Friday, January 26, 2007

Global Warming, Lake Minnetonka and Kettle Lakes

A Lake Minnetonka Geograpahic essay - from the Minnesota Department of Transportation.

This is copy taken from a plaque, at the edge of Lake Minnetonka, in Excelsior.

This plaque was erected by the Geographical Society Of Minnesota, with the partnership of the Minnesota Department of Transportation.

“At the peak of the last glacial period, or Wisconsin glaciation (you know those “cheddar heads” were involved - my comment) an advancing glacier passing over the ancient river valley that now lies beneath Lake Minnetonka, filled the valley with ice. Sediment that melted out of the overriding glacier buried the ice trapped in the valley. The glacial ice and sediment were then covered by additional sediment from more recent glacial advances. As a result when glaciers last receded form Minnesota 10,000 years ago, large blocks of ice were buried deep in the ancient valley under thick piles of sediment. When the ice blocks melted, the overlying sediment collapsed and created numerous depressions that filled with water, which are called kettle lakes. At Lake Minnetonka, the ice blocks were so big and close together that the depressions coalesced to form the large composite kettle lake that we see today.”

The Minnesota Department of Transportation and Minnesota Geograpahical Society.

I urged “Urg” to get a smaller cave, not to buy that SUV 10,000 years ago, but he wanted to drive to Maynards for a Walleye Sandwich.


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