Deposition-SedimentationDeposition-Sedimentationthe processes that release eroded materials causing sediments to settle into a new

location. A. Cause of Deposition:A. Cause of Deposition: 

1.  A Decrease wind or water current velocity.  

Mass Movements

Sand Dunes

Glacier

Moraine

Lake Bed

Beach

Flood Plain

Delta

B.B. Factors of deposition:Factors of deposition:

Particle Characteristics

1.      Density: High density sediments settle at a high rate.

2.     Shape: Round particles settle fast before flat sediments.

3.    Size: Larger particles settle faster than small particles.

Aluminum 2.7 g/ml

Lead 6.5 g/ml

C. C. Patterns of deposited sedimentsPatterns of deposited sediments

 1. Sorted Sediments:

Generally have the same size, shape, & consistency.

2.    Unsorted Sediments: Mixed sizes of sediments.

Glacial Till

Poorly Sorted

3. Vertical Sorting:

In sediments of mixed size, the largest particles will settle to the bottom first with smaller material on top.

4. Graded Beds:

Show alternating layers of vertical sorting caused by cyclic events like seasonal floods.

 

 5. Horizontal Sorting: Particles are sorted by size; as stream velocity decreases, the largest particles are deposited first followed by sands, silts, clay.

• Sediment burial with

compaction & cementation

resulting in lithification.

6. Wind Deposits:

Sediments which are sorted into tilted layers show cross bedding. The angle indicates the direction of current.

 

 Erosion-Depositional System:

Kinetic & Potential Energy exists within a stream. When the amount of material lost from erosion is the same gained by deposition a dynamic equilibrium is reached.

 Erosion-Depositional System A balance between erosion & deposition. (KE vs. PE)

1. Straight Channel

-Velocity Greatest In____________

-Erosion______________________

-Deposition____________________

2. Curved Channel

-Velocity Greatest _______________

-Erosion_______________________

-Deposition_____________________

Stream Velocity controls deposition

Largest particles drop out first as flow decreases.