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Kawashiri Tuff Member Kitamura, 1959
- Type locality: Tsuchihata mine, Nishiwaga city, Iwate prefecture (Submerged)
- Volcanic rocks
- Half-graben associated with rifting of the back-arc basin (Japan sea)
- middle Miocene (15.4 - 13.6 Ma, 14 - 8.5 Ma, FT; 14 Ma, U-Pb)
- Sedimentary facies: Marine
- Sedimentary facies (Upper): Neptunian eruption (Large scale submarine explosion eruption)
- Sedimentary facies (Lower): Submarine lava dome (500 - 1,000 m diameter, 250 m height), Small scale submarine eruption
- Sedimentary facies: Submarine pyroclastic flow, Submarine surge, Talus cone
- Depth of water: 1,000 m or deeper (Middle bathyal, Giant pumices)
- Lithofacies (Upper): Reworked hyaloclastite
- Lithofacies (Upper): Pumice tuff, Rhyolite lava, Perlite, Lapilli tuff, Tuff breccia
- Lithofacies (Upper, Minor): Kuroko deposits, Hydrothermal vein deposits
- Lithofacies (Lower): Pumice tuff
------ Conformity, ~~~~~~ Unconformity, ~~~--- Local unconformity, '''/,, Interfingered, :::::: Fault, /--/-- Thrust, +__+__ Ground surface, ?--?-- Unknown
- Distribution: Tsuchihata mine - Washinosu river - Fukasawa - Koonigase river - Yukawa, Nishiwaga city, Iwate pref.
- Fossils: Bivalves (Patinopecten cf. kimurai), Sponges (Aphrocallistes sp.)
- Fossils (Foraminifera): Gyroidina orbicularis, Melonis pompilioides, Martinottiella communis, Spirosigmoilinella compressa, Globorotalia scitula praescitula, Globorotalia menardii praemenardii, Globobulimina perverse
- Hosoi et al. (2018) Jour. Geol. Soc. Japan, vol.124, no.10, pp.819-835 DOI
- Hosoi and Amano (2013) Jour. Geol. Soc. Japan, vol.119, no.9, pp.630-646 DOI
- Hosoi and Amano (2012) Jour. Geol. Soc. Japan, vol.118, no.8, pp.493-498 DOI
- Ozawa et al. (1971) Geology of the Kawashiri District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 40p. (in Japanese with English abstract 5p.)