Erosion is a geological process pertaining to the downslope movement of rock particles through the action of gravity. These fragmented materials are then transported from one place to another by environmental agents, such as water, ice and wind.
Erosion is an important factor in landform development. Erosion that occurs near running water, such as river banks, results in the creation of valleys. This natural process is exemplified in the formation of the Grand Canyon in Arizona, which was continuously washed away by the Colorado River throughout time.
Erosion by wind often results in sand dune formation in desert regions, such as in China's Gobi Desert. In the United States, the Arches National Park in Utah is brought about by wind erosion. Glacial erosion, meanwhile, is responsible for the formation of the lowest point of the Finger Lakes in New York.