Canyon geography is very simple. A canyon is a huge valley, with tremendously deep, steep sides and perhaps a river flowing along the bottom. The term “Canyon” is derived from the Spanish word cañon, that implies “pipe” or “tube”. The word “gorge” is also most commonly used to refer to “canyon,” but a gorge is relatively steeper and narrower than a canyon almost always. That said gorges and canyons are almost similar except for steepness and narrowness.
How are Canyons Formed
The natural processes of weathering and erosion, the movement of rivers, and activity in tectonic creates canyons. Canyons are most commonly developed by erosion.
A canyon is a deep valley which is also narrow and cut by a river through rock. Canyons differ in size from narrow cuts to mega trenches. They consist of very steep sides and maybe thousands of feet deep. Smaller valleys of identical appearance are known as gorges. Over thousands of years a river's flowing water erodes or wears down rocks and soil to create a valley. The largest and most popular canyons have had slit through dry areas by swift streams sustained by rain or melting snow from wetter areas. The walls remain rough and steep since there is little rainfall or surface water to wear them off. An example is the Grand Canyon, in the U.S. state of Arizona.
Weathering and Erosion
Weathering and erosion also lead to the creation of canyons. In the winter season, water seeps into cracks in the rock and then this water. As this water freezes, it enlarges and converts into ice. Ice compels the cracks to get bigger and bigger, eroding bits of stone in the process. During short, heavy rainfalls, water gushes down the cracks, wearing off even more rocks and stone. As more rocks fragment and fall, the canyon grows wider at the top than at the bottom.
When this process takes place in soft rock, like the sandstone, it can result in the formation of the slot canyons. Slot canyons are observed to be very deep and narrow. At times, a slot canyon can even be less than a meter (3 feet) wide, but hundreds of meters deep. Slot canyons can be threatening since their sides are generally very smooth and difficult to climb.
Some canyons with hard, underlying rock may grow ledges and cliffs after crumbling their softer, surface rock. These ledges have the appearance of giant steps.
It is in fact quite amazing to know that sometimes an entire civilization can develop on and around these canyon ledges. Native US nations, such as the Sinagua and the Hopi created cliff dwellings. Cliff dwellings look like apartment-style shelters that accommodated hundreds of people. The shaded, lofted canyon ledges in Walnut Canyon and Canyon de Chelly, in Arizona, rendered protection from antagonist locales and the burning desert sun.
Hard-rock canyons open at one end are known as box canyons. The Navajo and Hopi people usually used box canyons as natural corrals for sheep and cattle. They simply established a gate on the open side of the box canyon, and closed when the animals were inside.
Limestone is a kind of hard rock which is most commonly found in canyons. Sometimes, limestone erodes and develops caves underneath the earth. As the ceilings of these caves crumble, canyons form. The Yorkshire Dales, a region in northern England, is an assemblage of canyons and river valleys developed by limestone cave collapses.
Grand Canyon Geology
The Grand Canyon is one of America’s treasure troves and a World Heritage Site of UNESCO. In the Grand Canyon, there are clear horizontal layers of different rocks that are themselves a telltale of when, where, and how they have been deposited, long before the canyon was even carved. The Law of Superposition implies that sediment is accumulated in layers in an order, with the youngest rocks on the top, while the oldest rocks on the bottom just the way sand piles up in an hourglass.