1. Weathering and Erosion

2. Weathering
The breakdown of the materials of Earth’s crust into smaller pieces.

3. Mechanical Weathering
Process by which rocks are broken down into smaller pieces by physical means.
Types of Physical weathering
Ice wedging
Organic activity- plants and animals (Plant roots, Animal activity burrowing, moving soil)
Abrasion
Exfoliation

4. Ice Wedging

5. Plant Roots (organic activity)

6. Animal Activity (Organic activity)

7. Abrasion The scraping of materials together

8. Exfoliation
As pressure reduces on exposed rock, the granite expands, resulting in long curved cracks and layers that peel away from the rock. NOT SEEN IN ALABAMA

9. Chemical Weathering
The process that breaks down rock through chemical changes.
The types of chemical weathering
Carbonation
Hydrolysis
Oxidation

10. Hydrolysis
The interaction of water with other substances to weather rock- important in soil formation

11. Oxidation
Iron combines with oxygen in the presence of water in a processes called oxidation
The product of oxidation is rust

12. Carbonation CO2 dissolves in rain water and creates carbonic acid
Carbonic acid easily weathers limestone and marble

13. Carbonation, Continued
Chemical weathering of limestone, breakdown of calcite
Results in Karst Topography - A type of landscape characterized by caves and sinkholes.

14. Features of Karst: Sinkholes

15. Features of Karst: Caves

16. Features of Karst: Disappearing Streams

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

18. Water Erosion
Rivers, streams, and runoff

20. Ice Erosion
Glaciers

22. Wind Erosion

23. Mass Movements (Gravity)
Landslides, mudslides,

24. slump and creep

25. Talus
Rocks at the base of a slope deposited by gravity

26. Rates of Weathering
How quickly or slowly a rock weathers and erodes depends on several factors:
Rock Composition
Exposure
Climate
Topography
Human Activity

27. Rock Composition
Some rocks are more resistant to weathering. For example, rocks comprised of quartz are more resistant to weathering since quartz is so stable, having crystallized last from
the magma chamber.

28. Climate

29. Human Activity
Mining, Construction, Transportation, Recreational activities all contribute to wearing away and eroding rocks

30. Topography
The elevation and slope of the land surface affects its rate of weathering, for example:
Colder temperatures at higher elevations, more ice wedging
Low elevations – more erosion by wave action
Steep slopes more affected by gravity

31. Exposure
The more rock exposed, the more weathering can occur, so the rate of weathering increases.