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Tanabu Formation (Kuwano, 1956) Tsushima and Takizawa, 1977

• Type locality: Shishibashi, Gamanosawa, Higashidori city, Shimokita county, Aomori prefecture
• Coherent formation
• Pleistocene

• Sedimentary facies (Upper): Shallow marine
• Sedimentary facies (Lower): Marine, Brackish - Freshwater
• Sedimentary facies (Lower): Inner bay
• Lithofacies (Upper): Sands
• Lithofacies (Upper, Minor): Silt, Gravels
• Lithofacies (Lower): Silt
• Lithofacies (Lower, Minor): Pumice bed, Interbedded sands and silt
• Sedimentary structures (Upper): Cross-stratification

• Thickness: 1 - 120 m
• Thickness (Upper): ca. 50 m
• Thickness (Lower): 15 m or thicker
• Upper limit: Unconformity (Terrace deposits)
• Lower limit: Unconformity (Sunagomata Formation, Shiriya Group)

• Distribution: Gamanosawa - Noushi - Iwaya - Iriguchi - Inasaki - Mena - Taya, Higashidori city, Shimokita county, Aomori pref.; Saibana, Tanabu, Mutsu city, Aomori pref.
• Fossils (Shellfishes): Ostrea gigas, Anadara cf. broughtoni, Macoma cf. incongrua, Macoma cf. praetexta, Cristaria plicata spatiosa, Raeta pulchella, Sphaerium sp., Theora lubrica
• Fossils (Plants): Juniperus sp., Potamogeton pectinatus, Ruppia maritima, Alnus japonica, Corylus heterophylla, Vitis cf. coignetiane, Styrax japonica, Thujopsis hondai, Cryptomeria japonica, Picea jezoensis var. hondoensis, Fagus crenata
• Fossils (Trace fossils): Pipe rocks
• Deposits: Iron sands

• Tsushima and Takizawa (1977) Geology of the Shiriyazaki District, Quadrangle Series, 1:50,000, Geological Survey of Japan, 32p. (in Japanese with English abstract 4p.)
• Imai (1961) Chikagawa, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 45p. (in Japanese with English abstract 4p.)