Capitol Reef National Park

Capitol Reef National Park


Geologic History

The Waterpocket Fold defines Capitol Reef National Park. A nearly 100-mile-long warp in the earth's crust, the fold is a classic monocline: a regional fold with one very steep side in an area of otherwise nearly horizontal rock layers. The Waterpocket Fold formed between 50 million and 70 million years ago when a major geologic shift in western North America reactivated an ancient buried fault. When the fault moved, the overlying rock layers were pushed up, bent and draped into the monocline. The fold is also known as Capitol Reef: "capitol" for the white domes of Navajo Sandstone that resemble rotundas, and "reef" for the rocky cliffs that are a barrier to travel, like an ocean reef.

Almost 10,000 feet of sedimentary strata are found in the Capitol Reef area. These rocks range in age from Permian to Cretaceous and this geologic layer cake records nearly 200 million years of history. Ancient environments revealed in the rock include rivers and swamps (Chinle and Moenkopi formations), Sahara-like deserts (Navajo and Wingate Sandstone) and shallow ocean (Mancos Shale). Cathedral Valley's freestanding monoliths are carved out of Entrada Sandstone, which was originally deposited as sandy mud on a tidal flat. Some of the cathedrals are capped by thin, hard beds of the Curtis Formation, a greenish-gray marine sandstone.

Most of the erosion that carved today's landscape occurred after the uplift of the Colorado Plateau some time within the last 20 million years. Water was the primary erosional agent; wind was a secondary influence. Today, both elements, plus the pull of gravity—in the form of rock falls or rock creep—continue to shape Capitol Reef's majestic domes, arches and canyons.

Human History

The "pockets" of the Waterpocket Fold are natural basins capable of holding thousands of gallons of rainwater. It was these water pockets and the water of the Fremont River and Sulphur Creek that attracted early human settlers. The Fremont Indian Culture began around A.D. 700. People lived here for about 600 years, farming, hunting game and gathering wild foods. Around A.D. 1300, they abandoned the area, perhaps because a prolonged drought made agriculture impossible. The Fremont people are known for their enigmatic rock writings. They left petroglyphs (carvings in rock) and -pictographs (paintings on rocks and stone walls) through-out the park. Their meaning remains a mystery.

Several hundred years passed before Capitol Reef saw any more permanent human habitation. In 1880, Mormon settlers established a community near the site of the present visitor center and campground. Using the water from the Fremont River for irrigation, they planted crops and orchards. They also grazed cattle. The pioneers lived here for less than 100 years; although President Franklin Roosevelt proclaimed the area a National Park Service national monument in 1937, the last residents left in 1969. Congress designated Capitol Reef a national park in 1971.

Still, the sandstone, limestone and shale stay on continuing to faithfully record the Earth's ever-changing environment.