Sub-Aerial Processes Flashcards
What are sub-aerial processes?
Land based processes which alter the shape of a coastline. They’re a combination of both WEATHERING and MASS MOVEMENT.
Physical WEATHERING processes
Freeze-thaw: involves water entering cracks in rocks and freezing. As water freezes, it expands, fracturing the rock.
Exfoliation: The repeated action of heating and cooling rocks causing them to “shed” of layers.
Biological WEATHERING processes
Seeds get into cracks in rocks and begin growing. They exert pressure on rocks as they grow, causing them to fracture.
Seaweed attaches to rocks so as the sea moves the seaweed , chunks of rocks are pulled away.
Chemical WEATHERING processes
Corrosion is technically a form of weathering, not erosion.
Hydrolysis -> involves the splitting of minerals due to their reactivity with water.
Oxidation -> rusting. Elements such as iron are susceptible to oxidation and can be found within minerals on coastlines.
What is MASS MOVEMENT?
The large scale movement of weathered material in response to gravity. E.g. A cliff has been weathered to the point it begins to collapse.
What is a rockfall?
Rocks are created as a result of freeze-thaw weathering on a cliff, which then free fall.
What is a landslide?
Cliffs are soaked with water and are therefore lubricated (particularly soft rock). They therefore begin to slip. These are similar to slumps.
What is soil creep?
An incredibly slow process occurring on gentle slopes, producing an undulated (wavy) surface. Damp soil moves slowly downhill due to increase in mass due to saturation of water.
What is rotational slumping?
Slumping happens when heavy rainfall saturates rocks and material, making the heavier. It happens on a concave surface, causing the cliff to form a crescent shape.
What is mudflow?
Very dangerous, occurring on steep slopes with saturated soil and little vegetation. Lack of vegetation promotes mass wasting as their is nothing soil can bind to. Saturated soil becomes heavy and lubricated, leading to rapid downhill movement of mud.
