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A canyon is a vast, bounded valley with steep, rising sides. Canyons are formed by weathering and erosion. Over millions of years, the land is continuously worn away by water. Rocks and silt on the riverbed are carried away by the river, which further gouges out a narrow channel-shaped landscape. |
A canyon is a deep, narrow valley with steep sides. “Canyon” comes from the Spanish word cañon, which means “tube” or “pipe.” The term “gorge” is often used to mean “canyon,” but a gorge is almost always steeper and narrower than a canyon.
The movement of rivers, the processes of weathering and erosion, and tectonic activity create canyons.
River Canyons
The most familiar type of canyon is probably the river canyon. The water pressure of a river can cut deep into a river bed. Sediments from the river bed are carried downstream, creating a deep, narrow channel.
Rivers that lie at the bottom of deep canyons are known as entrenched rivers. They are entrenched because, unlike rivers in wide, flat flood plains, they do not meander and change their course.
Weathering and Erosion
Weathering and erosion also contribute to the formation of canyons. In winter, water seeps into cracks in the rock. This water freezes. As water freezes, it expands and turns into ice. Ice forces the cracks to become larger and larger, eroding bits of stone in the process. During brief, heavy rains, water rushes down the cracks, eroding even more rocks and stone. As more rocks crumble and fall, the canyon grows wider at the top than at the bottom.
When this process happens in soft rock, such as sandstone, it can lead to the development of slot canyons. Slot canyons are very narrow and deep. Sometimes, a slot canyon can be less than a meter (3 feet) wide, but hundreds of meters deep. Slot canyons can be dangerous. Their sides are usually very smooth and difficult to climb.
Tectonic Uplift
Canyons are also formed by tectonic activity. As tectonic plates beneath the Earth’s crust shift and collide, their movement can change the area’s landscape. Sometimes, tectonic activity causes an area of the Earth’s crust to rise higher than the surrounding land. This process is called tectonic uplift. Tectonic uplift can create plateaus and mountains. Rivers and glaciers that cut through these elevated areas of land create deep canyons.
Credit: National Geographic Society
Picture Credit : Google
