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Shirone Formation (Minato et al., 1967) Kamoi et al., 2002

Invalid synonym: Kurotori Formation

• Coherent formation
• Barrier-Lagoon system, Delta system
• Pleistocene - Holocene (ca. 16 - 0 ka)
• Upper: Holocene (ca. 5 - 0 ka)
• Middle: Holocene (ca. 10 - 5 ka)
• Lower: Pleistocene (ca. 16 - 10 ka)

• Sedimentary facies (Upper): Lacustrine, Freshwater - Brackish, Marine
• Sedimentary facies (Upper): Sand dunes, Seashores, Rivers (Natural levees, Crevasse-splay, Sandbanks), Backmarsh, Interdune lowland
• Sedimentary facies (Middle): Lacustrine, Brackish, Marine
• Sedimentary facies (Middle): Lagoon, Rivers, Eolian dunes, Sand bars
• Sedimentary facies (Lower): Rivers, Freshwater, Brackish
• Lithofacies (Upper): Mud, Sands, Interbedded sand and mud
• Lithofacies (Upper, Minor): Humic soils
• Lithofacies (Middle): Sandy mud, Mud, Interbedded sand and mud, Sands
• Lithofacies (Lower): Sands, Interbedded sand and mud

• Thickness: ca. 53 - 154 m or thicker
• Lower limit: Unconformity (Kanbara Group, Nishikanbara Formation)

• Distribution: Niigata pref.
• Fossils (Shellfishes): Acteocina insignis, Acteocina koyasensis, Callista chinensis, Cantharus sp., Corbicula japonica, Crassostrea gigas, Ctena delicatula, Fluviocingula nipponica, Homatopoma amussiatum, Latirus sp., Macoma praetexta, Mangilia tabatensis, Mitrella yabei, Moerella sp., Odostmia hilgendorfi, Oliva mustelina, Olivella japonica, Patudinella japonica, Potamocorbula amurensis, Reticunassa festiva, Rhizorus acutaeformis, Ringicula dolialis, Ringicula yokoyamai, Saccella cf. sematensis, Turbonilla semicolorata, Turbonilla tokunagai, Umbonium costatum, Veremolpha micra, Wallucina lamyi
• Fossils (Foraminifera): Ammonia cf. beccari, Ammonia japonica, Bolivina robusta, Buccella aculeata, Buccella frigida, Buccella frigida callida, Cribrononion clavatum, Cribrononion subgranulosum, Elphidium subincertum, Nonion manpukujiense, Pseudorotalia gaimardii, Quinqueloculina sp., Siphogenerina raphonus
• Fossils (Diatoms): Aulacoseira granulata, Coscinodiscus sp., Cyclotella caspia, Delphineis surirella, Odontella aurita, Skeletonema costatum, Thalassiosira excentrica
• Tephra: As-K, Nm-NK

• Kamoi et al. (2016) Geology of the Niigata and Uchino District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 90p. (in Japanese with English abstract 2p.)