Usami volcano

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Usami volcano (Kuno, 1952) Oikawa and Ishizuka, 2011

Invalid synonym: Aharada Andesite

Type locality: southeast of Mount Sukumoyama - Gyoja fall, Ito city, Shizuoka prefecture; Chojagahara, Izunokuni city, Shizuoka prefecture
Volcanic rocks
Stratovolcano
Pleistocene (0.8 - 0.75 Ma)
Intruded by: Basalt - Andesite dike

Sedimentary facies: Marine
Lithofacies: Tholeiite
Lithofacies: Olivine orthopyroxene clinopyroxene basalt, Basaltic andesite
Lithofacies (Minor): Dacite
Lithofacies: Basalt - Andesite lava, Scoriaceous pyroclastic breccia, Tuff breccia

Source: east of Mount Sukumoyama
Thickness (Lava, A unit): Several m or thicker
Upper limit: Unconformity (Osaki volcano, Ajiro volcano, Sukumoyama volcano, Chojyagahara maar)

Usami-Taga volcanoes
[ Upper ]
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Hatsushima volcano
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Ajiro volcano
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Uomisaki volcano
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Atami volcano
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Osaki volcano
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Usami volcano
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Shimotaga volcano
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[ Lower ]

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

Distribution: southeast of Mount Sukumoyama - Gyoja fall - Aharada, Ito city, Shizuoka pref.; Chojagahara, Izunokuni city, Shizuoka pref.; Usami - Tanohara, Ito city, Shizuoka pref.; Numazu city, Shizuoka pref.; Shuzenji, Izu city, Shizuoka pref.

Oikawa and Ishizuka (2011) Geology of the Atami District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 61p. (in Japanese with English abstract 3p.)