Aeolian landforms are produced mainly by wind. Rain may also assist their formation. They are most common in arid and semi-arid regions, especially deserts.
Erosional Landforms
Blowout or Deflation Hollow
Continuous wind action removes loose, fine-grained surface material. The resulting depression or hollow is called a blowout or deflation hollow.
Residual Rock Forms
Where hard and soft rocks occur together, wind preferentially erodes the softer rock. The resistant rock left behind may develop several forms:
- Mushroom rock or pedestal rock: a rock with a narrow, undercut base and a wider top. Sand-laden winds cause especially strong abrasion near ground level.
- Dreikanter: a wind-faceted stone, commonly with three faces. It is a type of ventifact (a rock shaped or polished by wind abrasion).
- Yardang: a long, streamlined ridge carved parallel to the prevailing wind in alternating resistant and weak material.
- Zeugen: tabular, ridge-like remnants created where a resistant cap protects softer rock beneath it.
- Demoiselles: isolated earth or rock pillars whose softer columns are protected by harder cap rocks.
Aeolian Erosional Plain or Pediplain
Long-term erosion can reduce extensive uplands to a broad, nearly level surface called an aeolian erosional plain or pediplain. The notes describe the following residual forms during progressive erosion:
- Plateau: an elevated, broad, flat-topped upland.
- Mesa: an isolated, broad, flat-topped remnant of a plateau, usually with steep sides.
- Butte: a smaller, steep-sided, flat-topped remnant formed by further erosion of a mesa.
- Pinnacle: a narrow pillar or spire produced by continued erosion.
- Inselberg: an isolated residual hill rising abruptly from a plain, often with a rounded top.
Depositional Landforms
Loess Plain
A loess plain is an extensive, nearly level surface formed by the accumulation of wind-blown, very fine sediment, predominantly silt.
Ripple Marks
Ripple marks are small, wave-like patterns produced by the deposition and movement of fine sediment by wind.
Desert Pavement
A desert pavement is a flat surface covered by closely packed pebbles and rock fragments. It commonly develops when wind removes the finer sediment and leaves the coarser material behind.
Dunes
Dunes are mounds or ridges of wind-deposited sediment, usually sand. Vegetation can stabilize some dunes. Their forms depend on wind direction, sediment supply, and vegetation.
| Dune type | Form and orientation |
|---|---|
| Barchan | Crescent-shaped dune with horns pointing downwind; the windward slope is gentle and the leeward slip face is steep. |
| Seif dune | Long, narrow dune resembling an extended arm of a crescent; generally associated with winds from more than one direction. |
| Parabolic dune | U-shaped dune whose arms point upwind, opposite to those of a barchan; vegetation commonly anchors the arms. The notes describe it as narrower and deeper than a barchan. |
| Transverse dune | Long ridge formed perpendicular to the prevailing wind direction. |
| Longitudinal dune | Long ridge formed approximately parallel to the prevailing wind direction. |