Simulating the Conditions of Generation for Permeable Geyser Channels in Areas of Acid Volcanism

The geysers and paleo-geysers that exist in Kamchatka are situated in volcanogenic artesian basins composed of products of recent acid volcanism. This is in accord with the worldwide patterns for the occurrence of geyser fields. The results of a TOUGHREACT simulation of flow-through ascending circulation of thermal waters, which have chemical compositions in agreement with that of the water in Geyser Valley and which occurs in rhyolite host rocks, showed the generation of channels with high transmitting capacity and lateral self-isolation. This occurs due to the high rate of dissolution for volcanic glass in an axial ascending flow and deposition of silica in the annulus. Studies of mineral composition, as sampled at the surface of cones/gryphons at the Velikan, Bolshoi, and Pervenets geysers, showed them to be dominated by the zeolite mineral phase (heulandite, clinoptilolite, and mordenite) with some minor amounts of amorphous silica (opal).