Akahira Group

Akahira Group Takahashi, 2008

Invalid synonym: Chichibubonchi Group

Invalid synonym (Lower): Hikokubo Group

Type locality: Akahira river, Motogo, Yoshida, Chichibu city - Nagura, Ogano city, Chichibu county, Saitama prefecture
Coherent formation
Half graben-fill deposit
middle Miocene

Sedimentary facies: Marine

Thickness: 2,500 - 5,500 m
Lower limit: Unconformity (Ryokami Unit)

Akahira Group
[ Upper ]
?--?--?--?--?-
Chichibumachi Formation
--------------
Oganomachi Formation
--------------
Nenokami Formation
--------------
Tomita Formation
--------------
Shirasu Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Akahira river, Motogo, Yoshida, Chichibu city - Nagura, Ogano city, Chichibu county, Saitama pref.

Matsui et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.6, pp.261-266, DOI
Hara et al. (2010) Geology of the Mitsumine District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 110p. (in Japanese with English abstract 4p.)
Makimoto and Takeuchi (1992) Geology of the Yorii District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 136p. (in Japanese with English abstract 6p.)