Weathering And The River Valley Flashcards
What are the three main types of weathering?
Mechanical weathering, chemical weathering and biological weathering
How are rocks broken down in a drainage basin?
By weathering
Name a type of mechanical weathering?
Freeze-thaw weathering
What is mechanical weathering?
The breakdown of rock without changing its chemical composition
In which 5 ways does mechanical weathering occur?
When the temperature alternates above and below 0 degrees celsius.
When water gets into rock that has cracks.
When the water freezes and expands.
When the water thaws and contracts.
Repeated freezing and thawing.
Name a type of chemical weathering?
Carbonation weathering
What is chemical weathering?
The breakdown of rock by changing its chemical composition
How does chemical weathering occur?
When the rainwater has carbon dioxide dissolved in it, which makes it a weak carbonic acid.
When the carbonic acid reacts with rock that contains calcium carbonate.
What is biological weathering?
The breakdown of rocks by living things
What is a river course?
The path of a river as it flows downhill
What changes along the river depending on whether erosion or deposition is having the most impact?
The shape of the valley and channel
What does the long profile of a river show you?
How the gradient changes over the different courses
What does the cross profile of a river show you?
What a cross-section of a river looks like
