[ Top ] [ Japanese ]

Minamishirado Formation Nemoto et al., 1996

Invalid synonym: Minamishirado Member of Nakayama Formation

• Type locality: Minamishirado, Taira, Iwaki city, Fukushima prefecture
• Coherent formation
• southern Yezo Forearc basin (Jobanoki basin)
• early Miocene (15.9 Ma, FT)

• Sedimentary facies (Upper): Marine (Diatoms)
• Sedimentary facies (Lower): Brackish, Fluvial (Diatoms)
• Sedimentary facies (Top): Inner shelf
• Sedimentary facies (Upper): Lower shoreface, Ravinement erosion surface
• Sedimentary facies (Lower): Flood plain, Tidal flat, Estuary
• Climate (Upper): Tropical - Subtropical
• Lithofacies: Tuffaceous sandy siltstone, Tuffaceous sandstone, Tuff
• Lithofacies (Top): Sandstone
• Lithofacies (Upper): Sandstone, Gravelly sandstone
• Lithofacies (Lower): Mudstone
• Lithofacies (Lower, Minor): Mudstone
• Lithofacies (Minor): Felsic tuff
• Sedimentary structures (Upper, Minor): Cross stratificaiton
• Sedimentary structures (Lower): Cross stratificaiton

• Thickness: 90 - 220 m or thicker
• Thickness (Upper): ca. 12 - 16 Ma
• Upper limit: Unconformity (Kamitakaku Formation)
• Lower limit: Conformity (Yoshinoya Formation), Unconformity (Mizunoya Formation, Kamenoo Formation, Honya Formation)

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

• Distribution: Minamishirado - Nakayama, Taira, Iwaki city, Fukushima pref.; Narukouchi - Tateishi, Naraha city, Futaba county, Fukushima pref.; Mount Ishimori, Iwaki city, Fukushima pref.
• Fossils (Upper, Lower Kadonosawa fauna): Apolymetis? sp., Batillaria tateiwai, Dentalium sp., Dosinia nagaii, Dosinia nomurai, Glycymeris junghuhunii, Lucinoma cf. acutilineata, Lucinoma kamenooensis, Macoma tokyoensis, Mactra sp., Meretrix arugai, Nassarius simizui, Ostrea sp., Polinices meisensis, Saccella kongiensis, Siliqua cfr. pulchella, Solen sp., Spisula nakayamana, Turritella s-hataii, Venericardia siogamensis, Venerupis siratoriensis, Vicarya sp.
• Fossils (Lower, Daijima-type flora):
• Fossils (Diatoms): Achnanthes sp., Actinocyclus sp., Actinoptychus senarius, Aulacodiscus sp., Aulacoseira sp., Biddulphia sp., Coscinodiscus marginatus, Navicula sp., Paralia sulcata, Pinnularia sp., Rhaphoneis sp., Stephanopyxis spp., Tetracyclus sp., Thalassionema nitzschioides, Trochosira cf. convava

• Ando et al. (2011) Jour. Geol. Soc. Japan, vol.117, Supplement, pp.49-67 DOI
• Kubo et al. (2002) Geology of the Kawamae and Ide District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 136p. (in Japanese with English abstract 6p.)
• Kano et al. (1973) Geology of the Takanuki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 109p. (in Japanese with English abstract 6p.)