Hydrothermal Deposit along Fault
Chemical Process (Liquid-phase Growth) - Open system under ground
Required Geological Setting
Associated metasomatic zones
Cristobalite zone, Smectite zone
Occurrence
Deposit formed along large scale faults by hydrothermal fluid less than 50 degree. Origin of hydrothermal fluid is meteoric water, and/or seawater. This type of deposits is formed along faults whereas Hot spring deposit is formed at shallow circumstances by the same hydrothermal fluid less than 50 degree. Minerals deposited depend on characteristics of hydrothermal fluid reflecting geological settings of faults. Host of deposits are hosts of faults and fault gauge. It is considered that the deposit may shift to cataclasite or mylonite in the deeper level in some cases.
Distribution of hydrothermal deposits along faults described in this site. Yellow lines are large scale faults recognized as tectonic lines.
Mineral Assemblages (Acidic)
Chalcedony
Mineral Assemblages (Neutral)
Calcite
Mineral Assemblages (Alkaline)
Dolomite, Siderite, Dawsonite
Localities
- Ichino River (Fault, Chalcedony)
- Tatarazawa (Median Tectonic Line, Dawsonite)
- Niu (Median Tectonic Line, Dawsonite)
- Hitodo (Kannawa Fault, Glauconite)