Download Agents of Erosion and Deposition

Intro
Deposition is the process by which rocks, sand and sediment are deposited by the
forces of erosion. Deposition is intimately tied to the processes of weathering and
erosion. First, rocks are broken down into small pieces. This process is known as
"weathering." Small pieces of dirt and sand are then picked up by forces of nature
in a process known as "erosion." When those sediments are left in a new place,
this is called "deposition."
Agents of Erosion and Deposition
The natural forces that move--or erode--sediments are the same ones that deposit them. There are four primary
agents of deposition. Glaciers pick up rocks and deposit them as they move.
Gravity acts as an agent of deposition when rocks fall or tumble downhill. Wind
picks up lighter forms of sediment, such as dust and sand, and deposits them as
it slows. Water is an agent of deposition in many forms, including the actions of
streams, runoff from rainwater that is not absorbed into the ground, and the
actions of ocean waves.
Factors Affecting Deposition
Several factors affect when and where deposition occurs once sediment
has been eroded. The velocity--or speed--of wind and water is of primary
importance; as wind or water slows, heavier sediments drop out and are
deposited. The density and size of sediment also affects the rate of
deposition; because larger and denser particles tend to be heavier, they
are deposited by wind and water before smaller, less dense particles. The
shape of sediment also affects deposition rates; round pieces of sediment
settle more quickly than flat pieces.
Landforms Produced by Deposition
The process of deposition creates many types of landforms on earth. Rockslides on
hills and mountains are created as gravity erodes and deposits rocks. In the desert,
the deposition patterns of the wind creates sand dunes. Streams create deltas
when they deposit sand and sediment at their mouths, where the water slows to
meet the ocean. The waves of the ocean create beaches as they deposit sand over
time.