Section 1 - Rivers (Weathering) Flashcards Preview

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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

  1. When temp of water alternates above and below 0 degrees
  2. Water gets into the cracks in rocks (granite)
  3. When the water freezes it expands, putting pressure on the rock
  4. When the water thaws it contracts, releasing the pressure on the rock
  5. 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

  1. Rainwater has CO2 dissolved in it, which makes it a weak carbonic acid
  2. 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)