Coast

Question 1

What is “marine erosion”?

Answer 1

Wearing away of cliffs by waves

Question 2

Corrasion/Abrasion

Answer 2

Large waves hurl beach material

Question 3

Corrosion/solution

Answer 3

Salts + acids slowly dissolve

Question 4

Attrition

Answer 4

Waves

stones collide + disintegrate

Question 5

Hydraulic Action

Answer 5

Force of waves compresses air in the cliffs

Question 6

Constructive waves

Answer 6

Low height
Gentle beach gradient
Swash > backswash

–> Deposit material + build up beaches

Question 7

Destructive waves

Answer 7

High height
Steep beach gradient
Backswash > Swash

–> Erosion (beach material is pulled down the beach)

Question 8

Longshore drift processes

Answer 8

1. Oblique onshore winds drive wave crest at an angle to shore
2. Swash carries materials up beach at an oblique angle
3. Backswash brings materials straight down
4. Gradually move materials along beach in zig-zag motion.

Question 9

Explain why some coastlines have headlands and bays

Answer 9

Alternate bands of hard and soft rock along coasts

hard rock resists erosion
forming headlands

soft rock easily eroded
forming bays

differential erosion (?)

Question 10

Explain how different erosional processes shape cliffs + wave-cut platform

Answer 10

Hydraulic action/ corrasion/ corrosion/ where is attrition (explain)

undercutting

Rock above collapse

as cliff cannot take weight of overhanging section

Wave-cut platform where cliff once stood

Question 11

Conditions needed for formation of sand dunes

Answer 11

on a sand spit
onshore winds
supply of sand
obstruction for sand to build up around
marram grass to hold them together

Question 12

How a sand spits is formed

Answer 12

MORE

Content Guide:
Answers are likely to refer to;
Prevailing wind,
Longshore drift,
Deposition,
Change of direction of coastline etc.

Question 13

How a natural arch is formed

Answer 13

erosion ( hydraulic action/corrosion);
description of process
enlarges joints on resistant rock
formation of cave
cave breaks through headland to form arch

Question 14

Explain how erosion by the sea may cause problems for people living in coastal area

Answer 14

Ideas such as:
• danger to properties on cliff top;
• people may need to evacuate;
• loss of farmland/loss of gardens;
• reduction in food production;
• roads may be damaged;
• collapse of cliffs may make beaches dangerous/rock falls can kill people;
• less tourists come;
• cost of protection measures;
• can’t get insurance for properties/unable to sell properties; etc.