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Tobiratoge Volcaniclastics (Tanaka and Hirabayashi, 1963) Mukai et al., 2009

Invalid synonym: Tobiratoge Formation, Tobiratoge Tuff Breccia

• Type locality: 1,600 m above sea level of Tobira pass, Matsumoto city - Nagawa city, Nagano pref.
• Volcanic rocks
• Pleistocene

• Sedimentary facies: Sector collapse deposit, Debris flow deposit
• Sedimentary facies: Block-and-ash flow (2 flow uniits)
• Sedimentary facies (Upper unit, Bottom): Pyroclastic surge
• Lithofacies: Dacite tuff breccia, Volcanic breccia
• Sedimentary structures (Upper unit): Reversed graded bedding

• Eruptive volume: 3.50 km³ or more
• Thickness (Yateikura creek): ca. 250 m
• Thickness (Nonoiri river): ca. 50 m
• Upper limit: Conformity (Lower Mitsumineyama Lava), Unconformity (Hirokoba Lava)
• Lower limit: Unconformity (Kotakiyama Group, Sanjiro Volcaniclastics)

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

• Distribution: 1,500 - 1,600 m above sea level of Sanjiro region, Matsumoto city, Nagano pref.; 1,450 - 1,700 m above sea level of Yateikura creek, Nagawa city, Chiisagata county, Nagano pref.; 1,500 - 1,700 m above sea level of west flank of Mount Mitsumine, Nagawa city, Chiisagata county, Nagano pref.

• Mukai et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.8, pp.400-422 DOI