Wilson Cliffs Thrust
March 30, 2007
The contact between the gray Cambrian (~ 500 million years old) Bonanza King Formation carbonates, at left, and the yellow and red Jurassic (~170 million years old) Aztec Sandstone, at right, is known as the Wilson Cliffs Thrust Fault. It's found in Red Rock Canyon National Conservation Area, just west of Las Vegas, Nevada. As part of the world famous Keystone Thrust system, the Wilson Cliffs Thrust formed due to compression of what's now the western U.S. This compression fractured the crust and pushed the older Cambrian carbonates eastward on top of the younger Jurassic sandstone during the Sevier Orogeny (~ 70 million years ago). In this photo, the sandstone beds are slightly upturned near the fault contact. This occurred when the eastward (to the right in this image) thrusting fault caught on the sandstone and pulled it along with the upper plate of carbonates. See also the Earth Science Picture of the Day for September 27, 2006.