A butte // is a conspicuous isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller than mesas, plateaus, and table landforms. In some regions, such as the north central and northwestern United States, the word is used for any hill. The word butte comes from a French word meaning "small hill"; its use is prevalent in the western United States, including the southwest, where "mesa" is also used. Because of their distinctive shapes, buttes are frequently landmarks in plains and mountainous areas.
In differentiating mesas and buttes, geographers use the rule that a mesa has a top wider than its height, while a butte's top is narrower. Three classic buttes are Scotts Bluff (actually a collection of five bluffs) in Nebraska, Crested Butte in Colorado, and Elephant Butte in New Mexico.
Among the well-known non-flat-topped buttes in the United States are Bear Butte, South Dakota, and Black Butte, Oregon. In many cases, buttes have been given other names that do not use the word butte, for example, Courthouse Rock, Nebraska. Also, some large hills that are technically not buttes have names using butte, an example of which is Kamiak Butte in Washington State.
Buttes are formed by erosion when hard caprock overlies a layer of less resistant rock that is eventually worn away. The hard rock thus resists erosion. The caprock provides protection for the less resistant rock below from wind abrasion which leaves it standing isolated. As the top is further eroded by abrasion and weathering the excess material that falls adds to the scree or talus slope around the base. On a much smaller scale, the same process forms hoodoos.
- ^ "Mesa and Butte". Science Clarified. 2008. Retrieved 2008-06-30.
- ^ Hill, R.T. 1890. A brief description of the Cretaceous rocks of Texas and their economic value. In: Dumble, E.T. (ed.), First Annual Report of the Geological Survey of Texas, 1889. Austin: State Printing Office, pp. 105-141.