Coasts Eq2

Question 1

What are constructive waves

Answer 1

Low height, long wavelength, strong swash (the forward movement of a wave up a beach), weak backwash (the backward movement of a wave down a beach), pushes sediment up creating a ridge

Question 2

What are destructive waves

Answer 2

High waves height, short wavelength, strong backwash, weak swash, so sediment is eroded and carried creating an offshore ridge

Question 3

What is hydraulic action

Answer 3

Sheer force of water crashing against the coastline causing material to be dislodged and carried away

Question 4

What is corrosion

Answer 4

Process of chemical erosion, occurs in limestone

Question 5

What is attrition

Answer 5

When material such as rocks and stones carried by waves hit and knock against each other, wearing them down

Question 6

What is abrasion

Answer 6

When rocks and other materials carried by the sea are picked up by strong winds and thrown against the coastline causing more material to be broken off and carried away by the sea

Question 7

Wave cut notches

Answer 7

Curved indentation 1-2 metres high extending along the base of a cliff, as a result of abrasion, hydraulic action, and sometimes corrosion between high and low tide marks

Question 8

Wave cut platforms

Answer 8

Flat rock surface exposed at low tide, extending out to sea from the base of a cliff, occurs when a wave cut notch forms and the rock above collapses

Question 9

What is cave-arch-stack-stump

Answer 9

Cracks are formed in rock due to abrasion, when waves force themselves into the cracks, caves are formed,when this continues to the other side, arches are formed, when the material above an arch collapsed, stacks are formed, and then when this erodes, stumps are formed

Question 10

What is a cliff

Answer 10

Vertical, or near vertical, or sloping wall of rock or sediment that borders the sea, angle of slope differs due to rock structure and geology, though the processes that act on them are the same

Question 11

What is traction

Answer 11

Large material rolling or sliding along the seabed

Question 12

What is saltation

Answer 12

Sand and small sediment bounces along the seabed

Question 13

What is suspension

Answer 13

Lighter, finer sediment is carried within the water

Question 14

What is solution

Answer 14

Ions dissolved in the water

Question 15

What is longshore drift

Answer 15

Waves approach the coast at an angle due to prevailing wind, the swash pushes the sediment up the beach at an angle, the backwash pulls the sediment down, causing it to move in a zigzag pattern, this results in the net movement of sediment along the beach

Question 16

What is wave refraction

Answer 16

When waves approach shallow water and slow down due to friction, waves in the bays continue to move at the same rate, which concentrates energy to the headlands, increasing erosion and spreads out energy in the bay, increasing deposition

Question 17

What is a spit

Answer 17

When a beach extends along a curve in the coastline, the longshore drift current loses energy, causing deposition

Question 18

What is a swash aligned shoreline

Answer 18

When waves approach the beach parallel to the shoreline, so longshore drift is limited

Question 19

What is a drift aligned shoreline

Answer 19

When waves approach the beach at an angle, so there is consistent longshore drift

Question 20

What is a cuspate foreland

Answer 20

Triangular shaped feature extending out from shoreline, caused by opposing longshore drift directions

Question 21

What is a bar

Answer 21

A bridge connecting two areas of land, with a shallow lagoon behind it

Question 22

What is a tombolo

Answer 22

A bar that attaches to an offshore island, caused by wave refraction around the island which leads to deposition

Question 23

What is a bayhead beach

Answer 23

Swash aligned beach where waves move sediment into a bay

Question 24

What is gravity settling

Answer 24

Energy of waves is not great enough to transport sediment, so larger material settles first, followed by smaller material

Question 25

What is flocculation

Answer 25

Very fine particles like clay ‘clump’ together due to electrostatic attraction and then, when they have formed larger particles, they sink

Question 26

What is an example of a sediment cell

Answer 26

Flamborough head to the wash

Question 27

2 examples of mechanical weathering

Answer 27

Freeze thaw (water expands when it freezes and exerts mechanical force on the rocks surrounding it), exfoliation (sometimes referred to onion skin weathering, when sheets or layers of rock split off due to differential thermal expansion)

Question 28

2 examples of biological weathering

Answer 28

Burrowing - when worms and vertebrate animals burrow and bring rocks to the surface allowing chemical weathering to occur at a greater depth
Root action - causes mechanical and chemical weathering of rock due to wedging action of plant roots that grow along joints and bedding planes

Question 29

1 examples of chemical weathering

Answer 29

Carbonation - occurs in limestone coasts, sea water reacts with limestone and forms acid, which washes away

Question 30

What is rock fall

Answer 30

Fragments of rock break away from the cliff face due to weathering
Occurs where there is more brittle, resistant rock, usually results in steep cliff profiles,

Question 31

What is a landslide

Answer 31

Blocks of rock slide down the hill
Occurs frequently when strata are dipping towards the coast, rock with joints are more vulnerable, results in a sloping cliff profile

Question 32

What is a mudslide

Answer 32

Saturated soil flows down a slope
Occurs in unconsolidated material that is saturated with water, results in sloping cliff profiles

Question 33

What is slumping

Answer 33

Saturated soil slumps along a curved surface
Occurs in unconsolidated sediment, especially when wet, results in step-like cliff profile

Question 34

What is meant by dynamic equilibrium

Answer 34

Coastal systems are always trying to reach a balance point between the amount of energy in an area and the amount of sediment
E.g in winter, storms create destructive waves which forms an offshore ridge, in summer the offshore bar creates a barrier, forming constructive waves which bring sediment back up the beach