Coastal Landscapes and Change

Question 1

What are sources?

Answer 1

Where sediment originates from

Question 2

What are through flows?

Answer 2

the movement of sediment along the shore through longshore drift

Question 3

what are sinks?

Answer 3

locations where deposition of sediment dominates

Question 4

what does positive feedback loop do?

Answer 4

exaggerates the change making a system more unstable and taking it away from dynamic equilibrium.

Question 5

what does a negative feedback loop do?

Answer 5

lessens any change which has occured within the system.

Question 6

what is the littoral zone?

Answer 6

the area of coast where land is subject to wave action.

Question 7

what is backshore?

Answer 7

area above high tide level and only affected by exceptionally high tides.

Question 8

what is foreshore?

Answer 8

this is land where most wave processes occur

Question 9

what is offshore?

Answer 9

the open sea

Question 10

what is Valentines classification?

Answer 10

describes the range of classification that can occur.

Question 11

what is corrasion?

Answer 11

Sand and pebbles are hurled at the cliff. the power and speed of waves will affect the rate of erosion to the cliff

Question 12

what is abrasion?

Answer 12

where sediment is moved along the shoreline causing it to be worn down over time. rubbing rather than throwing it at the cliff.

Question 13

what is attrition?

Answer 13

wave action cause rocks and pebbles to be hit against each other, wearing each other down and so becoming round and eventually smaller.

Question 14

what is hydraulic action?

Answer 14

as a wave crashes into the cliff face, air is forced into the cracks within the rock. the high pressure causes the cracks to force apart and widen when the wave retreats and the air expands. over time this causes the rock to fracture.

Question 15

what is corrosion?

Answer 15

the acidic seawater can cause alkaline rock such as limestone to be eroded and is very similar to carbonation weathering.

Question 16

what is wave quarrying?

Answer 16

this is when breaking waves that hit the cliff face exert a pressure. it is very similar to hydraulic action but acts with significantly more pressure which can directly pull rocks away from the cliff face.

Question 17

what are the three vulnerabilities of a rock that affect its impact from erosion?

Answer 17

-whether it is clastic or crystalline
-the amount of cracks, fractures and fissures
-the lithology of the rock

Question 18

what is a wave cut notch and platform?

Answer 18

marine erosion attacks the base of a cliff, creating a notch of eroded material. as the notch becomes deeper (sub-aerial weathering weakens the cliff from the top) the cliff face becomes unstable and falls under its own weight through mass movement. this leaves behind a platform of the unaffected cliff base beneath the wave-cut notch.

Question 19

what is a Blowhole?

Answer 19

a blowhole is a combination of two features: a pot hole on top of a cliff, created by chemical weathering, and a cave formed by marine erosion. as the cave erodes deeper into the cliff face and the pothole deepens, they may meet creating a channel for incoming waves to travel into.

Question 20

what is traction?

Answer 20

large, heavy sediment rolls along the sea bed, being pushed by currents.

Question 21

what is saltation?

Answer 21

smaller sediment bounces along the sea bed, being pushed by currents.

Question 22

what is suspension?

Answer 22

small sediment is carried within the water column

Question 23

what is solution?

Answer 23

dissolved material is carried within the water

Question 24

what does the term swash-aligned mean?

Answer 24

wave crests approach parallel to coast so there is limited longshore drift. sediment doesn’t travel up the beach farw

Question 25

what does the term drift-aligned mean?

Answer 25

waves approach at a significant angle, so longshore drift causes the sediment to travel far up the beach

Question 26

what does the term gravity settling mean?

Answer 26

the waves energy becomes very low and so heavy rocks and boulders are deposited followed by the next heaviest sediment.

Question 27

what does the term flocculation mean?

Answer 27

clay particles clump together due to chemical attraction and then sink due to their high density.

Question 28

what is a bar?

Answer 28

a spit which over time links up two sections of coast

Question 29

what are cuspate forelands?

Answer 29

only occurs with triangular headlands. longshore drift along each of side of the headland will create beaches, which where they meet, will form cuspate foreland.

Question 30

what are offshore bars?

Answer 30

a region offshore where sand is deposited, as the waves don't have enough energy to carry the sediment to shore. they can be formed as the wave breaks early, scouring the seabed and instantly depositing its sediment as a loose-sediment offshore bar.

Question 31

what does the term freeze-thaw mean?

Answer 31

water enters cracks in rocks and then the water freezes overnight during the winter. as it freezes, water expands which increases the pressure acting on the rock causing cracks to develop.

Question 32

what is salt crystallisation?

Answer 32

as seawater evaporates, salt is left behind. salt crystals will grow over time, exerting pressure on the rock, which forces the cracks to widen.

Question 33

what affects the type of mass movement?

Answer 33

-angle of the cliff -lithology and geology of the rock -vegetation cover on the surface

Question 34

what is soil creep?

Answer 34

the slowest but continuous form of mass movement of soil particles downhill.

Question 35

what is solifluction?

Answer 35

as the top layers thaws during summer (but the lower layers still stay frozen due to permafrost) the surface layers flows over the frozen layers

Question 36

what are mudflows?

Answer 36

an increase in the water content of soil can reduce friction, leading to earth and mud flow over underlying bedrock?

Question 37

what are concordant coastlines?

Answer 37

when the rock strata runs parallel to the coast

Question 38

what is a discordant coast?

Answer 38

when the rock strata runs perpendicular to the sea

Question 39

what are xerophytes?

Answer 39

plants that are tolerant of dry conditions

Question 40

what are halophytes?

Answer 40

plants that are tolerant of salty conditions

Question 41

what is isostatic change?

Answer 41

it is the local changes in sea level resulting from the land rising or falling relative to the sea.

Question 42

what is eustatic change?

Answer 42

global changes in sea level resulting from an actual increase or decrease in the volume of water in the ocean

Question 43

when would a storm surge occur?

Answer 43

when there is a short term change in sea level which may be due to low pressure during a depression or tropical cyclone