Origins of the Solutions Magmatic Sources Meteoric water

Origins of the Solutions • Magmatic Sources • Meteoric water (ground water) sources • Seawater sources • Regional Metamorphism !

hydrothermal system

Composition of the Solutions • The principle ingredient of hydrothermal solutions is a brine – hot water • Containing dissolved salts such as Na. Cl, KCl, Ca. SO 4 and Ca. Cl 2 • The range in salinity varies from that of seawater to about ten times the salinity of seawater • Capable of dissolving small amounts of elements such as Au, Ag, Cu, Pb and Zn • High temperatures increase the effectiveness of the brines to dissolve metals

Causes of Mineral Precipitation • a convection cell is required to maintain a constant precipitation • Rapid movement of the fluid into porous layers (open fractures such as veins and brecciated rocks) • Sudden cooling of the fluids leads to rapid precipitation of minerals over a limited region • Boiling, rapid pressure decrease, reactions with adjacent rock types, and mixing with seawater can also cause rapid precipitation and the concentration of mineral deposits.