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Kitamukai-Jizo

Gongendo, Moroyama city, Iruma county, Saitama pref., Japan

Occurrence

Oxidation zone of Pumpellyite-Aclinolite facies bedded manganese deposit

Manganese dioxide deposit formed by oxidation of chert-hosted bedded manganese deposit in a chert block of the Early Cretaceous (130 Ma) Kashiwagi unit, a member of the Northern Chichibu accretionary complex. The kashiwagi unit has been subjected to Pumpellyite-Actinolite facies metamorphism as a low grade part of the Sambagawa metamorphic belt in the Late Cretaceous (100 Ma). The age of chert is Permian Guadalupian (270 Ma) or Late Jurassic (145 Ma). Ages of sedimentary rocks were determined by radiolarians, and metamorphic age by K-Ar or Ar-Ar radiometric dating of muscovite.

Kitamukai-Jizo

A prospected adit on a small block of bedded chert of the Kashiwagi Unit. There is no record on this adit. It is possible that this is a part of Nakano-Tsuchiyama Mine located near by.

Reported Minerals

  • Manganese dioxide
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