Geologic map of Arches National Park and vicinity, Grand County, Utah (M-74)

By: H. H. Doelling

Arches National Park has an unique variety of well-exposed and colorful rock formations. It is located in the Paradox Basin of the Colorado Plateau Physiographic Province which lies in parts of four western states: Utah, Colorado, Arizona, and New Mexico. The Paradox Basin straddles the Utah-Colorado State line in the north central part of the physiographic province and is an area in which thick beds of rock salt were deposited some 300 million years ago. This salt is older than the rocks exposed in the park.

Rock salt has many unique properties. Unlike other rock materials, for example, it is both plastic and soluble. These properties have greatly influenced the subsequent geologic history of the area, especially in the deep part of the basin in which Arches National Park is found. This area is characterized by northwest-trending salt anticlines which appear at the surface as valleys bounded by escarpments or cliffs. Examples of such valleys include Salt Valley and Cache Valley inside the park and the valley in which the town of Moab is found. The arches and fins of the national park are mostly located on the cliffs adjacent to Salt Valley and Cache Valley. These, and the other landforms of the area, are mostly reflections of the effect of subterranean salt flowage and dissolution on the surface rocks. Arches National Park has the greatest concentration of natural rock arches in the world, but this would not have been possible without the presence of salt.

Other Information:
Published: 1985
Pages: 15 p.
Plates: 1 pl.
Scale: 1:24,000
Location: Grand County
Media Type: Paper Map - Rolled or folded, Polypropylene Rolled or Folded