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Gamaharazawa Formation Shiraishi, 1992

• Type locality: Gamaharazawa creek, Otari city, Kitaazumi county, Nagano prefecture
• Coherent formation
• Early Jurassic (189 Ma, U-Pb)
• Correlation: Jogodani Formation, Douden Formation

• Sedimentary facies (Upper): Marine
• Sedimentary facies (Lower): Fluvial
• Lithofacies (Upper): Sandy mudstone, Felsic tuff
• Lithofacies (Upper, Minor): Sandstone, Conglomerate, Coal
• Lithofacies (Lower): Conglomerate, Sandstone
• Lithofacies (Lower, Minor): Mudstone, Felsic tuff
• Sedimentary structures (Lower): Imbrication, Planar cross-stratification, Trough cross-stratification, Current ripples

• Thickness: ca. 170 - 700 m
• Upper limit: Conformity (Bottom of the thick sandstone bed)
• Upper limit: Conformity (Odokorogawa Formation)
• Lower limit: Unconformity (Renge Metamorphic Rocks)

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

• Distribution: Gamaharazawa creek - Tsunzawa creek - Yubarazawa creek - Mount Ichinanbayama, Otari city, Kitaazumi county, Nagano pref.; Norikurazawa creek, Hakuba city, Kitaazumi county, Nagano pref.; Kotaki river - Hiwadaira - Odokorogawa river - Yogurazawa creek - Mount Gorinzan - Mount Akahageyama - Tsugadaira, Itoigawa city, Niigata pref.

• Takeuchi et al. (2017) Jour. Geol. Soc. Japan, vol.123, no.5, pp.335-350 DOI
• Takeuchi et al. (2015) Jour. Geol. Soc. Japan, vol.121, no.7, pp.193-216, DOI
• Nagamori et al. (2010) Geology of the Kotaki District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 130p. (in Japanese with English abstract 4p.)
• Nakano et al. (2002) Geology of the Shiroumadake District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 105p. (in Japanese with English abstract 5p.)