1. 1. What are the two main types of weathering?
Warmup
1. What are the two main types of weathering?

2. Weathering and Erosion
Weathering breaks down the rocks, erosion moves the particles, and deposition drops the sediments in another location.
Badlands National Park, South Dakota

3. Arches National Park, Utah
Weathering
The process in which water, ice, and heat break down rock into smaller pieces, called sediments.
Arches National Park, Utah

4. Mechanical (physical) Weathering
Physical Weathering – the breakdown of rocks and minerals into smaller pieces without a change in chemical composition.
Frost Wedging
Root/Plant Wedging
Abrasion

5. Mechanical (physical) Weathering
Frost Wedging - alternate freezing & thawing of water that causes rock to break or crack
Root/plant wedging – plant roots growing into existing joints and fractures.

6. Abrasion- when rocks rub against each other

7. Badlands National Park, South Dakota
Chemical Weathering
The breakdown of rocks and minerals into smaller pieces by chemical action.
Badlands National Park, South Dakota
7 Colors Hill, Argentina

8. Badlands National Park, South Dakota
Chemical Weathering
Oxidation- when oxygen unites chemically with a mineral. Ex. Rust (iron oxide)
Badlands National Park, South Dakota
7 Colors Hill, Argentina

9. Hydration- when water unites chemically with minerals.

10. Mechanical (physical) Weathering
Chemical weathering
Pressure/stress release
Organic acid (moss, lichen, or pine needles)
Abrasion by wind, water, or human activity
Hydrolysis (reacting with water)
Gravity (mass wasting)
Acid precipitation
Exfoliation
Hydration (dissolving in water)
Ice wedging
Oxidation (metal and oxygen)
Biological (animal burrows, roots)

11. Rates of Weathering
Surface area - If particle size goes down then weathering rate goes up (more surface area exposed).
Weathering eats away sharp edges first (makes things round)

12. You saw this last week when talking about clasts (the grains in a sedimentary rock)

13. Rates of Weathering
Climate- the average weather of a location over time (precipitation and temperature)

14. Rock type and composition
Rates of Weathering
Rock type and composition
Different minerals weather at different rates.
Hard rocks weather slowly
Soft rocks weather quickly

15. Erosion and Deposition
Erosion – the process where sediments are transported by:
Wind
Gravity
Glaciers
Running water
Living Things
Deposition –The process in which sediment is dropped and comes to rest

16. Erosion
Wind Erosion– hot and dry areas especially (little ground cover to stop erosion).
Glacial Erosion– scrape and gouge, carry debris

17. Erosion
Rill erosion – caused when water runoff is heavy (after rainfall)
Gully Erosion – removal of large amounts of soil by heavy rainfall

18. Earth Science Work on poster Work on rock cycle study guide
Work on cheat sheet for Friday’s QUIZ!