[ Top ] [ Japanese ]

Yasuda Formation (Sado, 1933) Kashiwazaki Plain Research Group, 1966

Invalid synonym: MI Terrace Deposit, Iwano Formation

• Type locality: Yokoyama, Kashiwazaki city, Niigata prefecture
• Coherent formation
• Middle terrace deposit
• Alluvial fan and river deposit of Ukawa river and Sabaishi river
• late Pleistocene (0.11 Ma, TL), Shimosueyoshi stage?
• Correlation: Maibara Terrace

• Sedimentary facies: Fluvial
• Sedimentary facies (Lower): Brackish
• Sedimentary facies: Lagoon, Alluvial fan, River
• Sedimentary facies (Lower): Coastal
• Climate (Upper): Cool
• Climate (Lower): Warm
• Lithofacies (Upper): Silt, Sands
• Lithofacies (Upper, Minor): Gravels
• Lithofacies (Lower): Silt, Clay, Sands

• Thickness: ca. 30 m
• Upper limit: Conformity (Banjin Sand), Unconformity (M II Terrace Deposit)
• Lower limit: Unconformity (Otusbo Formation, Haizume Formation, Oomigawa Formation, Suganuma Formation, Hachioji Formation)

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

• Distribution: Yokoyama - Kujiranami - Noge, Kashiwazaki city, Niigata pref.
• Fossils: Palaeoloxodon naumanni, Insects (Carabidae, Donaciinae), Shellfishes, Pollen
• Fossils (Lower, Shellfishes): Anadara sp., Cipangopaludina sp., Corbicula cf. japonica
• Fossils (Lower, Plants): Aesculus turbinata, Alnus japonica, Brasenia peltata, Euryale, akashiensis, Fagus crenata, Juglans sieboldiana, Scirpus sp., Styrax japonicum, Trapa macropoda

• Kobayashi et al. (1995) Geology of the Kashiwazaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 102p. (in Japanese with English abstract 4p.)
• Kobayashi et al. (1989) Geology of the Okanomachi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 112p. (in Japanese with English abstract 5p.)