[ Top ] [ Japanese ]

Torinosu Group

Synonym: Torinosu type Limestone, Torinosu Limestone

Name of a specific type of limestone facies, rather than a strata name. Black Cretaceous limestones with a odor of petroleum.

Included in Kurosegawa Belt, Southern Chichibu Belt, Southern Shimanto Belt.

• Type locality: Torinosu, Otsu, Sakawa city, Kochi prefecture
• Coherent formation
• Late Jurassic - Early Cretaceous
• Ehime pref., Kochi pref.: Late Jurassic, Kimmeridgian - Tithonian
• Correlation: Limestones in Kawanori Unit, Limestones in Hikawa Unit, Limestones in Happyakudani Unit, Limestones in Ichinosawa Unit, Limestones in Kumotoriyama Unit, Limestones in Happyakudani Unit, Limestones in Fukazawa Unit, Limestones in Yura Unit, Limestones in Ikenoue Formation, Imaidani Group

• Sedimentary facies: Marine
• Depth of water: Shallow, Continental shelf
• Lithofacies (Main): Limestone (including quartz grains)
• Lithofacies (Minor): Sandstone, Mudstone

• Upper limit: Fault
• Lower limit: Fault, Partial unconformity (Naradani Formation)

• Included in: Ebirase Formation

• Distribution: Iwaizumi (Iwate) - Soma (Fukushima) - Kanto - Yura (Wakayama) - Nomura (Ehime) - Azamui (Oita) - Yatsushiro (Kumamoto)
• Distribution (Wakayama): Kamiya - Mizukoshi pass, Yura city, Wakayama pref.
• Distribution (Kochi): Torinosu - Naradani valley, Sakawa city, Kochi pref.
• Distribution (Ehime): Oriai, Shirokawa village, Seiyo city, Ehime pref.; Sakuraga pass, Nomura city, Ehime pref.
• Distribution (Oita): Azamui, Oita pref.
• Distribution (Kumamoto): Shiraki - Yashikino, Ashikita city, Kumamoto pref.; Hashirimizu valley - Sakamoto, Yatsushiro city, Kumamoto pref.
• Fossils: Echinoids (Needles), Crinoids, Stromatoporoids, Hydrozoans
• Fossils (Ammonoids): Hybonoticeras cf. hybonotum, Hybonoticeras cf. mundulum, Hybonoticeras sp., Anavirgatites sp.
• Fossils (Hexacorallia): Aplosmilia? sp., Dimorpharaea tosaensis, Heliocoenia costulato, Isastraea sp., Pseudocoenia slovenia, Stylina higoensis, Stylina sugiyamai, Thamnasteria abukumaensis, Thamnasteria huzimotoi, Thecosmilia spp.
• Fossils (Rudists): Epidicera speciosum, Monopleura sp.
• Fossils (Hydrozoans): Spongiomorpha asiatica
• Fossils (Foraminifera): Nautiloculina broennimanni, Freixialina planispiralis, Charentia cuvillieri, Melathrokerion spirialis, Pseudocyclammina lituus
• Fossils (Sponges): Chaetetopsis crinita
• Fossils (Stromatopods): Parastromatopora japonica

• Murata and Takahashi (2017) Jour. Geol. Soc. Japan, vol.123, no.8, pp.585-597 DOI
• Onoue and Nishizono (2014) Jour. Geol. Soc. Japan, vol.120, Supplement, pp.1-17 DOI
• Kobayashi and Wernli (2013) Jour. Geol. Soc. Japan, vol.119, no.1, pp.25-38 DOI
• Maeda et al. (2012) Jour. Geol. Soc. Japan, vol.118, no.11, pp.741-747 DOI
• Yao (2012) Jour. Geol. Soc. Japan, vol.118, Supplement, pp.90-106 DOI
• Sano et al. (2007) Jour. Geol. Soc. Japan, vol.113, no.9, pp.500-503 DOI
• Sakai (1987) Geology of the Itsukaichi District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 75p. (in Japanese with English abstract 5p.)