Ice on the Land Flashcards
How long ago did the last glacial period end?
100,000 years ago
What was the name of the last ice age?
The Pleistocene
How much of the earths land surface is currently covered by ice?
10%
What three types of evidence are used to identify past temperature changes?
Chemical
Geological
Fossil
Define the term accumulation
The input of snow and ice into a glacier
What is the zone of ablation?
You get more ablation than accumulation in the lower part of a glacier so it’s called the zone of ablation.
What happens when a glacier has a positive glacial budget?
When accumulation is greater than ablation. The glacier gets larger and the snout advances down the valley.
Why does a glacier retreat in summer?
Because there is a negative glacial budget due to lack of accumulation and ablation due to high temperatures.
Give an example of a retreating glacier
The Rhone Glacier in the Swiss Alps. 7.8km long. It’s been retreating since the 19th century.
Give 3 sources used as evidence of glacial retreat
Pictures
Monitoring data
Amount of meltwater
What is rotational slip?
At the top end of a glacier the ice doesn’t move in a straight line - it moves in a circular motion called rotational slip. This can erode hollows in the landscape and deepen them into bowl shapes.
Explain what freeze thaw weathering is
Where water gets into cracks in rocks and then freezes and expands putting pressure on the rock. The ice then thaws, releasing the pressure. If this process is repeated it can cause pieces of rock to fall off.
What is a corrie?
Carries begin as hollows containing a small glacier. As the ice moves by rotational slip, it erodes the hollow into a steep stored armchair shape with a lip at the bottom end. When the ice melts it can leave a small circular lake called a tarn.
How does a pyramidal peak form?
It is formed when three or more back to back glaciers erode a mountain.
What is a pyramidal peak?
A pointed mountain peak with at least three sides. E.g Snowdon in Wales
Explain how a hanging valley forms.
They are formed by smaller glaciers (tributary glaciers) that flow into the main glacier. The glacial trough is eroded much more deeply by the larger glacier so when it melts the valleys are left at a higher level.
What is bulldozing?
Glaciers can move material (such as rocks and earth) over very large distances - this is called transportation. The material is frozen in the glacier, carried on its surface or pushed in front of it. It’s called BULLDOZING when the ice pushes loose material in front of it.
Describe what a drumlin looks like.
They’re round, blunt and steep at the upstream end, and tapered, pointed and gently sloping at the down stream end. Like a tear drop from birds eye view.
How would you identify a pyramidal peak on a map?
A pyramidal peak has tightly packed contour lines that curve away from the central high point. If you find this you’ll find the arêtes and carries around it.
Describe what a glacial trough looks like on a map.
Glacial troughs are flat valleys with very steep sides. There are no contour lines on the bottom of the valley but they’re tightly packed on the sides.
What does a ribbon lake look like on a map?
Long straight and thin
Give one reason why areas covered in snow and ice are fragile environments
They are easily damaged and difficult to manage.
There’s only a short growing season.
Decay is slow because of the cold so litter and pollution remain in the environment for a long time.
Give two social impacts of tourism on areas covered by ice and snow
Increased numbers of people.
More jobs.
Tourists can trigger avalanches.
Describe two environmental impacts of tourism on areas covered in snow and ice.
Soil erosion.
Glacial landforms are eroded.
Increased noise, pollution and litter.
Developments have a visual impact on the environment.
Give an example of an area in the Alps used for winter sports and sightseeing of glaciers
Chamonix in eastern France at the foot of Mont Blanc in the Alps.
Give examples of management strategies used in Chamomix
Avalanche barriers.
Free public transport.
Reduced energy use.
Name an industry affected by glacial retreat
Winter tourism
Give one social impact of glacial retreat
Unreliable power supply.
Water supply reduced in some places.
Services shut down.
Ice will no longer be available for recreational use.
Give one economic impact of glacial retreat
One the glacier has completely melted, the amount of meltwater decreases. This means industries that rely on a supply of melt water will make less money and could shut down.
