1. Weathering and Erosion Unit 4 Study Guide
Unit Test on ______________.

2. THE BIG IDEA OF THIS UNIT:
- Changing Earth’s Surface
THE BIG IDEA OF THIS UNIT:
Weathering, erosion, and deposition act together in a cycle that wears down and builds up the Earth’s surface.

3. Weathering
the process by which rock is broken down very slowly (much slower than earthquake activity, landslides, or volcanic activity)
Just breaking down-
not moving yet!

4. Mechanical Weathering
breakdown of rock into smaller pieces by physical means
The rock is still a rock, just smaller.

5. Ice Wedging
alternate freezing and thawing of water that seeps into the cracks of rocks and cause breakage
Ex. potholes

6. Ice Wedging

7. Yosemite National Park, California

8. Abrasion
the grinding and wearing away of rock by wind, water, or gravity

10. Exfoliation
the peeling or flaking of rock due to repeating heating and cooling

11. Exfoliation

12. Plants
the roots of plants grow down into the rock and eventually bust it apart (root pry is an example)

13. Root Pry

14. Animals
can wear down rock as well

15. Animals
Animal burrowing
causes weathering to
occur.

16. Chemical Weathering
rock breaks down as a result of a chemical reaction
It doesn’t just look different, it IS different!

17. Acid Precipitation
rain, sleet, or snow that contains a high concentration of acids (sulfur, nitrogen, and carbon oxides); acid rain can dissolve the limestone that is on some buildings.

18. Acid Precipitation

20. Plant acids (Humic acids)
moss and lichens, which are fungi and algae living together, can break down rock

21. Oxidation
oxygen in the air can cause rust

22. Weathering creates sediments.

23. Then, sediments get carried away.
Erosion- the process in which weathered rock and soil (sediments) are transported/ moved from one place to another; Example – The Rocky Mountains have sharp peaks and are younger than the Appalachian Mountains because they haven’t been eroded as much.

24. Erosion

25. 4 Agents (causes) of Erosion:
Gravity
Water
Wind
Waves

26. 1) Gravity/Mass Movement
when gravity pulls rocks and soil downhill
Landslide – sudden mass erosion of rocks, trees, and soil downhill

28. Landslide Video

29. Gravity/Mass movement
b. Mudslide- sudden mass erosion of mud downhill Click on the video link.

30. Gravity/Mass Movement
c. Creep – slow movement of soil, rocks, and plants down a slope where plant roots and tree trunks begin to lean toward the soil as erosion continues

31. Creep

32. - The Force of Moving Water
happens when water picks up materials and carries them away; running water changes the Earth’s surface more than any other agent

33. Runoff – water flowing across the Earth’s surface; most sediment washes or falls into a river

34. b. Rivers – V-shaped valleys and canyons can be caused by erosion from running water

35. c. Glaciers – frozen “rivers of ice” that can make U- shaped valleys

36. How Glacier Erosion Shapes the Land
- Glaciers
How Glacier Erosion Shapes the Land

37. V-shaped by water, followed by U-shaped by ice

38. U-shaped Valley

39. 3) Wind
occurs when wind picks up loose sediments and carries them in the air

40. - Wind
Wind Erosion

41. SANDSTORM LEAVING NORTH AFRICA TOWARDS THE ATLANTIC – CANARY ISLAND.

42. Wind Erosion- The Dust Bowl
Wind erosion is one cause of soil loss. For example, wind erosion contributed to the Dust Bowl on the Great Plains. The Dust Bowl ruined farmland in western Oklahoma and parts of the surrounding states. Wind blew dry particles of soil into great clouds of dust that traveled thousands of kilometers.
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