Groundwater deposition
Chemical Process (Liquid-phase Growth) - Open system under ground
Occurrence
Minerals deposited from groundwater. Components of minerals are solved in groundwater through diagenesis and are transported by groundwater to the deposition sites. As the process is strongly associated with groundwater, the shape of deposits is tabular parallel to the water table in high permiability beds such as conglometates and sandstones. Minerals also deposit in fissures near the ground surface. Mineral assemblages depend on the surrounding rocks; quartz and opal near such SiO2-rich rocks as sandstones, calcite near fossil shell beds, limonite near mafic rocks, manganese dioxides near Mn-rich cherts and volcanic rocks.
Distribution of minerals deposited from groundwater. Yellow zones indicate the distribution of Quaternrary, Neogene, Paleogene sediments and accretionary complexes.
Mineral Assemblages
Opal, Quartz, Calcite, Gypsum, Limonite, Manganese dioxides
Localities
- Shimo-jinya (Conglomerate, Lithiophorite)
- Mount Orihime (Chert, Lithiophorite)
- Masaka (Chert, Lithiophorite)
- Umoona Mine (Opal deposit)
- Old Timers Mine (Gypsum, Fibrous)
- Opal Quest Mine(Gypsum, Rosette)
- Moon plain (Gypsum, Tabular)
- Jweller's shop noodling area (Chalcedony)