coastal zone

Question 1

What is weathering?

Answer 1

the breakdown of rocks where they are.

Question 2

What is erosion?

Answer 2

When the rocks are broken down and carried away by something eg sea water.

Question 3

What is mechanical weathering?

Answer 3

the break down of rock without changing its chemical composition.

Question 4

Name one type of mechanical weathering?

Answer 4

Freeze-thaw weathering

Question 5

What is freeze-thaw weathering?

Answer 5

temp alternates above and below 0*C
water gets in cracks
water freezes , rock expands, putting pressure on rock,
water thaws, rock contracts releasing pressure
repeats which causes cracks to widen and break up.

Question 6

What is chemical weathering?

Answer 6

The breakdown of rock by changing its chemical composition.

Question 7

Name a type of chemical weathering?

Answer 7

Carbonation weathering which happens in warm and wet conditions.

Question 8

What is carbonation weathering?

Answer 8

Rainwater has carbon dioxide dissolved in it which makes it a weak carbonic acid.
Carbonic acid reacts with rock that contains calcium carbonate e.g carboniferous limestone, so rocks dissolve by rainwater.

Question 9

What is mass movement?

Answer 9

shifting of rock and loose material down a slope eg cliff.

Question 10

How does mass movement happen?

Answer 10

when the force of gravity acting on a slope is greater than the force supporting it

Question 11

When is mass movement likely to happen?

Answer 11

When the material is full of water as it acts like a lubricant.

Question 12

What does mass movement cause?

Answer 12

coasts to retreat rapidly.

Question 13

Name two types of mass movement?

Answer 13

slides ( material shifts in a straight line) and slumps( material shifts with a rotation.

Question 14

what are the four processes of erosion?

Answer 14

Hydraulic power -(waves crash against rock ,compress air which causes pressure on rocks repeats widens cracks and breaks off)
Abrasion -(eroded particles scrape/rub against rock removing small bits)
Attrition-(eroded particles in water smash into each other and break into smaller fragments)
Solution-( weak carbonic acid in seawater dissolves rock like chalk/limestone

Question 15

What are the waves called that carry out erosional processes?

Answer 15

Destructive waves.

Question 16

What is a destructive wave?

Answer 16

high in frequency, high and steep, more powerful backwash than swash( movement of water up the beach)
so material is removed from the coast.

Question 17

Erosion by waves cause what to cliffs?

Answer 17

wave cut platforms.

Question 18

Where does the wave erosion mostly happen?

Answer 18

The foot (bottom) of the cliff. first a wave-cut notch which is enlarged as the erosion continues. Rock above becomes unstable and collapses. Collapsed material washes away. the process repeat and the wave cut platform is left behind.

Question 19

Where do headlands and bays form?

Answer 19

Where there is alternating bands of resistant and less-resistant rock along a coast.

Question 20

Name one less-resistant rock?

Answer 20

clay. Its erodes quickly and washes away to cause a bay ( bays have a gentle slope).

Question 21

Name a resistant rock?

Answer 21

Chalk. erodes slowly and is left jutting out forming a headland ( headlands have steep sides) can have weakness like cracks.

Question 22

What can form in an eroded headland?

Answer 22

Caves, arches and stacks.

Question 23

How is a cave formed?

Answer 23

Waves crash into headlands and enlarge the cracks. Repeated erosion enlarges crack to form cave

Question 24

How does an arch form?

Answer 24

Erosion continues through cave until it breaks through the headland.Durdle door. Erosion continues until rock supporting arch collapses and leaves a stack. old Harry

Question 25

What is transportation?

Answer 25

The movement of material by a process called longshore drift.

Question 26

What is the prevailing wind? do waves follow these winds

Answer 26

The most common wind. yes waves follow.

Question 27

Do waves hit the coast at right angles?

Answer 27

No oblique angles ( anything that isnt a right angle.

Question 28

How does longshore drift happen?

Answer 28

Swash carries material up the beach in the same direction as waves. The backwash then carries material at right angle back towards the sea.

Question 29

What is traction?

Answer 29

Traction- large particles like boulders pushed along the seabed by force of water.

Question 30

what are the four processes of coastal transportation called?

Answer 30

Traction
suspension
saltation
solution

Question 31

What is suspension?

Answer 31

Small particles like silt and clay are carried along the water.

Question 32

What is saltation?

Answer 32

pebble size particles bounce along the seabed by force of water.

Question 33

What is solution?

Answer 33

soluble materials dissolve in the water and are carried along.

Question 34

What is deposition?

Answer 34

When the materials being carried are dropped on the coast.

Question 35

What happens if deposition is greater than erosion?

Answer 35

Coasts are built up.

Question 36

When is deposition increased?

Answer 36

lots of erosion elsewhere on the coast.
lots of transportation of material into the area.
low energy(slow) waves ( not strong enough to take alot of material away)

Question 37

What are constructive waves?

Answer 37

Waves that deposit more material than they erode.

Question 38

Info on constructive waves?

Answer 38

low frequency 6-8 waves per minute
low and long
powerful swash which carries material up the coast
backwash is weaker doesnt take alot of material back down.