Kogochi Formation

[ Top ] [ Japanese ]

Kogochi Formation Shiba and Suruga Bay Collaborative Research Group, 1986

Probably this should be redefined to Member of Hamaishidake Formation

Invalid synonym: Kogochi Group

Coherent formation
Trough basin (Fujikawa Trough) -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

Sedimentary facies: Marine
Lithofacies: Mudstone-dominant interbedded sandstone and mudstone

Thickness: 250 m or thicker

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: Okitsu river - Kogochi river, Shimizu ward, Shizuoka city, Shizuoka pref.
Fossils (Foraminifera): Globigerina bulloides, Globigerina decoraperla, Globigerina falconensis, Globigerina nepenthes, Globigerinita glutinata, Globigerinoides conglobatus, Globigerinoides extremus, Globigerinoides obliquus obliquus, Globigerinoides sacculifer, Globigerinoides trilobus, Globoquadrina altispira, Globorotalia hirsuta, Globorotalia menardii, Globorotalia miozea conoidea, Globorotalia scitula, Globorotaria tumida tumida, Neogloboquadrina acostaensis, Orbulina universa, Pulleniatina primalis, Sphaeroidinellopsis seminulina, Sphaeroidinellopsis subdehiscens

Sugiyama and Shimokawa (1990) Geology of the Shimizu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 103p. (in Japanese with English abstract 8p.)
Sugiyama et al. (1982) Geology of the Shizuoka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 82p. (in Japanese with English abstract 9p.)