Explore Geology
geology fieldnotes title

Capitol Reef

National Park

Utah

cover of park brochure

park geology subheading
Photo of Capitol Reef
Capitol Reef National Park, Utah

A giant, sinuous wrinkle in the Earth's crust stretches for 100 miles across south central Utah. This impressive buckling of rock, created by the same tremendous forces that built the Colorado Plateau 65 million years ago, is called the Waterpocket Fold. Capitol Reef National Park preserves the Fold and its spectacular, eroded jumble of colorful cliffs, massive domes, soaring spires, stark monoliths, twisting canyons, and graceful arches.

The Waterpocket Fold
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 Waterpocket Fold has lifted the rock layers on the west side 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 into the monocline.

As this artist's conceptual drawing shows, the Waterpocket Fold is made up of many layers of sedimentary rock.

Diagram of geology that created Capitol Reef
Drawing of the Fold as viewed looking South (East is to the left and West is to the right on this illustration).
These layers, which were originally horizontal, were formed from sediments deposited over hundreds of millions of years in seas, tidal flats, deserts, and other ancient environments. Then, as the uplift of the huge landmass of the Colorado Plateau began, the rock layers here were bent, or flexed, into a huge fold. Gradually, many of the uppermost layers of the ancient Fold (restored here) were completely eroded away, leaving only a hint of the enormity of the Waterpocket Fold in its earlier days. As wind and water continue slowly to erode the Fold, new features are created from the rock.

Capitol Reef
The most scenic portion of the Waterpocket Fold, found near the Fremont River, is known as Capitol Reef:

  • "capitol" for the white domes of Navajo Sandstone that resemble capitol building rotundas, and
  • "reef'' for the rocky cliffs which are a barrier to travel, like a coral reef.

Nearly 10,000 feet of sedimentary strata are found in the Capitol Reef area. These rocks range in age from Permian (as old as 270 million years old) to Cretaceous (as young as 80 million years old.) The Waterpocket Fold has tilted this geologic layer cake down to the east. The older rocks are found in the western part of the park, and the younger rocks are found near the east boundary.

This layer upon layer sequence of sedimentary rock records nearly 200 million years of geologic history. Rock layers in Capitol Reef reveal ancient climates as varied as:

  • rivers and swamps (Chinle Formation),
  • Sahara-like deserts (Navajo Sandstone),
  • and shallow ocean (Mancos Shale).

Cathedral Valley
The tilt of the Waterpocket Fold dies out at Thousand Lake Mountain near the northwestern boundary of the park. Rock layers in Cathedral Valley have a gentle inclination of 3 - 5 degrees to the east and appear nearly horizontal.

Deep erosion has carved Cathedral Valley's free-standing monoliths, or temples, out of the soft reddish-orange Entrada Sandstone, which was originally deposited as sandy mud on a tidal flat. Some of the cathedrals are capped by thin, hard beds of a greenish gray marine sandstone, the Curtis Formation.

The scenery of the Entrada Sandstone temples of Cathedral Valley is complemented by evidence of other geologic processes at work. Flowage and dissolution of gypsum, a soluble mineral from the underlying Carmel Formation, created Glass Mountain and the Gypsum Sinkhole. Glass Mountain is an exposed plug of gypsum. The Gypsum Sinkhole formed when a gypsum plug dissolved. Dikes and sills, which are thin bodies of igneous rock and small volcanic plugs, are found in Upper Cathedral Valley. These features formed during volcanic activity 3 to 6 million years ago.

Erosion
Most of the erosion that carved today's landscape occurred after the uplift of the Colorado Plateau sometime within the last 20 million years. Most of the major canyon cutting probably occurred between one and six million years ago.

Even in this desert climate, water is the erosional agent most responsible for the carving of the landscape. The pull of gravity, in the form of rock falls or rock creep, plays a major role in the shaping of the cliff lines. Wind is a minor agent of erosion here.

The landforms are a result of different responses of the various rock layers to the forces of erosion. Hard sandstone layers, like the red Wingate and the white Navajo Sandstones, form cliffs. Softer shale layers, like the Chinle Formation, form slopes and low hills. The barren slopes found in many areas are due in part to the presence of bentonitic clays in the shale which make an inhospitable environment for plants.

The black boulders, found scattered throughout the Fremont River valley and along other drainages, are recent geologic arrivals to Capitol Reef. These volcanic rocks came from the 20 to 30 million year old lava flows which cap Boulder and Thousand Lake Mountains. The boulders made their way to Capitol Reef during the Ice Ages when the High Plateaus supported small mountain glaciers. Landslides, debris flows, and possibly heavy stream outwash from these glaciers carried the boulders to lower elevations in the park.


Capitol Reef National Park was established because of the scenic rock domes and narrow canyons found along the trace of the Waterpocket Fold. Indeed, the park boundaries were drawn to geologic processes, and also to appreciate the interrelationships between the Earth and all life found in the varied environments within the park - from the forested slopes of Thousand Lake Mountain, to the green oasis of Fruita, to the barren Bentonite Hills.



park maps subheading

The General park map handed out at the visitor center is available on the park's map webpage.

For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.

photo album subheading

A photo album for this park can be found here.

For information on other photo collections featuring National Park geology, please see the Image Sources page.

books, videos, cds subheading

Currently, we do not have a listing for a park-specific geoscience book. The park's geology may be described in regional or state geology texts.

Please visit the Geology Books and Media webpage for additional sources such as text books, theme books, CD ROMs, and technical reports.

Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
ISBN 0-393-92407-6
9" x 10.75", paperback, 550 pages, full color throughout

The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!

Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.



geologic research subheading

Information about the park's research program is available on the park's research webpage.

For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.

The NPS maintains a searchable data base of research needs that have been identified by parks.

A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.



selected links subheading

NPS Geology and Soils Partners

NRCS logoAssociation of American State Geologists
NRCS logoGeological Society of America
NRCS logoNatural Resource Conservation Service - Soils
USGS logo U.S. Geological Survey

teacher feature subheading

Currently, we do not have a listing for any park-specific geology education programs or activities.

General information about the park's education and intrepretive programs is available on the park's education webpage.

For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.
updated on 01/04/2005  I   http://nature.nps.gov/geology/parks/care/index.cfm   I  Email: Webmaster
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