Weathering Flashcards
1
Q
Physical Weathering
A
Physical forces such as wind, water and temperature changes
2
Q
Freeze Thaw Action
A
- cold, wet climate
- water fill cracks, freezes overnight and expands
- as water turns into ice, volume increases and puts pressure on sides = cracks
- very sharp, pointed scree fragments
3
Q
Exfoliation
A
- orange peel
- dry areas, big temperature changes
- rock expands in heat of day, contracts in cooler night, weakens outer layers
- large pieces peel off
4
Q
Weathering
A
Wearing away of the earth by action of weather
5
Q
Chemical Weathering
A
*rocks decompose when they come into contact with gasses in the air, changes chemical composition of rock, weakens rock
6
Q
Carbonation
A
- rain dissolves CO2 = carbonic acid
- comes into contact with rock, chemical reaction
- cold water absorbs more CO2 than warm water
- cold climates, stronger carbonic acid, rapid carbonation
- can dissolve calcium carbonate present in cement, will eventually collapse
7
Q
Hydrolysis
A
- water and silicates (granite and sandstone)
- certain silicate materials absorb water, clay
- clay is soluble and washed out of rocks easily
- unstable, begin to crumble
8
Q
Oxidation
A
- rusting
- metals that are left in rain
- O2 in water and iron in rocks = iron oxide
- weaker, easily broken down
9
Q
Biological Weathering
A
- plants, animals, people
* animals and plants increase likelihood of rocks being weathered by mechanical or chemical means
10
Q
Animals
A
Dig in soil, weaken soil and expose rocks to weathering
11
Q
Plant + tree roots
A
Penetrate into cracks, pressure, bigger cracks
12
Q
Lichens
A
- roots penetrate between grasses and rocks, eventually fall away
- produce an acid that breaks down minerals in a rock
