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Yokoyakyo Lavas

• Type locality: northern part of Mount Yatsugatake, Nagano prefecture
• Volcanic rocks
• Pleistocene - Holocene

• Lithofacies: Olivine hornblende orthopyroxene clinopyroxene dacite lava (more than 3 flow units)
• Lithofacies (Minor): Pyroclastic rocks, Mudflow deposit

• Source: Tengu-Toheki cliff
• Thickness: 80 m or thicker
• Thickness (A unit): a few - 40 m
• Upper limit: Unconformity (Tengudakechubu Lava, Lacustrine deposit, Mikaburiyama Welded Tuff, Tsumetayama Lava, Tateshinakogen Lava)
• Lower limit: Unconformity (Itokaya Pyroclastic Flow Deposit, Inagodake Pyroclastic Flow Deposit, Inagodake Lavas)

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

• Distribution: Shibukawa river - Naruiwa river - Shiraide - Natsuzawa hot spring - Shibunoyu hot spring - Karasawa hot spring, Chino city, Nagano pref.; Inagoyu hot spring - Shirakaba ridge, Komi city, Minamisaku county, Nagano pref.

• Nishiki et al. (2007) Jour. Geol. Soc. Japan, vol.113, no.5, pp.193-211 DOI
• Kawachi (1974) Geology of the Tateshinayama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 114p. (in Japanese with English abstract 5p.)