Wild Things: Kettles, Moraines and Kames in DuPage County
You may consider the landscape of DuPage County and northern Illinois relatively flat and featureless. But if you know what to look for and look closely, you’ll discover otherwise.
There’s plenty of evidence of glacial movement in the DuPage forest preserves in the form of kettles, moraines and kames, according to District naturalist Abby Dean.
Much of the area’s topography was formed by the Wisconsin glaciers that moved through the area 13,000 to 25,000 years ago. Moving like slow, giant bulldozers over the land, glaciers created land features in a cycle of advancements and retreats over a period of thousands of years, said Dean, estimating their movement at 1/3 of a mile per year.
Gently rolling ridges of soil and till called moraines were formed when forward-moving glacier stopped, depositing the materials. Several glacial moraines wrap around Lake Michigan, including the Tinley moraine, which ends as the Salt Creek overlook at Fullersburg Woods Forest Preserve in Oak Brook.
“People often think these ledges are the result of river valleys, but the rivers actually formed in the valleys between these moraines,” Dean said.
Waterfall Glen in Darien has an area on the west side called Kettle Woods where visitors can find kettles, which are depressions or potholes. Kettles are formed when a chunk of ice breaks away from a glacier and is buried. Then when the ice melted, it formed a water-filled depression.
A kame, or low, steep irregularly shaped hill of sand and gravel, can be seen just inside the entrance to Blackwell Forest Preserve in Warrenville. The kame can be seen from the first parking lot inside the entrance to Blackwell off Butterfield Road.
Songbird Slough in Itasca also has a couple kettles, as does Maple Grove Forest Preserve in Downers Grove, although it's no longer filled with water, Dean said.
Dean talks more about moraines, kettles and kames on Wild Things on WDCB Radio (90.9 FM).
Kettle Woods at Waterfall Glen in Darien.
The Tinley moraine overlooking Salt Creek at Fullersburg Woods.