Mera Formation

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Mera Formation (Kotake, 1988) Kawakami and Shishikura, 2006

Invalid synonym: Minamiasai Formation

Type locality: Mera fishign harbour, Tateyama city, Chiba prefecture
Coherent formation
Trench fill sediments, Landward slope basin of trench
late Pliocene - early Pleistocene (3.31 - 1.21 Ma)
Contemporaneous heterotopic facies: lower - middle Hata Formation

Sedimentary facies: Marine
Lithofacies: Siltstone-dominant interbedded scoriaceous sandstone and siltstone
Sedimentary structures: Parallel stratification

Thickness: 200 - 300 m
Upper limit: Conformity (Hata Formation)
Lower limit: Transitional (Shiramazu Formation), Unconformity (Nishizaki Formation, Hedate Formation)

Mera Formation
[ Upper ]
--------------
Rendaiji Conglomerate Member
--------------
[ Lower ]

Chikura Group (Northern part)
[ Upper ]
?--?--?--?--?-
Negata Formation
--------------
Sagashi Formation
?--?--?--?--?-
[ Lower ]

Chikura Group
[ Upper ]
?--?--?--?--?-
Hata Formation
-------'''/,,,
Mera Formation
--------------
Shiramazu Formation
--------------
Shirahama Formation
?--?--?--?--?-
[ Lower ]

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

Distribution: Mera fishign harbour - Osaba, Tateyama city, Chiba pref.; Oikura, Chikura town, Minamiboso city, Chiba pref.; Takiguchi, Shirahama town, Minamiboso city, Chiba pref.
Fossils: Foraminifera, Radiolarians, Diatoms, Calcareous nannofossils (Reticulofenestra minutula), Trace fossils
Tephra: YK, OA, TY, HF, HS, NY

Utagawa et al. (2017) Jour. Geol. Soc. Japan, vol.123, no.11, pp.969-976 DOI
Okada et al. (2012) Jour. Geol. Soc. Japan, vol.118, no.2, pp.97-108 DOI
Kawakami and Shishikura (2006) Geology of the Tateyama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 82p. (in Japanese with English abstract 5p.)