Coastal Zones Flashcards
Define Weathering
Disintegration or decay of rocks from their original place
Breakdown of material
Define Erosion
Disintegration or decay of material anywhere through movement, contact or water
Removal of rocks
Describe 3 characteristics of destructive waves
Erode the coast
Weak Swash
Strong backwash
[ High amplitude and short wavelength]
Describe 3 characteristics of constructive waves
Create beaches
Strong Swash
Weak Backwash
[ Low amplitude and long wavelength]
Describe Biological Weathering
Actions of plants and animals, for example plant roots expanding in cracks, plants growing in the cliff and animals burrowing.
Describe Chemical Weathering
Slightly acidic rain erodes rock like limestone, dissolves it away
Describe Physical Weathering
Freeze thaw weathering - Water expanding in gaps and making them larger
Exfoliation - Rocks expanding and contracting which causes the outer layer to flake off
Describe the process of long shore drift
Waves approach the coast at an angle because of wind
Swash deposits material at the same angle
Backwash takes it back at perpendicular angle because of gravity
The zig zag movement causes movement of sediment along the beach
Why does deposition occur in bays
The water has to travel further so it looses energy and deposits the material in the bay
Define a concordant bay
Layers of hard and soft rock parallel to coastline
Define discordant bay
Layers of hard and soft rock perpendicular to coastline
Define headland
A point of high land that juts out into the sea
Define bay
Broad coast inlet that often has a beach
Define wave cut platfotm
Smooth rock where the cliff used to be, often covered in sand
What is the sequence of erosion of a headland to a stump
Crack/Crevice Cave Arch Stack Stump
Define beach
Area of deposited sediment on the coast between mainland and the sea
Sandy beaches are found in sheltered bay
Define Wave diffraction
The waves spreading out as they pass through two headlands, reducing energy and increasing deposition
Define spit
A narrow area of land extending into the sea from deposited sediment from long shore drift
Define bar
Spit formed across a bay trapping water and causing a lagoon
Give 3 causes of rising sea level and coastal flooding
Global warming and expansion of water particles
Storm Surges
Sun and Moon in alignment causes high tide in the spring
Give the 3 dune names
Embryo dunes
Yellow/Grey Dunes
Mature dunes
Give 4 conditions of a sand dune ecosystem
Extreme arid conditions
Alkaline conditions
Prevailing winds
Exposed large area
Define concordant coast
Geology parallel to coast
Define discordant coast
Geology perpendicular to coast
Define Corrosion
Chemical Weathering especially limestone
Define Hydraulic Action
Sheer force of the waves
Define Cavitation
Air forced into cracks by water making it bigger
Define Abrasion
Suspending particles making waves more erosive
How are sand dunes formed?
Sand is deposited on the beach by long-shore drift, and the wind blows the sand onto the land
Sand dries between periods of high and low tide and is trapped in plants like seaweed forming a dune.
Define Swash
Movement of water up the beach at an angle, determined by prevailing winds
Define Backwash
Movement of water back down the beach into the sea at a right angle to the coast, determined by gravity
Give 3 factors effecting the size of a wave
Strength of the wind
How long the wind blows for
Length of water the wind blows over (fetch)
How are waves formed?
Air pressure creates waves
Friction between the water and the beach causes the wave to slow down causing the wave to break
Define Mass Movement
Downhill movement of material under the influence of gravity.
Give 3 examples of Mass Movement
Rockfalls
Rotational Slip
Landslide
Give 3 times when deposition occurs
Constructive waves when swash is dominant
Sheltered area in a bay between two headlands
Weak currents
