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Sanbosan Unit (Suzuki, 1931) Matsuoka et al., 1998

Invalid synonym: Sanbosan Group, Hisaidani Group, Sambosan Unit, Samposan accretionary complex

• Type locality: Mount Sanbo, Kochi prefecture
• Accretionary complex
• Deposition (Limestone): middle Carboniferous, Permian, Middle - Late Triassic Norian - Rhaetian (Foraminifera, Conodonts)
• Deposition (Chert): Permian, Middle - Late Triassic, Late Jurassic (Radiolarians)
• Deposition (Mudstone): Triassic - Early Cretaceous, Barremian (Radiolarians)
• Accretion: Late Jurassic - Early Cretaceous
• Correlation: Gozenyama Unit, Complex III, Wasabidani Complex, Tawarazu Formation (western Shikoku), Furuyabu Unit I?, Konose Unit, Yukagi Unit, Unit V, Omae Unit, Motobu Unit

• Sedimentary facies: Marine
• Sedimentary facies (Limestone, Triassic): Shallow marine, Panthalassa ocean
• Sedimentary facies (Limestone, Triassic): Biological reef
• Lithofacies: Mélange facies
• Matrix: Mudstone
• Matrix (Minor): Interbedded sandstone and mudstone
• Exotic blocks (Slabs): Limestone (Micrite, Biomicrite), Chert, Sandstone, Mudstone, Basalt lava, Volcaniclastic rocks

• Thickness (Limestone): 250 - 500 m
• Distribution (Width): 200 m - ca. 1.5 km
• Upper limit: Thrust fault (Togano Unit)
• Lower limit: Thrust fault (Shimanto Belt)

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

• Distribution: Kanto - Akaishi mountains - Shima peninsula - Kii peninsula, southern Shikoku - southern Kyushu - Okinawa
• Distribution: Nakagawa river - Mononobegawa river - Hisaidanigawa river - Oriudanigawa river - Tochidanigawa river, Naka city, Naka county, Tokushima pref.; Inaba cave, Funado, Tsuno city, Takaoka county, Kochi pref.; Kutajima island, Hioki city, Kagoshima pref.
• Fossils: Radiolarians
• Fossils (Limestone): Bivalves (Megalodon sp.), Crinoids, Sponges, Corals, Calcareous algae, Foraminifera, Conodonts
• Fossils (Limestone, Foraminifera): Agathammina austroalpina, Alpinophragminum perforatum, Galeanella panticae, Hoyenella inconstans, Trochammina sp., Reophax sp., Ophthalmidium spp., Palaeolituonella meridionalis, Nubecularia? sp., Microtubus communis, Cheilosporites sp.

• Miyazaki (2024) Geology of the Iyo-Nagahama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 155p. (in Japanese with English abstract 5p.)
• Takahashi et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.1, pp.1-22, DOI
• Hara et al. (2014) Geology of the Kitagawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 72p. (in Japanese with English abstract 4p.)
• Onoue et al. (2009) Jour. Geol. Soc. Japan, vol.115, no.6, pp.292-295 DOI
• Yoshida and Onoue (2008) Jour. Geol. Soc. Japan, vol.114, no.5, pp.246-249 DOI
• Kiminami and Toda (2007) Jour. Geol. Soc. Japan, vol.113, no.4, pp.158-167 DOI