2005 Capitol Reef National Park, UT

The Waterpocket Fold defines Capitol Reef National Park. A nearly 100-mile long warp in the Earth's crust, the Waterpocket Fold is a classic monocline: a regional fold with one very steep side in an area of otherwise nearly horizontal layers. A monocline is a step-up in the rock layers. The rock layers on the west side of the Waterpocket Fold have been lifted more than 7000 feet higher than the layers on the east. Major folds are almost always associated with underlying faults. The Waterpocket Fold formed between 50 and 70 million years ago when a major mountain building event in western North America, the Laramide Orogeny, reactivated an ancient buried fault. When the fault moved, the overlying rock layers were draped above the fault and formed a monocline.

More recent uplift of the entire Colorado Plateau and the resulting erosion has exposed this fold at the surface only within the last 15 to 20 million years. The name Waterpocket Fold reflects this ongoing erosion of the rock layers. Waterpockets are basins that form in many of the sandstone layers as they are eroded by water. These basins are common throughout the fold, thus giving it the name Waterpocket Fold. Erosion of the tilted rock layers continues today forming colorful cliffs, massive domes, soaring spires, stark monoliths, twisting canyons, and graceful arches.