Marine Processes

Question 1

Examples of specific erosion changes in UK(4+)

Answer 1

In 2014 a particularly powerful storm hit Dawlish
Destroyed part of the sea wall + section of rail track cutting the rail connection between Devon and Cornwall for two months
Storm of February 2014 altered the Devon coastline
Sand dunes at Dawlish Warren (spit) were severely eroded

Question 2

Erosion all processes (6)

Answer 2

Hydraulic action
Abrasion
Attrition
Wave quarrying
Solution
Corrasion

Question 3

Hydraulic action what (4+)

Answer 3

Waves break against a rock face and go into cracks
Air inside the cracks is highly compressed = enormous pressure
As the water pulls back = explosive effect of the air under pressure being released
Overall effect over time = weakens the cliff face

Question 4

What is wave quarrying (2+)

Answer 4

Impact on rocks of the sheer force of water itself
Exerts pressure upon a rock surface = weakens it + dislodges pieces

Question 5

Corrasion (3+)

Answer 5

Sand and pebbles picked up by sea wears away rock faces
When wave breaks at the foot of the cliff the transported material is hurled at the base of the cliff
Chips away at the rock

Question 6

What is abrasion (3+)

Answer 6

As waves wash over rocky surfaces sediment is dragged to and fro
Over time this smooths and erodes the rock
‘sandpapering effect’

Question 7

Solution (2)

Answer 7

Weak acids in seawater dissolve alkaline rock - chalk or limestone
The dissolved minerals can then be removed in solution

Question 8

Attrition (2+)

Answer 8

Angular rock fragments are smoothed and reducing in size forming pebbles, shingle and sand
Due to friction as particles are rolled over each other by the action of waves and currents

Question 9

What effects rate of erosion (4)

Answer 9

Geology
Wave energy
Human activity
Beach presence or absence

Question 10

How does beach presence or absence effect erosion (2)

Answer 10

No beach = more vulnerable
Beach = absorbs wave energy

Question 11

How does human activity effect erosion rates (2+)

Answer 11

beach material is removed from some coastlines = erosion
Coastal protection = sea walls or groynes = may reduce the rate of erosion but speed up further down beach

Question 12

How do waves effect erosion (2+(

Answer 12

Steeper, high energy waves will erode = destructive waves
Less powerful waves = deposition = constructive waves

Question 13

What is lithology (3)

Answer 13

Type of rock
Granite = very resistant to erosion
Clay = very vulnerable to erosion

Question 14

Example of lithology effects (2+)

Answer 14

In the past century the granite at Land’s End has been eroded by just 10cm
Whilst boulder clay of the Holderness Coast has been eroded by 120m

Question 15

Types of coastlines (2)

Answer 15

Concordant
Discordant

Question 16

What is discordant coastline (2(

Answer 16

Alternating bands of hard and soft rock that are perpendicular to coast
Headlands and bays

Question 17

What is a concordant coastline (3+)

Answer 17

Alternating bands of hard and soft rock that are parallel to the coastline
Soft rock erodes = hollowed out = cove
Straight lines of cliffs form

Question 18

What is the dip on a coastline (3)

Answer 18

Where cliffs have horizontal strata which may dip
Rocks dip inland = steeper cliffs form
Rocks dip Seward = cliffs tend to be more gently sloping