Essential Science Ground Water and Glaciation

Britannica tells us the Pleistocene epoch, the great ice age, began about 2.5 million years ago and ended about 11,000 years ago. There were four glacial advances during the Pleistocene, illustrated in the chart below. The last great glacial advance of the Pleistocene began about 75,000 years ago and ended (way up in the True North) about 9,000 years ago. That last glacial advance, the one that built the moraine where my family lived, we call the Wisconsin Glacial Stage or the Wisconsin Glaciation. That’s the one that shows the green moraine areas on last week’s map. It’s the one that is most recognizable on the landscape today. Go to southern Illinois or southern Iowa to see the remains of the Illinoian glaciation. Trust me, the Wisconsin deposits are way more interesting.