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Suwa Mine

Kitayama, Chino city, Nagano pref., Japan


Bog iron deposit

Goethite-Jarosite deposit, Bog iron deposit, formed from the Fe- and SO4-rich hot spring on the Middle Pleistocene (133 ka) Tateshina-Kogen lava. Goethite is still depositing in a part of the territory. The Tateshina-Kogen Lava was erupted from Mount Yatsugatake. It is considered that goethite was deposited by bacterial iron biomineralization of Fe ion in the hot spring water.

Suwa Mine

Outcrop of Bog Iron, Goethite-Jarosite deposit. The brown part is spongy goethite. The yellowish part is rich in jarosite. There are many plant impression fossils in goethite.

Reported Minerals

  • Goethite
  • Jarosite
  • Cacoxenite
  • Koninckite
  • Strengite
  • Tinticite

Mineral Assemblages

  • Goethite - Jarosite
  • Goethite - Cacoxenite
  • Goethite - Koninckite
  • Goethite - Strengite
  • Goethite - Tinticite


  • 1940-1945: Fe was mined during World War II.


Related Occurrences

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