Coasts Flashcards
(23 cards)
Define erosion.
The wearing away of rock along the coastline
___________ waves cause erosion on the coastline.
Destructive
Name the 4 types of erosion on the coastline.
- Hydraulic action.
- Abrasion.
- Attrition.
- Solution.
What is hydraulic action?
The sheer power of the waves as they smash against the cliff.
What is abrasion?
When pebbles grind along a rock platform. Over time the rock becomes smooth.
What is attrition?
When rocks that the sea is carrying knock against each other. They break apart to become smaller and more rounded.
What is solution?
When sea water dissolves certain types of rocks, e.g. chalk, limestone.
Name the 3 types of weathering.
- Freeze-thaw.
- Biological.
- Chemical.
Name the 4 types of mass movement.
- Rockfall.
- Mudflow.
- Landslide.
- Rotational slip.
What is rotational slip?
Saturated soil slumps down a curved surface.
Name the 4 ways that beach material can be transported.
- Solution.
- Suspension.
- Saltation.
- Traction.
What is suspension?
Small particles such as silts and clays are suspended in the flow of the water.
What is saltation?
Small pieces of shingle or large sand grains are bounced along the sea bed.
What is traction?
Pebbles and larger material are rolled along the sea bed.
Deposition can occur on coastlines that have ____________ waves.
constructive
Name the 4 factors that lead to deposition.
- Waves starting to slow down and lose energy.
- Shallow water.
- Sheltered areas.
- Little or no wind.
Name the 3 groups of erosional landforms.
- Headlands and bays.
- Cliffs and wave-cut platforms.
- Caves, arches, stacks and stumps.
How do bays form?
Bands of soft rock are weaker so are eroded quickly.
How do headlands form?
When the softer rock is eroded inwards, the hard rock sticks out into the sea.
What is a wave-cut platform?
A wide gently-sloping surface found at the foot of a cliff.
How do wave-cut platforms form?
- The sea attacks the base of the cliff.
- A wave-cut notch/dent in the cliff is formed by erosional processes, such as abrasion and hydraulic action.
- As the notch increases in size, the cliff becomes unstable and collapses, leading to the retreat of the cliff face.
- The backwash carries away the eroded material, leaving a wave-cut platform.
- The process repeats and the cliff continues to retreat.
Caves, arches, stacks and stumps are usually found on a ________.
headland
Explain how a stump forms.
- A crack is widened in the headland through hydraulic action and abrasion.
- As the waves continue to grind away at the crack, it begins to open up to form a cave.
- The cave becomes larger and eventually breaks through the headland to form an arch.
- The base of the arch continually becomes wider through further erosion, until its roof becomes too heavy and collapses into the sea, leaving a stack.
- The stack is undercut at the base until it collapses to form a stump.
