[ Top ] [ Japanese ]

Akahageyama Formation Chihara et al., 1979

• Type locality: Mount Akahageyama, Itoigawa city, Niigata prefecture
• Coherent formation
• Early - Late Cretaceous (94.2 Ma, FT)
• Correlation: Uchiyama Formation, Shiritakayama Formation

• Sedimentary facies: Terrestrial
• Lithofacies (Upper): Felsic tuff, Mafic tuff
• Lithofacies (Middle): Sandstone, Conglomerate
• Lithofacies (Middle, Minor): Mafic lapilli tuff, Tuff
• Lithofacies (Lower): Breccia, Conglomerate, Sandstone
• Sedimentary structures (Upper): Graded bedding

• Thickness: ca. 200 - 400 m
• Upper limit: Unconformity (Ipponmatsuyama Formation)
• Lower limit: Unconformity (Kotaki Formation)

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

• Distribution: Mount Akahageyama - Mount Anamiyama - Tsuchikurazawa creek - Mount Ipponmatsuyama - Shiritakazawa creek - Fudo fall, Mushikawa river, Itoigawa city, Niigata pref.
• Fossils (Plants): Xenoxylon sp.

• Takeuchi et al. (2015) Jour. Geol. Soc. Japan, vol.121, no.7, pp.193-216, DOI
• Nagamori et al. (2010) Geology of the Kotaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 130p. (in Japanese with English abstract 4p.)
• Takeuchi et al. (2010) Jour. Geol. Soc. Japan, vol.116, Supplement, pp.123-142 DOI