Glaciers Flashcards

Ice age meaning

An ice age is a long period of time when global temperatures fall and ice extends across the planet.

Glacier / interglacial periods

A glacial period is when the Earth is colder and lasts for 100, 000 years.

An interglacial is a warmer period of time that usually lasts for 10, 000 years.

Changes in the Earth’s orbit is the only thing powerful enough to cause this shift.

glacier, alpine glacier and ice sheet meaning, & how they form

and what is firn?

A glacier is a mass of snow and ice. Alpine glaciers are those that form in the mountains and ice sheets cover huge areas of land.

They form when snow falls and does not melt. Snow that has not melted for at least a year is called firn. As the snow builds up in layers, the weight compresses it into ice. 

firn meaning

Snow that has not melted for at least a year

Glacial Regions Today

There are a number of glaciated regions left in the UK. Most of them are alpine glaciers but there are a couple of ice sheets.

1. Greenland Ice Sheet

2. Antarctic Ice Sheet

3. Himalayan Glaciers

4. Patagonian Ice Sheet

main features of a glacier

• The Zone of Accumulation

• The Zone of Ablation

• crevasses

• snout

• The Zone of Accumulation

where more snow falls then melts so the snow accumulates and builds up. This is usually higher up in the mountains where it is colder.

The Zone of Ablation

where more snow melts than falls so the glacier begins to retreat. This is usually further down the mountain where it is warmer or during summer months.

crevasses

Large cracks in the glaciers

snout meaning

The end of the glacier

Weathering meaning

the process of breaking down land in place

Freeze thaw weathering

when water seeps into cracks or joints in the rock and freezes. When water freezes, it expands and puts pressure on the rock. Repeated cycles of freezing and thawing gradually widen the cracks and weaken the rock, eventually causing fragments to break off and the rocks drop to the floor creating piles of material called scree.

How do Glaciers Erode?

• Plucking Pressure and friction under the glacier cause some ice at the base to melt. This meltwater seeps into cracks in the bedrock. . The meltwater refreezes inside cracks, expands, and forces the cracks wider. The refrozen ice bonds the glacier to the loosened rock block When the glacier moves, it takes this material with it. This is very effective in rocks that have joints or cracks that the water can seep into before freezing around the rock.

• Abrasion is also known as the ‘sandpaper’ effect. Rocks frozen into the base of the glacier scrape against the valley floor and sides and wear it away. They often leave scratches in the rock called striations.

• Basal slip meaning

• is when the glacier slides down the mountain under its own weight. There is often meltwater at the base of the glacier (due to either melting or compression melting) which helps the glacier to slide. 

• rotational slip meaning

• If the movement is more curved over dips and hollows in the mountain, it is called rotational slip

• internal deformation meaning

• If the glacier is frozen solid to the ground which is often during winter, gravity pulls the glacier downhill but instead of sliding, it behaves like a hard plastic, and the ice layers deform.

mass balance meaning

Glaciers can also retreat or advance depending on whether they are growing in size or melting. This is called mass balance. If accumulation is greater than ablation, the glacier will advance down the mountain. If ablation is greater than accumulation, the glacier will melt and retreat up the mountain

How do Glaciers Transport Material?

As the glacier moves downhill, it pushes loose rock and material in front of it in a process known as bulldozing.

What is deposition?

Deposition is when material is dropped as the ice melts.

glacial till meaning

Deposited material is called glacial till. This is often deposited as a glacier retreats. 

creation of an outwash plain

An outwash plain is a broad, flat area formed by sediments deposited by meltwater flowing from a glacier’s snout

Ahead of the glacier, meltwater will carry finer material further from the snout of the glacier creating an outwash plain. This material is sorted; the large material is deposited closer to the glacier and the finer material is transported a further distance

Moraine meaning

landforms formed by the deposition of the glacial till

Corries meaning

Corries are large hollowed out depressions (almost like an armchair) on the upper slopes of a mountain.

They have a steep back and a raised ‘lip’ at the front. A corrie may contain a lake called a tarn.

Formation of corries (Erosional)

1. Snow accumulates in the sheltered hollow on a hillside. It does not melt in the summer as it is high up the mountain and sheltered.

2. Freeze-thaw weathering and slumping enlarges the hollow and forms scree within the hollow

3. The snow turns into ice and a small corrie glacier is formed

4. The glacier moves through rotational slip and abrades the hollow making it deeper.

5. Plucking makes the back wall of the corrie steeper.

6. There is reduced erosion at the front of the corrie due to the ice being thinner and forming a raised lip.

7. Sometimes moraine can be deposited at the lip

8. A tarn is a corrie lake that may form in the bottom of a corrie

e.g. Red Tarn in the Lake District

Formation of aretes and Pyramidal Peaks (erosional)

If two corries form back to back, it creates a high, narrow ridge called an arete that separates the two corries.

If three or more corries form, there may be a single peak called a pyramidal peak.

What landforms form in glacial valleys?

• Glacial Trough

• Truncated Spurs

• Hanging Valleys

• Ribbon Lakes

Glacial Trough

When a glacier moves through a V-shaped valley, abrasion and plucking deepens and widens it. This creates a wide valley with a flat bottom and steep sides.

• Truncated Spurs

Interlocking spurs are when ridges of hard material jut out into the valley or the path of a river. Glaciers erode through these, cutting them off halfway up the valley sides. This leaves a rounded piece of land at the edge of the valley.

Hanging Valleys

Smaller tributary valleys may have had smaller glaciers forming in them. They were unable to erode down to the same level as the main glacier and are left hanging over the main glacial valley.

Today, these often have waterfalls.

Ribbon lakes

These are long, narrow lakes resulting from glacial erosion of the trough.

Softer rock on the valley floor is deepened further than harder rock.

 Water fills these deeper areas.

moraine meaning (depositional)

Any material transported by a glacier is called moraine.

This can be carried beneath the glacier, within in or on top of it.

When a glacier reduced in size, material it is carrying is deposited.

Terminal moraine

Material deposited at the end (snout) of the glacier

Lateral moraine

Material deposited along the sides of the glacier. This is usually made up of weathered material that has fallen from the sides of the valley

Medial moraine

Material deposited in the middle of a glacier. This is formed from two lateral moraines merging together where two glaciers meet

Ground moraine

This is material that is deposited across the ground as a glacier retreats

Recessional moraine

These run parallel to terminal moraines and they mark the different positions of the glacier as it retreats

A recessional moraine forms when a glacier, while generally retreating, temporarily halts its movement

glacial till meaning

Once material is deposited, it is called glacial till or boulder clay which is made from a mixture of different sized sediment. 

Drumlins (depositional)

This is an egg shaped hill formed from the deposition of moraine. 

A boulder or rock (obstacle) is in the path of the glacier. Material (that is transported beneath the glacier) known as ground moraine is deposited around this.

As the glacier moves over, the pressure shapes the material into the typical egg shaped hill of a drumlin.

The gentle sloping lee end points to the direction of ice movement.

Erratics meaning (depositional)

These are rocks that have been deposited by a glacier.

They are usually made of a rock type that is not usually found in that area.

They have been transported by the glacier from one area and deposited in another.

Meltwater & how it creates an outwash plain (depositional)

As the glacier melts, water carries finer material (glacial till) further away from the glacier where it is deposited creating an outwash plain.

Compared to moraine, this material is sorted according to size with larger material deposited closer to the glacier and finer material carried further.

Central Lake District

The Central Lake District has mountains and ridges cut by wide, steep-sided ‘U' shaped valleys often occupied by ribbon lakes such as Windemere.  

• ribbon lake: Windermere

• Langdale is a spectacular U shaped valley, with large lateral moraines running up the sides.

• There is a hanging valley at Grisedale.

Farming in glacial landscapes difficulties

Farming crops is difficult due to

• Thin, infertile soils

• Heavy relief rainfall leading to soil erosion and flooding

• Cold temperatures results in a short growing season

It is possible for animal grazing in the area. Sheep were introduced to the Scottish Highlands due to demand for wool from the textile industry. More recently there has been deer for venison and cattle for beef. In the summer they are able to graze highland areas and in the winter they are kept in farms on the valley floor.

The valley floor is sometimes more suitable for farming due to the flatter land, less extreme climate and the large glacial deposits creating more fertile soils. This can be used for growing cereal, grass for hay and potatoes. The only issue is the land here is limited compared to more open farms in other rural areas.

Forestry in glacial landscapes

• Evergreen (coniferous) forests are planted in upland areas, as they can deal with this environment

• New forests can help lessen soil erosion and counter the impact of deforestation elsewhere

• Trees are felled for timber and provide job opportunities which boost the local economy

Wood is used for timber for furniture and building construction and to make wood chips for gardens and biofuel. It is also perfect for creating paper. 

e.g. Grizedale Forest in the Lake District near Windermere

Tourism in glacial landscapes

• The dramatic landscapes make glaciated areas attractive to visitors

• There are a variety of activities for people to do: Skiing, hiking, climbing, mountain biking, etc.

• Boosts the local economy and provides a variety of jobs (directly and indirectly)

Not only this, there can often be wildlife photography and water sports.  

The Lake District is very popular as it has a mild climate and is easily accessible. In 2023, tourism in the Lake District generated £2.3billion, attracted 18 million tourists and created approximately 19, 000 jobs.

Quarrying in glacial landscapes

• Glacial erosion has exposed valuable sources of stone and minerals e.g. coal in upland areas

• Rocks such as granite and slate

• Slate provides building and roofing material for homes and granite can be used as pavement blocks and kitchen countertops

It also created employment either directly or indirectly in the area.

A lack of population also means there are fewer objections to quarrying when explosives are used.

Despite this, there are still many concerns over wildlife disruption, landscape scarring, water pollution and traffic congestion.

Honister slate mine in the Lake District not only quarries slate but now offers tourist opportunities into the history and importance of slate quarrying in the area.

Land use meaning

Land use is how the land is used for a specific type of activity.

Conflicts about land use can occur when…

there is a disagreement on how the land should be used. This is often between different stakeholders (people with an opinion or affected by the activity.

There is often conflict between economic activity and conservation (preserving the natural environment).

Farming potential conflicts

Farming can result in the clearing of trees in an area which increases flood risk and soil erosion.

Over grazing of animals can actually result in a loss of vegetation which results in soil erosion which causes water pollution.

conflict with conservationists

There is ongoing conflict in Swindale Valley where the RSPB has imposed a limit on the number of sheep to allow habitats to replenish

Potential solutions:

• Farmers can plan to rotate sheep around different areas on a rota

• Use less pesticides and fertilisers

Forestry potential conflicts

Forestry damages local habitats through deforestation.

Deforestation also increases the risk of flooding, soil erosion and landslides which can affect access for tourists, farmers and locals.

Potential solution: Engage local communities in the planning

Tourism potential conflicts

Tourism can lead to new infrastructure being built, changing the look of the area and increasing noise and traffic while it is built.

Tourists can also leave gates open in farming areas as well as damaging the stone walls used for farms.

Tourists also increase the amount of traffic congestion, litter, noise and pollution.

One example is footpath erosion.

There are often conflicts in the Lake District over the construction of zip lines. There was a proposal to build four more near the area of Windermere. The plans were dropped due campaigns from local people over conservation issues as it would threaten the landscape, threaten natural habitats and increase pollution. The military is also concerned that they pose a hazard to flying aircraft

Potential solutions: Invest tourist profit into conservation. Some roads have become pedestrianised or turned into a one way system

Farmers can limit access during certain times such as lambing season, National Parks have increased number of bins and recycling bins in the area

Quarrying potential conflicts

Quarrying can damage habitats and affect local wildlife.

They can also cause ‘landscape’ scarring which can made the area look less attractive.

Large transport vehicles can cause noise and air pollution as well as traffic congestion on small local roads.

Potential solutions: Enforce strict laws on noise, air and water pollution

Some roads have become pedestrianised or turned into a one way system

Avoid quarrying near main tourist sites

Engage local communities in the planning

Military potential conflicts

The military often completes training exercises in glacial landscapes as pilots can practice flying at high speeds around pyramidal peaks and into glacial troughs. However, the exercises are dangerous, can result in crashes and increase noise pollution in the area.

potential solutions:

Have designated training areas

Water management (reservoirs) potential conflicts

Building reservoirs in the local area for water storage can result in the flooding of large areas of land. The issue is the loss of farmland, it ruins the natural look of the landscape and it can lead to the loss of homes.

Potential solutions: Engage local communities in the planning

Hunting potential conflicts

Many areas are privately owned where hunting is allowed. Many nature lovers are opposed to hunting.

Hunting deer is also legal in the UK in certain times of year in order to control the population but only to those with licenses.

Renewable energy potential conflicts

Glaciated regions are an ideal place for the development of renewable energy sources. This is due to the lack of residents in the area.

Wind turbines are a popular choice due to the stronger and more reliable wind patterns through mountainous areas and large open areas of land for them to be built.

However, the look of them can ruin the landscape, the noise from turbines can reduce local house prices and they can affect the natural migration patterns of wildlife.

Potential solutions: Use new technologies that limit environmental impact of installing renewable energy, Engage local communities in the planning

What attracts people to the Lake District? Physical reasons

• Large lakes such as Lake Windermere for water sports, cruises and fishing

• Large mountains like Scafell Like for hiking and abseiling

• Other adventure sports such as rock climbing and biking

What attracts people to the Lake District? Human reasons

• It has inspired writers and poets

• Beatrix Potter lived near WIndermere and her home ‘Hill Top’ is now a National Trust attraction

• Scenic towns and villages such as Ambleside

Impacts of tourism in the Lake District (social)

• 20 million visited in 2018 which causes overcrowding for the 40 000 local population

• 83% of visitors arrive by car causing congestion on the narrow country roads

• House prices are high - 20% of property is holiday or second homes

• Jobs are seasonal and poorly paid

Impacts of tourism in the Lake District (economic)

• In 2023, tourism generated £2.3 billion

• Tourism provides employment for thousands of local people

• Traffic congestion slows down business communications

Impacts of tourism in the Lake District (environmental)

• The main tourist sites (honeypots) have overcrowding, footpath erosion and damage to verges from cars

• Pollution (oil, fumes) from vehicles and boats can damage ecosystems

• Walkers can damage farmland by trampling crops or leaving litter. Dogs can disturb sheep and cattle.

managing traffic congestion in the Lake District

The ‘Go Lakes Travel Programme’ is a £6.9 million initiative funded by the Department for Transport to encourage sustainable travel options. 

• Several dual carriageways have been built to improve access

• Developing public transport services and traffic management

• Developing integrated transport networks for walking and cycling with wheelchair access

managing footpath erosion in the Lake District

• repaired paths

• created steps

• re-planted native plants

responsible tourism in the Lake District

Responsible tourism is when tourists are encouraged to cause minimal damage in the area. 

Nurture Lakeland is a charity that encourages local businesses and tourists to donate to conservation projects in the area.