Coastal Landscapes and Change Flashcards
Define abrasion
When rock particles are gradually worn down by impact against other rocks, making pebbles smaller
Define adaptation
To change to suit the environment
Define ‘advance the line’
A management strategy where the aim is to make the coast advance into the sea.
Define arch
When a cave punches through a headland e.g. Durdle Door
Define attrition
When waves hurl sand and pebbles at a cliff, gradually chipping away at the rock and wearing it down
Define backshore
A part of the littoral zone that is furthest from the sea and usually above the influence of the waves
Define barrier beach
A ridge of sediment running parallel to the shore formed by deposition, blocking off the entrance into a lagoon
Define beach nourishment
When sediment is put on a beach after it has experienced increased erosion.
Define bedding planes
Natural breaks in strata representing time gaps between periods of rock formation
Define berm
A terrace on a beach formed backshore above water level at high tide
Define biological weathering
When living plants or animals work to gradually break apart rock and wear it down
Define carbonation
A form of chemical weathering where weak carbonic acids work to dissolve rocks like limestone and chalk
Describe boulder clay
Very soft geology that is found on the Holderness Coast and erodes very quickly
Define blowhole
Created when a cave manages to break through to the top of the cliff and sea water and spray bursts out when the cliff is hit by powerful waves.
Define cave
A microfeature which forms the start of the sequence that results in stump formation, often caused by weathering and erosion .
Define chemical weathering
When chemical processes such as carbonation and oxidation act to gradually wear down rocks
Define cliff profile
The height and angle of a cliff face and its features
Define cliff regrading/drainage
When water is taken out of cliffs to stabilise them
Define climax community
A stable and balanced ecosystem where species and their interactions are adapted to the environment, formed after succession.
Define coastal morphology
shape of the coast
Define coastal recession
The retreat of a coastline due to erosion, sea-level rise or submergence.
Define corrosion
A type of marine action where alkaline rocks such as chalk and limestone are vulnerable to solution by weak acids found in sea water.
Define concordant coast
Alternate bands of more or less resistant rock running parallel to the coast
Define constructive wave
A gentle wave with low height, long wavelength and low frequency.
They are associated with deposition due to their strong swash and weak backwash.
Define cost benefit analysis
A process used to measure benefits of a project vs the costs to see how good a decision it would be
Define cuspate foreland
Triangular features extending out from the shoreline formed when two spits which follow different LSD join
Define destructive wave
A powerful tall wave with short wavelength and high frequency.
They are associated with erosion due to their strong backwash and weak swash.
Define Dalmatian coast
A type of concordant coast associated with rising sea levels which submerged a series of valleys and ridges, parallel to the coast
E.g. Croatia
Define differential erosion
When less resistant rock erodes faster to form headlands and bays
Define discordant coast
Alternate bands of more or less resistant rock running at a right angle to the coast.
Define ‘do nothing’
A management strategy where no defences are made and allows the ocean to erode the coast
Define aligned beach
Beaches aligned with the direction of longshore drift
Define stabilisation
When species like marram grass are planted on sand dunes to stabilise the sediment and helps trap it so they can build more
Define dynamic equilibrium
The tendency towards a natural state of balance within a cycle
Define emergent coastline
Landforms created due to relative fall in sea level
Define an ‘Environmental Impact Assessment’
An assessment technique that aims to anticipate the impacts of a project
Define environmental refugee
When a person is forced to leave their homes due to a change to the environment such as sea level rise or flooding
Define eustatic change
The rise or fall of global sea level relatove to land due to thermal expansion or melting of sea ice
(ocean go up down, land stay still)
Define faults
Formed when stress on the rock exceeds its strength and causes it to fracture and split along a fault plane
Define fetch
The distance over which wind is blown, causing waves
Define fjords
A drowned glacial valley with very steep sides and deep water
Define folds
Formed by pressure during tectonic activity causing rocks to crumple, especially when less resistant e.g. Lulworth Crumple
Define freeze-thaw weathering
When water gets into a fracture in rocks, freezes and expands in volume, causing the fracture to widen, eventually breaking it.
Define geology
Type of rock and its chemical properties
Define groyne
vertical stone or timber structures built at a 90 degree angle to the coast to trap sediment
Define Haff coast
A concordant coastline with a spit with lagoons parallel to the coast
Define halophytes
Salt marsh pioneer plants which are very salt tolerant e.g. cordgrass
Define halosere
The salt marsh plant succession overtime as a whole
Define hard engineering
Long term physical structures, usually expensive
Define headlands and bays
Bays are when less resistant rock is eroded faster, while headlands are left behind due to being more resistant
Define high energy coastline
Also known as rocky coasts
Typically, rocky and steep, experiences powerful waves that form erosional landforms
E.g. Hangman’s Cliff in Devon
8% of UK coastline is cliffs
Define ‘hold the line’
A management strategy which focuses on keeping the coast where it is
Define impermeable
Water cannot pass through
Define hydraulic action
A type of marine action which erodes the cliff due to the sheer power of the waves forcing air into the cracks, which expand as the waves recede, causing them to widen and the cliff to weaken
Define ICZM
Integrated Coastal Zone Management - Plans defences while looking at the whole coast and manages them fairly
Define isostatic change
Local rise or fall of land level relative to the sea due to presence or absence of weight on land due to glacial ice or accretion
(Land move up down, ocean stays)
Isostatic recovery/subsidence
The change in land level where land is compressed and sinks due to the weight of ice or sediment or when it rebounds after this ice melts
Define joints
Vertical cracks caused by contraction of rock or by tectonic forces during uplift
Define lithology
The physical characteristics of a rock
Define littoral zone
The zone between land and sea, includes backshore, foreshore, nearshore and offshore
Define longshore drift
Transportation of sediment due to waves approaching the coast at an angle of the prevailing winds, swash carries the material along
Define low energy coastline
Also known as coastal plains.
Sheltered coasts with limited fetch and low wind speeds, making waves smaller
E.g. sand dunes, salt marshes, estuaries
Define ‘managed retreat’
A management strategy which focuses on flooding low lying coastal areas in a controlled manner
Define mass movement
A type of sub-aerial action where rocks, sand, soul etc move downslope under the influence of gravity
Define mechanical weathering
Processes that break up cliffs using physical force
Define mitigation
To reduce or prevent the effects of an event
Define mudflow
Unconsolidated soil becomes saturated by heavy rain which can cause the top layer to flow off the cliff
Define offshore
The area of a coast that is beyond the influence of waves
Define nearshore
The wave breaker zone
Define offshore bar
A submerged or partially exposed ridge of sand/sediment that is built by offshore waves
Define offshore breakwater
Walls built parallel to the shoreline offshore which dampen energy of waves reaching protected coastlines
Define permeable
The ability for fluids to flow through a rock
Define plant succession
The process of vegetation stabilising dynamic depositional features like sand dunes from colonisation of pioneer species to a climax community
Define pioneer species
Plants that are able to cope with harsh conditions such as water shortages and highly saline conditions. They are the first to grow on sand dunes and salt marshes.
Define polder
Low lying land that was reclaimed from a body of water