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Yurihara Debris Deposits

Invalid synonym: Yurihara Debris Avalanche Deposit, Shirayukigawa Pyroclastic Flow Deposit

• Stratovolcano
• Coherent formation
• middle Pleistocene (40,480, 32,680 yBP, ¹⁴C)
• Older than Higher I Terrace Deposit.

• Lithofacies (Blocks): Andesite lava, Sandstone, Siltstone
• Lithofacies (Minor): Welded tuff

• Thickness: 30 - 80 m
• Upper limit: Unconformity (Kisakata Debris Avalanche Deposit, Okuyama Debris Avalanche Deposits)
• Lower limit: Unconformity (Sasaoka Formation, Nishime Formation, Torigoegawa Lava), Unknown (Iigamori Lava)

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

• Distribution: Yurihara, Yurihonjo city, Akita pref.; Uguisu river - Akagawa river, Chokai town, Yurihonjo city, Akita pref.; Hikaho hills, Naso river - Torigoe river, Nikaho city, Akita 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.)
• Ozawa et al. (1988) Geology of the Yashima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 87p. (in Japanese with English abstract 5p.)