coasts

Question 1

what is a system?

Answer 1

a set of interrelated objects comprising of components (stores) and processes (links) that are connected together to form a working unit or unified whole

Question 2

types of energy in a coastal landscape system?

Answer 2

kinetic
potential
thermal

Question 3

are coastal landscape systems open or closed?
what does this mean w/ example

Answer 3

OPEN
energy and matter can be transferred form neighbouring systems as an input and transferred to neighbouring systems as an output
e.g. input of fluvial sediment from river

Question 4

inputs to a coastal landscape system

Answer 4

fluvial (river) sediment
KE from wind and waves
thermal energy from heat of sun
marine sediment deposited by the waves
weathered material from cliffs

Question 5

outputs of coastal landscape systems

Answer 5

evaporation of water
marine sediment eroded by waves
sediment eroded/taken away by wind

Question 6

stores of coastal landscape systems

Answer 6

beach
sand dunes
offshore bars

Question 7

flows/transfers of coastal landscape systems

Answer 7

movement of sediment along beach by LSD
wave movement on and off beach
wind blowing sediment

Question 8

what is equilibrium?

Answer 8

a long-term balance between inputs and outputs in a system

Question 9

example of equilibrium on a beach

Answer 9

happens when rate at which sediment is being added to the beach is equal to the rate at which sediment is being removed from the beach, so the beach remains the same size

Question 10

what happens when equilibrium is disturbed?
what is this known as?

Answer 10

system undergoes self-regulation and changes its form in order to restore the equilibrium
this is known as dynamic equilibrium, as the stem produces its own response to the disturbance; an example of negative feedback

Question 11

what is negative feedback?

Answer 11

an automatic response to a change in a system that restores equilibrium

Question 12

sediment cell definition

Answer 12

a stretch of coastline and its associated nearshore area within which the movement of coarse sediment, sand and shingle is largely self-contained

Question 13

is a sediment cell an open or closed system?
what does this suggest?

Answer 13

CLOSED
no sediment is transferred between cells

Question 14

how many sediment cells are in England and Wales
boundaries of these?

Answer 14

11
determined by topography and shape of coastline: large physical features e.g. lands end act as natural barriers that prevent transfer of sediment

Question 15

what affects the shape of coastlines?

Answer 15

geology
waves
wind
ocean currents
tides

Question 16

are sediment cells completely closed systems? why?

Answer 16

unlikely: variations in wind direction and presence of tidal currents mean it is inevitable that some sediment is transferred between neighbouring cells. input fluvial sediment too
depends on scale, since the major 11 cells contain many smaller sub-cells

Question 17

swell waves:
formed where?
wavelength/wave period?

Answer 17

formed in open oceans and can travel huge distances from where they are generated.
tend to have long wavelength and a wave period of up to 20 seconds

Question 18

storm waves:
formed where?
wavelength, height and wave period?

Answer 18

locally generated
typically have shorter wavelength, greater height and shorter wave period

Question 19

constructive waves charcteristics

Answer 19

low-energy wave
strong swash travels far up gradually sloping beach
lower height and frequency
pushes sand up shoreline, building up material and increasing the gradient
longer wavelength
summer months

Question 20

destructive waves characteristics

Answer 20

higher energy wave
stronger backwash- pulling material away from shoreline by erosion
greater height and frequency
removes material from top of beach and decreases gradient
moves sand to offshore zone
shorter wavelength
winter months

Question 21

significance of waves affecting coastal landscapes?

Answer 21

controls whether deposition/erosion dominate
changes diurnally and seasonally
small scale
controlled by wind

Question 22

aeolian effects on coastal landscapes

Answer 22

wave energy is produced through frictional drag of wind across ocean’s surface
higher windspeed and lower fetch lead to larger waves which possess more energy
onshore winds drive waves to the coast
wind blowing at oblique angle leads to waves approaching obliquely, leading to LSD
wind is a moving force so carries out erosion, transportation and deposition

Question 23

significance in wind affecting coastal landforms?

Answer 23

not that significant
key=wind determines waves
significance changed form day to day
in exposed places, wind has more significance than in sheltered places
small scale

Question 24

tidal impacts on coastline

Answer 24

generated by gravitational pull of the moon
tidal ranges are low in enclosed areas of sea (e.g. mediterranean)
smaller tidal ranges lead to more erosion bc waves are hammering smaller area more often and with more force
in areas with larger tidal ranges, deposition is dominant, so forms estuaries (e.g. Severn Estuary has large 14m tidal range bc water is funnelled)

Question 25

significance of tidal ranges on coastal landscapes?

Answer 25

account for lots of erosion over long time period determine whether erosive/ depositional landforms dominate larger scale

Question 26

ocean currents impact on coastlines?

Answer 26

generated by Earth's rotation and convection, and transfer heat energy change temp of water and air so affect weathering processes (increase sediment input) also affect input of sediment to a coastal system (dep. landforms/ sed. budget/ equilibrium affected) rip current caused by tidal motion or waves breaking and right angles to shore can form cusps (small scale)

Question 27

significance of ocean currents on coastlines?

Answer 27

large scale esp. significant in Western facing coastal landscapes bc driven by onshore winds cold ocean currents have less effect on landscapes bc they are driven by offshore winds affects sub-aerial processes, but not than significant

Question 28

what is lithology?

Answer 28

physical and chemical composition of rocks

Question 29

weak lithology with example

Answer 29

e.g. clay little resistance to erosion, weathering and mass movements weak chemical bonds between rock's particles

Question 30

strong lithology with example

Answer 30

e.g. basalt highly resistant, therefore more likely to form cliffs and headlands strong chemical bonds between rock's particles

Question 31

mineral composition of rocks and chemical weathering

Answer 31

rocks e.g. chalk and limestone have mineral composition which is soluble in weak acids so is easily weathered chemically e.g. by carbonation

Question 32

subtopics of geology structure

Answer 32

joints, cracks, faults rock permeability discordant vs concordant angle of dip

Question 33

what are joints, faults and cracks and how do they affect the shape of a coastline?

Answer 33

joints= fractures in rocks created without displacement some rocks e.g. limestone and chalk form with many joints and cracks, so erode at faster rates. this is apparent during differential erosion rocks with faults and cracks are easier for waves to erode because the wave energy can exploit these weaker points in the rock so lead to rapid erosion e.g. evolution of cave to stump

Question 34

what is rock permeability and how does it affect the shape of a coastline?

Answer 34

primary permeability= in porous rock e.g. chalk, tiny air spaces separate mineral particles. these pores can absorb and store water secondary permeability= Carboniferous limestone is permeable because water seeps into it because of its joints, which are enlarged by solution permeable rocks are less resistant to weathering

Question 35

how does discordance affect the shape of a coastline?

Answer 35

discordant= when rock strata lie at right angles to the coastline discordant planforms are created, which tend to have an alternating pattern of indented bays and projecting headlands due to the alternating bands of soft and hard rock

Question 36

how does concordance affect the shape of a coastline?

Answer 36

concordant= when rock starts that is uniform or runs parallel to coast tend to produce straight coastlines or small bays some have long narrow, islands parallel to the coastline

Question 37

how are angles of dip formed? what do they affect?

Answer 37

tectonic processes strength and steepness of cliff an likelihood of slipping. stronger=steeper

Question 38

describe each angle of dip.

Answer 38

HORIZONTAL= near-vertical profile with notches where rock is less resistant, so is exposed at the wave cut platform SEAWARD DIP=areas of overhanging rock, vulnerable to landslides, rock slides and sloping LANDWARD DIP= steep 70-80 degrees, very stable cliff, less rock falls

Question 39

significance of geology impacting coastal landscapes?

Answer 39

very significant on small scale determines shape of coastline and the landforms present long term

Question 40

3 main sources of sediment

Answer 40

terrestrial (from the land) offshore (from the sea) human (deliberate)

Question 41

examples of terrestrial sediment

Answer 41

fluvial (rivers) cliffs

Question 42

examples of offshore sediment

Answer 42

offshore bars ocean currents longshore drift

Question 43

examples of human sediment sources

Answer 43

beach nourishment/replenishment rain bowing (adding sediment to beaches that are in sediment deficit)

Question 44

terrestrial sediment source: fluvial where? when? how much?

Answer 44

rivers are major sources of sediment into the coastal sediment budget (particularly true of coasts with a steep gradient where rivers directly deposit their material at the coast) sediment delivery to the shoreline can be irregular/intermittent, mostly occurring during floods in some locations, 80% of sediment is fluvial

Question 45

terrestrial sediment source: cliffs how and when? how much?

Answer 45

origin of sediment is the erosion of inland areas by water, wind, ice and sub-aerial weathering wave erosion is also the source of lots of sediment cliff erosion is increased by rising sea levels and is amplified by storm surges (can contribute 70% of overall material; although typically less), can be large rocks if directly from collapse of cliffs

Question 46

offshore sediment source: wave transport

Answer 46

constructive waves bring sediment to the shore from offshore locations and deposit it (marine deposition), adding to the sediment budget. tides and current do the same.

Question 47

terrestrial sediment source: aeolian processes what type of sediment and where?

Answer 47

wind also blows sediment from other locations, including exposed sand bars, dunes and beaches elsewhere along the coast. this aeolian material is generally fine sand, as wind has less energy than water and so cannot transport very large particles

Question 48

terrestrial sediment source: longshore drift

Answer 48

supplies sediment from one coastal area by moving it along the coast to adjacent areas

Question 49

human sediment source: beach nourishment and rainbowing how? why?

Answer 49

has been adopted all over the world in order to preserve and protect the coastal environment sediment can be brought in by lorry and dumped on the beach before being spread out by bulldozers. alternatively, sand and water can be pumped onshore by pipeline from offshore sources. low bunds hold the mixture in place while the water drains away, leaving the sediment behind

Question 50

how to work out if the sediment budget is in surplus, deficit or equilibrium

Answer 50

wind, waves and LSD can remove sediment from the budget. by subtracting the amount of sediment lost from the sediment gained, it can be determined if the oddment budget is in equilibrium, surplus or deficit

Question 51

what could affect the relative significance of different sources of sediment?

Answer 51

resistance of coastal rock types & fluvial sediment (geology) how sheltered/exposed the beach is and its geographical location wind strength presence of a river wave strength

Question 52

key processes in a costal environment with an example

Answer 52

mass movement events e.g. landslides sub-aerial weathering e.g. freeze thaw transportation e.g. LSD deposition e.g. waves lose energy and drop material erosion e.g. abrasion

Question 53

flows of energy in a coastal landscape

Answer 53

kinetic energy of wind and waves thermal energy e.g. sun dries out sand so its easier to transport and drives currents&winds GPE causes mass movement and backwash

Question 54

flows of material in a coastal landscape

Answer 54

aeolian flows can move sediment from beach to sand dune fluvial provide lots of sediment so depositional features often dominant around river mouths LSD moves sediment along beach and between beaches mass movement events e.g. rockfalls and landslides

Question 55

what percentage of sediment comes from rivers in a coastal landscape?

Answer 55

70-80%

Question 56

direction of LSD in the UK

Answer 56

N to S in NE UK W to E in SW UK

Question 57

difference between erosion and sub aerial weathering?

Answer 57

erosion= wearing away and/or removal of rock/other material by a moving force sub-aerial weathering= a collective term for weathering(breakdown of material in situ) & mass movement processes

Question 58

under what 5 conditions does deposition occur?

Answer 58

when rate of sediment accumulation exceeds the rate of removal when waves slow down immediately after breaking at top of swash, where water is no longer moving for a brief moment during backwash when water percolates into the beach material in low-energy environments, sheltered from wind and waves e.g. estuaries

Question 59

what is the settling velocity?

Answer 59

the velocity at which sediment particles are deposited

Question 60

what is a mass movement event?

Answer 60

occurs when forces acting downwards on slope material (mainly resultant force of gravity) exceed the forces trying to keep the material on the slope (predominantly friction)

Question 61

what are the most significant mass movement events in a a coastal landscape?

Answer 61

those acting on cliffs lead to addition of material to sediment budget by transferring rocks & regolith onto shore below

Question 62

what is flocculation?

Answer 62

a process buy which salt causes the aggregation of minute particles (e.g. clay) into larger masses that are too heavy to remain suspended in the water, so are deposited

Question 63

where does flocculation occur?

Answer 63

where fresh and salt water occur e.g. river mouths/ estuaries

Question 64

freeze thaw weathering description

Answer 64

water enters cracks/joints and expands by 10% when it freezes in confined spaces this exerts pressure on the rock, causing it to split/ pieces break off even occurs in resistant rocks

Question 65

solution weathering description

Answer 65

some salts are soluble in water. other minerals (e.g. iron) are only soluble in very acidic water (pH3) any process by which a mineral dissolves in water is known as solution, although mineral specific processes (e.g. carbonation) can be identified

Question 66

tree root weathering description

Answer 66

tree roots grow into cracks or joints in rocks and exert pressure outward (operates in a similar way and with similar effects to freeze-thaw) when trees topple, their root can also exert leverage on the rock/soil, bringing them to the surface and exposing them to further weathering burrowing animals may also have the same effect particularly significant on cliff tops/ cliff faces

Question 67

abrasion description

Answer 67

when waves armed with rock particles scour the coastline; rock rubbing against rock

Question 68

attrition description

Answer 68

when rock particles, transported by wave action, collide with each other and with coastal rocks and progressively become worn away they become smoother, smaller and rounder, eventually producing sand

Question 69

hydraulic action description

Answer 69

when waves break against a cliff face, and air and water trapped in cracks and crevices becomes compressed. as the wave recedes, the pressure is released the air and water suddenly expands and the crack is widened

Question 70

pounding description

Answer 70

when the mass of a breaking wave exerts pressure on the rock, causing it to weaken. forces as much as 30 tonnes per m^2 can be exerted by high-energy waves

Question 71

force exerted by high-energy waves?

Answer 71

as much as 30 tonnes per m^2

Question 72

corrosion/ solution (erosion) description

Answer 72

involves dissolving minerals (e.g. MgCO3) in coastal rock. however, because pH of seawater is around 7 or 8, this process is usually less significant (unless water is locally polluted or acidic. even then, only coastal rocks containing significant amounts of soluble materials are likely to be affected by this)

Question 73

suspension description

Answer 73

small particles of sand, silt and clay can be carried by currents (accounts for brown/muddy appearance of some sea water) larger particles can also be carried in this way (esp. during storm events)

Question 74

traction description

Answer 74

largest particles in the loads may be pushed along the sea floor by the force of the flow (can be called rolling but movement is seldom continuous) large boulders may undertake a partial rotation before coming to rest again

Question 75

saltation description

Answer 75

a series of irregular movements of material which is too heavy to be carried in suspension continuously turbulent flow may enable sand-sized particles to be picked up (entrained) and carried for a short distance then dropped back down again similarly, other particles may be dislodged by the impact, allowing water to get beneath them and cause entrainment.

Question 76

solution transportation description

Answer 76

minerals that have been dissolved into the mass of moving water. this type of load is invisible and the minerals will remain in solution until water is evaporated and they precipitate out of the solution

Question 77

what are aeolian processes?

Answer 77

erosional, transportation and depositional processes by the wind

Question 78

aeolian erosion description

Answer 78

wind picks up sand particles and moves them by deflation. 40km/h erosive force increases with wind velocity attrition is more effective than in water because there is no protection

Question 79

aeolian transportation description

Answer 79

particles are entrained, carried, saltated or moved by surface creep. 40km/h smallest grains are carried in suspension

Question 80

aeolian deposition description

Answer 80

material is deposited when wind speed falls, usually due to surface friction inland where friction increases due to vegetation and surface irregularities-> forms sand dunes

Question 81

what sort of sand is transported most easily by aeolian processes?

Answer 81

dry sand bc its much easier for wind to pick up than wet sand bc moisture increases cohesion between particles so they stick together smaller grains can be carried in suspension, but most cannot so this limits erosion to about 1m high (limits effects on rocky cliffs/coastlines)

Question 82

when does longshore drift occur? describe process of LSD

Answer 82

when waves approach the coast at an angle due to the direction of the prevailing wind when the waves have broken the swash carries particles diagonally up the beach under the influence of gravity, the backwash moves them perpendicularly back down the beach. if this movement is repeated, the net result is a movement of material down the beach also leads to attrition of beach sediment so particles become smaller w/ increasing distance along the beach

Question 83

rockfall description where are they common? what are they triggered by?

Answer 83

sudden collapse or breaking away of individual rock fragments or a block of rock at a cliff face. these rocks fall or bounce down slope to form scree (temp. store) steep/vertical cliffs in heavily jointed & resistant rock mechanical weathering e.g. freeze-thaw or an earthquake

Question 84

mudflow description what type of bedrock?

Answer 84

sudden and fast-flowing earth and mud flowing downhill, often after heavy rainfall. water gets trapped in rock, increasing pore water pressure, so rock particles are forced apart and slope failure is caused unconsolidated/weak bedrock e.g. clay

Question 85

what is pore water pressure?

Answer 85

a form of energy within the slope system is v important factor in determining slope instability

Question 86

landslide description what are they often triggered by?

Answer 86

a block of rock moving v. rapidly downhill along a planar surface, often a bedding plane that is parallel to the ground surface. this block remains largely intact triggered by earthquakes and v. heavy rainfall bc slip surface becomes lubricated and friction is reduced

Question 87

landslip/ slump description occurs in which rock types? what are they characterised by?

Answer 87

rock moving downhill rapidly along a curved slide surface weak and unconsolidated clays and sands, often where permeable rock overlies impermeable rock, causing a buildup of pore water pressure a sharp break of slope and the formation of a scar. multiple car result in terraced appearance on cliff face

Question 88

soil creep description movement direction? charcateristics?

Answer 88

extremely slow movement of individual soil particles downhill. often involves particles rising towards surface due to wetting/freezing, then returning vertically to surface in response to gravity as soil dries/thaws zigzag movement forms shallow terracettes, builds up soil on the upslope side of walls and bending of tree trunks

Question 89

solifluction description specific to which environments? forms what

Answer 89

in summer, surface layer of soil thaws and becomes v. saturated bc it lies on top of impermeable permafrost. known as the active layer, this soil w/ vegetation moves downhill by a combination of heave and flow cold periglacial environments solifluction lobes

Question 90

significance of mass movement at the coast

Answer 90

add sediment to the system rapidly changes coastline significantly

Question 91

what is wave refraction? when does it take place?

Answer 91

reorientation of wave fronts as they enter shallow water so that they are about parallel to the shoreline when waves approach an irregularly shaped coastline (particularly on coastlines with bays and headlands- discordant)

Question 92

description of how wave refraction takes place

Answer 92

as each wave nears the coastline, it is slowed by friction in the shallower water off the headland at the same time, the part of the wave crest in the deeper water approaching the bay moves faster bc it is not being slowed by friction wave bends/refracts around the headland and the orthagonals converge wave energy and erosive power focused and concentrated on headland ->caves,arches,stacks,stumps orthagonals diverge in bays and the energy is dissipated so deposition takes place longshore movement of eroded material into bays bc waves break onto headland at an angle -> build-up of beach sediment

Question 93

what are orthagonals?

Answer 93

imaginary lines perpendicular to wave fronts, representing transfer of energy as waves form towards coasts

Question 94

where do swash aligned beaches form which waves are here?

Answer 94

in low-energy environments e.g. bays which are affected by waves arriving roughly parallel to the shore

Question 95

where do drift-aligned beaches form what process affects the beach profile?

Answer 95

where waves approach the beach at an angle. longshore drift moves sediment along the beach culminating in the formation of a spit

Question 96

what landforms are associated to swash-aligned beaches

Answer 96

cusps, berms, ridges, runnels bayhead beaches (curved beaches formed at the back of bays) cave to stump formation on headlands of bay head beaches

Question 97

what landforms are associated with drift-aligned beaches

Answer 97

spits, bars, tombolos beaches that run parallel to the coast

Question 98

example of a beach

Answer 98

Filey Bay, Yorkshire 5 miles wide

Question 99

where do beaches form and what do they represent?

Answer 99

formed in bays where there are shallower waters and more sheltered conditions represent accumulation of material deposited between lowest tides and highest storm waves

Question 100

how do beaches form?

Answer 100

constructive waves have a stronger swash than backwash, so carry sediment up the beach and then deposit it, because they percolate or lose energy through friction

Question 101

where do ripples form and why?

Answer 101

further down a beach from cusps, develop in the sand due to the orbital movement of water in waves

Question 102

how do longshore bars and runnels form on beaches?

Answer 102

at the lower edge of beaches, sand accumulates to form longshore bars parallel to the waves material has been combed by plunging destructive waves breaks in these ridges result from rip currents which form in the strong backlogs, inland of these runnels form

Question 103

what are cusps? how do they develop?

Answer 103

small, semi-circular depressions temporary features formed by a collection of waves reaching the same point and when the swash and backwash have similar strength the sides of the cusp channel incoming swash into the centre of the depression, producing a strong backwash, which drags material down the beach from the centre of the cusp, enlarging the depression

Question 104

what are berms?

Answer 104

small ridges that develop at the position of the mean high tide mark, resulting from deposition at the top of the swash

Question 105

how does a storm beach/storm ridge form?

Answer 105

storm waves hurl pebbles and cobbles to the back of the beach

Question 106

swash aligned vs drift aligned beaches

Answer 106

swash aligned beaches are more influenced by constructive wave patterns, which are also important for building up large beaches drift aligned coasts bring in waves at an angle to the shoreline and so therefore, the waves tend to transport sediment down the coast, keeping beaches relatively narrow

Question 107

what sort of material do beaches contain and where does it come from?

Answer 107

material consists of sand, pebbles & cobbles from cliff erosion, offshore sources and rivers

Question 108

what are spits and where do they form?

Answer 108

long, narrow beaches of sand or shingle that are attached to the land at one end and extend across a bay, estuary or indentation in the coastline

Question 109

how do spits form?

Answer 109

when LSD occurs in one dominant direction & carries beach material to the end of the beach then beyond into the open water storms build up larger material to make the spit a more permanent feature end of spit often becomes recurved as a result of wave refraction around the end ion the spit or a 2nd wave direction multiple recurves form over time and become extended size is limited if the spit is across an estuary due to the flow of the river's current

Question 110

spit example

Answer 110

Orford Ness, East Anglia 10 miles long

Question 111

what are onshore bars?

Answer 111

linear ridges of sand/shingle extending across a bay, connected to land on both sides

Question 112

how do onshore bars form?

Answer 112

can develop if a spit continues to grow across an indentation e.g. bay, cove in the coastline until it joins onto the land at the other end they trap a body of seawater behind them, forming a lagoon

Question 113

what is flandrian transgression?

Answer 113

a period of rapid sea level rise where sediment is driven form offshore sources by waves so a ridge of sediment forms can form onshore bars

Question 114

onshore bars example

Answer 114

slapton sands, devon 4km long

Question 115

what are tombolos?

Answer 115

beaches that connect the mainland to an offshore island

Question 116

tombolo formation by spit extension

Answer 116

formed from spits that have continued to grow seaward until they reach and join an island LSD occurs and waves push sediment at an angle so the beach builds up between the mainland and island

Question 117

tombolo formation by wave refraction and diffraction

Answer 117

waves are slowed down as they enter shallower water around islands, so are refracted around the island, pick up sediment and then deposit it where the waves meet (on the side facing the coast) this sediment builds up and a sand bar is created joining the island and beach

Question 118

example of a tombolo

Answer 118

chesil beach dorset= spit extension st ninians, orkneys= wave refraction 500m long

Question 119

how are salt marshes formed?

Answer 119

as wave energy is reduces, deposition occurs in sheltered areas. this deposited material e.g. salt and mud builds up, and can result in the growth of salt-tolerant vegetation e.g. eelgrass. the roots of these plants traps sediment so increases the height of the marsh flocculation aids formation

Question 120

where do salt marshes form?

Answer 120

in estuaries and on the landward side of spits

Question 121

what is flocculation

Answer 121

salt causes aggregation of small particles e.g. clay into larger particles (flocculation) which are too heavy to be carried in the river flow, so settle out of suspension and are deposited

Question 122

daily changes in salt marshes?

Answer 122

subjected to inundation and exposure twice daily as tides rise and fall

Question 123

example of salt marsh

Answer 123

Abel tasman, New Zealand

Question 124

characteristics of a cliff

Answer 124

usually at a steep angle of over 40 degrees but may also be vertical or overhanging often found on the coast with a shore platform below

Question 125

how are cliffs created?

Answer 125

when destructive waves repetitively break on relatively steep sloping coastlines, undercutting can occur between the high and low tide levels, forming a wave cut notch continued undercutting of the notch weakens support for the rock strata above, which eventually collapses and produces a steep profile and a cliff the regular removal of material at the base of the cliff by waves means that the cliff profile remains steep and the cliff retreats inland parallel to the coast

Question 126

how are cliff profiles affected by geology?

Answer 126

ANGLE OF DIP chemical composition

Question 127

how do cliff profiles vary with angle of dip?

Answer 127

HORIZONTAL= steep, almost vertical profile which follows the angle of the dipping strata, parallel to coast, at the base, a gentle sloping shore platform is cut into the solid rock (attacked by abrasion as debris is carried across the surface by wave action), when a rock platform is created due to the rocks being too large to be removed, friction on the platform slows down approaching waves so they break on the platform (rather than the cliff), so undercutting & erosion decreases SEAWARD= undercutting removes basal support, vulnerable to rockslides, only one rock type facing the sea, lose material easier as it moves down the 45 degree slope into the sea as rock layers loosen in mass movements LANDWARD= rocks loosened by weather and difficult to dislodge due to the gravitational force pulling them back into place, few rock falls due so the stable profile 70-80 degree slope,

Question 128

processes contributing to cliff formation besides erosion (main one)

Answer 128

mass movement events e.g. rockfalls weathering processes e.g. solution, freeze-thaw, salt crystallisation (depends on geology & climate) when platform is exposed at low tide, marine organisms e.g. algae increase weathering because they release CO2 at night (no p/s can take place), which mixes with seawater, making it more acidic and increasing chemical weathering

Question 129

where do rock pools form?

Answer 129

shore platform with a slope of 0-3 degrees which are covered at high tide marine animals e.g. crabs get trapped so don't return back to sea

Question 130

how do wave cut platforms form?

Answer 130

rock debris eroded from cliffs (collapsing) which is too large to be carried away by wave action often accumulates on the shore platform eventually the platform becomes so wide that it produces shallow water and small waves friction from the platform slows down approaching waves sufficiently for them to break on the platform rather than at the base of the cliffs (platform acts as a wave break and absorbs all the energy from the sea processes) undercutting slows and eventually ceases

Question 131

what must the geology be for a shore platform to form?

Answer 131

horizontally strataed

Question 132

what is cliff recession/shore platform formation an example of?

Answer 132

negative feedback

Question 133

where do bays and headlands form?

Answer 133

adjacent to each other on discordant coastlines (rock lying parallel to coastline) rocks have differing resistance to erosion

Question 134

how do bays and headlands form on discordant coastlines?

Answer 134

less resistant rocks are eroded more rapidly to form bays while the more resistant rocks remain between bays as headlands WAVE REFRACTION leads to increased rates of differential erosion

Question 135

what determines the width of bays? what determines the depth of bays?

Answer 135

the width of the band of weaker rock the differential rates of erosion between more/less resistant rocks

Question 136

how do bays and headlands form on concordant coastlines?

Answer 136

if the more resistant rock lies on the seaward side, it protects any weaker rocks inland from erosion the resultant coastline is quite straight/even, but small bays or coves may occasionally be eroded ar points of weakness e.g. fault lines

Question 137

flows of energy and materials in formation of bays and headlands

Answer 137

energy: kinetic energy of waves and wind (bay waves have lower energy and headland wave shave higher energy) material: lower energy bay waves (constructive) deposit sand onto section of the beach, sediment is eroded off headlands by high energy waves (destructive)

Question 138

why is there not a huge difference between the headland and bay?

Answer 138

sediment eroded from the headland is deposited in the bay (NEGATIVE FEEDBACK)

Question 139

what is a geo?

Answer 139

an inlet, a gully or a narrow, deep cleft in the face of a cliff with steep sides

Question 140

width of a geo?

Answer 140

a few feet to hundreds of feet wide usually only 10-20m wide

Question 141

what are geos created by? (brief)

Answer 141

wave driven erosion along faults and bedding planes in rock in the face of a cliff

Question 142

what is a blowhole?

Answer 142

a vertical fault which has been widened by wave attack between a tunnel-like cave and the cliff top

Question 143

requirements for a geo to form?

Answer 143

the faults must be 70 degrees to 90 degrees to the coastline

Question 144

example of a geo

Answer 144

huntsman's head geo, Pembroke, Wales 4m at its smallest and 40m at its widest often used for rock climbing and thrill seekers who jump over it

Question 145

flows of energy in evolved in forming a geo/blowhole

Answer 145

KE of waves and wind eroding the cliff face GPE eroding the fault from above, causing the roof to collapse once the blowhole collapses, KE is lost (wave power is lost so not enough energy left to erode) so the geo won't get much bigger; will only widen slightly due to weathering

Question 146

what is the main form of erosion that takes place in the formation of geos/blowholes?

Answer 146

hydraulic action as the high pressure from the rapid wave action targets the mega fault, making it weaker also forces air/water into the fault, further weakening the rock strata

Question 147

processes involved in the formation of a geo/blowhole

Answer 147

erosion of fault/mega fault by HA, abrasion, solution, pounding weathering on top of the cliff e.g. freeze thaw, helping to erode the fault from above these processes take place over a long time weakening the fault, but a particularly strong storm could cause the roof to collapse

Question 148

evolution of a geo?

Answer 148

fault erodes to cave if part of the roof collapses along the joint, forming a vertical shaft, a blowhole is formed if the WHOLE roof collapses it forms a geo

Question 149

geology affecting a geo rock type? strata? discordance/concordance?

Answer 149

the rock face is usually hard resistant rock e.g. limestone, which has a mega fault that causes its line of weakness the rock face could have bedding planes (horizontal layers) within the rock as cracks and faults are commonly found in these discordant/concordant planforms do not affect geos

Question 150

how does a geo actually form?

Answer 150

rock face has lines of weakness e.g. joints/faults these weak points are eroded more rapidly by wave action than the more resistant rock around them HA is particularly important in forcing air and water into the joints and weakening the rock strata sometimes initially form as tunnel-like caves at 90 degrees to cliff line, which become enlarged by continuing erosion, and roof collapse forms a geo if only PART of the roof collapses, forming a vertical shaft that reaches the cliff top, a blowhole id formed

Question 151

what may geos be associated with in Cornwall and what are they called?

Answer 151

zawns associated with old tin mining shafts

Question 152

blowholes characteristics in storms

Answer 152

large waves may force spray out of blowhole as plumes of white, aerated water during storms

Question 153

requirements for caves/arches/stacks/stumps to form?

Answer 153

discordance (creates the headland) high energy waves for erosion (high flows of energy are required) rocks with joints/faults/cracks so differential erosion can take place e.g. limestone or chalk refraction of waves

Question 154

why is wave refraction required for the formation of caves/arches/stacks/stumps?

Answer 154

focusses energy around the headland differential erosion of the headland can occur because there is enough erosive power, so the lines of weakness are exploited more

Question 155

examples of cave/arch/stack/stump evolution

Answer 155

Old Harry Rocks, near Swanage Ko Tapu

Question 156

where do caves form on the headland?

Answer 156

where the wave attack is focussed; between high and low tide levels where there are points of weakness

Question 157

step by step formation of cave/arch/stack/stump

Answer 157

due to wave refraction, energy is focussed on side of headland points of weakness are exploited by erosion processes small cave may develop on one or both sides of headland between high and low tide levels if a cave enlarges so that it extends through to the other side of the headland, an arch is formed erosion widens the arch and weakens its support, along with weathering processes arch may collapse, leaving an isolated stack separated from the headland further erosion at the base of the stack may eventually cause further collapse leaving a small, flat portion of the stack as a stump (may only be visible at low tide)

Question 158

case study of a high energy coastline??

Answer 158

flamborough head to saltburn, NE England

Question 159

physical factors influencing the landforms between flamborough head and saltburn

Answer 159

geology wave energy sediment supply

Question 160

rate of erosion in chalk and limestone

Answer 160

0.1m/year

Question 161

rate of erosion in Lias and shale?

Answer 161

0.8m/year

Question 162

wave direction/direction of prevailing wind at flamborough head to saltburn coastline

Answer 162

northerly winds

Question 163

length of fetch at flamborough head to saltburn coastline?

Answer 163

1500km

Question 164

direction of LSD on flamborough head to saltburn coastline

Answer 164

north to south

Question 165

name of river on flamborough head to saltburn coastline and its sediment input? why?

Answer 165

river Ask minimal sediment input because it is a heavily managed river

Question 166

how is geology linked to stacks/stumps

Answer 166

discordant coastlines create layers of hard and soft rocks this means that headlands stick out (harder rock) over time, these can be eroded by high energy waves refracting and creating stacks and stumps e.g. Green Stack at Flamborough Head

Question 167

how is wave energy linked to stacks/stumps

Answer 167

high energy waves from North (1500km fetch) erodes stacks

Question 168

how is wave energy linked to shore platforms

Answer 168

high energy waves from North erodes the softer rock in the shore platform e.g. Robin Hood's Bay

Question 169

how are shore platforms linked to cliffs

Answer 169

shore platforms act as wave breaks for cliffs so slow the rate of erosion shore platform forms as cliff erodes where there are horizontally bedded layers of hard/soft rock

Question 170

how are cliffs related to bays flamborough head to saltburn

Answer 170

cliffs made of LIAS rocks erode at 0.8m/year so supply the most sediment to bays

Question 171

how are rivers linked to bays flamborough head to saltburn

Answer 171

not many rivers so less sediment input therefore there are small bays or beaches

Question 172

how are headlands linked to bays flamborough head to saltburn

Answer 172

as bay retreats, headland acts as a wave break and energy is focussed on headland due to wave refraction therefore less energy in the bay so deposition takes place e.g. Filey Brigg/Filey Bay

Question 173

examples of cliffs on flamborough head to saltburn coastline

Answer 173

cliffs at flamborough cliffs at robin hoods bay and saltburn

Question 174

example of shore platform on flamborough head to saltburn coastline

Answer 174

shore platform at robin hoods bay

Question 175

example of beach on flamborough head to saltburn coastline

Answer 175

saltburn beach

Question 176

example of arch on flamborough head to saltburn coastline

Answer 176

arch at selwick bay

Question 177

examples of bays on flamborough head to saltburn coastline

Answer 177

robin hoods bay Filey bay

Question 178

example of headland flamborough head to saltburn rock type formation

Answer 178

flamborough head= large chalk headland cliffs have till on top, a superficial deposit left behind by glaciers during the Devensian glacial period

Question 179

cliffs at flamborough: rock type, height, angle change over time?

Answer 179

chalk; strong 20-30m high vertical but the top of the cliffs (composed of till) are lowered by mass movement so have an angle of 40 degrees lower part= strong rock w/ tightly bonded material so is slow to erode via marine processes cliff collapse is most likely but this will be a slow process (probably in storm) upper half is weaker so prone to biological weathering and mass movement (slumping, slipping). erosion here more extensively in winter than summer

Question 180

cliffs at Robin Hood's Bay geology change over time?

Answer 180

stepped profile due to more varied geology. steeper areas= sandstone and limestone horizontal bedding planes here (stronger rocks interspersed by weaker rocks); weaker rocks subject to more weathering & erosion so slumping is more common. therefore angle of cliff not as steep will retreat more quickly than flamborough head cliffs erosion more extensive in winter than summer

Question 181

shore platform at robin hoods bay angle, width, when was it formed? change over time?

Answer 181

1 degree max. width of 500m formed within last 6000 years as shore platform grows, it acts as its own breakwater so waves will erode shore notch making platform bigger at a slower rate therefore shore platform does not grow as quickly, unless sea levels rise so waves can reach base of cliffs more regularly

Question 182

Filey bay geology change over time?

Answer 182

eroded in to weak kimmeridge clay more resistant limestone and chalk either side forming the headlands bay accumulates sediment during summer constructive waves and loses sediment in winter months due to storms/destructive waves dynamic equilibrium exists to keep beach roughly the same size

Question 183

beach at saltburn sediment levels accumulation of sediment? change over time?

Answer 183

net increase of sediment of 9245m3 between 2008 and 2011 rare example along this coastline as waves usually erode sediment before accretion (accumulation can take place) loses sediment in winter months due to storms and destructive waves

Question 184

green stacks pinnacle and arch at selwick bay formation rock type change over time?

Answer 184

as a result of wave refraction, wave energy becomes v concentrated I flamborough head; has left stack isolated at the end where HA has opened up a joint and an arch next to it chalk over time, it will collapse to form a stump; probably during a winter storm after years of erosion arch will eventually collapse to form a stack

Question 185

robin hoods bay rock type change over time?

Answer 185

eroded into lower Lias shales stronger bands of sandstone to north (ness point) and south (ravenscar) forming the 2 headlands bay accumulates sediment during summer constructive waves and loses sediment in winter months due to storms/destructive waves dynamic equilibrium exists to keep beach roughly the same size

Question 186

example of stack on flamborough head to saltburn coastline

Answer 186

Green Stacks Pinnacle

Question 187

points in question: 'explain the role of flows of energy in the formation of stumps(8)'

Answer 187

form on discordant coastlines bc headland sticks out as more resistant rock. destructive waves necessary wave refraction= energy conc. on sides of headlands wave exploit weaknesses e.g. joints and faults (more common in chalk/limestone) and erode into a cave waves erode through headland, opening up cave into an arch HA and abrasion from high-energy waves (flow of energy) along with freeze thaw and biological weathering of top of arch causes it to collapse (GPE pulls it down) to form a stack destructive waves form wave cut notch in stack at base, which collapses to form a stump when support is lost (1/3 of height of cliff) changes to these landforms will change v quickly after a storm/high energy event

Question 188

points in question: 'explain the roles if flows of energy in the formation of geos(8)'

Answer 188

geo= an inlet/gully/narrow & deep cleft in face of a cliff between a metre and 100s of feet wide can recede up to 50m back formed in resistant rock (e.g. limestone) cracks and faults common due to horizontal bedding planes cave= formed where there is a fault/megafault at 70-90 degrees to cliff bc rock is weaker so can be eroded by waves & HA/abrasion freeze-thaw weathering & biological weathering erode top of cliff, causing part of the roof of cave to collapse and form a blowhole if KE from waves continues to weakens and erode rock, whole roof collapses to form geo

Question 189

points in question: 'explain the roles of flows of energy in the formation of shore platforms(8)'

Answer 189

shore platforms= horizontal/gently sloped rock (0-3 degrees) at base of cliffs (usually cliffs are at steep angel of >40 degrees but may be vertical/overhanging) required horizontally bedded rocks high KE of wind and waves form destructive waves, which repeatedly hit steep coastline, forming a wave cut notch between high and low tide levels over a long period of time. notch increases in size, decreasing stability of cliffs bc undercutting weakens rock strata cliff collapses due to GPE and retreats high energy waves remove material from base of cliff, leaving profile parallel to coast over time, this process repeats, building up forming a wave cut platform in the areas of cliff recession NEGATIVE FEEDBACK LOOP- as platform grows, it acts as a wave break which slows down rate of growth of platform

Question 190

points in question: 'explain the impact of geology on coastal landscapes(8)'

Answer 190

lithology/structure: discordance/concordance, where differential erosion affects the shape of the coastline discordant coasts (e.g. st davids bay, Pembroke), have alternation pattern of bays/headlands due to bands of hard/soft rock. concordant coasts (e.g. lulworth cove) lie parallel to trend of geology, so from bays and coves and form straight coastlines joints(found in chalk/limestone)= easier for waves to erode due to waves easily exploiting weaker points->differential erosion. therefore evolution of cave->stump and, where there is a megafault, blowhole and geo angle of dip: horizontal=weak strata exposed so eroded so wave cut notch & platform form seaward= vulnerable to rockslides bc bonds between strata are weak landward= v. stable w/reduced rock falls

Question 191

points in question: 'formation of bays and headlands(8)'

Answer 191

headlands formed when waves erode discordant coastline alternating bands= differential erosion e.g. HA and abrasion of high-energy, destructive waves (KE) harder rock juts out so wave refraction occurs, which acts as a negative feedback loop as it speeds up rate of erosion of headland and encourages deposition in bays

Question 192

width of Nile delta and what type of delta is it? population?

Answer 192

240km wide arcuate delta majority of Egyptian population lives here

Question 193

Nile distributaries names

Answer 193

Rosetta and Damietta

Question 194

Nile delta examples of: spit bar lagoon sand dune crescentic bar

Answer 194

Damietta spit Rosetta onshore bar Manzala and Burullus lagoons Gamsa sand dunes Crescentic bars at Alexandria

Question 195

Nile delta direction of LSD

Answer 195

West to East

Question 196

example of hard engineering in Nile Delta why?

Answer 196

at Alexandria there was a spit forming here but significant hard engineering strategies have been employed to control the rates of deposition & erosion in the coastal system due to the high value land in the area

Question 197

key historic reasons for Nile delta's morphology

Answer 197

sediment supply coastal processes

Question 198

historic sediment supply causing Nile deltas morphology

Answer 198

delta formation needs consistent sediment supply Nile=longest river in world: 120 million tonnes of sediment was transported annually river traditionally flooded annually, and these floods deposited vast amounts of sediment on the delta flood plains -> fertile soils sediment not deposited on plains reached mediterranean and was deposited bc of flocculation -> deposition focussed around mouths of distributares

Question 199

depth of fertile soils around Cairo

Answer 199

up to 9.6m

Question 200

why is the mediterranean a low energy environment?

Answer 200

short fetch of waves lack of tidal range storms are rare (high-energy coastal events are rare too)

Question 201

dominant wind direction Nile delta

Answer 201

from West/North-West 55-60% of the time

Question 202

coastal processes leading to Nile delta morphology

Answer 202

low-energy environment->deposition prevailing wind direction not perp. to coast LSD reworks sediment eastwards, creating spits which eventually become bars, behind which lagoons form coastal processes+ deposition= traditionally delta has grown & extended out into the Med lagoons have gradually been getting filled by sediment (no longer reworked by LSD)

Question 203

causes of future change to Nile delta landscape?

Answer 203

building of Azwan high dam consistent wave & wind energy climate change

Question 204

when was the Azwan Dam built?

Answer 204

1964

Question 205

purpose of Azwan Dam?

Answer 205

to ensure a water supply for the growing population of Egypt produce HEP

Question 206

effect of Azwan Dam construction on coastal system particular areas?

Answer 206

massively reduced water and sediment supply downstream virtually no sediment flows delta erodes/retreats by up to 148m/year areas most affected=by mouths of distributaries due to lack of sediment supply however E end of bars still growing due to LSD Rosetta Mouth eroded at 24m/year Damietta Mouth eroded at 36m/year

Question 207

effect of Azwan Dam construction on environment and population?

Answer 207

degraded agricultural land bc soils are less rich/fertile due to decreased flooding forces movement of people from farming to fishing in lagoons-> pressure exerted on fragile ecosystems if bars protecting lagoons are eroded, ecosystems will be lost along with the fish farming and economic potential (unsustainable approach bc landforms will be fully eroded in time)

Question 208

future issues of dam construction in Ethiopia for Nile delta

Answer 208

Ethiopia planning construction of large dam to store water for its industry, HEP and growing pop. political issues as this would inhibit sediment and water supply even further

Question 209

future nile delta landscape changes caused by consistent wind & wave energy

Answer 209

dom. winds (NW in summer and NE in winter) so sediment steadily reworked by LSD to increase size of onshore bars and spits seasonal wind direction difference will cancel out some of the LSD wind energy also moves sand from Burullus sand bar landward, decreasing size of lagoon

Question 210

future nile delta landscape change due to development on coast

Answer 210

drying of sand caused and more people to dunes bc vegetation which holds dunes together removed wind able to erode dunes more easily

Question 211

future changes of Nile delta due to climate change

Answer 211

sea level rise expected to be between 18 and 64cm by 2100 increased risk of flooding and delta inundated with saltwater, leading to in-farmable land->economic impact up to 60% loss of farmland by 2100 rate of coastal retreat will increase, reducing land available for human activity

Question 212

future changes of Nile delta due to climate change

Answer 212

sea level rise expected to be between 45 and 90cm by 2100 increased risk of flooding and delta inundated with saltwater, leading to in-farmable land->economic impact up to 60% loss of farmland by 2100 rate of coastal retreat will increase, reducing land available for human activity drinking water supplies and aquifers threatened breaching of bars and spits (especially at W end)->lagoons exposed to seawater GRADUAL change

Question 213

how have Damietta spit and Rosetta onshore bar formed?

Answer 213

sediment carried by distributor is deposited at mouth due to flocculation due to low-energy environment(short fetch and lack of tidal range), sediment accumulates prevailing wind direction is NW 55-60% of times so sediment is reworked East by LSD, forming a spit, which grows until it extends to reach the coast and forms a bar, trapping a lagoon behind it of brackish water

Question 214

how will Damietta spit and Rosetta onshore bar change over time?

Answer 214

Aswan Dam has decreased sediment supply so Damietta mouth erodes at 36m/year and Rosetta mouth at 24m/year (short term change, significant) E ends still growing steadily due to LSD/migrating SE (consistent wave/wind direction and energy) bar may be breached due to sea level rise caused by climate change in W end wave refraction recurves spit due to wave energy in deeper water smaller due to no new sediment

Question 215

Manzala and Burullus Lagoon formation

Answer 215

spit extends to meet coast due to LSD, trapping sea behind it (encloses bay), forming a bar and lagoon of brackish water

Question 216

Manzala and Burullus Lagoon future change

Answer 216

being drained for farming so drying out agricultural waste filling it up is decreasing lagoon size wind energy moving sand into lagoon form bar= decreased size people forced to move form arable farming to fishing= pressure on fragile ecosystems bars eroded/breached due to lack of sediment supply and sea level rise, so no more shelter for lagoons and they are exposed to seawater

Question 217

Gamsa sand dunes formation

Answer 217

result form large back shore area onshore winds allow for aeolian processes (saltation, deposition) to take place warm, dry conditions and thermal energy dry sand out, making it easier for the wind to transport

Question 218

size and location of Gamsa sand dunes

Answer 218

30km across between the 2 lagoons

Question 219

future change of Gamsa sand dunes

Answer 219

dunes migrate and move South with wind highway developed along coast so more people to area, meaning vegetation holding dunes together is eroded more easily CC=warmer so drier sand, which is eroded more easily decreased sediment supply means eroded sediment is less likely to be replaces

Question 220

formation of crescentic bars at Alexandria

Answer 220

formed by rip currents and onshore water with little LSD

Question 221

Sabkahs (salt flats) formation

Answer 221

have formed behind Manzala and Burullus lagoons, where older lagoons have dried out leaving flat salt plains water evaporates, minerals concentrate until only salt remains

Question 222

future change of Sabkahs

Answer 222

climate change= increased temps= increased evaporation of water in lagoons so increased Sabah formation lagoon drained for farming so more sabkahs form

Question 223

physical factors affecting nile delta landscape

Answer 223

wave energy wind energy sediment supply

Question 224

how does wave energy affect landscape Nile delta specific landforms due to this?

Answer 224

prevailing wind direction = NW so LSD creates spits/bars and drift aligned beaches bc sediment is transported along coast waves are low energy/constructive and have small tidal range so deposition is more dominant so there is less erosion-> depositional landforms

Question 225

how significant is wave energy in affecting the Nile Delta landscape?

Answer 225

varies seasonally (NW summer, NE winter) so may reverse effects, but 55-60% from NW sig. in transporting seidment requires constant input of sediment slow/long term change

Question 226

how does wind energy affect landscape in Nile delta? specific landforms affected?

Answer 226

powers wave direction and LSD forms sand dunes through aeolian processes short fetch in Med so decreased wind energy dom. wind direction =W->E in summer fairly consistent strength sand dunes affected (saltation, transportation) LSD: spits/bars by determing wave direction

Question 227

how significant is wind energy in affecting the Nile Delta landscape?

Answer 227

similar to waves (controls them) varies seasonally (NW summer, NE winter) and diurnally forms sand dunes but relies on big beaches/ sediment supply being continuous

Question 228

how does sediment supply affect landscape in Nile delta? specific landforms affected?

Answer 228

HISTORICALLY provided 120million tonnes of sediment for formation of spits/bars/dunes through LSD/aeolian processes sediment inputted to system positive sediment budget PRESENT azwan dam, 1964 so virtually 0 sediment input to system from river delta eroding/retreating by up to 148m/year

Question 229

how significant is sediment supply in affecting the Nile Delta landscape?

Answer 229

rising sea levels and decreasing sediment supply due to Aswan dam means coastline retretaing and flooding, bars breaching e.t.c. used to be v. sig providing sediment for depositional landforms

Question 230

how are Damietta spit and rosetta bar interrelated?

Answer 230

rosetta bar affects Damietta spit bc LSD reworks sediment from the bar eastwards to the spit

Question 231

eustatic change definition

Answer 231

global change in sea level

Question 232

isostatic change definition

Answer 232

regional change in land level

Question 233

describe eustatic change

Answer 233

last 18000 years= interglacial (gone from glacial to warm period) 120m s.l rise on average so submerging landforms caused massive input of sediment 'rolled onshore' by rising sea levels (flandrian transgression) last 6000 years= stable temps & climate, which allowed progression of civilisation

Question 234

describe isostatic change

Answer 234

happens due to glaciers melting & land 'rebounding' back up or due to tectonic activity e.g. in Scotland and Scandinavia areas with large isostatic change= less worried about sea level rise flooding them bc isostatic changes are not caught up by eustatic change

Question 235

examples of submergent landforms

Answer 235

rias fjords shingle beach

Question 236

examples of emergent landforms

Answer 236

relict cliff marine terrace raised beach

Question 237

briefly, what is a fjord?

Answer 237

a submerged glacial valley with steep, cliff-like valley sides

Question 238

characteristics of fjords

Answer 238

uniformly deep water (often over 1000m) not very wide (2-4km) U-shaped cross section (reflects shape of original glacial valley) threshold at the end of the valley is the shallowest part straighter than rias steep, cliff-like valley sides

Question 239

over what period of time did fjords form?

Answer 239

last ice age wouldn't have solely caused the formation of fjords/formed over last hundreds of thousands of years

Question 240

describe the formation of fjords

Answer 240

originally, valleys were secured by glaciers through plucking and abrasion, creating up to 3km deep U-shaped valleys glaciers melted in last warm period, increasing sea level and flooding glacial valleys glacial valleys are narrow, deep, 2km high and steep sided have threshold at end near mouth where glacier didn't erode and deposited terminal moraines cruise ships and submarines easily frequent

Question 241

what are lochs and when do they form?

Answer 241

when glaciers melt and sea level rises, flooding glacial valley if valley is only partially flooded and not joined to the sea it is called a loch (e.g. in Scotland)

Question 242

examples of fjords

Answer 242

Sognefjord in Norway Milford Sound in New Zealand

Question 243

current geomorphic processes acting on fjords?

Answer 243

coastal erosion at sea level, very slowly widening the fjord (v. slow bc rock type is usually hard so this is insignificant). notches may form. eustatic s.l. rise deepens the fjord freeze-thaw and biological weathering cause the steep sides to become less steep as material is weathered away (scree) mass movement events: steep valley sides are prone to rock fall after weathering/heavy rainfall

Question 244

characteristics of fjord on a map

Answer 244

straight path steep valley sides not very wide

Question 245

briefly, what is a ria?

Answer 245

a funnel shaped estuary that occurs at a river mouth. formed by submergence of lower portion of river valley. flooded river valley.

Question 246

describe the formation of a ria

Answer 246

throughout lowland coastal areas, rivers form floodplains and deltas= flat and wide, made of weak alluvial deposits (silts, clays deposited due to flocculation) when sea level rises, these floodplains get flooded, creating bodies of water which are wide but shallow, with one deeper section where the river used to be often have multiple tributaries which were river tributaries which have all flooded. common on south coast of UK, and due to large tidal range theyb often leas to inlets which are only navigable by boats at high tide: creates large mud flats whihc are good for wildlife (e.g. wading birds)

Question 247

current geomorphic processes affecting rias?

Answer 247

coastal erosion processes at sea level at the mouth can form notches rivers depositing at the river mouth due to flocculation of river sediments silt up the ria and fill it in sea level rise due to climate change (continuing eustatic change) will deepen ria (better for shipping)

Question 248

why are human settlements often found in rias? what impacts can humans have on rias?

Answer 248

sheltered coastal locations may dredge the areas for shipping, develop sea defences to alter the processes to protect human settlements

Question 249

why do rias cause an exaggerated tidal effect?

Answer 249

they have a widening funnel shape which steadily increase in depth

Question 250

when did rias form?

Answer 250

during interglacial period last 18000 years

Question 251

rias cross section

Answer 251

V-shaped

Question 252

example of rias

Answer 252

Kingsbridge Estuary on South Devon coast 6 miles long 1 mile wide near mouth a Salcombe 2 large drowned tributaires extend form east side of ria

Question 253

briefly, what is a shingle beach?

Answer 253

long beaches with a large quantity of sediment (glacial in origin) which is greater than would have been provided from cliff erosion material found on beach= between 2 and 200mm and often rounded

Question 254

source of sediment for shingle beach

Answer 254

sediment would have been rolled up from offshore as sea levels rose during the Flandrian Transgression, hence causing wave action to to push the sediment onshore sediment was originally deposited by glaciers or form periglacial processes during glacial periods

Question 255

example of shingle beach

Answer 255

Chesil Beach, Dorset 29km long constructive waves have moved it inland has formed a tombolo, connecting the Isle of Purbeck to the mainland, and a lagoon behind it called the Fleet has formed barrier shingle beach no longer growing bc all of sediment transported from offshore, leaving beach as a relict feature LSD re-works sediment south east

Question 256

effects of current geomorphic processes on shingle beaches

Answer 256

LSD can rework sediments, creating a beach with an asymmetric profile or sediment that is more rounded at one end than another constructive waves creating larger beaches destructive waves removing sediment

Question 257

human action impacts on shingle beach?

Answer 257

groynes slow sediment transfer due to LSD

Question 258

8 MARKER HOW HAVE SEA LEVEL RISE AND CURRENT GEOMORPHIC PROCESSES INFLUENCED FORMATION OF SHINGLE BEACHES

Answer 258

single beaches= large beaches w/ large quantity of sediment which is greater than could have been provided by cliff erosion. 'shingle':2-200mm rounded sediment eustatic change is responsible. initially, s.l falls due to fall in global temp so glaciers advance. in most recent interglacial, glaciers retreated and deposited outwash plains containing lots of reworked glacial sediment. 10000 to 6000 y ago, Flandrian Transgressiom reworked this sediment onshore by constructive wave action w/ s.l rise to form shingle beaches CHESIL BEACH EXAMPLE in future, eustatic rise due to CC may flood single beaches through higher/stronger destructive waves eroding them. current geomorphic processes= LSD: reworking sediment to create asymmetric profile or beach w/ more angular sediment at one end or can recurve spit to form barrier beach/tombolo constructive waves can build up beach w/ material eroded from cliffs/fluvial inputs. human interventions can alter impacts e.g. groynes NO LONGER REPLENISHED BC RELICT INPUT SO NEGATIVE SEDIMENT BUDGET

Question 259

how to answer 8 marker of emergent/submergent landforms

Answer 259

describe it draw a diagram role of eustatic change: explain this role of current geomorphic processes: coastal, weathering, continuing eustatic change, rivers depositing,

Question 260

what are drowned forest?

Answer 260

after glaciers retreated, vegetation and forests pioneered the glacial outwash and boulders clay left behind. however, as sea levels subsequently rose, these forests were drowned by the sea

Question 261

examples of drowned forests

Answer 261

bexhill in East Sussex

Question 262

why are emergent landforms forming?

Answer 262

isostatic rebound (land level rising): previous glaciers pushed down/compressed land. when the glaciers melted, the land rebounded (about 15,000 years ago) historical eustatic change (sea level falling)

Question 263

where are emergent landforms forming?

Answer 263

Scotland, NW UK, California, Scandinavia

Question 264

effects of current geomorphic processes on relict cliffs

Answer 264

biological weathering loosening material @ top so leading to mass movement events, decreasing steepness of the cliffs current eustatic change leads to cliff becoming active/drowned

Question 265

effects of geomorphic processes on raised beach

Answer 265

biological weathering and colonisation by vegetation current eustatic change leads to beach becoming active

Question 266

how are marine terraces different to raised beaches?

Answer 266

(used to be shore platform) STEPPED: 2 periods of isostatic/eustatic change

Question 267

case study of a coastal landscape that is being managed intentionally?

Answer 267

West Somerset Coastline: Minehead

Question 268

what does 'intentional' mean in terms of activity on a coastline?

Answer 268

planned, deliberate action taken in order to protect it e.g. from floods, erosion, coastal retreat, mass movement, threshold events

Question 269

what is the shoreline management plan?

Answer 269

sustainable strategy for flood and coastal defences how to manage entire coastline, recognising budgeting limitations

Question 270

management strategy at Porlock Bay justification

Answer 270

Managed realignment in short and long term low-value land, low-pop. density, so there are less negative consequences removes pressure off Minehead

Question 271

management strategy at seaworthy cliffs justification

Answer 271

do nothing resistant rock type (quartzite) so a were erosion rate. decreased likelihood of retreat and provides own defence low population density

Question 272

management strategy at minehead justification

Answer 272

hold the line by maintaining and improving defences high-value land and high pop. density mudstones in the bay= less resistant rock type so is more prone to erosion and retreat. therefore it requires human intervention to protect the land behind

Question 273

management strategy at the warren golf course justification

Answer 273

ST: protection, hold the line. LT: managed realignment as protection becomes unsustainable lower value land so will be sacrificed as sea level rises next to Minehead (so is currently worth protecting)

Question 274

reasons to protect Minehead?

Answer 274

high population density and high value land low-lying (around 7m) socio-economic profile of minehead relies on butlins, where the beach is the key attraction. therefore the coastal protection increases tourism, causing PME, tourists bring money to Minehead and creates lots of jobs.

Question 275

how has butlins decreased seaosonality of tourism?

Answer 275

popular all year round due to xmas themes, stag/hen dos

Question 276

advantages of using OS maps

Answer 276

has scale: can compare distances and measure land use and land height are clearly displayed spatially and proportionally accurate features easy to read 'layers' of information physical geo and human land use

Question 277

disadvantages of using OS maps

Answer 277

no temporal change: displays an area in an instant: 'snapshot' so could be outdated over time doesn't show seasonal variation in beach e.g. height and width

Question 278

advantages of using aerial photos

Answer 278

visually east to see land use (physical and human) easy to understand/access easy to do re-photography

Question 279

disadvantages of using aerial photos

Answer 279

doesn't show scale, height (contours), tidal change lack of labels/information: cannot necessarily tell what they are no compass points

Question 280

coastal processes at Minehead coast

Answer 280

sediment eroded form cliffs at seaworthy= SMALL input LSD inputs sediment from West historic inputs of sediment due to sea level rise 6000 years ago flow of LSD and constructive waves transporting sediments output of LSD and destructive waves, especially during a strom

Question 281

description of curved sea wall

Answer 281

deflects waves and reduces overtopping recurved face rotates the wave backwards so that some of the energy is reflected back at sea, which impedes the next wave reducing its energy, and thus its erosive power. nature of all prevents all but extreme coastal flooding

Question 282

how do curved sea walls impact the system/ processes/ landforms at mine head?

Answer 282

has curved front to deflect waves and reduces overtopping. reflects wave energy back out to sea. BUT increases strength of backwash so erodes beach (waves won't break in front of it so is less effective) shouldn't be sued alone landward side faced with attractive local red sandstone, increasing visual amenity although ti was expensive, it is effective at decreasing erosion wide walkway with seating so popular with toursits

Question 283

how high is mine heads curved sea wall?

Answer 283

0.6m

Question 284

how do rock groynes impact the system/processes /landforms at mine head

Answer 284

work with physical flow: interlink of human and physical traps sediment being moved bay LSD (flow) to build up beach (store): absorbs wave energy and decreases flood risk in mine head. has caused beach to grow up to 80m in width, increasing tourism and providing shelter from wind too good for fishing terminal groyne to E starves area in front of golf course of sediment, increasing rate of erosion and vulnerability to floods. in the next 50-100 years, predictions of up to 100m in coastal retreat

Question 285

what does rip-rap do? how does rip-rap impact the system/ processes/ landforms?

Answer 285

at base of sea-wall to dissipate some of the wave energy, so decreases flood risk and rate of erosion expensive but low maintenance and cost of upkeep rocs chosen blend in with local landscape, increasing visual amenity can have short lifespan but effective at preventing erosion fishing and wildlife can benefit bc habitats are created

Question 286

beach nourishment impacts on system/ processes/ landforms

Answer 286

sand used to build up beach by 2m in height, forcing waves to break further outs to sea, decreasing energy focused on sea wall sandy beach formed for tourists, increasing tourism (which is vital for mineheads econ. profile) medium capital costs and maintenance costs bc it is eroded so must be replaced annually (not v. sustainable)

Question 287

what is the best form of coastal defence?

Answer 287

beach: natural defence absorbs wave energy so decreases energy reaching the sea wall less likelihood of erosion of hard engineering strategies, so less cost of upkeep easier and cheaper to replace than hard engineering

Question 288

positive or negative sediment budget at mine head? why?

Answer 288

due to hard engineering, there is a negative sediment budget most sediment on the beach is relict from the last sea level rise (there are a few inputs e.g. cliff erosion, LSD but these are small) cliffs to W= hard rock so have little erosion sea wall increases strength of backwash and therefore increases outputs, especially during storms

Question 289

why will managed retreat strategy be adopted at golf course in the future?

Answer 289

increased risk for flooding is significant retreat of 110m in next 50 years low-value land

Question 290

what is the concern with allowing managed retreat at the golf course?

Answer 290

flanking (sea eroding and flooding the unprotected east and then flooding into mine head)

Question 291

scale of natural/human factors influencing coastline at mine head?

Answer 291

human= small scale, varies place to place, only small area is protected natural= large scale: sea level rise=global, LSD=fairly large scale but varies slightly dependent on angle of becah or wind direction

Question 292

timeframe of natural vs human factors influencing coastline at minehead?

Answer 292

human= short term: due to costal retreat, s,l rise, must be replaced natural= long term s.l rise and sediment inputs. minimised impacts in short term by human activity

Question 293

natural vs human factors influencing coastline in LIDC vs AC

Answer 293

ACs can afford coastal protection schemes more readily therefore natural factors impact coastlines in LIDCs more in short AND long term and on small AND large scale

Question 294

case study of unintentional impact of coastal management?

Answer 294

mangawahi-pakiri coast, new zealand

Question 295

historical background of pakiri sand mining

Answer 295

on 8 Feb 1994, the minister of conservation granted commercial sand extractors five coastal permits under the RMS to dredge sand from the nearshore seabed at Mangawhai and Pakiri. the permits allow a total of up to 165,000m3 of sand to be won annually for 10 years

Question 296

why is sand being mined at Pakiri/

Answer 296

sand fro glass, fill, concrete/bricks, beach nourishment

Question 297

beach nourishment using sand form pakir?

Answer 297

sand from pakiri used to re nourish ailing beaches , esp. in popular places where the cost can be justified economically by visitors. e.g. in Auckland

Question 298

cost of 1m3 of sand in NZ

Answer 298

$40 in 2000

Question 299

why is the sand being mined for glass/concrete/bricks?

Answer 299

construction of buildings in Auckland

Question 300

how much sand is mined weekly in pakiri?

Answer 300

1500 tonnes

Question 301

how does pakiri's location make it attractive for sand mining?

Answer 301

high-quality sand resource occurs in the nearshore zone here sand is suitable for construction industry 5km north of Auckland: NZ's largest region, which is home to 1/3 of its population and is growing rapidly. therefore, demand for sand for construction is growing

Question 302

overview of past/current sand mining in pakiri

Answer 302

nearshore sand dredging on the coastline has operated for over 70 years between 1994 and 2004, 165000m3/year mining ended at mangawhai in 2005, but has continued at pakiri current rates= 75000m3/year until 2020

Question 303

here was sediment at pakiri beach originally sourced from?

Answer 303

deposited during Holocene (past 9000 years) sand=non-renewable resource on this coastline few sizeable rivers in the area and most sand is derived from offshore

Question 304

what sort of landform is pakiri beach?

Answer 304

shingle beach emergent landform

Question 305

sediment budget and system at pakiri beach?

Answer 305

CLOSED SYSTEM outputs of sand through nearshore mining are not replaced by current inputs NEGATIVES SEDIMENT BUDGET

Question 306

ratio of inputs to outputs at pakiri beach?

Answer 306

1:5

Question 307

what impacts is the mining having on the coastal landforms at pakiri?

Answer 307

beach starve dog sediment so is narrowe and flatter, less effective at absorbing wave energy increased wave energy erodes the beaches, so dunes and spits are more vulnerable foredune ridges are undercut by wave action to form steep, seaward-facing scarps (cliffs) loss of vegetation make the dunes susceptible to wind erosion

Question 308

impacts of storm at pakiri in 1978? what did humans do in response?

Answer 308

28m breach 2 base of mangawhai spit & a 2nd breach altered tidal currents, causing sedimentation of mangawhai's harbour therefore, water in the harbour was made shallower, and the waterfront community was threatened by flooding the harbour was therefore dredged and groynes were constructed on the spit, restoring some equilibrium

Question 309

statistics for coastal retreat in future at pakiri

Answer 309

LT retreat by 2100 is estimated at 35m width of coastal zone susceptible to erosion varies from 48 to 11m (higher than any of the Auckland region's other 123 beaches)

Question 310

why are rates of coastal erosion going to retreat in the future at pakirir?

Answer 310

Auckland regional council studies suggest increased rates of erosion with decreased natural protection from extreme storm events costal retreat is attributed partly to sand extraction, though this is complicated by climate change and sea level rise

Question 311

dredging at pakiri depth?

Answer 311

occurring at 8-10m depth= active sediment form here is usually moved by constructive waves onto the beach. THEREFORE sediment budget= negative IF sediment was taken from deeper (18-25m), it wouldn't impact the coastal system bc waves are not breaking here so this sediment is not being used to replenish the beach

Question 312

which area of pakiri will lose sediment first` `why?

Answer 312

the southern end due to LSD reworking sediment north

Question 313

impacts of manmade pine forest on pakiri beach system?

Answer 313

as the trees grow, they lift the sea wind off the beach, impairing the beach's self repair mechanism with the sea wind reduced, the beach sand would not dry as quickly and once dried, would nnot eb blown into the dunes. lakc of sand reaching the beach means sand dunes are starved of a key source of sediment, so are becoming lower and narrower, reducing the resilience of the coastline to flooding. dunes are in process of retreat, leaving steep banks behind

Question 314

local conservation society fighting for the end of sand mining?

Answer 314

successfully fought to stop it off the spit in 2004 BUT dredges still operate to the south off pakiri: starving sediment supply and spit is in precarious situation. will have greater consequences on sediment budget and tourism in area

Question 315

future concern for pakiri?

Answer 315

at some point, a large, infrequent winter storm will cause a breach significant enough to permanently change the morphology of the landscape and create a new equilibrium state

Question 316

how could New Zealand government reduce future concern for pakiri beach?

Answer 316

confine sand mining to a depth where sediment is not being moved within the surf zone

Question 317

to what extent do unintentional impacts influence coastal landforms and processes?

Answer 317

human actions make coastal system less resilient to natural processes so the physical factors have increased risk the equilibrium was disturbed by human action, creating a negative sediemnt budget

Question 318

points to make in question: to whaty extent are long term changes mire influential on coastal landscape systems than short term changes? SHORT TERM PARA

Answer 318

ST: e.g. of flamborough case study. take place over seconds mass movements drastically change shape: difficult to adapt to/predict: social impacts e.g. Holbeck Hall Hotel. inputs of sediment so provide material for dep. landforms. cliff collapse in heavily-jointed rocks. many of these ST slowly form shore platform over LT happen infrequently e.g. collapse of arch to stack. SMALL SCALE, harder rock. add sediment to system, contributing to LT changes to shape human management impacts flows of energy & sediment e.g. Azwan Dam. will have LT impacts of coastal retreat. breaching can occur due to groynes, flooding homes or ecosystems (porlock) threshold events, irreversible change to new state. move away form equilibrium SMALLER SCALE SO SEEN AS LESS INFLUENTIAL SHORTER TIME PERIODS STEPPING STONES TO LT CHANGE

Question 319

points to make in question: to whaty extent are long term changes mire influential on coastal landscape systems than short term changes? LONG TERM PARA

Answer 319

take places over 100,000s of years: gradual and long-lasting sea level rise due to climate change= GLOBAL SCALE. continuous impact. causes ST events, e.g. bar breaching. historic inputs of sediment: Flandrian= used for formation of dep. landforms e.g. tombolos. CC also causing floods e.g. Nile Delta retreat warming ocean temps & acidification change ocean currents and sediment supply, erosion by solution changes to rainfall affect weathering of cliff tops, and more extreme weather will increase chance of ST mass movement events. dev. of beach/spit/bar= built up by constructive waves ST cliff collapses cause formation of shore platforms= negative feedbakc loop HUGE SOCIAL IMPACTS OF FLOODS GOBALLY large spatial impacts impacts size/shape of coastline, so impact potential for dev. and land use. harder to protect against/adapt to due to ongoing nature: challenge for LIDCs

Question 320

points to make in question: to whaty extent are long term changes mire influential on coastal landscape systems than short term changes? CONCLUSION

Answer 320

LT more sig. in low energy coastline dependence between LT and ST changes: complex interrelationship global scale and future impacts presented by CC which is accelerated by human action will present socioeconomic challenges, esp. in LIDCs change position and shape of coastal profiles, affecting where wave energy hits and where ST changes happen