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Tokachimitsumata Pyroclastic Flow Deposit Ishii et al., 2008

Abbr.: Tkm-pfl

Invalid synonym: Muka Pyroclastic Flow Deposit (Tokachimitsumata basin), Muka Welded Tuff, Meto Pyroclastic Flow Deposit (Oribe-Osarushinai hills), Meto Tuff Bed, Kuttari Pyroclastic Flow Deposit (upstreams of Tokachi river), Kuttari Welded Tuff, Rubeshibe Pyroclastic Flow Deposit (Rubeshibe)

Abbr. (Invalid): Mk pfl, Mt pfl, Kt pfl, HR-4

• Tephra
• Pleistocene (ca. 1 Ma, K-Ar)
• Tokachimitsumata basin: Pleistocene (1.9 Ma, FT)
• Oribe-Osarushinai hills: Pleistocene (1.2 Ma, K-Ar; 0.99 Ma, FT)
• upstreams of Tokachi river: Pleistocene (0.96, 0.75 Ma, K-Ar)

• Sedimentary facies: Terrestrial
• Lithofacies: Rhyolitic
• Lithofacies: Welded tuff
• Lithofacies (Lower): Pyroclastic surge deposit
• Lithofacies (HR-4): Glassy crystalline ash
• Sedimentary structures (HR-4, Upper): Parallel stratification
• Sedimentary structures (HR-4, Lower): Upward-coarsening

• Source: Tokachimitsumata caldera
• Eruptive volume: ca. 10 km³
• Thickness (Tokachimitsumata basin): 100 - 200 m
• Thickness (Oribe-Osarushinai hills): a few m or thicker
• Thickness (upstreams of Tokachi river, Unit I): 100 m or thinner
• Thickness (upstreams of Tokachi river, Unit II): 100 m or thinner
• Thickness (Rubeshibe): 10 m or thicker
• Thickness (HR-4): 170 - 180 cm
• Host: Uppermost Ikeda Group
• Upper limit (Tokachimitsumata basin): Unconformity? (Gunkanyama Lava)
• Upper limit (Oribe-Osarushinai hills): Unconformity (Kamishikaribetsu Pyroclastic Flow Deposit)
• Upper limit (upstreams of Tokachi river): Unconformity (Shibusan Formation)
• Upper limit (HR-4): Unconformity (Ak9)
• Lower limit: Conformity (Tokachimitsumata Pyroclastic Fall Deposit)
• Lower limit (HR-4): Unconformity (Ak10)

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

• Distribution: Upper stream of Tokachi river - Tokachi plain - Kitami - Oketo, Hokkaido
• Distribution: Tokachimitsumata basin, Kamishihoro city, Kato county, Hokkaido; Oribe, Kamishihoro city - Osarushinai hills, Otofuke city, Kato county, Hokkaido; Uppre stream of Tokachi river, Hokkaido; Rubeshibe town, Kitami city, Hokkaido
• Distribution (HR-4): Kuchoro river, Hokkaido

• Hasegawa et al. (2008) Jour. Geol. Soc. Japan, vol.114, no.7, pp.366-381 DOI
• Ishii et al. (2008) Jour. Geol. Soc. Japan, vol.114, no.7, pp.348-365 DOI
• Hasegawa and Nakagawa (2007) Jour. Geol. Soc. Japan, vol.113, no.2, pp.53-72 DOI