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Hakkoda 2nd-stage Pyroclastic Flow Deposit Muraoka and Takakura, 1988

Abbr.: Hkd2

Invalid synonym: Oirase Dacite, Nosagake Formation, Hakkoda Welded Tuff, Nagatoro Tuff, Hasezawa Tuff, Tashirotai Welded Tuff

• Type locality: Iguri fall, Arakawa, Aomori city, Aomori prefecture
• Tephra
• Pleistocene (ca. 0.43 Ma; 0.4 Ma, K-Ar; 0.37 Ma, FT; 0.25 Ma, TL)

• Sedimentary facies: Terrestrial
• Lithofacies: Non - weakly - strongly welded tuff
• Lithofacies: Dacitic - Rhyolitic pyroclastic flow deposit
• Lithofacies (Size of plagioclase): 4 - 5 mm in maximum

• Eruptive volume: 8.5 km³
• Thickness: 6 - 150 m
• Source: Hakkoda caldera
• Host: Maedanome Formation, Rokumantai Formation
• Upper limit: Conformity (Rokumantai Formation), Unconformity (Koganedai Lava, Tsuta Debris Avalanche Deposit, Tamoyachidake Lava, Odake 1st-stage Lava, Aobunayama Pyroclastic Rocks and Lava, Towada-Hachinohe Pyroclastic Flow Deposit), Unknown (Kuroishi Fan Deposit)
• Lower limit: Conformity (Maedanome Formation), Conformity? (Hakkoda 1st-stage Pyroclastic Flow Deposit), Unconformity (Isodayama Formation, Aoni Tuff, Minami-Hakkoda 3rd-stage Lava and Pyroclastic Rocks, Tsutagawa Pyroclastic Deposit, Kuromori Lava, Okogawazawa Debris Flow Deposit, Horyokita Lava)

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

• Distribution: Iguri fall, Arakawa, Aomori city, Aomori pref.; Nyunai, Aomori city, Aomori pref.; Nyunai, Aomori city, Aomori pref.; Daishaka, Namioka, Aomori city, Aomori pref.; Kogano - Rokumantai, Kuroishi city, Aomori pref.; Uwano, Aomori city Aomori pref.; Sabaishi - Teshiromori, Owani city, Minamitsugaru county, Aomori pref.; Kengyodai-Makino - Sekihandai - Fuchisawa river - Domeki - Shikinai river - Odamichi - Kiyose, Towada city, Aomori pref.

• Nagamori et al. (2013) Geology of the Aomori-Seibu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 67p. (in Japanese with English abstract 4p.)
• Kudo (2005) Geology of the Towada District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 79p. (in Japanese with English abstract 3p.)
• 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.)