|Here a river has cut through a glacial feature known as a moraine. It's in a forest preserve in Palos Hills, IL, which is is just outside of Chicago. That's me. Picture by my friend Tom.|
Have you ever seen a pile of fine dirt mixed with random rocks? Have you ever wondered what that was?
If you live anywhere near the Great Lakes, you're very likely looking at a natural sediment called till. Till is one of the signs that glaciers once covered the area around the Great Lakes.
Other features that are easy to spot are large, rounded rocks that look like they were just dropped there. Those are erratics*. They're very often made of granite. This is because granite is so hard it's difficult to erode.
|An erratic from the same area of Palos Hills. Photo by me.|
You can also find long, deep scratches or grooves across rocks. These are known glacial striations.
|Glacial striations in a small trough. This photo was taken near the entrance of Keewaydin State Park in Alexandria Bay, NY. Those are my keys for scale. Photo by me.|
So if you live anywhere near Chicago or in the state of New York, evidence of glaciers are all around you. So keep your eyes open for them!
*This blog is named after glacial erratics.