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South Wirral Geography - Ice on the Land
Transcript of South Wirral Geography - Ice on the Land
How ice forms
Different types of Moraine
Cwms, Aretes and Pyramidal Peaks
U Shaped Valleys and Ribbon Lakes
Features created by deposition
Glaciers form when snow is turned into ice. Each year lots of snow builds up, if it cant melt in the summer (temperatures too low), then the snow in the next winter builds up on top. Over lots of years, there will be a lot of snow building up and the weight of all of this snow begins to compress the air from the bottom layers. This removal of air from the snow creates neve and eventually if enough air is removed then ice is born!
I strongly urge you to watch this whole 59 min program about Ice!
Terminal Moraine - rocks dropped at the end of the glacial ice
Recessional Moraines - when ice retreats (due to higher temperatures), the terminal moraines move backwards, recessional moraines are the collective term for different piles of rock.
Lateral Moraines - rocks on the side of the glacier - they have rolled down from the mountain slopes and settled on the sides
Medial Moraines - when two glaciers merge together, the lateral moraines get pushed together and end up in the middle of the ice.
Supra glacial - on top of the ice
Englacial - in the ice
Sub Glacial - under the ice
Let Dr Iain Stewart show you...
Coniston Lake in Cumbria is an example of a ribbon lake - used for setting speed boat records due to its length.
Ribbon Lakes are formed in the base of U shaped valleys, the ice creates a hollow, where water collects. They are long and thin - often a bit like a slug shape.
U shaped valleys - above the Lauterbrunnen in Switzerland and below Yosemite Valley
Explanation of U shaped valley formation (some bits not relevant, but other bits are)
An Arete, the section of land between two cwms.
Cwm Idwal in Snowdonia - there is a tarn in the bottom of this circular cwm, the steep back wall and flat base are typical features of the cwm. Remember they might be referred to as a Corrie (Scottish) or Cirque (French) in an exam...
The Matterhorn in the Swiss section of the Alps, is a great example of a pyramidal peak - there are 3 cirques on the different faces of the mountain. Use Google Earth to go and have a look at it!
No-one knows how drumlins are made - you will not be asked to explain how they are made in an exam - all you need to remember is that they are features created by deposition of moraines. It is likely that the sub-glacial moraines are scraped from the underside of the ice and then shaped into these distinctive shapes. Think about the play-dough activity we did in class.
How to be prepared for an Avalanche
(watch the video and you'll always be safe!)
Loose Powder Avalanche
Search YouTube for videos of avalanches and try to work out if they are slab or loose powder avalanches...
This is the same topic, organised in a different way - this can be downloaded from the Geography GCSE Moodle page
Learn these things and ace the test!
They can't ask you anything not on here - check what you understand or don't understand then do something about it