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Horaisan Volcanic Rocks

• Stratovolcano
• Old edifice
• Volcanic rocks
• Pleistocene

• Lithofacies: Calc-alkaline
• Lithofacies: Olivine augite andesite, Hypersthene augite andesite
• Lithofacies: Tuff breccia, Lapilli tuff, Tuff, Tuffaceous sandstone
• Lithofacies (Minor): Lava

• Thickness (Overall): ca. 200 m
• Thickness (Lava): 3 - 5 m
• Upper limit: Unconformity (Lower Kanomatagawa Lava, Gakkogawa Lava, Odaino Pyroclastic Flow Deposit)
• Lower limit: Unconformity (Maruyama Formation)

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

• Distribution: Mount Horai - Yunodai - Kanomata river, Kusatsu river, Sakata city, Yamagata pref.

• Nakano and Tsuchiya (1992) Geology of the Chokaisan and Fukura District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 138p. (in Japanese with English abstract 7p.)