f The alternation haloes as the main target of epithermal gold exploration

Gold of economic grade in fossil hydrothermal system has emerged as one of the recent challenges in metallogeny. The main target of epithermal gold exploration are the products of past geothermal activity, According to V. Lindgren and V.A. Obruchev alteration haloes caused by the hydrothermal fluid are relic on the surface of the burried fossil hydrothermal system.