Work of Ice - • A glacier is a mass of moving ice...

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Work of Ice Every 200-250 million years, climatic activity leads to falls in temperature of over 5 degrees centigrade. These periods of great ice activity are known as Ice Ages . The most recent is the Pleistocene period of the Quaternary era , which began 2 million years ago. The earth only became warmer during the last 20,000 years. Reasons for fall in Earth's temperatures Movement of tectonic plates leading to an increase in the altitude at constructive margins. Changes in ocean currents Variations in sunspots changing the amount of radiation received by the earth Changes in level of atmospheric CO 2 . Glaciation Glaciation is the work of ice in a landscape.
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Unformatted text preview: • A glacier is a mass of moving ice confined in a valley. • When air temperature falls to sub-zero, water vapor condenses and freezes to form snow . • If the snow doesn't melt, a permanent snow covering is formed known as a snow line . • If the accumulation of snow continues, the snow hardens into ice crystals separated by air spaces. Due to pressure, ice melts and water flows into the air spaces and re-freezes. This turns the snow into a granular mass known as a ne've or firn . • Finally, all the air spaces disappear and a glacier is formed. Ice blocks may break off to form icebergs ....
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This note was uploaded on 12/04/2011 for the course BSC 1085 taught by Professor Staff during the Fall '09 term at Broward College.

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