1. Chapter 12
Weathering
The breakup of rock due to exposure to processes on the Earth’s surface

2. Mechanical Weathering
There are 4 types of physical weathering…..
Breaking a rock into smaller pieces WITHOUT changing it’s composition
DISINTEGRATION or “physical” weathering

3. Frost Wedging
Water in the cracks of rock freezes, expands and pushes the rock apart, breaking it
Remember, water EXPANDS as it freezes

5. Abrasion
TO SCRATCH
Water, wind or glaciers can move sand, gravel and other rocks causing them to scrape against one another, wearing each other away

6. Plant and animal action
Tree roots can grow into rocks, breaking them apart
Animals can dig into the soil, breaking rocks and allowing water to weather it

7. Exfoliation
Rocks that get pushed upward become exposed to the air, breaking or peeling off

8. Chemical Weathering
There are 3 types of chemical weathering…..
A rock’s minerals are changed into different substances; hence the composition changes
DECOMPOSITION

9. Reaction with water
Water can dissolve minerals
Water can combine with gases to make acids, eating away at rock
Carbonic Acid
Hydrolysis

10. Acid Rain
Water combines with air pollutants like Nitrogen and Sulfur to create acids

11. Oxidation
Chemical reaction of oxygen with other substances, thus causing rust

12. Rates of Weathering…..
Mechanical Weathering….
Chemical weathering….
Prefers a cold, dry climate
Prefers a warm, moist climate

13. Mineral composition…
Some minerals are more resistant to weathering, like quartz
Sandstone weathers easily while marble does not