Theme 2 - 2.3 - Coasts Flashcards
Define abrasion (or corrasion).
Rocks been thrown into the cliffs by waves and breaking off bits of the cliff.
Define hydraulic action.
This is when sea water and air get trapped in cracks. The increasing pressure of the water and air cause the rocks to crack.
Define solution (or corrosion).
The removal of chemical ions, which causes rock to dissolve.
Define attrition.
When rocks in the sea hit against each other, wearing themselves down.
Define fringing reef.
A reef that grow outwards around an island.
Define barrier reef.
A reef that is separated from the coast by a deep channel.
Define atoll.
A circular reef enclosing a shallow lagoon.
Define weathering.
The breakdown of rocks in situ (in place).
Define erosion.
The breakdown and removal of rock, involving the movement of the material by water, ice or wind.
What are the three main categories of weathering?
- Chemical
- Biological
- Physical/Mechanical
Define chemical weathering.
The break down of rocks caused by a change in their chemical make-up.
Define biological weathering.
Biological weathering is when flora and fauna break down the rock - E.g. growing roots systems or burrowing animals
(Biological weathering is sometimes included within physical weathering)
Define physical weathering.
The break down of rock caused by physical processes with no change in the rock’s chemical make up.
Name some marine processes which occur in coastal zones.
- Wave action from constructive and destructive waves
- Wind action
- Mass movement and weathering
- River and ice actions
What are marine processes?
Processes operating at a coastline that are connected with the sea, such as waves, tides and long shore drift.
What are the features of destructive waves?
- Short wavelength
- High height (>1m)
- High frequency (10-12/min)
- Backwash is stronger than swash
What are the features of constructive waves?
- Long wavelength
- Low height (<1m)
- Low frequency (6-8/min)
- Swash is stronger than backwash
What are the 4 processes of transportation?
- Traction - Dragging particles along sea floor
- Saltation - Smaller particles are bounced along
- Suspension - Fine particles are held up
- Solution - Sediment is dissolved
What are some reasons why deposition happens?
- Decrease in wave energy or velocity
- Large supply of material
- Irregular, indented coastline
How are waves formed?
Friction from the atmosphere (wind) causes a circular orbit in the water, which creates waves.
What causes waves to break?
The friction at the bottom of the waves slows the bottom down, meaning the top travels faster and causes the wave to eventually break.
What factors affect the size of waves?
- Fetch size
- Wind speed
- Wind duration
Which waves have more energy, constructive or destructive?
Destructive
What is the swash?
The pushing of a wave up the beach.