Okuyama Member

[ Top ] [ Japanese ]

Okuyama Member Sugiyama and Matsuda, 2014

Type locality: Hyozawa creek, Oborazawa, 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
Interfingered: Kawaino Member

Sedimentary facies: Marine
Depth of water: Upper - Middle bathyal
Lithofacies: Mudstone, Mudstone-dominant interfingered sandstone and mudstone
Lithofacies (Minor): Tuffaceous sandstone
Lithofacies (Lower, Minor): Dacite tuff

Lower limit: Conformity (Shinoisan Member)

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

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

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

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

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

Distribution: Okuyama hot spring - Mount Shinoisan - Oborazawa, Nanbu city, Minamikoma county, Yamanashi pref.
Fossils: Foraminifera (Globorotalia tumida tumida)
Fossils (Calcareous nannofossils): Amaurolithus delicatus, Amaurolithus tricorniculatus, Calcidiscus leptoporus, Calcidiscus machintyrei, Coccolithus pelagicus, Cyclolithella annula, Dictyococcites productus, Discoaster brouweri, Discoaster variabilis, Discolithina spp., Helicosphaera carteri, Reticulofenestra gelida, Reticulofenestra haqii, Reticulofenestra minuta, Reticulofenestra minutula, Reticulofenestra pseudoumbilica, Sphenolithus abies, Sphenolithus moriformis, Triquetrorhabdulus rugosus

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.)