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Tokushima Formation

Penetration resistance value (N value) is less than 50

• Coherent formation
• Pleistocene - Holocene
• Correlation: Takamatsu Formation, Ayagawa Formation, Urado Formation, Matsuyama Formation

• Sedimentary facies: Marine
• Lithofacies (Upper): Sand, Sandy gravels
• Lithofacies (Upper, Minor): Mud
• Lithofacies (Middle): Clay, Silt, Sands
• Lithofacies (Lower): Silt, Sands
• Lithofacies (Bottom): Sandy gravels
• Lithofacies (Bottom, Minor): Mud

• Thickness (Overall): 35 - 65 m
• Thickness (Upper): 13 - 24 m
• Thickness (Middle): 25 m or thinner
• Thickness (Lower): 11 - 20 m
• Thickness (Bottom): ca. 2 m or thinner
• Lower limit: Conformity (Kitajima Formation)
• Lower limit: Penetration resistance value (N value) = 50

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

• Distribution: Tokushima plain, Tokushima pref.
• Fossils: Shellfishes, Plants
• Tephra (Middle): K-Ah

• Kawamura and Nishiyama (2019) Jour. Geol. Soc. Japan, vol.125, no.1, pp.87-105 DOI