UNIQUE GEOLOGIC CHARACTERISTICS OF “THE WAVE” IN JURASSIC NAVAJO SANDSTONE, VERMILION CLIFFS NATIONAL MONUMENT, ARIZONA

“The Wave” in the Jurassic Navajo Sandstone at Coyote Buttes, lies at the northern margin of the Vermilion Cliffs National Monument on the Arizona and Utah border. This feature, named for its resemblance to a cresting ocean wave, is a tremendous draw for thousands of wilderness enthusiasts and photographers every year. There are three major geologic features that contribute to the unique character of The Wave.

1. Large eolian foresets consist of rhythmic and cyclic alternating grainflow and windripple laminae that reflect seasonal changes in dune migration.

2. Stunning sandstone coloration in a wide range of red, orange, yellow, white, and purple hues is largely controlled by iron oxide mineralogies that document diagenetic fluid flow and chemical reaction fronts in Navajo Sandstone. There are at least four distinct coloration events: an initial reddening by syndepositional to early diagenetic grain-coatings of iron oxides (e.g., hematite); a bleaching event by reducing fluids; a secondary introduction of Fe evidenced by dark, black to purple liesegang rings; and a final overprinting of a yellow liesegang-type banding.

3. Although The Wave follows a large natural fracture in an upper cliff of the Navajo Sandstone that has been enlarged by water, the smooth bowl is a predominantly wind-scoured channel with its dimensions likely acting as a venturi, to effectively increase wind speed within the bowl of The Wave. Wind erosion further sculpts around delicate eolian foreset features to enhance textural differences and highlight the diagenetic colors.

The Wave's combination of features provides insight into the geomorphic and diagenetic evolution of eolian deposits on the Colorado Plateau. The Wave is a valuable geologic resource for the scientific community, and an exceptional aesthetic landscape feature for resource management in the Vermilion Cliffs National Monument.