Coastal Change And Conflict Flashcards
Describe the process of abrasion.
Waves pick up stones and hurl them against the cliff which wears away the rock.
Describe the process of attrition.
Pebbles carried by waves become rounder and smaller as the collide with each other.
How is a cave formed?
When the waves erode a weakness in the rock such as a joint or a fault.
How is an arch formed?
When two caves erode back from either side of the headland and meet in the middle.
How is a stack formed?
Formed when an arch collapses.
How is a stump formed?
When a stack is eroded by wind and water.
Explain how a wave cut platform is formed.
The rock gave over hangs the sea, a wave-cut notch is under utter by waves.
The cliff then retreats inland and the overhanging rock has collapsed and a wave cut platform is formed.
Destructive waves erode the coast because they have…
A weak awash and a strong backwash.
What are the properties of constructive waves?
They have a long wavelength, a strong swash and a weak backwash.
Describe longshore drift.
Waves approach the coast at an angle.
Swash pushes sand and gravel up the beach at the same angle.
Backwash carries sand and gravel back down the beach at 90 degrees under the force of gravity.
Sand and gravel move along the beach in a zig zag fashion.
Sand is lighter than gravel so moves further up the beach.
Explain how a sand spit is formed.
When there is a bend in the coastline, longshore drift carries the sand beyond the bend to form a sand spit.
Behind it sheltered water becomes a marsh.
The end of the spit is curved where it meets strong winds and waves.
How is a bar formed?
After a spit has been formed longshore drift may continue up the spit and join with the other end of the coastline forming a bar.
Give an example of a soft rock.
Clay.
What coastline is a soft rock coastline?
The holderness coast in Yorkshire.
What are the properties of a soft rock coast?
- high but less rigged and less steep than hard rock coasts
- piles of mud and clay on the face and at the bottom of cliff
- few hard rocks at foot of cliff
Give an example of a hard rock.
Granite
What is an example of a hard rock coast?
Land’s end, Cornwall
What are the properties of a hard rock coast?
- high, steep and rugged
- bare cliff face
- some rocks and boulders at foot of cliff
- has erosion features such as caves, arches and stacks.
Describe the formation of lulworth cove.
Waves slowly cut through a weakness in the band of limestone cause by a river cutting a valley through the limestone. This formed the entrance.
Waves eroded the soft band of clay fast.
The chalk behind the clay is more resistant so is currently eroding slower but the cove is still wording side ways.
What is a concordant coastline?
Where the same rock type runs along the coastline.
What is a discordant coastline?
Where the rock type alternates in bands along the coastline.
two land forms formed on a discordant coastline?
Headlands and bays.
How does rock type Effect coastal retreat?
Hard rocks erode more slowly than soft rocks.
How does the number of joints And faults effect coastal retreat?
Rocks with more faults and joints erode more quickly thank rocks with fewer joints and faults.
How does fetch effect coastal retreat?
If the wind blows over a wide area of sea(fetch), the waves are stronger and will have a greater impact on the cliffs.
How does cliff exposure effect coastal retreat?
Cliffs exposed to strong wind and weather will erode more quickly than sheltered cliffs.
How do storms effect coastal retreat?
Cliffs exposed to frequent storms will erode more quickly.
How do sea defences affect coastal retreat?
Some cliffs are protected by sea defences which slow retreat down.
List the consequences of coastal erosion.
Houses destroyed Farmland lost Hotels and caravan parks abandoned Loss of roads Loss of income
Positive and negative of a sea wall?
+protects cliff and buildings
-expensive
Positive and negative of groynes?
+prevents sea removing sand
-exposes other areas of coastline
Positive and negative of rip rap?
+rocks absorb wave energy
-expensive
Positive and negative of off-shore reef?
+waves break on reef and lose power
-expensive and interfere with fishing
Positive and negative of beach replenishment?
+sand reduces wave energy and maintains tourism
-expensive
Positive and negative of managed retreat?
+people and activities avoid erosion by moving inland
-expensive
Positive and negative of cliff regrading?
+reduces slippage
-foot of cliff isn’t protected from waves
How fast is the holderness coast retreating?
2m every year
What are the management strategies for the holderness coast?
Groynes and rock armour in mappleton.
Some areas are undefended.
How long is the holderness coast?
60km
Describe the process of hydraulic action.
Waves hitting the rock forces pockets of air into cracks. Trapped air, release quickly, breaks up the rock.
