Most people in El Paso, if asked where they live, wouldn't dream of saying, "In the Rio Grande Rift". Furthermore, most would have no idea what that is. The Rio Grande from Colorado to El Paso follows a topographically low, elongate valley—the rift—formed by a major thinning of the region's crust. The west-central portion of the U.S. is being slowly pulled apart by processes similar to those that formed the Atlantic Ocean, resulting in El Paso sitting atop some of the thinnest continental crust in the world. In our area, the crust is only about 28 kilometers (around 17 miles) thick, in contrast to the 35 to 40 kilometers (22 to 25 miles) of most continental crust.
Convection of hot magma, upwelling liquid to semi-liquid rock that
diverges to the east and west as it meets the underside of the crust, may induce this
spreading, much as water brought to a boil breaks apart a layer of solidified grease
floating on top. In perhaps only a few million years, a new ocean basin may occupy this
area.
Contributor: Ethan Foster, Museum Studies Student, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.