1. Erosion and Deposition

2. Erosion
Sediment
-natural forces move rock/soil from one place to another.
-gravity, water, wind, glaciers, waves are causes
-material moved by erosion

3. Deposition
-when erosion lays down sediments
-works with weathering & erosion
-involved in wear down and build up of Earth’s surface
-never ending cycle

4. Water Erosion Runoff & Erosion Runoff
-major agent of erosion: moving water
-all remaining water on Earth’s surface
-may cause sheet erosion (thin layer over land)

5. Rills
Gullies
-tiny grooves in the soil
-large groove, or channel, in soil that carries runoff
-only flow after it rains
-may dry up

6. Streams
Rivers
-channel where water constantly flows down a slope
-rarely dries up
-also called creeks or brooks
-a large stream

7. Amount of runoff
-depends on 5 factors:
1. amount of rain in an area
2. vegetation: grasses, shrubs, trees reduce runoff
3. type of soil
4. shape of the land: steep land has more runoff than flatter
5. how people use the land
-more runoff = more erosion

8. River Systems
Tributary
Drainage Basin
-stream that flows into a larger stream
-ex. small creek that flows into a large river is a tributary to that river
-land area where a river and its tributaries collect water

9. Divide
Erosion by Rivers
-high ground between two drainage basins
-ex. Continental Divide
-rivers create: valleys, waterfalls, flood plains, meanders, & oxbow lakes

10. V-Shaped Valleys
Waterfalls
-form when rivers erode along steep slopes
-occurs when river meets an area of rock that is hard & erodes slowly

12. Flood plains
Meanders
Oxbow lake
-flat, wide area of land along a river
-looplike bend in a river (snake-like)
-meander that has been cut off from a river (u-shape)
-may form when a river floods

15. Deposits by Rivers
Alluvial Fan
-deposition creates: alluvial fans & deltas
-can also add soil to a river’s flood plain
-wide, sloping deposit of sediment formed where a stream leaves a mountain range
-shaped like a fan

17. Delta
-landform made of sediment deposited where a river flows into an ocean or lake

18. Groundwater Erosion & Deposition
-water soaks into ground when it rains
-underground water
-affects the shape of the land
-causes erosion through chemical weathering
-combines with carbon dioxide to form a weak acid = carbonic acid
-weathers limestone
-forms deposits from roof/floor of caves

19. Stalactite
Stalagmite
Karst Topography
-deposit on roof of cave
-cone-shaped deposit on floor of cave
-landscape where limestone is near the surface
-characterized by caverns, sinkholes, and valleys

22. Glaciers Glacier -large mass of ice that moves slowly over land
-two types: valley (alpine) and continental

23. Valley/Alpine Glacier
Continental Glacier
-long, narrow
-forms when snow/ice build up high in mountain valley
-usually move down valleys cut by rivers
-covers much of a continent or large island
-much larger than valley
-covers 10% of Earth’s land
- Antarctica & Greenland

25. Ice Ages
-continental glaciers covered large parts of Earth’s surface
-last ice age lasted 70,000 years and ended 10,000 years ago

26. How glaciers form & move
-only form in area where more snow falls than melts
-snow builds year after year
-pressure on bottom layers turns snow into ice
-valley g. flow a few cm to m each day
-continental flow in all directions

28. Glacial Erosion
Plucking
-two processes: plucking and abrasion
-as glacier flows, it picks up rocks
-weight of ice breaks rock
-carries rocks as it moves

29. Abrasion
Deposition
-gouges, scratches bedrock as glacier drags rocks
-glacier melts, deposits sediment eroded from land
-creates landforms

30. Till
Moraine
-deposits directly on surface
-many different sized particles
-ridge formed when till is deposited at edge of glacier
-ex. Long Island in New York

32. Kettle
-small depression that forms when ice is left in till
-ice melts, kettle remains
-often fills with water forming ponds/lakes
-ex. the Great Lakes

34. Waves How waves form -waves get energy from blowing wind
-energy causes water particles to move up and down
-water particles don’t move forward
-only form of the wave moves
-as waves approach shore, it drags on the bottom
-friction causes waves to slow

35. -major erosion force along coasts -erode land by impact
Erosion by Waves
-major erosion force along coasts
-erode land by impact
-large waves hit with great force
-breaks apart rock
-also erode by abrasion
-sediment picked up by wave
-wears rock like sandpaper
-energy of wave depends on headland
-part of shore that sticks out
-harder rock; resists waves

36. Landforms
-waves hit same area over and over
-erodes base of land along steep coasts
-places of soft rock form sea caves
-also forms sea arches; pillar of rock above water

38. Deposits
-waves shape coast thru erosion & deposition
-as waves slow, they drop sediment
-similar to river deposition
-forms beaches

39. Beach
-area of wave-washed sediment along coast
-usually sand
-comes from rivers that flow into ocean
-some are coral/shells piled up

40. Longshore Drift
Spit
-movement of sediment caused by waves hitting shore at angles
-forms a spit
-beach that projects like a finger into water

42. Wind How Wind Causes Erosion -weakest agent of erosion
-effective in deserts

43. Deflation
-process by which wind removes surface materials
-main way wind causes erosion
-stronger the wind, larger the particles that can be picked up
-doesn’t usually greatly effect land
-creates areas of rock fragment called desert pavement
-produces bowl-shaped hollows called blowouts
-abrasion polishes rock

45. Deposits from wind erosion
Sand Dunes
Loess
-forms: sand dunes & loess deposits
-deposit of windblown sand
-different shapes & sizes
-can move over time
-fine, wind-deposited sediment
-helps to form fertile soil

47. Gravity
Mass Movement
Force that moves rock downhill.
-caused by gravity
-different types: *Landslides
*Mudslides
*Slump
*Creep

48. Landslides
Mudflow
-rock/soil slide quickly down a slope
-rapid downhill movement of water, rock/soil
-occurs after heavy rains in a dry area

50. Slump
Creep
-mass of rock/soil slips down a slope
-occurs when water soaks the base of a mass rich in clay
-slow downhill movement of rock/soil
-often results from freezing/thawing