[ Top ] [ Japanese ]

Imajuku Formation (Fukuda and Ishiwada, 1964) Majima, 1989

Invalid synonym: Imajuku Sandstone Member (Ohashi Formation, Tokigawa Group), Akanuma Formation

• Type locality: Akanuma, Hatoyama city, Saitama prefecture
• Coherent formation
• late Miocene

• Sedimentary facies: Marine, Shallower than Hatoyama Formation?
• Lithofacies (Upper): Tuffaceous fine-grained sandstone
• Lithofacies (Main): Massive medium-grained sandstone

• Thickness: 300 m +
• Lower limit: Conformity (Hatoyama Formation)
• Lower limit: Top of the siltstone bed (around 11.2 Ma)

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

• Distribution: Ohashi - Akanuma - Mameto - Juro, Hatoyama city, Saitama pref.
• Fossils: Bivalves, Crabs, Fishes (Scales), Plants (Lignite)

• Takahashi and Yanagisawa (2004) Jour. Geol. Soc. Japan, vol.122, no.12, pp.625-635.
• Kurihara et al. (2003) Jour. Geol. Soc. Japan, vol.109, no.4, pp.215-233.
• Koike et al. (1985) Jour. Geol. Soc. Japan, vol.91, no.10, pp.665-677.