S' Member

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S' Member

Type locality: Oshima city, Tokyo
Volcanic rocks
Stratovolcano, Caldera volcano
Holocene (6th century?)

Lithofacies: Low-alkaline tholeiite series
Lithofacies: Pigeonite series
Lithofacies: Pyroxene basalt, Olivine basalt
Lithofacies: Volcanic ash
Lithofacies (Basal): Scoria fall deposit

Mode of eruption: Explosion
Distribution: 10 km² or less
Thickness: ca. 50 cm
Upper limit: Unconformity (S₁ Member)

Syn-caldera stage
[ Upper ]
~~~~~~~~~~~~~~
S₁ Member
~~~~~~~~~~~~~~
S' Member
~~~~~~~~~~~~~~
S₂ Member
~~~~~~~~~~~~~~
[ 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.)