Nature Notes: Discovering traces of Iowa’s glaciers

Most people would expect to trek to Alaska or the northern Rockies to experience glaciation. However, they can stay close to home and enjoy glacial handiwork right here in Iowa.

This is a story of one glacial boulder. Hundreds of thousands of years ago a massive glacier covered North America like a giant pancake. It picked up a huge rock in Canada or Minnesota and slowly carried it on a long journey south. As the glacier moved the rock rubbed against others and was gradually smoothed. Eventually the climate warmed, ice melted, and the giant rock dropped out of the ice and came to rest where the town of Marion was founded thousands of years later.

Iowa didn't experience just one glacier. It had many, often separated by hundreds of thousands of years of ice free climate. Occasionally a new glacier would pick up rocks left by previous ones and continue moving them. Because these rocks are geologically out of place they are called glacial erratics. If only they could talk! What a story of their immense journey they would reveal.

Glacial erratics are common. Perhaps the best known one is a big one in Cedar Rapids' Bever Park loved and clambered on by countless children over the decades. Smaller ones have been unearthed and are used in landscaping. Thanks to the generosity of Waldo Morris the huge rock in Marion will be the centerpiece of a new city park that will open in 2017.

Waldo's Rock Park will be about seven acres, including a pond and picnic shelter, but it's main attraction will be the largest known glacial erratic in Eastern Iowa. Vehicle access will be from Partner's Avenue off Highway 13 just south of the US 151 Intersection. Although the park won't open until next year the rock is clearly visible from the nearby Grant Wood Trail and is only a few hundred yards east of the trail head. What a delightful wonder and generous gift by Waldo Morris.

Marion Patterson is an instructor at Kirkwood. Rich Patterson is the former executive director of Indian Creek Nature Center in Cedar Rapids.