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Usuginu Formation (Noda, 1934) Takeuchi and Mikoshiba, 2002

Separated from Toyoma Formation by Takeuchi and Mikoshiba, 2002.

Invalid synonym: Yamazaki Conglomerate Member

• Type locality: Mount Takauto - Miyahata, Fujisawa town, Ichinoseki city, Iwate prefecture
• Coherent formation
• middle Permian
• Correlation: Takagami Conlomerate, Kanokura Formation

• Sedimentary facies: Marine
• Lithofacies: Usuginu Conglomerate, Sandstone, Mudstone
• Sedimentary structures: Graded bedding

• Thickness: ca. 1,000 m
• Upper limit: Top of the upper most Usuginu Conglomerate
• Upper limit: Conformity (Toyoma Formation)
• Lower limit: Conformity (Nishikori Formation)

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

• Distribution: Mount Takauto - Miyahata, Fujisawa town, Ichinoseki city, Iwate pref.; Satetsu river - Numata - Idozawa, Ichinoseki city, Iwate pref.
• Fossils: Fusulinids (Lepidolina multiseptata)
• Fossils (Limestone gravels, Fusulinids): Lepidolina sp., Parafusulina rodaiensis, Pseudofusulina popensis, Pseudofusulina toyomensis
• Fossils (Limestone gravels, Corals): Wentzelella sp., Yatsengia sp.
• Fossils (Sandstone gravels): Monodiexodina matsubaishi

• Ehiro and Morikiyo (2013) Jour. Geol. Soc. Japan, vol.119, Supplement, pp.47-67 DOI
• Takeuchi and Mikoshiba (2002) Geology of the Senmaya District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 76p. (in Japanese with English abstract 3p.)
• Hirokawa and Yoshida (1956) Ohazama, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 31p. (in Japanese with English abstract 9p.)