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Zushi Formation (Watanabe, 1925) Minashi et al., 1979

Invalid synonym: Zushi Mudstone Formation

• Type locality: Yamanone, Zushi city, Kanagawa prefecture
• Coherent formation
• late Miocene (6.3 - 5.0 Ma, FT, K-Ar)
• Correlation: Kiyosumi Formation, upper Amatsu Formation
• Correlation (Upper): Hatsuse Formation
• Correlation (Lower): Misaki Formation

• Sedimentary facies: Marine
• Sedimentary facies: Forearc basin deposit
• Depth of water: upper - middle Bathyal (Foraminifear)
• Depth of water: 500 - 2,000 m (Foraminifear)
• Lithofacies: Mudstone
• Lithofacies (Minor): Sandstone, Tuff

• Thickness: ca. 1,000 - 1,500 m
• Upper limit: Transitional (Ikego Formation), Conformity, partly Unconformity (Takatoriyama Volcaniclastics Member), Fault (Jimmuji Volcaniclastics and Mudstone Member)
• Lower limit: Tagoegawa Unconformity (Hayama Group)

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

• Distribution: Yamanone, Zushi city, Kanagawa pref.; Kuruwa - Cape Chojagasaki, Hayama city, Miura county, Kanagawa pref.; Mount Ogusuyama - Cape Senda, Kurihama, Yokosuka city, Kanagawa pref.; Kamakura city, Kanagawa pref.
• Fossils: Sponges (Makiyama chitanii), Foraminifera
• Fossils: Zushi fauna
• Tephra: Ok, Bg, Hk, Nt

• Takahashi et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.8, pp.375-395, DOI
• Eto et al. (1998) Geology of the Yokosuka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 128p. (in Japanese with English abstract 3p.)