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Tsudaka Formation Suzuki et al., 2003

Invalid synonym: Asahigawa Formation (a local name at Kumenan city)

• Type locality: Tsudaka, Okayama city, Okayama prefecture
• Coherent formation
• late Eocene (29.4, 27.4 Ma, FT)

• Sedimentary facies: Fluvial
• Sedimentary facies: Valley-fill deposit, Channel-fill deposit
• Sedimentary facies (Minor): Talus
• Lithofacies (Upper): Conglomerate
• Lithofacies (Middle): Sandstone, Mudstone
• Lithofacies (Middle, Minor): Coal
• Lithofacies (Lower): Conglomerate
• Sedimentary structures: Trough cross-stratification

• Thickness: 160 m or thicker
• Width (Tsudaka): 500 - 4,500 m
• Width (Ashimori): 300 - 700 m
• Altitude (Tsudaka): -20 - 200 m
• Altitude (Ashimori): 10 - 300 m
• Upper limit: Unconformity (Tomiyoshi Formation)
• Lower limit: Unconformity (Nariwa Group)

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

• Distribution: Tsudaka - Karako - Minoji - Kakehata, Okayama city, Okayama pref.; Miyaji, Kumenan city, Kume county, Okayama pref.; Fukui - Ashimori, Soja city, Okayama pref.

• Suzuki et al. (2009) Jour. Geol. Soc. Japan, vol.115, Supplement, pp.139-151 DOI