Ishiai Member

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Ishiai Member Sugiyama and Matsuda, 2014

Type locality: Ishiaigawa river, Ishiai, Nanbu city, Minamikoma county, Yamanashi prefecture
Coherent formation
Trough basin-fill deposit at the collision boundary between Izu-Bonin-Mariana arc and Southwest - East Japan island arc
Back-arc basin volcanic activity at the back-arc basin of Izu-Bonin-Mariana arc
late Miocene - Pliocene
Correlation: Takase Formation, Nakagochi Formation, Kawaino Member

Sedimentary facies: Marine
Lithofacies: Sandstone-dominant interbedded sandstone and mudstone
Lithofacies (Minor): Conglomerate
Lithofacies (Lower, Minor): Hornblende andeiste tuff breccia

Lower limit: Transitional, Interfingered (Kangatake Member)

Hamaishidake Formation (West)
[ Upper ]
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Okuyama Member / Kawaino Member
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[ Lower ]

Hamaishidake Formation (East)
[ Upper ]
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Ishiai Member
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Kangatake Member
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[ Lower ]

(Invalid name) Hamaishidake Group
[ Upper ]
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Kawaino Formation
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Nakagochi Formation
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Utsugino Formation
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Sattatoge Formation / Murono Formation
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Kogochi Formation
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[ Lower ]

Fujikawa Group (Central zone)
[ Upper ]
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Hamaishidake Formation / Akebono Formation
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Aimata Formation
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Kuonji Formation
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Hara Formation
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[ Lower ]

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

Distribution: Ishiaigawa river - Mukaida, Nanbu city, Minamikoma county, Yamanashi pref.; Nakagochigawa river, Aoi ward, Shizuoka city, Shizuoka pref.

Sugiyama and Matsuda (2014) Geology of the Nanbu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 134p. (in Japanese with English abstract 5p.)