[ Top ] [ Japanese ]

Shimotamatagawa Formation Nakano and Tsuchiya, 1992

• Coherent formation
• Pleistocene (0.55 Ma, K-Ar)
• Simultaneous with Stage I of Chokai volcano

• Sedimentary facies: Terrestrial
• Lithofacies: Interbedded silt, sands and lapilli tuff
• Lithofacies (Minor): Tuff breccia, Basalt lava

• Thickness: 30 m or thicker
• Upper limit: Unconformity (Lower Akakuzurezawa Lava, Akakuzurezawamigimata Lava, Upper Akakuzurezawa Lava)

• Distribution: Shimotamata river - Akakuzure? creek, Chokai town, Yurihonjo city, Akita pref.

• Nakano and Tsuchiya (1992) Geology of the Chokaisan and Fukura District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 138p. (in Japanese with English abstract 7p.)