[ Top ] [ Japanese ]

Omatsuzawa Formation (Kitamura, 1980) Ishii et al., 1982

Invalid synonym: Koganehasama Formation

• Type locality: Kamimachi, Omatsuzawa, Osato city, Kurokawa county, Miyagi prefecture
• Coherent formation
• Miocene
• Contemporaneous heterotopic facies: Nanakita Formation
• Correlation: Tsunaki Formation, Nagao Formation

• Sedimentary facies: Marine
• Lithofacies: Silty sandstone
• Lithofacies (Minor): sandy siltstone, Tuffaceous siltstone, Tuff
• Sedimentary structures: Cross stratification, Bioturbation, Pipe rocks

• Thickness: 50 - 150 m
• Upper limit: Unconformity (Kameoka Formation, Embana Formation)
• Lower limit (Upper Member): Top of the sandstone showing cross stratification
• Lower limit: Conformity (Aoso Formation, Upper Member, Oido Formation)

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

• Distribution: Kamimachi - Ishihara, Omatsuzawa, Osato city, Kurokawa county, Miyagi pref.; Akida - Mitsui - Sawama, Sanbongi, Osaki city, Miyagi pref.; Ochiai, Taiwa city, Kurokawa county, Miyagi pref.; Koganehasama, Wakuya city, Toda county, Miyagi pref.; Mount Nonodake, Wakuya city, Toda county, Miyagi pref.; Mount Kagobo - Shimozawa - tsugihashi, Osaki city, Miyagi pref.
• Fossils (Shellfishes): Dosinia sp., Glycymeris matumoriensis, Mizuhopecten kagamianus, Pecten sp., Placopecten akhoensis, Placopecten wakuyaensis
• Fossils (Diatoms): Actinocyclus ehrenbergi, Actinocyclus ellipticus, Actinocyclus ingens, Actinoptychus undulatus, Amphora spp., Anaulus sp., Aulacosira granulata, Auliscus spp., Bacillaria paradoxa, Biddulphia aurita, Biddulphia calmus, Cocconeis californica, Cocconeis costata, Cocconeis scutellum, Cocconeis vitrea, Coscinodiscus endoi, Coscinodiscus marginatus, Coscinodiscus nitidus, Coscinodiscus oculus-iridis, Coscinodiscus cf. obscurus, Coscinodiscus symbolophorus, Coscinodiscus temperi, Coscinodiscus vetulissimus, Coscinodiscus yabei, Cussia paleacea, Delphineis surirella, Denticulopsis dimorpha, Denticulopsis hustedtii, Denticulopsis hyalina, Denticulopsis lauta, Denticulopsis nicobarica, Denticulopsis praedimorpha, Diploneis spp., Goniothecium rogersii, Goniothecium tenue (<= Ikebea spp.), Grammatophora angulosa, Hantzschia amphioxis, Hemiaulus polymorphus, Hemidiscus cuneiformis, Kisseleviella carina, Mediaria splendida, Melosira sol, Melosira sulcata, Navicula spp., Nitzschia fossilis, Nitzschia pliocena, Opephora spp., Plagiogramna staurophorum, Pseudopodosira elegans, Pseudopodosira aff. hyalina, Pterotheca subulata, Raphoneis surirella, Rhabdonema cf. crassam, Rhaphoneis amphiceros, Rhizosolenia alata, Rhizosolenia barboi, Rhizosolenia miocenica, Rhizosolenia styliformis, Rossiella praepaleacea, Rossiella tatsunokuchiensis, Rouxia californica, Rouxia peragallii, Stephanodiscus? sp., Stephanopyxis turris, Stictodiscus californicus, Stictodiscus kittonianus, Synedra cfr. jouseana, Synedra miocenica, Thalassionema hirosakiensis, Thalassionema nitzschioides, Thalassiosira antiqua, Thalassiosira borealis, Thalassiosira leptopus, Thalassiosira manifesta, Thalassiosira nidulus, Thalassiothrix longissima
• Tephra: K11, K12, K13, K14, K15, O2, O6, O8, O10

• Kitamura et al. (1983) Geology of the Yoshioka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 50p. (in Japanese with English abstract 5p.)
• Ishii et al. (1982) Geology of the Matsushima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 121p. (in Japanese with English abstract 9p.)
• Kitamura et al. (1981) Geology of the Furukawa District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 32p. (in Japanese with English abstract 4p.)
• Takahashi and Matsuno (1969) Geology of the Wakuya District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 26p. (in Japanese with English abstract 6p.)