3.3 - Coastal geomorphology processes

Question 1

Define subaerial

Answer 1

Process at base of atmosphere which breaks down the coastline and weaken the underlying rock so a sudden movement of erosion can happen easily

Question 2

What is a marine process?

Answer 2

Operate upon a coastline and are connected with the sea (LSD, tides)

Question 3

Define LSD

Answer 3

Long short drift - prevailing winds at an angle to the coastline and swash transports sediment up the beach then backwash transports it towards sea at a right angle.
/I/I/I/I/I/I/I/I/I/I

Question 4

What is an offshore current?

Answer 4

E.g. rip current - move material to sea at a right angle. Sediment is deposited t form a sand bank or reshape depositional landforms

Question 5

Describe upwelling

Answer 5

Movement of cooler water from deep ocean due to surface winds pushing water away.

Question 6

What is a longshore current

Answer 6

Approach coast at an angle and generate a current running parallel to the shore. Transports sediment and water

Question 7

3 causes of a current

Answer 7

Wind, water temperature, salinity

Question 8

Define current

Answer 8

Large movement of water in one direction

Question 9

What is a rip current

Answer 9

Formed when a series of plunging waves cause a temporary build up at the top of a beach. Met will resistance from breaking waves. Backwash is forced below surface.

Question 10

Define bore

Answer 10

Wall of water that travels upstream for a considerable distance

Question 11

What is solution (transportation)

Answer 11

Dissolved material that is not visibly moving

Question 12

What is suspension

Answer 12

Small particles oved by light currents

Question 13

What is saltation

Answer 13

Pebbles bounce of sea bed

Question 14

What is traction

Answer 14

Rocks are dragged/rolled on sea bed

Question 15

4 reasons why energy flow declines and description

Answer 15

Energy source changes - weaken currents/prevailing winds

Discontinuity in flow - turbulence between opposite currents (end of spit)

Increased friction - more energy needed to big rocks deposited

Increased load - energy of system isn’t sufficient (sudden river discharge or landslip)

Question 16

What is the different between corrasion and abrasion

Answer 16

Corrasion - throw at cliff

Abrasion - drag along floor (sand paper)

Question 17

How does the wave steepness impact the rate of erosion?

Answer 17

Wave steepness - high energy = longer fetch = high and steep

Question 18

What are aeolian processes

Answer 18

Entrainment, transport and deposition of sediment by wind

Question 19

3 types of weathering

Answer 19

Biological, chemical, physical/mechanical

Question 20

What is biological weathering?

Answer 20

Action of vegetation and organisms. E.g. seaweed and plant roots

Question 21

2 examples and processes of mechanical weathering

Answer 21

Freeze thaw = +- 0oc. Water enters crack, freeze and expand up to 10%, exert pressure and crack widens (pressure relief)

Salt crystallisation - sea water enters crack, freeze and expand, evaporate and salt left behind, repeat

Question 22

Name the 5 types of chemical weathering

Answer 22

Oxidation

Hydration

Hydrolysis
Carbonation

Acid rain

Question 23

Define mass movement

Answer 23

Downslope movement of material due to gravity

Question 24

Define rockfall

Answer 24

Blocks dislodged by weathering fall

Question 25

Define landslide

Answer 25

Block of rock rapidly move along seaward dipping plane

Question 26

Define rotational slump

Answer 26

Sections of cliff give way on concave surface and rock/soil s unconsolidated

Question 27

Define mudflow

Answer 27

Storm/intense rainfall - soil lying over impermeable bedrock

Question 28

Define creep

Answer 28

Slow downslope movement of individual soil particles

Question 29

Define solifluction

Answer 29

Slow downslope of waterlogged regrowth. End of ice age (thaw)

Question 30

What influences mass movement (4)

Answer 30

Angle of slope
Rock type/structure
Vegetation cover
How wet ground is

Question 31

How does the breaking point of a wave impact the rate of erosion?

Answer 31

Cliff = release most energy   
Beach = energy dissipated

Question 32

How does the sea depth impact the rate of erosion?

Answer 32

Sea depth, length and fetch - steep = high wave = more energy

Question 33

How does the material supply impact the rate of erosion?

Answer 33

Beach absorbs energy

Question 34

How does the morphology impact the rate of erosion?

Answer 34

High energy wave = wide, flat beach

Question 35

How does the low energy waves impact the rate of erosion?

Answer 35

Narrow, steep beach

Question 36

How does the rock resistance impact the rate of erosion?

Answer 36

Joints, horizontal or vertical cliff

Question 37

What is oxidation?

Answer 37

Oxidation - Hydroxide forms and makes Fe rich rocks go brown

Question 38

What is hydration?

Answer 38

Hydration - Water makes rock expand then disintegrate by expanding to make faults/joints

Question 39

What is hydrolysis?

Answer 39

Hydrolysis - mildly acidic water reacts with minerals to form clay

Question 40

What is carbonation?

Answer 40

Carbonation - CO2 + H2O -> weak carbonic acid

H2CO3 + CaCO3 -> Ca(HCO₃)₂ (calcium bicarbonate which dissolves easily in water)

Question 41

What is acid rain?

Answer 41

Acid rain - sulphuric gasses