Pre-caldera cone

Pre-caldera cone Isshiki, 1959

Type locality: Mount Higashiyama, Hachijo city, Tokyo
Volcanic rocks
Stratovolcano
Pleistocene - Holocene
Intruded by: Andesite dike

Lithofacies: Tholeiite series
Lithofacies (Younger stage): Olivine basalt, Augite olivine basalt
Lithofacies (Younger stage, Minor): Hypersthene-bearing augite olivine basalt, Hypersthene olivine-bearing basalt, Augite hypersthene andesite
Lithofacies (Younger stage): Basalt lava, Olivine hypersthene augite andesite pumice flow deposit
Lithofacies (Younger stage, ): Charcoal
Lithofacies (Older stage): Olivine basalt, Augite olivine basalt
Lithofacies (Older stage, Minor): Hypersthene augite olivine basalt, Olivine augite andesite, Olivine hypersthene andesite, Augite andesite, Olivine augite andesite, Augite andesite, Hypersthene augite andesite
Lithofacies (Older stage): Lava, Volcaniclastic rocks, Mudflow deposit

Thickness (A unit, Lava): Some dozen m
Lower limit: Unconformity (Yokomagaura volcano)

Higashiyama volcano
[ Upper ]
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Parasitic crater / Central cone
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Post-caldera cone
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Pre-caldera cone
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[ Lower ]

Hachijojima volcano
[ Upper ]
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Nishiyama volcano
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Higashiyama volcano
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Old volcanoes
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[ Lower ]

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

Distribution: Yokomagaura - Osaka tunnel - Yokoze - Imanegahana - Ohirakata - Igona - Nakonohana - Okazato - Ishizumigahana, Hachijo city, Tokyo
Fossils (Younger stage): Leaves
Fossils (Older stage): Machilus thunbergi (Tree trunk), Leaves

Isshiki (1958) Hachijo-jima, Explanatory Text of the Geological Map of Japan, Scale 1:50,000, Geological Survey of Japan, 58p. (in Japanese with English abstract 5p.)