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Yellowstone Rock: Made by Volcanic Hot Springs

by | Apr 26, 2024

Not too far below the ground, the Yellowstone supervolcano’s persistent geothermal heat stokes iconic geysers, boiling mudpots, and colorful hot springs. A body of magma resides about 3 miles below the surface of Yellowstone National Park. The hot rock warms the groundwater, which then travels upward along faults, dissolving minerals from the surrounding rock as it passes by. By the time the hot water emerges at the surface, it’s laden with minerals. Travertine is the most common type of stone made by hot springs. Calcium carbonate is dissolved from layers of limestone rock below and carried upward. As the water flows out of the earth, it cools down and deposits the minerals. Over time, the flowing hot water leaves behind layer upon layer of newly-formed rock in the artistic pattern that makes travertine so treasured.