Saturday, July 3, 2010

The Wasatch Plateau

Although its official extent seems to vary among geographers, the Wasatch Plateau is a high ridge of horizontal Tertiary and late Mesozoic sediments that angles NNE to SSW through central Utah. To the north, it merges with the southwest end of the High Uinta Range and, to the south, it drops to the high tablelands of northern Arizona. The Plateau itself represents the divide between the Great Basin, to its west, and the Colorado Plateau, to its east; the Bear, Provo, San Pitch and Sevier Rivers drain to the west while the Strawberry, Price, San Rafael and Muddy Creek Rivers, destined to join the Colorado, drain to the east. At the south end of the uplift, the Virgin River flows southwestward, joining the Colorado at Lake Mead.

South of I-70, I-15 parallels the west edge of the Plateau down to St. George, Utah, while, north of I-70, a series of mountain ranges (the Pavant, San Pitch, Wasatch Front and Bear River Range, south to north) rise west of the Plateau. These ranges, representing the easternmost fault-block mountains of the Basin and Range Province, are separated from the Wasatch Plateau by a chain of valleys, quilted with horse and sheep ranches; Heber City, in the Provo River Valley, Mt. Pleasant, in the San Pitch Valley and the towns of the Sevier River Valley lie along this corridor.

Though the highest elevations of the Wasatch Plateau top out below 11,500 feet, it forms an imposing and rugged wall, covered with a rich forest of spruce, fir and aspen. Known for its high concentration of mule deer, the Plateau is also home to elk, black bear, mountain lions, coyotes and a host of smaller mammals. Zion and Bryce Canyon National Parks, among the most scenic locations in the United States, occupy the southernmost portion of this magnificent ridge.