Grand Canyon

A Land To Inspire Our Spirit

Grand Canyon-- one of Earth's most powerful, inspiring landscapes – overwhelms our senses. Its story tells of geologic processes played out over unimaginable time spans as a unique combination of size, colour, and dazzling forms: 277 river miles (446 km) long, up to 18 miles (29 km) wide, and a mile (1.6km) deep. Its rugged landscape hosts a fascinating variety of plant and animal communities, from the desert next to the Colorado River deep in the canyon to montane forest atop its North Rim.

Humans have played parts in the story for thousands of years. Broken spear points, enigmatic split-twig figurines, decorated pots, abandoned mines, and historic hotels suggest some who have called the canyon home. Enjoy the views, discover the history, and learn about the plant and history still being written. Grand Canyon National Park is a stewards is to pass in this gift, pristine and preserved, to future generations.

Vishnu Basement Rocks

Tectonic plates moves slowly across Earth’s surface. Almost 2 billion years ago plate carrying island arcs and the plate that became North America collided. Heat and pressure from this process changed those existing rock, the basement of the canyon. Molten rock then squeezed into cracks and hardened as light bands of granite.

Grand Canyon Supergroup

The red shale, fossil-algae-bearing limestone, 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 rotate, tilting the Superproup layers. The same process caused Nevads’s alternating basins and mountain ranges.

Paleozoic Sedimentary 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 a 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.

The Colorado Plateau Rises

About 70 million years ago the Rocky Mountains began to form, pushed up as the North American Plate overrode the Pacific Plate. In the process a large section of what is now Utah, northern Arizona, western Colorado, and a corner of new Mexico rose form 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.

Canyon Carving

By five or 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 time. 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 layer, 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 buttes and pinnacles.

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 2 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 length, although incomplete, record of earth’s history. Take time to pause on the rim and enjoy this work of ages.

"What is Next....."