Gcse- Coasts Flashcards
What is the coast?
Narrow contact zone between land and sea, which is constantly changing due to effects of land, air and marine processes.
How are waves created?
They are created by transfer of energy from wind over the surface of the sea.
What is the fetch?
The maximum distance of water over which winds can blow.
What happens when wave reaches shallow water?
The velocity at its base will be slowed down due to friction. But the top of the wave is unaffected by friction, it becomes higher and steeped until it breaks.
What does swash do?
Transfers energy up the beach
What does backswash do?
Returns energy down the beach
What are the 2 different types of wave?
Constructive- have limited energy. Most used by swash to transport energy up beach.
Destructive- have more energy. Most of this used by backswash to transport material.
Different types of erosion-
4 different processes-
Corrasion- cause by large waves hurling beach material against cliff
Attrition- when waves cause rocks and boulders on beach to hit eachother.
Corrosion- when salts and other acids in water dissolve into cliff
Hydraulic pressure- force of waves compressing air into crack in cliff
How are headlands and bats formed?
Form along coastline where there is alternating outcrops of harder and softer rock. Destructive waves erode areas of softer rock a lot quicker to form bays. Waves can’t wear away resistant rock as quick, so headlands are left protruding to sea.
How is a wave cut notch formed?
Wave erosion is at its greatest when wave breaks at bottom of cliff. Waves under cut foot of cliff to form a wave cut notch.
Cave- arch- stack process
Cliff more likely to form where coastline consists of resistant rock. Corrasion and corrosion by waves widen weakness’. Weakness’ firstly form a cave. If cave forms at headland, cave might widen and deepen to form a natural arch. Waves continue to erode foot of arch until roof becomes too heavy to be supported. Roof collapses and leaves a stack. In time further wave action results in stack collapsing to leave a stump.
What is transportation?
Major movement along coast of material by long shore drift. Waves approach beach in direction in which wind blows. When wave breaks , swash carries material up beach. As swash dies backswash returns material down beach at right angle to water. Material is slowly moved along coast.
What is deposition?
Sand and shingle transported along coast by long shore drift, in time will reach area where water is sheltered and waves lack energy. Material may temporarily be deposited to form beach. Beaches aren’t permanent because they can change shape.
What is a spit?
Permanent landform resulting from marine deposition. It is a long narrow accumulation of sand with one end attached to land and other end into the sea. Form where long shore drift moves large amount of sand along the coast. During time material at end of spit may be pushed inland from curved end. Spit becomes permanent when sand is blown up the beach to form sand dunes.
Effects of cliff erosion-
Destroys buildings when cliffs collapse.
Holderness coastline is retreating by an average of 2m a year.
50 villages mentioned in doomsday book of 1066 have been lost at sea.
