1. Wind Erosion
Glencoe Earth Science

2. Wind Erosion & Transport
Current of rapidly moving air can carry sediment
Move sand on the ground in a rolling motion
Suspension
Strong winds can cause small particles to stay airborne
Saltation
Bouncing motion of larger particles
Occur in areas of little vegetative cover
Deserts
Semiarid areas
Seashores
lakeshores

3. Deflation Lowering of land surface Desert pavement
Results from winds removal of surface particles
Desert pavement
Coarse surface left behind by removal of finer surface by wind erosion

4. Deflation Dust Bowl Great Plains 1930’s Severe drought
Poor agricultural practices
Removal of natural vegetation
Strong winds led to severe dust storms
Present time- thousands shallow depressions
Deflation blowouts

5. Abrasion
Particles such as sand rub against the surface of rocks or other materials
Due to erosion by wind, water, and glaciers
Wears away rocks
Pitted & grooved to smooth surfaces
Ventifacts
Rocks shaped by windblown sediments
Arches & pillars

6. Wind Deposition Occurs when wind velocity decreases
Windblown sand deposits on the ground
Forms a dune
Dunes
Windward side – side from which the wind blows
Gentler slope
Leeward side – side protects from wind
Steeper slope

7. Dunes Factors in dune Formations that determines its shape
Availability of sand
Wind velocity
Wind direction
Amount of vegetation present

8. Dune Migration
Prevailing wind continues to move sand from the windward side to the leeward side
Dune moves slowly over time

9. Types of Dunes Barchan Dunes Form solitary, crescent shapes
Form from small amount of sand
Minimal or no vegetation
Form in flat areas of constant wind direction
Crests point downwind
Reach max size of 30m

10. Types of Dunes Transverse Dunes Form series of ridge shapes
Form from large amount of sand
Minimal or no vegetation
Form in ridges that are perpendicular to the direction of the strong wind
Reach max size of 25m

11. Types of Dunes Parabolic Dunes Form u-shapes
Form from large amount of sand
Minimal vegetation
Form in humid areas with moderate winds
Crests point upwind
Reach max size of 30m

12. Types of Dunes Longitudinal Dunes Form series of ridge shapes
Form from small or large amount of sand
Minimal or no vegetation
Form parallel to variable wind direction
Reach max height of 300m

13. Types of Dunes

14. Loess Thick, windblown silt deposits
Accumulated as a result of thousands of years of dust storms