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AEOLIAN TRANSPORTATION
from AEOLIAN - AADRL
by Salim Hilles
The Process Behind The Formation Of Dunes
01. SUSPENSION
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Particle Size: <0.1 mm
Suspension defines the transportation of sand particles ranging from sizes smaller than 0.1 mm. As these particles are small and light, the wind carries them for very long distances; from hundreds to thousands of kilometers.
This process describes the formations of dunes, and how the wind as a power force that shapes the desert and its overall environment. The dynamic, ever-changing formation of the desert can be mainly attributed by the wind. It is mainly a description of different classifications of particles and how the wind affect each of them differently to create a dune.
Aeolian Deposition
As the wind loses energy, it deposits these sand particles it has been carrying. This happens when either the wind loses its energy over a period of time or when sand particles collide with objects such as sedimentary rocks, causing the particles to accumulate over time. As the object gets larger, more material is deposited. Particles classified under the surface creep process begin this accumulation as they are closer to the ground, making obstacle collisions more frequent. Particles classified under the saltation processes contribute to this accumulation by colliding by either an obstacle it has collide with or with the pile of sand that has already accumulated after a period of time. Lastly, particles classified under the suspension process are only affected after they collide with a larger body of sand that has accumulated. With this process, dunes are formed; shaped by the wind.
02.SALTATION
Particle Size: 0.1 mm - 1.00 mm
Saltation defines the transportation of sand particles ranging from sizes between 0.1 mm up to 1.00 mm. As the particles are heavier, the wind carries them tens to a few hundred kilometres. They often bounce up to 1.5 meters in height. This explains why rock formations eroded faster from the bottom.
03.SURFACE CREEP
Particle Size: >1.00mm
Surface Creep defines the transportation of sand particles ranging from sizes larger than 1.00 mm. As the particles are heavier, the wind is unable to carry them, instead the wind pushes and rolls them along the ground plane. This process leads to another process called Aeolian Deposition, which further explains how dunes are formed.
