أخدود

هذا المقال يتضمن أسماءً أعجمية تتطلب حروفاً إضافية (پ چ ژ گ ڤ ڠ).
لمطالعة نسخة مبسطة، بدون حروف إضافية
The Grand Canyon, Arizona, at the confluence of the Colorado River and Little Colorado River

A canyon (بالاسپانية: cañón; archaic British English spelling: cañon)[1] or gorge is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales.[2] 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,[3] 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.

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أمثلة بارزة

The following list contains only the most notable canyons of the world, arranged by continent and then country.

أفريقيا

ناميبيا

South Africa

Tanzania

Americas

Argentina

Brazil


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Canada

Colombia

Mexico

Peru

United States

آسيا

One of the Three Gorges of the Yangtze river, China
The gorge of the Kabul River in Afghanistan


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الصين

الهند

Taiwan

Others

Cheddar Gorge, England

Europe

United Kingdom

France

Spain

أوكرانيا

غيرها

Joffre Gorge, Karijini National Park, Australia

Oceania

Australia

New Zealand

Canyons on other planetary bodies

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.

انظر أيضاً

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الهوامش

  1. ^ "canon". archaic spelling of canyon
  2. ^ Society, National Geographic (20 May 2011). "canyon". National Geographic Society (in الإنجليزية).
  3. ^ Ward Cameron. "Understanding Canyon Formation".
  4. ^ Valerio Poggiali, Marco Mastrogiuseppe, Alexander G. Hayes, Roberto Seu, Samuel P. D. Birch, Ralph Lorenz, Cyril Grima, Jason D. Hofgartner, "Liquid-filled Canyons on Titan", 9 August 2016, http://onlinelibrary.wiley.com/doi/10.1002/2016GL069679/abstract

وصلات خارجية