Transportation processes - Wind
Wind transports rubble near the surface by ‘saltation’. Saltation refers to short jumps of grains displaced from the surface caused by the force of wind. As the grains fall back to the surface they may disturb other grains that then get carried by wind until they collide with ground. This then leads to the process continuing on, leading to dislodge of other particles.
Deflation
Deflation is the lowering of the land surface due to removal of fine-grained particles by the wind. Deflation concentrates the rougher grained particles at the surface, eventually resulting in a surface composed only of the coarser grained remains that cannot be transported by the wind. This type of surface created is called a desert pavement.
Dunes - Linear
Linear Dunes are long straight dunes that form in areas with a limited sand supply and converging wind directions.
Dunes - Parabolic
Parabolic are "U" shaped dunes with an open end facing upwind. They are usually stabilized by vegetation, and occur where there is abundant vegetation, a constant wind direction, and an abundant sand supply. They are common in coastal areas.
Sand Dunes
Sand dunes form when there is
1. a large supply of sand
2. a steady wind
3. Some kind of obstacle such as vegetation, rocks, or fences, to trap some of the sand.
Sand dunes form when moving air slows down on the downwind side of an obstacle. The sand grains drop out and form a mound that becomes a dune.
1. a large supply of sand
2. a steady wind
3. Some kind of obstacle such as vegetation, rocks, or fences, to trap some of the sand.
Sand dunes form when moving air slows down on the downwind side of an obstacle. The sand grains drop out and form a mound that becomes a dune.