Combined: all glaciation cards for Y12 exams

What type of systems are glaciated landscapes

Open systems

How is energy and matter shared in a glacier

By inputs and outputs

Where do inputs to glacial systems go

Accumulation zone

Where do outputs into glacial systems go

Ablation zone

Name 4 inputs of glacial systems

• Kinetic energy from wind and moving glaciers

• Thermal energy from sun

• Potential energy from position of material on slopes

• Material/debris/load from deposition, weathering, mass movement, precipitation

Name 3 outputs of glaciated systems

meltwater, debris, icebergs

What happens when inputs = outputs

State of equilibrium exists

What happens when state of equilibrium exists

Glacial mass remains constant

What feedback loop exists in glaciers

Negative feedback loop. System undergoes self-regulation and changes its form until equilibrium is restored

What is glacial mass balance

Difference between the amount of snow and ice accumulation and the amount of ablation occurring in a glacier over a 1 year period

What is glacial budget

Accumulation - ablation

How does glacial budget vary

It varies by season

Summer - ablation exceeds accumulation

Winter - accumulation exceeds ablation

What is the accumulation zone

When accumulation exceeds ablation (higher levels)

What is the ablation zone

When ablation exceeds accumulation (lower levels

How do glacial landforms develop

Due to a variety of interconnected climactic and geomorphic processes
Driven by flows of energy and materials within the glacial system

What are the energy types that impact geomorphic landforms

Solar, kinetic, potential / GPE

What are the materials that impact geomorphic landforms

Precipitation, ice, rock debris/sediment, meltwater

How does gravity impact glaciers

Causes glaciers to flow downslope from accumulation zones to lower elevations
Also transfers ice and sediment through the glacial system

How does radiation impact glaciers

• Solar radiation contributes to surface melting

• This produces meltwater, which can enhance erosion and deposition

• Radiation increases energy input into the system, increasing ablation

How do temperature variations influence glaciers

They influence melting rates, freeze-thaw weathering, and ice movement

How does precipitation impact glaciers

Adds to the glacial mass balance
Increases pressure and flow
The main input

Describe the different flows of material (4)

Rock debris - produced by weathering and mass movement
Till - eroded from valley floors and sides
Meltwater - carries fine sediments
Ice

Different parts of glaciers

Supra glacial = on the glacial surface
Englacial = within the glacier
Subglacial = beneath the glacier

What are the three types of weathering

Freeze thaw
Nivation
Chemical weathering (has sub-types)

Describe freeze thaw weathering process

water enters crack in rock
temperatures= >0 degrees--> water freezes and expands by about 9%
repeated cycles widen cracks and break rock into angular fragments
Produces angular debris that contributes to glacial sediment supply

what is nivation and how does the process work

Nivation is the combination of freeze-thaw weathering, erosion and mass movement beneath a snow patch, which gradually enlarges a hollow on a mountain slope.

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• Snow patches insulate the ground, encouraging freeze-thaw weathering.

• Meltwater moves through the snow and transports weathered material

• saturated soil moves downslope via solifluction.

• Over time this deepens and widens the hollow, making it more likely to trap snow (positive feedback).

Where does chemical weathering occur

Around glacial meltwater streams
On exposed rock surfaces during summer melt
Limited in cold conditions but increases during interglacial periods

When does chemical weathering occur

In warmer periods between glaciations

What is the purpose of chemical weathering

To produce sediment supply, enabling geomorphic processes to occur

What are the three sub-types of chemical weathering

Carbonation
Hydrolysis
Oxidation

Explain carbonation

Rainwater absorbs CO2 from atmosphere, forming weak carbonic acid
Acid reacts with carbonate rocks
Rocks dissolve in solution

Explain hydrolysis

• Water reacts with silicate materials in rocks e.g. granite

• causes rocks to break down and form new minerals e.g. clay

• happens because rainwater is acidic

• removes co2 from the atmosphere

describe the process of oxidation

oxygen reacts with iron containing minerals
forming iron oxide (rust) weakening the rock

What are the two types of glacial erosion

Plucking + abrasion

Explain plucking

• Large blocks of bedrock are lifted and removed by a glacier

• Meltwater enters cracks and joints in the bedrock beneath the glacier

• Water refreezes, bonding the rock to the ice

• As the glacier moves, it pulls away and removes blocks of rock

• The loosened rock becomes embedded in the glacier

• Most effective in warm-based glaciers where meltwater is present

Explain abrasion

occurs when rock fragments embedded in the base of a glacier scrape and grind the bedrock beneath
debris within glacier acts like sandpaper
fragments grind against the valley floor and sides as the glacier moves
wearing down the rock surface
faster the movement--> stronger the erosional power
most effective when basal sliding occurs due to meltwater lubricating the glacier bed
Produces rock flour, contributing to fine sediment load

What are the 3 types of mass movement/transportation

Rock falls, slumping + sliding

Describe sliding

1. Friction, pressure and heat from ice moving over bedrock leads to melting.

2. Meltwater then acts as a lubricant, assisting further glacial flow

(Also known as basal sliding)

What are the impacts of sliding

Enhances glacier velocity
Increases erosional power

Describe rock falls

Fragments of rock detach from cliff face and move rapidly downslope due to gravity

often triggered by processes that have made the rocks weaker e.g. freeze thaw weathering

What causes rock falls

Weathered debris falls under gravity from the exposed rock above the ice down onto the edge of the glacier

Describe slumping

• A type of mass movement where saturated soil or soft rock moves downslope along a curved slip plane in a rotational movement

• Occurs when water reduces cohesion and increases weight, often after slope undercutting or steepening

• Leaves a stepped or terraced slope profile

What are the 2 types of glacial erosion

Plucking and abrasion

Describe how abrasion works and when it occurs

Debris within glacier acts like sandpaper, with fragments grinding against the valley floor and sides as the glacier moves.

This wears the rock surface down.

It is most effective when basal sliding occurs due to meltwater lubricating the glacier bed

What are the types of sediment transported (4)

Rock flour
Sand and gravel
Pebbles
Large boulders

What is till

Glacial sediment that is unsorted and unstratified
Deposited by ice, not meltwater

What are the six types of erosional landforms

Corries, aretes, pyramidal peaks, troughs, roche moutonées, striations

How do corries form

• Starts with nivation of a small hollow on a hillside

• Snow accumulates year on year

• Hollow enlarges

• Snow compacts and compresses into glacial ice

• Ice moves by rotational slip under its own weight

• This rotational movement causes plucking of the back wall, making it steeper

• Debris within the ice causes abrasion, deepening and smoothing the hollow

• As erosion continues, the hollow becomes overdeepened

• The thinner ice at the front erodes less effectively, leaving a rock lip

• A rock lip forms at the front, sometimes with deposited moraine

How do aretes form

When two or more corries are formed, there is a narrow ridge between them
The two glaciers erode downwards and pluck from the rock

How do pyramidal peaks form

1. Three or more corries form, leaving a peak

2. Corries erode backwards, meaning the ridge between them becomes more narrow

3. The remaining central point becomes a sharp isolated peak

4. Freeze-thaw weathering further sharpens the summit

How do glacial troughs form

• Formed when a glacier occupies a pre-existing river valley

• the glacier moves downslope under gravity, eroding valley through plucking and abrasion.

• This widens the valley sides and deepens the floor,

• the original V-shape is transformed into a U-shaped valley.

How do hanging valleys form

• Where a tributary glacier joins a larger main glacier

• The main glacier is thicker, so has greater erosive power and erodes more deeply (e.g. abrasion and plucking)

• The tributary glacier erodes less deeply, leaving its valley hanging above the main valley after glaciation

• Often marked by a waterfall

How do truncated spurs form

• Before glaciation, river valleys have interlocking spurs formed by fluvial erosion

• As a glacier moves through the valley, it is powerful and rigid, so it overrides and cuts through the spurs rather than winding around them

• Abrasion and plucking erode the ends of the spurs, truncating them and creating steep, straight valley sides

• After glacial retreat, these truncated spurs remain as steep ridges along the sides of a U-shaped valley

How do ellipsoidal basins form

• in areas where ice accumulates, rotational slip occurs, concentrating erosion in one area

• rocks embedded in the glacier scrape against the bedrock, grinding down the surface (← abrasion)

• plucking then occurs, pulling chunks of rock away from the bedrock, making the basin deeper and rougher

• erosion makes a deep, rounded hollow at the centre of the ice movement which becomes ellipsoidal due to ice flow patterns

How do roche moutonnées form

• A glacier moves over a resistant rock.

• The upstream side is smoothed by abrasion as ice and debris scrape over it, sometimes leaving striations.

• As ice flows over the top, pressure causes plucking on the downstream side

• This creates a steep, jagged slope.

• This shows the direction of ice movement.

How do striations form

• As glaciers move, they collect debris which becomes embedded in the ice

• These embedded fragments are dragged across the bedrock surface, creating scratches and grooves (striations)

• This is the result of abrasion, as sediment frozen into the base of the glacier scours the bedrock

• They run parallel to the direction of ice movement and can be used to determine the direction of past glacier flow

Name the 4 types of depositional landforms

moraine
erratics
drumlins
till sheets

What are the five types of moraine

Terminal, lateral, medial, recessional, ground

Describe ground moraine

• unsorted till deposited beneath the glacier (subglacial)

• Formed by lodgement (material pressed into the bed) and melt-out

• Creates a widespread, thin, irregular covering across the valley floor

• Produces a gently rolling landscape

Describe terminal moraine

• debris and till deposited in a ridge at the maximum advance of the ice

• marks the furthest advance of a glacier

• formed from material pushed and dumped at the glacier snout during maximum advance

• appears as a ridge of unsorted till across the valley floor, sometimes damming meltwater to form lakes

• transverse (runs across the valley)

Describe lateral moraine

A ridge of rocks and debris left along the sides of a glacier.

How it forms:

• Rocks fall from valley sides (often by Freeze–thaw weathering)

• Glacier carries them along the edges

• When ice melts they’re dropped as ridges on the sides

Describe medial moraine

• what it is: A ridge of till running along the centre of a glacial valley.

• how it is formed: It forms when two glaciers merge, combining their lateral moraines.The debris is transported supraglacially along the middle of the glacier and deposited after melting.

Describe recessional moraine

• Transverse to the valley

• Ridges of unsorted till deposited during temporary pauses in glacial retreat

• Form where the glacier remains stationary long enough for material to accumulate at the snout

• Mark stages of retreat after the glacial maximum

Describe erratics

large rocks/ boulders that have been picked up by a glacier/ ice sheet
carried along and dropped in an area of completely different geology

Describe drumlins

Half-egg shaped hills of till
Up to 1500m long and 100m high
Upstream end is wide and tall and the downstream end is narrow and long
Often form in groups
Formed beneath a glacier or ice sheet
Shaped by subglacial deposition

How do drumlins form

Till got stuck around a rock or hill sticking out into the glacier
Original mound of till gets streamlined when the ice readvances over it

Describe till sheets - how they are formed, where they are formed, what landscapes they create

• Formed from extensive deposition of unsorted glacial till as ice retreats.

• Created where the glacier stagnates, depositing a thick, widespread layer of till.

• Landscape is usually flat or gently undulating, often covering broad lowland areas.

• More common in regions previously covered by ice sheets rather than valley glaciers.

What is the case study for a glaciated landscape being used by humans

The Grande Dixence dam in Val des Dix, Switzerland

Describe the Grande Dixence dam, when it was built, how much it cost, and how many glaciers it’s fed by

Highest gravity dam in the world
Constructed from 1950 onwards
Cost 1.6 billion Swiss Francs
Fed by 35 glaciers

Explain the concept of a gravity dam

Gravity holds dam into the ground, stopping the weight from the water pushing the dam down

What does the Grande Dixence dam provide Switzerland with?

it provides Switzerland with HEP, hence why they wanted to spend so much money building it. By creating energy within the country this means Switzerland doesn't have to rely on external energy imports as much

How much water does the Grande Dixence dam store

Over 400 million m3 of water a year

Is the dam used all year round

It stores meltwater in the summer so that it can be used in the winter to generate more energy. More energy is needed in winter as people need more heating etc

How many homes does the dam fuel

400,000 Swiss homes per year

How is water transported to the Grande Dixence dam?

Through 100km of tunnels and 4 pumping stations

How many power stations are in the grande Dixence dam?

Four

What percentage of stored water is used for electricity generation?

85%

Why is a glaciated landscape suitable for the Grande Dixence dam?

Steep sided valleys, formed by glaciated, allow for the dam to store a large volume of water.

How does the dam impact the environment -> tourists

It is a big tourist spot so its aesthetics need to be maintained
This means pumping stations are built underground or well-concealed so that the environment remains attractive for walkers, cyclists and hikers

Is there any pollution because of the dam

Holding water back results in lots of pollution
We see this in the Borgne River below the dam, where there is reduced flow
In the Borgne there are high concentrations of pollutants

What is the water in the dam used for (percentages)

85% is used for electricity generation
15% is used to deal with the problems of sedimentation

What is sedimentation

When we hold water back, this means the lake above is stagnant until we let it flow
Therefore a lot of sediment is held back and there isn't enough energy to push it through
Hence, 15% of the dam's water is used to flush the sediment through

Effects of trapping sediment -> clear water

• The trapping of sediment behind the dam leads to very clear water being returned into the natural river channels below the power stations

• This has excess energy as none is being used to transport sediment, resulting in increased channel erosion due to more kinetic energy

grande dixence dam

Effects of trapping sediment -> lack of discharge etc

• The below-dam rivers lack discharge meaning they can dry up in the summer

• The size of the channels have decreased as you go further downstream

• The amount of sediment flowing into Lake Geneva has halved since the dam's construction

How will the dam's impacts on the glacial system change in the future

Because of climate change there will be higher rates of glacial meltwater
This means there is more meltwater available, creating more HEP
But the glacier will shrink because of climate change, overall meaning the meltwater supply will diminish
This will alter sediment supply even further

What is the case study for a periglacial landscape being used by people

Alaska

Describe Prudhoe Bay

It used to be a small inuit settlement but is now a town with an economy based on oil extraction

Describe the Trans-Alaskan pipeline

It is 1300km long, running from Prudhoe Bay to Valdez
Transports up to 1.4 million barrels of oil each day
Over 600km is built on stilts to prevent permafrost from melting
Finished in 1977

Name the human activity that is taking place in Alaska (3)

Gravel extraction, oil extraction, and mining

What are the reasons behind the resource extraction in Alaska

In 1968, vast deposits of oil were found in Prudhoe Bay, leading to the Trans-Alaskan pipeline being built
Additionally, the USA wants to become self-sufficient and not rely on importing from other countries, hence why there is pressure to drill in Alaska
Due to conflict in Russia and the middle east, the US prefers to harness their own oil and sell it rather than importing it

How much gas is in Alaska/Arctic circle

The USGS estimated 30% of the world's undiscovered gas is waiting to be found in the Arctic circle
It is believed that Area 1002 in Alaska could contain over 16 billion barrels of oil

Name three landscape impacts of the Trans-Alaskan pipeline

• Solifluction

• organic matter being released when permafrost thaws

• plant growth rates being altered

Explain the impacts of the Trans-Alaskan pipeline (solifluction)

• Buildings and infrastructure release heat, leading to thawing of permafrost and a longer period of melting for the active layer

• heat and the melting of the active layer causes subsidence

• This means there is an increase in the mobility of the active layer, causing solifluction

• Solifluction lobes may then form

🌰 Trans-alaskan pipeline RELEASES HEAT —> THAWS PERMAFROST —> MELTS ACTIVE LAYER —> CAUSES SUBSIDENCE —> CAUSES SOLIFLUCTION

Explain the impacts of the Trans-Alaskan pipeline (organic matter)

Organic matter frozen in the permafrost is a major source of methane in the Arctic
It consists of dead plants and animals frozen deep within the permafrost, containing large amounts of carbon
As permafrost thaws, the organic matter decays, releasing CO2 and methane into the atmosphere

Explain the impacts of the Trans-Alaskan pipeline (plant growth)

• When permafrost melts, there is more water available so plants grow rapidly.

• However, thawing removes the impermeable barrier provided by frozen ground.

  • This increases drainage.

• This leads to drier soils over time, reducing vegetation growth

• This impacts animal habitats and food supply, disrupting local ecosystems.

What is area 1002

An area of 6070 km2 in the northwest part of the Arctic
It is not protected by wilderness designation
Could hold large petroleum deposits
It is the core calving ground for the Porcupine caribou
It is inside the ANWR

US government plans with area 1002

In Jan 2021, Trump approved plans for oil and gas extraction in the ANWR
In June 20221, Biden halted this extraction

How were problems associated with building the Trans-Alaskan pipeline solved?

• Pipeline was raised above the ground and supported by refrigerants to ensure heat is not conducted into the ground, also allowing animals to move below it (prevents migration routes from being blocked)

• Pipeline takes a zigzag route across the surface to be able to adjust to ground movements

What are the effects of permafrost thawing on landforms

• Large scale thawing of permafrost leads to waterlogged soil (thermokarst), which forms alases

• Pingos collapse and become ognips

• There will be more solifluction and more solifluction lobes will form

How has construction reduced the risk of permafrost melting

Careful engineering has been done to avoid altering the thermal balance of the ground, which would result in thawing of permafrost and ground subsidence
Homes and buildings are built above the surface to allow air to circulate and to remove heat
Large structures and roads are built on gravel bads