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Glaciated landscapes Flashcards

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1
Q

UNIT 1
What is a glacier?

A

Moving body of ice

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2
Q

UNIT 1
How far do some glaciers move per day?

A

Up to 25cm per day

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3
Q

UNIT 1
Why do glaciers move?

A

Gravity forcing them down

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4
Q

UNIT 1
Why are glaciers important and how many people rely on them?

A

Drinking water, crop irrigation, tourism, recreation and hydroelectricity
1/3 of the world’s population rely on glaciers

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5
Q

UNIT 1
What is happening to many glaciers around the world?
What does this cause?

A

Many glaciers around the world are melting (negative mass balance).
This is causing sea levels to rise 2.6m in the last 60 years, causing extinction of animals, loss of resources, ecosystems and habitats

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6
Q

UNIT 1
Where are glaciers found

A

High latitude (poles) and altitude (mountainous) locations, where the temperature is regularly below 0 degrees Celsius (Cryosphere)

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7
Q

UNIT 1
Examples of accumulation (inputs) of snow.

A

Wind blown snow, Precipitation, desublimation (condensation into ice), avalanche debris.

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8
Q

UNIT 1
Examples of ablation (outputs) of snow

A

Meltwater, Calving (breakaway of ice), Rock debris, wind-blown snow, avalanche debris, solar energy, sublimation (evaporation from ice).

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9
Q

UNIT 1
Where does accumulation occur?
Where does ablation occur?
What is the line of equilibrium?

A

accumulation at head
ablation at toe
line of equilibrium is where inputs = outputs

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10
Q

UNIT 1
Describe the formation of glaciers

A

Snow falls, which contains ait, more snow falls, compacting the pre existing snow. Snow that survives one winters freezing and one summers thawing is called firn. In summer meltwater percolates into the firn, in winter it refreezes, causing it to become denser. After several years and a depth of 20m, there is very little air left and glacial ice is formed.

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11
Q

UNIT 1
What is mass balance?
Positive?
Negative?

A

UNIT 1
Mass balance is the growth or retreat of a glacier
Positive - growth
negative - retreat

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12
Q

UNIT 1
Draw a Glacier flow diagram

A

:)

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13
Q

UNIT 1
What is till?

A

Unsorted material deposited directly by glacial ice

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14
Q

UNIT 1
What is a moraine?

A

Deposited sediment from a retreating glacier

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15
Q

UNIT 1
Moraines formation

A

Till is deposited by glacier, debris dropped on top of glacier and material eroded from plucking.
Retreating glacier causes sediment to be deposited, causing a recessional moraine to form

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16
Q

UNIT 1
Glacier advance and retreat

A

Positive mass balance means glacier advances, becoming thicker and ploughs over moraines.
Negative mass balance means glacier retreats, but is still flowing forward due to gravity, causing the glacier to become thinner.

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17
Q

UNIT 1
Mass balance graph and description:

A

In winter there is lots of accumulation, in spring and autumn there is equal amounts of accumulation and ablation in summer there is more ablation then accumulation.

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18
Q

UNIT 1
What percentage of glaciers currently have a negative mass balance

A

75%

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19
Q

UNIT 1
How much of the earth’s surface is covered by glaciers?

A

10%

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20
Q

UNIT 1
How much of the world’s freshwater is stored in glaciers?

A

75%

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21
Q

UNIT 1
What is a ice period

A

permanent ice at the poles

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22
Q

UNIT 1
What is an interglacial period?

A

Periods of warm, causing glaciers to have a negative mass balance

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23
Q

UNIT 1
What is a Glacial period?

A

Period of cold, causing glaciers to have positive mass balance.

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24
Q

UNIT 1
When was the Holocene period
Interglacial or Glacial?

A

11,500 ybp to present
Interglacial

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25
Q

UNIT 1
When was the Devensian period?
Interglacial or Glacial?

A

80,000 ybp to 11,500 ybp
Glacial

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26
Q

UNIT 1
When was the Ipswichian period?
Interglacial or Glacial?

A

80,00 ybp to 100,000 ybp
Interglacial

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27
Q

UNIT 1
When was the Wolstonian period?
Interglacial or Glacial?

A

100,000 ybp to 140,000 ybp
Glacial

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28
Q

UNIT 1
When was the Hoxian period?
Interglacial or Glacial?

A

140,000 ybp to 200,000ybp
Interglacial

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29
Q

UNIT 1
Why do cycles of Interglacial or Glacial periods exist?

A

Changes in long-term cyclical change, due to changes in Earth’s orbits around to sun, leading to a variation of insolation received by the earth, caused mostly by Milankovitch cycles.

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30
Q

UNIT 1
What is the current tilt of the axis of the earth?

A

23.5 degrees

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31
Q

UNIT 1
Perihelion meaning.
Aphelion meaning.

A

Closest point to the sun
Furthest point from the sun

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32
Q

UNIT 1
UNIT 1
Winter solstice
Summer solstice
Equinox

A

Shortest day
Longest day
Equal insolation of both hemisphere

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33
Q

UNIT 1
What are Milankovitch cycles?
How much of they impact the amount of incoming insolation

A

Orbital variations.
Causing up to 25% variation

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34
Q

UNIT 1
Stretch (eccentricity) of the orbit description
Impacts
Time frame

A

Impact of orbital shape (more oval vs more circular). At most elliptical there is 23% more insolation then at furthest point. Every 100,000 years

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35
Q

UNIT 1
Axis tilt (Obliquity).
Impacts
Time frame

A

Tilt of the earth, varies between 22.1 and 24.5 degrees. Tilted towards the sun causes warmer climates, vice versa.
Over 41,000 years

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36
Q

UNIT 1
Wobble (precession)
Impacts
Time frame

A

earth wobbles in orbit due to the relationship between the sun and moon (Tidal forces). Causes variations in temperatures. Takes 25,771.5 years

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37
Q

UNIT 1
What is long term climate change caused by?

A

Milankovitch cycles

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38
Q

UNIT 1
What is responsible for glacial and interglacial periods?

A

Milankovitch cycles

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39
Q

UNIT 1
What is positive feedback in relation to glacial budget

A

Positive feedback amplifies changes in a glacial budget. Cooling leads to further cooling, warming leads to more warming

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40
Q

UNIT 1
What is surface albedo?

A

Earth’s reflectivity

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41
Q

UNIT 1
Why is it important to have high surface albedo?

A

More reflective surfaces, so more insolation is reflected back into space, causing decrease in temperature.

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42
Q

UNIT 1
What happens when there is low surface albedo?

A

Ice has melted, so there are less reflective areas, Insolation is absorbed into water, causing the temperature to increase

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43
Q

UNIT 1
How much insolation is reflected and absorbed by ice and snow (high albedo)

A

90% reflected to space
10% absorbed
(lower temperatures)

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44
Q

UNIT 1
How much insolation is absorbed/reflected with water (low albedo)

A

6% reflected
94% absorbed
(temperatures increase)

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45
Q

UNIT 1
Positive feedback relationship in with positive mass balance

A

Cooling of climate, Artic sea water freezes (ice cover increases), Darker surfaces hidden, increased albedo, decreased absorption of insolation…

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46
Q

UNIT 1
Positive feedback in relationship with negative mass balance

A

Increases in temperature, Artic sea ice melts, darker surfaces revealed, Albedo reduced, Increased absorption of solar radiation.

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47
Q

UNIT 1
Why is it hard to undo glacial melting

A

Warming leads to more warming due to positive feedback loops.

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48
Q

UNIT 1
Negative feedback in relation to glacial budget

A

Negative feedback reduces changes in a glacial budget. Warming leads to cooling

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49
Q

UNIT 1
Give an example of negative feedback in relation to glacial budget

A

Younger Dryas, due to thermohaline

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50
Q

UNIT 1
What is the thermohaline ocean circulation

A

Brings warm salty water to northwest Europe, causing warm winter conditions.

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51
Q

UNIT 1
What happens to cold water vs hot water

A

Cold water sinks
Hot water rises

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52
Q

UNIT 1
What is the Younger Dryas period

A

Towards the end of the last glacial period (Devensian) when temperatures were rising, the disruption to this ocean current in the North Atlantic led to a rapid period of cooling known as the Younger Dryas.

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53
Q

UNIT 1
When did the Younger Dryas occur?

A

13.25 thousand ybp to 11.25 thousand ybp

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54
Q

UNIT 1
How long did Younger Dryas period last

A

2 thousand years

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55
Q

UNIT 1
What was the drop of temperature in Greenland during the Younger Dryas?

A

-35 to -50 degrees celcius

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56
Q

UNIT 1
What was the change of ice accumulation in the Younger Dryas period

A

0.25 -> 0.32

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57
Q

UNIT 1
Explain how thermohaline currents caused the Younger Dryas period

A

Northern regions heated by the oceans. Ocean circulation is driven by Coldwater sinking in the North Atlantic. 12,800 years ago, freshwater made surface water less dense, keeping it from sinking. Air became colder for more then 100 years due to lack of northward transport of warm water. Northern Hemisphere has conditions like the last ice age. Rewarming occurred 11,600 years ago, within less then a decade ocean circulation was restored.
https://www.youtube.com/watch?v=kqWIwp1beIw

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58
Q

UNIT 1
Give 3 short term causes of climate change

A

Solar forcing (sunspots (increased solar outputs), Volcanic eruptions, Anthropogenic (human) factors.

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59
Q

UNIT 1
What is solar forcing?

A

Energy released by sun

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60
Q

UNIT 1
What is solar output linked to?

A

Sun spot activity

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61
Q

UNIT 1
How often do sunspots fluctuate?

A

On an 11 year cycle

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62
Q

UNIT 1
What was the little ice age caused by?

A

Low level of solar outputs

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63
Q

UNIT 1
When was the little iceage?

A

1645-1715

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64
Q

UNIT 1
What happened during the little ice age?

A

Sea ice expanded into Atlantic, Iceland and Greenland were impossible to ship too.
Baltic sea, rivers in the UK (like the Thames) froze over.
Permanent snow in Scotland covered Cairngorm mountains.
Glacier advanced in the Alps and threatened nearby towns

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65
Q

UNIT 1
Why do volcanic eruptions impact glaciers

A

Volcanoes release sulphur dioxide and ash into stratosphere, these reflect income solar radiation, leading to a decrease in temperature.

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66
Q

UNIT 1
Give three examples of Volcanoes that have impacted on climate change

A

Laki, Iceland, 1783, Europe was 3 degrees Celsius lower.
Tambora, Sumbawa Island, 1815, reduced temperatures by 0.7 degrees Celsius for 3 years
Mount Pinatubo, 1991, decreased temperatures by 0.4 degrees Celsius.

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67
Q

UNIT 1
What is Anthropogenic factors of short term climate change

A

Human activity linked to combustion of fossil fuels, releasing greenhouse gasses, causing enhanced greenhouse effect.

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68
Q

UNIT 1
How much has temperatures increased by due to anthropogenic factors

A

1.2 degrees Celsius since 1880

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69
Q

UNIT 1
How much of the Himalayas glaciers are in retreat?

A

95%

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70
Q

UNIT 1
How far were glaciers in the Himalayas retreating?

A

10-60m a year. Many small valley glaciers retreat 1km since the little ice age. Small glaciers have already dissapeared

71
Q

UNIT 1
How much higher are temperature in the Himalayas? What effect is this having?

A

+ 1.6 degrees overall. Decreasing amounts of snowfall

72
Q

UNIT 1
What percentage of glacier mass in the Himalayas are at risk?

A

1/4 of glacial mass could disappear by 2050

73
Q

UNIT 1
How far has the Chota Shigiri Glacier in the Himalayas retreated?

A

950m from 1962 to 2008

74
Q

UNIT 1
Where is the Glacier National Park USA

A

Montana

75
Q

UNIT 1
By what year will the Glacier National park be glacier free?

A

2030

76
Q

UNIT 1
How many Glaciers have disappeared in the Glacier national park since 1850?

A

In 1850 there were 150, in 2010 there was 25

77
Q

UNIT 1
Why do New Zealand have areas of glacial growth?

A

Westerly atmospheric circulation, causing increased snowfall. Causing positive mass balance

78
Q

UNIT 1
Why do areas in New Zealand have zero ice mass balance?

A

Equal amounts of loss and gain of ice

79
Q

UNIT 1
Why are some areas in New Zealand glacial retreats

A

Glacial lakes have begun to grow at snouts. Causing calving away from the glacier into icebergs. Glaciers with lakes attached have lost 10% of mass over 30 years.

80
Q

UNIT 1
What was ice extent like during the Devensian? What else did this impact upon?

A

Ice reached much further south, covering parts of the UK. Sea ice reached Iceland and Greenland. Due to this coastlines were much bigger as there were lower sea levels

81
Q

UNIT 1
Why are Glaciers found at high latitudes?

A

Axis tilt of earth means they get less sunlight, meaning snow can fall consistently and meltwater will refreeze

82
Q

UNIT 1
Why are glaciers found at high altitudes?

A

Low pressure, cool air (due to work done to rise), causing snowfall

83
Q

UNIT 2
What is the cryosphere?

A

Parts of the crust and atmosphere that are below zero degrees for a part of the year

84
Q

UNIT 2
How are icebergs formed

A

Broken of of glaciers into water via calving

85
Q

UNIT 2
What is permafrost

A

permanently frozen ground

86
Q

UNIT 2
What is the morphology of glaciers?

A

Form, shape and structure of ice

87
Q

UNIT 2
What two factors impact the morphology of a glacier?

A

Climate and topography of land

88
Q

UNIT 2
What is climate? And how does it impact a glacier’s morphology

A

Climate is contorlled by annual temperature cycle. Warmer climate causes negative mass balance vice versa.

89
Q

UNIT 2
What is topography? And how does it impact glaciers morphology?

A

Topography is the natural shape of the land. Land surface, e.g. altitude. Controls physical dimensions of the glaciers and how they can flow.

90
Q

UNIT 2
What is an unconstrained land mass?

A

morphology and flow pattern that is not fully dependent of the topography of land

91
Q

UNIT 2
What is a constrained ice mass?

A

Morphology and flow pattern that is strongly based on topography

92
Q

UNIT 2
Ice sheet:
Description, size, constrained or unconstrained?
Example

A

Topography is submerged in ice, forms gently sloping domes of ice several km thick. +50,000km2. Unconstrained. Antarctic ice sheet

93
Q

UNIT 2
Ice cap:
Description, size, constrained or unconstrained?
Example

A

Smaller version of an ice sheet. >50,000km2. Unconstrained. Vatnajökull ice sheet

94
Q

UNIT 2
Ice field:
Description, size, constrained or unconstrained?
Example

A

Ice covering upland area, does not bury topography. 10-10,000km2. Constrained. Patagonian ice fields

95
Q

UNIT 2
Valley glacier:
Description, size, constrained or unconstrained?
Example

A

Confined between valley walls, finishing in a narrow tongue, made from ice caps, sheets or cirques. 3-1500km2. Constrained, Aletsch glacier, Swiss Alps

96
Q

UNIT 2
Piedmont glacier:
Description, size, constrained or unconstrained?
Example

A

Valley Glacier that extends beyond end of a mountain into flat area, spreading out. 3-1000km2. Constrained. Malaspina, Alaska

97
Q

UNIT 2
Cirque glacier:
Description, size, constrained or unconstrained?
Example

A

Occupies a hollow on a mountain side, calves out a corrie. 0.5-0.8 km2. Constrained. Styggebrean Norway

98
Q

UNIT 2
Ice shelf/sea ice:
Description, size, constrained or unconstrained?
Example

A

Large area of floating glacier ice, many glaciers coalesce (fuse). 10-10,000km2. unconstrained. Larsen Ice shelf

99
Q

UNIT 2
What is thermal regime?

A

the temperature of the ice

100
Q

UNIT 2
What are the two types of thermal regimes, and what is the difference?

A

Cold based (polar glaciers) - Glacier is permanently frozen to ground. Average temperature is well bellow 0, surface temperature is -20 to -30. High latitudes.
Warm based (temperate glaciers) - Glacier is not frozen to bedrock. Temperature fluctuates to above melting point, causing meltwater, this is due to the pressure melting point (water melts due to high pressure, even while temperature is below 0 degrees celcius). High altitudes.

101
Q

UNIT 2
Why are glaciers able to move?

A

Glacial ice can deform

102
Q

UNIT 2
What is pressure melting?

A

Ice melts at temperature below 0 degrees, due to pressure of overlying ice.

103
Q

UNIT 2
What is the equation for pressure melting?

A

melting point falls at a rate of 1 degree Celsius for every 100kg/cm3 of pressure

104
Q

UNIT 2
In what thermal regime do glaciers melt. Why?

A

Warm based glaciers reach pressure melting point at depth. Causing meltwater.
Cold based glaciers do not melt as temperature is far from pressure melting point all thought the glacier.

105
Q

UNIT 2
What is Regelation

A

Ice melts under pressure, when pressure is relieved water refreezes

106
Q

UNIT 2
Is Basal sliding warm based or cold based?

A

Warm

107
Q

UNIT 2
What is Basal sliding? This is not a specific type of movement, all warm based glaciers do this.

A

Only occurs when there is meltwater, acting as a lubricant reducing friction, enabling movement.

108
Q

UNIT 2
What is enhanced Basal creep? Cold or warm?

A

Glacier comes into contact with an obstacle. Ice deforms around obstacle, but does NOT reach pressure melting point. Warm based only.

109
Q

UNIT 2
What is the Stoss and Lee side?

A

Stoss - up side
Lee - down side

110
Q

UNIT 2
What is Regelation slip. Cold or warm?

A

f temperature of ice is close to pressure melting point, increased pressure from the stoss side (up movement) of glacier will induce melting. Glacier is able to slip and meltwater flows around obstacle to the Lee side, pressure is reduced and meltwater refreezes - linking to regulation. Warm only.

111
Q

UNIT 2
What is internal deformation. This is not a specific type of movement, all warm and cold based glaciers do this.

A

individual grains of ice withing glacier responding to pressure, this is NOT melting. This is effected with ice thickness and slope angle.

112
Q

UNIT 2
What is intergranular flow? Warm or cold based?

A

Displacement of ice grains relative to one another. Bottom grains are stationary while top rotate clockwise, this is due to slope angle as it is reliant on gravity. A steeper slope angle causes more movement. Warm and cold based.

113
Q

UNIT 2
What is Laminar flow? Warm or cold based?

A

Layers of ice slipping over one another. Ice at the bottom has slower relative velocity then ice at top. This is due to slope angle as it is reliant of gravity. A steeper slope angle causes more movement. Warm and cold based.

114
Q

UNIT 2
What is the deformation of ice called? What is it caused by? Warm or cold?

A

Ice creep. Caused by increased ice thick and/or slope angle. Warm and cold

115
Q

UNIT 2
How does ice deformation cause ice faults, fractures and crevasses.

A

Ice is not able to deform quick enough

116
Q

UNIT 2
Explain extensional and compressing flow.

A

When slope gradient is increased, ice accelerated, causing crevasses. This is extensional flow.
When slope gradient is decreased, ice slows down, causing ice behind to catch up, leading to ice thickening, and crevasses to close. This is compressing flow.

117
Q

UNIT 2
What is subglacial bed deformation? Warm or cold based? What does this cause?

A

Glacier moves over weak, loose rock, causing sediment to deform under weight of glacier. Warm based glacier only.
In Icelandic glaciers this causes 90% of glacial movement

118
Q

UNIT 2
What thermal regime glaciers move faster?

A

Warm

119
Q

UNIT 2
What is the range of movement in a glacier per year?

A

3-300m per year

120
Q

UNIT 2
How does slope angle impact velocity?

A

Higher slope angle = more velocity
vice versa

121
Q

UNIT 2
How does thermal regime impact velocity?

A

Warm based glaciers have more velocity due to
- Water acting as lubricant
- More movement options
- Basal sliding

122
Q

UNIT 2
What are glacial surges?

A

Periods of rapid movements

123
Q

UNIT 2
How much faster can a glacier move in surge conditions?

A

Up to 1000 times faster

124
Q

UNIT 2
What are glacial surges caused by?

A

change of flow pattern of subglacial meltwater

125
Q

UNIT 2
Describe surge conditions

A

Water builds underneath glaciers. Increase of ice in accumulation zone. During winter subglacial meltwater channels are closed, increasing accumulation of ice. During summer ice accumulation is so great that subglacial meltwater channels do not open. Pressure melting point and subglacial meltwater separates basal ice from it’s bed, lubricating it and causing faster velocity. Abundant water increased pore water pressure, adding to movement, Surge occurs and glacier returns to normal flow.

126
Q

UNIT 2
What case study is used for glacial surges

A

Muldrow Glacier, 2021

127
Q

UNIT 2
When did Muldrow Glacier last surge? How far did it move?

A

1956, moving 4 miles

128
Q

UNIT 2
How far did Muldrow Glacier move? How much more is this then normal? What did this cause?

A

200ft in 4 days, 10-20m in one day, 100x faster then normal, caused massive crevasses

129
Q

UNIT 2
Where does Muldrow lie that impacts surge conditions

A

Lies on a fault line, which causes earthquakes

130
Q

UNIT 3
What is weathering?

A

Breakdown of rock, in situ

131
Q

UNIT 3
What are the two processes of weathering

A

Physical processes and chemical processes

132
Q

UNIT 3
What is erosion

A

Removal of rock by ice, water, wind or gravity

133
Q

UNIT 3
What are two types of weathering?

A

Freeze thaw / frost shattering, dilatation

134
Q

UNIT 3
Explain freeze thaw weathering

A

Water enters a crack in a rock, the temperature fluctuates on either side of 0 degrees Celsius. Water freezes and expands by 9% in volume. Putting pressure on rock, after repeated cycles the rock splits

135
Q

UNIT 3
What impacts freeze thaw weathering?

A

Geology of rock (more porous (absorption)/ bedding (gaps in formation)
Climate - temperature must be able to fluctuate between 0 degrees Celsius
Altitude - decrease in temp higher up
Aspect - Orientation of rock, North vs Southern hemisphere

136
Q

UNIT 3
What is an example of freeze thaw?

A

Summit of Glyder Fawr

137
Q

UNIT 3
Explain dilatation

A

Rocks fracture parralell to pressure when the pressure is released (glacier melts). Rocks expand and fracture fue to the pressure release. Called pressure relase or unloading.

138
Q

UNIT 3
What are three erosional processes?

A

Abrasion, Plucking, Sub-glacial meltwater erosion.

139
Q

UNIT 3
Explain abrasion

A

Weathered rocks are embedded as sub glacial debris (under glacier), this scrapes away at rock. Large pieces of rock cause scratches and striations, while fine particles cause smoothing an polishing (like sandpaper). When the debris gets worn away it turns into rock flour.

140
Q

UNIT 3
What are the factors effecting abrasion?

A

Ice thickness - thicker ice causes more erosion due to higher pressure, but too thick and the glacier becomes hard to move
Subglacial meltwater - Increases speed of glacier, but too much lubricant means the glacier will not erode
Relative hardness/resistance of debris and bedrock - if bedrock is harder there will be less erosion, weak debris turns into rock flour
Shape of debris - angular debris causes striations and cracks, fine sand and clay smooth and polish
Supply of debris - More debris causes more erosion, but it depends on the type of debris. Too much causes lower speed
Speed of glacier - Fast movement causes more erosion up to a point - too fast causes less erosion

141
Q

UNIT 3
Explain plucking

A

meltwater seeps into cracks in the rock, it refreezes, when the glacier moves to rock is plucked from the bedrock, causing the entrapment of rocks

142
Q

UNIT 3
What does plucking need to occour?

A

fractures in bedrock, resistant obstacles and meltwater

143
Q

UNIT 3
Plucking also occurs in what movement?

A

Regelation slip

144
Q

UNIT 3
What is sub glacier meltwater erosion?

A

Meltwater channels under glacier, high velocity causes erosion at the glacier’s bed and the widening and deepening of channels

145
Q

UNIT 3
What is an example of sub-glacial meltwater erosion?

A

Gwaun valley, North Pembrokeshire (South Wales)

146
Q

UNIT 3
How does sub-glacial meltwater occour?

A

Increase of meltwater in summer, water flows into cracks and forces rocks out (hydraulic action).
Rocks grind and scrape rock (abrasion)
Ricks bounce around, making them rounder (attrition)
Chemicals in rock release minerals (corrosion)
Lateral erosion and vertical erosion find path of least resistance

147
Q

UNIT 3
Why are sub-glacial meltwater channels powerful?

A

Ice adds pressure, increasing hydrostatic pressure and velocity

148
Q

UNIT 3
Why do sub-glacial meltwater channels have different discharge patterns to normal streams?

A

discharge comes from ablation in winter, movement is based on topography and movement of ice

149
Q

UNIT 3
What is a Macro landform?
What is a meso landform
What is a micro landform

A

Macro - big 1km+
Meso are often found in macro landforms
Micro are the smallest and often a few m

150
Q

UNIT 3
What is a cirque/cwm/corrie
Macro/Meso/Micro?
Case study

A

A large bowl shaped hollow, found at the head of a valley glacier.
Macro
Cwm coch

151
Q

UNIT 3
How many cirques surround the Nant Ffrancon valley? What direction do they face?

A

7, North east

152
Q

UNIT 3
How are cirques/cwm/corrie formed

A

on North facing slopes in winter, small hollows freeze thaw weathering occurs. in summer meltwater removes the debris, enlarging the hollow, called nivation. Firn compacts into ice.

Accumulation results in rotational movement of ice, meltwater from pressure melting adds to this effects, this movement causes stage 2.
Ice rotates, removing fragments from the back wall via plucking, causing a steep, jagged backwall. Rock fragments cause ablation on the hollows floor, deepening the corrie. Crevasses, called bergschrunds add meltwater, causing more rotational movement. Pressure release causes dilation cracks to form, weakening the floor of the glacier, aiding erosion. Glacier begins to moves over the lip of the corrie and out of the rock basin. with abrasion on the stoss side and plucking on the lee side.

153
Q

UNIT 3
What orientations are cirques. Why?

A

Northern hemisphere corries face north east. Receives the least amount of insolation (lower temperatures), meaning firn can form

154
Q

UNIT 3
What is a rose diagram?

A

Circular histogram, showing directional data and frequency

155
Q

UNIT 3
What is a Arete? How are they formed?
Macro/Meso/Micro?
Case study

A

Sharp, knife edge ridge, produced by two corries eroding back to back towards each over (or two glacial troughs).
Macro
Crib Goch - Snowdonia

156
Q

UNIT 3
What does the Gribin Ridge (Arete) separate

A

Two cirques, cwm cneifion and cwm bochlwyd

157
Q

UNIT 3
What is a Pyramidal Peak? How are they formed?
Macro/Meso/Micro?
Case study

A

Three or more corries erode, the remaining central area becomes sharp and steeper due to frost shattering.
Macro
Glyder Fawr - Snowdonia

158
Q

UNIT 3
How tall is Glyder Fawr? What type of weathering occurs at the top because of its height?

A

1001m, freeze thaw weathering

159
Q

UNIT 3
What is a Glacial Trough? How are they formed?
Macro/Meso/Micro?
Case study

A

A U shaped valley, formed when glaciers flow into a pre-existing v shaped river valley. Home to a misfit river
Macro
Nant ffrancon Valley

160
Q

UNIT 3
How long and deep is Nant Ffrancon Valley

A

700m deep and 5km long

161
Q

UNIT 3
What is a Truncated spur? How are they formed?
Macro/Meso/Micro?
Case study

A

steep cliff face in a glacial trough. In a pre existing river valley interlocking spurs occour, as the river erodes the path of least resistance. As the glaicer moves dont the valley these interlocking spurs are eroded.

162
Q

UNIT 3
What landforms also occour in Nant Ffrancon valley?

A

Roche Mountonees, truncated spurs, hanging valleys and misfit river (Afon Ogwen)

163
Q

UNIT 3
What is a Hanging valley? How are they formed?
Macro/Meso/Micro?
Case study

A

A smaller U shaped valley joins a larger glacier. because the small glacier erodes less vertically it is hanging above the larger glacier. May have waterfalls.
Macro

164
Q

UNIT 3
What is a Ribbon lakes? How are they formed?
Macro/Meso/Micro?
Case study

A

Long, narrow lake found in glacial troughs. Glacier moves over alternating band of hard and soft rock. The glacier erodes the softer rock more then the hard rock. The outcrops of hard rock are called rock bars/steps. rainwater accumulates, creating a lake.
Macro
Llyn Ogwen - ribbon lake
Ogwen step - rock step

165
Q

UNIT 3
How is a rock step formed?
Case Study

A

a change in geology, band of hard rock and band of soft rock. Glacier does not erode hard rock but erodes soft rock, causing a drop in altitude.
Ogwen step

166
Q

UNIT 3
How much of a drop is Ogwen step?

A

170m

167
Q

UNIT 3
How long and wide is Llyn Ogwen? How was it formed?

A

1..5km long and 350m wide. Formed by Ogwen glacier

168
Q

UNIT 3
What is a Roche Moutonnees? How are they formed?
Macro/Meso/Micro?
Case study

A

Resistant rock that is smooth on one side and rigid on the other. Formed during regulation slip, with abrasion on the stoss side and plucking on the lee side.
Meso
Pen y Benglog - on Ogwen step

169
Q

UNIT 3
What is a Crag and tail? How are they formed?
Macro/Meso/Micro?
Case study

A

An steep wall of rock followed by a gentle slope. Resistant rock protects softer rock behind it, forming a gently sloping tail on lee side and a steep side, which has plucking and abrasion occur.
Meso
Edinburgh castle

170
Q

UNIT 3
How tall is the Edinburgh Crag and Tail? What type of rock was it made from?

A

130m tall. Igneous rock

171
Q

UNIT 3
What is a Striations? How are they formed?
Macro/Meso/Micro?
Case study

A

long scratches on bedrock, from abrasion
micro
Found on Roche Mountonees in Nant Ffrancon valley

172
Q

UNIT 3
What is a Chatter marks? How are they formed?
Macro/Meso/Micro?
Case study

A

small intermittent chips from abrasion, ice is not in continuous contact with rock.
Micro
Found on Roche Mountonees in Nant Ffrancon valley

173
Q

UNIT 3
What is a polished rock? How are they formed?
Macro/Meso/Micro?
Case study

A

sand, silt and clay (fine particles) polish rock surface, from abrasion.
Micro
Found on Roche Mountonees in Nant Ffrancon valley

174
Q
A

Geography Edquadus (4 decks)

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