Pre-caldera stage

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Pre-caldera stage

Type locality: Oshima city, Tokyo
Volcanic rocks
Stratovolcano, Caldera volcano
late Pleistocene (older than 41,600 yBP, ¹⁴C)

Lithofacies: Low-alkaline tholeiite series
Lithofacies: Pigeonite series
Lithofacies: Olivine basalt, Pyroxene olivine basalt, Pyroxene basalt

Pre-caldera stage
[ Upper ]
~~~~~~~~~~~~~~
Younger edifice
~~~~~~~~~~~~~~
Older edifice
~~~~~~~~~~~~~~
[ Lower ]

Oshima volcano
[ Upper ]
~~~~~~~~~~~~~~
Post-caldera stage
~~~~~~~~~~~~~~
Syn-caldera stage
~~~~~~~~~~~~~~
Pre-caldera stage
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Oshima city, Tokyo

Isshiki (1984) Geology of the Oshima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 133p. (in Japanese with English abstract 5p.)