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Glaciation Flashcards

1
Q

What are the two short term climatic events?

A

Loch Lomond Stadial (11,500 yrs ago) (glacial temp = 6-7 drop) (drainage of proglacial lake = lake agassiz)
Little Ice Age (1550-1750) (curling = nat sport scotland and abandonment of upland farms, river and nyc harbour froze!!)

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2
Q

What are the long term factors leading to climatic change?

A

Milankovitch Cycles

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3
Q

What are the short term factors leading to climate change?

A
  1. Solar forcing

2. Volcanic eruptions

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4
Q

How much sulfur dioxide was released from Tambora 1815?

A

200 million tonnes

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5
Q

What are the ice masses I gotta know?

A
  1. Valley glacier
  2. Cirque glacier
  3. Ice Sheet
  4. Ice fields
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6
Q

What are the factors affecting distribution of ice cover?

A
  1. Latitude (sun’s rays hit ground at lower angle etc…)

2. Altitude - ELR

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7
Q

Periglacial conditions: now VS Pleistocene?

A 
Now = 20%
Pleistocene = 33%
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8
Q

How much of Earth experiences permafrost conditions?

A

25%

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9
Q

Factors affecting permafrost?

A
  1. Amount of moisture avalible
  2. Slope of angle orientation
  3. Vegetation prescence
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10
Q

What are the four periglacial processes?

A
  1. Contraction and cracking of rapidly freezing soils = ice wedges, and frost heaving = patterned ground
  2. Migration of the sub-surface water to the freezing front by suction = segregated ice = ice lens = pingos
  3. 9% expansion of water on freezing = block fields and screes
  4. Mass movement of the active layer downslope = lobes and terraces
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11
Q

What are the three periglacial landforms?

A

Patterned ground
Ice Wedge Polygons
Pingos

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12
Q

Examples of the three periglacial landforms?

A

Patterned ground = Banks on the River Till
Ice Wedges Polygons = Tinto Hills
Pingos = Vale of Llanberis

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13
Q

What occurs during Freeze Thaw Weathering?

A
  1. Summer = meltwater = erosion of river and stream channels

2. Winter = deposition = braided channels

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14
Q

What are the inputs of the glacial system?

A
  1. Energy from the sun
    - evaporates water
    - form precipitation
    - air masses
    - snowfall = INPUT
  2. Masses
    - energy due to elevated position
    - e.g. debris/snowfall
    - energy used up as glacier moves, melts, or warms
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15
Q

Glaciers currently in retreat, case studies?

A
  1. Around 95% of Himalayan glaciers = rapid retreat
  2. On Eastern slopes of Rocky Mountains, all of the glaciers have lost between 25% and 75% of all their mass since 1850!!
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16
Q

What is the Khumbu glacier retreat?

A

5km since 1953!

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17
Q

What is the Antarctic ice loss?

A

250 billion tonnes a year! :O

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18
Q

What is the positive feedback loop of ice which is causing further melting?

A
  1. Less ice
  2. Loss of reflectivity (white)
  3. More dark surfaces exposed
  4. More heat absorption
  5. Further warming of the Earth
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19
Q

What rivers rely on meltwater from Himalayas?

A

Ganges
Mekong
Yangtze

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20
Q

Global warming on hydrological cycle?

A

Loss of supply of meltwater (mainly in early spring and summer)
Huge implications for populations of China & India
High demands of water for development as emerging superpowers - for industry & development & people’s quality of life

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21
Q

Management of the glaciated areas?

A
  1. Do nothing
  2. Business as usual
  3. Sustainable exploitation
  4. Sustainable management
  5. Total protection
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22
Q

Glaciated landscape - human threats?

A
  1. Industry
  2. Tourism
  3. Construction
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23
Q

Visitors in Antarctica?

A 
2012  = 34,000
2018 = 42,000
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24
Q

3 What is sustainable exploitation?

A
  1. Development for profit

2. Mandatory insistence on env. regulations

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25
Q

4 What is sustainable management?

A
  1. Resources for benefit of community
  2. Without destroying environment
  3. Conserving resources for future gen’s
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26
Q

1 What is ‘do nothing’?

A
  1. Total exploitation

2. Supported by TNC’s, developers, industrialists

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27
Q

2 What is ‘business as usual’?

A
  1. Leaving an area as it stands

2. May include pre-exisiting sustainability/ regulations

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28
Q

5 What is ‘total protection’?

A
  1. Complete conservation of environment

2. Environmentalists, researchers, locals

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29
Q

What is ANWR?

A

Artic National Wildlife Refuge

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30
Q

What did Trump do in ANWR?

A

In 2017, he passed the provision of opening up the 1002 area of the ANWR for oil and gas drilling

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31
Q

CNN Alaskan oil division?

A

59% support it

39% oppose it

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32
Q

Homes of Arctic tribes? (ANWR)

A

Inuit ppl

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33
Q

ANWR stakeholders/players? support

A

SUPPORT:

  1. National government
  2. Major oil companies
  3. Local people/local government (jobs, incomes)
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34
Q

Oil in ANWR?

A

Estimate of 10.4 billion barrels of oil!

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35
Q

ANWR stakeholders/players? against

A

AGAINST:

  1. Local/ national/ international pressure groups
  2. Native people
  3. Environmentalists
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36
Q

2 types of legislative frameworks to ‘protect and conserve glaciated landscapes’?

A
  1. International
    - 1959 ATS treaty (effective = 1961)
    - continent of peace and science
    - 54 parties
    - 12 signatories
    - four separate international agreements formed by ATS: inc CCAS and CCAMLR
  • Arctic issue: surrounded by 2 superpowers = USA & Russia
  • 4 million people live in Arctic
  • not just ice, ice and tundra !
  • Arctic Council (8 members) - 1996
  • only 15% of arctic is protected
  • ISSUE OF ARCTIC COUNCIL:
    + ‘peace and security issues were left out of it’s mandate’
    + climate change and melting of sea ice = water ways and energy resources are more accessible e.g. USA, Alaska, 1002 area
    + territorial disputes =
    + EEZ issue e.g. Russia and USA, Bering Strait and Chukchi Seas
    + NOW: some suggest peace and security issues should be brought to agenda
  1. National
    - ANWR
    - 1960
    - many animal species like caribou, bears, snow geese
    - ranngeee of stakeholders here e.g. major oil companies, tourists, locals, governments
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37
Q

ANTARCTIC AGREEMENT NAMES?

A
  1. CCAS
    Convention for the Conservation of Antarctic Seals
  2. CCAMLR
    Convention for the Conservation of Antarctic Marine Living Resources
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38
Q

Examples of global systems for conservation?

A

1 INDIVIDUAL SPECIES

  • CITES
  • 1973
  • many Arctic species e.g. polar bear, walrus
  • issue of ppl not sticking to this, e.g. Japan whaling
2 IUCN (international union for the conservation of nature)
- 'Red List' = endangered species = polar bears

3 UNESCO, WORLD HERITAGE SITES
- Wrangel Island (arctic), 2004 = 23 endemic species

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39
Q

What is the issue of global systems for conservation?

A
  1. Without real n strong enforcement
  2. Growing economic demands > oil etc… moving away from conservation
  3. Increasing nationalistic view and world on self serving motives e.g. Japan - withdrawals from global systems…
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40
Q

What is climate warming amplified by?

A

Positive feedback!

  1. More dark surfaces
  2. Melting of permafrost
41
Q

Futures of glaciated landscapes?

A
  1. Water insecurity will increase for some (Asia)
  2. Losses in carbon store from permafrost, peat etc…
  3. Predicted sea level rise of 0.5-0.75m by end of 21st century
  4. Complex changes in food webs
42
Q

What mitigation do we need for climate warming?

A

LOCAL, NAT AND INTERNATIONAAAL COOPERATION BABYYYYY

  1. Local = planning, recycling, transport
  2. National = energy, transport, taxation
  3. International = strategies e.g. COP21 Paris 2015, Kyoto 1997
43
Q

Factors affecting rate of glacial ice movement?

A

Ashley Tisdale Grinds Little Shit

  1. Altitude
    - high altitudes = higher potential energy = increase glacial movement
  2. Temp of ice
    - warm based = quicker (equlibrium shit) and ALTITUDE!
  3. Gradient
    - steeper = encourages quicker movement = move gravity = larger downslope force = pulls from bedrock and moves
  4. Lithiology
    - more easily eroded rock = deformations = slow down ice movement
  5. Size of glacier
    - rapidity of response
    - large glacier = slow movement = needs a larger downslope force to move
44
Q

Glacial movement?

A

Shear stress > resisting forces
Weight of snow and ice exerts downslope force due to gravity
Glacier pulls from bed rock and moves

45
Q

What does speed of glacier depend on?

A

Degree of imbalance/gradient btwn zones of acc and ab

46
Q

Types of glacial deposition?

A 
FLAD
FLOW
LODGEMENT
ABRASION
DEFORMATION
47
Q

Glacial entrainment?

A

SUPRAGLACIAL (valley glaciers)
SUBGLACIAL (mainly ice sheets)
ENGLACIAL (valley glaciers)

48
Q

Factors affecting glacial erosion?

A

Tamara Taylor Licks Shit

  1. Thickness of ice
    - thicker ice
    - more pressure exerted on bedrock
    - more likely to tear away
    - thicker ice = more erosion
  2. Thermal regime
    - warm based = debris and meltwater (facilitates erosional processes)
    - warm based = more erosion
  3. Lithiology
    - softer rock = eroded more easily
    - harder rock = eroded less easily
  4. Speed of glacier
    - faster = erodes more = high velocity = high energy = high erosive potential!
49
Q

Types of glacial erosion?

A

ABRASION
PLUCKING
DILATION
MELTWATER EROSION

50
Q

Abrasion?

A

Scraping or wearing away of individual clasts which leads to microfeatures e.g. striations.
The rock flour also polishes the underlying bedrock by sandpaper actioooon

51
Q

Glacial trough?

A

A steep sided flat floored straight valley

52
Q

What is hanging valley resulted from?

A

Differential rates of erosion

- main valley glacier erodes fast

53
Q

Things to enlarge corrie?

A
  1. Nivation
  2. Positive feedback
  3. Plucking and abrasion = overdeepening
54
Q

What can be left after a glacier melts from a corrie?

A

A tarn (lake)

55
Q

Glacial depositional landforms?

A
  1. Erratics
  2. Moraine
    - medial
    - lateral
    - recessional
    - terminal
  3. Drumlin
56
Q

Longer term causes of climate change?

A

Milankovitch Cycles, 1920’s

  1. Eccentricity
    - elliptical to more circular and back again: 100,000 years
    - amount of radiation recieved by sun
  2. Axial tilt
    - 21.8 to 24.4
    - now 23.5
    - over 41,000 years
    - changes intensity of sunlight @ poles, seasonality of earth’s climate
    - bigger tilt: bigger diff between summer and winter
  3. Precession/wobble
    - changes point in year where earth is closest to the sun
    - over 21,000 period
    - WHEN diff seasons occur
57
Q

Negative feedback?

A

^ evap
^ global cloudy skies
^ inc pollution from industrialisation adds to cloud cover
^ global dimming
^ reflect solar energy back to space = white
^ cooling

58
Q

Why does warm water in Arctic disrupt THC?

A
  • less warm water drawn north to arctic

- cooling in northern europe

59
Q

Maunder Minimum?

A

1645-1715

longer period w no sunspot activity

60
Q

Tambora ejection?

A

200 mil tonnes of sulphur dioxide

61
Q

What does cyrosphere consist of?

A

Lake ice, sea ice, ground ice (permafrost), glaciers, ice shets, snow cover

62
Q

Ice masses I gotta know?

A
  1. Ice sheets
    - large masses of glacial ice that cover entire landscapes
    - antarctica: 14 mil sqkm2!
  2. Valley glaciers
    - confined btwn valley walls and terminating in a narrow tongue
    - e.g. Athabasca, Canada
    - 3-1500km2
    - from ice cap/sheet or cirque
  3. Cirque glaciers
    - occupying hollow, corrie on mountain side
    - e.g. Hodges South Georgia
    - 0.5-8 sqkm2
  4. Ice field
    - large area of interconnected glaciers
    - colder climates
    - higher altitudes
    - moutaneous region
    - patagonia icefield (chile & argentina)
    - less than 50,000sqkm2
63
Q

WARM BASED GLACIERS?

A
  1. TEMP OF SURFACE LAYER MOVES ABOVE AND BELOW FREEZING
  2. INCREASED PRESSURE = WATER = LIQUID BELOW 0 DEGREES
  3. BASAL ICE MELTING CONTINOUS = @ PMP

Why isn’t glacier frozen to bed? Due to effects of:

  1. Percolation
  2. Geothermal energy
  3. Pressure
64
Q

COLD BASED GLACIERS?

A
  1. EXTREME SURFACE TEMP = -20 TO -30
  2. LITTLE SURFACE MELT = LITTLE MELTWATER PERCOLATES DOWN
  3. FROZEN TO BED
65
Q

Glacial ice coverage?

A

10% of Earth’s land area

85% in Antarctica

66
Q

Periglacial: before and after?

A

Pleistocene: 33%
Now: 20%

67
Q

Factors affecting distribution of ice cover?

A

1 LAT
- suns rays hit ground @ lower angle = heat a larger area = a lot of ice coverage = sun cannot physically heat a larger area

2 ALT

  • ELR
  • rate of atmospheric temp decreasing with altitude at a given time and location
  • colder at high alts = little solar energy = ice cover high = no heating :(
68
Q

Ice cover: Pleisto V now?

A

Ice cover was X3 greater in Pleistocene than present day!!!!

69
Q

Periglacial characteristics?

A
  1. Low precip = under 600mm a year
  2. Intense frosts in winter and on any snow free ground in summer
  3. Temp below -10 for at least 6 months and below 0 for at least 9 months
  4. Temp’s rarely rise above 18dc, even in summer!
70
Q

Periglacial processes to create upland landforms?

A
  1. Mass movement of active layer downslope
    - ice creep
    - solifluction
    - lobes and terraces
  2. Freeze thaw weathering
    - block fields and screes
    - perfect temp = -4 to -15
  3. ‘Contraction and cracking of rapidly freezing soils’
    - ice wedges
    - and frost heave: patterned ground
71
Q

Freeze thaw weathering temp?

A

Perfect = -4 to -15

72
Q

Types of permafrost?

A
  1. Continous
    - hundreds of metres
    - air temps of -6
  2. Discontinous
    - more fragmented and thinner
  3. Sporadic
    - few m deep
    - air temps = freezing
73
Q

Active Layer?

A

Top layer of soil in permafrost *** environments that melts during summer and freezes during winter

74
Q

Periglacial

A

Areas of freezing and thawing

75
Q

Why are periglacial landscapes more vulnerable to climate change?

A
  1. melting of permafrost
  2. no glaciated are: albedo
  3. both are: positive feedback loops
76
Q

Permafrost temp increase?

A

Every 1 degree temp rise, there could be a 1.5 million sq mile of permafrost loss through thawing

77
Q

Factors affecting permafrost?

A
  1. temp and amount of moisture avalible: degree, depth, prescence
  2. slope of angle orientation: amount of radiation: continous vs discontinous = dis = more radiation
78
Q

What is nivation?

A

Occurs when both weathering AND erosion takes place around and below a snowpatch

  • w and e
79
Q

What to remember about Sandurs?

A

Biggest material deposited first

80
Q

Blockfields?

A

Acc of angular frost shattered matieral

  • flat plateau surfaces
  • frost heaving of joint bedrock and ftw
81
Q

Tor?

A

Free standing rock outcrop

82
Q

Screes?

A

When rock fragments fall & acc on base/lower slopes of cliffs

BASE OR LOWER SLOPES !!!!!!

83
Q

Glacial ice formation?

A
  1. Accumulation of permanent snowfield
  2. Compacted
  3. Granular (0.1gcm of density)
  4. Compressed
  5. Neve/firn
  6. Density increases: PIM and refreezing of water into gaps
  7. Deeper layers of firn transported into glacial ice (0.9gcm of density)
  8. Outwards or downwards by extrusion flow
84
Q

What is glacial ice?

A

Primarily compacted snow, with other contributions from precip e.g sleet/hail

85
Q

Neve/firn?

A

Crystalline or granular snow where it hasn’t been compressed to ice

86
Q

Mass Balance?

A

Gains or losses of the ice store of the glacial system

87
Q

Eskers: ice contact fluvioglacial

A

Sinous ridges of sand and gravel deposited by meltwater flowing thro tunnels
Obstruction of subglacial/englacial tunnel causes fluvioglacial matieral to be deposited upstream
Blakeney Esker, Norfolk

88
Q

Processes of water movement?

A
  1. Supra
  2. En
  3. Sub
89
Q

Cyrosphere?

A

Parts of Earth’s surface subject to temps below 0 degrees for at least part of each year

90
Q

Solifluction?

A

Gradual movement of soil saturated with meltwater downslope over a permanently frozen ground in tundra regions

91
Q

Example of block fields?

A

On the summit of Derry Cairngorm

92
Q

Freeze thaw weathering for dummies?

A

FEEM

  1. Water into crack
  2. Freezes
  3. Ice expands > enlargening crack
  4. Ice melts
  5. More water comes in and same thing happens!
  6. Continues to happen until rock breaks
93
Q

Pingo diameter?

A

100-500m

94
Q

Regimes in the summer?

A

Negative regime

  • more ablation than accumulation
  • glacier shrinks and snout retreats
95
Q

Regimes in the winter?

A

Positive

  • few days above 0 degree
  • more acc than ab
  • glacier grows and snout advances
96
Q

Health of glacier?

A
  1. Altimetry
    - surface elevation> thickening thinning expanding shrinking
  2. Gravimetry
    - gravt attraction = changes in mass
  3. Mass budget method
    - compares snowberg ice calving density with snow acc
97
Q

Benchmark glacier?

A

A designated glacier in which it’s accumulation and ablation rates are measured annually used standardized techniques to monitor impacts of CC

e. g. Sperry –> Montana
e. g. Gulkana –> Alaska

98
Q

Cause of ice movement?

A

Gravity

  • weight of snow and ice cause an increased downslope force due to gravity
  • then sheer stress over comes the resistive forces, glacier pulls from bedrock and moves
99
Q

Speed of glacier depends on?

A
  1. Degree of imbalance or gradient between zone of accumulation and ablation

Glaciation (1 decks)

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