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Shogunzawa Formation (Fukuda and Ishiwada, 1964) Kurihara et al., 2003 (Photo)

Invalid synonym: Shogunzawa Siltstone Member

• Type locality: Mae river, Shogunzawa, Ranzan city, Saitama prefecture
• Coherent formation
• middle Miocene
• Correlation: Tsuchishio Formation

• Sedimentary facies: Marine, Offshore, Muddy floor
• Lithofacies (Upper): Massive diatom-bearing siltstone
• Lithofacies (Main): Massive siltstone
• Lithofacies (Bottom): Sandy siltstone

• Thickness: 350 m -
• Upper limit: Conformity (Hatoyama Formation)
• Upper limit: Bottom of the first sandstone above the I-12 Tuff Bed (around 11.5 Ma)
• Lower limit: Conformity (Negishi Formation)
• Lower limit: Top of the I-3 Tuff Bed (around 12.7 Ma)

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

• Distribution: Most of Iwadono hills; Kuzubukuro - Iwadono, Higashimatsuyama city, Saitama pref.; Negishi, Ranzan city, Saitama pref.; Okuda - Fuefuki pass - Takemoto - Kumai, Hatoyama city, Saitama pref.
• Fossils, Shellfishes, Solitary corals, Brachiopods, Echinoids, Plants, Forams, Diatoms, Calcareous nannofossils, Radiolarians
• Tephra: I-3.5, (I-4), I-5, I-6, I-7, I-8, I-9, I-10, I-11 (Shogunzawa Tuff Bed), I-12 (Okuda Tuff Bed), I-13

• 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.