The earth’s crust is constantly undergoing geological changes caused by internal and external forces which create new landforms. The external forces are working vigorously to wear away the surface and the interaction of these forces gives rise to present day landforms. The process is carried out in four phases-

• Weathering- the gradual disintegration of rocks by atmosphere oe Weather forces into smaller particles.
• Erosion- the active wearing away of earth’s surface by moving agents like running water, ice, wind.
• Transportation- the removal of the eroded debris to a new position.
• Depostion- the dumping of debris in certain places of surface, where it may accumulate to form new rocks.

Aeolian landforms are produced by wind erosion and deposition process. This process produce a number of distinctive features-

• Mushroom rocks- these have been eroded, pitted, etched, grooved and polished by ice crystals or sand carried by wind.
• Yardangs- these are ridge separated parallel troughs carved into softer rock that runs in the direction of wind.
• Zeugen- these are the tabular masses which have a layer of soft rock laying beneath a surface of more resistant rock.