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GLACITATION. GLACIERS Approximately 10% of the earth’s land surface is covered by glaciers. 20 000 years ago 25-30% of the earth’s land surface was covered.

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Presentation on theme: "GLACITATION. GLACIERS Approximately 10% of the earth’s land surface is covered by glaciers. 20 000 years ago 25-30% of the earth’s land surface was covered."— Presentation transcript:

1 GLACITATION

2 GLACIERS Approximately 10% of the earth’s land surface is covered by glaciers. 20 000 years ago 25-30% of the earth’s land surface was covered by ice.

3 GLACIERS Most of the world's glaciers are found near the Poles, but glaciers exist on all of the world's continents, even Africa. Glaciers require very specific climatic conditions. Most are found in regions of high snowfall in winter and cool temperatures in summer. These conditions ensure that the snow that accumulates in the winter isn't lost during the summer.

4 Continental Glaciers A dome-shaped mass of glacier ice that covers surrounding terrain. Larger and thicker than Alpine Glaciers

5 Alpine Glaciation A mountain glacier whose flow is confined by valley walls. Most middle and upper latitude mountain ranges have been shaped by Alpine Glaciers.

6 Glaciers A glacier forms when snow accumulates over time, turns to ice, and begins to flow outwards and downwards under the pressure of its own weight.

7 Glaciers In polar and high-altitude alpine regions, glaciers generally accumulate more snow in the winter than they lose in the summer from melting, ablation, or calving. If the accumulated snow survives one melt season, it is considered to be firn.

8 Glaciers The pressure created from the overlying snow compacts the underlying layers, and the snow grains become larger ice crystals randomly oriented in connected air spaces. As compression continues and the ice crystals grow, the air spaces in the layers decrease, becoming small and isolated. This dense glacial ice usually looks somewhat blue.

9 Glaciers The erosive power of glaciers is incredible! Glacier ice can pick up material and move it 100’s of kilometers.

10 Abrasion Erosive scraping and polishing The Canadian Shield was formed as the result of abrasion “Finger Lakes” Great Lakes

11 Glacial Features Continental Fjords Moraines Erratics Kames Kettles Drumlins Spillways Alpine Cirques Horn Hanging valleys Lateral moraines Medial moraines Terminal moraines Skerries

12 Features of Glaciated Landscapes

13 GLACIAL FEATURES

14 Melting Himalayan Glaciers Video:http://video.google.ca/videosearch?q=Nature+ Glaciated+landscape&hl=en&emb=0&aq=f#q=meltin g+himalayan+glaciers&hl=en&emb=0 Video:http://video.google.ca/videosearch?q=Nature+ Glaciated+landscape&hl=en&emb=0&aq=f#q=meltin g+himalayan+glaciers&hl=en&emb=0 Melting Artic Glaciers Spell Disaster Video: http://www.youtube.com/watch?v=1Q53ikp947E http://www.youtube.com/watch?v=1Q53ikp947E Global Warming Creates World's First Climate Change Refugees Video: http://www.youtube.com/watch?v=NHtqe2nhXiM http://www.youtube.com/watch?v=NHtqe2nhXiM


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