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Geog Things > Ice On Land > Flashcards

Ice On Land Flashcards

1
Q

What is Accumulation

Ablation?

A

Inputs into the glacial budget (eg snowfall)

Outputs from the glacial budget (eg meltwater)

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2
Q

Where does accumulation/ablation respectively dominate

A 
Acc = top of glacier (highest point)
Abl = snout of glacier (ie front)
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3
Q

Differences betw ice cap and ice sheet

A

Both glaciers

Ice sheet = over 50,000 km ^2 eg Antarctica and Greenland

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4
Q

What does it mean when a glacier retreats

A

When the total volume of the glacier decreases

As a result the glacier does not extend as far down the valley as previously

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4
Q

Differences betw ice cap and ice sheet

A

Both glaciers

Ice sheet = over 50,000 km ^2 eg Antarctica and Greenland

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6
Q

Facts about athabasca

A

In Canada

Nowadays only advances by 300m and is over 1750m away from max extent of 1850

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7
Q

Man made impacts on glacial budget?

A

Anthropogenic climate chance since IR (1850)
Deforestation
Greenhouse gases from burning of fossil fuels in vehicles and factory
= greenhouse effect
As a result avg global temp has increased from 9.6 to 10.8
Evidence of glacial impact = athabasca

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8
Q

Long term impacts on glacial budget

A

Milankovitch cycle - influences length of seasons and amount of solar radiation received by the earth which thus influences amount of abl / Acc

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9
Q

What is the milankovitch cycle?

What does it involve?

A

Describes how the earth orbits the sun
Includes
the eccentricity (how round the earth is)
The obliquity (angle of earths orbital axis)
The precession of the earth (direction of axis)

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10
Q

facts about the last ice age

A

Pleistocene
1.8 million - 11500 years ago
4 major ice sheets covered the planet, eg the British Isles were covered

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11
Q

What is the interglacial period we’re in called? Facts?

A

Holocene period
2 ice sheets
Antartica = 14 mil km^2
Greenland = 1.7 mil km^2 (80% Greenland)

Ice caps found in mountainous areas where temps are lower
Eg Iceland and the European Alps

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12
Q

Temp change from IR to now

A

Avg temp in Alps was 9.6, now 10.8

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13
Q

Causes of anthropogenic climate change

A

Deforestation : carbon sink
CFCs use (burnt hole in atmosphere)
Greenhouse gases emitted from oil/petrol
Oceans warming cos of global warming = ice melts which emits carbon

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14
Q

What direction does the glacier move? Why?

A

glacier flows from the zone of Acc and moves down the slope towards the zone of abl
It is under the influence of gravity and internal deformation

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15
Q

What is internal deformation

A

When the weight of the ice deforms the ice crystals
This usually happens near the glacial bed as pressure there is highest.
This enables different layers of ice to slide over each other

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16
Q

What is basal sliding

A

Meltwater at the base of a glacier acts as a lubricant and the glacier consequently slides over the land

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17
Q

Diagram of basal sliding

A

Glacier
Meltwater acting as lubricant
Bedrock

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18
Q

What do glaciers move fast with?

A

Increasing slope
Increasing snowfall
Increasing meltwater at the base of glacier

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19
Q

How does freeze thaw weathering work

A
  1. As it rains precipitation falls into the cracks of rocks
  2. Overnight the temp goes sub zero
  3. The water in the cracks expand by 9-10% as it is turning into ice
  4. As water expands the cracks expand
    (This repeats itself a lot)
  5. Eventually this weakens the rock until it breaks
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20
Q

What is left from freeze thaw weathering

A

Scree

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21
Q

What is scree

A

Small, broken down pieces of rock

They are generally jagged

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22
Q

What is ablation?

A

The wearing away of rock surfaces of the valley floor by the grinding effect of rock fragments frozen into the glacier base

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23
Q

What does ablation leave?

A

Sandpaper analogy!
Smooth surface
Striatations

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24
Q

What are Striatations?

A

Often left by abrasion

Scratches in the floor caused by large rocks beneath the ice

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25
Q

What is till?

A

Boulder clay found within the glacier

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26
Q

What is plucking? Analogy?

A

When meltwater freezes it bonds glacier to rocky surface below, therefore when the glacier lives it plucks away any loose rocks leaving a jagged landscape

Rock fragments are dragged along the base of the glacier
Extracting loose teeth analogy

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27
Q

What processes do all glaciers do

A

Erode
Transport
Deposit material

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28
Q

What happens when a glacier goes down a valley

A

It’ll begin to melt due to rise in temp

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29
Q

What happens as a glacier melts?

Key terminology answer as wel

A

It can’t carry as much material so it deposits it

The load has exceeded the glaciers carrying capacity

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30
Q

What are morraines

A

Ridges of sediment

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31
Q

Terminal morraine?

A

Sediment found at the max advance of glacier
Deposited as ice melts
Most of the material will have been plucked and carried at the base of glacier

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32
Q

What is lateral morraine?

A

Sediment (normally frost shattered material) found At the valley sides
(It had been carried on the side of the glacier)

33
Q

Medial morraines

A

When two valley glaciers meet and merge the two lateral morraines form one big morraine which runs down the centre of the largest glacier

34
Q

Recessional morraine?

A

Before the terminal morraine

When the glacier stops for a sufficient time to produce morraine yet the glacier has not reached its furthest extent yet

35
Q

What is bulldozing

A

Pushing of deposited sediment at the snout of the glacier as it advances

36
Q

What is a corrie

A

Arm chair shaped hollow high up on a hillside often containing a tarn.
Has a steep back wall and a raised lip

37
Q

How do corries form

A

Snow collects in a hollow high up on a mountain
This snow compacts into ice, forming a corrie glacier
The ice moves under gravity due to basal sliding
Ice rotates to the rock lip (flows uphill) and this rotational slip gouges out a deeper hollow
Abrasion deepens the hollow
Plucking steepens the back meal
A tarn may fill a hollow when ice has melted because of raised lip which forms due to reduced erosion at front of corrie because it’s thinner ice

38
Q

What is an arête?

A

A knife edged ridge, often formed betw two corries

39
Q

How do aretes form?

A

Occur when two neighbouring corries run back to back

As each erode each side of the ridge, the ridge becomes steeper and narrower

40
Q

What is a pyramidal peak?

A

Sharp edged mountain peak eg Mount Everest

41
Q

How do pyramidal peaks form?

A

If 3 or more corries hVe formed on a mountain all back to back erosion may cause it to become a single peak rather than a ridge

42
Q

Example of arête and pyramidal peak?

A

Arête - striding edge in Lake District

Pyramidal peak - Matterhorn, Mount Everest

43
Q

How are truncated Spurs formed?

A

When a glacier erodes through a valley where there used to be interlocking Spurs
The glacier can’t flow through the interlocking Spurs so it cuts through them
This leads steep edge Spurs at the sides of a glacial trough

44
Q

What are truncated Spurs

A

Steep edged Spurs at the side of a glacial trough

45
Q

What is a glacial trough

A

U shaped valley (used to be v shaped)

46
Q

What does it mean when a glacier advances

A

When the total volume of the glacier increases

As a result it will extend down the valley further than previously

47
Q

Formation of glacial trough?

A

There is a vshape valley with a main river running down it
In a period of glaciation the river freezes into main glacier
As the glacier lives down the valley it plucks and abrades the base and side of the valley
The material it gathers under the glacier (subglacial morraine) aids the process of abrasion
This widens and deepens the valley floor leaving a flat floor with v steep valley walks
A misfit stream will form and sometimes a hanging valley waterfall will

48
Q

How do hanging valleys form?

A

Large glacier is joined by a tributary glacier (because main lake was joined by a smaller lake)
The large glacier moves down v shaped valley and via erosion leaves a u shaped valley (a glacial trough)
The small glacier simultaneously erodes but erodes slower/less powerfully
Therefore it doesn’t erode to the same depth
As a result it looks like it’s hanging
Waterfalls sometimes form

49
Q

Learn glacial trough formation diagram

A

Okay

50
Q

What is a ribbon lake?

A

Long and thin lakes in the floor of a glaciated valley

51
Q

How do ribbon lakes form?

A

Glacier moves down hard rock, finding it hard to erode as rock is more resistant
When glacier reaches soft rock it can easily erode
This leaves a rock basin (hard rock steep compared to soft rock eroded in depth)
A band of hard rock follows the soft rock (glacier can’t erode this as much so it’s higher up than the soft rock)
A ribbon lake will form on the soft rock but be dammed by the rock bar / any morraine built up

52
Q

Egs of landforms of erosion

A 
Corrie
Pyramidal peak
arête 
Truncated spur
Glacial trough (u shaped valley)
Hanging valley
Ribbon lake
53
Q

What is a drumlin

A

A smooth elongated mound of Boulder clay which has been streamlined by ice

54
Q

Shape of drumlin

A

They have a broad and upstream stoss end and a gentle tapering lower downstream end (lee end)

55
Q

How do drumlins form

A

Melting glacier meets a small obstacle which is enough to encourage the deposition of till from the ice as the glacier had a low competence
On first meeting the obstacle the most deposition occurs (this forms the blunt stoss end)
The glacier mounds the till into shape around the obstacle which forms a tapered lee end
Overtime material is reshape by further i e movements

56
Q

Typical measurements of a drumlin

A

Up to 40 m high

400m long

57
Q

Flow diagram of ice

A

Ice erodes
Transports
Deposits
Landform is reshaped

58
Q

What is a fragile environment? Ecample?

A

A area which is easily damaged and would take a long time to recover

59
Q

Winter attractions at chamonix

A

Paragliding over glaciated landscape
Iceskating at chamonix ice rink
Winter mountaineering

60
Q

Summer attractions at chamonix

A

Sightseeing eg Aigulle du Midi
Hiking (350km trail)
Mountain biking (5 mile trail)

61
Q

How can human activity damage glacial environment?

A

Air pollution from vehicles / heat from hotels = increase local temp = melting of snow (loss of habitats)

Less snow on slopes = concentration of people further up mountains = more erosion at top of mountain

Less snow on slopes = snow machine = uses lots of water = affects hydrological system

Summer activities eg mountain biking = erosion, environment can’t recover

Deforestation/ removal of vegetation = increases risk of erosion, loss of habitat, decreases slope stability

62
Q

Positive impacts of tourism in chamonix

A

Brings in money which supports local services
Provides jobs
Experience of different cultures

63
Q

Negative impacts of tourism in chamonix

A

10000 people population swells to 100,000 in summer a day
Noise pollution due to tourism/congested roads
Footpaths eroded
Trees cut down to make way for skiing paths
Sking close to tress can damage them
Shops are tourist orientated
Inflation in some shops

64
Q

The three management strategies in chamonix

A

Tomorrows valley
Espace Mont Blanc
Respect the mountain

65
Q

What does tomorrow’s valley do/ who does it involve

A

Mix of locals and tourists : finds a balance
Maintains footpaths
Renovates historical monuments
Plants trees

66
Q

Whag does Espace Mont Blanc do/ who does it involve?

A

International issues betw France Italy and Switzerland
reduces pollution and congestion
Nature conservation

67
Q

How tourism can damage a glacial area ?

A

Air pollution from vehicle emissions / heat from hotels = increase local temp = melting of snow = habitats lost and erosion

Less snow on low slopes = people move up the mountain = more erosion up the mountain

Less snow on low slopes = snow machine = lots of water used up = effects hydrological system

Summer activities = eg mountain biking = leads to erosion, fragile environment can’t recover

Deforestation for skiing = habitats lost, slope instability, risk of erosion

68
Q

What does respect the mountain do?

A

Tells tourists why mountains are so important
Tells them to recycle and be respectful
Sell £2 wristband where profits go to tree planting to conserve environment

68
Q

How tourism can damage a glacial area ?

A

Air pollution from vehicle emissions / heat from hotels = increase local temp = melting of snow = habitats lost and erosion

Less snow on low slopes = people move up the mountain = more erosion up the mountain

Less snow on low slopes = snow machine = lots of water used up = effects hydrological system

Summer activities = eg mountain biking = leads to erosion, fragile environment can’t recover

Deforestation for skiing = habitats lost, slope instability, risk of erosion

69
Q

Types of avalanches

A 
Powder 
Soft slab
Hard Slab
Climax 
Wet
70
Q

Powder avalanches?

A

Windy but dry conditions

freshly layer of fallen cold snow is blown off

71
Q

Slab avalanches

A

Two types : soft (new powdery snow) and hard (old, more dense, chunkier snow)
Big range of mountain
Hard = more dangerous
A layer of rigid snow on top of a layer of softer, more mobile snow
Often set off by explosives to reduce impacts

72
Q

Climax avalanches?

A

Aka delayed action avalanches

weight of fresh snow causes rest of snow to succumb

73
Q

Evidence of human impacts on avalanches

A

100 or so natural avalanches at chamonix
10 set off by skiers off piste at chamonix
90% people who die in avalanches set them off themselves

76
Q

what is an avalanche

A

A mass on snow sliding down a valley under the influence of gravity

77
Q

Management of avalanches

A

Warnings sent out
They blow it up with dynamite
Afforestation (trees set up like a wall)
Snow fences/ barriers to trap snow eg Paravalanche de Tacconaz at chamonix
Avalanche proof tunnels

78
Q

What can make avalanches likely?

A

Heavy accumulation (snowfall on unstable area puts pressure on snowpack)
Steeper slope
Human activity (eg vibrations from mountain bikes)
Warm temp
Layers of snow turning to ice (fresh snow easily slides down)

79
Q

Wet avalanches?

A

Common in spring
Made up of wet snow
Either due to warmth/rainfall causing snow to melt off

Geog Things (4 decks)

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