Canyons

A canyon is a deep, narrow valley with steep or near-vertical walls, typically carved by long-term erosion from a river or other flowing water through bedrock. Canyons form when a river cuts downward through rock while the land is uplifted, allowing headward erosion to continue and walls to steepen. The shape and size of a canyon depend on rock type, climate, and tectonics. In young, soft rock such as sandstone or shale, walls may remain steep with pronounced steps; in more resistant rock, canyons can be narrower and more dramatic. Arid regions often produce tall, vertical walls and deep channels due to limited debris and rapid downcutting during flood events. Slot canyons are especially narrow, serpentine passages formed by concentrated floodwaters that erode soft rock.

Common types include river canyons or gorges, box canyons with nearly rectangular cross-sections, and slot canyons. Erosion works alongside weathering, frost action, and sediment transport to sculpt terraces, alcoves, and arches.

Notable examples include the Grand Canyon in the United States, Fish River Canyon in Namibia, Colca Canyon in Peru, and Copper Canyon in Mexico. Canyons support diverse habitats and may host perennial streams, springs, and unique plant and animal communities. They are popular for recreation and scientific study but can pose hazards such as flash floods and falling rock.