The Ice That Made All This

Everything you will look at today was made by ice, and recently enough that the land is still adjusting.

Twenty thousand years ago you would be standing under a glacier a mile thick. The Great Lakes basins are the grooves those ice lobes gouged out as they ground south. The hills around you are moraines — the piles of clay, gravel and boulders the ice shoved ahead of itself and abandoned when it stopped.

Then, around eleven or twelve thousand years back, it let go. Meltwater filled the basins, and the land itself — relieved of all that weight — began slowly springing back upward, which it is still doing today at a few inches a century.

Three things you can read from the car. The long parallel ridges of this peninsula are moraines. The inland lakes are drowned valleys, or hollows left where buried blocks of ice melted out. And the odd flat terraces partway up some hillsides are old beaches, from when the lake stood far higher than it does now.

That last one is worth dwelling on. There are ancient shorelines up in these woods, hundreds of feet above the current water, with wave-rounded pebbles still lying on them. This lake has been many different lakes.

So the scenery is not ancient the way mountains are ancient. Geologically speaking this landscape is about a week old, and it has not finished settling.