1C: Coastal Landscapes in the UK Flashcards
What affects the strength of waves?
1) wind speed
2) length of time the wind has been blowing for
3) how far the wave has travelled
What is the fetch?
The distance the wave has travelled
Describe the formation and breaking of waves
1) wind blowing creates friction with the surface of the sea
2) water begins to move in a circular motion
3) friction with the sea bed slows the base of the wave
4) this causes the water to move in an elliptical motion
5) the top becomes higher and steeper until it breaks
Compare the wave height of constructive and destructive waves
Constructive waves have a smaller wave height (less than 1m)
Compare the wave length of constructive and destructive waves
Constructive waves have a larger wave length and thus a lower frequency
Compare swash the of constructive and destructive waves
The swash of constructive waves is stronger meaning they cause deposition
Compare the back wash of constructive and destructive waves
The backwash of destructive waves is stronger meaning they cause erosion
What is longshore drift?
The zigzag movement of sediment along the shore. The prevailing wind determines the directed of LSD, causing the swash to surge up at an oblique angle and the backwash goes back down at right angles
What are two types of physical weathering
1) freeze-thaw weathering
2) salt weathering
Describe the process of freeze thaw weathering
1) water trickles into cracks in a rock face
2) water freeze and expands by 10%, exerting pressure and widening the crack
3) ice melts and pressure is released
4) constant reputation of this cycle causes angular rock fragments to break away
Describe the process of salt weathering
1) salt crystals are left on rocks after salt water evaporates
2) they enter the pore spaces opening them up and creating holes in the rock
What are three types of chemical weathering?
1) carbonation
2) hydrolysis
3) oxidation
Describe the process of carbonation
1) carbon dioxide gas dissolved in rain to form weak carbonic acid
2) acid reacts with limestone
3) product carried away in solution
What is mass movement?
The movement of material downslope under the influence of gravity
What is rockfall?
When individual fragments of rock fall off a cliff (usually due to freeze thaw)
What is a landslide?
When rock falls in a linear fashion along fault lines
What is slumping?
The downward rotation of sections of a cliff often after heavy rainfall has made the soil saturated
What is mudflow?
When saturated soil or weak rock flows downslope
What is deposition?
When the sea loses energy and drops the sediment it has been carrying
What is weathering?
The breakdown of rocks in situ
What is erosion?
The wearing away and removing of material by a moving force
What is attrition?
Erosion caused by rocks bashing into each other, becoming smoother and breaking up into smaller pieces
What is abrasion/corrasion?
Erosion of cliffs by sediment flung by breaking waves
What is hydraulic action?
Erosion caused water compressing pockets of air in cliffs causing the crack to widen
What is solution?
Erosion caused by a chemical reaction that dissolves rocks
Give an example of an arch in the Dorset coastline
Durdle Door
Give an example of a cove in the Dorset coastline
Lulworth cove