Travelers along Interstate 90 through south-central Minnesota can attest to the admittedly un-exciting drive. Basically flat and non-descript, the landscape here might be described by some as snooze-worthy. This area of mostly level, gently rolling terrain is underlain by thick glacial drift, which is unsorted rock debris left behind by a melting glacier. Such a landscape of glacial drift, or till, is called a till plain. They are created by rapid glacial melting over a large area. This particular till plain, known as the Blue Earth till plain, extends south from the Minnesota River down to the Iowa border and from the base of the Coteau des Prairies near Fulda and Walnut Grove in the west to the hills of the Owatonna moraine complex along the I-35 corridor in the east. The name "Blue Earth" originates from the Dakota Indian term "Mahkota" (meaning 'blue earth') for the color of the blue-black clay found in the banks of the river flowing through the area.
This region was under the Des Moines lobe, the last glacier to cover south-central and southwestern Minnesota. This large river of ice was fed by the Laurentide Ice Sheet in Canada and flowed south and east until reaching near what is now Des Moines Iowa around 14,000 years ago.
As the climate gradually warmed the glacier started to thaw, taking approximately two thousand years to melt back out of Iowa and southern Minnesota. As it melted the glacier left behind at least 100 feet of limy, gray, shale-filled drift that covered the original bedrock, old drift, and pre-existing topography. The resulting terrain is generally even and regular, with gently rolling hills and an occasional shallow lake.
When the glacier had retreated the region was quickly covered by spruce forest. Later, as the climate warmed and dried, prairie grasses became the dominant plant form. The growth and decay of the lush prairie grasses have over the past 9000 years or so altered the basic structure, texture, chemistry and organic content of the fresh glacial drift. Fertile soils one foot or more in thickness have developed over the entire region. This is the soil that has made this one of the most valuable agricultural areas in the world.
The posted coordinates will bring you to an off-ramp of I-90. There you can park and take in the 360° view of patchwork-like fields of different crops stretching off to the horizon.
To log this earthcache please do the following:
1. Send the cache owner listed near the top of this page an email; click on their name, then the "send message" link. Using your GPSr, what is your observed elevation at the posted coordinates (do not post in your log).
2. If you would like to include a picture of you or your group at the location that would be appreciated, although as per EarthCache guidelines it is not a requirement.
3. Just for fun, in your e-mail describe what crop is currently growing in the farm field northwest of your location (in the winter months there may still be evidence of the past summers crop, tell me what you think it might have been).
