Coasts EQ2 Flashcards
What is a fetch?
The distance over which the wind has blown
How are waves formed?
Usually formed from friction between the wind and the surface, creating swells. The energy from the wind causes water particles to rotate inside the swell, moving the wave forward
Describe a constructive wave
Strong smash, weak backwash, gentle waves that deposit sediment, creating berms, long wavelength
Describe a destructive wave
Weak smash, strong backwash, wave energy is not absorbed by the beach so the base of the cliff is attacked, high waves, short wavelength
What is beach morphology?
The shape and features of a beach and the type of sediment of a beach
Describe a summer beach profile
Steep beaches, berms build up, backwash is weaker so there is sediment build-up
Describe a winter beach profile
High frequency waves, berms erode quickly, strong backwash transports sediment offshore
Describe the process of hydraulic action
Fast flowing water is forced into cracks, breaking up the banks over time
Describe the process of solution
When water dissolves certain types of rock such as limestone
Describe the process of attrition
Rocks and stones knock together, making them smoother
Describe the process of abrasion
Sand and pebbles are dragged along the seabed, wearing them away over time
What is a blowhole?
A hole formed at the top of a cave by coastal erosion as an opening for water pressure
How is a wave-cut notch formed?
When waves erode the base of a cliff, creating a notch. This leads to the cliff above the notch collapsing due to a lack of support. This process repeats as the cliff retreats as the coast erodes
How is a wave-cut platform formed?
After cliff recession occurs, the deposition of unsupported cliff creates a platform. As this platform grows, the waves must travel further to reach the cliff so it will eventually stop eroding or transporting material, therefore there is a limit to the size of a wave-cut platform
Explain how landforms are formed at a headland (cave, arch, stack, stump)
Large cracks are created due to hydraulic action, the cracks grow into a cave, the cave expands and breaks through the headland to create an arch. The arch is eroded and collapses leaving a stack. The stack is eroded to form a stump.
Explain how traction occurs
Sediment rolls along pushed by waves and currents
Explain how saltation occurs
Sediment bounces along because of the force of water or wind
Explain how suspension occurs
When sediment is carried in the water
Explain transport in solution
Dissolved materials are carried in the water as a solution
How does longshore drift occur?
As waves move, sediment is carried up the beach at an angle due to the prevailing wind. The backwash pulls this down perpendicular to the shore due to gravity. This transports sediment along the beach
What are offshore bars?
Partially or fully submerged ridges of sediment. As beaches are rowed, waves deposit the material offshore as bars
Where are beaches found and why?
Found in bays as wave refraction creates low-energy environments which lead to the deposition of sand or shingle
How are drift aligned beaches formed?
When waves break at an angle (LSD)
How are smash aligned beaches formed?
When waves break in line with the coast, creating concave beaches
What are tombolos?
Beaches formed between an island and the coast. Deposition occurs behind the island as wave energy is weak
What are cuspate forelands and how are they created?
Triangular-shaped headlands that expand from the coastline. They are created when LSD acts in opposite directions. As vegetation grows it stabilises the landform
What are barrier beaches?
Where a beach or spit extends across a bay to join headlands. This traps water behind forming lagoons
