Coastal Processes And Landforms.

Question 1

What are the two types of waves?

Answer 1

Constructive waves
Destructive waves

Question 2

What are the features of a constructive wave?

Answer 2

Have a weak backwash compared to swash.

They are gentle (they break at a rate of nine waves per minute)

They are long in relation to their hight

Add material to the coastline- deposition.

Question 3

What are the features of a destructive wave?

Answer 3

They form frequently (10 per minute)

Strong backwash compared to swash.

High in relation to their length.

Question 4

What are the four types of erosion?

Answer 4

CASH

Corrasion:
Bits of rock and sand in waves grind down surfaces and may cause undercutting.

Attrition:
Waves smash rocks and pebbles together.

Solution: acids contained in seawater dissolve rock (such as chalk or limestone) from the seabed or cliffs.

Hydraulic action:
Waves can physically wash away soft rocks. Air may become trapped in cracks and widen them.

Question 5

What is the coast?

Answer 5

Where the land meets the sea. Coasts are dynamic, and constantly change.

Question 6

How are waves formed?

Answer 6

Waves are caused by wind blowing over a stretch of water, called the fetch. The fetch is therefore the distance the wave has traveled.

The larger the fetch or wind speed, the larger the wave.

As a wave reaches shore, it slows. The lower section slows more than the upper section, causing it to topple.

Question 7

Learn the diagram of how waves form

Answer 7

Ok

Question 8

What is longshore drift?

Answer 8

When waves move material in one direction more than the other. This is due to prevailing winds hitting the beach at an angle.

The waves move diagonally across the beach, and then retreat downwards, creating a zigzag pattern and carrying sediment with them.

Question 9

What coastal landforms are caused by erosion?

Answer 9

Headlands
Cliffs and wave cut platforms
Caves, arches and stacks.

Question 10

What are headlands?

Answer 10

Stretches of coastline don’t erode evenly. Cliffs with harder rock resist erosion, and eventually stick out.

Question 11

What are cliffs?
Give an example of a cliff.

Answer 11

A vertical rock face along the coast.

The shape of a cliff is determined by: type of rock (which may be more or less resistant to erosion) or the way the layers of rock are angled.

E.g Cliffs of Moher- tall, dramatic cliffs.

Learn the cliff shape diagrams.

Question 12

What is a wave cut platform?
How does it form?

Answer 12

A narrow flat area often seen at the base of a cliff.

A notch is formed on the side of a cliff due to corrasion and hydraulic action, which undercuts the cliff and causes it to collapse.

Learn the diagram for the formation of a wave cut platform.

Question 13

How do caves arches and stacks form?
Give some examples.

Answer 13

A wave cut notch may enlarge into a cave. This cave may erode through the headland and form an arch. Over time this arch will get larger and larger due to being undermined by waves, until it can no longer support itself and the roof collapses, leaving behind a single pillar known as a stack.

Eg, green bridge of Wales- arch
Old man of hoy- stack.

Question 14

What coastal landforms are caused by deposition?

Answer 14

Beaches
Spits

Question 15

What is a beach?

Answer 15

Formed in the intertidal area, constructive waves push material like sand, shingle and pebbles on the coast. This material can build up and be blown inshore, creating a beach.

The cross section of a beach is called the beach profile.

On Sandy beaches, backwash removes material, creating a gently sloping beach.
On shingle beaches, the large particle size allows for percolation, reducing the energy of a waves backwash. This creates a steep beach.

Learn the beach profile diagram.

Question 16

What is a spit? How do they form and what conditions need to be present in order for them to form?

Answer 16

Depositional features made of sand that look like beaches and extend out from the mainland into the sea.

In order for them to form, the following conditions need to be met:

There is a constant supply of sand or other material from erosion further up the coast.
Longshore drift operating most of the time
The coastline has a sudden change in direction to leave a sheltered Bay Area.
The sea is quite shallow.

When the material reaches a break in the coastline, longshore drift makes the sand continue on, forming a spit. If they occur at an estuary, they may become established as new material builds up behind them. If the angle of the waves change, it may form a hooked spit.