The use and abuse of Snowdonia, a glaciated upland region.

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The use and abuse of Snowdonia, a glaciated upland region


  Glaciers have had a major effect on the way the landscape in North Wales has been shaped.  The Snowdonia National Park in North West Wales (not far from Anglesy) has many features including ribbon lakes, striations, u-shaped valleys and misfit rivers, truncated spurs and hanging valleys, pyramidal peaks and aretes which were been formed in the ice age by glaciers.  The national park even includes a cwm or a corrie lake, Cwm Idwal.  These features have many uses most of which are good as they bring many job opportunities to the region and various other things but also brings Snowdonia its fair share of problems.  

The glacial features of Snowdonia

  Glaciers have had a major effect on the landscape of North Wales and towards the east of North Wales this is no exception.  In the Snowdon National park is Snowdon a pyramidal peak, it is the highest mountain in England and Wales at 1085 metres.  The Snowdonia National Park has everything, breathtaking aretes, u-shaped valleys and various cwms which are all leading off from its summit.  Glacial deposition has left its mark as well as there are many lakes that have formed where valleys have been dammed or where the ground has been made uneven by moraine.    

Corrie lakes or Cwms

  This is Cwm or Llyn Idwal in the Snowdonia National Park


 This is a bowl-shaped hollow with a very steep back but has a shallow lip and is deep and round.  This is how cwms formed in the beginning of the ice age

1. Snow collected in hollows

2. It compacted and turned into ice

3. Moved downhill under its own weight

4. Freeze thaw, abrasion and plucking, steepen corrie sides and deepen floor

5. Lip forms at the edge of the cwm where there is less erosion

6. As the glacier passes over the lip, tension causes fractures called crevasses

7. Over time the cwm filled up with water and became a lake

U-shaped valley and Misfit River

  This is Nant Ffrancon

  This is a U-shaped valley with a small river called Nant Ffrancon winding its way through the valley floor, this type of river is called a misfit river as it’s a very small river that looks out of place on a big valley floor.  The reason for this is when a glacier fills such a valley like this it deepens, widens and straightens, cutting off all the spurs and the valley now becomes known as a glacial trough.  The resulting shape is now a straight, deep, wide, flat floored, steep-sided, trough-shaped glacial valley.  The spurs are then cut off and are called truncated spurs.  The river which is left over after ice has melted, now looks far too small for its deep, wide valley and that is why it is called a misfit river.  There is also moraine on the sides of the valley, this is called lateral moraine as it is carried at the sides of the glacier.

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  Snowdon is a pyramidal peak which means that three or more cwms have eroded backwards into the same mountain (Snowdon).  Aretes radiate from this central peak.

Uses of the glacial features of Snowdonia


  Snowdon itself can be used to do an number of things Cycling, camping, walking, climbing.  Cwm Idwal could be used as a place water sports such as canoeing, windsurfing, sailing etc.  The U-shaped valley of Nant Ffrancon could be a great photo or painting opportunity.  Many of the attractions are related to the natural ...

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