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Agents of Erosion.

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Presentation on theme: "Agents of Erosion."— Presentation transcript:

1 Agents of Erosion

2 Erosion The process by which water, ice, wind or gravity moves fragments of rock and soil.

3 Water Erosion Rivers, streams, and runoff

4 Ice Erosion Glaciers

5 Wind Erosion

6 Mass Movements Landslides, mudslides, slump and creep
landslide clip.mpeg

7 Shoreline Erosion Erosion- the removal and transport of material by wind, water or ice Weathering- the breakdown of rock into smaller and smaller pieces by mechanical or chemical means Deposition- materials are dropped

8 Shoreline Shoreline- where land and a body of water meet.
Deposition- materials are dropped Waves are powerful agents of erosion and deposition

9 Waves Wind moves over the ocean= waves
The size of the wave depends on the size of the wind Waves may travel many kilometers Waves don’t travel alone They travel in groups called wave trains Breaking waves are known as surf The wave period is the time interval between breaking waves

10 Pounding Surf Energy is released when waves break
A wave can break rock or throw broken rock Waves wash into cracks of rock and break off boulders (huge rocks) or sand. New beaches can form!


12 Wave Deposits Waves can carry materials, including sand, rock fragments, and shells. Beach- any area of the shoreline made up of material deposited by waves Not all beaches are the same

13 Beaches are made of different types of material deposited by waves.
Compare the beaches… Beaches are made of different types of material deposited by waves.

14 Stormy seas= pebbles and larger rocks
Compare the beaches… Hawaii- eroded lava Pieces of seashell Stormy seas= pebbles and larger rocks

15 Wave Angles The way sand moves depends on the angle of the waves on the shore Waves come to shore at an angle Waves normally leave in an angle perpendicular to the shore Longshore current- water near and parallel to the shoreline

16 Wave Angles Sand Movement Longshore Current Wave Direction

17 Wave Angles- Diagram

18 Offshore Deposits Waves erode material from the shoreline and transports and deposits it Landforms are created in open water

19 Wave Erosion Waves strike (hit) and erode rock and wear away soil and rock How quickly sea cliffs erode depends on the hardness of the rock and the energy of waves

20 Wave Erosion

21 Wind Erosion Has wind ever blown your papers?
You already know how wind erosion works!

22 Take cover! Loose rock material Deserts Coastlines Plants
Plant roots anchor (keep down) sand and soil

23 Wind Erosion Wind moves material in different ways
Material is moved by saltation Saltation is the movement of sand-sized particles by skipping and bouncing in the direction of the wind

24 Particles roll forward or bounce in the air.
Saltation Particles roll forward or bounce in the air.


26 Deflation is the lifting and removal of sediment by wind

27 Deflation

28 Deflation




32 Deflation Before After

33 Deflation hollows

34 Abrasion Abrasion is the grinding and wearing down of rock surfaces by other rock or sand Strong winds Loose sand Soft rocks

35 Wind Deposited Material
All material carried by the wind is eventually deposited Dunes (common in deserts and along shores) Loess

36 Loess is finer than sand. It feels like powder.

37 Glacier Glacier- mass of moving ice 2 types Alpine Continental Glacier

38 Glacier Form in areas of snow on ground all year High elevations
Polar regions

39 Glacier Snow piles up snow packs crystals Giant ice mass
“Rivers of Ice”- begin to move (gravity)

40 Alpine Glaciers Forms in mountainous areas
Valley Glacier- form in valleys with streams flowing downhill Forms a U- shape

41 Continental Glacier Not all glaciers are “rivers of ice”
Can spread across entire continents Continental glaciers- continuous masses of ice

42 Continental Glacier Continental ice sheet- largest type of glacier*
Antarctica is almost completely covered by an ice sheet Contains 91% of glacial ice on planet ½ times the size of United States It is 4,000 m thick in some places; covers everything except highest mountain peaks

43 Ice Shelves Ice shelf- an area where ice is attached to the ice sheet but resting on open water Ross Ice Shelf- largest ice shelf Attached to ice sheet covering Antarctica

44 Ross Shelf

45 Ross Shelf

46 Icebergs Large pieces of ice that break off an ice shelf

47 Icebergs form by calving
Large pieces of ice that break off an ice shelf Icebergs form by calving

48 The Titanic Most of an iceberg is below the surface Hazard for ships

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