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Umeda Formation

• Coherent formation
• Holocene (ca. 8 ka - Present)
• Upper: Holocene (ca. 2,000 yBP - Present)
• Middle: Holocene (6,760 - ca. 3,000 yBP, ¹⁴C)
• Lower: Holocene (9,120 yBP, ¹⁴C)

• Sedimentary facies: Marine
• Sedimentary facies: Inner bay
• Sedimentary facies: Delta
• Sedimentary facies (Upper): Delta plain
• Sedimentary facies (Lower): Delta front
• Lithofacies (Top): Gravel-bearing sands
• Lithofacies (Upper): Silt, Sands
• Lithofacies (Middle): Clay
• Lithofacies (Lower): Silty clay
• Sedimentary structures (Lower): Parallel stratification

• Thickness: ca. 20 m
• Thickness (Upper): 4 m
• Thickness (Middle): 12.5 m
• Thickness (Lower): 3.5 m

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

• Distribution: Nankoohashi bridge, Nanko, Osaka city, Osaka pref.; Nakajimaohashi bridge - Tatsumi bridge, Kanzakigawa river, Osaka city, Osaka pref.
• Fossils (Shellfishes): Cipangopaludina sp., Corbicula japonica, Corbicula leana, Crassostrea gigas, Fulvia mutica, Meretrix lusolia, Ruditapes philippinarum, Trapezium (Neotrapezium) liratum

• Huzita and Maeda (1985) Geology of the Osaka-Seinambu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 103p. (in Japanese with English abstract 5p.)
• Huzita and Kasama (1982) Geology of the Osaka-Seihokubu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 112p. (in Japanese with English abstract 8p.)