GEOLOGY OF THE COLORADO PLATEAU

Abstract

Introduction The Colorado Plateau is a land of scenic beauty characterized by sparsely vegetated plateaus, mesas, deep canyons, and barren badlands. It encompasses an area of approximately 140,000 square miles in the four corners region of Utah, Colorado, Arizona and New Mexico. It includes the area drained by the Colorado River and it's tributaries the Green, San Juan and Little Colorado Rivers (figure 1). The combination of high relief and an arid climate over most of the plateau has resulted in limited plant cover. The products of weathering are easily eroded by fast moving streams leaving behind bare rocks which produce the dramatic scenery of this area. Not to mention, the excellent rock exposures waiting to be explored by a group of geology students. Elevations on the plateau range from 3,000 to 14,000 feet with an average of 5,200 feet. Due to the high range in elevations, the climate ranges from Sonoran desert to Alpine, however, semiarid conditions prevail. The high Sierra Nevada mountains of the West Coast prevent Pacific, moisture laden air masses from reaching the southwestern states. As a result of this rain shadow effect, annual precipitation on the Colorado Plateau is low, averaging about 10 inches per year.