1. Deposition, Weathering, and Erosion
JH - KEADLE
Deposition, Weathering, and Erosion

2. Weathering

3. What Caused This?

4. vocabulary
word!
weathering - is a process that breaks down rock and other substances at Earth’s surface
very slow process
creates soil
softer rock weathers faster
weathering is fastest in hot and wet climates

5. Types of Weathering
mechanical weathering
chemical weathering

6. What is Mechanical Weathering?
vocabulary
word!
mechanical weathering - breakdown of rock into smaller pieces without any change in the chemical composition of its minerals.
Sometimes called “physical” weathering
Rock is torn apart by physical force, rather than by chemical breakdown.

7. Mechanical Weathering
ice wedging exfoliation thermal expansion biotic

8. Mechanical - Ice Wedging
vocabulary
word!
ice wedging - occurs when water fills cracks in rock then freezes and thaws over a long period of time.
The expanding ice cause the rock to eventually break.

9. Mechanical - Exfoliation
vocabulary
word!
exfoliation - rock breaks off into leaves or sheets along joints which are parallel to the ground surface.

10. Mechanical - Thermal
vocabulary
word!
thermal weathering - rock split by daily heating and cooling as different minerals in the rock expand and contract.

11. Mechanical - Biotic
vocabulary
word!
biotic weathering - weathering caused by living organisms
plant roots, digging animals, microscopic plants and animals, algae and fungi.

12. Mechanical Weathering

13. Demo 1 Mechanical Weathering

14. What is Chemical Weathering?
vocabulary
word!
chemical weathering - breakdown of rock into smaller pieces because of change in the chemical composition of its minerals.
Chemical reactions break down the bonds holding the rocks together, causing them to fall apart.
Chemical weathering occurs in all types of rock but smaller rocks are more susceptible because they have a greater amount of surface area.

15. Chemical Weathering Types of chemical weathering oxidation (oxygen)
hydrolysis (water)
carbonation (carbon dioxide)
biotic (living organisms)
acid rain

16. Chemical - Oxidation
vocabulary
word!
oxidation - oxygen combines with elements in rocks to form new types of rock. Often, there is a rusting effect on the rock.

17. Chemical - Hydrolysis
vocabulary
word!
hydrolysis - water combines with the substances in rocks to form new types of rock.

18. Chemical - Carbonation
vocabulary
word!
carbonation – carbon dioxide is dissolved in water making carbonic acid, which eats away at the rock.
Weak acid is formed when carbon dioxide in the air mixes with rain. This is the same acid found in soft drinks. 

19. Chemical - Biotic
vocabulary
word!
biotic - living organisms can cause changes in the chemistry of rock.
Plants lower the local pH to make it more acidic
Bacteria act as catalysts in various geochemical processes

20. Chemical Weathering

21. Demo 2 Chemical Weathering

22. Weathering by Water
Water is the strongest agent of chemical weathering
It can dissolve rock and minerals in rock

23. Weathering by Waves Waves weather the land: Mechanical weathering
Broken down into smaller pieces
Chemical weathering
Dissolved in water

24. Weathering by Waves

25. Weathering by Wind Wind weathers the land by mechanical means
abrasion
Very slow process

26. Weathering by Wind

28. mechanical weathering
The breaking down of rock into smaller pieces that remain next to each other. Weathering forms sediments
mechanical weathering
chemical weathering
Physical breaking of rock without any change in the chemical composition of the rock.
The breaking down of rock into smaller pieces because of chemical changes within the rock.
ice wedging
biotic force
biotic
oxidation
exfoliation
thermal
hydrolysis
carbonation

29. Erosion

30. What Caused This?

31. Erosion
erosion - movement of weathered rock and soil to a new location.
gravity
water
glaciers
waves
wind

32. What Is Gravitational Erosion?
downward movement of rock and sediments, mainly due to the force of gravity.

33. Erosion by Gravity Gravity can erode landscapes Landslides Mudflow
Slump
Creep

34. Erosion by Water
Moving water is the strongest agent of erosion that has shaped Earth’s land surface.
Erosion by water starts with rain. As the rain runs downhill, it carries soil rock and other material with it.

35. Erosion by Water
The rate depends on amount of rain, vegetation, type of soil, shape of land, and how people use the land
As water moves fast, it picks up sediment
As water slows down, it drops sediment

36. Water

37. What Is Glacial Erosion?
moves and carries rocks, grinding the rocks beneath the glacier
Glaciers pluck and abrade to cause erosion.

38. Erosion by Glaciers

39. What Is Wave Erosion?
Waves - relentless pounding of waves that erodes the weaker, softer rock
Can take over 100 years to erode a rock to sand

40. Erosion by Waves
When waves hit rocky coastlines, the impact can break off pieces of the rock
The sand and sediment in the waves can also act like sandpaper and wear away rock

41. Waves

42. Station 3 Wave Erosion

43. What Is Wind Erosion?
wind picks up surface material and moves it, weakest agent of erosion
responsible for creating great deserts like the Sahara Desert and Gobi

44. Wind

45. Station 4 Wind Erosion

46. erosion
Movement of sediments from one place to another.
wind
glaciers
water
gravity
waves

47. Deposition

48. Deposition
vocabulary
word!
deposition - laying down (dropping) of sediment carried by wind, water, or ice

49. Deposition by Water Water is the strongest agent of deposition.
Rivers deposit soil and sediment on their flood plains and deltas
Good farmland is usually based on land where sediment was deposited by water

50. Deposition by Water
Water Deposition

51. Deposition by Glaciers
When a glacier melts, it deposits the sediment it eroded from the land
This deposition can create new landforms and deposit sediment in new areas
till – material deposited on the land’s surface
moraine – ridge at the edge of a glacier

52. Glacier Deposition

53. Deposition by Waves
Waves shape coastlines by depositing sand on the beach.
The type of sand is determined by the sediment on the ocean floor
white sand
black sand
pink sand
green sand

54. Deposition by Waves

55. Deposition by Wind Wind is the weakest agent of deposition.
When it drops the sediment it is carrying, it can form dunes or mounds .

56. Deposition by Wind

57. deposition
Laying down of sediment that was carried in from another place.
wind
water
waves
glacier

58. Wind, water, and waves work together in the processes of deposition, weathering, and erosion.

59. What’s the Difference? WEATHERING - think weather wearing rock down
EROSION - think of a road and traveling
DEPOSITION – think of depositing money in a bank