Wednesday, August 12, 2009

Ice Age

Today the north pole and the south pole are the biggest expenses of ice we see on earth,But what we today see is the only one-third of the ice on earth.Millions of years ago large part of Canada,Greenland and northen Europe were covered with huge expenses of ice.In the last few millions years there occured many such periods known as ice ages.In last 8,50,000 years there have been ten ice ages,with the last occuring about 12,000years ago.Even scientists also dont know why these ice ages occured.These may have been caused due to the path of the earth around the sun or changes in the angle of axis.Therotically it is said that there have been warm periods between these ice ages and we may be living in the warm periodbefore the onset of the next ice age.These theory however has not been proven.
It is believed that during the ice ages the snow accumilated in large quantities and sheets of ice extended and formed over north america and europe.In the warmer periods between the ice ages large quantities of snow melted glaciers daposited huge quantities of moraine [rocks and gravel] in many areas,large portion of land was submerged in water beacause in the rise of sea waterlevls,rivers two alterated their courses and flooded many areas.Today if all the ice was to be melt then the oceans and seas would rise by 70 metres and most areas currently at this sae lavel,Netherland and Denmark for example would be flooded.

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