Coasts and glaciation Flashcards
What is a spit?
A spit is an area of land that comes out of a coastline.
Name some methods of protecting the coasts and list their prices.
- Building sea walls (£7m per km)
- Rebuilding the beaches (£2m per km)
- Groynes (£1.5m per groyne)
- rip-rap (£3m per km)
Explain the following method and costs of protecting the coasts:
Groynes
- Low walls built down the beach and into the sea
- About 200m apart
- Slow movement of material along the coast and help build up the beach
- Beach helps protect the land.
Cost: £1.5m per groyne
Explain the following method and costs of protecting the coasts:
rip-rap
- Mixture of large boulders and concrete blocks
- Protects the coast by breaking up waves
- Don’t protect as well as a sea wall but help retain the beach
- Can look ugly and make access to the beach difficult
Cost: £3m per km
Explain the following method and costs of protecting the coasts:
rebuilding the beaches
- Replaces sand and shingle that has been lost from the beach
- Beach absorbs the energy from the waves
- Protects land or sea wall behind the beach and looks more natural
Cost: £2m per km
Explain the following method and costs of protecting the coasts:
building sea walls
- Concrete wall
- Stops waves reaching the land
- Also reflect the waves back to the sea
- Give good protection but are expensive and may need repaired.
Cost: £7m per km
What is a bay?
A opening in the coastline created where soft rock was found
What is a headland?
A stretch of land jutting out into the sea. Formed where hard rock is found.
How is a headland eroded by the sea?
The sea picks up rocks in stormy conditions and throws them at the the shore.
This attacks cracks and opens them.
The cracks get larger and develop into a small cave.
The cave is eroded further over time until it wears right through creating an arch.
Further errosion cuase the arch to collapse leaving a pillar of rock away from the coast called a stack.
Look at diagram of crack, cave, arch and stack.
What is longshore drift do?
This is where waves cause material to be moved along the shore.
It happens when waves approach the beach at an angle.
Explain the process of longshore drift.
- Waves approach the shore at an angle.
- The swash (wave coming in) causes material to ge wahsed up onto the shore.
- The backwash (wave going out) pulls material directly back into the sea (not at an angle)
- Process repeats slowly moving material along the shore.
How was Spurn Head spit formed (study diagram)
EROSION:TRANSPORTATION:DIRECTION-DEPOSIT:GROWS OUT:CURVE:MARSH
- The coastline north of Spurn Head is eroded (EROSION)
- The eroded material is transported by sea currents down the coast. (TRANSPORTATION)
- Where the coastline changes direction this material is deposited. (DIRECTION-DEPOSIT)
- The spit grows out from the coast as more material builds up (GROWS OUT)
- Action of the waves causes the end of the spit to be curved. (CURVE)
- Behind the spit marshland is formed. (MARSH)
Clockwise from 9 o’clock.
How does cliff collapse happen?
Weather
- Rain soaks into cracks dissolve minerals and weakening the structure
- In winter water in the cracks freezes and expands opening up the cracks
- Rain makes clay very heavy and slippery meaning huge sections slip down.
Sea
* Waves crash into the cliff wearing away the rock
* Pebbles/rocks thrown by the waves undercut the cliffs
* Cliff collapses and erored material is carried away by the sea leaving no protection.
What is an Arête
Narrow knife-edged ridge formed during glaciation when two corries erode towards eachother
