Coasts 🌊 Flashcards

Question

sediment budgets

Answer 1

the balance between inputs and outputs of sediment in a system (difference between them) can be positive (more enters, beach builds) or negative (more leaves, beach retreats) when balanced = dynamic equilibirum disturbed by climate change and human intervention

Answer 2

lengths of coastline (between 2 headlands or estuaries) that are closed coastal systems Mostly self contained movements of sediment (Sediment may move in strong waves)

Answer 3

rising sea levels and more frequent storms = more erosion more inputs of sediment glacial melt = more inputs

Answer 4

hard engineering prevent natural processes of erosion reduce outputs of sediment - traps it to build up beaches therefore reduces inputs of sediment down coast eg groynes in Happisburgh

Answer 5

focus on individual cells however advance and hold the line can impact inputs and outputs managed retreat and do noting can restore dynamic equilibrium

Answer 6

corrasion solution hydraulic action cavitation attrition wave quarrying

Answer 7

sediment transported by waves thrown against cliffs smash and rind against rock

Answer 8

soluble rocks get dissolved in seawater eg limestone

Answer 9

air in cracks in cliffs compressed by waves crashing pressure caused bits to break off, crack widens

Answer 10

waves receed, compressed air expands violently creates pressure bits break off, crack widens

Answer 11

rock and sediment in water smash against each other make smaller particles

Answer 12

energy of wave breaking on cliff breaks bits off

Answer 13

seaward dipping bedding planes - means loose material can slide down the bedding planes = less stable so more vulnerable landward dipping bedding planes = relatively steep and stable, less vulnerable

Answer 14

solution saltation traction suspension

Answer 15

substances are dissolved and carried in water eg limestone

Answer 16

very fine material carried along in water (above seabed) eg silt and clay

Answer 17

larger particles (can't be suspended) bounce along seabed by force of water eg pebbles and gravel

Answer 18

very large particles pushed along seabed (rolled) by force of water eg boulders

Answer 19

when material being transported is dropped on the coast

Answer 20

happens when sediment load exceed the ability of the water to carry it due to sediment load increases eg landslide water loses energy - friction increases, shallow water, slows - conflicting currents, slows

Answer 21

gradual breakdown of rocks in situ weakens cliffs, more vulnerable to erosion - chemical - biological - mechanical. freeze thaw, wetting and drying

Answer 22

breakdown of rocks by changing its chemical composition carbonation - carbon dioxide dissolves in rain to form acid rain - dissolves rocks containing calcium carbonate eg limestone solution - dissolved oxidation - iron minerals in rock react with oxygen and rust = breakdown

Answer 23

plant roots growing into cracks, widens animals building burrows

Answer 24

freeze thaw - happens where temperatures fluctuate around 0 - water enters cracks - freezes as it expands - overtime, weakens and breaks off wetting and drying - rocks that contain clay - gets wet, expands - creates pressure causing bits to break off Salt crystallisation - water collects in cracks - sun causes water to evaporate, leaves crystals - salt crystals bigger and grow = pressure in cracks so break up

Answer 25

movement of material downhill due to gravity unconsolidated rocks prone to collapse, less friction to hold together heavy rainfall saturates rocks, reduces friction runoff can also move fine sediment - creep - slide - slump - rockfall - mudflow

Answer 26

soil particles get wet less friction slowly move downslope

Answer 27

happens when wet, less friction downhill movement of material 'en masse' moves rapidly

Answer 28

softer material overlies more resistant material moves downhill creates a curved indented surface

Answer 29

rocks on a vertical cliff face mechanical weathering, weaken and dislodge rocks large parts breaks off and collect at bottom as scree

Answer 30

mud on a hill slope rainfall saturated soil, increases pressure and particles heavier sediment flows downhill

Answer 31

moves sediment along shore - swash carries sediment up beach at similar angle to prevailing wind - backwash moves sediment back down beach at right angles to shoreline = zig zag movement

Answer 32

transportation Erosion Deposition

Answer 33

weathering mass movement

Answer 34

rise or fall in sea level caused by a change in the volume of water in ocean basin - global effects

Answer 35

climate change/ice melt - increase in temperature - ice sheets melt - increases volume - levels rise - decrease in temperature - more precipitation falls as snow - increased storage in cryosphere - decreased volume - levels fall thermal expansion of water - warmer water expands - levels rise tectonic movements - alters shape of basin - mid ocean ridges, new land formed - displaces water - levels rise

Answer 36

rise or fall in sea level caused by vertical movements of the land relative to the sea - effects are local

Answer 37

glaciation causing depression of crust - weight of glaciers and ice presses down crust into asthenosphere - levels rise post glacial readjustment - uplift of earths crust as glaciers melt, asthenosphere rebounds - levels fall tectonic activity - causes land to move up or down

Answer 38

when sea levels fall relative to coast = emergent landforms raised beaches - beach above high tide mark, over time become vegetated marine platforms - exposed wave cut platforms relict cliffs - cliffs above raised beaches, no longer eroded by sea, exposed to weathering

Answer 39

when sea levels rise relative to coast = submergent landform rias fjords Dalmation Coastine

Answer 40

river valleys are partially submerged wide and deep at mouth, shallower inand much wider than natural river mouth eg Exemouth, River Exe

Answer 41

drowned glacial valleys eroded by glaciers in glacial times straight and narrow with steep sides very deep eg Sognefjorden, Norway

Answer 42

islands parallel to coastline caused by flooded valleys lying parallel to coast ridges at different heights, lower areas flooded and higher left exposed eg Dalmatian Coast, Croatia

Answer 43

glacial period, max 18,000 ya - more water stored in cryosphere - sea levels lower temperature increased, started 12,000 ya - ice melted - sea levels rose to current about 130m higher now since 1930, levels rising more - climate change

Answer 44

global warming - human activities, more greenhouse gases increased temperature - more thermal expansion - more ice melt (eustatic)

Answer 45

warmer tempertures = more frequent and intense storms - damage to coastal ecosystems and settlements rising SLs = more frequent and severe flooding - contamination of bodies of freshwater - damage to settlements - salinisation of soils, crop damage submergence of low lying islands

Answer 46

ICZM aims to restore equilibrium climate change = + feedback needs to be managed

Answer 47

if critical smaller than calculated = null rejected (there is a significant difference) if calculated smaller = null excepted (no significant difference)

Answer 48

erosion - hard rock (granite) more resistant than soft = discordant coastlines weathering - softer rock/ certain types more vulnerable to weathering - eg limestone and chemical mass movement - soft = more unconsolidated so more saturated when it rains = heavier so mass movement more likely transportation - more sediment to move deposition - more sediment = increased load = more deposition - scree at base of cliffs slows erosion to create deposition

Answer 49

erosion - high energy = more erosion as creates destructive waves - compared to more deposition at low energy weathering - more erosion = more cracks so more vulnerable to weathering mass movement - high energy = more vulnerable as material losened by erosion and weathering transportation - high energy = more movement of sediment deposition - high energy = less deposition, strong backwash - low energy = more deposition as less energy to carry

Answer 50

erosion - absorbs wave energy to reduce rates - can increase rates down coast weathering - protected from mechanical - but exposed to chemical and biological mass movement - cliffs more stable as eroded less, reduced risk - but still vulnerable after heavy rainfall, saturation transportation - groynes reduce movement by offshore drift deposition - some forms encourage deposition to protect cliffs and absorb energy - eg beach nourishment

Answer 51

weathering - creates cracks so more vulnerable mass movement - weakens and loosens material transportation - creates more sediment to move depostion - more sediment removed by destructive waves

Answer 52

erosion - more weathering = weaker and unconsolidated rocks = more vulnerable mass movement - less consolidated = more likely - means water can infiltrate transportation - create more lose material to be transported deposition - material collects at base of cliffs, slows waves = deposition