Plateau - Major Plateaus of The World - Major Plateaus of North America

Major Plateaus of North America

In North America, the largest plateau is the Colorado Plateau covering an area of about 337,000 square kilometres (130,000 sq mi) in Colorado, Utah, Arizona and New Mexico.

The Colorado Plateau in northern Arizona and southern Utah is bisected by the valley of the Colorado River and the Grand Canyon. How this came to be is that over 10 million years ago, a river was already there, though not necessarily on exactly the same course. Then, subterranean geological forces caused the land in that part of North America to gradually rise by about a centimeter per year for millions of years. An unusual balance occurred: the river that would become the Colorado River was able to erode into the crust of the Earth at a nearly equal rate to the uplift of the plateau. Now, millions of years later, the North Rim of the Grand Canyon is at an elevation of about 2450 meters (9800 ft) above sea level, and the South Rim of the Grand Canyon is about 2150 meters (8200 ft) above sea level. At its deepest, the Colorado River is about 1830 meters (6000 ft) below the level of the North Rim.

The southern edge of the plateau in northern Arizona is called the Mogollon Rim, where the elevation of the land declines steeply into central Arizona. This Mogollon Rim is located about 20 kilometers south Flagstaff, Holbrook, Winslow, and Williams, Arizona. Because of the snowy plateau and the San Francisco Mountains to its north, the Mogollon Rim area is noted for its many natural springs and artesian wells.