The immense, topographically complex chasm that we know as the Grand Canyon of the Colorado River began its evolution billions of years ago. It began to form not through dramatic geologic tumult, as its modern form might suggest, but very gently, as ancient seas built shorelines layer upon layer through the slow yet inexorable deposition of eroded sediment. Roughly 75 million years ago the internal furnace of the planet caused tectonic collisions and buckling that uplifted the mountains and plateaus of what would become western North America, including those layers of ancient shorelines that would form the base of the Colorado Plateau. Tectonic forces lifted the sedimentary and other rock of the Colorado Plateau thousands of feet above sea level, yet that uplift thrust the Rocky Mountains, to the east and north of the Colorado Plateau, nearly a mile higher.
Weatherwise contributing editor ED DARACK is an independent author and photographer who covers a broad range of topics. His next book is The Final Flight of Extortion 17, published by Smithsonian Books. Learn more at www.darack.com.