Despite all the talk about global warming, another ice age in Britain is not impossible. There is still permanent ice in the Alps and in Iceland, and if parts of Scotland were only 200 m higher they’d have permanent snow.

Use the diagrams below of a mountain in Britain to put the statements in order.

• Many snowfalls add to this build-up.
• The mountain has three streams running down from the peak; it always gets a lot of rain.
• Eventually snow covers the whole mountain, with thick ice in the deep hollows.
• The ice at the bottom of these snow-filled hollows gets thicker and thicker; gradually, like thick treacle, it slides down to valleys below, joined by the ice flow from other hollows.
• Instead of rainfall, the mountain now gets snowfall.
• South-westerly winds blow snow onto sheltered parts of the mountainside.
• Away from the sun, snow builds up and becomes deep; pressure from this thick layer turns the snow underneath into ice.
• The climate becomes colder.
• Frosts constantly attack the slopes all around and turn the gentle slopes into steep ridges.
• Snow in south-facing hollows tends to melt in the brief summer, but in north-facing hollows it persists through the year.

Activity 2: Glacial Erosion

Dramatic glacial troughs like Bealach na Baa in north-west Scotland, and corries like Llyn Cau at Cader Idris in north Wales, are produced by glaciers removing enormous quantities of rock and soil.

Find out the meaning of the terms below using your textbooks; then place the labels in the right place on the diagram below.

1. ‘Plucking’: removes huge blocks from back wall.

2. Abrasion: sharp rocks, embedded in ice, erode the floor by filing it down.

3. Rotation: the corrie glacier slides down and round in its rocky basin.

4. Pressure from new snow.

5. Less pressure, because less snow falls here.

6. Rock lip forms, because corrie glacier is sliding upwards here and not eroding much.

7. After Ice Age, corrie glacier leaves a basin-shaped hollow, often with tarn or corrie lake in floor of hollow.

8. Huge valley glacier fed by several corrie glaciers.

9. After Ice Age, valley glacier leaves a glacial trough and often a long, narrow ‘ribbon lake’.

10. Plucking under valley glacier.

11. Abrasion under valley glacier.

12. Rock bar at end of valley glacier.

13. Valley glacier thinner (farthest away from snow and ice supply, so less erosion).

14. Corrie glacier.

Click here for the correct answers

Activity 3: Glacial Deposition — a Case Study in the York Area

Look at the website:

http://freespace.virgin.net/paul.brelsford/History/YorkRelief.html

(Moraines around York.)

In your book, make a case study using these headings:

• Types of moraine found near York.
• Sketch map to show their location.
• Height and length of key moraines.
• Origin of these features.