Coasts Flashcards
(26 cards)
Why is the coast a multi-use area?
It provides economic, environmental and recreational opportunities.
Why are coral reefs important?
- homes for sea creatures
- bio-diverse - some species can only survive there
- nutrient-rich water
- main source of energy for reef wilflife
- shelter
- tourist attraction
- coastal defence
- scientific research
What are the threats to coral reefs?
- tourists damaging the area
- increase in sediment levels
- explosive fishing
- development
- global warming
- pollution
Name 5 types of erosion.
1) Wetting/drying
2) Abrasion
3) Hydrolic action
4) Corrosion
5) Attrition
Name 4 types of weathering.
1) Freeze-thaw
2) Onion-skin
3) Biological
4) Chemical
What is wetting/drying?
1) Soft rocks get wet and expand
2) Contract when dry
3) Weakens the rock over time
What is abrasion?
Caused by rocks in the sea hitting cliffs.
What is hydrolic action?
Caused by the force of waves.
What is corrosion?
Sea water dissolves soluble material along the rock face.
What is attrition?
Rocks and boulders hit each other in the sea and break apart.
What is freeze-thaw weathering?
1) Water gets into cracks
2) The water freezes and expands
3) The cracks get bigger and the rocks break
What is onion-skin weathering?
Rocks being constantly heated and cooled, causing the surface to peel away.
What is biological weathering?
Weathering caused by plants or animals, e.g. tree roots.
What is chemical weathering?
Weathering caused by chemicals, e.g. acid rain.
What is a consructive wave?
- long, low waves
- strong swash, weak back wash
- allows the beach to build up
- limited errosion
What is a destructive wave?
- short, steep waves
- strong back wash, weaker swash
- eroded material removed by waves
How are bays and headlands formed?
Different rocks erode at different speeds. A strip of soft rock with hard rock either side will erode so that a bay is formed where the soft rock is eroded quickly and headlands where the hard rock erodes slowly.
What is cliff slumping?
- Soft rock is eroded by waves as the base of the cliff to form a wave-cut notch.
- Clay becomes saturated and forms slip planes.
- The weight of the saturated cliff causes it to slump.
How are spits formed?
When the energy of the river meets the energy of the sea the material it was carrying is deposited.
What are swash-aligned beaches?
- waves approach at 90 degrees to the beach
- have a smooth profile
What are drift-aligned beaches?
- waves approach at an angle
- much more common
How is sediment transported along the cost?
Long-shore drift.
What is a tombolo?
When a spit connects the mainland to an island, e.g. chesil beach.
What is a bar?
A bar connects a mainland to another mainland.
