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Earth Cache
1. To learn something about our planet.
2. The lesson that you learn is learned forever.
3. Leave nothing but your footprints behind, and always practive CITO.
The icy grip of continental glaciers was one of the most significat geologic processes to affect the Iowa landscape. Most of the deposits underlying today's land surface are composed of materials known as drift that were moved here by glaciers. The arrival of these glaciers in the state began over two million years ago, and numerous reappearances are recorded in the deposits they left behind. For all of this massive effort, however, only the landscapes of north central Iowa still display the actual shapes that resulted directly from glacial action. This region, known as the Des Moines Lobe, is the part of the state that was last touched by the huge sheets of frozen water that invaded Iowa in the past. This last glacial episode occured only 12,000 to 14,000 years ago.
The Des Moines lobe covers a large part of Iowa having advanced through North and South Dakota and Minnesota and into north central Iowa, halting at what is now the city of Des Moines. This episode of glacial activity, composed of at least three major surges, was followed by large-scale stagnation of the glacial ice. The process of decay and disintegration was the dominate method of ice "retreat" over large areas of the Des Moines Lobe. The limits of the three major glacial advances are marked by the Bemis, Altamont, and the Algona end moraines as shown in the figure below.
Landforms and deposits vary along these former ice margins. The portion of morainal ridges extending east west across the interior portion of the Lobe appear as smooth, prominent, south-facing escarpments, as much as 120 feet high. They formed along the central axis of the surging glacier, where the ice was especially mobile. This region of active oscillations of the ice front had a relatively uncomplicated history of melting. The process left behind thick deposits of compact, uniform pebbly loam called glacial till and generally produced low-relief landscapes punctuated by distinct ridges marking the limits of major ice advances. These ridge fronts are easily visible and are very visible at the site of this earthcache.
It is just a short hike from the parking area to where the posted coordinates take you. At that spot you are standing on the conspicuous edge of the Algona end moraine. This was the "end of the road" for the glacier that was here 12,500 years ago. As it melted, the gravel and rock that it had carried with it dropped out and remains as a high ridge today. This ridge marks the last advance of the Des Moines Lobe ice sheet.
To log this earthcache you will need to perform these taskes.
1) At the coordinates what is your elevation.
2) Look to the North, are you at the highest point of this ridge?
3) Look to the South, estimate how much higher you are than the closest farm.
4) While still facing South describe the view and the topography in front of you.
Send your answers to me through the cache page.
Not required, but always nice, please post a picture of yourself or your team with your gpsr at the location in your online log. Please, No spoiler pictures of the view to the South.
Development of this Earthcache was approved by the Kossuth County Conservation Board.
Stinson Prairie where this earthcache is located is managed by the Kossuth County Conservation Board and public hunting is allowed. Please be aware of your surroundings during hunting season.