1. DEPOSITION
Deposition is the final step in the erosional-depositional system.
AGENTS OF EROSION BECOME AGENTS OF DEPOSITION

2. Deposition by Gravity mass movement – unsorted - no distinct layering
Ex. Rockfalls, mudflows, slump, soil creep

3. A. Deposition by Moving water:
streams deposit sediment when they slow down or decrease in volume resulting in sand bar-build up of sand size sediments in a stream or ocean at a point where the water slows

4. - oxbow lakes form, floodplains: stream overflows its banks
Mississippi delta as seen from space
- oxbow lakes form, floodplains: stream overflows its banks
- deltas: formed where river meets open water creating a fan shaped deposit
alluvial fans: sediment deposited by a stream onto open flat land
Delta

5. Beaches, sandbars, spits (connected to the mainland), and lagoons
B. Deposition by Oceans
- form new landforms
Beaches, sandbars, spits (connected to the mainland), and lagoons
Farewell Spit in New Zealand

6. C. Deposition by Wind: contains fine sediments
Dunes: windward vs leeward side
and
cross-bedding
Leeward side
Windward side

7. Cross bedding – arrangement of strata
(sedimentary rocks) inclined at an angle to the main layers.

8. D. Deposition by Glaciers:
Indirect – fluvio-glacial –sorted (meltwater streams sort sediments. Sorted then deposited in layers)
Direct – glacial drift/till –unsorted (glacial ice melts and sediments drop out in a jumble)

9. U-shaped valleys – erosion

10. What Factors Affect Deposition?
a. Particle Size: smaller particles settle out more slowly
time taken in minutes
Indirect Relationship
small large

11. b. Particle Shape: flat particles resist settling more than round particles10
time taken in
minutes Direct Relationship
round oval flat

12. c. Particle Density: Particles with greater density settle out faster10
time taken in
minutes Indirect Relationship
Density

13. d. Velocity: stream slows down – carrying power decreases – sizes carried and deposited also decreases (and vice versa).

14. SORTING: When particles are deposited the load can be sorted in different ways. A: Horizontal

15. Horizontal sorting
- When deposition occurs at the mouth of a stream, a process called horizontal sorting takes place.
- sediments that were once carried down the stream are arranged from largest to smallest.
- smaller particles settle more slowly than larger particles – due to pull of gravity  smaller particles stay in suspension longer.

16. B. Vertical Bedding (aka graded bedding)
decreasing grain size upward
through the bed indicating
deposition from a waning
(lessening) current.
One episode or layer of vertical
bedding

17. Youthful stream-fast moving, steep gradient, rapids
On the back of your notes read about Life of a Stream and add the notes. Take a look at the pictures to help you understand the concepts.: LIFE OF A STREAM
Youthful stream-fast moving, steep gradient, rapids
Mature stream-slows down, gradual decrease in gradient, flood plains begin to develop
Old Stream- very slow, large, carries much sediment, oxbow lakes, meanders, big flood plains
“Age” of Stream is due to landscapes it covers

19. Youthful Stream

20. Waterfalls-develop due to varying resistance in bedrock

21. Flood Plain-characterizes an old stream

22. Stream bed- notice varying sediment sizes