Coasts Flashcards
What is freeze thaw weathering?
rainfall gets trapped in cracks where it freezes and expands. when the process happens repeatedly, the rock will weaken and eventually shatter
What is a slump?
a rotational movement
What is a slide?
a movement along an existing surface
What is rockfall?
fragments break away due to weathering
What is rotational slip?
slump of saturated soil along a curved bedding plane
What is Mudflow?
Saturated soil flows down a steep slope
What is a landslide?
Where rocks slides downhill when layers are loosended
What is the difference between a rock slip and a rock slide?
- A rock slip is when random pieces of rock fall from a cliff
- A rock slide is where rock moves over a plain of another type of rock
Explain how constructive waves shape the coastline
- strong swash and weak backwash means that material is deposited and beaches form.
- long shore drift moves material into river mouths resulting in spits
Explain how destructive waves shape the coastline
- strong backwash and weak swash means that material is eroded and taken away
- usually forms features such as arches, headland and wave cut platforms
Describe the process of abrasion
The coast is worn down by material carried by the waves which is thrown at the rock at high velocity
Describe the process of Solution
Chemical action of sea water which slowly dissovles the rocks on the coast.
Describe the process of Solution (erosion)
Chemical action of sea water which slowly dissovles the rocks on the coast.
Describe the process of Hydraulic action
The force of the water. Waves enter cracks in the coastline and compress air within the crack, when the wave retreats the air expands quickly causing the rock to break
What is a constructive wave?
- strong swash, weak backwash
- high wave in proportion to its length
What is a destructive wave?
- weak swash, strong backwash
- high wave in proportion to its length
What is a destructive wave?
- weak swash, strong backwash
- high wave in proportion to its length
- formed with large winds and a long fetch
What is long shore drift?
the transport of sediment along a stretch of coastline caused by waves approaching the beach at an angle
What are the causes of sea level rise?
- Thermal expansion (temperature of water rises as it expands)
- melting land ice (melt water flows into the sea and adds to its level
What are the impacts of sea level rise?
- polluted water
- less food
- less habitats
- colder seas
What is hard engineering?
Hard engineering options tend to be expensive, short-term options. They may also have a high impact on the landscape or environment and be unsustainable.
What is soft engineering?
Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable, with less impact on the environment.
What is RipRap/rock armour (hard)?
- large boulders piled up to form a type of sea wall
- gaps allow some water through and disperses the energy of the waves reducing the erosion power.
What is Gabions (hard)?
- Large steel mesh cages filled with rocks
- absorbs the seas energy so it causes less damage
How is a tombolo formed?
When a spit continues to grow outwards joining to an offshore island. This requires the island to be located at the mouth of a river.
How is a Bar formed?
A bays is formed so longshore drift moves material between the two headlands in the direction of the prevailing wind. This forms a spit and eventually the spit will reach the second headland. A lagoon can form behind the bar.
How is a spit formed?
Longshore drift carries sediments along the coast. The swash moves material up the coast in the direction of the prevailing wind. If the coast changes direction, sediment continues to be dropped in the same direction. Meaning a long thin ridge of material is deposited- this is the spit. A change in wind direction can cause a hooked end.
When is deposition likely to occur?
When: waves enter shallow water, waves enter a sheltered area, there is little wind, there’s a good supply of material
How is a cove formed?
When rocks run in horizontal bands. The sea erodes the layer of harder rock using solution and hydraulic action. When it reaches the softer rock it is eroded quicker and this leaves a circular cove with a narrow entrance
How are Stacks. stumps, arches, and caves formed?
A line of weakness is eroded and it widens and deepens into a cave. Erosion continues through the processes of corasion and hydraulic action until it extends all the way through to form and arch. The roof of the arch is weathered and the weight eventually becomes too much causing it to collapse forming a stack. Erosion continues until a stump is left.
How is a wave cut platform formed?
Cliff face is eroded by solution, hydraulic action and abrasion weakening the cliff. This cliff breaks away leaving a wave cut notch, erosion continues and the cliff is undercut until it eventually falls leaving a wave cut platform.
What is a salt marsh?
A coastal ecosystem between land and the sea
