[ Top ] [ Japanese ]

Kori Formation Yamazaki, 1984

• Type locality: Atagobashi bridge - Koji - Nakayama tunnel, Okinoshima city, Oki county, Shimane prefecture
• Coherent formation
• Miocene (20 - 18 Ma; 21.3 - 14.6 Ma, FT; 21 - 18.0 Ma, K-Ar)
• Intruded by: Terayama Shoshonite, Hei Trachyte
• Correlation: Mita Formation

• Sedimentary facies: Fluvial, Lacustrine
• Sedimentary facies (Minor): Marine
• Sedimentary facies (Lower): Fluvial
• Sedimentary facies: River or Lake near the coast
• Climate (Top): Temperate - Warm temperate
• Climate (Upper): Warm temperate - Subtropical
• Climate (Middle): Warm temperate - Subtropical
• Climate (Lower): Temperate - Warm temperate
• Lithofacies (Top): Tuff, Interbedded mudstone and sandstone
• Lithofacies (Upper): Interbedded conglomerate, sandstone and mudstone, Andesite lava, Pyroclastic rocks, Hyaloclastite
• Lithofacies (Middle): Felsic pyroclastic rocks, Tuffaceous sandstone
• Lithofacies (Lower): Conglomerate, Basalt lava, Interbedded conglomerate, sandstone and mudstone
• Sedimentary structures (Minor, Marine): Slump structure
• Sedimentary structures (Lower): Upward-fining, Channel structure. Low angle cross-stratification, Imbricate structure
• Paleocurrent: to North-northeast

• Thickness: 200 - 2,600 m
• Upper limit: Unconformity (Kumi Formation, Omosu Formation, Mukogaoka Formation, Kama Basalt, Oku-kita Basalt, , Shimoganya Basalt, Ikeda Basalt, Saigo Basalt)
• Lower limit: Unconformity (Tokihariyama Formation, Oki Metamorphic Rocks)

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

• Distribution: Araki - Koji - Uzuki - Oku - Nakamuragawa river - Yamadagawa river - Shimonishi - Sai - Kojigawa river - Kitakata - Cape Nakumizaki - Nagaoda - Atagobashi bridge - Nakayama tunnel - Cape Noritabana - Nakamura port - Tokoyamagoe - Otsuku - Yui - Nagaoda, Okinoshima city, Oki county, Shimane pref.
• Fossils (Fishes, Freshwater): Scales, Bones, Pharyngeal teeth (family Cyprinidae)
• Fossils (Shellfishes, Freshwater): Bellamya kosasana, family Bithynidae, Cuneopsis sp., Lanceolaria sp., Lepidodesuma sp., Semisulcospira sp., Viviparus sp.
• Fossils (Daijima-type flora): Acer arasensis, Acer cf. chiharae, Acer ezoanum, Acer cf. imaii, Acer nordenskioldi, Acer subpictum, Alangium aequalifolium, Alnus miojaponica, Alnus protohirsta, Alnus protomaximowiczii, Alnus sp., Betula protojaponica, Betula uzenensis., Carex sp., Carpinus ishikiensis, Carpinus subcordata, Carpinus subyedoensis, Castanea miocrenata, Castanea ungeri, Celtis miobungiana, Cinnamomum miocenum, Cinnamomum cf. oguniense, Comptonia naumanni, Cornus sp., Equisetum sp., Fagus antipofi, Fothergilla sp., Fraxinus? sp., Gleditsea sp., Glyptostrobus europaeus, Ilex sp., Liquidambar miosinica, Liriodendron honshuensis, Machilus sp., Metasequoia occidentalis, Ostrya subvirgiana, Ostrya uttoensis, Parrotia sp., Picea kaneharai, Picea magna, Pinus sp., Populus nipponica, Pterocarya asymmetrosa, Quercus miovariabilis, Quercus nathorsti, Sasa sp., Sequoia sp., Sequoiadendroron primerium, Smilax sp., Thelypteris sp., Tilia sekiensis, Tsuga aburaensis, Ulmus carpinoides, Ulmus longifolia, Ulmus miopumila, Ulmus protojaponica, Zelkova ungeri

• Yamauchi et al. (2009) Geology of the Saigo District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 118p. (in Japanese with English abstract 3p.)