Koyabe Tuffaceous Sandstone and Mudstone Member

[ Top ] [ Japanese ]

Koyabe Tuffaceous Sandstone and Mudstone Member Eto, 1986

Type locality: Koyabe - Morisaki, Yokosuka city, Kanagawa prefecture
Accretionary complex
Miocene

Sedimentary facies: Marine
Depth of water: Upper bathyal (Foraminifera)
Lithofacies: Interbedded tuffaceous sandstone and mudstone

Thickness: 200 - 400 m
Upper limit: Unconformity (Miura Group)
Lower limit: Transitional (Sakaguchi Tuffaceous Sandstone Member)

Yabe Formation
[ Upper ]
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Koyabe Tuffaceous Sandstone and Mudstone Member
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Sakaguchi Tuffaceous Sandstone Member
::::::::::::::
[ Lower ]

Hayama Group
[ Upper ]
~~~~~~~~~~~~~~
Yabe Formation
::::::::::::::
Kinugasa Formation
/--/--/--/--/-
Oyama Formation
--------------
Abuzuru Formation
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Morito Formation
?--?--?--?--?-
[ Lower ]

Mineoka Belt (Miura peninsula)
[ Upper ]
~~~~~~~~~~~~~~
Miura Group
~~~~~~~~~~~~~~
Hayama Group
?--?--?--?--?-
[ Lower ]

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

Distribution: Koyabe - Morisaki - Sahara, Yokosuka city, Kanagawa pref.
Fossils (Foraminifera): Buliminella elegantissima, Globocassidulina cf. depressa, Stilostomella spp., Uvigerina sp.
Fossils (Radiolarians): Cyrtocapsella tetrapera
Fossils (Calcareous nannofossils): Coccolithus pelagicus, Discoaster deflandrei

Eto et al. (1998) Geology of the Yokosuka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 128p. (in Japanese with English abstract 3p.)