1. Shaping the Land
Earth’s Changing Surface

2. Erosion, Sediments and Deposition
Erosion – the process of moving weathered rock and soil from one place to another.
Sediment – the material MOVED by erosion.
Deposition – the dropping (depositing) of sediments as energy of motion decreases.

3. Weathering, Erosion and Deposition CYCLE
What is a CYCLE?
A process that repeats itself.
3 processes are constantly working on earth.
As one area on earth is WEATHERED (broken down), ERODED (carried away), sediments are DEPOSITED in another area (built up!)
Constantly changing the shape of the Earth.

4. Agents of Erosion
Agents (the thing) that erodes the surface of the earth:
Gravity
Running Water
Wind
Ice
Waves
Which “agent” is the most effective at erosion?
RUNNING WATER – is the major agent shaping the surface of the Earth. Found everywhere.

5. Agent #1 - Gravity
Gravity – the force that moves rock and other materials DOWNHILL
Causes MASS MOVEMENTS – processes that move sediments downhill. Some types are fast, others are slow.

6. Mass Movements
4 types
Rockslides/Landslides
Mudslides
Slump
Creep

7. Rockslides/Landslides
Most destructive
Rock and soil slide QUICKLY down a slope
Common in mountainous areas, usually occur after heavy rains or earthquakes.
Forms TALUS SLOPES at bottom (pile of rocks)

8. Talus slope from Landslide

9. Rock pile from rockslide
Notice the scale – the size of the men to the size of the rocks

10. Mudslides
Water with sediments, gravity causes the mixture to slide downhill.
Occurs in DRY AREAS AFTER heavy rains.
Enough energy and mass to destroy things in path (houses, etc.)
Deposits at bottom of hill are usually cone-shaped.
                                 

11. Mudslide – after heavy rain

12. Mudslide

13. SLUMP Rock and soil suddenly slips down a slope. Does not travel far.
Moves in ONE LARGE MASS! (different than landslide/rockslide)
Looks as if someone pulled the bottom out!

14. Slump

15. Slump

16. CREEP Sediments slowly move downhill
Often caused by freeze-thaw action.
Happens over several years.
Evidence of creep by leaning utility poles, fences, tree trunks.

17. Creep – Look at the trees

19. Creep

20. CREEP in a Cemetery

21. AGENT #2 – Water The most influential force in erosion is water.
Water’s ability to move materials from one location to another, along with the fact that it is found everywhere along the surface of the earth, makes it a superb tool for erosion.

22. Water Erosion Water erosion begins with a splash of rain
As water from rain moves over land it carries pieces of sediment with it – this water is called RUNOFF!
Water ALWAYS flows from higher to lower elevations, i.e., it flows downhill!

23. Erosion by Rivers Rivers create:
Valleys and Canyons
Waterfalls
Floodplains
Meanders
Oxbow Lakes
Rivers often START on steep mountain slopes, pick up sediments from mass movements or from runoff.

24. Erosion by Rivers Valleys (V-Shaped Valleys)
Near the source of a river, fast-flowing and has a narrow straight course.
Sediments along the side get carried away quickly
Creates a deep, V-shaped valley

26. Erosion by Rivers CANYONS
A narrow, deep, rocky, and steep-walled valley carved by a swift-moving river.
Its depth may be considerably greater than its width.

27. Grand Canyon – formed by water
The Colorado River has eroded away the layers of sedimentary rock and formed the Grand Canyon.

28. Grand Canyon Formation
Grand Canyon Flyover

29. Waterfalls Waterfalls
When water meets hard rock that is not easily worn away, it continues to flow downstream to softer rock and wears the soft rock away!

30. Waterfalls
DRAW THIS!

31. Paterson Falls, Paterson NJ

32. Waterfall in Tinton Falls, NJ
The “falls” are located near the center of town in Tinton Falls, near the mills and MJ’s pizza.

33. Erosion by Rivers Flood plain Flat land next to a river or a stream
As rivers flow along less steep land, they spread out
During a flood, this is where all of the excess water goes!

34. FLOOD Plain – Draw this!

35. Erosion by Rivers
Meander
A loop—like bend in the course of a river
Sediments get pick up and dropped off
The older a river is, the more erosion has occurred and the more and more curved it becomes

36. River Meander – DRAW THIS!!

37. River Meander – Mississippi river

38. Glen canyon River Meander
Glen Canyon is in Utah and Arizona

39. Oxbow Lake
Oxbow Lake
A meander that has been cut off from the river because of sediments
Draw this!

40. Oxbow lake

41. Oxbow lake - borneo

42. Deposition by Rivers
Moving water carries sediments and when the water slows down the sediments drop out and get “deposited”
Deposition BUILDS up new landforms
3 types:
Alluvial fans
Deltas
Flood plains

43. Alluvial Fans
When a fast moving stream slows down (i.e., when it comes out of a mountain range)
Deposits sediments in the shape of a wide fan

44. Alluvial fan – death valley ca

45. Alluvial fan – draw an example

46. DELTAS The end of a river; when it flows into an ocean or a lake
The water is no longer moving downhill, slows down and sediment fall to the bottom.
The landform that is built up from these deposits is a DELTA

47. Mississippi delta by satellite
A and C are islands formed by the river
B is the Mississippi River deposits and D is the Mississippi Sound

49. Nile river delta

50. FLOOD PLAINS
Heavy rains or melting snow can cause rivers to rise over the edges of its bank and spread out over its “flood plain”
As the water recedes, sediments drop out
Makes fertile soil; good for crops.

51. River flooding into flood plain

52. Sediment deposits in pennsylvania

53. River deposits after flooding in australia

54. GLACIERS Any large mass of ice that moves over land.
Valley glaciers – long, narrow snow and ice that build up in valleys of mountains
Continental glacier – a glacier that covers much of a continent or large island. Larger than valley glaciers
Form when snow build up year after year, pressure of the snow compresses the snow at the bottom into ice, and eventually gravity begin to pull it down the mountain.

55. Valley Glacier

56. Valley Glacier - Canada
Near Banff, Canada

57. Continental Glacier - Antarctica

58. Glacial Landforms

59. Corbet's Couloir Hanging valleys
Couloir and Hanging Valleys

60. MINI LAB How do glaciers change the land?
Hold the ice with paper towels. Rub the ice, sand side down, over a bar of soap.
What happens to the surface of the soap?
Record your observations, wipe up your desks.
Return the soap to the paper plates.

61. GLACIAL EROSION Move slowly (centimeters to meters daily)
Creates U-shaped valleys!

62. U-Shaped Valley – Draw a picture
Valleys carved by glaciers – notice the U shape rather than an V shape!
U-shaped valleys found in Alaska

63. Greenland and a u-shaped valley

64. Glacial Forces of Erosion
Major force of erosion
Plucking
Picking up of rocks since they froze to the bottom of the glaciers
Abrasion
Dragging the rocks frozen to the bottom of the glacier causes:
Striations – gauging and scratching of the bedrock

65. Plucking and Abrasion

66. Glacial striations
Striations in Canada

67. Glacial Striations
Rock in Central Park, New York

68. GLACIAL DEPOSITION
As a glacier retreats (or melts), it drops the sediments that it “plucked” up along the way – called “till”
Till – the mixture of sediments that a glacier drops on the surface
Moraine – the till deposited by the edges of a glacier
Terminal moraine – the till left behind at the furthest location the glacier traveled.
Long Island, New York is a terminal moraine.

69. Glacial Till and Moraines
Terminal Moraine, Lateral Moraines and Till

70. Lateral Moraines

71. Terminal Moraine in Alaska

72. GLACIAL DEPOSITION Kettle Lakes
Glaciers drop chunks of ice in the till
Ice melts, fills the area with water – called a kettle – if the water stays it forms a lake
Northwest NJ, Stokes State Park – hundreds of Kettle lakes and ponds
The Great Lakes are kettle lakes

73. Kettle lake formation – draw this!

74. Kettle lakes in Canada

75. Kettle Holes in stokes state park and the Great Lakes

76. Glacial Deposition Erratic
Rocks dropped by glaciers – very different in shape and type from “native” rocks
Some are quite large!

77. Glacial Erratic – central Park NY

78. Tripod Rock, Boonton NJ
Tripod Rock on Pyramid Mountain

79. WIND EROSION Wind, by itself is the weakest agent of erosion
In areas where few plants survive to hold soil in place (i.e., deserts, beaches) wind is powerful.
The main way that wind causes erosion is by DEFLATION and ABRASION!

80. WIND EROSION - DEFLATION
Deflation – the process by which wind removes surface materials. Lifts dirt, blows it around, and drops it off somewhere else.
The stronger the wind, the larger the particle it can pick up and move.
All particles picked up by wind will eventually fall back down – may form DUNES.

81. SAND DUNES
Created on beaches and in deserts – when sand is dropped by wind – usually when the wind hits an obstacle.
Can be long and parallel, can be U-shaped, can be small or large and move over time.
Sand dunes constantly shift location with the wind, plants help to keep the dunes in place.

82. U-Shaped (or Parabolic) Dune
Formed in a U Shapes from the wind due to little vegetation!

83. Beach dunes – Sandy Hook

84. Long and Parallel sand dunes
Also called TRANSVERSE sand dune! The wind blows perpendicular to the dune!

85. WAVE EROSION Wearing away of rocks or beaches due to wave action
Creates:
Sea Caves Beach erosion
Sea Cliffs Spits
Sea Stacks Barrier Islands
Arches
Coves

86. Wave Erosion

87. Wave Erosion - Coves