Unit title/key question: Glaciation
Component 1: What are glaciers?
The significance and important of ice and glaciers is not likely to
have occurred to pupils before, perhaps unless they have been
skiing.
Pupils will begin this unit by watching a documentary ‘The Power of
Ice’. This will provide them with an overview of the role of ice on
Earth and also a mental image of ice covered landscapes when they
are referred to in subsequent lessons.
Pupils should have a securing understanding of the following key
terms:
Glacier – A large mass of ice, formed from many years of snow that
has been compressed into hard ice. As well as ice, glaciers also
contain rock and sediment which acts as like sandpaper on the land
as the glacier flows across it.
Alpine glacier – A glacier that forms on a mountainside at high
altitude and moves down valleys.
Ice sheet – A mass of glacial land ice extending more than 50,000
square kilometres. The two ice sheets on Earth today cover most of
Greenland and Antarctica. Together, the Antarctic and Greenland ice
sheets contain more than 99 percent of the freshwater ice on
Earth.
Pupils will map the distribution of glaciers and identify that the
following countries have glaciers:
Iceland, Antarctica (not a country but a continent), Afghanistan,
Pakistan, China, India, Nepal, Bhutan, Myanmar, Chile, Peru,
Ecuador, Iceland, Austria, Switzerland, Italy, France, Slovenia,
Germany, Canada, the USA, Russia, New Zealand, Kenya, Tanzania,
Uganda and the Democratic Republic of Congo
Pupils should be aware of the glacier as a system:
Pupils should be able to articulate the formation process:
· Snow falls on mountains
· It is so cold, it doesn’t melt over the summer months
· Each year another layer of snow falls, compressing the old
layers. This is called ‘accumulation’.
· The air is forced out of the snow, turning it first to firn and
then glacial ice
· The glacier moves downhill
· Ice is lost from the lower section of the glacier in the zone of
ablation
· The very end of the glacier is called the snout
Pupils should understand the basics of how glaciers move:
Glaciers always flow downslope.
There are two processes:
· Internal Deformation – the intense pressure at the base of the
glacier causes solid ice to move in a plastic-like manner.
· Basal Slip – liquid water at the base can act as a lubricant and
allow the glacier to slide along. The water can either come from
melt water entering through crevasses or ice melting under pressure
at the base.
Climate governs the movement of glaciers:
· Ice sheets form in environments that are cold all year round,
limiting the availability of water. They move slowly under internal
deformation.
· Alpine glaciers are found at lower latitudes so have grater
temperature variation throughout the year leading to greater
availability of water. These glaciers move by basal sliding,
tending to move more quickly and carry out more erosion.
Component Assessment – Short quiz at the proposed end of the
unit
Component 2: Shaping the landscape – erosion, transport and
deposition
There are three weathering process:
· Biological
· Chemical
· Freeze-thaw (mechanical/physical)
Freeze-thaw is the weathering process that takes places in glacial
environments.
Glaciers carry out two forms of erosion:
1. Abrasion – pupils have already learnt about this is riparian and
coastal context in the previous two units
· Abrasion is the sandpapering effect of the ice containing
fragment of rock travelling over the Earth. Abrasion leaves behind
smooth, polished rock surfaces that may have scratches called
striations in them
2. Plucking – Meltwater beneath the glacier bonds the base to the
rock underneath. As the glacier moves, chunks of rock loosened by
freeze-thaw action are plucked away. These pieces of rock becomes
embedded in the glacier and carry out the abrasion.
Sediment is carried on top of the glacier, inside it and dragged
along the base. As the glacier moves forward, also pushes loose
material in front of it, a process called ‘bulldozing’. The
material is deposited when the ice melts. Most melting occurs as
the snout so this is where most deposition takes place. The
material the glacier dumps is called glacial till. It’s a jumble of
rock, sand and clay.
Moraines are important features for understanding past
environments. Terminal moraines, for example, mark the maximum
extent of a glacier advance (see diagram below) and are used by
glaciologists to reconstruct the former size of glaciers and ice
sheets that have now shrunk or disappeared entirely
A terminal moraine is a moraine ridge that marks the
maximum limit of a glacier advance. They form at the glacier
terminus and mirror the shape of the ice margin at the time of
deposition. The largest terminal moraines are formed by major
continental ice sheets and can be over 100 m in height and 10s of
kilometres long
Recessional moraines are found behind a terminal moraine limit
and form during short-lived phases of glacier advance or standstill
that interrupt a general pattern of glacier retreat
Lateral moraines form along the glacier side and consist of
debris that falls or slumps from the valley wall or flows directly
from the glacier surface. Where the rate of debris supply is high,
lateral moraines can reach heights of more than 100 metres
Medial moraines form where lateral moraines meet at the confluence
of two valley glaciers
Hummocky moraines form when a large chunk of a glacier breaks off
and randomly dumps the sediment it was carrying. This leaves behind
mounds of sediment – note not included on diagram.
Component Assessment – Short quiz at the proposed end of the
unit
Component 3: Glacial landforms
Erosional Landforms:
Corries (also known as cirques or cwms) are large arm-chair shaped
depressions in the side of a mountain created by the erosion power
of a glacier.
Corrie formation:
· Snow collects in a sheltered hollow on the side of a mountain.
This is usually on North-facing slopes in the northern hemisphere.
The snow doesn't melt in the summer because it is high up,
sheltered and cold.
· Every winter, more snow collects in the hollow. This becomes
compacted and the air is squeezed out leaving ice.
· The back wall of the corrie gets steeper due to freeze-thaw
weathering and plucking.
· The base of the corrie becomes deeper due to abrasion.
· As the glacier gets heavier it moves downhill. The glacier moves
out of the hollow in a circular motion called rotational
slip.
· Due to less erosion at the front of the glacier a corrie lip is
formed.
· After the glacier has melted a lake forms in the hollow. This is
called a corrie lake or tarn.
An arête is a sharp ridge that separates two corries. See diagram
below
A pyramidal peak is formed where three or more corries
and arêtes meet. The glaciers have carved away at the top of a
mountain, creating a sharply pointed summit such as Mont Blanc, The
Matterhorn and Mount Everest.
U-shaped valleys – pupils should be remind of the v-shaped valleys
river carve in the upper course. Glaciers usually follow the path
of river valleys, widening it to create a u-shape as they move
along it.
After the ice has retreated, a river often flows in the valley
again but it much smaller than the valley so is called a misfit
river.
Pupils should be able to identify these landforms on an OS
Map
A hanging valley is a tributary valley that meet the main valley
high above it, often creating s waterfall.
Truncated spurs are also formed from interlocking spurs (see
previous rivers unit). This happens when the glacier erodes the
protruding hard rock of the interlocking spur, clearing and
straightening the valley.
Fjords are flooded u-shaped valleys. They are found in places where
current or past glaciation occurred below sea level. Fjords are
formed when a glacier retreats, after creating a u-shaped valley
and the sea fills in the resulting valley floor as sea level rises.
‘Fjord’ is a Norwegian word. Norway has one of the best examples of
a fjord coastline.
Depositional Landforms:
Erratics are large boulders that have been carried and deposited by
a glacier. They are different to the underlying rock type. When the
ice retreats, these boulders are striking reminders that the
landscape was once glaciated.
Drumlins are smooth egg-shaped hills that are 100-800m long and
25-100m high. The exact mechanism of drumlin formation is not
clearly understood (excellent example of how glaciology is still
developing). It is thought that the glacier moves over previously
deposited till, smoothing and shaping it. Drumlins often appear in
groups called drumlin fields.
Component Assessment – Short quiz at the proposed end of the
unit
Component 4: People and glaciers
Pupils will explore the legacy of the UK’s glaciated environments.
They will gain an overview of land use in these landscapes:
· Farming – as glaciers scour the landscape they remove soil, once
melted they leave behind thin, acidic soil which is poor for arable
farming so is used mainly for sheep. Sheep can tolerate the cold,
wet, windy conditions and poor vegetation. Soils in valleys tend to
be thicker and richer due to deposition. The flat-bottoms of the
valleys make them suitable for machinery so farming can be more
productive. Crops include cereals, potatoes and winter feed for
livestock (hay and silage). Lowland glaciated areas are sometimes
covered by a layer of till which is very fertile e.g. East Anglia
resulting in productive farmland that is used for intensive arable
farming.
· Forestry – many upland glaciated areas of the UK are suited to
forestry. Large plantation of coniferous trees have been planted
throughout Scotland and northern England. Conifer trees are well
adapted to cope with the poor soil and steep slopes. The trees are
grown for 20-30 years then cut down for the construction industry
or making paper.
· Quarrying – Upland glaciated areas are made of hard, resistant
rock. This is quarried for a range of purposes such as construction
and road building.
· Tourism – People like to visit upland glaciated environments to
see the spectacular scenery and enjoy outdoor activities such as
mountain biking, skiing and climbing.
This opportunities all provide employment in areas with few other
opportunities.
Pupils will look at tourism in the Lake District in more detail as
an example of economic opportunities in glaciated
environments.
Key facts about the Lake District:
· Made a national park in 1951
· Has physical attractions such as lakes, mountains and outdoor
activities such as walking, mountain biking, abseiling and rock
climbing
· Has cultural attractions such as the landscapes that inspired
Wordsworth and the home of Beatrix Potter
There are social, economic and environmental impacts of tourism in
the Lake District.
Social:
· 40 million day-tripper and 6.6 million overnight guests visited
in 2018, the area only has 40,000 residents
· Over 89% of visitors travel by car causing congestion on the
narrow, winding roads
· House prices are high – 20% of properties are second homes or
holidays rentals
· Jobs is tourism as seasonal, poorly paid and unreliable
Economic:
· Tourists generated £3 billion for the Lake District in 2019
· Tourism creates jobs for local people
· Traffic congestion slows down businesses
Environmental:
· Main tourist sites are overcrowded, problems with litter, damage
to grass verges by cars and footpath are eroded
· Pollution from cars and boats on the lakes can damage
ecosystems
· Walkers can damage farmland by trampling farmland or leaving
litter and dogs can disturb sheep.
Approaches to managing tourism in the Lake District:
· Integrated transport planning offering tourists alternatives such
as travelling to the area by train and travelling around by
bus
· Traffic calming measures (speed bumps) have been installed in
villages
· The Fix the Fells project is a partnership of six
organisations lead by the National Trust. It maintains and repairs
the upland paths preventing further erosion. This is vital work
without which access to the fells would be limited with severe
impacts on the tourism industry
· The Lake District Foundation Low Carbon Cottages - This scheme
aims to reduce carbon emissions and running costs of
traditionally built holiday cottages without damaging any of their
essential character. Working with holiday cottage owners and
letting companies, they want to prove that cottages can meet the
highest of environmental standards without it costing the earth,
either to the owners or to the holidaymakers.
Some of the economic activities can come into direct conflict with
each other. Pupils will look at two examples, the construction of
wind turbines and plans for a zip wire in the Lake District.
The wind turbines were constructed in 2012 to generate electricity
for the Kirkstone Pass Inn which had previously relied on diesel
generators. Some people feel that the turbines detract for the
natural landscape whilst others argue that they are good for the
environment and have secured the future of the pub thereby
maintaining local jobs.
In 2014 a proposal was put forward to build four parallel mile long
zip wires above Glenridding in the Lake District. Plans were
eventually dropped. Pupils should consider whether the zip wires
should have been built considering the economic benefit of job
creation versus maintaining the vista.
Component Assessment – Short quiz at the proposed end of the
unit
Knowledge & vocabulary
Substantive Knowledge
Glacier – A large mass of ice, formed from many years of snow that
has been compressed into hard ice. As well as ice, glaciers also
contain rock and sediment which acts as like sandpaper on the land
as the glacier flows across it.
Alpine glacier – A glacier that forms on a mountainside at high
altitude and moves down valleys.
Ice sheet – A mass of glacial land ice extending more than 50,000
square kilometres. The two ice sheets on Earth today cover most of
Greenland and Antarctica. Together, the Antarctic and Greenland ice
sheets contain more than 99 percent of the freshwater ice on
Earth.
The following countries have glaciers: Afghanistan, Pakistan,
China, India, Nepal, Bhutan, Myanmar, Chile, Peru, Ecuador,
Iceland, Austria, Switzerland, Italy, France, Slovenia, Germany,
Canada, the USA, Russia, New Zealand, Kenya, Tanzania, Uganda and
the Democratic Republic of Congo
Antarctica and Iceland have ice sheets.
Glacier formation process:
· Snow falls on mountains
· It is so cold, it doesn’t melt over the summer months
· Each year another layer of snow falls, compressing the old
layers. This is called ‘accumulation’.
· The air is forced out of the snow, turning it first to firn and
then glacial ice
· The glacier moves downhill
· Ice is lost from the lower section of the glacier in the zone of
ablation
· The very end of the glacier is called the snout
Glaciers always flow downslope.
There are two processes:
· Internal Deformation – the intense pressure at the base of the
glacier causes solid ice to move in a plastic-like manner.
· Basal Slip – liquid water at the base can act as a lubricant and
allow the glacier to slide along. The water can either come from
melt water entering through crevasses or ice melting under pressure
at the base.
Climate governs the movement of glaciers:
· Ice sheets form in environments that are cold all year round,
limiting the availability of water. They move slowly under internal
deformation.
· Alpine glaciers are found at lower latitudes so have grater
temperature variation throughout the year leading to greater
availability of water. These glaciers move by basal sliding,
tending to move more quickly and carry out more erosion.
There are three weathering process:
· Biological
· Chemical
· Freeze-thaw (mechanical/physical)
Freeze-thaw is the weathering process that takes places in glacial
environments.
Glaciers carry out two forms of erosion:
1. Abrasion – pupils have already learnt about this is riparian and
coastal context in the previous two units
· Abrasion is the sandpapering effect of the ice containing
fragment of rock travelling over the Earth. Abrasion leaves behind
smooth, polished rock surfaces that may have scratches called
striations in them
2. Plucking – Meltwater beneath the glacier bonds the base to the
rock underneath. As the glacier moves, chunks of rock loosened by
freeze-thaw action are plucked away. These pieces of rock becomes
embedded in the glacier and carry out the abrasion.
Sediment is carried on top of the glacier, inside it and dragged
along the base. As the glacier moves forward, also pushes loose
material in front of it, a process called ‘bulldozing’. The
material is deposited when the ice melts. Most melting occurs as
the snout so this is where most deposition takes place. The
material the glacier dumps is called glacial till. It’s a jumble of
rock, sand and clay.
Moraines are important features for understanding past
environments. Terminal moraines, for example, mark the maximum
extent of a glacier advance (see diagram below) and are used by
glaciologists to reconstruct the former size of glaciers and ice
sheets that have now shrunk or disappeared entirely
A terminal moraine is a moraine ridge that marks the
maximum limit of a glacier advance. They form at the glacier
terminus and mirror the shape of the ice margin at the time of
deposition. The largest terminal moraines are formed by major
continental ice sheets and can be over 100 m in height and 10s of
kilometres long
Recessional moraines are found behind a terminal moraine limit
and form during short-lived phases of glacier advance or standstill
that interrupt a general pattern of glacier retreat
Lateral moraines form along the glacier side and consist of
debris that falls or slumps from the valley wall or flows directly
from the glacier surface. Where the rate of debris supply is high,
lateral moraines can reach heights of more than 100 metres
Medial moraines form where lateral moraines meet at the confluence
of two valley glaciers
Hummocky moraines form when a large chunk of a glacier breaks off
and randomly dumps the sediment it was carrying. This leaves behind
mounds of sediment
Erosional Landforms:
Corries (also known as cirques or cwms) are large arm-chair shaped
depressions in the side of a mountain created by the erosion power
of a glacier.
Corrie formation:
· Snow collects in a sheltered hollow on the side of a mountain.
This is usually on North-facing slopes in the northern hemisphere.
The snow doesn't melt in the summer because it is high up,
sheltered and cold.
· Every winter, more snow collects in the hollow. This becomes
compacted and the air is squeezed out leaving ice.
· The back wall of the corrie gets steeper due to freeze-thaw
weathering and plucking.
· The base of the corrie becomes deeper due to abrasion.
· As the glacier gets heavier it moves downhill. The glacier moves
out of the hollow in a circular motion called rotational
slip.
· Due to less erosion at the front of the glacier a corrie lip is
formed.
· After the glacier has melted a lake forms in the hollow. This is
called a corrie lake or tarn.
An arête is a sharp ridge that separates two corries. See diagram
below
A pyramidal peak is formed where three or more corries
and arêtes meet. The glaciers have carved away at the top of a
mountain, creating a sharply pointed summit such as Mont Blanc, The
Matterhorn and Mount Everest.
U-shaped valleys – pupils should be remind of the v-shaped valleys
river carve in the upper course. Glaciers usually follow the path
of river valleys, widening it to create a u-shape as they move
along it.
After the ice has retreated, a river often flows in the valley
again but it much smaller than the valley so is called a misfit
river.
A hanging valley is a tributary valley that meet the main valley
high above it, often creating s waterfall.
Truncated spurs are also formed from interlocking spurs (see
previous rivers unit). This happens when the glacier erodes the
protruding hard rock of the interlocking spur, clearing and
straightening the valley.
Fjords are flooded u-shaped valleys. They are found in places where
current or past glaciation occurred below sea level. Fjords are
formed when a glacier retreats, after creating a u-shaped valley
and the sea fills in the resulting valley floor as sea level
rises.
Depositional Landforms:
Erratics are large boulders that have been carried and deposited by
a glacier. They are different to the underlying rock type. When the
ice retreats, these boulders are striking reminders that the
landscape was once glaciated.
Drumlins are smooth egg-shaped hills that are 100-800m long and
25-100m high. It is thought that the glacier moves over previously
deposited till, smoothing and shaping it. Drumlins often appear in
groups called drumlin fields.
Economic opportunities in glaciated landscapes:
· Farming – as glaciers scour the landscape they remove soil, once
melted they leave behind thin, acidic soil which is poor for arable
farming so is used mainly for sheep. Sheep can tolerate the cold,
wet, windy conditions and poor vegetation. Soils in valleys tend to
be thicker and richer due to deposition. The flat-bottoms of the
valleys make them suitable for machinery so farming can be more
productive. Crops include cereals, potatoes and winter feed for
livestock (hay and silage). Lowland glaciated areas are sometimes
covered by a layer of till which is very fertile e.g. East Anglia
resulting in productive farmland that is used for intensive arable
farming.
· Forestry – many upland glaciated areas of the UK are suited to
forestry. Large plantation of coniferous trees have been planted
throughout Scotland and northern England. Conifer trees are well
adapted to cope with the poor soil and steep slopes. The trees are
grown for 20-30 years then cut down for the construction industry
or making paper.
· Quarrying – Upland glaciated areas are made of hard, resistant
rock. This is quarried for a range of purposes such as construction
and road building.
· Tourism – People like to visit upland glaciated environments to
see the spectacular scenery and enjoy outdoor activities such as
mountain biking, skiing and climbing.
Key facts about the Lake District:
· Made a national park in 1951
· Has physical attractions such as lakes, mountains and outdoor
activities such as walking, mountain biking, abseiling and rock
climbing
· Has cultural attractions such as the landscapes that inspired
Wordsworth and the home of Beatrix Potter
There are social, economic and environmental impacts of tourism in
the Lake District.
Social:
· 40 million day-tripper and 6.6 million overnight guests visited
in 2018, the area only has 40,000 residents
· Over 89% of visitors travel by car causing congestion on the
narrow, winding roads
· House prices are high – 20% of properties are second homes or
holidays rentals
· Jobs is tourism as seasonal, poorly paid and unreliable
Economic:
· Tourists generated £3 billion for the Lake District in 2019
· Tourism creates jobs for local people
· Traffic congestion slows down businesses
Environmental:
· Main tourist sites are overcrowded, problems with litter, damage
to grass verges by cars and footpath are eroded
· Pollution from cars and boats on the lakes can damage
ecosystems
· Walkers can damage farmland by trampling farmland or leaving
litter and dogs can disturb sheep.
Approaches to managing tourism in the Lake District:
· Integrated transport planning offering tourists alternatives such
as travelling to the area by train and travelling around by
bus
· Traffic calming measures (speed bumps) have been installed in
villages
· The Fix the Fells project is a partnership of six
organisations lead by the National Trust. It maintains and repairs
the upland paths preventing further erosion. This is vital work
without which access to the fells would be limited with severe
impacts on the tourism industry
· The Lake District Foundation Low Carbon Cottages - This scheme
aims to reduce carbon emissions and running costs of
traditionally built holiday cottages without damaging any of their
essential character. Working with holiday cottage owners and
letting companies, they want to prove that cottages can meet the
highest of environmental standards without it costing the earth,
either to the owners or to the holidaymakers.
The wind turbines were constructed in 2012 to generate electricity
for the Kirkstone Pass Inn which had previously relied on diesel
generators. Some people feel that the turbines detract for the
natural landscape whilst others argue that they are good for the
environment and have secured the future of the pub thereby
maintaining local jobs.
In 2014 a proposal was put forward to build four parallel mile long
zip wires above Glenridding in the Lake District. Plans were
eventually dropped. Pupils should consider whether the zip wires
should have been built considering the economic benefit of job
creation versus maintaining the vista.
Disciplinary Knowledge
Glaciologists study glaciers. They use repeat photograph to examine
whether a glacier is in retreat or advance. Glaciologists use hot
water to carve caves underneath glaciers to study the processes
taking place.
Glaciers are considered as systems with inputs, outputs and
processes.
‘Fjord’ is a Norwegian word. Norway has one of the best examples of
a fjord coastline.
The exact mechanism of drumlin formation is not clearly understood
(excellent example of how glaciology is still developing).
The impacts of change are considered from different perspectives in
geography. At KS3 and 4 level these perspectives are social,
economic and environmental.
Subject methods and resources
· PPT to display LO, key terms, cloze statements, data, video clips
and images
Prior Knowledge
Rivers and Coasts units – erosion and weathering principles
Assessment of components and summative assessment of the unit
(composite).
Component 1
Component Assessment – Short quiz at the proposed end of the
unit
Component 2
Component Assessment – Short quiz at the proposed end of the
unit
Component 3
Component Assessment – Short quiz at the proposed end of the
unit
Component 4
Component Assessment – Short quiz at the proposed end of the
unit
Composite:
Low Stakes:
Cold-Calling with robust creation of a collaborative, supportive
learning atmosphere i.e. no silly answers or questions, just
opportunities to learn. Pupils to be offered opportunity to select
a peer if they are unsure of the answer themselves after thinking
time.
Mini whiteboards for answers to Do Now starters, low stakes for
pupils but also handy for teacher to gain snapshot of class when
held up
Think, pair, share giving pupils chance to think through their
answers to more challenging questions
Likely misconceptions and suggested strategies to tackling
them