Landform is a distinctive feature of land on the surface of a planet, moon, or asteroid. Landforms on Earth include mountains, river valleys, sand dunes, volcanoes, and features carved by moving glaciers. Some are large, such as the massive volcanoes of the Hawaiian Islands. Other landforms are much smaller, such as talus slopes, piles of rock that form below crumbling cliffs.
A variety of different processes create landforms. Erosion (wearing away) of the land by running water can cut a river valley or canyon. Wind can also erode landforms over many years. Volcanoes form when magma (molten rock) erupts and is deposited on the surface. Moraines form when glaciers melt, depositing collected soil and rock in piles or ridges. In deserts and near the coast of a lake or ocean, wind often piles sand into dunes.
Some landforms reveal details of climate. Widespread glacial landforms, such as moraines, located far from existing glaciers indicate that the climate was once colder in those areas. Stable sand dunes covered in vegetation suggest that the area has become less dry or windy, enabling plants to take root.
Landforms are not unique to Earth. For example, the surfaces of Mercury and Earth’s moon are covered by craters formed by asteroid, comet, and meteorite impacts. On Earth, erosion eventually erases such craters. Mercury and the moon lack liquid water and an atmosphere to promote erosion. Their landforms thus do not erode as quickly.
For more information on various landforms, see the list of related articles.
