Geologic Tour of the Colorado Plateau

northwestern New Mexico
Figure 1. Map showing state parks, federal facilities, and geologic features in northwestern New Mexico. Click on localities of interest for more information.

Brief Description

The Colorado Plateau in the northwestern corner of New Mexico is part of a larger geologic feature of the same name that also covers portions of northeastern Arizona, southeastern Utah, and southwestern Colorado (Figure 2). The Colorado Plateau of the Four Corners region is on average 2.1 km (1.3 miles) above sea level. The Colorado Plateau is characterized by relatively flat-lying, red, white, gray, green, and yellow sedimentary rocks that have been sculpted into mesas, buttes, and badlands over the eons by the erosive effects of water (Figures 3 and 4).

The Colorado Plateau in New Mexico includes the San Juan Basin, a major source of oil, gas, coal, and uranium for our state. The northwest-trending Zuni Mountains form the southwestern margin of the San Juan Basin. Both the San Juan Basin and the Zuni Mountains are broad downwarps and upwarps that formed during regional-scale compression about 75 million years ago during the Laramide orogeny (e.g., Cather, 2004). The southeast margin of the Colorado Plateau is covered by <5 million volcanic rocks that erupted along the Jemez lineament, a northeast-trending zone of weakness that likely developed about 1.6 billion years ago as the North American continent was forming.

 

colorado plateau map
Figure 2. Map of the Colorado Plateau in the Four Corners region with respect to the volcanic centers of the Jemez lineament (red) and the Rio Grande rift (yellow).
mesa alta escarpment
Figure 3. Gently warped Triassic to Cretaceous sedimentary rocks on Mesa Alta in the eastern part of the Colorado Plateau of New Mexico. Photograph by Shari Kelley.
butte
Figure 4. Paleocene and Eocene shale and sandstone in the San Juan Basin of New Mexico. Photograph by Richard Kelley.

References

  1. Cather, S.M., 2004, The Laramide orogeny in central and northern New Mexico and southern Colorado, in Mack, G.H., and Giles, K.A., eds., The Geology of New Mexico, A Geologic History: New Mexico Geological Society Special Publication 11, p. 203-248.