Ten thousand years ago, at the end of the last ice age, Vilas County was locked under a solid layer of ice. The glaciers are long gone now, but you can still see evidence of them everywhere you look. I wrote over the summer about how the retreating glaciers formed the kettles that are now our many lakes and bogs – this county has the highest density of natural freshwater lakes of anywhere in the world. The lakes may be the most obvious signature the glaciers left behind, but they’re not the only one.
The photo above was taken standing on top of an esker – you can see that you’re looking along a ridge that drops off on either side.
Eskers are formed by streams of liquid water flowing under and through glaciers. As it flowed, the stream deposited a ribbon of gravel and sediment between the ice walls surrounding it. When the glacier retreated, this is what was left behind. Ours snakes along the margin of one of our kettle bogs.
We also have a lot of till, jumbled collections of rocks and boulders that the glaciers scraped up somewhere else and dumped here. The rocks I flipped for International Rock Flipping Day this year arrived on the property this way.
Was the area where you live ever glaciated? How can you tell?
Further reading: Pleistocene Geology of Vilas County, Wisconsin