Arizona, United States
Navajo Mountain, in southeastern Utah and adjacent Arizona, is a prominent free-standing laccolith, a dome-shaped body of igneous rock that intruded into sedimentary layers and lifted up the overlying layer. The igneous rock at the core of the mountain is wrapped in sedimentary layers. Such igneous intrusions have been exposed by erosion and well studied in similar mountain ranges on the Colorado Plateau, such as the Henry Mountains, the Abajo Mountains, and the La Sal Range.
The Colorado Plateau is made of mostly flat-lying layers of sedimentary rock that record paleoclimate extremes ranging from oceans to widespread deserts over the last 1.8 billion years. The peak of Navajo Mountain, at approximately 10388 feet, is made up of uplifted Dakota Sandstone deposited during the Cretaceous Period (approximately 66-138 million years ago).
The Navajo Mountain region has special cultural significance to the Navajo people, who know it as Naatsis’áán ("Earth Head" or "Pollen Mountain"). Together with Rainbow Bridge to the northwest, Navajo Mountain figures prominently as the first settlement area in western Navajo origin stories. Following the military defeat of the Diné (Navajo) by United States forces in 1863, the political landscape was changed by new boundaries and major physical alterations. The establishment of Rainbow Bridge National Monument (1910), and the filling of Glen Canyon by Lake Powell in 1963, has facilitated tourism of this previously remote region. Access to Navajo Mountain is still regulated by the sovereign Navajo Nation, and a permit is required to hike in the region.