Wind Erosion

Take-Away Points 1.Wind erosion has little effect on solid rock 2.Wind mostly moves loose material 3.Sand dunes depend on strength and steadiness of wind and abundance of sand 4.Windblown silt is called loess 5.Loess is the raw material for many mollisols, the best agricultural soils

Abrasion Ventifacts or Dreikanters Polishing, Undercutting Streamlining (Yardangs) On Mars, with billions of years of only wind erosion, wind has had much greater effects 1.Wind erosion has little effect on solid rock

Ventifacts, Antarctica

Dreikanter, Wisconsin

Wind Abrasion, Independence Rock, Wyoming

Wind (Aeolian) Landforms Little Power to Attack Solid Rock Most Effective in Moving Loose Material Mechanisms Suspension (Silt) Saltation (Sand) Rolling 2. Wind mostly moves loose material

Wind (Aeolian) Landforms Deposition Dunes Loess Erosion Deflation Basins (Blowouts) Lag Deposits, Desert Pavement 2. Wind mostly moves loose material

Sand Dunes 3. Sand dunes depend on strength and steadiness of wind and abundance of sand

Longitudinal Dunes, Colorado

Longitudinal and Transverse Dunes, Colorado

Transverse Dunes, Sand Hills, Nebraska

Beach Dunes, Michigan

Barchans, Sand Hills, Nebraska

Snow Barchans, Wisconsin

Star Dune, Nevada

Great Sand Dunes, Colorado

Desert Pavement, California

Lag Deposit, Minnesota

Blowout, Wisconsin

Loess Silt-sized Derived from Glacial Outwash in U.S. Found in U.S., E. Europe, China Parent material of world’s prime agricultural soils –Available nutrients –Fine size – lots of surface area –Cohesive – good root support –Porous – retains water well –No Rocks!!!! 4. Windblown silt is called loess

Loess, Wisconsin

Loess in the U.S. Loess is the raw material for many mollisols, the best agricultural soils

Loess in Europe 5. Loess is the raw material for many mollisols, the best agricultural soils

Loess in China 5. Loess is the raw material for many mollisols, the best agricultural soils

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