Glacial Systems and Processes Flashcards
(111 cards)
1
Q
What is accumulation?
A
Accumulation: The addition of mass
(precipitation, usually snow) to the glacier.
Mainly occurs at higher altitudes at the
source of the glacier
2
Q
What is ablation?
A
Ablation: The loss of mass from the glacier.
This includes meltwater, avalanches,
sublimation, evaporation, and other
processes.
3
Q
What is the glacial budget?
A
Glacial budget: The mass balance of a glacier, i.e the difference between accumulation and
ablation.
4
Q
What is a positive glacial budget?
A
A positive glacial budget shows accumulation exceeds ablation , so the glacier is
advancing.
5
Q
What is a negative glacial budget?
A
A negative glacial budget shows ablation exceeds accumulation , to the glacier is
retreating.
6
Q
How do glacial budgets fluctuate?
A
Glacial budgets fluctuate yearly, with more ablation in the summer months and more accumulation
in winter months.
7
Q
How are glaciers natural systems?
A
Glaciers are natural systems, meaning there are specific interactions
within their development and sustaining that allow glaciers to work.
8
Q
How do open systems work?
A
In an open system, there are inputs from outside the system’s set area
9
Q
How does a close system work?
A
In a closed system, all of the inputs and processes occur within the
system’s set area
10
Q
What are the inputs into a glacier?
A
Additions to the glacier
(accumulation). Precipitation such as
snow or hail are inputs to the glacier, as well
as avalanches from other areas entering the
system.
Debris that has been eroded can
also fall into a glacier’s system and
consequently can be transported and
deposited elsewhere.
11
Q
What are the stores in the glacial system?
A
Also known as components.
Stores are the mass that glaciers hold.
The majority of stores within the glacier are
ice, but sediment from erosion and meltwater
lakes/channels also contribute to stores.
There are 3 types of glacial stores:
subglacial (underneath the glacier),
englacial (within the glacier), and
supraglacial (on top of the glacier)
12
Q
What are the outputs of the glacial system?
A
Things that leave the
glacier system, usually in the form of
meltwater. All ablation processes are
outputs. Calving is also a common output, in
which large pieces of glacier break off at the
snout (the end).
13
Q
What are the flows in the glacial system?
A
Flows occur in glaciers through the
transfer of mass or energy. There are
flows in mass and energy from ice on the
glacier to meltwater leaving the glacier. The
glacier also moves through flows, such as
compressional flow.
14
Q
Describe the energy in glacial systems
A
Glaciers all have varying
amounts of energy dependent on their
mass, their environment, their composition
and other factors. For example, a glacier with
more meltwater underneath it would move
faster, giving it more energy. Glacial energy
is usually in the form of kinetic energy as the
glacier moves. This energy allows erosion to
occur. Gravity allows the glacier to have
energy, as it forces the glacier downhill.
15
Q
What is dynamic equilibrium and how does it work within glacial systems?
A
Equilibrium refers to a state of balance. This balance is dynamic when the processes causing the balance are continual (always occuring). For example, even if the glacier is constantly gaining inputs and losing outputs, if the amount of these are the same, the mass of the glacier does not change annually and the glacier is at dynamic equilibrium. The area where mass gain = mass loss on a glacier is called the equilibrium line.
16
Q
What is a feedback loop?
A
Feedback Loops: A feedback loop is a type of chain reaction, where one process leads to
another process, leading to another process, and so on. There are two types of feedback loops:
positive and negative.
17
Q
Describe the positive feedback loop in a glacial system
A
In positive feedback, a process occurs, which causes another
process to occur, which starts a chain reaction that heightens the
first process.
1. Temperatures rise - 2. Permafrost melts - 3. Greenhouse effect - 4. CO2 released
18
Q
Describe the negative feedback loop in a glacial system.
A
In negative feedback, the process that occurs is counteracted
by an opposing process, causing the effects to cancel each other
out and nothing to change.
1. Temperatures rise -2.Permafrost melts- 3.More plants to take in CO2- 4.Greenhouse effect lessens
-5.Temperatures fall
19
Q
Describe the distribution of polar environments
A
Polar environments are located at the poles (high latitudes) of the Earth within the Arctic Circle
(66°N) and the Antarctic Circle (66°S) .
20
Q
Describe the conditions of polar environments
A
These environments can also be described as being within
the 10°C isotherm, which means in the hottest month, the average temperature stays below 10°C.
However, the first definition is the most common.
In polar regions, the maximum extent of ice sheets occurs within the coldest, winter months. The
Arctic Winter (northern hemisphere) occurs from December - March, and the Antarctic Winter
(southern hemisphere) occurs from March - October.
21
Q
Why is the soil in polar environments deprived of nutrients?
A
Due to the consistently below freezing temperatures with little rainfall, polar environments have slow nutrient cycles, meaning the soil is usually deprived of nutrients.
22
Q
What are the winter temperatures and precipitation levels? Polar
A
.Winter temperatures average -40°C in some polar regions and precipitation almost never exceeds 100mm per year.
23
Q
Describe the vegetation in polar regions
A
The cold, harsh climate with little rainfall also means only highly adapted vegetation can grow, such as mosses and lichen. These plants rarely decompose as there are a
lack of decomposers. When plants eventually decompose, the cold temperatures cause this process to be extremely slow.
24
Q
Describe the soil in polar regions
A
This lack of nutrient rich vegetation from the harsh climate causes the soil to be low in nutrients. The nutrient deprived, frozen soil further limits nutrient rich plant growth. This creates a cycle where poor vegetation causes poor soil, and poor soil causes poor vegetation.
25
What is the distribution of alpine environments?
Alpine environments are areas of low temperatures in high altitude, mountainous regions, found
at any latitudes. These environments are found above the tree line.
26
What are the temperatures in the alpine environments like?
Temperatures in alpine areas fluctuate annually, and alpine summers are frequently above 0°C.
An example of an alpine environment is Mount Washington, The White Mountains. There is a large amount of fluctuation between seasonal temperatures, January -20 low, -10 high and in July 8 low, 12 high.
27
Describe the weather/climate conditions in the winter in alpine environments
```
In the winter, alpine
environments receive
heavy snowfall, more than
in polar environments in
most cases. In summer,
milder temperatures can
lead to sometimes heavy
rainfall and a lot of
meltwater from the melting
of snow and ice. The
climate allows adapted
animals to move to higher
altitudes. The milder
temperatures also stimulate
plant growth, thawing, and
decomposition.
```
28
Describe the vegetation in the alpine environments
```
Vegetation that is adapted
to the alpine climate
thrives in milder alpine
summers, and usually dies
back in winter. The climate
(and consequent wildlife)
allows for a quicker
nutrient cycle, as the
wildlife use vegetation for
food and the warmer
climate encourages
decomposing. Alpine
vegetation is decomposed
more quickly than in a
polar climate, and grows
quicker too due to soil
fertility and climate.
```
29
Describe the soil in alpine environments?
```
Higher temperatures allow
soils (usually at lower
altitudes) to thaw,
increasing the area that
vegetation can grow in.
The nutrient rich vegetation
allows a more fertile soil to
develop when it
decomposes, as the
nutrients are transferred
into the soil. This fertile soil
allows more nutrient rich
plants to grow. Soils
usually freeze in winter,
meaning less plants can
grow in the colder
conditions.
```
30
Describe the distribution of periglacial environments.
Periglacial environments are areas found on the edge of colder environments like polar and alpine
environments.These areas are consistently cold enough that the ground is permanently frozen
(permafrost). Permafrost can be continuous, discontinuous, sporadic or isolated, which
indicates the extent of permafrost cover. Although permafrost is also found on the fringes of glacial
and alpine environments, the majority of permafrost is located at high latitudes within the
northern hemisphere
31
Describe the weather/climate conditions in periglacial areas
```
Similar to polar
environments,
precipitation is low (but
still occurs in summer
months). Temperatures are
consistently below
freezing. The latitude of
some permafrost regions
also assists in the
consistently cold
temperatures, as winters in
higher latitudes last longer
with less daylight hours,
making them colder.
```
32
Describe the vegetation in periglacial environments
```
Vegetation is more
prevalent than in polar
regions, but only highly
adapted plants can survive
in the cold temperatures
with little rainfall. The
temperatures and poor soil
leads to a slow nutrient
cycle.The lack of nutrient
rich plants contributes to
the soil infertility. The
permafrost makes it
especially hard for plants to
grow as plants cannot
infiltrate the soil.
```
33
Describe the soil in periglacial environments
```
The cold climate causes the
lower ground to be frozen
all year around. However,
slightly warmer summer
temperatures causes the
thawing of upper soil called
the active layer. Soil is
usually extremely
waterlogged in summer
due to thawing, which
means plants become
deoxygenated within the
soil and cannot survive, and
any nutrients are often
leached out.
```
34
What are glacial environments?
A glacial environment is an area where temperatures are consistently cold enough to sustain
glaciers or ice sheets. Glacial environments are in both polar and alpine areas (and sometimes
periglacial however temperatures are usually not cold enough). The climate, soil, and vegetation is
dependent on the region in which the glacier develops, but the temperatures must be below
freezing for long enough in the year that the glacier does not melt entirely.
35
When was the most recent major ice age?
Aside from an ice age around 300 million years ago, the most recent major ice age
occured in the Pleistocene era. The period spanned from around 2.5 million years ago
to 11,700 years ago.
During this ice age, there were many fluctuations in global temperatures:
● Glacial period: colder temperatures, causing glacial advances and sea levels to fall.
● Interglacial period: warmer temperatures, causing glacial retreats and sea levels to rise.
36
What were global temperatures in the most recent ice age/
During this ice age, there were many fluctuations in global temperatures:
● Glacial period: colder temperatures, causing glacial advances and sea levels to fall.
● Interglacial period: warmer temperatures, causing glacial retreats and sea levels to rise.
37
When was the most recent period of glacial advance?
The most recent period of glacial advance ( Last Glacial Maximum ) was around 21,000 years
ago, and the present distribution of cold environments is much more isolated in comparison to this
period.
38
What period is the world currently in and how are glaciers affected?
The world is currently in an interglacial period, meaning temperatures are higher and the majority
of our glaciers are retreating.
39
How has the movement of glaciers occured?
```
Glaciers have advanced
and retreated in
correlation with the
world’s glacial and
interglacial periods.
```
40
Describe the current global temperatures and the reason for this.
Historically, global temperatures have been
increasing since Last Glacial Maximum. However,
there have been smaller global coolings in
recent history that have affected the mass
balance of glaciers.
41
Which period in recent history has the most significant global cooling?
The ‘Little Ice Age ’ -
between 1300 and 1870 has been the most
significant global cooling in recent history. The
graph shows the length change in 5 different
glaciers in Mont Blanc in history. The period from
1818-1821 (during the Little Ice Age) shows that
all glaciers were at their largest point at this time.
42
Describe the glacial advance of the Alps during the Little Ice Age.
Glacial advance in the Alps was a very prevalent
issue during the Little Ice Age. Heavy snowfall
and avalanches were common and posed a risk
to life.
“Between 1627 and 1633 Chamonix lost a third if
its land through avalanches, snow, glaciers and
flooding, and the remaining hectares were under
constant threat. (Source: Fagan, 2010.
43
What are the two types of glacier?
There are two main types of glaciers that develop in glacial environments - warm based and cold
based glaciers. Each glacier type has a specific development and certain characteristics.
44
Describe warm based glaciers, environment, climate, features and processes.
Environment: Alpine
Climate: Fluctuating, warmer temperatures
Features: Lots of meltwater
Processes: High erosion from basal sliding,
internal deformation also present
45
What is the average surface temperature of warm based glaciers in the summer and winter?
Summer≈5°c (above freezing)
Winter≈-10°c. Large range between
seasons.
46
What is the average base temperature of warm based glaciers in the summer and winter?
Summer: Just below 0°c (melting as it reaches PMP*)
Winter: Below 0°c. Less meltwater but still present.
47
Describe cold based glaciers, environment, climate, features and processes.
Environment: Polar
Climate: Consistently dry and cold
Features: Very little meltwater
Processes: Internal deformation only, very little basal sliding
48
What is the average surface temperature of cold based glaciers in the summer and winter?
Summer≈ -15°c or colder.
Winter≈ -20 to -30°c.
49
What is the average base temperature of cold based glaciers in the summer and winter?
Summer≈ -10°c or colder. Way below PMP*.
| Winter≈ -10°c or colder. Little change compared to summer.
50
What is the pressure melting point, and explain it.
```
*Pressure melting point (PMP): The temperature at which ice melts under pressure. Deeper =
more mass weighing down on base = more pressure on base = more friction = lower pressure
melting point (so ice melts before 0°C).
```
51
What are the main processes which form glaciated landscapes?
The three main type of
processes that create landforms are geomorphological (topography/rocks), periglacial, and
fluvioglacial (water). These processes create glaciated, periglacial, and fluvioglacial landscapes.
52
What are the three types of glaciated landscapes?
Glaciated, periglacial, and fluvioglacial landscapes.
53
What are the two types of glacial erosion?
Plucking: Rocks attached to bedrock or sides become frozen to the glacier. When
the glacier moves, the rocks are pulled ( plucked) from the landscape, leaving a
jagged surface.
○ Abrasion: A sandpapering effect caused by small rocks embedded within the
glacier rubbing on bedrock. Usually leaves a smooth surface with scratches called
striations.
54
What is abrasion?
Type of erosion that has a sandpapering effect caused by small rocks embedded within the
glacier rubbing on bedrock. Usually leaves a smooth surface with scratches called
striations.
55
What is plucking?
Type of erosion where Rocks attached to bedrock or sides become frozen to the glacier. When
the glacier moves, the rocks are pulled ( plucked) from the landscape, leaving a
jagged surface.
56
What are the types of glacial weathering?
Frost Action: Water gets into the cracks of rocks, freezes and then expands by
around 10%. This repeated action puts pressure on a rock, eventually causing it to
shatter and break off.
○ Nivation: Common in periglacial environments due to the fluctuating temperatures.
Nivation is a collective term for processes involving snow and ice that cause
erosion (the prefix niv- is Latin for snow). Nivation hollows are created by nivation
processes, which is where snow gathers in a small depression and eventually this
erodes into a hollow full of snow. Nivation hollows are the beginnings of corries.
57
What is frost action?
Type of weathering where Water gets into the cracks of rocks, freezes and then expands by
around 10%. This repeated action puts pressure on a rock, eventually causing it to
shatter and break off.
58
What is nivation?
Type of weathering which Common in periglacial environments due to the fluctuating temperatures.
Nivation is a collective term for processes involving snow and ice that cause
erosion (the prefix niv- is Latin for snow). Nivation hollows are created by nivation
processes, which is where snow gathers in a small depression and eventually this
erodes into a hollow full of snow. Nivation hollows are the beginnings of corries.
59
What are the types of glacial movement?
○ Internal Deformation: The deformation of layers of ice or individual ice crystals
caused by the pressure from the weight of the ice. This causes some layers to
move faster than others, so different parts of the glacier can be further advanced.
○ Compressional Flow: When ice hits a shallower gradient, friction causes the ice to
slow down, build up and compress. This causes ice to get thicker.
○ Extensional Flow: When ice meets a steep downhill gradient (usually when going
over a hill), gravity forces the ice to increase in velocity. Friction causes the ice to
thin out and extend, causing deep cracks called crevasses.
○ Rotational Slip: Compressed ice becomes trapped in a hollow, but gravity causes
it to continue to move downwards. Meltwater assists in moving the glacier in a
rotational movement, causing it to continually erode the hollow.
○ Basal Sliding: Glacier sliding over the bedrock. This is due to meltwater providing
lubrication for the glacier to move.
60
What is internal deformation?
A type of glacial movement where The deformation of layers of ice or individual ice crystals
caused by the pressure from the weight of the ice. This causes some layers to
move faster than others, so different parts of the glacier can be further advanced.
61
What is compressional flow?
A type of glacial movement When ice hits a shallower gradient, friction causes the ice to
slow down, build up and compress. This causes ice to get thicker.
62
What is extensional flow ?
A type of glacial movement When ice meets a steep downhill gradient (usually when going
over a hill), gravity forces the ice to increase in velocity. Friction causes the ice to
thin out and extend, causing deep cracks called crevasses.
63
What is rotational slip?
A type of glacial movement where compressed ice becomes trapped in a hollow, but gravity causes
it to continue to move downwards. Meltwater assists in moving the glacier in a
rotational movement, causing it to continually erode the hollow.
64
What is basal sliding?
A type of glacial movement where the glacier sliding over the bedrock. This is due to meltwater providing
lubrication for the glacier to move.
Pressure builds, glacier melts, meltwater lubricates glacier, pressure is alleviated.
65
What factors affect the extent/rate of glacial movement?
● Temperature of glacial environment - warmer temperatures would lead to more
meltwater, causing more basal sliding to occur. Erosional processes would thus be
heightened.
● Mass of glacier - heavier glaciers move more under the force of gravity, and more
pressure is created due to the weight. In itself, this pressure causes erosional processes,
but also encourages meltwater which assists in erosion.
● Relief - a steeper relief heightens the effects of gravity on a glacier. A warm based
glacier would have a higher velocity as meltwater assists lubrication. A cold based
glacier would struggle to move, building pressure and again causing more erosional
processes. This could be classed as a negative feedback loop.
66
How does the temperature of the glacial environment affect the rate of movement?
● Temperature of glacial environment - warmer temperatures would lead to more
meltwater, causing more basal sliding to occur. Erosional processes would thus be
heightened.
67
How does the mass of the glacial environment affect the rate of movement?
Mass of glacier - heavier glaciers move more under the force of gravity, and more
pressure is created due to the weight. In itself, this pressure causes erosional processes,
but also encourages meltwater which assists in erosion.
68
How does the relief of the glacial environment affect the rate of movement?
Relief - a steeper relief heightens the effects of gravity on a glacier. A warm based
glacier would have a higher velocity as meltwater assists lubrication. A cold based
glacier would struggle to move, building pressure and again causing more erosional
processes. This could be classed as a negative feedback loop.
69
What are the periglacial processes?
Active Layer: The top layer of permafrost that thaws in the summer.
○ Frost Heave: Water underneath rocks or ground freezes, expands, and thus forces
the mass upwards.
○ Solifluction: Mass movement of soil that becomes waterlogged when water is
trapped between the active layer and the frozen permafrost. Waterlogged soil flows
easily when gravity acts upon it (usually on a gradient).
70
What is the process of the active layer?
Periglacial process, the top layer of permafrost that thaws in the summer.
71
What is the process of frost heave?
Periglacial process, water underneath rocks or ground freezes, expands, and thus forces
the mass upwards.
72
What is the process of solifluction?
Periglacial process, mass movement of soil that becomes waterlogged when water is
trapped between the active layer and the frozen permafrost. Waterlogged soil flows
easily when gravity acts upon it (usually on a gradient).
73
What landforms are created by geomorphic processes of erosion?
```
Corries
Aretes
Glacial troughs
Hanging valleys
Truncated spurs
Roches moutonnées
```
74
What landforms are created by geomorphic processes of deposition?
Drumlins
Erratics
Morraines
Till Plains
75
What landforms are formed by fluvioglacial processes?
Meltwater channels
Kames
Eskers
Outwash plains
76
What landforms are formed by periglacial processes?
```
Patterned ground
Ice wedges
Pingos
Blockfields
Solifluction lobes
Terracettes
Thermokarst
```
77
How are corries formed? Provide an example
Corries form when snow continues to build
up in a depression or nivation hollow,
eventually compacting to form a glacier. The
glacier becomes trapped within the hollow,
meaning the only way it can move is through
rotational slip. The back wall is eroded
through plucking and frost shattering, and the
hollow is deepened through rotational
abrasion. Water can fill corries to make tarns
(lakes).
As corries are eroded rocks, they last a long
time and are minimally affected by erosion.
This is why corries have lasted thousands of
years.
Erosional
Red Tarn, Lake District
78
What is an arete? Provide an example
A knife-edged ridge formed between two
corries (when the two steep back walls
meet). If three meet, they create a point
called a pyramidal peak.
Erosional
```
Striding Edge (Helvellyn), The Lake
District.
```
79
What is a pyramidal peak? Provide an example
A knife-edged ridge formed between two
corries (when the two steep back walls
meet). If three meet, they create a point
called a pyramidal peak.
Erosional
80
How is a glacial trough formed? Provide an example
A u-shaped valley formed by a glacier
bulldozing and eroding through a river
(v-shaped) valley. The glacier has enough
force to erode away a river’s interlocking
spurs. This leaves smooth but steep
truncated spurs on the valley sides and a
wide, flat valley floor. The river that originally
flowed through the valley will continue to flow,
giving it the name misfit stream due to its
small size in comparison to the surroundings.
U shaped valleys last for a long amount of
time.
Erosional
Glen Geusachan, The Cairngorms
81
How is a hanging valley formed? Provide an example
```
A smaller u-shaped valley caused by a
tributary glacier. The smaller glacier does
not have enough energy to erode to the
valley floor, leaving a hanging valley.
Waterfalls often form here.
```
Hanging valleys last for a long time as they
are an erosional feature, however waterfalls
can erode away a hanging valley over
time.
Erosional
Fiordland National Park, New Zealand
82
How are roches moutonnees formed? Provide an example
A mound of rock shaped by a glacier flowing over it and eroding it. The glacier would be moving
right (stoss side) to left (lee side) in the picture.
● The glacier hits an obstacle that is too large and hard to pluck, it must move over it.
● The glacier hitting the obstacle increases friction and pressure, therefore increasing
melting as the lower ice can reach the pressure melting point.
● This meltwater allows the glacier to slide over the rock, and smaller rocks will abrade the
stoss side
● When the glacier reaches the top of the obstacle, friction and pressure drop
● Meltwater refreezes
● Frozen rocks are plucked from the lee side.
These landforms last a long time as they are made of rock.
Erosional
Myot Hill, Falkirk, Scotland
83
What are till plains and how are they formed? Provide an example
Till is unsorted glacial material formed
through erosion and weathering. Till plains
form when an ice sheet detaches from the
main glacier and melts, causing all of the till
on top of and within the glacier to deposit
on the valley floor.
```
Till plains last a medium-long amount of
time. They can be disrupted through
meltwater, periglacial processes and
weathering. However, due to their vast
nature, till plains will usually be noticeable.
```
Depositional
Saskatchewan Glacier, Alberta
84
What are erratics and how are they formed? Provide and example
A large boulder that is of a different rock
type to surrounding rock. This boulder
would have been broken off by weathering
and erosion, then transported by a glacier
and deposited when it has been moved to
a different location. The glacier deposits
when it loses energy.
Depending on the size of the erratic, these
can last a long time as they are too big to
be displaced by weathering alone.
Depositional
Norber Erratics, Yorkshire Dales
85
What are morraines? Provide an example
Deposits of eroded material that are
transported with the glacier. There are
different types of moraine:
Lateral: material deposited on the sides of
a glacier, leaving a ridge when the ice melts.
Medial: formed from two lateral moraines
meeting in the middle of a glacier and
depositing material.
Ground: carried under the glacier and
abraded between the glacier and valley
floor. Ground moraine is the only sorted
moraine as all of it is abraded underneath
the glacier, whereas all other types of
moraine is unsorted.
Recessional: Forms at the end of a glacierwhen a retreating glacier stays stationary
for a sufficient time. Usually shows smaller,
seasonal retreats.
Terminal: Material deposited at the snout of
a glacier on the valley floor.
Moraine can be classed as lasting a
medium amount of time. Although moraine
is still present thousands of years after
glaciers have retreated, it can be displaced
through meltwater during retreat or
weathering.
Depositional
Wrangell-St. Elias, Alaska
86
What are drumlins and how are they formed? Provide an example
```
When a glacier hits an obstacle that
cannot be eroded, deposition from
underneath the glacier builds up behind
the obstacle. The glacier moves over the
large mound and then drags excess
deposition over the other side. This causes
a tear drop shape with a long, tapered
edge. The blunt end is the stoss side,
whereas the tapered end is the lee side.
Drumlins can be around 1500m long and
100m high. Drumlins are usually found in
groups called ‘swarms’.
```
Drumlins last a long time, but can
sometimes be disguised as they are
depositional, meaning greenery can grow in
the sediment.
Depositional
Eureka Drumlin Field, Montana
87
What is a meltwater channel and how are they formed? Provide an example
Streams of meltwater (melted glacier) formed
by higher temperatures. Channels can flow
within, in front of, and around the glacier. Due
to the pressure from the glacier, they are
highly erosive. If meltwater channels lose
energy, they deposit sorted material in small
islands, creating braided channels.
Meltwater channels last a short amount of
time because they will only last during
periods of higher temperatures that will allow
for liquid water. However, the eroded landscapes can last a long time
Fluvioglacial landform
Ellesmere Island, Canada
88
What is a kame and how are they formed? Provide an example
Meltwater transports and deposits eroded
material on a retreating glacier. Material
collects within a depression on top of the
glacier. When the glacier melts completely,
the material is left on the valley floor. This
leaves a mound of (usually fine) material.
Kames are sorted, meaning the heaviest
load will be deposited first and finer
sediments will be on top.
Kames last a medium amount of time as
they can be eroded and weathered due to
their composition.
Fluvioglacial landscape
Kirriemuir, Scotland
89
What are eskers and how are they formed? Provide an example
A long, winding ridge of glacial deposition.
An esker is a mould of glacial meltwater
channels. Material is deposited when the
subglacial meltwater channel loses energy.
Due to the high hydrostatic pressure, the
mound builds up and retains its shape.
Eskers last a medium-long amount of time.
Due to their size, an esker is difficult to erode
and weather, however it is not as strong as
erosional, rock-composed features.
Fluvioglacial landscape
The Kippet Hills Esker, Aberdeenshire
90
What is an outwash plain and how are they formed? Provide an example
When a glacier recedes, a large amount of
meltwater is released due to the higher
temperatures melting the ice. The meltwater
loses energy as it is under less pressure, so
it deposits the material in front of the
glacier. Material is deposited into sorted
layers - gravel and rocks are deposited first
and the finer sediment is deposited on top.
The deposits can create alluvial fans, which
is where the meltwater channels separate
into smaller, fanned out sections in order to
take the fastest route through the deposited
material.
These plains last a short amount of time as
they are only sediment, meaning they are
easily eroded and weathered. In alpine
regions especially, outwash plains are only
seasonal.
Fluvioglacial landscape
Rendu Glacier, Alaska
91
What is patterned ground and how is it formed? Provide an example
```
Patterned ground is formed through the frost
heave of stones in and underneath the active
layer.
● Ice lenses exist within permafrost,
and they grow through repeated
freezing and thawing. Capillary
action draws more water to the ice
lens, causing it to grow more.
● When the ice lens expands, stones
around the ice lens are shunted
upwards.
● Larger stones roll down due to their
weight.
● Fine sediment fills the space to
stop larger rocks.
● Polygons appear on flat surfaces, or
stripes on steeper inclines where
the rocks roll downhill.
```
This landform lasts a medium amount of
time as they can be disrupted when
periglacial landscapes become warmer,
disrupting the ice lenses.
Periglacial
‘Stone Rings’, Svalbard
92
What are ice wedges and how are they formed? Provide an example
```
Water infiltrates small cracks in the
permafrost and expands on freezing (frost
action). Water then fills the expanded
ground. The process repeats and leaves a
large ice wedge.
```
The ice wedge is likely to last a medium
amount of time as temperatures must
consistently stay cool enough for the ice
wedge to grow.
Periglacial
Banks Island, Canada
93
What are pingos and how are they formed? Provide an example
```
Ground is forced upwards through frost
heave of an ice lens, leaving a mound. The
mound can be an open or closed pingo.
Open pingo formation (discontinuous
permafrost)
● Water moves through unfrozen
ground between areas of permafrost
● Due to capillary action, the water
groups together
● Water freezes and creates an ice lens
● The ice lens continues to grow and
pushes the unfrozen ground upwards
Closed pingo formation (continuous
permafrost)
● Under a lake, permafrost is
insulated and melts.
● The lake will eventually dry up or
freeze, leaving the unfrozen ground.
● An ice lens will develop through
capillary action when temperatures
drop and the water groups together
● When temperatures drop, permafrost
advances and frost heaves the
unfrozen ground upwards, creating a
mound.
```
Pingos last a medium amount of time, as
cracks in the ground let in water which melts
the ice lens, and warmer temperatures also
melt the ice lens.
Periglacial
Pingo National Landmark, Canada
94
What are terracettes and how are they formed? Provide an example
.The formation of terracettes is not wholly
known or agreed upon in geographical study.
There are a few theories as to how they
arise, however the most common theory
involved the intervention of vegetation. Frost
heave pushes particles of soil upwards,
which would usually fall downhill through the
process of creep. However, vegetation
blocks the soil from falling, meaning it stays
behind in a step shape. The shape of
terracettes can be described as terraces.
Terracettes last a short-medium amount of
time as thawing of the soil would disrupt the
process of frost heave. However, the extent
of the landform means the area is unlikely to
be cleared completely in the short-term through weathering
Periglacial
Kingston near Lewes, The South
Downs
95
What are solifluction lobes? Provide an example
When the active layer thaws and solifluction
occurs, tongue-shaped lobes of soil fall down
a slope.
Solifluction lobes last a short-medium
amount of time, as the soil cannot retain the
stretched structure for long, and when
temperatures rise the soil moisture content
will decrease.
Periglacial
Seward Peninsula, Alaska
96
What are blockfields? Provide an example
A rock-strewn landscape caused by
extensive frost action of the landscape
Blockfields will last a medium-long amount
of time as loose rocks can be displaced
through weathering.
Periglacial
Broad Crag, The Lake District
97
What is thermokarst? Provide an example
Marshy, boggy wetlands caused when permafrost melts. Any ice lenses within the ground
originally, or landforms such as pingos would melt and collapse. This can leave holes in the
ground, which will also fill with meltwater.
Thermokarst landscapes last a short-medium amount of time as they will dry up when
temperatures rise and permafrost retreats
Periglacial
Hudson Bay Lowlands, Canada
98
Define environmental fragility
Environmental Fragility: The concept of an environment being vulnerable and at risk , as it lacks
the ability to be resilient and adapt to changes.
99
Why are cold environments considered to be fragile?
Highly adapted ecosystem - plants and animals must be highly adapted to the extreme weather
conditions around them in order to survive. Especially in polar regions, plants and animals have
adaptations that allow them to survive in the cold temperatures . Therefore, when something in
the ecosystem changes, e.g. the temperature becomes higher, these highly adapted species find it
more difficult to cope with the changes.
Slow nutrient cycle - due to the cold temperatures and nutrient deprived environment, cold
environments’ nutrient cycles are slow. This means that things will take longer to break down,
and longer to restore if they are damaged. Plants cannot regenerate as quickly as in other
environments, which can limit their growth indefinitely. This also means that if litter or other foreign
objects are placed in the environment, they will take a long time to decompose which can affect
plant and animal behaviour.
Lack of biodiversity - due to the cold and unforgiving climate, only certain plants and animals
thrive, meaning food chains are limited and species depend on each other. If a species is
removed or damaged, this can spread throughout the entire food chain, affecting every aspect of
the ecosystem. For example, species of krill is declining in the Antarctic, which is causing penguins
to migrate to different areas, affecting seal populations.
100
How do humans impact fragile cold environments?
Humans affect cold
environments through direct intervention or through a passive contribution.
Tourism
Resource exploitation
Fishing and whaling
Pollution
101
How does tourism impact fragile cold environments?
Tourism is a recent but present problem in cold environments. Alpine
tourism is the most prevalent and oldest form of cold environment
tourism due to mountainous regions being used as ski slopes.
● The development of ski resorts increases urbanisation and
construction, displacing wildlife and the ecosystem
● Humans in alpine areas disrupt the ecosystem by destroying plants in snow sports and
scaring wildlife away (e.g. the environmental damage caused by ski runs is likely to be
irreparable -plants will not recover during thawing season)
● Any litter dropped will stay in the nutrient cycle for a long time, as decomposition is slow
26,435 Antartic tourists in 2006, 6704 in 1992/3
Tourism in other cold environments is also a growing industry, especially in Antarctica due to a
recent rise in ‘ extreme tourism’. Antarctica is arguably even more fragile than alpine
environments, meaning any foreign object entering the ecosystem is likely to have catastrophic
effects on the pristine and untouched environment. Sea ice destruction and cruise ship crashes
are also contributors to environmental destruction as tourist numbers increase. For example, the MS explorer crash in 2007
102
How does resource exploitation impact fragile cold environments?
Polar and periglacial environments especially have an abundance of natural resources, such as
minerals and oil. These regions have therefore become at risk of overexploitation and habitat
destruction.
● Oil exploitation disrupts the habitat through the infrastructure that comes with it, e.g.
drilling and pipelines.
● Oil spills also cause catastrophic damage to periglacial and polar regions, as the fragile
ecosystem cannot remove the oil quickly, affecting the ecosystem. As seen in Alaska in 2006
Metal and mineral exploitation damages the environment through mining and quarrying,
scaring away wildlife and causing damage beyond repair. Currently, Antarctica is protected
from this exploitation, but this is not to say it will be in the future.
● Scientific research is also a threat as scientific tests can disrupt the environment, although
research is usually carried out sustainably.
103
How does fishing impact fragile cold environments?
```
Polar regions especially are
under threat from
unsustainable fishing in
these areas, which disrupts the
food chain of these fragile
environments. Sealing and
whaling began as far back as
the 18th century, and although
there are currently bans on
almost all whaling, whale
populations still stay at reduced
and endangered levels from
the damage previously done in
the past.
```
```
Other fishing has increased in
the 20th and 21st century, and
there are still reports of illegal,
unreported, and unregulated
(IUU) fishing. This fishing is
unsustainable and causes
wide scale marine habitat
damage. Overfishing also
removes vital animals in the
food chain, such as overfishing
of krill which removes other
marine animal food sources.
```
104
How does pollution impact fragile cold environments?
Pollution is the largest scale problem impacting cold environments. There is local pollution issues
associated with leaving litter etc. in alpine environments and polluting an area with oil. However,
pollution is also a global issue due to the combustion of fossil fuels.
The combustion of fossil fuels causes a variety of issues for cold environments, often setting up
positive feedback loops in which an impact can quickly spiral into a worse impact. Global
warming is a major issue for cold environments.
● Warmer temperatures cause melting, which is clearly bad for all cold environments.
www.pmt.education
○ Permafrost melts
○ Glaciers retreat
○ Alpine environments thaw for longer summers
This melting causes further issues:
■ Local floods near glaciers
■ Regional floods if rivers etc. carry water elsewhere
■ Global floods if major ice sheets and glaciers melt, causing sea level rises
■ Disruption to flora and fauna that are adapted to the environment
■ CO2 is released into the atmosphere that is stored in ice sheets and
permafrost
■ Albedo effect is lessened due to less ice sheets (this is the idea that white
surfaces - ice - reflect solar radiation back into the atmosphere, meaning
more heat is absorbed into oceans)
```
Positive feedback loop from melting:
Carbon dioxide released,
Greenhouse effect,
Ice sheets melt permafrost (releases more co2),
Ocean absorbs more heat,
Sea temp rises,
More ice sheets melt
```
105
How do higher regional temperatures affect wildlife?
Higher regional temperatures affect cold environments in other ways
○ Invasive species that are adapted to higher temperatures have grown and caused
the colonisation of some cold environments
○ Migration patterns of certain animals have been disrupted by the higher
temperatures. For example, the strandings of polar bears migrating to lower
latitudes in winter
■ Food chains are disrupted by migration changes and invasive species
106
How is tourism being managed to reduce the effect on fragile cold environments?
Sustainable tourism is becoming a growing industry, helping to reduce the effects humans have
on their trips to fragile cold environments. Charities such as WWF are promoting sustainable alpine
tourism in order to protect these areas. Visit their website for examples of ‘green tourism’ in alpine
environments
Polar extreme tourism in most cases encourages a positive management of these cold
environments. Visitors are limited so only smaller cruise ships can land (100 people at a time).
Cruise ships must also have a permit and regulations are very tight . For example, shoes must be
checked for foreign objects so they do not enter the ecosystem. Tourists are also encouraged to
become aware of the risks to cold environments and contribute to charities.
Cold environments are also protected by law in some areas, such as areas of permafrost in
Alaska that restrict access and construction.
107
How is resource exploitation being managed to reduce the impact on fragile cold environments?
Many cold environments are protected by law so that any natural resources cannot be over
exploited. For example, the Antarctic Treaty and Madrid Protocol have banned mining in
Antarctica. There are also extensive fishing quotas and monitoring systems in polar
environments as to protect the ecosystem, as well as a ban on all military activity.
108
How is climate change being managed to reduce the impact on fragile cold environments?
There is little that can be done directly to stop the effects of climate change on cold environments.
Globally, though, there are strategies in place to mitigate climate change so that it may not have
such catastrophic effects.
```
Paris Climate Deal (COP21):
- Aim to limit global
temperatures to 2°C above
pre-industrial levels
- Support for developing
countries
- Public interaction and
awareness schemes
- Meet every 5 years to review
and improve goals
```
```
EU 20-20-20:
-20% reduction in GHG
emissions and commitment to
20% of energy coming from
renewable sources and 20%
increase in energy efficiency
by 2020
-EU has suggested it will
increase its emissions
reduction to 30% if major GHG
producing countries also
improve their targets
```
```
Charity Campaigns and
awareness
-Spread awareness about cold
environment fragility
-Charities create campaigns and
petitions to make contact with
decision makers (e.g. the EU)
-Greenpeace is an example of a
charity spreading awareness of
cold environments’ fragility. For
example, this report assessing
the melting permafrost in Russia
```
109
In the future how are cold environments going to be managed to reduce the impact?
If climate change continues the way it is going, cold environments will most likely be affected all
over the world. Therefore, in the future there may be a demand for stricter regulations to be put in
place to protect these environments.
● Further developments into renewable energy that will lesson CO2 emissions
● Possible need to have further protection of oil exploitation as finite resources run out
● Stricter policies for reduced pollution
● Flooding mitigation if sea levels rise - if every glacier and ice sheet were to melt, sea
levels would rise by 70 metres.
110
Define environmental fragility
Environmental Fragility: The concept of an environment being vulnerable and at risk , as it lacks
the ability to be resilient and adapt to changes.
111
Why are cold environments classified as being fragile?
Cold environments are classed as environmentally fragile due to a number of reasons, causing
small changes to have large and destructive impacts.
Highly adapted ecosystem - plants and animals must be highly adapted to the extreme weather
conditions around them in order to survive. Especially in polar regions, plants and animals have
adaptations that allow them to survive in the cold temperatures . Therefore, when something in
the ecosystem changes, e.g. the temperature becomes higher, these highly adapted species find it
more difficult to cope with the changes.
Slow nutrient cycle - due to the cold temperatures and nutrient deprived environment, cold
environments’ nutrient cycles are slow. This means that things will take longer to break down,
and longer to restore if they are damaged. Plants cannot regenerate as quickly as in other
environments, which can limit their growth indefinitely. This also means that if litter or other foreign
objects are placed in the environment, they will take a long time to decompose which can affect
plant and animal behaviour.
Lack of biodiversity - due to the cold and unforgiving climate, only certain plants and animals
thrive, meaning food chains are limited and species depend on each other. If a species is
removed or damaged, this can spread throughout the entire food chain, affecting every aspect of
the ecosystem. For example, species of krill is declining in the Antarctic, which is causing penguins
to migrate to different areas, affecting seal populations.
