Physical weathering processes can, over time, produce many and varied types of landforms. The landforms produced by physical weathering can be as dramatic as a lone butte in the desert or as subtle as a tree growing through a sidewalk.
Weathering is the natural process whereby rocks are broken down into smaller particles in place, more or less without movement. The two primary types of weathering are chemical and physical. In chemical weathering, the chemical nature of the weathered material changes, whereas in physical weathering, the chemical nature of the weathered material is unchanged.
Buttes and Mesas
Buttes and mesas are examples of landforms created by physical weathering. The two landforms actually are created by a similar process; the term "mesa" is used for large examples, and "butte" is used for smaller ones. Mesas and buttes form when the surface material of a hill or mountain is resistant to physical weathering but underlying materials are not, gradually creating an isolated, flat-topped promontory.
Natural Arches or Natural Bridges
Natural arches, or natural bridges, start life as a narrow ridge between two hills or mountains. Over time, a portion of the interior of the ridge is weathered away, while the bulk of the ridge resists weathering, resulting in an arch or bridge.