[ Top ] [ Japanese ]

Ichibu Formation Naemura and Shimada, 1984

• Type locality: Seaside Hotel, Ichibu, Nishinoshima city, Oki county, Shimane prefecture
• Coherent formation
• middle Miocene
• Correlation: Tsuma Formation (Kamaya Member)

• Sedimentary facies: Marine
• Lithofacies (Upper): Sandstone turbidite
• Lithofacies (Upper, Minor): Siltstone, Mudstone
• Lithofacies (Lower): Sandstone
• Lithofacies (Minor): Felsic tuff, Conglomerate, Tuffaceous sandstone
• Sedimentary structures (Upper): Graded bedding
• Sedimentary structures (Lower): Cross stratification

• Upper limit: Unconformity (Takuhiyama Pyroclastic Cone)
• Lower limit: Unconformity (Otsu Formation, Mita Formation)

• Distribution: Ichibu, Nishinoshima city, Oki county, Shimane pref.
• Fossils: Foraminifera (Cribroelphidium imanishii), Trace fossils (Ohiomorpha isp.)
• Fossils (Shellfishes): Acila sp., Anadara tazawensis, Buccinum cf. mitsuganoensis, Callista sp., Chlamys cosibensis, Clinocardium shinjiense, Conchocele bisecta, Crassostrea gigas, Cultellus izumoensis, Glycymeris sp., Dosinia sp., Kaneharaia kaneharai fujinaensis, Lavicardium shiobaraense, Lucinoma acutilieatum, Limatula subauriculeta blanda, Macoma praetexts, Macoma optiva, Margarites eos, Mizuhopecten cf. nakatombetsuensis, Mya grewinghi, Panope nomurae, Panope japonica, Patinopecten egregius, Patinopecten tokunagai, Portlandia sp., Raeta sp., Saccella sp., Saxidomus cf. purpuratus, Schizaster sp., Solen sp., Soletellina sp., Tellina sp., Thyasira tokunagai, Turritella caishuensis, Yoldia sp.
• Fossils (Plants): Acer sp., Alnus? sp., Cyclobalanopsis sp., Lithocarpus sp., Pterocarya sp.

• Chiba et al. (2000) Geology of the Urago District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 74p. (in Japanese with English abstract 3p.)