Coasts

Question 1

What are the 2 landforms of coastal erosion?

Answer 1

Cliffs and wave cut platforms

Cliff profile features

Question 2

What are the 3 factors affecting the development of cliffs and wave cut platforms?

Answer 2

Rock type
Wave energy
Coastal morphology

Question 3

Explain how wave cut platforms form.

Answer 3

When destructive waves break at the foot of a cliff their energy is concentrated onto a small area of the rock face between high water mark and LWM.
Erosion undercuts the cliff forming a wave cut notch.
The overhanging cliff is subject to weathering and eventually collapses.
After successive collapses the cliff line will begin to retreat, forming a gently sloping wave cut platform at the base of the cliff.

Question 4

Which type of erosion is the most significant in forming wave cut notches?

Answer 4

Abrasion

Question 5

What angle are wave cut platforms at?

Answer 5

Less than 5 degrees

Question 6

Why do wave cut platforms not grow bigger than 500m?

Answer 6

As the platform grows the waves break further out to sea and their energy is dissipated before reaching the cliffs - forming a negative feedback loop

Question 7

How can wave-cut platforms become rough and jagged?

Answer 7

If the platform remains in the tidal zone it will be continually exposed to cycles of marine and sub-aerial processes, exploiting weaknesses in the rock surface.

Question 8

What features may form on wave cut platforms that remain in the tidal zone?

Answer 8

Rock pools and fissures

Question 9

Give an example of a wave cut platform in the UK.

Answer 9

Flamborough Head, North Yorkshire

Question 10

How long can wave-cut platforms take to form?

Answer 10

100s - 1000s of years

Question 11

What landforms form on coastlines of emergence?

Answer 11

Raised beaches

Wave cut platforms

Question 12

What are marine features that are left above the high tide level called?

Answer 12

Relict features

Question 13

Why may raised beaches appear as grassy terraces?

Answer 13

Once above the high tide line they are subject to vegetation succession

Question 14

What landforms form on coastlines of submergence?

Answer 14

Rias and fjords

Dalmatian coasts

Question 15

What are rias?

Answer 15

Coastal inlets

Question 16

How do rias form?

Answer 16

Sea level rises relative to the land, flooding river valleys

Question 17

How do fjords form?

Answer 17

Glaciers erode to create steep-sided U-shaped valleys.

Sea level rises relative to the land, flooding the glacial valleys.

Question 18

Why are fjords often shallower at the mouth than further inland?

Answer 18

Glaciers can overdeepen their valley

Question 19

How do Dalmatian coasts form?

Answer 19

Sea level rises relative to the land.

River systems which once ran parallel to the coast are flooded

Question 20

What are Dalmatian coasts?

Answer 20

A series of long islands that were once hills along valley sides.

Question 21

What is the key difference between Dalmatian coasts and rias?

Answer 21

The angle to the coastline at which they run

Question 22

What are the 2 different types of sea level change?

Answer 22

Isostatic

Eustatic

Question 23

What is isostatic sea level change?

Answer 23

Changes in sea level as a result of the changing level of the land.

Question 24

What is eustatic sea level change?

Answer 24

Changes in sea level as a result of the changing level of water in the oceans.

Question 25

On what scale does isostatic sea level change occur?

Answer 25

Local/regional

Question 26

On what scale does eustatic sea level change occur?

Answer 26

Global

Question 27

How quickly are sea levels currently rising?

Answer 27

3.2mm per year

Question 28

What is the main reason for current sea level rise?

Answer 28

Thermal expansion

Question 29

What are the 3 causes of isostatic change?

Answer 29

Tectonic activity
Glaciation
Post-glacial readjustment

Question 30

What are the 2 factors affecting the development of mudflats and saltmarshes?

Answer 30

Energy of coastlines

Tidal range

Question 31

What type of energy coastline do estuarine landforms form on?

Answer 31

Low energy coastlines

Question 32

What kind of succession is the formation of saltmarshes?

Answer 32

Halosere

Question 33

How do mudlfats form?

Answer 33

Saltwater flowing into an estuary at high tide brings large amounts of fine sediments.
This meets the slow river which is carrying fine silts and clays.
Flocculation occurs when the two flows meet, resulting in large clay particles sinking to the bed.
At low tide this mud is exposed in the intertidal area with water flowing in channels between the mudflats.

Question 34

How do mudflats develop into saltmarshes?

Answer 34

Low lying vegetation begins to grow on the mudflats.
This slows currents leading to further deposition.
Pioneer species colonise the area.
Gradual colonisation by other plants forms a dense mat of vegetation up to 15cm high.
Vegetation growth slows currents further, leading to more mud and silt accumulation.
The mudflats are submerged for an increasingly shorter period of time so become a saltmarsh.

Question 35

Give an example of a pioneer species on mudflats.

Answer 35

Spartina

Question 36

What is flocculation?

Answer 36

Where fine particles settle out of suspension

Question 37

Why are sand beaches gently sloped?

Answer 37

Sand grains are small and easily compacted so little water percolates through. The majority of water moving up the beach therefore also returns through backwash which smooths and flattens the beach.

Question 38

Why does shingle tend to be at the top of the beach?

Answer 38

It takes high energy storm waves to deposit the larger material.

Question 39

What are the 2 classifications of beaches?

Answer 39

Swash-aligned

Drift-aligned

Question 40

Sand dunes

Answer 40

Embryo -> Yellow -> Grey -> Woodland

MARRAM GRASS