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Lower Member

Probably same as Ryozen Formation.

• Type locality: Onigasaku, Marumori city, Igu county, Miyagi prefecture
• Coherent formation
• early Miocene
• Interfingered: Tenmyosan Volcanic Rocks
• Contemporaneous heterotopic facies: Tsukinoki Formation
• Correlation: Lower Tenmyosan Volcanic Rocks, Shiote Formation

• Sedimentary facies: Lacustrine
• Lithofacies: Conglomerate, Sandstone, Tuffaceous sandy siltstone
• Lithofacies (Minor): Tuff
• Lithofacies (Basal): Breccia

• Thickness: 170 m
• Upper limit: Top of Kanazu Tuff
• Upper limit: Conformity (Kanazu Tuff, Upper Member)
• Lower limit: Abut unconformity (Karosan Formation, Wariyama Granite)

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

• Distribution: Onigasaku - Nakadaira - Aoba, Marumori city, Igu county, Miyagi pref.
• Fossils: Eostegodon pseudolatidens
• Tephra: Kanazu Tuff

• Fujita et al. (1988) Geology of the Kakuda District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 99p. (in Japanese with English abstract 9p.)