TRAVELING THE ICE AGE NATIONAL SCENIC TRAIL
Badger Science Writers, is an informal group who gather for mutual support and some very interesting field trips. A few weeks ago, we hiked a stretch of the Ice Age National Scenic Trail near Cross Plains, WI, to learn about ice age geology still evident in the terminal-moraine landscape where the trail traces a line that demarcates the furthest advance of the last great ice sheet in Wisconsin.
The Ice Age Trail is a Wisconsin gem. One of only 11national scenic trails, it is located completely within our state, where its thousand-mile foot path follows some of the most dramatic glaciation-sculpted planetary features in existence.
To the trained eye, the glaciated landscape stands out almost as clearly as it did when the ice sheet ground to a halt in that very spot over 12,000 years ago. And we had an exceptionally well-trained pair of eyes along with us sharing his insights: UW-Madison Professor emeritus David Mickelson, who for years has made the Ice Age Trail one of his areas of focus.
You can find many great hikes along this trail with an interactive map which provides notes on current trail conditions of the section you are heading for. For an even more in-depth guide, there’s the newly-published book Ice Age Trial Guidebook 2014 available from the Ice Age Trail Alliance bookstore.
Glaciers a mile or more thick have advanced and retreated some 15 times in the past 2.5 million years across our region and have scraped out and then built up the contours of about a third of the earth’s landmass. The last three glaciers in the Midwestern US either stopped or skirted, and then retreated without bulldozing over a pocket of land in the southwest corner of Wisconsin and adjoining bits of Iowa and Illinois, defining the outlines of the area now known as the Driftless Area. To the north, south, east and west of the Driftless Area, a much younger landscape exists, shaped by one or more of these last three glaciers. But in my neck of the woods, the Driftless Area has topography that is perhaps fifty times older than the glaciated landscape beyond. (When glaciers recede, the debris they leave behind, transported in some cases from hundreds of miles away, as they melt is called drift. )
Volunteers Retracing and Blazing the Ice Age Trail
The Ice Age National Scenic Trail is being carved out slowly (in human, not glacial perspective) by the efforts of a mostly volunteer force who are surmounting the lack of government funding with their own energy and determination. I think this example of citizens working to make something wonderful happen is as fantastic as the trail itself. Each year hundreds of volunteers give thousands of hours to extend the segments of trail and care for existing sections. It’s a mammoth task!
Gary Werner, Executive Director of the Partnership for the National Trail System and volunteer coordinator for our area, was also on the hike, and he pointed out what volunteers have and have not been able to do as they fight back encroaching invasive plants that blanket and often mask the contours carved by the ice.
As Dr. Mickelson explains in the book he co-authored, Geology of the Ice Age National Scenic Trail, moraines are ridges of glacial debris. End moraines are made of the debris that had been carried on the glacier’s leading edge and then left behind as the ice melted away and receded.
On the Edge
It was a perfect spring afternoon as the Badger Science Writers stood on the Johnstown Morraine, a mound of glacial deposit about 50 feet thick, and looked west into the Driftless Area – right on the brink between two dramatically different parts of Wisconsin.
In the Driftless, the terrain has been carved into ridges and deep, winding valleys by more than 250,000 years of weathering and water coursing. Behind us was a much newer landscape. 12,000 years ago we would have been standing on the leading edge of an ice sheet that stretched all the way to the Atlantic Ocean. Dr. Mickelson estimates that the ice pack over what is now the state capitol building in Madison was probably about 800 feet thick. It was probably more than half a mile thick over what are now the cities of Green Bay and Superior.
As all that ice melted, it left a thick layer of drift dotted with depressions that give the glaciated part of the state all it’s lovely lakes.
Watch Out – Cold Water Coming Through
Mickelson described how as the meltwater had coursed past where we stood along the edge of the warming glacier, and at some point it found a weak spot where it could bore through. He said it was like pulling the plug in a bath tub, and water rushed through, ripping a deep gorge through both soil and bedrock. He said the whole explosive event may have taken only a few day’s time.
We followed the trail a little farther to the edge of the gorge formed by the rushing water and peered down at tree tops below us. It’s a peaceful spot today, but on another day some 10,000 years ago, it was a different story as the violent pressure of icy water hammered its way toward lower land beyond, which remains marshy to this day.
We followed a circuitous route back to the road, and its bridge over the gorge, then we hiked to the opposite side of the gorge.
Schuler talked about how the National Parks Service considered spanning the gorge with a bridge so that hikers could walk straight across it and appreciate it from above, but a construction like that would really compromise the current natural feeling of the area. Also there is no money for a project like that at this time.
Part of the volunteers’ efforts are to extend the trail and clear the surrounding area of invasives, which are so thick in places that you can’t even see the broad strokes carved into the landscape by glaciation. It’s a constant battle. Along the part of the trail we were walking, volunteers have been returning the area to its pre-settlement condition, which was prairie. That gives a little better view of the lay of the land. Perched on the northern edge of the great tall grass prairie that covered much of our part of the country, a restored prairie should make a great and long-lasting addition to the trail’s landscape in a warming world.
The goal is to join all the existing segments of the trail, but that will be a task of many years to gain funds and permissions to access or obtain private lands along the way.
After a few hours of hiking through terrain that is today a peaceful echo of the monumental forces that shaped it, the Badger Science Writers repaired to the Crossroads Coffee House next door to the Ice Age Trail Alliance headquarters in Cross Plains where we could further ply our presenters with more questions and wet our whistles. Doug and I enjoyed a local IPA called Glacial Trail, from Central Waters brewed in honor of this unique landform, to celebrate this amazing enterprise.
A few days later, we returned to the Ice Age Trail Alliance to pick up a few books, and decided to become members. It’s just too cool a project not to get involved.
If you live near any part of this amazing trail – check it out. And if you are looking for a volunteer activity that will get you out into nature and make you a part of something bigger than yourself, consider helping to build the Ice Age National Scenic Trail. Learn how to volunteer here.
Jo Ellarson, who works for the Ice Age Trail Alliance tells me that the volunteers work hard and play hard and have a really great time.
Have you been on The Ice Age National Scenic Trail? What part?
Categories: Eco activism
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