1. Earth Science Chapter 8 Section 2
Wind
Earth Science
Chapter 8
Section 2

2. Wind Erosion and Transport
A current of rapidly moving air can pick up and carry sediments
Can only carry small particles
Powerful agent of erosion
Particles move in different ways
Rolling motion along the ground
Suspension- carried in the air for a distance
Saltation- larger particles bounce along the ground
Limited precipitation leads to more wind erosion
Precipitation allows plants to grow
The plants keep the particles in place with their roots

3. Deflation Lowering of land surface Wind blows particles away
Dust Bowl caused by poor farming practices removed vegetation that held particles in place
Results in severe dust storms

4. Deflation Deflation Blowout
Shallow depressions where sediment has been blown away by wind
Vary in size from a few meters to hundreds of meters in diameter
Found in areas with sandy soil
Major problem in agricultural areas

5. Abrasion
Particles of sand rub against the surface of rocks or other material
Occurs in
Wind
Streams
Glaciers
Wind abrasion – particles are picked up and are blown against anything in its path

6. Abrasion Structures can be damaged by wind abrasion
Powerful erosional agent
Rocks can be pitted or grooved
Rocks can be polished
Erosion patterns determined by direction and force of the winds
Ventifacts- Rocks shaped by windblown sediments
Ventifact

7. Wind Deposition
Dunes
Sand particles that accumulate where an object blocks the forward motion of the wind
Pile of windblown sand is called a dune
Windward side- gentle slope
Leeward side- steep slope
Conditions that affect dune formation
Type and availability of sand
Amount of vegetation present
Wind direction and velocity
Windward side
Leeward side

8. Types of Dunes

9. Loess Wind carries fine particles, such as silt, for long distances
Thick windblown silt deposits
Source of silt deposits might have been glacial melting during ice age
Some of the most fertile soils
Contain abundant minerals and nutrients