TrekGEO > Mineral Trail > Koshinetsu region > Yamanashi pref. > Takemori

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Enzan-Takemori, Koshu city, Yamanashi pref., Japan

"No Trespassing" sign was erected


Pneumatolytic deposit

Alpine fissure in hornfels, shale of the Shimanto accretionary complex subjected to Albite-Epidote-hornfels facies metamorphism by the late Miocene (10 Ma) Tokuwa Granite. Granite at this locality is the S-type (Ilmenite-series) margin of the I-type (Magnetite-series) Tokuwa Granite. The S-type (Ilmenite-series) margin was formed by reduction reation of granite magma with surrounding pelitic rocks. The shale of this locality is that of the Shimanto accretionary complex, probably the middle Eocene (45 Ma) Gongenyama Unit of the Sagamiko Group. Approximately 1 km apart from the Tokuwa Granite, the heat source. Ages of sedimentary rocks were determined by radiolarians, and granite age by K-Ar radiometric dating of biotite and whole rock.

Reported Minerals

Mineral Assemblages

  • Quartz - Anatase - Brookite - Rutile
  • Quartz - Muscovite - Dravite
  • Quartz - Sulphur
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