Wind Erosion

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay

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Wind Erosion

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

Abrasion

• Ventifacts or Dreikanters
• Polishing,
• Undercutting
• Streamlining (Yardangs)

Transportation

• Desert Pavement
• Deflation Hollows
• Roots Exposed
• Large - Quattara Basin, Egypt

Sand Dunes

• Determined by
  • Sand Supply
  • Winds
• Barchan - Little Sand
• Transverse - Lots of Sand
• Longitudinal - Steady Winds
• Parabolic - Transitional between transverse and longitudinal
• Star - Several Wind Directions

Loess

• Silt-sized
• Derived from Glacial Outwash in U.S.
• Found in U.S., E. Europe, China

  Loess in the U.S. is derived from glacial outwash. The loess was blown directly from glacial deposits in the Rockies, and also carried by rivers to be blown off the flood plains. The loess in western Wisconsin is thick. It is virtually absent in eastern Wisconsin partly because the loess blanket naturally tapers, buit also because most of eastern Wisconisn was still ice-covered at the time, so loess was intermingled with other materials.

  Loess in Europe is similarly derived from glacial outwash.

  Loess in China is indirectly derived from glacial outwash, which is carried into the desert lowlands by streams. Wind transports loess from the deserts, and the loess is in turn redeposited by the rivers.

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Created 21 May 1997, Last Update 3 November 1999