Utsutoge Formation

Utsutoge Formation (Morita, 1930 ex Yabe and Hatai, 1941) Minakawa, 1959

Type locality: Utsu pass, Iide city, Nishiokitama county, Yamagata prefecture
Coherent formation
late Miocene

Sedimentary facies: Marine?
Lithofacies (Upper): Sandstone
Lithofacies (Lower): Muddy sandstone
Lithofacies (Lower, Minor): Felsic tuff
Sedimentary structures (Upper): Trough cross-stratification, Planar cross-stratificaiton
Sedimentary structures (Lower): Bioturbation

Thickness: ca. 20 - 420 m
Upper limit: Bottom of Saitsu Pyroclastic Flow Deposit
Upper limit: Conformity (Takamine Formation)
Lower limit: Bottom of the sandstone and conglomerate-dominant horizon
Lower limit: Conformity, partly unconformity (Yugoya Formation)

Oguni, Yamagata pref.
[ Upper ]
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Takamine Formation
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Utsutoge Formation
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Yugoya Formation
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Numazawa Formation
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Myozawabashi Formation
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Meganebashi Formation
~~~~~~~~~~~~~~
Kitaoguni Formation
~~~~~~~~~~~~~~
[ Lower ]

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

Distribution: Utsu pass - Utsuzawa river - Osotani river, Iide city, Nishiokitama county, Yamagata pref.
Fossils: Foraminifera (Cassidulina japonica, Cribroelphidium yabei), Trace fossils (Rosselia isp.)
Fossils (Older Shiobara-Yama fauna): Anadara sp., Buccinum leucostoma, Buccinum sinanoense, Clinocardium californica, Clinocardium ciliatum, Clinocardium iwasiroense, Clinocardium shinjiense, Conchocele nipponica, Cryptonatica janthostomoides, Cryptonatica janthostomoides yamagatana, Fabulina pallidula, Felaniella usta, Fulvia sp., Gemmulifusus? sp., Glycymeris sp., Lucinoma acutilineatum, Lucinoma murakawai, Lucinoma otukai, Macoma calcarea, Macoma tokyoensis, Meretrix uzenensis, Miyagipecten matsumoriensis, Mizuhopecten kimurai, Mizuhopecten matumoriensis, Mohnia yanamii, Mya cuneiformis, Mya urusikoboana, Nanaochlamys notoensis otutumiensis, Naticid operculum, Peronidea cf. protovenulosa, Serripes laperousii, Serripes yokoyamai, Siphonalia sp., Spisula grayana, Trophonopsis hondai, Turritella (Idaella) tanaguraensis, Yoldia (Yoldia) yabei

Yamanoi et al. (2008) Jour. Geol. Soc. Japan, vol.114, no.5, pp.262-266 DOI
Yanagisawa and Yamamoto (1998) Geology of the Tamaniwa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 94p. (in Japanese with English abstract 4p.)