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Edexcel Geography A Level > Glaciated Landscapes and Change > Flashcards

Glaciated Landscapes and Change Flashcards

1
Q

What do periglacial processes include?

A
  • Nivation, frost heave, freeze thaw weathering, solifluction, high winds, meltwater erosion
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2
Q

What are 4 unique periglacial landforms?

A
  1. Ice wedges 2. Patterned ground 3. Pingos 4. Loess
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3
Q

What are the three processes of accumulation?

A
  1. Direct snowfall 2. Avalanches 3. Wind depostion
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4
Q

What are the five processes of ablation?

A
  1. Melting 2. Sublimation 3. Calving 4. Evaporation 5. Avalanches
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5
Q

What are the three different processes that are important in the movement of glaciers?

A
  1. Basal slip 2. Regelation creep 3. Internal deformation
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6
Q

What are 5 factors that affect the rate of movement in glaciation?

A
  1. Altitude 2. Slope angle/gradient 3. Ice thickness 4. Bedrock permeability 5. Variations in mass balance (ice temp, rates of ablation and precip)
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7
Q

How and when were ice ages discovered?

A

In 1830s by Louis Agassiz in the Swiss Alps. Identified that they had occurred all over Europe, saw that certain areas had similar features

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8
Q

What is the theory of Uniformitarianism?

A

The assumption that the same natural laws and processes that operate in our present day scientific observations have always operated in the universe in the past and apply everywhere in the universe

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9
Q

What does glacial and interglacial periods mean?

A

Glacial - period of intense cold
Interglacial - period between glacial periods

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10
Q

How have ice cores helped determine past climates?

A

Bubbles trapped in the ice contain CO2 from the atmosphere

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11
Q

What epoch are we currently living in?

A

Quaternary epoch

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12
Q

What are epochs?

A

Periods of geological time. These relate to times of the past where geological strata were laid down. Epochs denote changes such as mass extinctions

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13
Q

What three epochs is the quaternary period divided into and explain them

A
  1. Pleistocene - covers the beginning of the quaternary period, this is the age we will study in detail 2. Holocene - interglacial period of man 3. Anthropocene - begins from when there was significant human impact on Earth until now, including such things as biodiversity loss and climate change
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14
Q

Does the Pleistocene epoch have multiple glacial and interglacial periods?

A

Yes, causes the landscape to remould and reshape each time, this makes it complex to reconstruct the past

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15
Q

How many years roughly is there a new glacial or interglacial period?

A

Every 100,000 years

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16
Q

Give another way glacial landscapes can be modified other than other glacial periods

A

Geomorphological processes

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17
Q

What are stadials and interstadials?

A

Stadials - smaller fluctuations and shorter periods of intense cold
Interstadials - shorter periods of relative warmth
Recent ice core analysis show these to be sometimes quite abrupt changes

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18
Q

Give the 5 types of glacial erosion

A
  1. Quarrying 2. Plucking 3. Abrasion 4. Crushing 5. Basal melting. These all combine with subaerial freeze thaw and mass movement
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19
Q

Give the 7 upland erosional features

A
  1. Cirques/corries 2. Aretes 3. Pyramidal peaks 4. Glacial troughs 5. Truncated spurs 6. Hanging valleys 7. Ribbon lakes
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20
Q

Give the 4 landforms due to ice sheet scouring

A
  1. Roches moutonnees 2. Whalebacks 3. Knock and lochan 4. Crag and tail
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21
Q

What is the pleistocene?

A

Covers the beginning of the quaternary period, glacial epoch. around 2,588,000 to about 11,700 years ago

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22
Q

What is precession?

A

A gradual change, or wobble, in the orientation of Earth’s axis affects the relationship between Earth’s tilt and eccentricity

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23
Q

When did the quaternary period start?

A

2.588 million years ago!!!!!!!! wow

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24
Q

How many years of climate can ice cores track back to?

A

800,000 years

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25
What is the first milankovitch cycle theory and how often does this happen?
Eccentricity of orbit - happens every 100,000 years
26
How often does axial tilt happen?
41,000 years
27
How often does precession happen?
Every 21,000/22,000 years
28
Spell the volcano in Iceland that sir wants you to spell for some reason
Eyjafjallajokull
29
What are the three reasons for glacial deposition?
1. When the velocity is reduced 2. They become overloaded with debris 3. When ablation increases
30
What are the six ice contact depositional features?
1. Erratics 2. Medial moraines 3. Lateral moraines 4. Recessional moraines 5. Terminal moraines 6. Drumlins
31
What are the two types of till plains (lowland depositional features)?
1. Lodgement till 2. Ablation till
32
Explain the eccentricity of orbit as a primary cause of climate change. 4 points
1. Elliptical earth orbital cycle to circular every 100,000 years 2. Amount of solar radiation received in high eccentricity orbit varies greatly, increase in magnitude of seasonal changes 3. Low eccentricity leads to low seasonality - promotes glaciation 4. As a result, temps at high latitudes in northern hemisphere increase
33
Explain obliquity as a primary cause of climate change. 5 points
1. Axial tilt varies from 21.8 degrees to 24.4 degrees, currently at 23.5 , 2. 41,000 year timescale 3. Impacts intensity of light received at poles - seasonality of Earth 4. Less tilt=warmer winters but cooler summers - glaciers do not melt in summer - advance, low obliquity=low seasonality 5. Glaciers will reflect more of incoming solar radiation further cooling planet
34
Give four different characteristics of glacial and fluvioglacial deposits
1. Stratification 2. Sorting 3. Imbrication 4. Grading
35
Give three formations of fluvio-glacial ice contact features
1. Kames 2. Eskers 3. Kame terraces
36
Give four fluvio-glacial proglacial features
1. Sandurs 2. Pro-glacial lengths 3. Meltwater channels 4. Kettleholes
37
Explain precession as a primary cause of climate change in 5 points
1. The earth wobbles on its axis changing the point in time the earth is nearest the sun (21,000/22,000 year cycle) 2. Means that the North Pole points both towards and away from the sun increasing the variation in the irradiation of the Northern Hemisphere 3. Causes variation in summer and winter temperatures and so causes variations in ice volume 4. Precession (tilt direction) works in conjunction with eccentricity to control the level of insolation at 65 degrees north 5. Glaciation is favoured when the direction of the tilt is such that N.hemisphere summers are at the largest earth-sun distance
38
How much do the Milankovitch cycles affect the temperature by?
1 to 1.5 degrees
39
How many degrees change does there need to be for ice to form?
5 degrees
40
Give an example of positive feedback
Small increases to snow and ice cover can raise surface albedo (the quantity of reflection of sunlight) - more solar radiation is reflected back into space - could lead to more snow and ice cover
41
Give two examples of negative feedback
1. Increases global warming and industry leads to more evaporation which increases cloud cover - increased cloud cover reflects solar energy back into space - reducing the intensity of global warming 2. Ice sheet dynamics disrupt thermal heating circulation - warming waters in the Arctic disrupts ocean currents - less warm water from the gulf stream creating global cooling in N.Europe
42
Explain solar forcing in 4 points
1. Energy emitted by the sun varies due to sunspots. Cycling every 11 years, date back to 400yrs 2. 1645 to 1715 - Maunder Minimum 3. 950 to 1250 - Medieval Warm Period 4. Seen as contributing to 20% of global warming in 20th Century
43
Explain volcanic causes as a short term fluctuation for climate change in 4 points
1. Many past examples where volcanoes alter temp 2. VEI 7+ volcanoes eject huge amounts of Sulphure Dioxide, CO2 and water vapour into atmosphere 3. These block out sunlight 4. 1815 - Tambora in Indonesia caused temps to drop by 0.4 to 0.7 for 2-3 years
44
Explain the Loch Lomond Stadial in 6 points
1. When Lake District formed, occured 11,700BP to 12,900 BP 2. Ice sheets began to melt at 18,000BP 3. Rapid deglaciation 15,000BP ago. Similar temps to today 4. 12,500 BP glacial conditions reoccurred and by 11,500BP temps were 6-7 degrees lower than today 5. Glaciers readvanced all over the world including Scotland, Lake District and Snowdonia 6. Reason: Believed to be due to the draining of Lake Agassiz into Atlantic disrupting THC by cutting poleward heat from the gulf stream
45
Explain the Little Ice Age in 7 points
1. Proxy records tell us that between 1350 to 1900 there was a trough of cold temperatures having many impacts 2. Abandonment of many hill farms in Northern Europe 3. Glaciers advanced down valleys 4. Arctic sea ice spread further south with Polar Bears found in Iceland 5. Rivers froze in the UK, lowland Europe and New York 6. Curling developed as a sport in Scotland 7. Never developed into a full stadial due to Industrial Revolution
46
Why are glaciers a visible barometer of climate change?
They constantly shrink/retreat and grow/advance in response to changes in temperature
47
What is the cryosphere?
Part of the earth's crust and atmosphere subject to temperatures below 0 degrees celcius for some part of the year.
48
What are the two distinct roles of the cryosphere?
1. It helps to regulate climate via the albedo effect 2. It is also a global store of freshwater
49
What is an ice sheet?
A layer of ice covering an extensive tract of land for a long period of time
50
What is an ice cap?
Miniature ice sheets, form primarily in polar and sub-polar regions that are relatively flat and high in elevation
51
What is a valley glacier?
Glacier confined by valley walls
52
What is a cirque glacier?
Are named for the bowl-like hollows they occupy, which are called cirques
53
What are unconstrained glaciers?
Tend to be larger forms such as ice sheets and ice caps. These are thick and extensive and often submerge the landscape
54
What are constrained glaciers?
Those that have a physical limit such as valley glaciers where the landscape constrains where they are and tend to only drain one way
55
What is a warm based glacier in 6 points?
1. Temperate or wet glaciers occur at high altitude areas outside of polar regions 2. Temperatures fluctuate on the surface to above and below freezing 3. The rest below the surface is close to melting point because the pressure builds up 4. Because of this water exists as a liquid at temperatures below 0 degrees 5. Having liquid at the bottom causes them to melt continually 6. The ice also has lots of debris at the bottom and this creates many subglacial deposits and landforms
56
Describe cold-based glaciers in 4 points
1. Polar glaciers where average temperature is often below 0 degrees with surface temperatures of -20 to -30 degrees 2. The temperature at the base is still below freezing even though the ice could be 500m thick 3. Limited surface melt during the polar summer and so the glacier is permanently frozen to the bed 4. The basal layer therefore has far less debris within it
57
What is pressure melting point?
The temperature at which ice begins to melt under a given amount of pressure
58
Describe past and present ice distribution
1. Glacial ice covers over 10% of the earth's land surface 2. It accounts for 75% of all freshwater stores 3. 1.8% of all water on planet
59
Where are places glaciers can be found?
85% of all glacier ice is contained within the Antarctica Ice. The rest is distributed amongst ice caps all over the world; Iceland, Canada, USA, Himalayas, Andes, Alps
60
What are the two most important factors governing where ice found is?
Latitude - For polar ice caps Altitude - For Alpine glaciers

Edexcel Geography A Level (3 decks)

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