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Yellowstone National Park
How Geysers Work
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For geyser to occur there must be heat, water, and a plumbing system. A magma chamber provides the heat, which radiates into surrounding rock. Water from rain and snow works its way underground through fractures in the rock.
As the water reaches hot rock it begins to rise back to the surface, passing through rhyolite, which is former volcanic ash or lava rich in silica. The hot water dissolves the silica and carries it upward to line rock crevices. This forms a constriction that holds in the mounting pressure, creating a geyser's plumbing system.
As superheated water nears the surface, its pressure drops, and the water flashes into steam as a geyser. Hot springs have unconstricted plumbing systems.
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![Dog Hooked to Travois for Transporting Goods. Dog Hooked to Travois for Transporting Goods.](https://webarchive.library.unt.edu/eot2008/20081014075951im_/http://www.nps.gov/imr/customcf/apps/CMS_HandF/Pictures/YELL_dogtravois.jpg) |
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Did You Know?
Some groups of Shoshone Indians, who adapted to a mountain existence, chose not to acquire the horse. These included the Sheep Eaters, or Tukudika, who used dogs to transport food, hides, and other provisions. The Sheep Eaters lived in many locations in Yellowstone.
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Last Updated: July 20, 2006 at 19:30 EST |