Coasts Flashcards
Fetch
Distance of open water which the wind can travel and transfer its energy to the surface of the water
Swash
As the water breaks from the wave and moves up the beach
Backwash
The drawing back of water down the beach due to gravity
Erosion
The wearing away and removal of rock
Types of erosion (5)
Hydraulic pressure Wave pounding Corrosion Corrasion/ abrasion Attrition
Hydraulic pressure
When air is trapped and compressed in a crack or gap in a cliff/ rock by a breaking wave
Wave pounding
The breaking of waves hits the foot of cliffs generating shock waves up to 30 tonnes
Corrasion/ abrasion
He wearing away of the cliff by sand and boulders hurled at them by the waves
Attrition
Rocks and boulders eroded from the cliff are broken down and rounded
Corrosion
The dissolving of rock by seawater that’s causes the rock to disintegrate
Weathering
Where rock is broken down in situ by natural processes
Types of weathering (3)
Physical
Chemical
Biological
Mass movement
When material moves down a slope due to the pull of gravity
Types of mass movement (2)
Soil creep
Slumping
Types of waves (2)
Destructive
Constructive
What are destructive waves (5)
Big strong waves Created by powerful wind, storms (long fetch) Erodes the coast Stronger backwash that swash High/ steep height, short wave length
What are constructive waves (5)
Not powerful waves Created by calm weather Builds up beaches Stronger swash than backwash Low height, long wavelength
Types of physical weathering (2)
Exfoliation
Freeze-thaw
What is exfoliation
A type of physical weathering
Rock structure is weakened by the heating and cooling of rock on the surface which then falls off
What is freeze-thaw
A type of physical weathering
Rock structure is weakened by water freezing and expanding and then melting in cracks of rock
What is chemical weathering
Acid rain either causes a chemical reaction or dissolves the structure to make the rock soluble so it is more easily broken down
Three types of biological weathering
Burrowing creatures break down structure of rock
Acids from bird/ animal excrement can chemically weather rock
Plants/ tree roots can break apart rock
What affects the rate of coastal erosion (5)
Type of wave Geology Fetch Weather/ season Rate of weathering
Erosion of a headland process
All due to wave pounding, hydraulic pressure and corrasion
Cave
Arch —> gets taller, top gets thinner, collapses
Stack
Stump
Formation of sea cliffs (4)
Waves erode at wave attack zone creating a wave cut notch
Overhang is unstable/ unsupported
Creates a wave cut platform and rock pools
Cliff retreats
How does the sea transport material?
Long shore drift
What is long shore drift
The movement of material up the beach due to the angle of the waves
Direction of waves/ swash is due to the direction of prevailing winds
Backwash us directly downwards due to gravity
What is a spit + example
Beach material that has extended past the mainland
Spurn Point, Holderness Coast
How are spits formed (3 steps)
Coastline has changed direction but direction of long shore drift stays the same
Material continues moving in the direction of longshore drift
Spit curves fur to secondary wind
What is a bar
When material is deposited and connected to another headland due to the direction of long shore drift and change in direction of the coastline
What is a tombolo
When the deposition is extended to an island due to direction of longshore drift and change in direction of the coastline
How are sand dunes formed (5)
Long stretch of sand generates constructive waves which deposit sand and pebbles
Onshore wind blows dried sand inland
Obstacles such as pebbles and small plants are covered by the sand
Sand is eroded from windward side and deposited on leeward side of dunes
Dunes move inland
Uses of sand dunes (5)
Leisure Tourism Education Off road driving Conservation
Case study of a place that attempts to restore sand dunes
Tynemouth Longsands
Case study for a place that manages coastal erosion
Holderness Coast
Mappleton-Rock armour for
Easington- Rock armour, large artificial platform
Why save mappleton from coastal erosion (4)
Tourist destination
Main road to coastline
Businesses
Houses
Why save Easington from coastal erosion (1)
Gas pipes from North Sea bring 25% national gas
Positives from saving Mappleton and Easington from coastal erosion (5)
Businesses are secure Residents have secure homes Employment at gas terminal People get gas Still tourism on beach
Negatives from saving Mappleton and Easington from coastal erosion
More erosion in areas without defence such as small farms and villages
Spurnhead is starved from beach material
Types of mass movement
Soil creep
Slumping
What is soil creep
Very slow movement due to gravity pulling on water stored In Soil
What is slumping
Larger scale faster mass movement.
Dry clays contract and crack so water fills these gaps and get absorbed
Becomes weak and unstable so slip down the cliff due to gravity
