Coasts

Question 1

3.zones of a coast

Answer 1

Backshore- between the HWM and landward limit of marine activity.
foreshore- between HWM and LWM most important area for marine activity
Inshore - between LWM and where the waves stop having an impact
Offshore-beyond point

Question 2

2.Sediment cells definition

Answer 2

Stretch of coastline with movement of sediment sand and shingle generally viewed as a closed system (no sediment is transferred from one cell to another)

Question 3

6.Factors affecting the size of a wave

Answer 3

-wind speed
-duration wind blows for
-distance over which it blows

Question 4

6.5Constructive vs destructive waves

Answer 4

C
-long wavelength
-spill forwards
-strong swash
-weak backwash
-Low frequaenxy
D
-Short wavelength
-steep waves plunge over
-weak swash
-strong backwash
-high frequency

Question 5

4.How is wind created

Answer 5

Low pressure hot air rises (wet air)then cools into high pressure air then falls (dry air) then goes in a circuit as the earth is spinning this causes wind to change direction.

Question 6

16. Wave marine processes (Erosion types)

Answer 6

Abrasion
-material carried by waves hit cliff (sandpaper)
Hydraulic action
-compression of air and water in cracks forces cliff apart
Attrition
-material in water hit eachother (smaller and rounded)
Pounding
-force of wave hitting cliff
Solution
- chemical reaction dissolving material

Question 7

17.Transportation types

Answer 7

Suspension
-held up
Solution
-dissolved material
Sattation
-dumpin or hopping movement of sediment
Traction
-rolling along sea bed

Question 8

20.Longshore drift

Answer 8

Sediment can be moved by LSD
-when waves approach coastline at angle due to dominant winds
-when waves have broken swash carried sediment diagonally up beach the. Backwash moves back down TJE beach

Question 9

12. How landforms developed - weathering (physical) FESP

Answer 9

Freeze thaw
-water enters cracks then freezes and expands causing pressure so rock splits and breaks off
Exfoliation
-rocks expand when heated and construct wjen cooled outer layers of rock break off
Slat crystallisation
-salt solution deep into pores and cause crystals then rock disintegrates
Pressure release
-when overlaying rocks are removed by erosin TJE underlaying rock expands and fractures

Question 10

13. How landforms are developed -weathering (Chemical)COSHH

Answer 10

Oxidisation
-some mineral react with oxygen in air or water,acidic conditions so soluble and OG structure destroyed.
Carbonisation
-rainwater mixes is a weak co2 this reacts with calcium carbonate to produce bi carbonate which is soluble.
Solution-some minerals are soluble in water as they dissolve weaken structure of a rock.
Hydrolysis
-between rock minerals and water silicates combine with water producing secondary materials eg. Clay
Hydration
- water is added to rocks to created bigger volumes therefore surface flakes

Question 11

14. How costal landform develop - weathering (Biological)

Answer 11

Organic acids
-decomposition of animal and plant litter causes soil wayer to become more acidic and react with rock molecules.
Tree roots
-grow into cracks and joint in rocks and exert out pressure similar to freeze thaw

Question 12

8.Tides

Answer 12

The moon pulls the water towards it creating a high tide. Between blushes on opposite sides of earth there is low tide. When sun moon and earth are aligned is the highest tide called spring tide.

Question 13

10.Geology

Answer 13

Lithology- refers to the physical and chemical composition of rocks. Eg, chalk- weak Lithology as it has weak bonds between particles therefore less resistant to erosion,weathering and mass movements.
Structure- properties of rocks- jointing(crack,but in movement)bedding planes (separate layers) and faulting (cracks and movement across rock) which effec permeability of rocks
Porousrock
- pores can absorb and store water, allows water and air to pass through eg chalk, primary permeability.

Question 14

19.Concordant and discordant

Answer 14

Concordant is parallel to coast with same type of rock along coats.lil worth cove
Discordant - alternates if hard and soft rock more bays and headlands.swan age bay

Question 15

22.Geos and blow holes

Answer 15

Geos
-narrow steep sided Inlet
-weak points eroded then tunnel like cave - Pembrokeshire wales
Blow holes
-large waves force spray out anblowhole - New Zealand pancake rocks

Question 16

21.Formation of wave cut platform i

Answer 16

Destructive waves attack base of cliff causing undercut between HWM AND LWM mainly as a result of abrasion hydraulic

Question 17

24.formation of spit

Answer 17

Long narrow beaches of sand or shingle attached to land.Prevailing wind pushes sediment along coastline causing long shore drift, depositing sand or shingle into open water.
When original shape of coast changes LSD carries on causing a tip by secondary wind direction causing refracted waves and reconstructed laterals.
Salt marsh can be formed behind due to the meeting of sea to river )low energy) the river current flows between spit to make a bar
Mudeford soit

Question 18

18.Features of deposition

Answer 18

Beach
Spit
Bar
Tombolo

Question 19

25.Formation of bar

Answer 19

Created when a gap in coastline fills with water mayb a bay, long shore drift carries material across front of the bay swash brings it to the coastline and back wash back out to sea the deposited material eventually joins up with other side and blocks off bay.
E.g slapton sands

Question 20

26.Formation of tombolo

Answer 20

Usually forms from a spot that continues to grow seawards w until they reach to join an island.
Chelsie beach

Question 21

28.Types of delta

Answer 21

Deltas are large areas of sediment found at mouths of rivers, form when currents deposit sediment faster than removing it.
Cupsate
-pointed extension gentle currents and wind directions
Arcuate delta
-smooth pointed waves strong
Birds foot
-dirruibuted buyld out

Question 22

31.Raised beaches and marine terraces

Answer 22

RB- are areas of former shore platforms that are left T higher level than present sea level , often inland.
MT- larger landscape features. Whenever sea is stood with land the waves cut a terrace into the edge of the land.

Question 23

33.Submergent landforms -rias

Answer 23

Sectionswhere sea level rise inundated areas that were previously part of terrestrial land.
A ria is a drowned river valley. E.g Knightsbridge Devon.

Question 24

32.Formation of rias and fjords

Answer 24

RIAS- as sea level rises in warming climate the change causes the submerhent of a river valley either eustatic or isostatic. Low lying coastal environments are submerged. E.g Charleston harbour f
FJORDS- when sea level Rises and floods a deep glacial valley to create natural inlets deeper in the middle than at the mouth. E.h Milford on sea

Question 25

29.High energy coastal environment - salt burn to flamborough head

Answer 25

Geology- 60km long , chalk headland (flamboroughead) Energy- most exposed part of coast is North facing (salt burn) -areas of weak shale and clay, erosion rates 0.8m/year - Whitby bay wave height can eco creed 4m - LSD from N to S, is interrupted by headlands caring sand and shingle to accumulate to form beaches and bays like Filey Bay. Sediment sources- nearshore are driven onshore as sea levels rose last glacial period - increase in beach sediment of 9245m3 between 2008-11 at salt burn -Landforms Cliffs - salt burn Headlands- Ness point Bays - Filey Bay Shore platforms- robin hoods Bay Beaches-Filey Bay Blow holes- Selwicks bay Stack- green stacks pinnacle

Question 26

35.Hard engineering strategies with + and -

Answer 26

Sea walls+can last long and act as a promenade aswel.-very expensive £5000 per metre. Groynes+ cheap and and creates larger beach.- unattractive Rock armour+ cheap £1000 per metre .-makes access to beach difficult Gabions+blend in.-if damaged state can be a hazard for wildlife and people.

Question 27

34.Soft engineering +and -

Answer 27

Dune regeneration+looks natural and acts as buffer to sea .-time consuming Dine fencing+encourages new dune regeneration,protects dunes.-regular maintain w after storms managed retreat+ the alloweing of sea to flood or arode low level land.+natural and cheap Beach nourishment ,the adding of sediment to an eroding beach.+makes wider beaches.-expensive Beach re profile, sediment dristributed from low part to top,+cheap -needs to be repeated continuously.

Question 28

36.Sandbanks case study (coastal landscape management)

Answer 28

Current strategies - hold the line(maintains and sustain existing defences) Why need management? -high volume of commercial properties(hotel) -blue flag award (safe to swim) -sea level due to rise , expensive properties M management strategies -rock groynes- to maintain a wide beach, minimises sediment moved along beach due to LSD. -artificial rock pools- on sea wall sink basins, look like bubble wrap, home to crabs and snails=biodiversity -beach recharge- maintain wide and deep beach, sand from offshore sprayed onto beach, 3.5m m3 of sediment has been added to Poole bay beaches.

Question 29

37. Economic develope,not changes coastal landscapes (Sand mining at Mangawhai-Pakri New Zealand)

Answer 29

Economic development - sand is high quality for construction industry. 2015,2.3m visitors Off shore sand mining -currents rates of extraction=75,000m cubed a year,most of sand is used for replenishing Auckland’s tourist beaches Impacts on coastal landforms -beaches starved of sediment are wider but flatter so not absorbing waves -worries of flooding in harbour (so groyne construction) Long term retreat at the end of the century estimated width of 45-111metres.

Question 30

1.Coastal landscapes as open systems (def,components,feedback )

Answer 30

Open systems mean energy and matter can be transferred from one system to another. Inputs - kinetic, thermal and potential energy from weathering or mass movement. Outputs- marine , wind erosion and evaporation. Throuputs- stores like sediment on a beach and flows like LSD. If inpits and outputs are equal = equilibrium when the rate sediment is added to beach equals the rate sediment is taken from the beach. If something upsets the equilibrium the system changes and become a dynamic equilibrium going through negative feedback.

Question 31

5.How are waves formed

Answer 31

By the frictional drag of wind ,owing across the ocean surface, the higher the wind speed and longer the fetch the larger the waves and more energy they posses.

Question 32

7.Three types of breaking wave

Answer 32

Spilling- waves gently breaking and spilling into sloping beaches . Plunging - moderately steep waves breaking onto steep beaches, water plunging vertically down. Surging- low angle waves breaking into steep beaches, the wave slides forward.

Question 33

11. Sources of coastal sediment (terrestrial,offshore and human.)

Answer 33

Terrestrial sources contribute too the following processes: Fluvial deposition - erosion of inland areas by water,wind and ice , this sediment is carried to coast by rivers which deposit at their mouths and lose energy. Marine erosion- cliff erosion by waves can contribute to almost 70% of material on beaches. Aeolian deposition - wind carries small particles and deposit when lose energy. LSD- can supply sediment to another coastal area by moving it along the coast. Offshore Waves and wind can bring sediment from offshore locations. Marine deposition (waves eroding cliffs) Human Beach nourishment, added to beaches to protect from erosion, sediment bought from external sources.

Question 34

15. Mass movement

Answer 34

Rock fall- rocks on a cliff becoming detached due to physical weathering processes. Slide- movement taking place on perhaps bedding planes.

Question 35

23. Formation of cave,arch,stack,stump.

Answer 35

Wave refraction causes wave energy to focus on side of a headland.Points of weakness like faults or joints, can be exploited by hydraulic action (force cracks apart) and abrasion at the HWM and LWM, cave forms eventually break through to arch, the arch will continue to erode and get wider through attrition, roof falls due to gravity. rock type and structure can influence the speed of the erosion.

Question 36

27. Salt marshes

Answer 36

Low energy environments, vegetated areas, salt tolerant plant species like spartina help trap sediment to grow the marsh.

Question 37

30. Low energy coastal environment The Nile delta

Answer 37

Cause of low energy - rates of fluvial deposition has exceeded marine erosion for over 3,000 years. Facts- 6.650km, huge sediment load of 91.3 million, delay splits into distributaries , wave action has redistributed the sediment at front of delta. Costal landforms- tideless seas = underwater sand bars, headland( Abu Qir) , many beaches west with long bar system. Changes to sediment budget- Aswan High Dam built in 1964, before, 4m of thick layered silty mud deposited, now, reduced sediment , accelerated erosion and rising sea levels.