A Land to Inspire our Spirit
Rock Form
Vishnu Basement Rocks
Tectonic plates move slowly across Earth’s surface. Almost two billion years ago a plate carrying an island chain and the plate that became North America collided. Heat and pressure from this process changed those existing rock layers into dark metamorphic rock, the basement of the canyon. Molten rock squeezed into cracks and hardened as light bands of granite.
Grand Canyon Supergroup
The red shale, fossil-bearing lime-stone, and dark lava of the Grand Canyon Supergroup are revealed in only a few areas. The many strata of the Supergroup accumulated in basins formed as the land mass pulled apart. The expansion caused blocks to tilt, inclining the Supergroup layers. The same process caused Nevada’s alternating basins and mountain ranges.
Layered Paleozoic Rocks
Nearly horizontal layers of sedimentary rocks comprise the upper two-thirds of the canyon’s walls. These rocks formed near sea level and at the edge of the continent. The remains of marine life accumulated on the ocean floor to form limestone. Rivers deposited sediments in swamps and deltas that then became mudstones. Dunes solidified into sandstone.
Deep Time, changing Landscapes
Grand Canyon reveals a beautiful sequence of rock layers that serve as windows into time. The carving of the canyon is only the most recent chapter, a geologic blink of an eye, in a long story. That long story includes rock nearly two billion (2,000,000,000) years old in the bottom of the canyon, land masses colliding and drifting apart, mountains forming and eroding away, sea levels rising and falling, and relentless forces of moving water. Several factors make Grand Canyon’s geology remarkable. Many canyons form as rivers cascade among mountain peaks, but Grand Canyon sits incised into an elevated plateau. The desert landscape exposes the geology to view. It is not hidden under a cloak of vegetation. The strata revealed preserve a lengthy, although incomplete, record of Earth’s history. Take time to pause on the rim and enjoy this work of the ages.
Uplift Occurs
The Colorado Plateau Rises
About 70 million years ago the Rocky Mountain began to form, pushed up as the North American Plate overrode the pacific plate. As a result, a large section of what is now eastern Utah, northern Arizona, western Colorado, and a corner of New Mexico rose from sea level to elevations of thousands of feet, forming the Colorado plateau. This uplift occurred with remarkably little tilting or deformation of the sedimentary layers.
The stage was set for the carving of Grand Canyon.
Top photo: Grand Canyon and the North Rim as seen from Grand Canyon Village. South Rim.
Erosion Sculpts
Canyon Carving
By five of six million years ago the Colorado River flowed across the Colorado plateau on its way from the Rocky Mountains to the Gulf of California. Each rain Washed sparsely vegetated desert soils into the river. A steep gradient and heavy sediment loads created a powerful tool for erosion. The river’s volume varied seasonally and over times. As the last Ice Age ended 12,000 years ago, the flow may have been 10 times today’s volume.
As the river cuts down, the canyon deepens. Tributaries erode into the canyon’s sides, increasing its width, Erosion carves faster into the softer rock layers, undermining harder layers above. With no foundation these layers collapse, forming the cliffs and slopes profile of the canyon. Erosion wears away the ridges separating adjacent side canyons, leaving butter and pinnacles.
Age of Earth
4,500 million
Communities of Life
Riparian
Water is the lifeblood of Grand Canyon. Nowhere does water so transform landscapes as in the desert. A small seep, a cascading tributary, or the ever-flowing Colorado River supports an abundance of life fostered by the presence of water.
Extreme changes in elevation, exposure, and climate support a remarkable range of plant and animal communities unusually close together.
Desert
Three of the four North American deserts come together in low elevations of the park. Mesquite trees from the Sonoran Desert line portion of the river. Black-brush sparsely cloaks the inner canyon in typical Great Basin Desert fashion. Joshua trees represent Mojave Desert.
Pinyon-Juniper
A dwarf forest of pinyon pine and juniper covers vast stretches of the mid-elevation southwest. The scale-like, wax-coated leaves of the juniper and the short, two-needled clusters of the pinyon conserve water in a dry land.
Ponderosa Pine
Ponderosa pines thrive with more rainfall and deeper soils. Smell the bark-vanilla or butterscotch? Tassel-cared squirrels depend on the ponderosa for food shelter. North Rim’s Kaibab squirrel, now isolated for generations, sports different colors than South Rim’s Abert’s squirrel.
Mixed Conifer
The higher elevation of the North Rim captures more precipitation and supports a diverse forest of fir, spruce, and Douglas fir. Aspen trees shimmer golden in the fall. Watch for mule deer and wild turkeys in meadows that interrupt the thick forest.
People of the canyon
Grand Canyon has sustained people both materially and spiritual for thousands of the year. Clovis hunters found a wetter, more verdant area, with large mammals that are now extinct. Ancestral Puebloan people relied on agriculture, living off the land in a different way. Visitors today come from a world these earlier groups could never imagine. This special landscape offers an opportunity to consider the powerful ties between people and place.
PALEO-INDIAN
12,000-9,000 years ago
Folsom point
Use spears to hunt large mammals
The whole canyon and everything in it is sacred to us, all around, up and down.-Rex Tilousi, Havasupai elder
ARCHAIC
9,000-2,500 years ago
Split-twig figurine
Hunt smaller animals and gather wild foods.
BASKETMAKER
2,500-1,200 years ago
Basket
Introduce the bow and arrow, pit houses, pottery, and agriculture.
ANCESTRAL PUEBLOAN 800-1300 Common Era
Bowl
Masonry architecture; grow corn, beans, and squash; population declines after 1150.
LATE PREHISTORIC 1300-1500 CE
Ancestors to Hualapai, Havasupai, Southern Paiute, and Navajo move into the area.
RECENT PAST
1540 Hopis guide Spanish explorers to south Rim.
1869 John Wesley Powell leads expedition through Grand Canyon. 1901 Railroad arrives at south Rim, greatly boosting tourism (right).
1908 President Theodore Roosevelt sets aside Grand Canyon National Monument.
1919 Congress creates Grand Canyon Nation Park.
Welcome to Grand Canyon National Park
See The Guide newspaper, available at all entrance stations and visitors centers in English, German, French, Spanish, Italian, Japanese, Korean, and Chines, for detailed maps and information about parking, free shuttle buses (South Rim), visitor centers, food, lodging, camping, mule or raft trips, bus and air tours, park ranger programs, and day or overnight hiking. It provides information to make your visit to Grand Canyon National Park a success. Please read it. An Accessibility Guide is also available.
Safety and Regulations
Stay on trails and away from cliffs. Thunderstorms are common in summer. Seek shelter and stay away from the rim and exposed areas when lightning threatens. Launching, landing, or operating an unmanned aircraft is prohibited inside Grand Canyon National Park. Pets must be leashed. Pets are permitted in developed areas above the rim, but not on shuttle buses, in buildings, or on trails into the Grand Canyon. All vehicles, including mountain bikes, are restricted to maintained roads. Not all primitive roads are shown; use topographic maps for road and trail information. When hiking, carry food and water. Wear sun protection and appropriate clothing and shoes. Hiking to the Colorado River and back in one day is dangerous. It is illegal to feed deer, squirrels, or other animals. For firearms regulations check the park website.
Emergencies call 911
Accessibility
We strive to make our facilities, services, and programs accessible to all. Call or check our website.
Grand Canyon National Park is one of over 400 parks in the National Park System. To learn more about national parks and national park service programs in America’s communities visit www.nps.gov.
More information
Grand Canyon national Park
PO Box 129
Grand Canyon, AZ 86023
928-638-7888
See the Guide newspaper for maps of Grand Canyon Village, the South Rim, and North Rim.
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