Canyon
A canyon is a prominent landform characterized by a deep, V-shaped valley with steep walls, primarily formed through the erosive power of fast-moving rivers over millions of years. Canyons can also arise through tectonic activity, where the movement of Earth's plates creates elevation changes, or through ocean currents that shape submarine canyons. The most renowned canyon is the Grand Canyon in Arizona, known for its immense size and geological significance, with layers of rock that provide insights into the Earth's history and climate changes. Other types of canyons include box canyons, which have a single entry point, and slot canyons, which are narrow but reach great depths. Canyons, often found in arid regions, also serve as important sites for scientific research, particularly in studying fossils and geological history. They attract millions of visitors worldwide, highlighting their natural beauty and the allure of exploring such majestic landscapes. Notable examples beyond the Grand Canyon include the Yarlung Zangbo Grand Canyon in Tibet, the Gorges Du Verdon in France, and Colca Canyon in Peru, each showcasing unique features and geological significance.
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Canyon
A type of land formation, a canyon is a deep, V-shaped valley with steep walls in the earth's crust. Canyons are formed when a fast-moving river cuts through rock resistant to erosion and weathering. The process occurs over millions of years. Canyons also form through the movement of tectonic plates. The landform is typically found in arid areas, where the valley walls are not worn away by regular rainfall. Canyons can also be carved by powerful currents on the ocean floor. In addition to river canyons, other types of canyons include box canyons, slot canyons, and submarine canyons. By studying a canyon and its rock layers, scientists can learn about a region's geology, history, ecosystems, and climate changes.
Background
The term canyon is derived from the Spanish word canon, which means "tube." Valleys that look similar to canyons but are smaller and steeper are called gorges.
Strong, swift currents are often the power behind the creation of canyons. A river's water pressure can slice deep into the ground below it. As the sediments are deposited downstream, a narrow channel develops.
Erosion and weathering play a vital role in shaping canyons. The river, wind, and rain diminish the less resistant layers of rock over time. The freezing and subsequent expansion of water also erode the rock. When water seeps into cracks in the stone, it freezes and pushes against the cracks. The cracks grow bigger, causing pieces of rock to fall off. As more of the stone chips away, the canyon becomes wider at the top.
After the softer rock layers wear away on the surface, cliffs form, as the harder sedimentary layers remain exposed on the valley walls.
Tectonic activity also causes elevation changes that create canyons. When the earth's tectonic plates shift, their movement can raise a geographical location higher than the area around it. This occurrence is known as tectonic uplift. Canyons have been carved by glaciers and rivers that run through the elevated areas formed by tectonic uplift.
The most famous canyon in the world—the Grand Canyon in Arizona—is the result of tectonic uplift. The Colorado River carved the Grand Canyon along the Colorado plateau, which was raised millions of years ago by the shifting of tectonic plates. The largest canyon in the United States, the Grand Canyon measures 277 miles long, 6,000 feet deep, and 18 miles at its widest point.
Geologists are not sure how old the Grand Canyon is. Its age is estimated to be between five million and seventy million years old. Experts continue to study its nearly forty layers of rock— including a cross-section that is about two billion years old—with the hope of unlocking the Grand Canyon's mysteries and determining its geologic evolution.
Overview
River canyons are the most well-known type of canyons, but the land formation can be categorized into other types.
A box canyon is a hard-rock canyon with an opening on just one side. Cliffs make up at least three sides. With access limited to one entry point, box canyons have been used as natural corrals in the American West.
Slot canyons form in softer rock. They are narrow in width but can reach deep, measuring hundreds of feet down. Their walls, which are often smooth, are challenging to climb.
Submarine canyons develop underneath oceans. Their shape and erosional forms are similar to onshore river canyons. Some are formed by rivers that flowed into the ocean and cut across the continental shelf, the underwater land that extends outward from the edge of a continent. Other submarine canyons are created when strong ocean currents carrying sediment reach into the ocean floor.
The natural splendor of the world's canyons attracts tourists from around the globe. The Grand Canyon alone draws five million visitors a year.
Other notable canyons convey the wonder of nature. The Yarlung Zangbo Grand Canyon in Tibet, China, is the world's deepest canyon, measuring more than 17,490 feet, and one of the longest at 310 miles. The Gorges Du Verdon in France, called "The Grand Canyon of Europe," drops down sharply to a stunning turquoise-green river. Colca Canyon in Peru, one of the country's most popular landmarks, is twice as deep as the Grand Canyon.
While canyons have grown into tourist attractions, the landforms offer scientists unlimited opportunities for study.
Canyons are integral to the study of fossils. Fossils are more likely to be preserved in parched environments, where canyons commonly form. The sedimentary layers surrounding fossils can make it easier for scientists to estimate a fossil's age.
The layers of rock and carving of plateaus allow experts to learn about a region's geological history, stream erosion, and tectonic movements. Further study can track the changes in an area's climate over time and the kinds of organisms that inhabited the area.
Scientists look to canyons to anticipate how the terrain may change in the years ahead. Studying the layers of sediment and their thickness can help geologists learn how an area's environment affects rock formations. Tracing erosion patterns can uncover the climate changes a region has experienced over time. Erosion patterns can also be used to track the speed of the water that flows through a canyon.
The Grand Canyon has been under geological study since 1858. Experts have used the data collected to anticipate future alterations to the canyon's landscape. Geologists have determined the Grand Canyon is eroding at a rate of one foot every two hundred years. Based on this estimate, they predict the Grand Canyon will grow deeper while the Colorado River continues to chisel away at the riverbed.
Bibliography
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"Geologic Formations." National Park Service, 14 Mar. 2019, www.nps.gov/grca/learn/nature/geologicformations.htm. Accessed 17 Jan. 2023.
"Grand Canyon Geology." National Geographic, explorethecanyon.com/geology-of-the-grand-canyon. Accessed 14 Nov. 2016.
"Grand Canyon Habitat." Grand Canyon Association, www.grandcanyon.org/learn/canyon-facts/grand-canyon-habitat. Accessed 14 Nov. 2016.
"Grand Canyon National Park." National Geographic, travel.nationalgeographic.com/travel/national-parks/grand-canyon-national-park. Accessed 14 Nov. 2016.
"Submarine Canyons." Sanctuary Integrated Monitoring Network, www.sanctuarysimon.org/regional‗sections/submarineCanyons/overview.php?sec=sc. Accessed 14 Nov. 2016.
Valera, Stephanie. "50 Amazing Canyons and Gorges of the World." Weather Channel, 15 May 2015, weather.com/travel/news/amazing-canyons-gorges. Accessed 14 Nov. 2016.