Geology of the Navajo Nation
The Navajo Nation lies entirely on the Colorado Plateau, and is made up of an array of geologic features including gentle uplifts, monoclines, broad basins, diatremes, and laccolith ranges (Baars, 1995 ).
The geologic setting of Navajo Country is made up of the Chuska Mountains and Defiance Uplift that separate the San Juan Basin and the Black Mesa-Holbrook Basin. The San Juan Basin is bounded on the east by monoclines and underlying basement faults of the Chama and Nacimiento-San Pedro Mountains, on the south by the Zuni Uplift, on the west by the Defiance Uplift, and to the north by the Hogback monocline and La Plata Mountains. West of the Defiance Uplift is the Black Mesa-Holbrook Basin complex, bounded on the south by the faulted escarpment of the Mogollon Rim, to the west by the Echo Cliffs and East Kaibab monoclines and to the north by the Comp Ridge monocline of the Monument Upwarp (Baars, 1995 ).
The geologic history of Navajo Country goes back more than 1.8 billion years. Precambrian basement rock is made up of mostly metamorphic rock with some igneous rock and underlies younger unmetamorphosed sedimentary rock. Paleozoic rocks are composed of thick layers of limestone, sandstone, siltstone, and shale that accumulated in shallow continental tropical seas. Mesozoic rocks were formed mostly by terrestrial deposits and are mainly sandstones with some shale (Geology of the Colorado Plateau (more info) ). Cenozoic rocks include igneous intrusions, diatremes and terrace gravels (Baars, 1995 ).
To further investigate the geology of the Navajo Nation, follow the links below.
Geology of the Colorado Plateau
Online resources containing information about the geology of the Colorado Plateau.
Geologic and Topographic Maps
Resources containing geologic and topographic maps on the Navajo Nation.
Suggestions for Future Reading about the Geology of the Colorado Plateau
Resources about the geology of the Colorado Plateau.