Coasts EQ2

Question 1

What 4 factors does wave size depend on?

Answer 1

strength of wind
duration wind has blown for
water depth
fetch

Question 2

True or false: when the water column depth is less than the wavelength, the wave will start to break

Answer 2

TRUE

Question 3

Describe constructive waves

Answer 3

swash more powerful than backwash
low surging waves
long wavelength
beach gain

Question 4

Describe destructive waves

Answer 4

stronger backwash than swash
high plunging waves
short wavelength
beach loss

Question 5

What is meant by beach morphology?

Answer 5

shape of a beach

beach profile

Question 6

How does beach morphology change in different timescales?

Answer 6

over a day - storms pass and destructive waves change to constructive
between summer and winter
changes to climate

Question 7

List 4 beach landforms that change constantly

Answer 7

storm beach height
beam ridges
runnels and channels
offshore ridges/bars

Question 8

State 3 differences between summer and winter beaches

Answer 8

summer: steeper profiles, smaller towards shore (waves have less energy), berms of shingle, constructive waves
winter: berms eroded by high energy swash, destructive waves, offshore bars (created by strong backwash)

Question 9

List the 4 erosion processes and describe them

Answer 9

hydraulic action - air trapped in joints, air compressed when wave breaks , expanding cracks

abrasion (corrasion) - waves carrying pebbles and sand break and material is hurled up cliff

attrition - sediment is chipped after collisions in waves

corrosion (solution) - carbonate rocks vulnerable to solution by salt water

Question 10

What are erosion types influenced by?

Answer 10

wave type, size and lithology

Question 11

List 5 erosional landforms

Answer 11

headlands and bays
wave cut notch
shoreline platform
cave, arch,stack and stump 
cliff

Question 12

On what kind of coasts do headlands and bays form?

Answer 12

discordant (hard and soft perpendicular)

Question 13

How are wave cut notches created?

Answer 13

waves break against foot of cliff so erosion is concentrated

Question 14

How are shoreline platforms/ wave cut platforms created?

Answer 14

notch retreats inland as erosion continues causing cliff to retreat leaving platform

Question 15

How do wave cut platforms reduce erosion?

Answer 15

width means waves break earlier

Question 16

True or false? vertical or horizontal strata produces gentler cliffs?

Answer 16

FALSE - steeper

Question 17

Describe the 4 types of transportation in order of particle size

Answer 17

traction - sediment rolled along
saltation - sediment bounces
suspension - sediment carried in water column
solution - dissolved material carried

Question 18

What is sediment transportation influenced by?

Answer 18

angle of wave attack, currents, longshore drift, tides

Question 19

In what two ways can deposition occur?

Answer 19

gravity settling occurs when energy of transporting water becomes too low to move sediment

flocculation (process for small particles) clay particles clump together through electrical or chemical attraction and become large enough to sink

Question 20

List 5 depositional landforms

Answer 20

spits
beaches
bars
tombolo's
cuspate foreland

Question 21

What is the difference between swash aligned and drift aligned beaches?

Answer 21

swash aligned - sediment moves up and down beach as wave breaks parallel with coast
drift aligned - sediment transferred by longshore dirftas wave breaks at an angle to coast

Question 22

On what kind of beach (swash or drift aligned) to spits form on?

Answer 22

drift

Question 23

How do spits form?

Answer 23

sediment moved along by LSD but a sudden coastline direction change causing sediment to build up along estuary mouth

the deposition occurs because the LSD current spreads out and loses energy

Question 24

How are bars formed?

Answer 24

beach or spit extends across bay

Question 25

How are offshore bars formed?

Answer 25

destructive waves erode sand from beach and deposit it they are ridges of sediment created by offshore waves

Question 26

What are tombolo's and how are they formed?

Answer 26

beach that has formed between a small island and mainland | form as a result of wave refraction around offshore island creating area of calm water = deposition

Question 27

How do double spits form?

Answer 27

different wave refractions e.g Isle of Purbeck

Question 28

What is a cuspate foreland and how is it formed?

Answer 28

triangular shaped foreland | occurs when coast is exposed to LSD from opposite directions

Question 29

What are the three components of the sediment cell concept?

Answer 29

sources, transfers, sinks

Question 30

What is meant by sources in the sediment cell concept? b) transfers c) sinks

Answer 30

places where sediment is generated b) places where sediment is moving alongshore (via LSD or currents) c) depositional land forms

Question 31

Give an example of two sources

Answer 31

erosion of cliffs, subaerial processes

Question 32

Give an example of two transfers

Answer 32

LSD, wave transport through swash and backwash

Question 33

Give an example of two sinks

Answer 33

near shore and foreshore depositional landforms

Question 34

What is the amount of sediment available within a cell called?

Answer 34

sediment budget

Question 35

In what 3 states can sediment cell be in

Answer 35

equilibrium positive feedback negative feedback

Question 36

What is meant by sediment cell being in equilibrium? +ve feedback -ve feedback

Answer 36

as much being deposited as taken when the changed produces an effect that operates to increase the original change when the change produced creates effects that operate to reduce or work against the original change

Question 37

Give an example of positive feedback

Answer 37

damage to sand dunes during storm prevents grass growing = eroision

Question 38

Give an example of negative feedback

Answer 38

wave erosion causes rocks to fall = protects base from eroision

Question 39

How many sediment cells (divisions along coast line) are in the UK?

Answer 39

11 | each with their own SMP

Question 40

What is meant by subaerial processes?

Answer 40

weathering and mass movement

Question 41

What are the three types of weathering

Answer 41

mechanical chemical biological

Question 42

What is meant by lithology?

Answer 42

rock types

Question 43

Describe 2 types of mechanical weathering

Answer 43

freeze thaw- water enters crack and expands as it freezes putting pressure on rock and causing it to eventually break wetting and drying- rocks rich in clay expand when they get wet and contract as they dry causing them to crack

Question 44

Describe 2 types of chemical weathering

Answer 44

carbonation- rainwater absorbs C02 from air to form a weak carbonic acid which react with calcium carbonate in rock making it dissolvable oxidation- addition of oxygen to minerals increases volume contributing to breakdown

Question 45

Describe 2 types of biological weathering

Answer 45

plant roots- roots growing in cracks force rocks apart animals- dig burrows causing them to break

Question 46

Describe the 3 types of mass movement and where they occur

Answer 46

blockfall- large rocks fall away from the cliff as a single piece due to the jointing of the rock occur on strong, steep, joined cliffs roational slumping- material slowly rotates downslope often when in saturated condition occur on cliffs where softer materials overlie more resistant rock landslides- rocks that are jointed or have bedding planes roughly parallel to the slope or cliff surface are susceptible occur often when there is an increase in the amount of water that reduces the friction (causing sliding)

Question 47

What kind of landform is created as a result of block fall?

Answer 47

Talus scree slopes scree at the bottom

Question 48

What kind of landform is created as a result of rotational slumping?

Answer 48

rotational scars | and terraced cliffs

Question 49

What kind of landform is created as a result of landslides?

Answer 49

terraced cliffs