Unique Geology

View item information

View of the Mittens rock formations in Monument Valley, 1950s. Courtesy of the Utah State Historical Society via Mountain West Digital Library.

The Mountain West is divided into three distinct geological regions: the Rocky Mountains, the Colorado Plateau, and the Great Basin, each with its own unique attributes. The area was created through intense volcanic and uplift activity whereby the mountains were pushed violently through the surrounding layers of the Earth’s crust. Volcanic activity still exists in the area of Yellowstone National Park, which is a “supervolcano” that could cause eruptions thousand times those of a typical volcano. It is consistently monitored for seismic activity.

The area went through many changes during the ice ages when glaciers carved the landscape. Large ice sheets covered some portions of land and dammed up rivers in others, creating glacial lakes. Many lakes, including Lake Bonneville and the Great Salt Lake, are remnants of the ancient freshwater lake that covered most of the eastern Great Basin. The eastern Mountain West is covered by plateaus and basins where natural resources like minerals, oil, oil shale, and natural gas abound as remnants of the geologic past. Much of the southern and southeastern landscape cuts through layers of sandstone, displaying many colors and shapes developed through years of wind and water erosion. Much of this landscape is part of protected national parks such as Arches, Bryce Canyon, Canyonlands, Capitol Reef, and Zion, state parks such as Goblin Valley and Monument Valley, and national monuments like Dinosaur National Monument.