Lesson 7 Flashcards
(49 cards)
What is long shore drift?
The prevailing wind causes waves to approach the coast at an angle. The swash carries the sediment up the beach at the same angle (45º). The backwash, however carries the material back down the beach at right angles as this is the steepest gradient. This causes sediment to be moved along the coast in a zig-zag pattern
What is lateral shift?
The net effect of movement up and down the beach (long shore drift)
What are the 4 types of transport?
Suspension
solution
traction
salutation
What is suspension?
Sediment floating due to it being very fine
What is solution?
Dissolved sediment carried along
What is salutation?
Pebbles bounced off each other
What is traction?
Large rocks rolled along the sea bed
What are tides?
Changes in the water level caused by gravitational pull of the moon.
What tides do we have in the UK?
2 high and 2 low
What is tidal range?
the difference between high and low tides
What is a high tidal range?
Strong tidal currents as the tides rise and fall.
Strongest near estuaries
What are sediment cells?
Sediment moves along the coast in these.
They act as a system.
What do sediment cells do?
In each cell sediment moves between beach, cliffs and sea through erosion, transportation and deposition.
Each cell operates between physical barriers that prevent sediment from moving further along the coast.
How many sediment cells does England and Wales have?
11
What happens if a sediment budget fails?
waves continue to transport sediment (positive feedback)
What happens if a sediment budget increases?
Sea deposits material as it can’t carry it (negative feedback)
What is the process of sediment cells called?
Dynamic equilibrium (state of balance between continuing processes)
What is a spit?
A stretch of sand or shingle extending from the mainland out to sea.
How is a spit formed? (7)
Develop when a sudden change in the shape of the coastline.
Sediment transported by longshore drift.
Longshore drift continues to transport material in the same direction rather than following the coastline.
Material transported out to sea.
Wind changes direction, waves alter direction.
Deposition inland.
The flow of water into the sea at an estuary is stronger than the drift, forcing the sediment to be deposited.
What is a recurved spit?
A spit which has changes as a result of wave refraction making the end of a spit curve it into a “hook”
What develops behind a spit?
A salt marsh
An example of a spit?
Spurn Head in Yorkshire
What is a beach?
Accumulation of material deposited between high and low tidal limits, which shelves downwards towards the sea.
Where is coastal material deposited?
Backshore and foreshore
