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Minatomachi Formation

• Volcanic rocks
• early Miocene (18.2 Ma, K-Ar)

• Sedimentary facies: Subaqueous volcanic rocks
• Lithofacies: Breccia, Andesite lava
• Lithofacies (Minor): Mudstone

• Thickness: 34 m or thicker
• Lower limit: Unconformity? (Rebun Group)

• Distribution: Minatomachi, Rishirifuji city, Rishiri county, Hokkaido

• Ueki and Kondo (2010) Jour. Geol. Soc. Japan, vol.116, no.8, pp.437-440 DOI