Figures and pictures used with permission from
"Windows into the Earth, The Geologic Story of
Yellowstone and Grand Teton National Park", Robert B.
Smith and Lee J. Siegel, Oxford University Press,
2000.
Figure 4. Workings of
Yellowstone geyser illustrate how heat from cooling magma
rises to warm dense salty water circulating in a porous
rock later. The brine transfers heat to overlying fresh
groundwater, which is recharged by rainfall and snowmelt.
The shallow hot water can be trapped and pressurized in
small underground reservoirs, then released suddenly
through narrow openings, creating geysers.
