N4 Member

[ Top ] [ Japanese ]

N₄ Member

Type locality: Oshima city, Tokyo
Volcanic rocks
Stratovolcano, Caldera volcano
Holocene (8th century)

Lithofacies: Low-alkaline tholeiite series
Lithofacies: Pigeonite series
Lithofacies (Upper): Volcanic ash
Lithofacies (Lower): Basalt scoria fall deposit (several units)

Source: Odorichaya, Izuoshima island
Thickness (Lower): A few dozen m

Nomashi Formation
[ Upper ]
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N₁ Member
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N₂ Member
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N₃ Member
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N₄ Member
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[ Lower ]

Post-caldera stage
[ Upper ]
~~~~~~~~~~~~~~
Yuba Formation
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Nomashi Formation
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[ Lower ]

Oshima volcano
[ Upper ]
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Post-caldera stage
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Syn-caldera stage
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Pre-caldera stage
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[ 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.)