Wind plays a crucial role in shaping landscapes, especially in arid and semi-arid regions of tropical and temperate zones. However, it has limited activity in cold deserts due to the presence of permanent ice sheets.

Aeolian Landforms

Aeolian landforms are surface features formed through the erosional or depositional action of wind. The term “Aeolian” is derived from Aeolus, the Greek god of wind.

Wind Erosion

Processes of Wind Erosion

1. Abrasion:
   • Sand grains carried by the wind act like sandpaper, rubbing against rock surfaces, which polishes, grooves, etches, and erodes them.
2. Deflation:
   • This refers to the removal of loose surface materials by the wind, leaving behind a lower-lying ground.
3. Attrition:
   • Particles transported by wind collide with each other, breaking into smaller fragments due to mechanical wear and tear.

Factors Influencing Wind Erosion

• Wind speed and intensity
• Quantity and characteristics of eroding agents like sand, dust, and pebbles
• Rock composition
• Vegetative cover
• Climatic factors such as humidity, rainfall, and temperature

Erosional Landforms Created by Wind

1. Deflation Basins (Blowouts/Desert Hollows):
   • Depressions formed by wind removing loose sands.
   • Example: Qattara Depression in the Western Egyptian Desert.

1. Inselbergs:
   • Isolated residual hills composed of resistant rock, standing above the surrounding terrain.
2. Pedestal Rocks (Mushroom Rocks):
   • Rocks with a broad upper section and a narrow base, sculpted by wind abrasion.
   • Known as Gara in the Sahara and Pilzfelsen in Germany.
3. Zeugens: 
   • Tabular rock masses resting on softer layers, shaped by wind erosion, often found in areas with significant temperature fluctuations.
4. Yardangs:
   • Sharp, sinuous ridges formed by differential wind erosion of alternating hard and soft rock layers.
5. Ventifacts:
   • Rocks with smooth, polished surfaces due to wind abrasion.
   • Dreikanter: A ventifact with three facets.
   • Einkanter: A ventifact with two facets.
6. Demoiselles:
   • Pillar-like rock formations with resistant rock at the top and softer rock at the base.
7. Wind Bridges and Windows:
   • Wind Windows: Holes created by wind abrasion.
   • Wind Bridges: Enlarged windows forming arch-like structures with intact roofs.

Wind Transportation and Deposition

Processes of Wind Transportation

1. Suspension:
   • Fine particles are carried in the air, forming dust clouds.
2. Saltation:
   • Medium-sized particles are moved by bouncing or leaping along the surface.
3. Creep:
   • Large sand grains roll or slide along the ground due to their size.

Wind Deposition

Deposition occurs when wind loses its energy, encounters obstacles, or slows down over oases.

• Sand Shadows: Accumulations of sand on either side of an obstacle.
• Sand Drifts: Sand accumulations between obstacles.

Depositional Landforms Created by Wind

1. Ripple Marks:
   • Small, wave-like ridges formed on sandy surfaces.

1. Sand Dunes:
   • Mounds of loose sand shaped by wind.
   • Types of Sand Dunes: 
     • Transverse Dunes: Aligned perpendicular to the wind.
     • Barchans: Crescent-shaped dunes that form when sand supply decreases.
     • Longitudinal Dunes (Seifs): Parallel to the wind, formed with limited sand supply.
     • Star Dunes: Central peaks with ridges radiating outward, formed by multidirectional winds.
     • Parabolic Dunes: U-shaped dunes stabilized by vegetation, resembling inverted barchans.
     • Nebkhas: Dunes formed around vegetation.
2. Loess:
   • Wind-deposited fine silt and dust.
   • Major deposits are found in northern China, the Great Plains of North America, Central Europe, and parts of Russia and Kazakhstan.