Geology of the Navajo Nation

This page was written by Erin Klauk as part of the DLESE Community Services Project: Integrating Research in Education.

Triassic, Jurassic, and Tertiary rocks exposed along the western flank of the Lukachukai Mountains in the north central Navajo Nation. Details

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 ).

Lower Jurassic Navajo Sandstone exposed in the Comb Ridge monocline east of Kayenta, Navajo Nation, Arizona. Details

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.

For ideas on how to use these webpages in a classroom, a Study Guide is provided.