<P> The current surface expression of the Shield is one of very thin soil lying on top of the bedrock, with many bare outcrops . This arrangement was caused by severe glaciation during the ice age, which covered the Shield and scraped the rock clean . </P> <P> The lowlands of the Canadian Shield have a very dense soil that is not suitable for forestation; it also contains many marshes and bogs (muskegs). The rest of the region has coarse soil that does not retain moisture well and is frozen with permafrost throughout the year . Forests are not as dense in the north . </P> <P> The Shield is covered in parts by vast boreal forests in the south that support natural ecosystems as well as a major logging industry . This boreal forest area includes ecoregions such as the Eastern Canadian Shield taiga that covers northern Quebec and most of Labrador, and the Midwestern Canadian Shield forests that run westwards from Northwestern Ontario . Hydrographical drainage is generally poor, the soil compacting effects of glaciation being one of the many causes . Tundra typically prevails in the northern regions . Many mammals such as caribou, white - tailed deer, moose, wolves, wolverines, weasels, mink, otters, grizzly bear, polar bears and black bears are present . In the case of polar bears (Ursus maritimus) the Shield area contains many of the denning locations such as the Wapusk National Park . </P> <P> The Canadian Shield is one of the world's richest areas in terms of mineral ores . It is filled with substantial deposits of nickel, gold, silver, and copper . Throughout the Shield there are many mining towns extracting these minerals . The largest, and one of the best known, is Sudbury, Ontario . Sudbury is an exception to the normal process of forming minerals in the Shield since the Sudbury Basin is an ancient meteorite impact crater . Ejecta from the meteorite impact was found in the Rove Formation in May 2007 . The nearby, but less known Temagami Magnetic Anomaly, has striking similarities to the Sudbury Basin . This suggests it could be a second metal - rich impact crater . </P>

What is the climate in the canadian shield region
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