Diversity of hydrothermal processes and different types of epithermal deposits

It is shown that classical epithermal deposits with hydrothermal explosions, brecciated and framework–lamellar (including agate-like) structures, and well-developed bonanzas are usually pre-porphyry in origin. This inference seems to be important for development of the genetic model of a porphyry–epithermal ore-forming system as well as for exploration of gold–silver deposits and assessment of their potential.