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Hedate Formation Naruse, 1951

• Type locality: Okaseda, Chikura town, Minamiboso city, Chiba prefecture
• Coherent formation
• Landward slope basin of trench
• late Miocene - early Pliocene (5.6 - 3.75 Ma)
• Contemporaneous heterotopic facies (Lower): Nishizaki Formation
• Correlation: Kagamigaura Formation Kiyosumi Formation, Anno Formation

• Sedimentary facies: Marine
• Lithofacies (Upper): Siltstone-dominant interbedded sandstone and siltstone
• Lithofacies (Lower): Tuffaceous sandstone-dominant interbedded sandstone and siltstone
• Lithofacies (Lower, Minor): Scoria
• Sedimentary structures (Upper): Slump structures

• Thickness: 350 m or thicker
• Upper limit: Unconformity (Mera Formation)

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

• Distribution: Okaseda - Hedate - Chikura fishing port - Minamiasai, Chikura town, Minamiboso city, Chiba pref.
• Fossils: Foraminifera, Radiolarians
• Fossils (Calcareous nannofossils): Reticulofenestra pseudoumbilicus

• Utagawa et al. (2017) Jour. Geol. Soc. Japan, vol.123, no.11, pp.969-976 DOI
• Kawakami and Shishikura (2006) Geology of the Tateyama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 82p. (in Japanese with English abstract 5p.)