Glaciation Flashcards
What is an ice age
When there is a period of time when thick ice sheets cover vast areas of land as the global temperature stays below 0°C
How long ago did ice cover 30% of land in the world
18,000 years ago
What was the temperature of the last ice age
The temp stayed below 0 which allowed the ice to remain on the land all year.
What is a glacier
A large body of ice moving down a slope or over a wide area of land.
Glaciers once covered large areas of the earth and shaped the landscape around them. The legacy of ancient glaciers lives on for example, in areas such as the Lake District.
What’s an example of a glacier in Europe
The Mer De Glace glacier in the French alps
What processes does glaciation affect
Erosion
Transportation
Deposition
How does a glacier form
They form in very cold places. Lots of snow falls but not all of it melts. This means that a lot of different layers of snow lie on top of each other.
The bottom layer of the snow got compressed by the top layers. This means the air is pushed out and the snow turns into ice forming a glacier.
The glacier gradually moves down the slope under the force of gravity.
What’s the difference between an ice sheet and a glacier
Masses of ice which cover large areas of a continent are called ice sheets.
Those which occupy mountain valleys are called valley glaciers
What European countries were covered in ice during the last ice age
Iceland
All of Ireland
Norway
Sweden
Finland
Denmark
What are interglacials
We call times with large ice sheets “glacial periods” (or ice ages) and times without large ice sheets “interglacial periods”
What’s another name for ice age
Glacial periods
What % of earths surface is covered with glaciers today
10%
Where are the biggest glaciers currently found
Antarctica and Greenland
Where can smaller glaciers be found
At high altitudes in various mountain ranges in the lower, middle and higher altitudes.
E.g. Mont Blanc, Canadian rockies and the alps
What does the glacier system consist of
Inputs, transfers (flows) , stores and outputs .
In the same way as a river
Tell me about inputs
Inputs come from avalanches along the sides of the glacier, but mainly from precipitation as snow.
Tell me about storage/stores
Over time snow accumilates and is compressed into ice. The water hold in storage is the glacier.
Tell me about flows
Under the force of gravity the glacier
flows downhill.
Tell me about outputs
Meltwater is the main output from the glacier, along with evaporation.
Accumulation + ablation
The balance between inputs and out puts leads to accumlation and ablation
Accumulation
In the winter, more is added to the glacier system than is lost. This happens near to the land of a glacier that leads to a zone of accumilation. This can cause a glaier to advance.
Accumilation = inputs > outputs