Geography Coasts

How do waves form?

Waves are formed by blowing winds over the sea. The friction with the surface causes ripples in the water and these develop into waves.

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What are constructive waves?

Low waves that surge up the beach and have a powerful smash (lots of energy). Carry lots of sediment (rocks and pebbles)

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What are destructive waves?

Formed by local storms and can destroy the beach.Closley spaced, chaotic swirling mass of water.High and steep

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What is freeze thaw weathering?

Water ends up in cracks, water freezes and expands, making the cracks bigger. Fragments of rock will break off.

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What is salt weathering?

Seawater contains salt, when water evaporates it leaves salt crystals behind. Crystals grow and expand putting pressure on rocks resulting in break off.

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What is carbonation?

Rainwater absorbs CO2 from the airand becomes slightly acidic. Contact wit alkali rocks (limestone) cause a chemical reaction so break off slowly.

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What is mass movement?

Downward movement or sliding of material because of gravity.

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4 examples of mass movement...

Rockfall-fragments of rock break away from a cliff. Landslide-blocks of rock slide down a slope. Mudflow-saturated soil and weak rock flows down a slope. Rotational slip-slump of soil and weak rock along a curved surface.

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What is solution? (EROSION)

The dissolving of soluble chemicals in rocks (limestone).

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What is Corrasion? (EROSION)

When fragments of rock are picked up and hurled at a cliff by the sea. The rock scrapes and gouges the cliffs rock.

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What is Abrasion? (EROSION)

Sandpapering effect of pebbles grinding over a rocky platform making it become smooth.

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What is hydraulic power? (EROSION)

Power of the waves smashing against a cliff. Trapped air is forced into holes causing the rock to break apart. (Cavitation)

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What is longshore drift? (LSD)

Movement of sediment on a beach as a result of prevailing winds. (ZIG ZAG) Sediment is moved along the beach.

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Describe coastal deposition...

takes place in areas where the flow of water slows down. Waves lose energy so can't carry sediment, so it is dropped off.

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Describe headlands and bays...(EROSIONAL LANDFORM)

Bays are formed when weaker bands of rock (clay) are eroded. Tougher, harder rock is eroded more slowly so this rock sticks out to form headlands.

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What are cliffs and wave cut platforms? (EROSIONAL LANDFORM)

Cliffs are steep rock faces, especially at the edge of the sea. Erosion is high at the base of cliffs. Wave-cut platforms are the narrow flat area often found at the base of a sea cliff created by erosion.

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Describe Caves arches and stacks... (EROSIONAL LANDFORM)

Caves are formed when rock under a cliff is eroded ( void in the cliff). Over time and heavy erosion back to back caves may form a arch. Freeze thaw weathering on the roof causes the roof of the cliff to collapse, leaving an isolated section of rock.

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What are beaches and sand dunes? (DEPOSITIONAL LANDFORM)

Beaches are deposits of sand or shingle at the coast. Sandy beaches are found in sheltered bays. (strong swash). Sand dunes are areas at the back of the beach where large amounts of sand have been deposited.

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What are spits and bars? (DEPOSITIONAL LANDFORM)

A spit is a long, narrow stretch of sand or shingle jutting out into the sea. Formed as a result of longshore drift. Can change drastically over time. A bar is when a spit forms across a bay as a result of longshore drift.

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What are groynes? (Hard engineering)

Timber or rock structures built on the beach to trap sediment moved by LSD. Cost effective but look unnatural.

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What is a sea wall and rock armour? (Hard engineering)

A sea wall is a concrete barrier built at the sea to stop the power of the waves, can be very expensive and look obtrusive. Rock armour is a layer of boulders or large rocks at the foot of the cliff, used to break the waves up and absorb energy.

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What is beach nourishment and dune fencing? (Soft engineering)

Beach nourishment is the process of adding sand or shingle to a beach. (Looks attaractive and cheap.) Dune fences are constructed on a sandy beach to encourage dune formation and proetct original dunes.

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What is dune regeneration? (Soft engineering)

Sand dunes are effective buffers but are easily damaged. Process of adding more sand/shingle and marram grass to a dune.

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What is managed retreat?

A deliberate policy of allowing the sea to flood or erode an area. It is a good long term strategy.

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Geography Coasts

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Other cards in this set

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Card 4

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Card 5

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