Geology of the Lake Mille Lacs Region
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MNSearchers
N 46° 09.849 W 093° 28.268
15T E 463627 N 5112393
This areas geological history is a story of immense natural forces at work over thousands of years. The rolling hills are actually a part of a terminal moraine.
Waymark Code: WM2DKV
Location: Minnesota, United States
Date Posted: 10/16/2007
Views: 85
Almost all the Lakes in Minnesota were formed by glacial action. Many small lakes formed after the glaciers receded and blocks of ice buried in the sediment melted, leaving holes, called kettles, that filled with water. Other lakes occupy basins that were scraped out of solid rock by glacial ice. Lake Superior is a prominent example of a lake bottom scoured by glacial ice. Lake Mille Lacs, by contrast, is not really in a basin. It is surrounded on the north, west, and south sides by a moraine - a ridge of sediment left along the edge of a glacier. With the land on the eastern shore also being of higher elevation, the moraine effectively dams the drinage to the south to form one of the largest lakes in the state.
This areas geological history is a story of immense natural forces at work over thousands of years. The rolling hills are actually a part of a terminal moraine. The small, but abrupt hills, were formed approximately 15,000 years ago when a major glacier stopped its advance south. As the glacier melted, it deposited gravel, rocks, and boulders that it had accumulated in its grinding passage over to the north and east. The resulting land form is referred to a terminal moraine. The glacial debris partially blocked the land's natural drainage patten and in effect became a huge dam, creating an extensive lake of melt water - a lake even larger than the present day Mille Lacs. This ancient lake had three outlets and a shoreline 15 feet higher than the present lake. A long period of geological and vegetational succession followed. The outlet streams cut deep channels. Ponds and small lakes drained away. Wave and ice action built up beach ridges. Drainage patterns and the shape of lakes altered. Silt and vegetation filled many of the depressions. The present park of Kathio - its soil, vegetation, and wildlife - is the result of these thousands of years of constant natural progression.
Marker Type:: Roadside
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Visit Instructions:
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