Physical Geography

Glacial erosion is a very powerful force in the evolution of landscapes. At the moment about 10 percent of the earth's surface is subject to glaciation, but it is estimated that in the past upto a third of the surface was subject to glacial activity. In consequence there is evidence of glaciation found in many areas that now have much milder climates, as well as in the remaining high mountain areas of the continents where temperatures allow snow to remain all year round.

The size of the features produced by erosion varies considerably, from tiny scratches to massive corries, mountain tops and valleys. In this lesson you will look at the most common features and investigate how they are formed.

We will look at the following landforms:
Corries
Aretes and Pyramidal Peaks
Hanging Valleys
Ribbon Lakes
U Shaped Valleys
Striations, Roche Moutonnee and Crag and Tail

 

Activity  Read the articles about each of the features listed above, and make sure that you understand what each feature looks like, and how it is formed. Once you understand each feature, make brief notes on each, explaining its origins and appearance. In an examination you may be asked to identify some of these features on a map or sketch drawing. To help you cope with this, try to answer the following... 1. What pattern would the contour lines on a map form to represent a corrie, a pyramidal peak and a hanging valley ? 2. List the features in the order in which you might expect to see them in a trip from the top of a mountain to the bottom 3. How would you tell the difference between a U shaped and a V shaped valley on a map? 4. Put these features in the correct order of development in a glacial landscape, so that they start with the first feature to be formed, and end with the last one...there may be some arguements about where to place a few of these, so discuss it and explain your choices. Valley Glaciers, Pyramidal Peaks, Snow Patches, Aretes,Nivation Hollows, Corries, Niche Glaciers, U Shaped Valleys, Ribbon Lakes.

 
 

Further Activities You will now have to carry out some research of your own... a) Find a map of an area that has been glaciated in the past. It needs to be at a scale that will show landforms clearly, so use a 1:50,000 or 1:25,000 scale. Try to identify all the erosional features we have discussed, and select the best examples to keep as case studies to use in the exams. b) Study a glaciated area and find out how the landforms produced by glacial erosion have been used by man for communications, water supplies and tourism. Make brief notes showing which features are linked to which activities, and explain why they are choosen for these activities.