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The Colorado Plateau

The Vast and the Intimate
Suspended in Time
A Textbook of Geomorphology

Maps

Arizona
Colorado
New Mexico
Utah

Places

Aquarius Plateau, Utah
Arches NP, Utah
Arizona Strip
Black Mesa, Arizona
Canyon de Chelly, Arizona
Canyonlands NP, Utah
Chaco Canyon, New Mexico
Chuska Mountains, New Mexico
Dinosaur NM, Colorado/Utah
Glen Canyon/Lake Powell, Utah/Arizona
Grand Canyon, Arizona
Grand Canyon-Parashant NM, Arizona
Grand Staircase-Escalante, Utah
Upper Gunnison Basin, Colorado
Kaibab Plateau, Arizona
La Sal Mountains, Utah
Lees Ferry, Arizona
Little Colorado River, Arizona
Mesa Verde, Colorado
Mogollon Rim, Arizona
San Francisco Peaks, Arizona
White Mountains, Arizona
Wupatki/Sunset Crater, Arizona
Zion NP, Utah

PlacesThe Colorado Plateau Region (page 1 of 4)

Author: Ray Wheeler. Adapted from:  The Colorado Plateau Region, In Wilderness at the Edge: a citizen proposal to protect Utah's canyons and deserts, Utah Wilderness Coalition, Salt Lake City, 1990, p. 97-104.

coloplat.gif (88860 bytes)The Colorado Plateau is a physiographic "province," a region geologically and topographically distinct from other parts of the West. Originally named the "Colorado Plateaus" by explorer John Wesley Powell, the "Plateau" is in fact a huge basin ringed by highlands and filled with plateaus. Sprawling across southeastern Utah, northern Arizona, northwestern New Mexico, and western Colorado, the Colorado Plateau province covers a land area of 130,000 square miles. Of America's 50 states, only Alaska, Texas, California, and Montana are larger.

Natural hollow

This eighty foot-deep natural pocket is situated near the top of a 300-foot high Navajo Sandstone Dome in Grand Staircase-Escalante National Monument. It's floor is covered with bright orange sand deep enough to form 10 foot-high dunes, from which rises a 30 foot-high monolith of white sandstone.Photo 1985 Ray Wheeler.

Asked to explain what makes the Colorado Plateau unique, geographers grow cryptic, enigmatic, even mystical. Perhaps that is inevitable, for nothing is more typical of the "Plateau" than enigma itself. Geologically, it is perhaps best defined by what did not happen to it. While the Rocky Mountains to the east and the basin and range country to the west were being thrust, stretched, and fractured into existence, the Colorado Plateau earned a name for itself by the simple device of remaining structurally intact.

"The Colorado Plateau is extremely ancient," says author F.A. Barnes, an expert on the region's geology. "As a distinct mass of continental crust, it is at least 500 million years old -- probably a lot older." Such longevity is especially impressive when one considers the globetrotting adventures of the North American continent from the perspective of continental drift theory. Over a period of 300 to 400 million years, while the land mass that would become the North American continent inched northward from the South Pole, gradually disengaging itself from Africa, Asia, and South America, the Colorado Plateau region drifted along comfortably on its western edge. Now shoreline, now inundated by rising seas, the entire region accumulated huge quantities of sediment, gradually sinking under its own weight until heat and pressure hardened the deposits into a mantle of sedimentary rock several miles thick. Even when the entire western United States began to rise some 10 million years ago, eventually climbing to elevations as much as three miles above sea level, the Colorado Plateau region remained stable – perhaps "floating" on a cushion of molten rock.

Badlands

Mancos Shale badlands and Mt. Ellen in the proposed Henry Mountains Wilderness, southern Utah. Photo 1999 Ray Wheeler.

Though volcanic eruptions ring its perimeter, few have penetrated the interior of the Colorado Plateau. Blocked by massive layers of sedimentary rock, rising magma could do no more than bulge its thick roof into domes -- the "laccolithic" Henry, La Sal, and Abajo mountain ranges -- before cooling and hardening in place. The tremendous tectonic forces which formed the Sierra Nevada and Rocky Mountains had far less effect on the Colorado Plateau. Shielded or cushioned by something deep in the earth, the Plateau mirrored those forces but dimly -- as broad, dome-shaped uplifts, shallow basins, and long folds or "reefs." [Photos]

Follow these links to:
Vast—and Intimate
Suspended in Time
A Textbook of Geomorphology
References