Okuzure Formation

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Okuzure Formation (Koike, 1949) Suzuki et al., 1990

Type locality: Okuzure, Kyonan city, Awa county, Chiba prefecture
Coherent formation
Basal conglomerate of Awa Group
Miocene
Interfingered: Okuyama Formation, lower Nakaobara Formation
Intruded by: Basalt

Sedimentary facies: Marine
Lithofacies: Breccia
Lithofacies (Minor): Interbedded sandstone and conglomerate, Sandstone

Thickness: 300 m
Upper limit: Transitional (Okuyama Formation)
Lower limit: Unconformity (Hota Group)

(Invalid synonym) Sakuma Group
[ Upper ]
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Nakaobara Formation
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Okuyama Formation
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Okuzure Formation
~~~~~~~~~~~~~~
[ Lower ]

Awa Group (Western part)
[ Upper ]
~~~~~~~~~~~~~~
Annno Formation
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Kiyosumi Formation
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Amatsu Formation
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Kinone Formation
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Sakuma 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: Okuzure - Okuyama - Kamisakuma - Nakasakuma - Ezuki, Kyonan city, Awa county, Chiba pref.; Homyo - Hoteigo, Kamogawa city, Chiba pref.; Toriikawa - Ishohatake, Minamiboso city, Chiba pref.; Kanbata, Futtsu city, Chiba pref.
Fossils (Shellfishes): Chlamys akihoensis, Chlamys vesiculosa, Conus sp.

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.)