The Coastal Zone Flashcards
Weathering
The breakdown of rocks in situ (in their original location without them being moved away). This produces finer particles that can then be removed away by mass movement, transportation and erosion
Mechanical weathering
Sometimes called physical weathering – it is the breakdown of the rock without any changes to the minerals that form the rock (includes freeze-thaw and exfoliation)
Freeze-thaw weathering
Sometimes called frost shattering. Water enters a crack or joint in a rock, freezes and expands exerting pressure on the rock. Repeated freeze and thawing eventually shatters the rock.
Exfoliation
Sometimes called onion-skin weathering. In hot, dry climates the outer layers of rock heat up quicker than the inner layers. Repeated heating and cooling peels off the outer layers.
Chemical weathering
When the rock’s mineral composition is changed, leading to the disintegration of the rock. Occurs mostly in moist, warm environments.
Carbonation
The dissolving of limestone with carbonic acid (found in rainwater).
Biological weathering
Caused by plants and animals – they speed up mechanical weathering with their roots and burrowing. Organic acids released by organisms may also speed up chemical weathering.
Mass movement
The movement of sediment downhill under gravity
Land slides
The sliding of areas of land downhill under gravity (often in areas of layer cake geology e.g. Lyme Regis)
Mudflows
The flowing and sliding of unconsolidated sediment downhill under gravity
Soil creep
The slow, steady movement of top soil downhill under gravity
Rock falls
The quick, sudden falling of rock downhill under gravity (often caused by freeze-thaw)
Constructive waves
Waves that lead to deposition (they have long wavelength, low height, strong swash, weak backwash, less frequent and break gently)
Deconstructive waves
Waves that lead to erosion (they have short wavelength, high height, weak swash, strong backwash, scouring action, frequent)
Fetch
The distance the wind has blown over the sea. Long fetch creates strong destructive waves.
Erosion
The breakdown of sediment by moving forces. Done by destructive waves.
Hydraulic action (or hydraulic power)
The power and weight of the water breaking against the coastline.
Abrasion
The breaking waves throw sand and sediment against the cliff face.
Attrition
Particles carried in the wave rub against each other and are worn down.
Corrosion
The action of acids and salts in sea water corroding the cliff face.
Transportation
The movement of sediment from one place to another.
Longshore drift
Movement of sediment in a zig-zag pattern up and down the shore with the swash and backwash. The direction of longshore drift is dictated by the direction of the prevailing wind.
Traction
The rolling of larger boulders on the seabed.
Saltation
The bouncing of smaller boulders on the seabed.
Suspension
When sediment is carried in the body of water.
Solution
When sediment is dissolved in the water.
Deposition
The dumping of the sediment load carried in the waves. Done by constructive waves.
Landform of erosion
Landforms created by the erosive power of destructive waves (e.g. headlands and bays, cliffs, wave cut notches, wave cut notches platforms, caves, arches, stacks and stumps).
