Yanda
Hama, Kawazu city, Kamo county, Shizuoka pref., Japan
Synonym
Hiraiso, Hiraiso Seashore
Occurrence
Alkaline metasomatic rocks of Heulandite-Analcime zone
Vesicules of the andesitic to basaltic tuff breccia of the upper part of the early Pliocene (4.0 Ma) Shirahama Group. Tuff breccia is a part of pillow lava and hyaloclastite. Andesite and basalt of the upper Shirahama Group are tholeiitic, and have been subjected to propylitization alteration. The Shirahama Group unconformably overlies the Miocene Yugashima Group. Ages of sediments were determined by microfossils and K-Ar radiometric dating.
Outcrop of tuff breccia of the Shirahama Group. The outcrop consists of tilted alternating beds comosed of larger fragments and smaller fragments. The beds of larger fragments are composed of brecciated pillow lava, and the beds of smaller fragments are hyaloclastite. It turned greenish by propylitization alteration.
Reported Minerals
- Heulandite-Ca
- Mordenite
- Dachiardite-Ca
- Apophyllite-(KF)
- Stilbite-Ca
- Thomsonite-Ca
- Calcite(Pyramidal)
- Chalcedony
Mineral Assemblages
- Heulandite-Ca - Mordenite
- Dachiardite-Ca
- Chalcedony
Localities
Related Occurrences
- Halloysite zone (Alunite zone, Argillized zone)
- Kaolinite zone (Alunite zone, Argillized zone)
- Minamiite-Alunite zone (Alunite zone)
- Pyrophyllite zone
- Smectite zone (Argillized zone)
- Interstratified mineral zone (Argillized zone)
- Illite-Chlorite zone (Propylite zone)
- Epidote-Actinolite zone
- Stilbite-Mordenite zone (Zeolite zone)
- Heulandite-Analcime zone (Zeolite zone)
- Laumontite-Albite zone (Zeolite z., Propylite z.)
- Wairakite-Albite zone (Zeolite zone)