Keystone Thrust and Spring Mountains, Nevada.

Flying into Las Vegas from the west, you go right over the Keystone Thrust --shown here as the contact between the gray and tan-colored rock. The gray rock consists of Cambrian-age Bonanza King Formation, a limestone, and the tan rock consists of the Jurassic Aztec Sandtone --the same rock as the Navajo Sandstone in Utah. So... older rock faulted over younger rock... a thrust! But the Keystone Thrust isn't just any thrust fault--it's the frontal thrust in the Cordilleran Fold and Thrust Belt, which goes from here all the way to the Brooks Range of Alaska!

The sandstone cliffs make up Red Rock Canyon, one of Nevada's state parks and a popular climbing area.


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