Glaciers Flashcards

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1
Q

what is a glacier

A

mass of ice originated ON LAND by the recrystallization of snow AND shows evidence of past and present MOVEMENT

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2
Q

______ exceeds ______ in glaciers (snow fall vs snow melt)

A

snow fall EXCEEDS snow melt

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3
Q

four environmental significances of glaciers

A
  1. powerful agent of geomorphologic change
  2. source of freshwater (77% of all freshwater)
  3. release nutrients locked up in rocks
  4. contribute to changes in sea level
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4
Q

two terms associated with changes in sea level

A
  1. isostatic sea-level changes (related to land position)
  2. eustatic sea-level changes (related to water volume)
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5
Q

how is the sea level affected by the formation of glaciers and ice sheets

A
  1. eustatic FALL in the sea level (water is being taken out of the ocean and moved to land)
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6
Q

how is the sea level affected by the further growth of sea sheets

A

isostatic depression of land (land is being pressed DOWN because of the pressure above it) and a rise in sea level

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7
Q

how is the sea level affected by the melting of ice sheets

A

the eustatic rise in sea level (mass of glaciers on land is melting INTO the sea = decrease of freshwater on land)

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8
Q

how is the sea level affected by the decline of ice sheets and glaciers

A
  1. isostatic uplift of the land
  2. decrease in sea level BUT at the same time there is an eustatic rise in the sea level
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9
Q

the first year of snow for the glacial ice formation can be described as

A

mostly aid (not very dense)

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10
Q

what happens to the snow over the years in the formation of glacial ice

A

it begins to become compacted and denser (becomes firn) until it becomes glacial ice

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11
Q

describe the colour of glacial ice and why it is so

A

blue hue - based on it allowing light to pass through it and ONLY being able to absorb short light wavelengths (like blue light)

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12
Q

three major Canadian glacier locations

A
  1. Coridllera
  2. Baffin island
  3. Queen Elizabeth Islands
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13
Q

2 main types of glacier

A
  1. continental
  2. alpine
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14
Q

continental glaciers AKA

A

ice sheets

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15
Q

describe the area covered by ice sheets

A

it is extensive

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16
Q

does the ice cover the topography in an ice sheet

A

YES

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17
Q

describe the flow of ice sheets

A

unconfined due to gravity

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18
Q

example of ice sheets

A
  1. Greenland
  2. Antartica
  3. Laurentide ice sheet
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19
Q

are ice caps constrained

A

NO

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20
Q

what is smaller: ice sheets or ice caps

A

ice caps (have to be smaller than 50 000 km2)

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21
Q

describe the appearance of ice caps

A

dome-like surface or circular

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22
Q

locations of ice caps

A

polar and sub-polar regions
(Yukon, Canadian Arctic…)

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23
Q

describe the appearance of ice fields

A

NO dome-like surface

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24
Q

do ice field show restraint

A

YES

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25
Q

what are often produced by ice fields

A

outlet glaciers

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26
Q

ice shelves

A

where glaciers float out onto oceans

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27
Q

ice shelves are a mix of

A

fresh ice AND sea ice

28
Q

true or false
ice shelves are not sensitive to climate change and thus good indicators

A

false - are sensitive to climate change

29
Q

where do ice shelves ORIGINATE

A

on LAND

30
Q

true or false
valley glaciers only appear on some of the continents

A

false- appear on ALL of them

31
Q

where are valley glaciers contained

A

the flow is contained to the valley between two peaks

32
Q

what are valley glaciers commonly seen as (steep or gradual)

A

steep

33
Q
A

cirque glaciers

34
Q
A

piedmont glacier

35
Q
A

tidewater glaciers

36
Q

the movement of glaciers is driven by

A

weight and gravity

37
Q

inputs of glacier processes are the

A

accumulation zones (snow, ice, rain, avalanches)

38
Q

output of glacier processes are the

A

ablation zones (meltwater, debris, icebergs)

39
Q

together the outputs and inputs of glacier processes form the

A

mass budget (which forms the equilibrium line)

40
Q

equilibrium line altitude (ELA)

A

the highest elevation that a snowline reaches at the end of SUMMEr

41
Q

what can be used to track the glacier health and change

A

ELA (equilibrium line altitude)

42
Q

what is the terminus area

A

the lowest end of a glacier

43
Q

how does ice behave

A

in a plastic manner (by deforming and flowing under pressure)

44
Q

where does freeze and thaw take place in a glacier

A

at the base (regelation)

45
Q

how can ice behave in a brittle manner

A

by breaking and formin crevasses and ice falls

46
Q

what is the importance of water BELOW the glacier

A

lubrication (helps the glacier have spurts have rapid movement)

47
Q

crevasses are

A

cracks in the surface in response to stress

48
Q

what are some stresses that can cause crevasses

A

tension
friction with walls
compression

49
Q

does the ice flow always balance out with snow accumulation

A

NO

50
Q

surges are the

A

high speed movement to get ride of express mass

51
Q

erosion of material by ice can be by

A
  1. scarping
  2. polishing
  3. plucking
  4. bulldozing across surfaces
52
Q

polished rock

A

debris in ice with a smooth surface

53
Q

cirques

A

originated curved site of a small glacier

54
Q

tarns

A

small mountain lakes in former glacier hollows

55
Q

u-shaped valleys and fjords

A

past presence of glaciers

56
Q

aretes and horns

A

remnants of backwards erosion (it is a pyramid-shape or knife-edge ride)

57
Q

hanging valleys

A

glacial valleys above one another (tributary glacier valley)

58
Q

examples of glacial erosion

A
  1. polished drock
  2. ciruqes
  3. tarns
  4. u-shaped valleys and fjords
  5. aretes and horns
  6. hanging valleys
59
Q
A

tarn

60
Q
A

u shaped valley glacier

61
Q
A

Fjords

62
Q
A

horns

63
Q

horns show remnants of erosion on ____ sides and are where _____ come together

A

three or more AND cirques

64
Q

aretes have erosion on _____ sides

A

both (2)

65
Q

aretes are _____

A

ridges separating two adjacent glacier valleys OR cirques

66
Q
A

aretes glacier

67
Q
A

hanging valley glacier