Wind erodes the Earth's surface by deflation, the removal of loose, fine-grained particles by the turbulent eddy action of the wind, and by abrasion, the wearing down of surfaces by the grinding action and sand blasting of windborne particles.
 The sand and rock of China's Turpan Depression resemble closely those in the view of the Martian surface shown in "Types of Deserts." |
 The arrow points to shiny black desert varnish on these rocks of Egypt's southwest desert (photograph by Carol Breed). |
A dark, shiny stain, called desert varnish or rock varnish, is often found on surfaces of some desert rocks that have been exposed at the surface for a long period of time. Manganese, iron oxides, hydroxides, and clay minerals form most varnishes and provide the shine.
Deflation basins, called blowouts, are hollows formed by the removal of particles by wind. Blowouts are generally small, but may be up to several kilometers in diameter.
Wind-driven grains abrade landforms. Grinding by particles carried in the wind creates grooves or small depressions. Ventifacts are rocks which have been cut, and sometimes polished, by the abrasive action of wind.
Sculpted landforms, called yardangs, are up
to tens of meters high and kilometers long and are forms that have been
streamlined by desert winds. The famous sphinx at Giza in Egypt may be a
modified yardang.
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| A | B |
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| C |
Yardangs of the Lut desert of Iran. View from Landsat (A), from high-altitude photograph (B), and from low-altitude photograph (C). These yardangs are among the largest on Earth, with almost 100 meters of relief (low-altitude photograph by J.T. Daniels, aerial photograph by U.S. Air Force). |
Information provided by A . S . Walker
http://pubs.usgs.gov