An Teallach: a glaciated mountain
This piece of work is aimed at 14-18 year old pupils or those interested in developing a knowledge and understanding of the physical geography of mountain glaciation. Access to Ordnance Survey Landranger series sheet 19 would be helpful to further this study and is needed for some of the tasks. Tasks are set at two levels with those in B being more demanding.
Photograph 1 (032799, northeast)
A general view of An Teallach, a mountain massif extending over around 50 square kilometres in Wester Ross. The corrie in the centre of this photograph is less well developed than those beyond the ridge seen because of the southerly aspect of this side of the mountain.
Task A
1.1 Make a quick sketch of the photograph and, using the O.S. map, identify the following locations: Sgurr Creag an Eich, Sgurr Fiona, Sàil Liath, Loch na Sealga, Abhainn Srath na Sealga.
1.2 Add the following terms to the sketch: pyramidal peak, corrie, arête, side of U-shaped valley, ribbon loch.
Task B
1.3 Explain the final sentence in the text.
Photograph 2 (096833, west)
Toll an Lochain, the corrie in grid square 0783, looking from the escarpment below which the glacier moving out of the corrie would have flowed. The lip of the corrie prevents the lochan being seen.
Task A
2.1 Label a sketch of this photograph with the following: deep hollow eroded by a glacier, cliffs of the corrie's backwall, lip of corrie, corrie lochan (behind lip), direction of flow of glacier.
2.2 Draw a sketch cross-section from Sgurr Fiona to 090831 and add the above labels to it.
Task B
2.3 Draw a sketch cross-section from Sgurr Fiona to 090831, add what this would have looked like during valley glaciation and add labels to explain the process of erosion.
Photograph 3 (069843, southeast)
Loch Toll an Lochain from the highest point of An Teallach.
Photograph 4 (069843, south)
Lord Berkeley's Seat and Corrag Bhuidhe, the ridge to the south of Toll an Lochain.
Task A
4.1 What evidence is there on the map that this would be a dangerous ridge to walk?
Photograph 5 (064836, southeast)
Another view of the ridge between Sgurr Fiona and Sàil Liath. This treacherous arête separates Toll an Lochain from the deep U-shaped valley in which Loch na Sealga is found.
Photograph 6 (074840, north)
Weathered rock on Glas Mheall Liath.
Task B
6.1 Considering that this is sandstone, what forms of weathering have acted on these rocks to produce this feature.
Photograph 7 (064836, southwest)
Task A
7.1 Explain, with the aid of a diagram, the formation of this feature.
Photograph 8 (040851, north)
View of Coire Mòr an Teallaich. Although the northern part of the mountain is composed of the same rock, Torridonian Sandstone, as the southern part, it is much less rugged and the tops here are more rounded. This corrie is the largest on An Teallach, indeed its name means 'the big corrie of An Teallach', but it is less spectacular than those to the east. Little Loch Broom is visible in the distance beyond where the Allt Airdeasaidh drops steeply into the broad, deep valley in which that loch lies.
Photograph 9 (069843, northwest)
A further impression of Coire Mòr an Teallaich may be gained from this photograph. The corrie is to the left of the view with The Minch and the Outer Hebrides in the distance.
Photograph 10 (069843, north)
This last view, taken from the summit again, covers the north of the massif. To the immediate right will be seen part of the more northerly of the deep corries. Beyond the ridge on the right is another, shallower corrie.
Task B
10.1 'An Teallach is an example of a glaciated landscape.' Referring to the map, describe in detail the evidence for glaciation.
Additional questions
Task A
A.1 Look again at photograph 7 and give a detailed description of the landscape.
Task B
A.2 Discuss the opportunities and limitations provided by this landscape for economic activity.
A.3 On tracing paper over the map of An Teallach, indicate the likely direction of movement of glaciers.