Rio Grande Rift

The Rio Grande Rift is a north-trending continental rift zone running from central Colorado to Chihuahua, Mexico, separating the Colorado Plateau to the west from the interior of the North American craton to the east across four basins that average about 31 miles wide. It began forming roughly 35 million years ago through pure-shear extension, as the lithosphere stretched and pulled apart, drawing hot mantle material upward and driving the volcanism associated with the region today; geologists consider it the easternmost expression of the broad crustal extension that has affected the western United States over that same span. The Rio Grande river itself follows the rift's course from southern Colorado to El Paso before turning southeast toward the Gulf of Mexico, and the corridor has long served human settlement and travel, carrying major cities including Albuquerque, Santa Fe, Taos, Las Cruces, El Paso and Ciudad Juarez. This entity documents the Rio Grande Rift specifically as a geological formation, the rift structure itself, distinct from the Rio Grande river that flows along part of its course.