Saruhashi Mine
Saruhachi, Otsuki city, Yamanashi pref., Japan
Synonym
Shindo Mine
Occurrence
Iron sandstone in the middle Miocene (15 Ma) Ozawa Member of the Otsuki Formation, the Tsuru Group. The Ozawa Member is the bottom member of the Otsuki Formation, and unconformably overlies the Akiyama Formation of the Tsuru Group. The Ozawa Member is conformably underlies the Saruhashi member of the Tsuru Group. The Saruhashi Member is considered as sendiments in a brackish fan delta near the andesite-dacite submarine volcano. This Ozawa Member has been known as the Pliocene Furuya Formation of the Nishikatsura Group or the Saruhashi Formation, the Saruhashi Member as the Pliocene Katsura Formation of the Nishikatsura Group or the Iwadonosan Formation. Classification may be changed in future.
Outcrop of iron sandstone or magnetite sandstone of the Ozawa Member, Otsuki Formation. The two beds protruded are sandstone composed of magnetite and minor calcite. The notched beds at the left and between iron sandstone beds are conglomerate whose matrix is magnetite. Pebbles are rounded very well. The left side of this photograph is the higher stratigraphic level. There is a bed of conglomerate including Ostrea fossils (Ostrea sp.) at the upper level of this iron sandstone. The scale coin is slightly below the center.
Reported Minerals
- Magnetite
- Ferrosaponite
- Calcite
Mineral Assemblages
- Magnetite - Ferrosaponite - Calcite
History
- 1937: Mr. Yoshiro Katsuta found the deposit.
- 1939 - 1945: 2,000 ton ore was mined.
- 1954: The mine was closed.
Localities
- Saruhashi Mine (Tertiary, Iron sandstone)
- Fuji Mine (Tertiary, Iron sandstone)
- Daido Mine (Iron sandstone)