Weathering And Mass Movement Flashcards
What is weathering?
Wen rocks are broken down or softened in situ (in a resting place)
What does to leave the land fallow mean?
The keep it resting.
What is erosion?
When weathered material is carried away by wind, water, gravity, etc.
What are the three main types of weathering?
Physical, chemical and biological.
How does physical weathering work?
It is the disintegration of rock into smaller pieces by physical processes without any change in the chemical composition of the rock. Two examples are freeze-thaw and exfoliation.
How does chemical weathering work?
It is the decomposition of rocks caused by a chemical change within the rock. An example is limestone solution.
How does biological weathering work?
When tree roots penetrate and widen bedding planes and other weaknesses in the rock until blocks of rock become detached.
What is freeze-thaw?
Occurs in cold climates when cracks in the rocks fill up with water during the warmer days and it then freezes at night when it gets colder again. The ice then expands, causing the cracks to deepen and eventually pieces of the rock break off if it is repeated over time.
What is exfoliation, or onion weathering?
Occurs in warmer climates when the rock is repeatedly heated and cooled, stressing the outer layers which eventually start peeling off like an onion does.
What is limestone solution/carbonation?
Occurs when rainwater chemically reacts with rock such as limestone, which contains calcium carbonate, and dissolves the rock slowly. It is then eroded away by running water.
Where does freeze thawing occur?
In a cold, mountainous area.
Where does exfoliation occur?
In a hot, rocky desert.
Where does limestone solution/carbonation occur?
In a limestone area.
Where does biological weathering occur?
In a woodland area on a rocky slope.
Where does physical weathering occur?
Most likely to occur in areas of bare rock where there is no vegetation to protect the rock from extremes of weather.
