[ Top ] [ Japanese ]

Oirasegawa Pyroclastic Rock (Hayakawa, 1985) Takarada and Muraoka, 2004

Invalid synonym: Oirase scoria cone

• Type locality: Tamasudare fall, Oirase river, Towada city, Aomori prefecture
• Underwater lava dome
• Volcanic rocks
• Pleistocene (1.0 - 0.8 Ma)
• Contemporaneous heterotopic facies: Nenokuchi Lacustrine Formation

• Sedimentary facies: Lacustrine
• Lithofacies: Olivine-bearing hypersthene augite basaltic andesite
• Lithofacies: Scoriaceous volcanic bomb, Volcanic lapilli
• Sedimentary structures: Reversed graded bedding

• Thickness: 20 m

• Distribution: Oirase river, Towada city, Aomori pref.

• Takarada and Muraoka (2004) Geology of the Hakkoda San District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 86p. (in Japanese with English abstract 4p.)