Azumaya Lavas

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Azumaya Lavas Ota and Katada, 1955

Volcanic rocks
Middle Pleistocene (0.66 - 0.57 Ma, K-Ar)

Lithofacies: Lava, Pyroclastic rocks
Lithofacies: Orthopyroxene andesite, Orthopyroxene-clinopyroxene andesite

Upper limit: Unconformity
Lower limit: Unconformity (Ibaraki Lavas, Yonago Lavas)

Initial volcanic edifice
[ Upper ]
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Daimyojinzawa Lava
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Azumaya Lavas
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Kamgawa Lavas
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Otani Lavas
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Ibaraki Lavas
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Koikeyama Lavas
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Yonago Lavas
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[ Lower ]

Azumaya volcano
[ Upper ]
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Urakurayama volcanic edifice
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Nekodake volcanic edifice
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Initial volcanic edifice
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[ Lower ]

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

Distribution: Summit of Mount Azumaya, Tsumagoi city, Agatsuma county, Gunma pref., The right bank of Takinoiri creek - The left bank of Daimyojin creek - Oni-iwa, Ueda city, Nagano pref.; summit of Mount Nekodake, Susaka city, Nagano pref.

Nishiki et al. (2014) Jour. Geol. Soc. Japan, vol.120, no.3, pp.89-103 DOI
Ota and Katada (1955) Suzaka, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 54p. (in Japanese with English abstract 6p.)