Paper 2, Section A : Land/Water Based processes Flashcards
What is weathering?
The breakdown of rocks by natural processes
What is biological weathering?
When plants and animals wear away rocks
What is chemical weathering?
When weak acid from rain water wears away the Rock
The acid reacts with alkaline rock ( limestone and chalk ) and dissolves it
What is mechanical / physical weathering?
Freeze-thaw weathering:
Changes in temperature cause water in a crack of a rock to freeze and expand and melt and contract , overtime weakening the rock
What are the three weathering processes?
Biological
Chemical
Physical
What are the four mass movement processes?
Slides
Slumps
Falls
Soil creep
What are slides ?
A mass of earth or rock slides along a steep slope,
They are rapid
What are slumps?
Soft clay becomes saturated,
The weight of the cliff under gravity causes it to collapse,
They are rapid
What are falls?
Rockfall off the river or cliff face,
( Can be caused by physical weathering, the rocks fall due to gravity )
They are rapid
What are soil creeps?
Soil gradually moves forward, because the soil particles expand when wet and contract in dry periods
This is a slow movement
What are the two water based categories of processes?
Erosion
Transportation
What is erosion?
When the action of water wears down rock
What are the four processes of erosion?
Hydraulic action
Abrasion
Attrition
Solution
What is solution?
Weak acid in sea water or rain water in a river dissolves soluble rocks
What is abrasion?
When high energy waves or rivers scrape pebbles, sand and boulders along the river bed
What is attrition?
When rocks knock against each other
What is hydraulic action?
Water forces air into the crack of rocks, increasing pressure causes cracks to expand overtime
What is transportation?
The way that rivers or oceans carry their load
What are the four transportation processes?
Traction
Saltation
Suspension
Solution
What is traction?
Large, heavy boulders are rolled along the river bed
What is saltation?
Material is bounced along the river bed
What is suspension?
Light sediment is suspended in the water
What is solution (transportation)?
The transportation of dissolved chemicals/rocks
What is deposition?
When sediment is dropped by a river, wave or glacier
