Rock layers in the Grand Canyon.
The southwest region of the United States contains widely varying landforms, from the mile-deep Grand Canyon to multiple "fourteeners" -- mountains with an elevation greater than 14,000 feet. It is also home to large areas of sand dunes and natural bridge and arch formations. The U.S. Geological Survey defines the southwest region to include New Mexico, Arizona, Colorado, Utah and Nevada.
Colorado Plateau
The Colorado Plateau is an ancient region encompassing a 130,000 square mile area that includes parts of Arizona, New Mexico, Colorado and Utah. Geologists believe the Plateau is over 500 million years old; it remained stable while geologic upheavals created surrounding landforms, such as the Rocky Mountains. Though it is called a plateau, this region actually consists of a basin containing many plateaus. The Colorado Plateau contains many famous landforms, including the Grand Canyon and other canyons, Utah's Arches and Rainbow Bridge.
Grand Canyon
The Colorado River carved the Grand Canyon over a period of 5 to 6 million years, leaving a record of nearly half the earth's history through the layers of exposed rock in the canyon walls. Geological history aside, the size of the Canyon is awe-inspiring; it has an average width of 10 miles and an average depth of 4,000 feet along its 277-mile length. The Grand Canyon plunges down 6,000 feet at its deepest point.
Rocky Mountains
The Rocky Mountain range stretches from central New Mexico into Canada. It is composed of several subprovinces, with the subprovince of the Southern Rocky Mountains running through Colorado and New Mexico. Colorado contains the highest mountains in the range, including the second tallest mountain in the continental U.S., 14,433-foot Mount Elbert.
Sand Dunes
The Southwest contains two notable dune systems. The Great Sand Dunes in southern Colorado include the tallest dunes on the continent. Southern New Mexico's White Sands contains glistening white dunes due to the presence of gypsum sand. It is the largest gypsum dune field in the world at 275 square miles.
Tags: Grand Canyon, Colorado Plateau, Rocky Mountains, Colorado Utah, Mexico Colorado, million years, Sand Dunes
