Monument Valley is a region of the Colorado Plateau characterized by a cluster of vast sandstone buttes, the largest reaching 1,000 ft (300 m) above the valley floor. It is located on the Arizona-Utah state line, near the Four Corners area. The valley lies within the range of the Navajo Nation Reservation and is accessible from U.S. Highway 163.
Monument Valley’s sculptures was created through patient and timeless erosion. During the Paleozoic Era (about 570 million years ago) the entire Colorado Plateau was underneath the Gulf of Mexico, which brushed against the young sediments of the Rocky Mountains. This inland sea withdrew further westward. The mountain chains began to rise along faults accompanied by basins. As the sea dried up, minerals were then buried by shorelines of sands and sediments washed down from the deltas. Materials that eroded from the Rocky Mountains were deposited over earlier layers and cemented into sandstones. An uplift generated by lava pressure from below the Earth’s crust caused the surface to bulge and crack. These cracks deepened and widened into rocky ravines and canyons.
The uplift of the young Colorado Plateau started to develop about 65 million years ago after the collision of the Pacific and North American tectonic plates off the coast of California, sending shock waves eastward. The natural forces still continue to the land today. The changes occur slowly with time through thousands of years unseen by the human eye. Endless erosion by water, wind and ice over millions of years chiseled rock formations into unique shapes of Monument Valley.