Modes of transportation:
There are three modes of transportation of sedimentary particles:
- Traction
- Siltation
- Suspension
Traction:
Commonly, sediment grains larger than sand size are transported as part of the bed load in essentially continuous contact with the bed. This type of sediment transportation is called traction, which includes rolling of large or elongated grains, sliding of grains over past each other, and creeping, which is called movement of traction.
Siltation:
Siltation is a particular mode of transportation of fine sand. In siltation, particles bounce along the stream bed in a series of short, interrupted leaps. Sand grains may also move in a series of relatively short jumps or hops. Such a type of bed load transport is called siltation because the grains tend to move in intermittent contact with the bed.
Suspension:
Suspension occurs when the turbulence is greater than the settling velocity. Consequently, the upward/ vertical component of the turbulent motion equals/ exceeds the down-settling velocity of particles, and the grains go into the suspension while in transportation, the particles are in continuous processes of wear and sorting as to size and maturity (textural and mineralogical).
