Landforms of coastal erosion

Question 1

Sea cliffs and wave cut platforms

Answer 1

1. when high and steep waves break at the foot of cliff they concentrate their erosional capabilities to a small area of the rock face
2. this eventually leads to the cliff being undercut forming a feature known as a wave cut notch
3. continued activity at this point increases the stress on the cliff and in time it collapses
4. The cliff begins to retreat and leaves a gently-sloping wave cut platform
5. the wave cut platform continues to grow and as it does the waves break further out to sea and have to travel across more platform before reaching the cliffs
6. this leads to greater dissipation of wave energy, reducing erosion

Question 2

describe a headland?

Answer 2

sections of bays which protrude out into the sea

Question 3

how do headland and bays form?

Answer 3

• headlands and bays are commonly formed when rocks of different strengths are exposed at a coastline. tougher more resistant rocks form headlands weaker rocks are eroded to form bays
• once formed headlands and bays interfere with oncoming waves, they make waves refract.
• wave refraction focuses wave energy on the headlands. the waves energy is spead out and reduced in the bays which results in deposition of sand and shingle to form beaches
• explain wave refraction

Question 4

what is wave refraction?

Answer 4

shallow water present around headland
increases friction
waves break at headland
energy is dissipated into bays

Question 5

what is a concordant coastline?

Answer 5

exist where rock structure is parallel to the coast

straight coastal plans resulting in a steep cliff face

Question 6

what is a discordant coastline?

Answer 6

alternating bands of less resistant and more resistant rock

Question 7

what are beaches?

Answer 7

represent the accumulation of material deposited between low spring tides and the highest point reached by storm waves - mainly constructed from sand and shingle

Question 8

how are berms formed?

Answer 8

formed by the swash during high tide and mark the limit of high tides.
they are the ridges at the back of the beach

Question 9

what are runnels?

Answer 9

found lower down beach

depressions in the sand between ridges left as the tide goes out.

Question 10

what are used to measure the beach profile?

Answer 10

ranging poles are used to measure the change in angle with a tape measure

Question 11

why is systematic sampling not used when measuring a beach profile?

Answer 11

it would miss changed in slope and finer detail

Question 12

what other data could you collect when measuring beach profile?

Answer 12

wind speed
wave and wind direction
direction of LSD

Question 13

what are the favorable conditions for the growth of spits and bars?

Answer 13

Bend or change in the direction of coastline
plentiful load
active LSD
environments favoring constructive waves

Question 14

what are the factors for reducing or stopping the growth of spits and bars?

Answer 14

reduction in the supply of sand and shingle
deeper water
strong river or tidal currents
more exposure to storm waves

Question 15

what are tombolos?

Answer 15

tombolos develop where a spit joins an island to the mainland. deposition occurs when waves lose energy

Question 16

when do bars occurs?

Answer 16

occur when there is a change in the coastal direction but no river estuary to break the sequence of sedimentation along the spit

Question 17

what is a barrier beach?

Answer 17

elongated bank of sand or shingle lying parallel to the coastline and not submerged by incoming waves

Question 18

what are offshore bars?

Answer 18

submerged or partly exposed ridges of sand and coarse sediment created by waves offshore from the coast

Question 19

what is aeolian depostition

Answer 19

an important process where the wind transports sediement. wind plays an important role in shaping many coastlines

Question 20

what is surface creep

Answer 20

wind rolls or slides sands grains along the surface