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.
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.
The variety of the region extends to its life as well as its geology. Animals and plants have adapted to the exposed rock strata and harsh climatic conditions. Separated by chasms, clinging to shelves of exposed rock, or making their living in roaring rivers, they evolved into unique species like the Colorado squawfish, a minnow that can reach nearly six feet in length.
The Colorado Plateau province can be divided into six sections. The highest of these is the High Plateaus of Utah, featuring great rock cliffs and terraces ascending