COASTS definitions Flashcards
Abrasion
A form of erosion where loose material and sediment ‘sandpapers’ the walls and floors of the river, cliff or glacier. Also known as attrition
Backshore
The upper beach closest to the land, including any cliffs or sand dunes
Bar
A section of sand caused by deposition. They all Join two side of a bay together, creating a lagoon behind the bar.
Beach morphology
The surface shape of the beach
Beach nourishment
The addition of sand and sediment to an eroding beach by human. The new material will be eroded by the sea which saved the cliffs or sand dunes from erosion and recession
Coastal recession
The retreat of a coastline due to erosion, sea-level rise or submergence
Concordant (parallel ) coastline
A coastline where band of alternate geology run parallel to the coast
Corrasion
A form of mechanical erosion where arterial and sediment in the sea is flung at the cliff face as waves break against it, this breaks up the rock making up the cliff.
Corrosion
The weak acid in seawater and some types of seaweed react it’s particular rock minerals, causing erosion and weakening
Discordant (perpendicular) coast
A coastline where bands of alternate geology run perpendicular to the shore
Dynamic equilibrium
A system where its input and outputs are in balance. Short term changes can affect this balance, negative feedback loops help to take the system back to dynamic equilibrium
Emergent coast
A coastline thats is advancing relative to the sea level at the time
Estuary
The point as where the river meets an ocean, often muddy. Sometimes estuaries become exposes at low tide or hazardous to traverse in a boat due to sandbanks
Fetch
The length of water over which the wind has travelled
Foreshore
The lower part if the beach covered twice a day at high tide ( the past of the beach that receives the more regular wave action )
Freeze thaw
A form of physical sub-aerial weathering where water freezes i the cracks of a rock expands and enlarges the crack. This weakens the rock overtime leaving it more open to erosion
Geology
The physical structure and arrangement of a rock
Glacial Erosion
The removal of loose material by glacer ice, involving abrasion etc
Groyne
A from of hard engineering. Low-lying concrete or wooden walls, constructed perpendicular to the seafront and run out to sea. They encourage the trapping of sediment to reduce erosion caused by longshoreman drift or by winds
Hard management
The use of concrete structure to reduce or halt the recession of a coastline. It incudes: groyne, sea wall and rock armour
High-energy environment
A coast where wave action is predominantly large destructive waves, causing much erosion
Hydraulic action
The pressure of compressed air forced into cracks in a rock face will cause the rocks to weaken and break apart
Impermeable
A rock that changes in sea level due to a change in local coastline or land height
Isosatic
A local change in sea level due to a change in a coal coastline or land height
Littoral cell
An area of coastline which has all sediment processes occur ing sources, transport and sinks A littoral cell is not a closed system
Longshore drift
The transportation of sediment along a beach. Longshore drift is determined by the direction of the prevailing wind
Low energy environment
A coast where wave action is predominantly small constructive waves. Deposition usually takes place leading to beach accretion (growth)
Mass movement
Where there is a large downhill move to of material usually from a cliff face. Here the rock is often weak due to erosion and the move to is caused by gravity
Nearshore
The area before the shore where the waves steepness and breaks before they reach the shore and then reform before breaking on the beach. It extends from the low-tide zone and then out to sea
Permeable
A rock that allows water to pass through it
Plant succession
Change to a plant community over time due to adaptation to changing growing conditions e.g sand dune and salt marshes
Rock armour
Large rocks or concrete blocks used as barricades to reduce marine erosion at the base of cliffs
Saltation
A form of transportation where smaller sediments bounces along the sae bed pushed by currents. This sediment is to heavy to be picked up by the flow of water
Salt marsh
In sheltered bays or behind spits, salt and minerals will build up. Vegetation may establishes, further stabilising the marsh
Sand dune
A depositional landform, where sand and sediment build up around driftwood and accumulate over time
Sea wall
A hard management coastal defence where a concrete wall is built parallel to the seafront to redirect the energy of waves away from sensitive cliffs or the edge of a coastal town
Sediment cell
Sections of the coast borders by prominent headlands, within these sections, movement of sediment is almost contained and the flows fo sediment should act in Dynamic equilibrium
Sediment budget
Use of inputs, outputs, stores and transfers to assess the gains and losses of sediment within a sediment cell
Soft management
The use of natural arterials and environmentally sustainable approaches to reduce coastal recession. Include: beach nourishment, managed retreat, sand dune encouragement
Spit
A long depositional landform formed for sand and shingle
Sub aerial processes
The combination of mass movement and weathering that affects the coastal land above sea
Submergent coast
A coast that is sinking relative to the sea level of the time
Tombola
A spit joining the mainland to an island
Wave quarrying
When air is trapped and compressed against a cliff which causes rock fragments to break off the cliff over time
Wave cut notch
Formed by erosional process such as abrasion and hydraulic action. It is a dent in the cliff usually at sea level of high tide
Wave cut platform
Is the narrow flat are often found at the base of a sea cliff or along the shoreline of a lake, bay or sea that as been created by erosion
Cave
Formed where notches and weaknesses are widened and depend on wave where there is a weakness in the cliff face
Geo
Long narrow gorge like inlet (small arm of sea, lake or river) caused by collapse of a cave roof
Blow hole
Vertical shafts linked to the sea through caves at the lower end and coming out to the cliff top cause by waves blasting trough lines of the weakeness
Arch
Formed by wearing away of narrow headlands, especially when there is back to back formation of caves. There are temporary and eventually collapse
Stacks
Fall isolated pillars, free -standing in the sea occur alone or in groups, result form the collapse of an arch
Stump
Small rocky platform offshore may be covered at high tides formed by undermining of stacks causing their collapse
Differential erosion
Different rates of erosion that occur along a coastline du to geological factors such as resistance of rock and structural weaknesses.
Adaptation
Making changes to lessen the imoact of flooding. This can include building sea wall, building surge storm barriers( Netherlands), reinstating mangrove forets ( Siri Lanka)
Mitigation
Making effort to reduce the emission of green house gases to reduce impacts of climate change, finding alternatives: renewable energy etc
