Erosion Flashcards
1
Q
What does the effectiveness of abrasion depend on?
A
- conc., hardness + energy of impacting particles + resistance of bedrock
2
Q
What is the relationship between velocity + abrasion?
A
- as velocity inc., abrasion inc.
3
Q
What does hydraulic action inc.?
A
- direct force of flowing water, + cavitation
4
Q
How does cavitation occur?
A
- bubbles implode + eject tiny jets of water w velocities up to 130m/s
5
Q
What is cavitation an important process in?
A
- rapids + waterfalls
6
Q
What are the key factors controlling rate of corrosion?
A
- bedrock
- solute conc. of stream water
- discharge
- velocity
7
Q
Where does max. rates of corrosion occur?
A
- fast-flowing, undersaturated streams passing over soluble rocks
8
Q
What are the factors affecting rates of erosion?
A
- load
- velocity
- gradient
- geology
- pH
- human impact (deforestation, dams + bridges)
9
Q
What are the 4 types of erosion?
A
- Abrasion (corrasion)
- attrition
- hydraulic action
- corrosion (solution)
10
Q
What is abrasion (corrasion)?
A
- wearing away of bed + banks by load carried by river
11
Q
What is attrition?
A
- wearing away of load carried by river (smaller, rounder particles)
12
Q
What is hydraulic action?
A
- sheer force of water causing rocks to fragment off the sides of rivers
13
Q
What is corrosion (solution)?
A
- water dissolving chemical ions (esp. Ca) that make up river channel
14
Q
What is cavitation?
A
- water forced in small cracks causes air to compress + explode under high pressure
