Coastal Zone Flashcards
What causes waves?
The wind
What are the 2 types of waves?
Constructive and destructive
What is swash and backwash?
Swash is the movement of the wave towards the beach.
Backwash is the movement of the wave away from the beach.
What are the characteristics of constructive waves? (4)
- Swash is stronger than the backwash
- Low wave in proportion to length
- Deposition - builds beaches
- Most common in summer
What are the characteristics of destructive waves? (4)
- Backwash is stronger than the swash
- High wave in proportion to length
- Carries rocks/sand back to sea
- Most common in winter
What are the different types of weathering?
- Physical weathering
- Freeze-thaw weathering
- Exfoliation
- Chemical weathering
- Biological weathering
Explain freeze-thaw weathering
- Water collects in cracks/holes
- At night the water freezes and expands
- This widens the cracks in the rock
- The ice melts and refreezes over and over again
Explain exfoliation
- Found where there are large temperature variations
- Heating and cooling of a rock causes the rock to expand and contract
- Eventually the outer layer flakes off
Explain chemical weathering
Rain reacts with and dissolves rocks such as limestone and chalk
Explain biological weathering
The actions of plants and animals. Plant roots grow in rocks and expanding cracks. Rabbits digging into weak rocks
What is mass movement?
Downhill movement of material under the influence of gravity
Give some examples of mass movement? (4)
- Rockfalls
- Mud-flows
- Rotational slip
- Landslide
What are the proceses of coastal erosion? (4)
- Hydraulic action (force of the water hitting the cliffs)
- Abrasion (waves pick up loose stones and throw them against the cliff)
- Attrition (materials hit each other and become smaller and rounder over time)
- Solution (certain rocks being eroded from the sea water)
What are the processes of coastal transport? (4)
- Traction (big boulders roll)
- Saltation (smaller pebbles bounce along sea bed)
- Suspension (lighter particles are suspended in the water
- Solution (chemicals are dissolved in the water)
What is longshore drift?
The movement of material down the coast by waves
What angle do waves hit the beach?
45º
What angle do waves move away from a beach?
90º - perpendicular
What is a headland?
A bit of land that juts out to sea