The grandeur of Grand Canyon lies not only in its size, but also in the beauty of its landscape. In this respect, Grand Canyon shares many characteristics with its neighbors—Zion, Bryce, Canyonlands, Arches, and Capitol Reef national parks. Like Grand Canyon, these neighboring parks lie within the geologic province known as the Colorado Plateau (see below), a region characterized by mostly flat-lying sedimentary rocks that have been raised thousands of feet above sea level, then carved by erosion.
Precambrian Basement Rocks
The basement rock formed 1.8 billion years ago when the North American continent collided with an ancient chain of volcanic islands, much like today’s Hawaiian Islands. Intense heat and pressure from the collision formed rock called Vishnu Schist. From deep under the earth’s surface, molten rock flowed up as magma between the cracks of the Vishnu Schist. As the flowing magma cooled and hardened, it formed veins of pinkish rock called Zoroaster Granite. Because of the extreme heat and pressure that folded and changed the rock, any fossils in the original rock were destroyed.
Bright Angel Shale
If you came to Grand Canyon area 515 million years ago when the Bright Angel Shale was forming, everything was covered by a very muddy, warm, shallow sea. Trilobites, brachiopods, crinoids and worm-like creatures that burrowed in the sea-floor thrived in the nutrient-rich water. This greenish-colored shale forms the broad, flat area known as the Tonto Platform in Grand Canyon.
Are you ready to go wading through the mud? About 280 million years ago the Grand Canyon area was covered by a broad coastal plain that had many slowly meandering streams. The environment was excellent habitat for an abundance of ferns and conifers, along with reptiles and insects, including dragonflies with 12-inch wingspans. This layer consists of siltstones, mudstones, and fine grained sandstones rich in iron that create a gentle, red slope in most parts of Grand Canyon National Park.
Have you ever wanted to visit the Sahara desert? About 275 million years ago the Grand Canyon area was covered with large dune-fields. The ocean lay to the west. Reptiles, spiders, scorpions, and other insects dwelled on the sand dunes of this extensive desert, leaving their tracks fossilized in the sandstone. This sandstone layer creates a broad, light-colored cliff a few hundred feet below the rim of Grand Canyon. Cross-bedding (lines that run at steep angles to oneanother) can be seen in the rock, giving evidence to the wind-blown sand dunes that once covered the area.
About 270 million years ago North America was the western part of the super-continent Pangaea. The Grand Canyon region was once again covered by a shallow, warm, and well-lit clear sea with a sandy/muddy floor. Brachiopods, sponges, and other sea creatures dominated these waters. Other species included crinoids, corals, bryozoans, cephalopods, sharks and fish. This limestone is the youngest, and therefore the topmost, rock layer found at Grand Canyon National Park.
There is a gap in the rock record between Cambrian times and pre-Cambrian, 550 million years ago. An unconformity is a surface in the rock record in a stratigraphic column representing a time from which no rocks were preserved or formed, or when rocks were formed buy eroded away.
Small unconformities are ubiquitous in the rock record. But the Great Unconformity is important because it represents a long period of time (250-1200 million years in the Grand Canyon), and it is found nearly everywhere in the world.
And it divides rocks with familiar fossils from those with no fossils or only fossil bacteria.
Below, you will find the Great Unconformity at the bottom of the blue layer.
The Grand Staircase is an immense sequence of sedimentary rock layers that stretch south from Bryce Canyon National Park through Zion National Park and into the Grand Canyon. In the 1870s, geologist Clarence Dutton first conceptualized this region as a huge stairway ascending out of the bottom of the Grand Canyon northward with the cliff edge of each layer forming giant steps. Dutton divided this layer cake of Earth history into five steps that he colorfully named Pink Cliffs, Grey Cliffs, White Cliffs, Vermilion Cliffs, and Chocolate Cliffs. Since then, modern geologists have further divided Dutton's steps into individual rock formations.
What makes the Grand Staircase worldly unique is that it preserves more Earth history than any other place on Earth. Geologists often liken the study of sedimentary rock layers to reading a history book--layer by layer, detailed chapter by detailed chapter. The problem is that in most places in the world, the book has been severely damaged by the rise and fall of mountains, the scouring of glaciers, etc. Usually these chapters are completely disarticulated from each other and often whole pages are just missing. Yet the Grand Staircase and the lower cliffs that comprise the Grand Canyon remain largely intact speaking to over 600 million years of continuous Earth history with only a few paragraphs missing here and there.
Unfortunately, the Grand Staircase is such a vast region of rock that no matter where you stand on its expanse, most of it will be hidden behind the curvature of Earth. Places such as Yovimpa Point and the north slope of the Kaibab Plateau are the exception where even a non-geologist can discern the individual chapters of this colossal history book--these immense steps of Dutton's Grand Staircase.
Illustration at top of page shows how the layers that form the steps.
I've always considered myself a mountain girl. But the more I have traveled in the Colorado Plateau, the more it has crept into my soul.
The Colorado Plateau, a landscape of levels, is a physiographic province encompassing 130,000 square miles of the Four Corners states, including Utah's southeastern quarter. There are 25 geographic provinces in the U.S., and arguably, it is the least-tamed country remaining in the lower forty-eight states.
The name is deceptive. Originally named by John Wesley Powell, it is not a single plateau but comprises of a series of tablelands where stream valleys are typically narrow and widely spaced, dissecting the region until it forms into the grandest valley.
Named for the Colorado River, it extends across the southwest covering the southeastern half of Utah, extreme western and southwestern Colorado, northwestern New Mexico, and the northern half of Arizona. Its size about 130,000 square miles. The plateau is dominated by high mountains that are gashed by river canyons or scarred with dry gullies and washes and the beds of intermittent streams Often waterless). Elevations range from 2,000 feet (600 m) in the Grand Canyon to more than 12,700 feet (3,870 m) in the La Sal Mountains near Moab. Erosion by the Colorado River system has carved deep, brilliantly colored gorges, most notably the Grand Canyon. About 90% of the area is drained by the Colorado River and its main tributaries: the Green, San Juan, and Little Colorado. And it is home to many Indian reservations. The Ancestral people lived in the region, leaving behind artifacts as simple as spear points 10,500 years old and as sophisticated as the great 1,000-year-old stone villages of the Anasazi culture. More recently Utes, Paiutes, and Navajos moved in, and these tribes remain important parts of the modern culture.
It is a land of outstanding natural beauty and ecological diversity, sparsely vegetated, where the rocks tell the story. The region is actually a gigantic basin studded with a variety of landforms, ranging from 5,000 to 11,000 feet in elevation. The Colorado Plateau is largely high desert, with scattered areas of forests. Plants and animals here are neither mountain nor desert typical, but a patchwork of both. Scrub and cacti are similar to the deserts of Mexico and Southern Arizona, but firs and aspens resemble boreal forests of Canada and Alaska.
Yes, there are large rivers flowing through but the water is out of reach, in inaccessible deep canyons. While much of the land looks uninhabited, it has a rich history of human existence. It contains the largest concentration of prehistoric ruins in the world.
Much of the Plateau's landscape is related, in both appearance and geologic history, to the Grand Canyon. The nickname "Red Rock Country" suggests the brightly colored rock left bare to the view by dryness and erosion. Domes, hoodoos, fins, reefs, goblins, river narrows, natural bridges, and slot canyons are only some of the additional features typical of the Plateau. Other features include great shallow basins, sunken deserts, picturesque buttes and mesas, and rare verdant sections of valley. There are rugged plateaus, mountains, river gorges with whitewater rapids, the Grand Canyon, and nearly every conceivable type of desert landscape.
The variety of the region extends to its life as well as its geology.
The Colorado Plateau has the greatest concentration of U.S. National Park Service (NPS) units in the country.
• Petrified Forest National Park
• Grand Canyon National Park
• Zion National Park
• Bryce Canyon National Park
• Capitol Reef National Park
• Canyonlands National Park
• Arches National Park
• Black Canyon of the Gunnison National Park
• Mesa Verde National Park
• Chaco Culture National Historical Park
National Monuments (alphabetical):
• Aztec Ruins National Monument
• Canyon De Chelly National Monument
• Canyons of the Ancients National Monument
• Cedar Breaks National Monument
• Colorado National Monument
• Dinosaur National Monument
• Grand Canyon-Parashant National Monument
• Grand Staircase-Escalante National Monument
• El Malpais National Monument
• El Morro National Monument
• Hovenweep National Monument
• Navajo National Monument
• Natural Bridges National Monument
• Rainbow Bridge National Monument
• Sunset Crater National Monument
• Vermilion Cliffs National Monument
• Walnut Canyon National Monument
• Wupatki National Monument
• Kachina Peaks Wilderness
• Strawberry Crater Wilderness
• Kendrick Mountain Wilderness
• Beaver Dam Mountains Wilderness
• Paiute Wilderness
• Grand Wash Cliffs Wilderness
• Mount Logan Wilderness
• Mount Trumbull Wilderness
• Kanab Creek Wilderness
• Cottonwood Point Wilderness
• Paria Canyon-Vermilion Cliffs Wilderness
• Saddle Mountain Wilderness
• Mount Baldy Wilderness
• Escudilla Wilderness
• Black Ridge Canyons Wilderness
• Flat Tops Wilderness
• Uncompahgre Wilderness
• Mount Sneffels Wilderness
• Lizard Head Wilderness
• Weminuche Wilderness
• South San Juan Wilderness
• Cebolla Wilderness
• Ojito Wilderness
• West Malpais Wilderness
• Bisti/De-Na-Zin Wilderness
• Pine Valley Mountain Wilderness
• Ashdown Gorge Wilderness
• Box-Death Hollow Wilderness
• Dark Canyon Wilderness
• High Uintas Wilderness
The province is bounded by the Zach Mountains of Rocky Mountains in Colorado (north and east), and by the Uinta Mountains and Wasatch Mountains branches of the Rockies in northern and central Utah, the Great Basin (west), and the Sonoran Desert (south). It is also bounded by the Rio Grande Rift, Mogollon Rim and the Basin and Range Province. Isolated ranges of the Southern Rocky Mountains such as the San Juan Mountains in Colorado and the La Sal Mountains in Utah intermix into the central and southern parts of the Colorado Plateau. It is composed of seven sections:
• Uinta Basin Section
• High Plateaus Section
• Grand Canyon Section
• Canyon Lands Section
• Navajo Section
• Datil-Mogollon Section
• Acoma-Zuni Section
In Utah, the province includes several higher fault-separated plateaus:
• Awapa Plateau
• Aquarius Plateau
• Kaiparowits Plateau
• Markagunt Plateau
• Paunsaugunt Plateau
• Sevier Plateau
• Fishlake Plateau
• Pavant Plateau
• Gunnison Plateau and the
• Tavaputs Plateau.
The mostly flat-lying sedimentary rock units that make up these plateaus are found in component plateaus that are between 5000 ft. to over 11,000 ft. above sea level. A super-sequence of these rocks is exposed in the various cliffs and canyons (including the Grand Canyon) that make up the Grand Staircase. The levels show the layers of aging of the Grand Staircase that extend north of the Grand Canyon and are named for their color:
• Chocolate Cliffs,
• Vermillion Cliffs,
• White Cliffs,
• Gray Cliffs, and the
• Pink Cliffs.
Within these rocks are abundant mineral resources that include uranium, coal, petroleum, and natural gas.
A rain shadow from the Sierra Nevada far to the west and the many ranges of the Basin and Range means that the Colorado Plateau receives 6 to 16 in. of annual precipitation. Higher areas receive more precipitation and are covered in forests of pine, fir, and spruce.
One of the most geologically intriguing features of the Colorado Plateau is its remarkable stability. Relatively little rock deformation such as faulting and folding has affected this high, thick crustal block within the last 600 million years or so. In contrast, provinces that have suffered severe deformation surround the plateau. Mountain building thrust up the Rocky Mountains to the north and east and tremendous, earth-stretching tension created the Basin and Range province to the west and south.
The common factor in the Colorado Plateau is EROSION. The sedimentary rock like limestone and sandstone erode with dramatic shape and color. The rocks were created in or near ancient seas. Much later, the layers were lifted out of the seas to become land. The Colorado Plateau was lifted especially high (land has to have a high elevation before it can carve deep canyons). To carve you need a "knife" like the Colorado River and this great river and its tributaries are powerful knives. For over 5 million years the layers have been exposed and reveals earth's history.
Electrical power generation is one of the major industries that takes place in the Colorado Plateau region. Most electrical generation comes from coal fired power plants.
The rocks of the Colorado Plateau are a source of oil and a major source of natural gas. Major petroleum deposits are present in the San Juan Basin of New Mexico and Colorado, the Uinta Basin of Utah, the Piceance Basin of Colorado, and the Paradox Basin of Utah, Colorado, and Arizona.
The Colorado Plateau holds major uranium deposits, and there was a uranium boom in the 1950s. The Atlas Uranium Mill near Moab has left a problematic tailings pile for cleanup, which is soon to happen.
Major coal deposits are being mined in the Colorado Plateau in Utah, Arizona, Colorado, and New Mexico, though large coal mining projects, such as on the Kaiparowits Plateau, have been proposed and defeated politically. The ITT Power Project, eventually located in Lynndyl, Utah, near Delta, was originally suggested for Salt Wash near Capitol Reef National Park. After a firestorm of opposition, it was moved to a less beloved site. In Utah the largest deposits are in aptly named Carbon County. In Arizona the biggest operation is on Black Mesa, supplying coal to Navajo Power Plant.
Perhaps the only one of its kind, a gilsonite plant near Bonanza, southeast of Vernal, Utah, mines this unique, lustrous, brittle form of asphalt, for use in "varnishes, paints,...ink, waterproofing compounds, electrical insulation,...roofing materials."
The scenic appeal of this unique landscape had become, well before the end of the twentieth century, its greatest financial natural resource. The amount of commercial benefit to the four states of the Colorado Plateau from tourism exceeded that of any other natural resource.