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Shiogama Formation (Hanzawa et al., 1953) Ishii et al., 1982

Invalid synonym: Shiogama Pyroclastic Rock

• Type locality: Sakae town, Shiogama city - Goraku, Rifu city, Miyagi county, Miyagi prefecture
• Volcanic rocks
• early Miocene (22.3 Ma, K-Ar; 28.3 Ma, FT)
• Correlation: Oido Formation

• Sedimentary facies: Terrestrial
• Lithofacies: Augite hypersthene andesite tuff breccia, Volcanic breccia
• Lithofacies (Minor): Lapilli tuff, Pumice tuff, Tuffaceous sandstone
• Lithofacies (Bottom): Talus breccia

• Thickness: ca. 150 - 250 m
• Thickness (Basal): 10 - 20 m
• Upper limit: Bottom of volcanic conglomerate-bearing horizon
• Upper limit: Transitional (Sauramachi Formation), Unconformity (Hataya Formation, Tomegaya Formation, Kameoka Formation, Tatsunokuchi Formation), Abut unconformity (Irisugaya Formation)
• Lower limit: Unconformity (Rifu Formation)

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

• Distribution: Shiogama shrine - Shimizusawa - Sakae town - Lake Kasenuma, Shiogama city, Miyagi pref.; Miyamae - Taruta - Goraku, Rifu city, Miyagi county, Miyagi pref.
• Fossils (Basal sandstone breccia): Nipponitrigonia sp.

• Kitamura et al. (1986) Geology of the Sendai District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 134p. (in Japanese with English abstract 9p.)
• Kitamura et al. (1983) Geology of the Yoshioka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 50p. (in Japanese with English abstract 5p.)
• Ishii et al. (1983) Geology of the Shiogama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 112p. (in Japanese with English abstract 6p.)