A glacier is a mass of ice that slides and flows downhill under its own weight. They are found at high altitudes, although at very low temperatures, glaciers are not likely to be found due to how they are formed.
Glacier formation[edit | edit source]
First the climate deteriorates so that the snow that has fallen in Winter remains there all year round.
Over many Winters, the successive layers of snow build up to compress the layers underneath. This process is helped is not too cold.
Eventually, the air passages in the snow get closed off, and it turns to Firn or Névé.
When the pressure from the snow above becomes even greater, the Firn/Névé turns into Glacial Ice.
Types of glacier[edit | edit source]
Mountain Glaciers- A mountain glacier formed from icesheets that can span several mountains or even a mountain range. These mountain glaciers can be found in Antartica, the Andes, Himalayas and Northen Canada.
Valley Glaciers- These glaciers originate from either icesheets or mountain glaciers and flow down valleys.
How glaciers erode[edit | edit source]
There are two main ways that glacier erodes: abrasion and plucking.
Abrasion is when the rocks carried by the glacier, rubs against the ground and acts like sandpaper, smoothing the surface.
Plucking occurs when water from the glacier freezes onto rocks and then, as the glacier moves, the rocks breaks free from the ground.
Land formations created by glaciers[edit | edit source]
U-Shaped Valleys (also known as glacial troughs)
U-Shaped valleys are formed because as the glacier moves down the valley, unlike rivers that meander around, glaciers just plough through. Overdeepened by erosion and dammed by terminal moraine, they may contain ribbon lakes.
Corries (also known as cirques or cwms)
Moraine (terminal, medial, lateral), boulder clay / till
There are good examples of all these features in the Lake District.