Kawai Mine

Closed to collecting

Occurrence

Moderate-T hydrothermal skarn deposit

Moderate temperature hydrothermal deposit in skarn formed by the granite porphyry dike of the Late Cretaceous (70 Ma) Himeguri Granite intruded in the Middle Jurassic (165 Ma) Kamiaso unit, a member of the Tamba-Mino-Ashio accretionary complex. Skarn was formed by contact metamorphism of the Himeguri Granite or the middle Paleocene (60 Ma) Ena-Agematsu Granite. The Himeguri Granite and the Ena-Agematsu Granite are S-type (Ilmenite-series). Approximately 2 km apart from the Ena body of the Ena-Agematsu Granite. The sulfide deposit is in contact with the granite porphyry dike of the Himeguri Granite. The Himeguri Granite is the arc-shaped dike at the northern margin of the Cretaceous Ena Caldera, and older than granite batholiths associated with the Ena Caldera. The Ena-Agematsu Granite, the Himeguri Granite, and the Nohi Rhyolites are members of the Cretaceous Ena Caldera Complex. Ages of sedimentary rocks were determined by radiolarians, and granite by fission track dating of zircon.

Reported Minerals

• Ferrogedrite
• Ferro-actinolite
• Annite
• Almandine
• Galena
• Sphalerite
• Hawleyite
• Gahnite

Mineral Assemblages

• Almandine - Annite
• Ferro-actinolite - Sphalerite - Hawleyite
• Ferrogedrite - Quartz - Gahnite

History

• 1940-1945: Pb and Zn were mined during World War II.