Cold-water geyser

Cold-water geysers have eruptions similar to those of hot-water geysers, except that CO₂-bubbles drive the eruption instead of steam from the proximity to magma. In cold-water geysers, CO₂-laden water lies in a confined aquifer, in which water and CO₂ are trapped by less permeable overlying strata. This water and CO₂ can escape this strata only in weak regions like faults, joints, or drilled wells. A drilled borehole provides an escape for the pressurized water and CO₂ to reach the surface. The magnitude and frequency of such eruptions depend on various factors such as plumbing depth, CO₂ concentrations, aquifer yield etc. The column of water exerts enough pressure on the gaseous CO₂ so that it remains in the water in small bubbles. When the pressure decreases due to formation of a fissure, the CO₂ bubbles expand. This expansion displaces the water and causes the eruption. Cold-water geysers may look quite similar to their steam-driven counterparts; however, often CO₂-laden water is more white and frothy. The best known of these is probably Crystal Geyser, near Green River, Utah. There are also two cold-water geysers in Germany, named Wallender Born (a.k.a. Brubbel) and Andernach Geyser (a.k.a. Namedyer Sprudel); one in Slovakia, in the village of Herľany; and one in Brazil, in the municipality of Caxambu.

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