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Shirasawatengu-SK100 Tephra (Niigata Plain Collaborative Research Group, 1970) Yasui et al., 1983

Abbr.: Srt-SK100

Synonym.: SK100, Iz, Gjd20

• Type locality: Shibanomata river, Oguni town, Nagaoka city, Niigata prefecture
• Tephra
• Pleistocene (1.78, 1.60 - 1.54 Ma, FT; ca. 1.6, 1.58 Ma, Calcareous nannofossils)
• Correlation: Sg1 (Yokohama, Kanagawa), Sh, Kd24, Ob4c (Choshi, Chiba), Km2 (Oga, Akita), Zushi 2

• Sedimentary facies: Submarine gravity flow deposit
• Lithofacies: Rhyolite vitreous volcanic ash
• Sedimentary structures: Parallel stratification, Trough cross-stratification
• Sedimentary structures (Minor): Convolute lamination

• Source: Shirasawatengu caldera, Nagano pref., Japan
• Thickness: 0.4 - 9 m
• Thickness (Upper): 7 - 10 cm
• Thickness (Lower): 20 - 25 cm
• Thickness (Unit IV): 70 cm
• Host: Haizume Formation, Nishiyama Formation, Uonuma Formation, Furuto FormationKakuma Formation, Minagawa Formation, , Kiwada Formation
• Upper limit: Conformity (Tr-TB Tephra)

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

• Distribution: Shibanomata river - Kunisawa river, Oguni town, Nagaoka city, Niigata pref.; Tanaka - Jorakuji, Izumozaki city, Santo county, Niigata pref.; Chofukuji, Kamo city, Niigata pref.; Furuto, Sanjo city, Niigata pref.; Kogurosu - Miyadaira, Kashiwazaki city, Niigata pref.; Tsubono, Takayanagi town, Kashiwazaki city, Niigata pref.; Murojima - Kojirakura - Tarusawa river - Miyanaka, Tokamachi city, Niigata pref.; Tsujimata river, Uonuma city, Niigata pref.; Tokimizu, Ojiya city, Niigata pref.; Boso peninsula, Chiba pref.

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