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Aeolian landforms, or Eolian landforms, are produced by either the erosion or depositive action of wind. These features may be built up from sand or snow, or eroded into rock, snow, or ice.
Aeolian are commonly observed in sandy deserts and on frozen lakes or sea ice and have been observed and studied around Earth and on other planets, including Mars and Pluto.
These impacts are separated in space by the saltation hop length of the traveling particles, which creates distinct areas of erosion and/or deposition. As time passes, the surface rises in areas with net deposition, and lowers in areas with net erosion, creating initial landforms. Larger aeolian landforms alter the surface wind field in patterns that promote their growth. They are thus very stable, once formed.
Deflation and abrasion are specific means of sediment transport than can also be attributed to aeolian processes. Deflation, which is named for the Latin word "deflare" meaning "to blow away", refers to the scattering and removal of rock particles by wind. Deflation occurs in deserts where diverse particles dominate the surface. In these arid zones, sand and rock fragments are blown by jets and streams of air which remove fine grained materials from the surface and leave behind a rocky desert. Abrasion is another mechanism of force exerted by the wind on surficial materials that is characterized by friction caused by moving particles scraping across a rock's surface and, as a result, continues to develop a land formation by removing further material.
Aeolian landforms are typically described in two categories: erosional and depositional.
| + Examples of Depositional Landforms !Landform !Description !Image | ||
| A dune is a large pile of wind-blown material, typically sand or snow. As the pile accumulates, its larger surface area increases the rate of deposition in a positive feedback loop until the dune collapses under its own weight. This process causes dunes to move in the direction of the wind over time. | ||
| Barchan | A type of dune that forms as a result of low sediment supply in regions where wind blows in one primary direction. This causes the dune to have a concave shape, with the tails facing downwind. Transverse dunes and are some alternative examples of the effect of unidirectional air flow on dune formation. | |
| Ripple marks | Ripple marks are small ridges of sediment that form due to wind or water blowing over loose sediment in either a current or wave pattern. Aeolian ripples result from high velocity winds which form fine, well-sorted grain particles into long, flat, asymmetrical ripples. | |
| Loess | Silt sized particles that can be carried by the wind over extensive distances, usually homogenous and highly porous. Generally, loess contains angular grains that are not well-polished due to the nature of their transport. | |
| Desert varnish | A coating that can be found on the surface of desert rocks that can only be explained by the presence of clay particles which have been transported by wind. The discoloration of the clays can most often be attributed to black manganese oxides and red iron oxides. |
| + Examples of Erosional Landforms !Landform !Description !Image | ||
| Deflation basin | A depression in the land that can be found in deserts due to the removal of particles by wind; it can also be referred to as a "blowout". | |
| Rock samples that demonstrate the erosion caused by aeolian processes over time. Erosional processes by wind can result in smoothing and polishing as well as the creation of grooves. | ||
| Formations that develop over thousands of years when the top of an outcrop is eroded by wind at a slower rate than the base of the outcrop. | ||
| Desert pavement (Lag deposit) | Rocks and sand grains that form a pavement due to deflation (winnowing). Wind removes sediment grains that it is capable of transporting away from an area, causing larger grains to accumulate on that surface. Lag deposits can also form due to removal of finer particles by water. | |
| A protruding rock that results from a streamlined carving from consolidated material by wind abrasion by dust and sand, and deflation. |
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