Most of dunes are migratory in nature and among all, Barchans are especially known to move ahead at rate of 25 to 250 meters a month. Hence barchans are said to be short-lived relative to or dunes.

Factors that affect attrition by wind are nature of region, velocity of wind and duration. It is not affected by sunlight.

The process of mechanical wearing where large-scale development of fracturing in confined rock masses is attributed to removal of overlying rock cover due to prolonged erosional work of or agencies is called unloading.

Sometimes due to deflation, huge depressions are created in deserts to such an extent that depression becomes so deep that it intersects with groundwater table. And it gets partially filled up with water and this is called an oasis.

Among granite and sandstones exposed to atmosphere simultaneously in same or adjoining areas having hot and humid climate, sandstone will resist wearing to a great extent because y are made up mainly of quartz(SiO₂) which is highly wearing resistant mineral.

The various process of chemical wearing operating on rocks and minerals under different atmospheric conditions may not always end up in formation of stable end products. Often y result in splitting of particles into smaller particles ? colloids- characterized by atoms with only partial satisfied electrical charges.

The rock masses under effect of unloading remain confined from sides but due to relief of pressure from above, y expand upwards; consequently joints develop in m parallel to uncovered surface dividing m into sheets.

Ions may be exchanged whereby some ions from water may enter into crystal lattice of mineral. This process of exchange of ions is called hydrolysis. It is a very common process of wearing of silicate minerals and is best explained with reference to wearing of mineral Orthoclase, Felspar.

The frost formed fragments are angular, sub angular, irregular in outline and remain spread over parent rock having flat surface or flat slopes. Spherical form or outline of rock doesn?t come into picture here.

A typical Loess is unconsolidated, unstratified, and porous accumulation of particles of size range 0.01-0.05 mm in diameter. This size fraction makes almost 40 percent of a particular loess deposit rest being made up of still finer clay grade material.