A canyon (from Spanish : cañón ; 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.
20-686: Niagara Gorge is an 11 km (6.8 mi) long canyon carved by the Niagara River along the Canada–United States border , between the U.S. state of New York and the Canadian province of Ontario . It begins at the base of Niagara Falls and ends downriver at the edge of the geological formation known as the Niagara Escarpment near Queenston, Ontario , where the falls originated about 12,500 years ago. The position of
40-703: Is 120 km south of Durban . Oribi Gorge, cut by the Mzimkulwana River , is the eastern gorge of two gorges that cut through the Oribi Flats (flat sugarcane farmlands) of KwaZulu-Natal. The western gorge was formed by the Mzimkulu River . The gorge is approximately 400 metres (1,300 ft) deep, and almost 5 kilometres (3.1 mi) wide at its widest. Erosion by these rivers have carved out nearly 30 kilometres (19 mi) of spectacular kloofs and crags, covered with subtropical vegetation. In
60-579: Is actually 1 km wider than the Grand Canyon, making it the widest canyon in the world. 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. The following list contains only
80-676: 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 ). 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
100-599: Is similarly imprecise, especially if one includes mountain canyons, as well as 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 , is regarded by some as the deepest canyon on Earth at 5,500 metres (18,000 ft). It is slightly longer than the Grand Canyon in
120-598: 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. 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
140-644: Is the Fish River Canyon in Namibia . 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 750 kilometres (470 mi) 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
160-1259: The Niagara Parkway in Ontario. Matthew Webb , the first person to swim the English Channel , drowned trying to swim the rapids of the gorge as part of a publicity stunt in 1883. Canyon 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
180-461: 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
200-642: 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 . The word canyon is Spanish in origin ( cañón , pronounced [kaˈɲon] ), 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
220-460: The western United States as convenient corrals, with their entrances fenced. 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 their not being regarded as candidates for the biggest canyon. The definition of "deepest canyon"
SECTION 10
#1732786668863240-596: The United States, with an average depth of 1,600 metres (5,200 ft) and a volume of 4.17 trillion cubic metres (147 trillion cubic feet), 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 . The largest canyon in Africa
260-627: The United States. Others consider the Kali Gandaki Gorge in midwest Nepal to be the deepest canyon, with a 6,400-metre (21,000 ft) 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 3,500 metres (11,500 ft) deep. The Grand Canyon of northern Arizona in
280-746: 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
300-589: The dangers this presents, kayaking the gorge has generally been prohibited. On multiple occasions, the rapids of the gorge have claimed the lives of people attempting to run them. However, on isolated occasions, world-class experts have been permitted to navigate the stretch. Tourists can traverse the rapids of the Niagara Gorge on commercial tours in rugged jetboats, which are based at Niagara-on-the-Lake, Ontario , at Lewiston, New York , at Youngstown, New York , and in midsummer at Niagara Glen Nature Centre on
320-412: The falls has receded upstream toward Lake Erie because of the falling waters' slow erosion of the riverbed's hard Lockport dolomite (a form of limestone that is the surface rock of the escarpment), combined with rapid erosion of the relatively soft layers beneath it. This erosion has created the gorge. The force of the river current in the gorge is one of the most powerful in the world; because of
340-547: The gorge, the dense forest on the sandstone slopes is home to various small mammals, while the large leguaans excavate their burrows along the riverbanks. At the base of the cliffs of both gorges the basement rocks are part of the Namaqua-Natal Metamorphic Province , which is over 1000 million years old. The cliffs themselves are formed by Msikaba formation sandstones deposited by fluvial environment about 365 million years ago. Downstream from
360-627: The gorges, is a large surface mine producing cement from a limestone deposit. The road through Oribi Gorge was built by Italian prisoners of war . Oribi Gorge derives its name from the oribi , a small antelope that lives in the gorges. Oribi Gorge Nature Reserve is a park located along the bottom of the Oribi Gorge at the confluence of the Mzimkulu River and Mximkulwana River, being approximately 27 kilometres (17 mi) long, and 1 kilometre (0.62 mi) wide at its widest point. It
380-412: The most notable canyons of the world, grouped by region. Venus has many craters and canyons on its surface. The troughs on the planet are part of a system of canyons that is more than 6,400 km long. [REDACTED] Environment portal Oribi Gorge Oribi Gorge is a canyon in southern KwaZulu-Natal , South Africa , 35 kilometres north-west of Port Shepstone , which itself
400-456: 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
#862137