Canyon
A canyon is a valley walled by cliffs. Most canyons originate by a process of long-time erosion from a plateau level, with a stream gradually carving out its valley. 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 wetter areas because weathering has less of an effect in arid zones.
In the southwestern United States, canyons are important archeologically because of the many cliff-dwellings built there, largely by the Anasazi people.
The world's two largest canyons are the:
- Grand Canyon in Arizona, and the
- Copper Canyon in Chihuahua, Mexico
Other well-known canyon systems include:
The Blue Mountains west of Sydney in New South Wales, Australia contain many canyons carved into the sandstone rock.