How was the Canadian Shield formed?

The Canadian Shield is an uplifted plateau of dense and ancient rocks. Its center is Hudson Bay, its rims reach to Greenland, Alaska and south to the Great Lakes. When the earth was young, this region was a shallow sea where countless muddy streams dumped their silty debris for countless years. At last, the weighty sediments began to heave up into a vast mountain system.

This was more than 2,000 million years ago. .All this time, the weather has been waging endless warfare to wear down those ancient mountains. Now all that remains is a vast shield of dense rock which is actually the roots of a massive mountain system which towered in the Northern Hemisphere when the world was young.

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