Mar 16

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Of Ice and Mittens, Or, How the Great Lakes Formed

What does a long-gone glacier have to do with Michigan being shaped like a mitten? Pretty much everything. Listen up:

(via NOAA)

Forget winter! The Great Lakes had a pretty frozen beginning! (via NOAA)

Let’s go back about 14,000 years to what’s now the Great Lakes region. Back then, the entire area was covered with a sheet of ice that averaged a half-mile thick, but was up to four times that in some places.

As temperatures warmed, the melting glacier moved slowly toward Canada, its massiveness gouging the land beneath it, leaving behind a handful of deep depressions.

Meltwater filled those newly created basins and…voila! The Great Lakes were born—although they didn’t take their final form for a few thousand more years.

So thanks to a glacier, we have five fantastic freshwater lakes and the familiar Michigan “mitt,” a hand-y landmark that is easily recognizable from space.

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Permanent link to this article: http://www.currentcast.org/water-and-climate-change/of-ice-and-mittens-or-how-the-great-lakes-formed/