Abukuma Cave
Oguno, Hinode city, Nishitama county, metropolis, Japan
Occurrence
Stalactite cave formed by deposition of CaCO3 dissolved from limestone of the Early Jurassic (180 Ma) Ohirayama unit, a member of the Southern Chichibu accretionary complex. Ohirayama unit has been subjected to weak Prehnite-Pumpellyite to Zeolite facies metamorphism as a low grade part of the Sambagawa metamorphic belt in the Late Cretaceous (100 Ma). The age of limestone is Permian to Triassic (298 - 201 Ma). Ages of sedimentary rocks were determined by radiolarians, and metamorphic age by K-Ar or Ar-Ar radiometric dating of muscovite.
Stalactite deposited on open spaces in limestone, CaCO3 was dissolved by underwater from limestone, and it deposited as stalactite. Stalactite is mainly composed of aragonite. There are coral fossils on the surface of the host limestone.
Reported Minerals
- Aragonite
- Calcite
Mineral Assemblages
- Calcite - Aragonite
Localities
- Abukuma Cave
- Gyokusen Cave
- Otake Cave
Related Occurrences
- Stalactite
- Tufa (Calcareous sinter)
- Travertine (Calcareous sinter)