EPOW - Ecology Picture of the Week

Archaean Shield, Eastern Canada

Explanation:  It is mid-winter in the northern hemisphere, and flying over eastern Canada reveals a stark and startling landscape.  Or maybe "landscrape" might be a more appropriate coinage, because this is a land that was changed forever by monumental glaciers that ground landforms flat.

This is the Archaean (ancient) or Canadian Shield, so-named for the vast chevron-shaped area of very ancient rocks and endless glacial-scooped lakes.  Also called the Laurentian Plateau, this area includes much of eastern Canada, Greenland, and some of northeastern U.S.  

This area rose above sea level long ago and its Precambrian Era rocks (540 million to 4.5 billion years ago) were eroded over eons, most recently by Pleistocene continental glaciers and ice sheets.  

Much of the area's soil had been carried away by the glaciers, although boreal forest covers some of the shield area in the south, and tundra occurs in the north.  The area is mined for iron, nickel, copper, zinc, and other minerals, and some forestry is done ... but much of the area is sparsely inhabited by people and is home to bears, fox, caribou, and other wide-ranging wildlife.  They have room to roam, too, as the shield area extends some 4.4 million square kilometers (about 1.7 million square miles).  

And here are found fossils of antiquity ... ancient bacteria and algae over 2 billion years old.  Truly a land of antiquity.  

The Canadian Shield area contains thousands of glacier-carved lakes.

Few high points jut above the average elevation of
300-500 meters (1,000-1,600 feet).

Glaciers scraped off soil and exposed massive layering
and folding of the rocks below.

Frozen lakes and rivers make the area inhospitable, but is
home to much wildlife.

The Canadian Shield -- the ancient core of North America!