[ Top ] [ Japanese ]

Koganeyama Formation Sakai, 1958

• Type locality: Mount Kogane, Onizawa, Hirosaki city, Aomori prefecture
• Coherent formation
• Pleistocene

• Sedimentary facies: Lacustrine
• Sedimentary facies: Lake associated with older stratovolcano stage of Iwakisan volcano
• Lithofacies (Upper): Pumice tuff, Sandy tuff
• Lithofacies (Middle): Interbedded sands, gravels and clay
• Lithofacies (Lower): Siltstone, Clay
• Lithofacies (Lower, Minor): Lignite
• Lithofacies (Bottom): Andesitic lapilli tuff

• Thickness: 100 - 150 m or thicker
• Upper limit: Unconformity (Yamadano Formation, Volcanic products of Iwakisan volcano)
• Lower limit: Unconformity (Narusawa Formation, Higashimeya Formation)

• Distribution: Mount Kogane, Onizawa, Hirosaki city, Aomori pref.
• Fossils (Plants): Menyanthes trifoliata

• Ozawa and Hirayama (1970) Geology of the Goshogawara District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 25p. (in Japanese with English abstract 3p.)
• Ozawa (1962) Hirosaki, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 52p. (in Japanese with English abstract 5p.)