Wind Erosion

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Wind Erosion
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Take-Away Points

• Wind erosion has little effect on solid rock
• Wind mostly moves loose material
• Sand dunes depend on strength and steadiness of
  wind and abundance of sand
• Windblown silt is called loess
• Loess is the raw material for many mollisols, the
  best agricultural soils

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Abrasion

• Ventifacts or Dreikanters
• Polishing,
• Undercutting
• Streamlining (Yardangs)
• On Mars, with billions of years of only wind
  erosion, wind has had much greater effects

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Ventifacts, Antarctica
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Dreikanter, Wisconsin
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Wind Abrasion, Independence Rock, Wyoming
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Wind (Aeolian) Landforms

• Little Power to Attack Solid Rock
• Most Effective in Moving Loose Material
• Mechanisms
• Suspension (Silt)
• Saltation (Sand)
• Rolling

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Wind (Aeolian) Landforms

• Deposition
• Dunes
• Loess
• Erosion
• Deflation Basins (Blowouts)
• Lag Deposits, Desert Pavement

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Sand Dunes
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Longitudinal Dunes, Colorado
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Longitudinal Dunes, Colorado
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Longitudinal and Transverse Dunes, Colorado
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Transverse Dunes, Sand Hills, Nebraska
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Beach Dunes, Michigan
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Barchans, Sand Hills, Nebraska
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Snow Barchans, Wisconsin
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Snow Barchans, Wisconsin
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Star Dune, Nevada
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Great Sand Dunes, Colorado
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Great Sand Dunes, Colorado
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Great Sand Dunes, Colorado
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Desert Pavement, California
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Lag Deposit, Minnesota
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Blowout, Wisconsin
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Loess

• Silt-sized
• Derived from Glacial Outwash in U.S.
• Found in U.S., E. Europe, China
• Parent material of worlds prime agricultural
  soils
• Available nutrients
• Fine size lots of surface area
• Cohesive good root support
• Porous retains water well
• No Rocks!!!!

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Loess, Wisconsin
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Loess in the U.S.
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Loess in Europe
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Loess in China
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Take-Away Points

• Wind has little effect on solid rock
• Wind mostly moves loose material
• Sand dunes depend on strength and steadiness of
  wind and abundance of sand
• Windblown silt is called loess
• Loess is the raw material for many mollisols, the
  best agricultural soils