa Lava, Nunokawa Lava)
• Lower limit: Unconformity (Makuiwagawa Lava, Mino Belt)

------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown

• Distribution (Takane area): Tsumetagawa river - Onoshiman fall, Kiso city, Kiso county, Nagano pref.; Nigorigogawa river, Takane town, Takayama city, Gifu pref.
• Distribution (Otaki area): Suzugasawa creek - Kiyotaki fall - Shintaki fall, Otaki city, Kiso county, Nagano pref.; Yukawa river - Kuragoekogen, Kiso city, Kiso county, Nagano pref.

• Takeuchi et al. (1998) Geology of the Kiso-Fukushima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 94p. (in Japanese with English abstract 4p.)
• Yamada and Kobayashi (1988) Geology of the Ontakesan District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 136p. (in Japanese with English abstract 9p.)