<P> The Canadian Shield , also called the Laurentian Plateau , or Bouclier canadien ( French ) , is a large area of exposed Precambrian igneous and high - grade metamorphic rocks ( geological shield ) that forms the ancient geological core of the North American continent ( the North American Craton or Laurentia ) . Composed of igneous rock resulting from its long volcanic history , the area is covered by a thin layer of soil . With a deep , common , joined bedrock region in eastern and central Canada , it stretches north from the Great Lakes to the Arctic Ocean , covering over half of Canada ; it also extends south into the northern reaches of the United States . Human population is sparse , and industrial development is minimal , while mining is prevalent . </P>
what is the main industry in the canadian shield
mining