Coastal Landscapes and Change Flashcards
What are rocky coastlines
Cliffs varying in height from a few meters to hundreds of meters; cliffs are formed from rock but the hardness of the rock varies
What are coastal plains
Land gradually slopes towards the sea across an area of deposited sediment, with sand dunes and mud flats being the most common example
What are joints
These divide rock strata up in blocks with a regular shape
What are fissures
Smaller cracks in rocks. often they are only a fe cms long
What is a fault
A major line of weakness within the rock. This causes large fractures
What 3 factors affect wave size
Fetch
Strength of wind and how long its been blowing for
Depth of water
What is a concordant coast
These coastlines have alternating layers of hard and soft rock that run parallel to the coast
What is a discordant coast
Coasts have alternating layers of hard and soft rock that are perpendicular to the coast
What are the 4 dips of cliff profiles
Horizontal dip
Seaward dip (High angle)
Seaward dip (Low angle)
Landward dip
What does the dip profile show
How the angle of the cliff dip profile can cause erosion to occur at different rates along the coastline
What is a constructive wave
Has a swash that is stronger than the backwash. This therefore builds up the coast
What are destructive waves
Has a backwash that is stronger than the swash. This therefore erodes the coast
How does vegetation stabilise sediment
Roots bind sediment together
Provides a protective layer to prevent exposure
Protection from wind erosion
Depositional features at a bayhead beach
Waves break at 90 degrees to the shoreline and moves sediment into a bay
Depositional features of a tombolo
A sand or shingle bar that links the coastline to an offshore island
Depositional features of a barrier beach/bar
A sand or shingle beach connecting two areas of land with a lagoon behind
Depositional features of a cuspate foreland
Triangular-shaped features extending out from a shoreline
What are the 3 Types of geology
Sedimentary
Igneous
Metamorphic
What is attrition
Rocks that bash together to become smooth/smaller
What is Solution
A chemical reaction that dissolved rocks
What is abrasion
Rocks hurled at the base of a cliff to break pieces apart
What is Hydraulic action
Water enters cracks in the cliff, air compresses, causing the crack to expand
What is erosion
Breaking down and removal of material by the movement of wind and water
What is suspension
Sediment is carried along in the flow of the water
What is saltation
Pebbles that bounce along the seabed
What is Traction
Boulders that roll along a seabed by the force of the flowing water
What are the 4 types of erosion
Attrition
Solution
Abrasion
Hydraulic action
What are the 4 types of transportation
Solution
Suspension
Saltation
Traction
What are Synclines
A downward, U-shaped fold in the layers of rock in the Earths surface
What’s a Anticline
An upward, curved fold in the layers of rock in the Earths surface
What is weathering
An alteration or breakdown of rock when they are exposed to the atmosphere
What’s the 3 types of weathering
Carbonation
Mechanical
Biological
What is a sedimentary rock
Weathering and erosion of rocks exposed at the surface e.g sandstone
What is a metamorphic rock
Rocks under high temperatures and pressures change composition e.g slate
What is a igneous rock
Formed by the cooling and solidifying of molten rock e.g granite
Examples of hard engineering defences
Groynes
Sea walls
Rip rap
Gabions
Examples of soft engineering defences
Beach nourishment
Managed retreat
Benefits of hard engineering
Quick/one-off solution
Reassure coastal communities security of properties
Reduce insurance costs of homes
Negatives of hard engineering
Cost very high and requires maintenance
Unattractive and unappealing to tourists
Needs of environment often overlooked
Positives if soft engineering
Low cost
Less impact on environment
Natural appearance
Negatives of soft engineering
Regular maintenance
Less effective against extreme storm events
May have to compensate for property loss
What are isostatic changes
Local changes in land and sea levels
What are eustatic changes
Worldwide changes in sea levels
What are emergent coastlines
Formed as a result of a fall in sea level
What are raised beaches
As coastline rises (or sea level falls) beaches which were once at sea level are left high up in the cliffs
What are relict cliffs
Caves, arches and stacks formed when they were at sea level are now left high up on the cliff face today
Causes of coastal flooding
- Severe weather events drive up water level, creating a storm surge such as hurricanes
- Large waves (driven by local winds or swell from distant storms, raise coastal water levels which creates large waves)
- Flooding from storm surge combine with river flooding from rain in upland water shed
- When a severe storm hits during high tide, risk of flood increases
- Flooding from a
What is a sediment cell
A section of coast that has been controlled for management purposes (where shingle and sandstone is contains and regulated to keep a healthy sediment budget )
What is a sediment budget
Amount of sediment available within a sediment cell
What is carbonation weathering
Breakdown of rock by changing its chemical composition
What is mechanical weathering
A physical change caused by the movement of water or wind
What is biological weathering
Rocks that have been broken down by living organisms
