Flashcards in Section 1 - Rivers (Weathering) Deck (8)
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1
Q
Name the 3 types of weathering
A
- mechanical
- chemical
- biological
2
Q
What is mechanical weathering?
A
The breakdown of rock without changing its chemical compostion
3
Q
Name a type of mechanical weathering and its process
A
Freeze-thaw weathering
- When temp of water alternates above and below 0 degrees
- Water gets into the cracks in rocks (granite)
- When the water freezes it expands, putting pressure on the rock
- When the water thaws it contracts, releasing the pressure on the rock
- Repeated freezing and thawing widens the crack and causes the rock to break up
4
Q
What is chemical weathering?
A
The breakdown of rocks by changing their chemical composition
5
Q
Name a type of chemical weathering and its process
A
Carbonation weathering
- Rainwater has CO2 dissolved in it, which makes it a weak carbonic acid
- Carbonic acids react with rocks that contain calcium carbonate (limestone) so the rocks are dissolved by the rain water
6
Q
What is biological weathering?
A
The breakdown of rocks by living things
7
Q
Name a type of biological weathering and its process
A
Plant roots break down rocks by growing into the cracks on the rocks surface and push them apart
8
Q
What is weathering in drainage basins?
A
The breakdown of rocks WHERE THEY ARE (the material doesn’t get transported like in erosion)