[ Top ] [ Japanese ]

Uchiura Group

• Coherent formation
• middle Miocene
• Intruded by: Andesite dikes, Rhyolite, Quartz diorite

• Lithofacies (Upper): Andesite lava, Tuff, Tuff breccia
• Lithofacies (Middle): Mudstone
• Lithofacies (Middle, Minor): Sandstone
• Lithofacies (Lower): Andesite tuff breccia, Tuffaceous sandstone
• Lithofacies (Lower, Minor): Tuff, Lava
• Lithofacies (Basal): Conglomerate
• Sedimentary structures (Upper): Parallel stratification

• Thickness: ca. 250 - 700 m or thicker
• Thickness (Upper): ca. 200 m
• Thickness (Middle): ca. 100 - 270 m
• Thickness (Lower): ca. 15 - 40 m
• Thickness (Basal): ca. 0 - 60 m
• Upper limit: Unconformity (Oyama Andesite, Aobasan Andesite)
• Lower limit: Unconformity (Yakuno Complex, Oura Formation, Maizuru Group, Nabae Group, Rhyolite)

• Distribution: Uchiura - Konoura - Uwase - Hibiki - Kamakura - Ogurui - Otomi - Nabae - Nashima islands - Hirubatake - Deai - Takaya - Kowada, Takahama city, Oi county, Fukui pref.; Sugiyama - Noborio - Tochio - Tai - Naryu - Keshima island - Mizugaura - Matsuo, Maizuru city, Kyoto pref.
• Fossils (Shellfishes): Anadara kakehataensis, Cardium sp., Corbicula sp., Crassatellites sp., Crenella? sp., Cyclina takeyamai, Dentalium sp., Flabellum sp., Joanisiella takeyamai, Lima (Acesta) sp., Limopsis? sp., Lucina sp., Mactra (Oxyperas) cf. bernardi, Nassarius simizui, Natica sp., Ostrea gravitesta, Paphia sp., Phaxus sp., Polynices sp., Protorotella sp., Ralliolum peckhami, Siphonalia sp., Solen sp., Tellina sp., Vicarya yokoyamai

• Igi et al. (1961) Maizuru, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 49p. (in Japanese with English abstract 9p.)
• Hirokawa et al. (1958) Obama, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 31p. (in Japanese with English abstract 8p.)
• Hirokawa and Kuroda (1958) Tangoyura, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 23p. (in Japanese with English abstract 9p.)
• Hirokawa and Kuroda (1957) Nokogirizaki, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 22p. (in Japanese with English abstract 9p.)