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Shirasakayama Tuff Member (Hanzawa et al., 1953) Ishii et al., 1982

• Type locality: Mount Shirasaka, Matsushima city, Miyagi county, Miyagi prefecture
• Volcanic rocks
• Miocene

• Sedimentary facies: Submarine pyroclastic flow deposit
• Lithofacies: Pumice tuff
• Lithofacies (Minor): Tuff
• Lithofacies (Lower): Tuffaceous sandstone
• Lithofacies (Lower, Minor): Breccia
• Sedimentary structures: Slump structures, Bioturbation, Pipe rocks

• Thickness: ca. 50 - 130 m
• Thickness (Main part): ca. 15 - 95 m
• Thickness (Lower): ca. 1 - 40 m
• Lower limit: Bottom of breccia or tuffaceous sandstone beds
• Lower limit: Conformity (Upper Member, Nemari Tuffaceous Sandstone Member), Unconformity (Siltstone Member, Lower Pumice Tuff Member)

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

• Distribution: Mount Shirasaka - Sorimachi - Mount Anetori - Irizawa, Matsushima city, Miyagi county, Miyagi pref.; Niizeki, Osato city, Kurokawa county, Miyagi pref.
• Fossils: Shell fragments

• Ishii et al. (1982) Geology of the Matsushima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 121p. (in Japanese with English abstract 9p.)