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Ichiyanagi Mine

Hirukawa, Nakatsugawa city, Gifu pref., Japan


Togane Mine, Ichiyanagi adit


Pneumatolytic deposit

Pneumatolytic deposit near the boundary between the Late Cretaceous (75 Ma) Nohi Rhyolite and the Late Cretaceous (70 Ma) Naegi-Agematsu Granite intruded in it. The Nohi Rhyolite is composed of ryolitic to dacitic welded tuff, and considered as the pyroclastic flow from the Cretaceous Ena Caldera. The Naegi-Agematsu Granite is S-type (Ilmenite-series), and considered as plutonic rock related to the Ena Caldera. Ages of igneous rocks were determined by the fission track dating of zircon.

Ichiyanagi Mine

Outcrop of löllingite-bearing quartz veins in the Nohi Rhyolite. Veins can be followed more than several tens of meters, and are wider at the bottom of the outcrop than those at the top. Veins are ferberite-rich at the bottom, löllingite-rich at the middle, and rich in greisen minerals such as topaz and siderophyllite at the upper part. The vein of this photograph is several tens of cm in width, and composed mainly of löllingite, ferberite and minor amount of quartz. Wall rock is very hard greisen. Note that there is no specific structure at the boundary between the vein and the wall rock. The part with wavy surface at the lower right is scorodite crusts formed by weathering of löllingite.

Reported Minerals

Mineral Assemblages

  • Löllingite - Quartz - Parasymplesite - Scorodite
  • Löllingite - Arsenopyrite - Quartz - Ferberite
  • Quartz - Protolithionite - Topaz

Details of the mine

It is said that this pit mouth was mined temporary as a part of neighbouring Tougane Mine.

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