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Momoyake Volcanic Rocks Nakano and Tsuchiya, 1992

It has been considered as a basal part of Chokai volcano

Invalid synonym: Horo Lava, Horo Agglomerate, Nunosawagawa Lava, Hanaremori Basaltic Breccia Agglomerate, Momoyake Breccia Tuffaceous Agglomerate, Momoyake Tuff Breccia

• Volcanic rocks
• late Miocene - early Pliocene (7.1 - 3.4 Ma, K-Ar)
• Intruded by: Andesite, Rhyolite

• Lithofacies (Main part): Olivine augite andesite, Augite andesite, Augite hypersthene andesite volcanic breccia, Lava
• Lithofacies (Main part, Minor): Tuff breccia, Lapilli tuff, Tuff, Mudstone
• Lithofacies (Lapilli tuff): Lapilli tuff, Tuff, Tuffaceous sandstone Sandstone, Siltstone
• Lithofacies (Lapilli tuff, Minor): Tuff breccia

• Source: Submarine volcano in a distance
• Thickness (Main part): 200 - 500 m or thicker
• Thickness (Lapilli tuff): 100 - 150 m
• Lower limit: Conformity, partly interfingered (Funakawa Formation)

• Distribution: Koyoshi river - Mount Hinoto, Yurihonjo city, Akita pref., Futatsuyama, Odate city, Akita pref.
• Fossils (Mudstone): Diatoms

• 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.)