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Umanokamiyama Formation Iizuka, 1930

Invalid synonym: lower Kodomari Formation, Bonju Formation

• Type locality: Mount Manogami, Goshogawara city, Aomori prefecture
• Coherent formation
• middle Miocene (Dinoflagellates)
• Correlation: Nishikurosawa Formation
• Intruded by: Rhyolite (14.1, 13.9 Ma, K-Ar)

• Lithofacies: Mudstone, Pumiceous tuff breccia, Basaltic lapilli breccia, Lava
• Lithofacies (Minor): Tuff

• Thickness: 1,100 m or thicker
• Upper limit: Bottom of Ota Pumiceous Volcaniclastic Rocks
• Upper limit: Conformity (Ota Pumiceous Volcaniclastic Rocks)
• Lower limit: Top of the sandstone bed of Nagane Formation
• Lower limit: Transitional (Nagane Formation), Unconformity (Fuyube Formation)

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

• Distribution: Kodomari, Nakadomari city, Kitatsugaru county, Aomori pref.; Mount Manogami, Goshogawara city, Aomori pref.; Mozawa, Kanagi town, Goshogawara city, Aomori pref.
• Fossils: Dinoflagellates
• Fossils (Shellfish): Scaphander? sp., Palliolum sp., Yoldia sp.
• Fossils (Foraminifera): Cyclammina sp., Haplophragmoides sp., Martinotiella communis, Globorotalia fohsi
• Fossils (Diatoms): Actinocyclus ehrenbergi var. tenella, Actinocyclus ingens, Actinocyclus tsugaruensis, Actinoptychus cfr. undulatus, Coscinodiscus elegans, Coscinodiscus endoi, Coscinodiscus marginatus, Coscinodiscus stellaris var. symbolophora, Coscinodiscus vetutissimus, Coscinodiscus yabei?, Denticulahustedtii, Denticula lauta, Denticula nicobarica, Fragilariopsis sp., Hemiaulus polymorphus, Medioria cfr. splendida, Melosira sulcata, Rouxia californica, Rouxia peragalli, Stephanogonia hanzawae, Stephanopyxis cfr. ferox, Stephanopyxis schenckii, Stephanopyxis turris, Thalassionema nitzschioides (= Thalassionema hirosakiensis), Thalassiosira haynaldiella, Xanthiopyxis spp.

• Nagamori et al. (2013) Geology of the Aomori-Seibu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 67p. (in Japanese with English abstract 4p.)
• Fujii (1981) Geology of the Aburakawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 38p. (in Japanese with English abstract 3p.)