1. True or False: The Earth’s surface has stayed the same for thousands of years

2. The Earth’s surface is always changing!
True or False: The Earth’s surface has stayed the same for thousands of years
False
The Earth’s surface is always changing!

7. Weathering and Erosion
Wind
Water
Ice
Gravity

8. The breakdown do the materials of Earth’s crust into smaller pieces.
Weathering
The breakdown do the materials of Earth’s crust into smaller pieces.
Weathering causes
soil formation

9. Water causes weathering
What evidence of weathering do you see in this picture?

10. Wind causes weathering
Why wasn’t this mass of land weathered away?
What evidence of weathering do you see in this picture?

11. Describe how ice causes weathering?

12. What evidence of erosion do you see in this picture?
The process by which water, ice, wind or gravity moves fragments of rock and soil.
What evidence of erosion do you see in this picture?

13. Erosion is Movement of Sediment!
This process, known as Erosion, is gradually wearing down the surface of the earth.
Erosion is the process by which weathered rock and soil (sediment) are moved  from one place to another.
Erosion carves the Earth's surface creating canyons, gorges, and even beaches.
What do you think has caused this rock to look this way?

14. The intensity of wind erosion is determined by:
As the wind blows it picks up small particles of sand/sediment and blasts large rocks with the abrasive particles, cutting and shaping the rock.
The intensity of wind erosion is determined by:
Sum (amount)
Speed
Slope
Surface
Abrasion: the sediment or sand blows into rock and causes pits in the rocks. (Not a mass movement)

15. Wind Erosion
Abrasion: the sediment or sand blows into rock and causes scratches and pits in the rocks. (Not a mass movement)
Abrasion

16. Wind erosion can cause deflation.
Deflation: erosion of land by wind; can lower the lands surface

17. You can determine the wind direction.
Wind Erosion
You can determine the wind direction.
You can also determine which direction the sand, or soil is migrating to.

18. Wind Erosion Creates sand dunes Greatest impact in deserts Removes
fertile topsoil

19. Water Causes Erosion runoff, rivers and, streams
Creates MOST of the changes
in the Earth's landscape!

20. Water causes Erosion
When rain falls to the Earth it can evaporate, sink into the ground, or flow over the land as Runoff.
When it flows over land, erosion occurs.
Runoff picks up pieces of rock and "runs" downhill cutting tiny grooves (called rills) into the land.
Rivers and streams are a
constant flow of runoff-
they constantly weather and erode!

21. Water causes Erosion
Sheet Flow: When water moves downhill in thin sheets.

22. Water causes Erosion
Rills: small channels cut in sediment
If these channels get .5 meters across they are now….
Gullies: larger channels at least .5 meters across.

23. Water causes Erosion
Gullies often lead into a stream.

24. Water causes Erosion
How much erosion takes place is determined by the:
Sum (amount)
Slope
Speed
Surface
Can you increase or decrease the 4 S's

25. Ice Causes Erosion
Glaciers occur when snow accumulates faster than it can melt, and a massive body of snow packs down and becomes thicker and thicker, heavier and heavier, until it has the weight and mass of rock, even though it is still frozen water.
Gravity then pulls this massive snow pack down to lower elevations, and as it travels, it shapes and scrapes, and fractures, and changes the surface of the earth.
How do glaciers form?

26. How do glaciers form?

27. Continental vs. Valley Glaciers
Continental Glaciers: Cover a whole continent; Arctic, Antarctic, Greenland,
Valley glaciers: located in high mountains and are smaller glaciers running down between mountains.

28. Ice Causes Erosion
Glaciers wear down the landscape; by picking up and carrying debris that moves across the land along with the ice.

29. Ice Causes Erosion
Glaciers can pick up and carry sediment that ranges in size from sand grains to boulders bigger than houses.
Moving like a conveyor belt and a bulldozer, a single glacier can move millions of tons of material!

30. Ice Causes Erosion
Glaciers form a U-Shaped Valley.

31. **Sum (Glaciers are massive!)
Ice Causes Erosion
How much erosion takes place is determined by the:
**Sum (Glaciers are massive!)
Slope
Speed
Surface

32. What is left behind when glaciers melt?
Ice Causes Erosion
Till: sediment deposition from melted glaciers; can range from clay to boulders.
What is left behind when glaciers melt?
We will discuss this more when we discuss deposition.

33. Gravity causes erosion
Creep, Slump, Landslides, Mudslides, and Avalanches.
Slower
Faster
These are examples of mass movement
(or called mass wasting)
landslide clip.mpeg

34. Gravity causes erosion
Creep: Due to freezing and thawing; slow moving mass movement down a slope. Page 325 in book

35. Gravity causes erosion
Example of Creep

36. Gravity causes erosion
slump: a mass of rock or sediment moves down hill leaving a curved scar. Page 324

37. Gravity causes erosion
rock slides: layers of rock break off and move to the bottom of a slope. Page 324

38. Gravity causes erosion
mud flow: a mass of wet sediment that flows downhill. Page 324

39. Gravity causes Erosion
How much erosion takes place is determined by the:
Sum
**Slope
Speed
**Surface

40. Effects of Erosion
Sediment removed: forms canyons, valleys and mountain cirques
A cirque ("serk") is a bowl-shaped rock valley on the side of a mountain, often with a glacier or permanent snowfield in it. (more below)

41. Effects of Erosion
Sediment deposition: forms deltas, sandbars, and sand dunes

42. Effects of Erosion
Sediment deposition: forms deltas, sandbars, and sand dunes

43. Plants CAN CAUSE weathering

44. Plants CAN PREVENT erosion

45. Deposition

46. Definition
Deposition- the process in which sediment is laid down in new locations
The end result of erosion

47. Together, Erosion and Deposition build new landforms.
Rock particles that are picked up and transported during erosion will ultimately be deposited somewhere else
Deposition is the process by which sediments (small particles of rock) are laid down in new locations.
Together, Erosion and Deposition build new landforms.
Deltas
Canyons
Meanders
Floodplains

48. Water Deposition Alluvial fan- fan shaped deposit of sediment on land
Usually form when a stream slows down and enters a flat plain
Delta- sediment from a stream deposited where a river enters a large body of water
Triangular shape
Sand Bar- Sand dropped when the tide comes in.

49. Alluvial fan and Delta

50. Delta
Where rivers meet the ocean is called the mouth of the river. Soil and dirt carried by these rivers is deposited at the mouth, and new land is formed. The new, soil-rich land is known as a Delta

51. Canyons are large valleys created by a river or stream.
This simple animation provides you with a visualization of how the Colorado River has "downcut" into the rock layers of the Grand Canyon.
How long it took to carve the Grand Canyon is debated by geologists.
Some estimates are between 6 and 8 million years, which is very recent by comparison.
Canyons are large valleys created by a river or stream.

52. This constant motion creates a series of S-shaped “loops”.
Meanders
Meandering streams wander side to side as they constantly seek out the lowest elevation.
This constant motion creates a series of S-shaped “loops”.

53. Meanders
Stream Velocity varies from one side to the other side of the “S”, resulting in erosion in some places and deposition of sediments in others.

54. Floodplains
Floodplains form along the banks of mid-order streams and larger rivers.
These are low-lying areas along the sides of a river channel that have regular times of heavy waterflow to cause the river to spill over and flood the land.

55. Glacial Deposition
As a glacier melts, it creates landforms by depositing its sediment load
Till-unsorted mixture of sediment containing fragments of various sizes
Moraine-mounds of sediment at the downhill end of the glacier and along its side
Long Island is a glacial moraine

56. Till and Moraines

57. What is left behind when glaciers melt?
Ice Causes Erosion
Till: sediment deposition from melted glaciers; can range from clay to boulders.
What is left behind when glaciers melt?

58. Ice Causes Erosion
Terminal moraine: The farthest the glacier went; can be a ridge 30 m. tall and 10 km wide; The Southern most part of the glacier began to melt quicker than the ice formed.
Moraines: landforms made from deposition of till.

59. Ice Causes Erosion
Ground Moraine: The till didn't build up a ridge because the glacier moving again. It still dropped some sediment off.

61. When melting occurs, streams carry and deposit sediment.
Ice Causes Erosion
outwash: sand and gravel deposits laid down by these melted glacier streams.
When melting occurs, streams carry and deposit sediment.

62. Wind Deposition Sand dunes- large deposits of sand dropped from wind
Sand dunes can move as the wind picks up sand from the back of the dune and blows it to the front

63. Other important vocabulary associated with wind erosion
Wind Deposition
Other important vocabulary associated with wind erosion
Loess: (LOOS)- accumulation of silt or fine sediment.
Loess was created by deposits of sediment and dust from glaciers.
Loess- extremely fertile.
Topsoils made up of loess are found in the central and northwestern parts of United States, in central and eastern Europe, and in eastern China.