Transported soil is weathered soil deposits that are transported from one place to another by natural agents like wind, water, and glaciers. Based on the means of transportation, there are wind-transported soils, water-deposited soil and glacier-deposited soils.
A brief description of different transported soil deposits and their features are explained in this article.
1. Water-Deposited Soils
Water forms one of the major transporters of soil deposits. The size of the soil deposits carried by the water depends on the velocity of the moving water. The water with a considerable velocity can erode the hills and deposit the same in the valleys.
High swift water can carry a large amount of soil (both coarse and fine) either by suspension or through rolling. As the velocity decreases the coarser particles get deposited. Further decrease in the velocity makes finer soils to deposit. When the velocity almost moves to zero, a delta is formed at the receiving body of still water as shown in figure-1 below.
The soils carried and deposited by water are called alluvial deposits. Those deposits made in the lake are called lacustrine deposits. When these deposits are carried to the ocean or sea, it is called as marine deposits.
2. Wind-Transported Soils
The soil deposited by wind is called as aeolian deposits. The size of particles transported is dependent on the velocity of the wind. In arid regions and leeward side of sea, large sand dunes are formed due to wind.
A type of silt deposited by wind is loess. This soil has low density and is highly compressible. This type of soil lacks sufficient bearing capacity.
3. Glacier-Deposited Soils
Large glaciers during their movement, carry soils of various sizes to huge boulders. The soil gets mixed up with the glacier and gets transported to large distances.
The deposits made by glaciers either directly or indirectly are known as drifts. When soil deposits are formed by the melting of glaciers, it is called as till.
The deposits formed by glaciers are called as glaciofluvial. These soil deposits are made by melting water and finally possess stratification. These deposits of glacial till posses high shear strength and can be compacted to sufficient dry density.
4. Gravity-Deposited Soils
Soils can be transported and deposited by the action of gravity. The movement, in this case, might be a very small distance. For example, the movement from a steep slope under the action of gravitational force.
Talus is a type of colluvial soils that are deposited by gravitational force. It consists of good coarse-grained particles and rock pieces which are highly demanded in engineering works.
5. Soil Transported by Combined Agents
Soils can also be transported by two or more agents. For example, soil deposited by wind can fall through a slope due to gravity. This deposit can be picked up by water and get deposited somewhere else.
Also Read: Formation of Soils