Eolian Processes and Landforms

What are two factors that reduce wind erosion power?
The presence of vegetation and water in the surface soil.
What are 4 locations of drylands and what are they caused by?
Subropical Regions – stable descending air (high pressure cells)
Interior Continental Regions – no moisture bearing weather systems
Lee of Mountain Zones – rain shadow effects
Certain Western Coastlines – cold ocean current suppress sea surface evaporation
What are 2 types of eolian erosion?
Deflation and Abrasion
What is deflation?
The removal and lifting of individual loose particles
What is abrasion?
Grinding of rock surfaces with a sandblasting action by particles captured in the air
What are two landforms caused by deflation?
Blowout Depression (basin left when materials are removed) and Desert Pavement (thin layer of large particles)
What are two landforms caused by abrasion?
Ventifacts (aerodynamically shaped rocks) and Yardang (an elonged, streamlined ridged)
What are 3 types of eolian transportatin?
Suspension, Saltation, and Surface Creep
Winds cannot move particles larger than…
When does eolian deposition occur?
When wind speeds fall below the threshold to transport particles
What are two landforms formed by eolian deposition?
Loess Deposits and Dunes
What are the 5 steps of dune formation?
Sand Patch Initiation, Wind-Ripple Protodune, Streamlined Protodune, Protodune, and Dune with slipface
Describe dune migration.
Saltation of particles up the windward slope and over dune, sediment falls down slipface
What are the 4 broad classes of dunes?
Cresentic, Linear, Star, and Other
What determines the type of dune?
Wind strength and consistency, sand supply, and the amount of vegetative cover
Describe desertification.
The expansion of Earth’s desert lands and degradation of dry lands
What are the 2 causes of desertification?
Climate variation and unsustainable land use
What are 4 consequences of desertification?
Loss of soil productivity, crop failures, scarcity of fuel wood, and reduced availability of grazing land
Desert streams are…
What is a wash or arroyo?
Steep-sided ephemeral channels
What is a playa lake?
In arid regions and has no outlets, its internal drainage is evaporation
What is an alluvial fan?
Intermittent stream flow deposition

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