Physico-chemical properties of hydrothermal fluids

Fluids drive geologic processes. Among common geologic materials, hot water is unquestionably one of the most assertive, dynamic and changeable in terms of how it dominates chemical reactions between minerals, moves other substances around, and leaves a diverse record of effects in rocks. These phenomena largely reflect the incredible diversity of physico-chemical properties of hydrothermal fluids, which in turn reflect wide variations in pressure, temperature and chemical composition. The objective of this review is to outline how and why these variations allow hydrothermal fluids to take on so many different flavors, and to affect geologic processes in such diverse and potent ways.