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Ryuso Group (Koike, 1957) Sugiyama, 1995

Invalid synonym: Ryuso Sheet, Ryuso Sheet, Ryusozan Formation, Takakusayama Group (Takakusayama Volcanic Rocks and Ryuso Volcanic Rocks)

• Accretionary complex
• middle Miocene (Radiolarians, Foraminifera)
• Intruded by: Dolerite, Quartz diorite

• Sedimentary facies: Marine
• Sedimentary facies: Trench-fill deposit at the trench and the oceanic side slope of accretionary complex
• Lithofacies (Upper): Rhyolite, Dacite, Alkaline basalt lava, Lapillistone
• Lithofacies (Lower): Mudstone, Tuff

• Thickness: 950 m or thicker
• Distribution (South-North): ca. 50 km
• Distribution (Width): 1.5 - 3 km

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

• Distribution: Mount Jumaisan, Yamanashi pref. - Shizuoka pref.; Mount Ryusosan - Mount Mafujiyama - Sendai - Kagoue, Aoi ward, Shizuoka city, Shizuoka pref.; Mariko - Okuzure seashore, Suruga ward, Shizuoka city, Shizuoka pref.; Harukigawa river, Hayakawa city, Minamikoma county, Yamanashi pref.
• Fossils (Radiolarians): Calocycletta cf. virginis, Carpocanopsis? sp., Cyclampterium? sp., Cyrtocapsella cornuta, Cyrtocapsella tetrapera, Didymocyrtis cf. violina, Eucyrtidium cf. cienkowskii, Spongurus? spp., Stichocorys delmontensis, Stichocorys wolffii, Stylodictya? sp., Theocyrtis? sp., Tholospyris? sp.
• Fossils (Foraminifera): Ammonia sp., Bathysiphon sp., Cribrostomoides sp., Dorothia sp., Eggerella bradyi, Elphidium sp., Globigerina angustiumbilicata, Globigerina praebulloides, Globigerina venezuelana, Globigerinoides trilobus, Globorotalia peripheroronda, Globorotalia siakensis, Globorotalia quinifalcata, Hornosina sp., Martinottiella communis, Melonis pompilioides, Nodosaria sp., Praeorbulina glomerosa, Globoquadrina altispira, Sigmoilopsis schlumbergeri, Sphaeroidinellopsis disjunctus, Spirosigmoilinella compressa, Stilostomella spp.

• Ozaki and Sugiyama (2018) Geology of the Minobu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 169p. (in Japanese with English abstract 7p.)
• Sugiyama and Matsuda (2014) Geology of the Nanbu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 134p. (in Japanese with English abstract 5p.)
• Sugiyama and Shimokawa (1990) Geology of the Shimizu District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 103p. (in Japanese with English abstract 8p.)
• Sugiyama et al. (1982) Geology of the Shizuoka District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 82p. (in Japanese with English abstract 9p.)