The Great Lakes Were Formed By?
By any measure, the Great Lakes, located in the upper Midwest region of the United States, primarily along the border between Ontario, Canada and the state of Michigan (along with portions of the states of Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York), are, well, pretty great. Lake Superior just by itself is the second largest lake in the world by area, Lake Michigan is the largest lake located entirely within a single country, and collectively they (with the remaining lakes, Huron, Erie, and Ontario) are the largest group of fresh water lakes on Earth, containing 21 percent of the world’s surface fresh water by volume.
With that in mind, if you imagined the force that created the Great Lakes to be equally as impressive as the bodies of water it left behind, you wouldn’t be wrong at all. The enormous lakes, with a total volume of 5,439 cubic miles (measured at the low water datum), were created through an enormous force–the Laurentide ice sheet. During the last ice age when enormous glaciers crept down over North America and later retreated, they scooped out the huge areas of land that are now the Great Lakes. That seems almost incredulous, but the glacial sheet that carved the lakes out was so vast it covered millions of square miles and was up to two miles thick at its thickest point.