Nakanomata Mudstone Member

Nakanomata Mudstone Member Akahane, 1975

Type locality: Nakanomata river, Nakanomata, Joetsu city, Niigata prefecture
Coherent formation
Rift basin sediments
Pliocene (ca, 5 - 4.0 Ma)
Correlation: Nechi Formation

Sedimentary facies: Marine
Sedimentary facies: Basin slope - Basin floor
Sedimentary facies: Submarine fan (Muddy channel levee system type)
Lithofacies: Muddy turbidite
Lithofacies: Mudstone
Lithofacies (Minor): Mudstone-dominant interbedded sandstone and mudstone, Sandstone
Sedimentary structures: Slump structures

Thickness: 500 - 700 m
Upper limit: Conformity (Tsunako Conglomerate Member, Doguchi Alternation of Sandstone and Mudstone Member, Seto Tuff Member), Unconformity (Eboshiyama Volcanic Rocks)
Lower limit: Conformity (Minakuchi Alternation of Sandstone and Mudstone Member)

Nodani Formation
[ Upper ]
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Nakanomata Mudstone Member
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Minakuchi Alternation of Sandstone and Mudstone Member
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Yokobatake Alternation of Sandstone and Mudstone Member
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[ Lower ]

Nishikubiki Group
[ Upper ]
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Kawazume Formation
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Nodani Formation
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Nanbayama Formation
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[ Lower ]

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

Distribution: Nakanomata river - Gozu - Mount Kasuga - Kamitsunako - Nakanomata - Kitadani - Seto Joetsu city, Niigata pref.; Nogawa river, Itoigawa city, Niigata pref.
Fossils: family Odobenidae, Echinoids (Linthia nipponica), Sponges (Makiyama chitanii)
Fossils (Shellfishes): Acila (Truncacila) sp., Anadara (Anadara) amicula, Boreotrophon cf. solitarius, Buccinum sp., Clinocardium (Clinocardium) cf. fastosum, Conchocele sp., Crassostrea? sp., Cryptonatica janthostomoides, Dosinia (Phacosoma) sp., Epitonium (Boreoscala) greenlandicum, Euspira pila, Fulvia sp., Glycymeris (Glycymeris) yessoensis, Lucinoma acutilineata, Macoma (Macoma) calcarea, Mercenaria cf. chitaniana, Mizuhopecten yessoensis yessoensis, Naticidae gen. et sp. indet, Neverita (Glossaurax) didyma, Nuculana (Nuculana) pernula), Pandora sp., Panomya simotomensis, Pseudamiantis sp., Solemya sp., Solen krusensterni, Thyasira tokunagai, Turritella (Neohaustator) saishuensis motidukii, Yoldia (Cnesterium) notabilis

Takano (2011) Jour. Geol. Soc. Japan, vol.117, no.4, pp.238-258 DOI
Akahane and Kato (1989) Geology of the Takada-Seibu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 89p. (in Japanese with English abstract 3p.)