Hata Formation

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Hata Formation (Naruse et al., 1951) Kawakami and Shishikura, 2006

Invalid synonym: Mano Formation, Kanamari Formation

Type locality: Komatsu forest road, Minamiboso city, Chiba prefecture
Coherent formation
Trench fill sediments, Landward slope basin of trench
late Pliocene - early Pleistocene (1.95 - 0.85 Ma)
Contemporaneous heterotopic facies (Upper): lower Kamo Formation
Contemporaneous heterotopic facies (Lower - Middle): Mera Formation
Correlation: Anno Formation

Sedimentary facies: Marine
Lithofacies: Interbedded tuffaceous sandstone and tuffaceous siltstone
Lithofacies (Minor): Pumice, Scoria
Sedimentary structures: Slump structures

Thickness: 300 - 400 m
Upper limit: Unconformity (Kamo Formation)
Lower limit: Transitional (Shiramazu Formation), Conformity (Mera Formation), Unconformity (Nishizaki Formation)

Hata Formation
[ Upper ]
--------------
Nagaogawa Sandstone Member
--------------
[ Lower ]

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

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

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

Distribution: Komatsu forest road - Kashio, Chikura town, Minamiboso city, Chiba pref.
Fossils: Foraminifera, Radiolarians, Diatoms, Calcareous nannofossils (Discoaster brouweri, Reticulofenestra asanoi)
Tephra: TY, HF, HS = HS, NY, Ny-5, BW, MS, Kd38

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.)