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gcse geography > changing landscapes/coasts > Flashcards

changing landscapes/coasts Flashcards

1
Q

how is igneous rock formed and what are the characteristics

A

when molten rock (magma) from the mantle cools down and hardens, rock forms crystals as it cools
- usually hard e.g granite and basalt

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2
Q

how is sedimentary rock formed and what are the characteristics

A

layers of sediment are compacted together until they become solid rock
- usually softer and easily eroded but some are relatively hard
- e.g sandstone, chalk

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3
Q

how is metamorphic rock formed and what are the characteristics

A

when other rocks are changed by heat and pressure and the new rocks broken harder and more compact
e.g clay -> slate + more pressure n heat -> schist

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4
Q

how have active volcanoes shaped the landscape of the uk?

A

volcanic eruptions formed through earth’s crust which cooled to form igneous rocks e.g granite and basalt

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5
Q

how have plate collisions volcanoes shaped the landscape of the uk?

A
  • collisions between tectonic played caused the rocks to be folded and uplifted forming mountain ranges with some areas remaining as uplands (scottish highlands e.g)
  • intense heat n pressure caused by pc formed hard metamorphic rocks in N scotland
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6
Q

how have active plate movemos shaped the landscape of the uk?

A
  • carboniferous limestone formed in warm shallow seas (seen in uplands of peak district in N england + S wales
  • chalks n clays formed in shallow seas and swaps and form lowland landscapes
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7
Q

what are the characteristics of granite

A
  • igneous + forms upland landscapes
  • lots of joints (not evenly spread) (areas w more joints wear down faster, areas w less = weathered slowly)
  • impermeable - doesn’t let water through, creating moorlands, w low growing vegetation
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8
Q

what are the characteristics of basalt?

A
  • igneous + made of volcanic lava
  • v hard + impermeable, forms escapements in uplands n cliffs at coasts
  • as lava cools it forms columns
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9
Q

what are the characteristics of chalk?

A
  • sedimentary, forms hills in lowlands + cliffs at coast
  • chalk is permeable, water flows through it n emerges as a spring where it meets impermeable rock
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10
Q

what are the characteristics of sandstone?

A
  • sedimentary, made from sand
  • softer stand stones form lowland landscapes
  • harder sandstones form upland landscapes
  • porous, has small gaps so it can store water in underground aquifers
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11
Q

what are the characteristics of late and schist?

A
  • metamorphic rocks
  • slate: forms in layers creating weak planes in rock, hard + resistant to weathering but easily split into thin slabs
  • schist has bigger crystals and splits easily into small flakes
  • both form rugged upland landscapes, impermeable which lead to waterlogged and acidic soils
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12
Q

how was the landscape also shaped by ice?

A
  • during last glacial period ice covered uk, able to erode landscape + carved out u-shaped valleys in upland areas (e.g lake district)
  • glaciation affected lowland areas, it deposited material as it melted
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13
Q

what physical processes alter the landscape?

A
  • weathering
  • erosion
  • post-glacial river processes
  • slope processes
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14
Q

how have physical processes interacted to create upland areas (snowdonia) ?

A
  • freeze-thaw w occurs on back wall of corrie n as rocks are broken up, there are rock falls, forming scree slopes
  • lots of rain + impermeable rocks + lots of strreams eroding sides of corrie and forming gullies
  • llyn idwal sits in a corrie that was hollowed out in glacial times
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15
Q

how have physical processes interacted to create lowland areas (the downs and the weald)

A

large rivers meander on impermeable clay, widening valley floor
- uk + wet climate, leads to flooding, n overflowing river deposits silt onto valley floor forming a flood plain

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16
Q

how have humans changed the landscape through agriculture?

A
  • cleared forest to make space for farming, hedgerows and walls built to mark out fields
  • landscapes adapted for different types of farming
    -> arable (growing crops, flat land good soil)
    -> dairy (warm wet areas, grassy fields)
    -> sheep (led to lack of trees as they vare eaten or trampled on before maturing)
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17
Q

how have humans changed the landscapes through forestry?

A

forestry = management of areas of woodlands, used for timber recreation or conservation
little deciduous woodland left, coniferous forests planted for timber
- c trees planted in straight lines, when area is felled, landscape left bare affecting drainage and lead to increased erosion

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18
Q

how have humans changed the landscapes through settlement?

A
  • land concreted over for roads and buildings, affecting drainage patterns
  • rivers diverted through underground channels
  • river channels straightened or embankments built to prevent flooding
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19
Q

how is rock broken down by mechanical weathering?

A

mechanical w - breakdown of rock w/o changing comp comp
- salt weathering: 1. seawater gets into cracks into rock
2. water evaporates, salt crystals form, expands and puts pressure on the rock
3. repeated evaporation and forming of salt crystals widens crack and causes the rock to break up

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20
Q

how is rock broken up by chemical weathering?

A

cw - breakdown of rock by changing its comp.
- 1. rainwater has CO2 dissolved in it + weak carbonic acid
2. carbonic acid reacts w rock that contains calcium carbonate e.g chalk, so rock dissolves

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21
Q

how is rock broken up by biological weathering?

A

bio w - breakdown of rock by living things
- animals e.g rabbits burrow into soil on cliff tops
- plant roots breakdown rocks by growing into cracks on their surfaces and pushing them apart

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22
Q

what is mass movement?

A

the shifting of rocks and loose material down a slope and happens when the force of gravoty acting on a slope is greater than the force supporting it
- cause coasts to retreat rapidly

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23
Q

what are the 4 processes of erosion?

A

hydraulic action - (waves crash against rock + compress air in cracks, putting pressure on rock, repeated compression widens crack making bits of rocks break off)
abrasion - (eroded particles in water scrape n rub against rock removing small pieces)
- attrition (eroded particles smash into each other, rounding the edges and breaking into smaller fragments)
- solution (dissolves CO2 makes water slightly acidic, acid reacts w rocks n dissolved them)

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24
Q

what are the characteristics of destructive waves?

A

high frequency (10-14 wpm)
high + steep
backwash (movement down beach) is more powerful than swash (movement up beach) -> material is removed from coast

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25
Q

what are the characteristics of constructive waves?

A

low frequency (6-8 wpm)
low + long
swash is powerful, carries mats. up coast
backwash is weaker -> mats. deposited on coast

26
Q

describe the process of longshore drift

A
  1. waves follow process of prevailing wind and hit the coast at an oblique angle
  2. swash carries material up the beach in the same direction of the waves
  3. backwash carries it back down the beach at right angles, back towards the sea
  4. overtime mats. zigzag along coast
27
Q

what are the other 4 processes of transportation?

A

traction (large particles pushed along the seabed by force of water)
suspension (small particles carried along in water)
saltation (pebble-sized particles bounced along seabed by force of water)
solution (soluble mats. dissolve in water + carried along)

28
Q

what is deposition and when does it occur?

A

when material being carried by seawater is dropped on the coast, it occurs when water carrying sediment slows down so that it isn’t moving fast enough to carry so much sediment

29
Q
  1. why are beaches built up?
  2. the amount of material that’s deposited on the coast is increased when?
A
  1. beaches are built up when amount of deposition is greater than amount of erosion
    • lots of erosion + more materials available
      - lots of transportation
30
Q

what are the features of a discordant coastline?

A
  • made up of alternating bands of hard n soft rock at right angles to the coast
  • form headlands and bays as they erode at diff. rates (soft rocks erode faster than hard rock)
31
Q

what are the features of a concordant coastline?

A
  • made of alternating bands of hard n soft rock parallel to coast
  • eroded at same rate along the coast -> fewer erosional landforms
32
Q

how does weather have an impact on coastal erosion and retreat?

A
  • differences in temps have impact on processes along coast e.g mild temps increase rate of salt weathering as water evaporates quicker -> alters landscape e.g weathering loosens material n leads to mass movement
33
Q

how do storms have an impact on coastal erosion and retreat?

A

strong winds during storms create high energy destructive waves that increase erosion and cause coastal retreat
- intense rainfall cause cliffs to become saturated, making mass movement more likely

34
Q

how do prevailing winds have an impact on coastal erosion and retreat?

A
  • determines direction of LSD, affecting where deposition happens
  • affects whether a coastline is exposed to storms or sheltered from them -> more exposed coasts are more vulnerable to erosion and coastal retreat
35
Q

how are wave-cut platforms formed?

A
  1. waves cause most erosion at foot of the cliff between the high and low water mark, forming a wave cut notch, which enlarges as erosion ( HA + A) continues.
  2. As the notch increases in size, the cliff becomes unstable and collapses, leading to the retreat of the cliff face
  3. The backwash carries away the eroded material, leaving a wave-cut platform.
    The process repeats. The cliff continues to retreat.
36
Q

how are headlands and bays formed?

A

formed at discordant coastlines
- soft rock (lots of joints, low resistance to erosion) erodes quickly forming a bay (has gentle slope)
- resistant rock w less joints erodes slower and juts out, forming a headland (has steep sides)

37
Q

how are headlands eroded to form caves, arches, stacks and stumps?

A

1.Cracks are widened in the headland through the erosional processes of hydraulic action and abrasion.
2. after repeated erosion and enlargement of cracks, it begins to open up to form a cave.
3. continued erosion deepens cave until it breaks through headland forming an ARCH
4. The base of the arch continually becomes wider through further erosion, until its roof becomes too heavy and collapses into the sea. This leaves a stack
5.The stack is undercut at the base until it collapses to form a stump

38
Q

what are the characteristics of sand beaches?

A

flat + wide
sand particles are small and weak backwash can move them back down beach creating long gentle slope

39
Q

what are the characteristics of shingle beaches?

A

steep + narrow
shingle particles are large and the weak backwash cannot move them down the beach, instead it builds up and creates steep slope

40
Q

how does deposited sediment form spits?

A

A spit is an extended stretch of sand or shingle jutting out into the sea from the land (occur when there is a change in the shape of the landscape or there is a river mouth)
1,Sediment is carried by longshore drift.
2.When there is a change in the shape of the coastline, deposition occurs. A long thin ridge of material is deposited. This is the spit.
3.A hooked end can form if there is a change in wind direction.
4.Waves cannot get past a spit, therefore the water behind a spit is very sheltered. Silts are deposited here to form salt marshes or mud flats.

41
Q

how is a bar formed?

A

when a spit joins 2 headlands together
cuts off bay between headlands from sea, lagoon formed behind bar

42
Q

how does industry affect coastal landscapes?

A
  • coastal quarries expose big areas of rock + vulnerable to chem. w + erosion
  • gravel extracted from beach for construction, increased risk of erosion, less mats. to protect cliff
43
Q

how does urbanisation affect coastal landscapes?

A
  • coasts w lots of settlement have more coastal defences than others to protect homes, businesses -> land better protected against erosion
  • building on coastal lowlands restrict sediment supply to beaches, making them narrower -> doesn’t protect beach well, vulnerable to erosion
44
Q

how does agriculture affect coastal landscapes?

A
  • clearing vegetation to make room for crops can expose soil n underlying rock, vulnerable to weathering
  • marshland sometimes reclaimed and drained for agriculture use, reducing natural flood barrier marshland provides
45
Q

how does coastal retreat and flooding affect people?

A
  • homes + businesses in low-lying areas = vulnerable to flooding, coastal retreat means sea = closer to settlements -> less protected by beaches during storms n high tides increasing risks of flooding
  • flooding + erosion can put people off visiting, businesses that rely on tourism may close leading to a loss livelihoods
46
Q

how does coastal retreat and flooding affect the environment?

A
  • force of floodwater can uproot trees and plants, standing floodwater drowns plants
  • coastal flooding brings saltwater into freshwater ecosystems, increased salt levels in soil n water can damage or kill organisms and reduce soil fertility
47
Q

what is hard engineering?

A

man-made structures built to control the flow of the sea and reduce flooding and erosion

48
Q

what is a sea wall, and what are the benefits and costs?

A
  • wall made of hard material that reflects waves back to sea
    -B: prevents erosion of the coast, acts as a barrier to prevent flooding
    -C: creates strong backwash, erodes under wall, walls are v expensive to build + maintain
49
Q

what is a riprap, and what are the benefits and costs?

A
  • boulders piled up along coast in a line (acts as a sea wall, gaps let water through, absorbing wave energy)
  • B: by absorbing wave energy it reduces erosion and flooding, cheap defence
    -C: boulders can be moved around, need to be replaced
    can lower level of beach (prevents cliffs from being eroded, no new material to replenish beaches)
50
Q

what is a groyne, and what are the benefits and costs?

A

wooden/stone fences built at right angles, traps mats. transported by LSD helping to build up beaches
- B: create wider beaches, slows waves protecting land from erosion and flooding, cheap defence
- C: starve beaches of sand, makes them narrower -> doesn’t protect beaches well, more erosion

51
Q

what is soft engineering?

A

schemes set up using knowledge of the sea and it processes to reduce effects of flooding and erosion

52
Q

what is beach nourishment, and what are the benefits and costs?

A
  • sand + shingle from elsewhere is added to upper part of beaches
    b: creates wider beaches which slows waves, giving greater protection from erosion and flooding
    c: taking mats. from seabed can kill organisms, v expensive defence, has to be repeated
53
Q

what is managed retreat and what are the benefits and costs?

A
  • removing existing defence and allowing the land behind it to flood, land becomes marshland, protecting land behind it from erosion
    b: cheaper in long run as it doesn’t need maintaining, marshland provides new habitat for plants and animals
    c: saltwater can damage existing ecosytems
    choosing area to flood can cause conflicts e.g flooding farmland affects farmers livelihoods
54
Q

where is dorset coast?

A

south coast of England

55
Q

what is the geology of dorset coast?

A
  • has concordant coastline to west, discordant to west
    rocks eroded at diff rates forming coastal landforms e.g Lulworth cove
  • soft rocks easily eroded by HA + A, formed bays e.g swanage bay
56
Q

what is the climate of dorset coast?

A
  • warm, dry summers, mild wet winters
  • exposed to prevailing winds from SW, can bring storms to UK w destructive waves increasing erosion
  • rain makes cliffs vulnerable to carbonation weathering + soil n rocks become saturated w water, making mass movement more likely
57
Q

how is durdle door influenced by physical processes

A
  • an arch on limestone headband
  • HA + Ab + At open crack in headbad, became cave, became arch
58
Q

how is lulworth cove influenced by physical processes

A
  • small bay fromed after gap eroded in band of limestone
  • limestone cliffs vulnerable to mass movement, n small slides + slumps
59
Q

how is dorset coast influenced by tourism?

A
  • attracts large number of tourists, coastal footpaths are worn down when repeatedly walked on
  • vegetation along cliff may be trampled and worn away by repeated use of footpaths, exposing underlying soil and rock to weathering
60
Q

how is dorset coast affected by industry?

A

-quarrying takes place, removing limestone to use as a valuable building stone, however leaves the rock underneath vulnerable to weathering and erosion
- chesil beach had gravel removed for industry, and mats. were removed from beach faster than it could be replenished, damaging landform

61
Q

how is dorset coast affected by coastal management?

A
  • new timber groynes installed long swanage beach 2005, helped to stop loss of beach material, but also starved coasts of sediment, making them narrower
  • concrete sea walls along coast, prevents erosion but creates strong backwash and erodes under wall

gcse geography (2 decks)

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