End Moraines

This photo shows a moraine forming at the margin of a glacier in eastern Canada. Photo by W.W. Shilts.

We tend to think of Illinois as very flat, but bike riders and joggers know that our landscape has many subtle hills, ridges, and long uphill slopes. From a satellite or the space shuttle high above the earth, large broad ridges can be seen that arc across northeastern Illinois. These ridges, left behind when the last Ice Age glaciers melted away, are called end moraines; they formed between about 25,000 and 14,000 years ago during the Wisconsin glacial episode. Although these ridges are easy to see from space, they are so broad and rounded you may sometimes overlook them when you drive across Illinois. This urbanized area near the center of this satellite photo is Champaign-Urbana. The end moraines show up in a lighter color.