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Hirokoba Lava (Kosaka et al., 2005) Mukai et al., 2009

• Type locality: 1,700 above sea level of Daimon creek, Matsumoto city, Nagano prefecture
• Volcanic rocks
• Pleistocene (1.56 Ma, K-Ar)

• Lithofacies: Hornblende two pyroxene andesite lava (a flow unit)

• Eruptive volume: 1.31 km³
• Thickness (Average): ca. 150 m
• Upper limit: Unconformity (Datekawarasawa Sandstone Member, Upper Ogahana Lava)
• Lower limit: Unconformity (Karasawa Granodiorite, Tobiratoge Volcaniclastics)
• Lower limit: Abut (Karasawa Granodiorite, Karasawagawa Volcanics)

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

• Distribution: 1,600 - 1,800 m above sea level of southern Utsukushigahara plateau, Nagano pref.
• Distribution: Daimon creek, Matsumoto city, Nagano pref.; Nonoiri river, Nagawa city, Chiisagata county, Nagano pref.

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