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Lower Formation

• Back-arc basin (Yakuno Ophiolite)
• Coherent formation
• Mata-mafic rocks: early Permian, Sakmrian - Roadian (290 - 280 Ma, Rb-Sr)
• Correlation: Omoriyama Formation

• Sedimentary facies: Marine
• Lithofacies: Meta-gabbro, Tonalite, Mafic lava, Mafic tuff
• Lithofacies (Minor): Mudstone

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

• Distribution: Kyoto pref.; Ibara city, Okayama pref.

• Sato et al. (2022) Geology of the Wake District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, AIST, 106p. (in Japanese with English abstract 4p.)
• Takemura et al. (2009) Jour. Geol. Soc. Japan, vol.115, Supplement, pp.123-137 DOI