1. Weathering Erosion and Deposition

2. Weathering
The breakdown of rock into smaller pieces (Sediment)

3. Mechanical Weathering
Rocks broken into sediment by physical means
Types
Frost heaving and Frost wedging
Plant roots
Friction and impact
Burrowing of animals
Temperature changes

4. Frost Wedging
Expansion of cracks in rock due to freezing ice

6. Frost Heaving
Wet soil freezes, pushing up the ground above

7. Plant Roots

8. Friction and Repeated Impact

10. Burrowing of Animals

11. Temperature Changes

12. Chemical Weathering
The process that breaks down rock through chemical changes.
The agents of chemical weathering
Water
Oxygen
Carbon dioxide
Living organisms
Acid rain

13. Water
Water weathers rock by dissolving it

14. Oxygen
Oxygen makes iron rust.
Rust is unstable

16. Carbon Dioxide
CO2 in soil dissolves in rain water and creates carbonic acid
Easily weathers limestone and marble

17. Living Organisms
Lichens produce weak acids

18. Acid Rain Compounds from burning fuels (NOx SO4) form acids in rain.
Very rapid chemical weathering

19. Karst Topography
A type of landscape in rainy regions where there is limestone near the surface, characterized by caves, sinkholes, and disappearing streams.
Created by chemical weathering of limestone

20. Features of Karst: Sinkholes

21. Features of Karst: Caves

22. Features of Karst: Disappearing Streams

23. Soil Soil is the product of weathering rocks and dying living things.
Mixture of sediment and organic matter
Plants, as well as Fungi, Bacteria, and Invertebrates mix soil over time to form different layers.
OM broken down by FBI is called Humus

24. Soil Profile
A cross section of soil that shows the different layers, called horizons.
There are 4 different horizons

25. O horizon Top layer 100% organic matter (living or dead)
No sediment, therefore not soil.

26. A Horizon The top layer of soil, often referred to as topsoil.
Dark in color because it has lots of organic matter.
Also contains roots and animals.

27. B Horizon Middle layer of soil
Lighter because it has less organic matter
Some plant roots
Leeching – water bringing nutrients from one layer into the next

28. C Horizon Deepest layer of soil
Contains no Organic matter, only weathered rock.
Little to no nutrients.

29. Soil Profiles (cont) Soil profiles differ in different areas
Thickness of the various layers depends on the climate type as well as the plant/animal activity above.

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

32. Erosion Factors Rate of Rain Slope of land Plants
More rain  More Erosion
Slope of land
Steeper land  More Erosion
Plants
Fewer Plants  More Erosion

33. Humans Increase erosion Decrease Erosion Plowing Overgrazing animals
Clear cutting forests
Decrease Erosion
No-Till farming
Contour Farming
Terracing
Selective cutting of forests

41. Water Erosion
Rivers, streams, and runoff

42. Rills and Gullies
Rill and Gully Erosion occur when water moves over steep areas, carving out channels.
Rills are formed by small streams.
Gullies are formed as rills become broader and deeper due to more water.
The fast moving water removes sediment.

45. Sheet Erosion
Sheet erosion occurs in flat areas where the water slows down.
Water flows in wide sheets rather than streams
Because the water has less energy, it deposits much of its sediment

47. Ice Erosion
Glaciers

48. Glaciers Valley Glaciers - small glaciers between mountains
Leave U-shaped valley.
Continental Glaciers - large glaciers that cover vast areas.
Currently cover 10% of earth

50. Glacial Erosion Glaciers erode as they move.
They can pick up sediment and move it great distances - Plucking
They can also scrape the surface rock resulting in striations

53. Glacial Deposition Glaciers drop their sediment (till)as they melt.
Moraines - pile of sediment perpendicular to movement
Eskers – winding pile of sediment parallel to movement
Drumlin – Streamlined piles of sediment parallel to movement
Glacial Erratic - single large rock dropped by glacier

58. Wind Erosion

59. Wind Erosion Deflation – Wind picks up sediment
Abrasion – Wind carried sediment acts as a sand blaster
Loess – fine sediment deposited by slowing wind
Dunes – piles of sand constantly moved by wind

62. Gravity Erosion (Mass Movements)
Slumps, Creeps, Rockslides and Mudslides

63. Slumps
Occurs on a steep slope when loose materials slide down the slope in one large mass.
Layers under the soil are weakened due to erosion or earthquakes.
Leaves curved scar in soil

64. Creep Slow mass movement down a less steep slope.
Often caused by repeated thaw melt cycles.
Causes tree and fence-posts to lean downhill.

68. Landslides & Rockslides
Large areas of rock/soil break loose from a steep slope and move quickly downhill.
Occur often after earthquakes or heavy rains.
Fan-shaped piles of sediment at the bottom of a slope is good evidence of slides

70. Mudflow Occur as mixtures of water and sediment flow down a slope.
Occur after heavy rains in areas of thick dry sediment.
Water and sediment forms a thick paste that has lots of momentum, and causes lots of damage.