A canyon (; archaic British English spelling: cañon), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency to cut through underlying surfaces, eventually wearing away rock layers as sediments are removed downstream. A river bed will gradually reach a baseline elevation, which is the same elevation as the body of water into which the river drains. The processes of weathering and erosion will form canyons when the river's headwaters and estuary are at significantly different elevations, particularly through regions where softer rock layers are intermingled with harder layers more resistant to weathering.
A canyon may also refer to a rift between two mountain peaks, such as those in ranges including the Rocky Mountains, the Alps, the Himalayas or the Andes. Usually, a river or stream carves out such splits between mountains. Examples of mountain-type canyons are Provo Canyon in Utah or Yosemite Valley in California's Sierra Nevada. Canyons within mountains, or gorges that have an opening on only one side, are called box canyons. Slot canyons are very narrow canyons that often have smooth walls.
Steep-sided valleys in the seabed of the continental slope are referred to as submarine canyons. Unlike canyons on land, submarine canyons are thought to be formed by turbidity currents and landslides.
Etymology
The word "canyon" is Spanish in origin (, ), with the same meaning. The word canyon is generally used in North America, while the words gorge and ravine (French in origin) are used in Europe and Oceania, though gorge and ravine are also used in some parts of North America. In the United States, place names generally use canyon in the southwest (due to their proximity to Spanish-speaking Mexico) and gorge in the northeast (which is closer to French Canada), with the rest of the country graduating between these two according to geography. In Canada, a gorge is usually narrow while a ravine is more open and often wooded. The military-derived word defile is occasionally used in the United Kingdom. In South Africa, kloof (in Krantzkloof Nature Reserve) is used along with canyon (as in Blyde River Canyon) and gorge (in Oribi Gorge).
Formation
Most canyons were formed by a process of long-time erosion from a plateau or table-land level. The cliffs form because harder rock strata that are resistant to erosion and weathering remain exposed on the valley walls.
Canyons are much more common in arid areas than in wet areas because physical weathering has a more localized effect in arid zones. The wind and water from the river combine to erode and cut away less resistant materials such as shales. The freezing and expansion of water also serves to help form canyons. Water seeps into cracks between the rocks and freezes, pushing the rocks apart and eventually causing large chunks to break off the canyon walls, in a process known as frost wedging. Canyon walls are often formed of resistant sandstones or granite.
Sometimes large rivers run through canyons as the result of gradual geological uplift. These are called entrenched rivers, because they are unable to easily alter their course. In the United States, the Colorado River in the Southwest and the Snake River in the Northwest are two examples of tectonic uplift.
Canyons often form in areas of limestone rock. As limestone is soluble to a certain extent, cave systems form in the rock. When a cave system collapses, a canyon is left, as in the Mendip Hills in Somerset and Yorkshire Dales in Yorkshire, England.
Box canyon
A box canyon is a small canyon that is generally shorter and narrower than a river canyon, with steep walls on three sides, allowing access and egress only through the mouth of the canyon. Box canyons were frequently used in the western United States as convenient corrals, with their entrances fenced.
Largest The definition of "largest canyon" is imprecise, because a canyon can be large by its depth, its length, or the total area of the canyon system. Also, the inaccessibility of the major canyons in the Himalaya contributes to them not being regarded as candidates for the biggest canyon. The definition of "deepest canyon" is similarly imprecise, especially if one includes both mountain canyons (which do not have a well-defined rim elevation) and canyons cut through relatively flat plateaus (which have a somewhat well-defined rim elevation).
The Yarlung Tsangpo Grand Canyon (or Tsangpo Canyon), along the Yarlung Tsangpo River in Tibet, China, is regarded by some as the deepest canyon on Earth at . It is slightly longer than Grand Canyon in the United States. Others consider the Kali Gandaki Gorge in midwest Nepal to be the deepest canyon, with a difference between the level of the river and the peaks surrounding it.
Vying for the deepest canyon in the Americas is the Cotahuasi Canyon and Colca Canyon, in southern Peru. Both have been measured at over deep.
Grand Canyon of northern Arizona in the United States, with an average depth of and a volume of , is one of the world's largest canyons. It was among the 28 finalists of the New 7 Wonders of Nature worldwide poll. (Some referred to it as one of the seven natural wonders of the world.)
The largest canyon in Europe is Tara River Canyon, ~ deep.
The largest canyon in Africa is the Fish River Canyon in Namibia, ~ deep.
In August 2013, the discovery of Greenland's Grand Canyon was reported, based on the analysis of data from Operation IceBridge. It is located under an ice sheet. At long, it is believed to be the longest canyon in the world.
Despite not being quite as deep or long as the Grand Canyon, the Capertee Valley in Australia is actually 1 km wider than the Grand Canyon, making it the widest canyon in the world.
Cultural significance Some canyons have notable cultural significance. Evidence of archaic humans has been discovered in Africa's Olduvai Gorge. In the southwestern United States, canyons are important archeologically because of the many cliff-dwellings built in such areas, largely by the ancient Pueblo people who were their first inhabitants.
Notable examples The following list contains only the most notable canyons of the world, grouped by region.
Africa
Namibia Fish River Canyon
South Africa Blyde River Canyon, Mpumalanga Oribi Gorge, KwaZulu-Natal
Tanzania Olduvai Gorge
Americas
Argentina Atuel Canyon, Mendoza Province
Brazil Itaimbezinho Canyon, Rio Grande do Sul
Bolivia Torotoro River Canyon
Canada Grand Canyon of the Stikine, British Columbia Horseshoe Canyon, Alberta Niagara Gorge, Ontario Ouimet Canyon, Ontario Fraser Canyon, British Columbia Coaticook Gorge, Quebec Thompson Canyon, British Columbia
Colombia Chicamocha Canyon, Santander Department
Mexico Barranca de Oblatos, Jalisco Copper Canyon, Chihuahua Sumidero Canyon, Chiapas
Peru Cañón del Pato, Ancash Region Colca Canyon, Arequipa Region Cotahuasi Canyon, Arequipa Region
United States American Fork Canyon, Utah Antelope Canyon, Arizona Apple River Canyon, Illinois Ausable Chasm, New York Big Cottonwood Canyon, Utah Black Canyon of the Gunnison, Colorado Black Hand Gorge, Ohio Blackwater Canyon, West Virginia Blue Creek Canyon, Colorado Bluejohn Canyon, Utah Box Canyon, Colorado Breaks Canyon, Kentucky and Virginia Butterfield Canyon, Utah Cane Creek, Alabama Canyon de Chelly, Arizona Canyonlands National Park, canyons of the Colorado River and its main tributary the Green River, Utah Cheat Canyon, West Virginia Clifton Gorge, Ohio Clifty Canyon, Indiana Cloudland Canyon, Georgia Columbia River Gorge, Oregon and Washington Conkle's Hollow, Ohio Cottonwood Canyon, Utah Crooked River Gorge, Oregon Death Hollow, Utah Desolation Canyon, Utah Dismals Canyon, Alabama Flaming Gorge, Wyoming and Utah Flume Gorge, New Hampshire Glen Canyon, Utah and Arizona Glenwood Canyon, Colorado Gore Canyon, Colorado Grand Canyon, Arizona Grand Canyon of the Yellowstone, Wyoming Grandstaff Canyon, Utah Guffey Gorge, Colorado Gulf Hagas, Maine Hells Canyon, Idaho, Oregon, and Washington Horse Canyon, Utah Kern River Canyon, California Kings Canyon, Utah Kings Canyon, California Leslie Gulch, Oregon Linville Gorge, North Carolina Little Cottonwood Canyon, Utah Little Grand Canyon, Illinois Little River Canyon, Alabama Logan Canyon, Utah Mather Gorge, Maryland Marysvale Canyon, Utah McCormick's Creek Canyon, Indiana Millcreek Canyon, Utah New River Gorge, West Virginia Ninemile Canyon, Utah Ogden Canyon, Utah Oneonta Gorge, Oregon Palo Duro Canyon, Texas Parleys Canyon, Utah Pine Creek Gorge, Pennsylvania Poudre Canyon, Colorado Providence Canyon, Georgia Provo Canyon, Utah Quechee Gorge, Vermont Red River Gorge, Kentucky Rio Grande Gorge, New Mexico Royal Gorge, Colorado Ruby Canyon, Utah Snake River Canyon, Idaho Snow Canyon, Utah Stillwater Canyon, Utah Tallulah Gorge, Georgia Tenaya Canyon, California Tennessee River Gorge, Alabama and Tennessee The Trough, West Virginia Unaweep Canyon, Colorado Uncompahgre Gorge, Colorado Waimea Canyon, Hawaii Walls of Jericho, Alabama Weber Canyon, Utah Westwater Canyon, Utah Wolverine Canyon, Utah White Canyon, Utah Zion Canyon, Utah
Asia
China Three Gorges, Chongqing Tiger Leaping Gorge, Yunnan Yarlung Zangbo Grand Canyon, Tibet Autonomous Region
India Gandikota, Kadapa District, Andhra Pradesh Raneh Falls, Chatarpur district, Madhya Pradesh Idukki, Western Ghats, Kerala
Indonesia Cukang Taneuh, Pangandaran, West Java Sianok Valley, Bukittinggi, West Sumatra
Others Afghanistan – Tang-e Gharu Iran – Haygher Canyon in Fars province Iraq - Rawandiz Gorge in Kurdistan Region Japan – Kiyotsu Gorge in Niigata Prefecture Japan – Tenryū-kyō in Nagano Prefecture Kazakhstan – Charyn Canyon Nepal – Kali Gandaki Gorge Russia – Delyun-Uran (Vitim River) Pakistan – Indus River Gorge through the Himalaya Taiwan – Taroko Gorge in Hualien County Turkey – Ulubey Canyon in Uşak Province Turkey – Ihlara Valley in Aksaray Province Syria – Rabweh in Damascus
Europe
United Kingdom Avon Gorge, Bristol Burrington Combe, Somerset Cheddar Gorge, Somerset Corrieshalloch Gorge, Ullapool Ebbor Gorge, Somerset Gordale Scar, North Yorkshire Winnats Pass, Derbyshire
France Gorges de l'Ardèche, Auvergne-Rhône-Alpes Gorges de Daluis, Provence-Alpes-Côte d'Azur Gorges du Tarn, Occitanie Grands Goulets, Auvergne-Rhône-Alpes Verdon Gorge, Alpes-de-Haute-Provence
Ukraine
Aktove canyon Buky Canyon Dniester Canyon
Others
Albania – Osum Canyon, Kanionet e Skraparit Albania/Montenegro – Cem Bosnia and Herzegovina – Rakitnica, Drina, Neretva, Vrbas, Unac, Čude, Ugar, Prača, Bulgaria – Trigrad Gorge, Kresna Gorge, Iskar Gorge Finland – Korouoma Canyon, Kevo Canyon Germany – Partnach Gorge Greece – Vikos Gorge, Samaria Gorge Greenland – Greenland's Grand Canyon Iceland – Fjaðrárgljúfur Canyon Kosovo – Rugova Canyon, White Drin Canyon, Kacanik Gorge North Macedonia – Matka Canyon Montenegro – Morača, Piva Montenegro/Bosnia and Herzegovina – Tara River Canyon Montenegro/Serbia – Ibar Norway – Sautso Canyon Poland/Slovakia – Dunajec River Gorge Russia – Sulak Canyon, Dagestan Serbia – Lazar's Canyon Serbia/Bosnia and Herzegovina – Lim Serbia/Romania – Iron Gates Slovenia – Vintgar Gorge Switzerland – Aare Gorge
Oceania Australia Joffre Gorge, Karijini National Park, Western Australia Katherine Gorge, Northern Territory Kings Canyon, Northern Territory Murchison River Gorge, Western Australia Jamison Valley, New South Wales Capertee Valley, New South Wales – the world's second-widest canyon Shoalhaven Gorge, New South Wales Werribee Gorge, Victoria The Slot Canyons of the Blue Mountains, New South Wales
New Zealand Manawatū Gorge, North Island Skippers Canyon, South Island
Solar System Ithaca Chasma on Saturn's moon Tethys Valles Marineris on Mars, the largest-known canyon in the Solar System