1. Erosion & DEPOSITION

2. Erosion & Deposition Terms
Erosion is the process that moves weathered rock sediments from one location to another
Deposition is the dropping of sediments.
Weathering is the breaking down of rock into smaller pieces

3. The following slides show examples of weathering:
Chemical & Mechanical

4. Wave action is when waves hit the rocks and pieces of rock break off
Wave action is when waves hit the rocks and pieces of rock break off. (Mechanical)

5. This rock is red because of the oxidation of iron in the sediment when the rock was being formed. (Chemical)

6. Root Pry
The tree is growing in the rock and soon the rock will break apart because of the tree roots.

7. This is a picture of the Half Dome
This is a picture of the Half Dome. The rock is peeling away from the mountain in layers just like an onion. This is exfoliation. (Mechanical)

8. Frost Action or ice wedging slowly breaks up this sedimentary rock into unusual shapes. (Mechanical)

9. Acid rain has eaten away this limestone statue. (Chemical)

10. There are many kinds of Erosion.
Here are a few:
Wave Action
Running Water
Landslides
Creep
Rock Fall
Mud Flow
Avalanche
Glaciers
Slump

11. Agents of Erosion Gravity Running Water Wind Glaciers
All agents of erosion carry sediments when they have energy of motion, and drop them when they lose their energy of motion.

12. Gravity Mass Movements Caused by Gravity:
Slumps, Creeps, Rockslides, & Mudflows

13. This is a picture of a landslide
This is a picture of a landslide. A landslide is a term used for all mass movements. Landslides leave un-stratified deposits.

14. Slumps A type of mass movement that takes place on steep slopes
loose materials slip down as one large mass    
doesn’t travel fast or far
curved scar is left
material underneath slumped

15. In this picture the land has slumped
into the road below.

16. Creep leaning things such as telephone pole, fence posts, or trees
sediments slowly creep down the hill
common where freezing and thawing occur (ice wedging)    
ground freezes, pushing up sediments, the ground thaws and the sediments fall downslope
less than a mm at a time

17. This is a diagram of creep
This is a diagram of creep. The hillside slowly slips over many years from temperature or water.

18. Rockslide
when large blocks or rock break loose from top of steep slopes and tumble to the bottom
happen in mountainous areas
 happen frequently after earthquakes and heavy rains but can occur without warning
“beware of falling rocks” signs
 pile of rocks at the bottom of a slope (talus slope)

19. Mudflows thick mixture of sediments and water
happen in relatively dry areas where thick layers of dry sediments form
heavy rains mix with sediments and form a thick,  pasty substance
lots of energy, can move anything in its path
( cars, houses, etc)
drops sediments and debris and forms cone- shaped deposits

20. Mudflows

21. Mudflows

22. This is a picture of an avalanche
This is a picture of an avalanche. It is similar to a landslide with ice and snow instead of rock.

23. How All Mass Movements are Similar
happen where there is a steep slope
all depend on gravity
occur frequently after heavy rains
erosion of sediments from the top of a slope to further down
makes slopes less steep

24. Erosion Caused by Running Water

25. Running Water
Water erodes more sediments than any other agent of erosion.
Water moves downslope.
When water loses energy, it deposits sediments.
Sediments are picked up from the bottoms and sides of streams.
Large sediments roll along the bottom; small sediments are picked up and carried by the water.
Sediments that are being carried knock even more sediments loose, which causes channels to widen and get deeper

26. Types of Water Erosion

27. Rill Erosion small stream forms during heavy rain
carries away plants and soil
leaves a scar
can lead to gully erosion

28. Gully Erosion . --carries away large amounts of soil
- rill channel gets broader and deeper

29. Sheet Erosion happens outside stream channel
water accumulates and eventually starts moving downslope, carrying soil with it
water soaks into soil or evaporates, leaving a sheet of soil

30. In this picture the running water eroded the sides of this canyon and created the V-shaped valleys.

31. Water
Deposition

32. Water Deposition
Some stream sediments travel great distances before being deposited
The Coastal Plain region of Virginia was formed from the deposition of sediments eroded from the Appalachian Mountains
Water has a lot of energy when flowing downslope- but it loses it when the ground becomes level

33. Types of Water Deposition
Alluvial Fans
-shaped like a triangle
-located on land at the bottom of slopes
Delta
-sediments are deposited when a channel runs into
a gulf, ocean, or lake
-triangle-shaped deposits
-Mississippi River Delta- largest in United States

34. Alluvial Fans

35. Alluvial Fans

36. Deltas

37. WIND EROSION
&
Wind Deposition

38. Wind Erosion Deflation- the moving of small sediments Abrasion
-compares to sandblasting
-grains bump into one another as they roll
along ground
-grains pit and polish rocks

39. These rocks have been blasted by wind and sand causing them to become rounded.
WIND ABRASION

40. Wind Deposition
2 Types:
Dunes & Loess

41. Dunes most common wind deposits
happen when sediments blow against an obstacle and pile up
form in deserts and beaches
dunes on Mars are evidence of wind

42. Dunes

43. Loess Deposits large deposits in United States and China
mid-western area has good farming because of these deposits
loess deposits of China form from sediments from Gobi and Ordos Deserts
fine as talcum powder

44. This is a picture of a glacier which carves out a U-shaped valley where it flows dragging rocks and boulders along the way.