Aokiyama Formation

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Aokiyama Formation Suzuki et al., 1990

Type locality: Shinden? river, Namuya, Tomiura city, Minamiboso city, Chiba prefecture
Accretionary complex
Miocene

Sedimentary facies: Marine
Lithofacies: Mudstone
Lithofacies (Minor): Sandstone, Tuff

Thickness: 1,200 m or thicker
Upper limit: Bottom of the sandstone intercalating horizon
Upper limit: Conformity (Tomiyama Formation, Iwaibukuro Formation)
Lower limit: Top of the sandstone and tuff-rich horizon
Lower limit: Transitional (Masuma Formation)

Hota Group (Western part)
[ Upper ]
~~~~~~~~~~~~~~
Ezuki Formation
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Tomiyama Formation
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Aokiyama Formation
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Masuma Formation
::::::::::::::
[ Lower ]

Hota Group (Eastern part)
[ Upper ]
~~~~~~~~~~~~~~
Emi Formation
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Nabuto Formation
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Takazuru Formation
--------------
Furubo Formation
~~~~~~~~~~~~~~
[ Lower ]

Mineoka Belt (Boso peninsula)
[ Upper ]
~~~~~~~~~~~~~~
Awa Group / Minamiboso Group
~~~~~~~~~~~~~~
Hota Group
::::::::::::::
Mineoka Group
?--?--?--?--?-
[ Lower ]

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

Distribution: Namuya, Tomiura city, Minamiboso city, Chiba pref.; Otsuka - Tomiyama, Tomiyama, Minamiboso city, Chiba pref.
Fossils (Silicoflagellates): Corbisema triacantha

Takahashi et al. (2016) Jour. Geol. Soc. Japan, vol.122, no.8, pp.375-395, DOI
Suzuki et al. (1990) Geology of the Nago District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 48p. (in Japanese with English abstract 3p.)