Red Tarn, Lake District They are all features of glacial erosion

Transcription

1 Ribbon Lake Lake Windermere, Lake District Arete Striding Edge, Lake District Pyramidal Peak Corrie & Tarn 4 Matterhorn, Switzerland Red Tarn, Lake District They are all features of glacial erosion

2 KEY IDEAS & QUESTIONS To identify and describe landforms created by glacial erosion To explain how a landform of glacial erosion is formed a corrie and tarn.

3 3/4 Identify and describe a corrie, tarn, arete and pyramidal peak 5/6 Identify and describe most of the following features; corrie, tarn, arete, pyramidal peak, truncated spur, hanging valley, U-shaped valley, ribbon lake and misfit stream. Give a basic explanation of how a corrie and tarn are formed. 7+ Identify and describe all of the following features with accuracy and detail; corrie, tarn, arete, pyramidal peak, truncated spur, hanging valley, U-shaped valley, ribbon lake and misfit stream. Give a clear explanation of how a corrie and tarn are formed, using key terminology including freeze-thaw, plucking and abrasion.

4 We are studying a topic about glaciers. These 3 photos are of glaciated landscapes. What s the problem? There s no ice!

5 Glaciated landscapes in the UK were shaped about 20,000 years ago in the last Ice Age. When the ice melted a new landscape was revealed.

6 Before glaciation During glaciation After glaciation

7 The study of glaciation is all about imagining what the ice was doing when there were glaciers here 20,000 years ago.

8 Match the correct labels to the diagram

9 Pyramidal peak Corrie Arete Ribbon Lake Tarn

10 A tarn is a circular lake formed at the bottom of a corrie when a glacier melts A ribbon lake is a long, narrow body of water A pyramidal peak is a pointed mountain peak with at least 3 sides A corrie is an armchair-shaped hollow, high on a mountain, with steep back and side walls An arête is sharp mountain ridge

11 Pyramidal peak Corrie Arete Ribbon Lake Tarn

12 Tarn Pyramidal peak Hanging valley Corrie Truncated spur Arete Ribbon Lake Misfit stream U-shaped valley

13 Ribbon lakes are long, thin lakes that form after a glacier retreats. They form in hollows where softer rock was eroded more than the surrounding hard rock. U-shaped valleys (also called glacial troughs) are steep sided valleys with flat bottoms. They start off as a V-shaped river valley, but change to a U-shape as the glacier erodes the sides and bottom making it wider and deeper. When the ice melts in a corrie it leaves a small circular lake called a tarn. Hanging valleys are valleys formed by smaller glaciers (called tributary glaciers that flow into the main glacier. The U- shaped valley is eroded much more deeply by the larger glacier, so when the glaciers melt the tributary valleys are left at a much higher level. A pyramidal peak is a pointed mountain peak with at least three sides. It is formed when three or more back to back glaciers erode a mountain.

14 Corries begin as hollows containing a small glacier. As the ice moves it erodes the hollow into a steep armchair shape with a lip at the bottom end. Truncated spurs are cliff-like edges on the valley side formed when ridges of land (spurs) that stick out into the main valley are cut off as the glacier moves past. An arête is a narrow steep sided ridge formed when two glaciers erode in parallel valleys. The glaciers erode the sides of the valleys, which sharpens the ridge between them, giving it a jagged profile. Misfit rivers meander through the wide U-shaped valley floor. They look out of place as they did not erode the valley as they are so small. They formed after the glacier melted.

15 Tarn Pyramidal peak Hanging valley Corrie Truncated spur Arete Ribbon Lake Misfit stream U-shaped valley

16 Match the pictures 1-5 to the correct OS map A to E

17 1 C

18 Hanging Valley Truncated spur B Truncated spur 2

19 3 E Misfit stream Ribbon lake

20 4 A

21 5 D U-shaped valley

22 Focus on corries and tarns

23 1. Put the cards in the correct order to explain the formation of a corrie and tarn 2. Where do you think each piece of information would be labelled on this diagram?

24 Snow collects in a shallow hollow, turns into ice and then moves downhill. Freeze-thaw weathering above the glacier breaks off pieces of rock which fall onto the glacier. Plucking behind the glacier steepens the back wall. Abrasion under the ice deepens the hollow. A rock lip forms where there is less erosion. It may be covered with moraine deposited by the glacier. When the ice melts, a bowl shape is left in which a tarn may form.

25 Freeze-thaw weathering above the glacier breaks off pieces of rock which fall onto the glacier. Plucking behind the glacier steepens the back wall. When the ice melts, a bowl shape is left in which a tarn may form. Snow collects in a shallow hollow, turns into ice and then moves downhill. Abrasion under the ice deepens the hollow. A rock lip forms where there is less erosion. It may be covered with moraine deposited by the glacier.

26

27 Stick the labels onto the correct place on the diagram provided.

28 Make a copy of the diagram in your book and stick the labels onto the correct place on the diagram.

29 Make a copy of the diagram in your book and use the card sort to help you add labels to explain the formation of a corrie and tarn.

30 KEY IDEAS & QUESTIONS To identify and describe landforms created by glacial erosion To explain how a landform of glacial erosion is formed a corrie and tarn.

31 3/4 Identify and describe a corrie, tarn, arete and pyramidal peak 5/6 Identify and describe most of the following features; corrie, tarn, arete, pyramidal peak, truncated spur, hanging valley, U-shaped valley, ribbon lake and misfit stream. Give a basic explanation of how a corrie and tarn are formed. 7+ Identify and describe all of the following features with accuracy and detail; corrie, tarn, arete, pyramidal peak, truncated spur, hanging valley, U-shaped valley, ribbon lake and misfit stream. Give a clear explanation of how a corrie and tarn are formed, using key terminology including freeze-thaw, plucking and abrasion.

32 Something beginning with Plenary T C P A Tarn Corrie Pyramidal Peak Arete

33 T20 Independent Independent Learning Opportunity T20 Flexible 1. Watch: Everest (2015). How many features of glaciation from today s lesson can you spot? Write down a list. What did you think of the film? 2. Research: Snowdonia in North Wales is a well-known upland glaciated area. Go online and research into the area. 3. Explore: Either Snowdonia or The Lake District. Make a photojournal or tweet your glacial pics 2 can be done as a PowerPoint, on paper, a poster or fact file Bring your work in to gain an ILO credit Have this ready to hand in for: