Paper 2: Coastal Change and Conflict Flashcards
What is a concordant coastline?
Where bands of soft and hard rock run parallel to the coastline
What is a discordant coastline?
Where bands of soft and hard rock run perpendicular to the coastline
How do waves form?
Wind blowing over bodies of water
What does the size of the wave depend on?
How long the wind has been blowing, how strong the wind is, how far the wave has travelled (the fetch)
What is the fetch of a wave?
How far it has travelled
What is the swash?
The movement of water as it rushes up the beach from the sea at an angle
What is the backwash?
When water runs back down the beach
What is a constructive wave?
It causes deposition, common in summer, low frequency (8-10/m)
What is a destructive wave?
It erodes the coast, common in winter, high frequency (10-14/m)
What is erosion?
The wearing away or removal of material by water
What is transportation?
The movement of material by water
What is deposition?
The dropping of material by water
What is hydraulic action?
Water is forced into the cracks in rocks. This compresses the air. When the wave retreats, the air blasts out, forcing the rock apart.
What is coastal abrasion?
Sediment is thrown against the cliff by waves. This wears the cliff away and chips bits of rock off the cliff.
What is coastal attrition?
Loose sediment knocked off the cliff is swirled around by waves. It collided with other sediment and is worn down, becoming smaller and rounder.
How are headlands and bays formed?
The bands of rock run perpendicular to a discordant coastline. The soft rock erodes faster than the hard rock due to hydraulic action of destructive waves. Bays are formed from soft rock and headlands and formed from hard hard rock.
How are coves formed?
The bands of rock run parallel to a concordant coastline. An area of weakness is found in the hard rock. Erosion such as hydraulic action and abrasion occur at the weakness. Once the hard rock has eroded, the soft rock behind erodes much faster, therefore forming a big empty area, known as a cove.
How are wave cut platforms formed?
Destructive waves erode the cliff through processes such as abrasion. Waves erode the cliff between the high and low tide lines. Over time, this erosion creates a wave cut notch. This notch gradually gets larger and the wave cut notch is left unsupported. Mass movement occurs as a result of gravity and the cliff retreats. The process starts to repeat with a new notch forming. The cliff continues to repeat.
What kind of profile do sandy beaches have?
Gentle profiles
How are sandy beaches formed?
Deposition
What kind of profile do pebble beaches have?
Steep profiles
How are pebble beaches formed?
Cliffs being eroded
What is a spit?
An extended stretch of sand or shingle jutting out into the sea from the land
How is a spit formed?
By longshore drift
What is a bar?
When a spit has grown across a bay and traps a lagoon behind it
How is a bar formed?
By longshore drift
How are lagoons formed?
When an area of water is cut off by a bar. They can be covered up by sediment over time.
What is longshore drift?
The zigzag movement of sediment along the coastline
How is sediment transported by longshore drift?
The prevailing wind makes the waves move onto the beach at an angle. The swash follows this direction and transports and then deposits sediment onto the beach at a 90 degree angle. Gravity then causes the backwash to transport and deposit sediment into the ocean. This then repeats along the shoreline, creating a zigzag pattern. The sediment is transported and deposited further along the coastline.