Matsunaga Mine
Hongo, Tokigawa city, Hiki county, Saitama pref., Japan
Occurrence
Greenschist facies serpentinite
Talc schist and Tremolite schist in Sanbagawa Metamorphic Rocks. Formation of talc can be explained by the reaction of serpentinite with quartz in surrounding sedimentary rocks. The origin of this serpentinite block is considered as sedimentary serpentinite mélange from serpentinite seamounts at the fore-arc slope.
Outcrop of tremolite schist of Sanbagawa Metamorphic Rocks. Talc and tremolite were mined. This outcrop is mainly composed of dark gray to dark brown pelitic schist. The white bed at the left end is white tremolite-rich schist. The scale coin is at the boundary between tremolite schist and pelitic schist. Formation process of carbonate-absent talc schist can be explained by the reaction of serpentinite with quartz as follows:
Mg3Si2O5(OH)4 (Serpentine) + 4SiO2 >> Mg3Si4O10(OH)2 (Talc) + H2O
Reported Minerals
- Tremolite
- Talc
- Chlorite
- Stilpnomelane
Mineral Assemblages
- Quartz(Host) - Stilpnomelane
- Tremolite
- Talc
Localities
- Orihara (Talc, High-P)
- Matsunaga Mine (Talc, High-P)
- Shiraki (Pectolite, High-P)
- Arai (Diopside, High-P)
- Osaka (Ophicalcite, High-P)
- Miyazawa (Dolomite, High-P)
- Onara (Fe-Ni, High-P)
- Yashio mine (Fe-Cr, High-P)