Indian Mounds Park

GEOLOGY OF MINNESOTA AT THE MOUNDS (AS DESCRIBED IN A PLAQUE ON THE BLUFFS ABOVE THE MISSISSIPPI) indian_mounds_plaque THIS POINT COMMANDS A VIEW OF ONE OF THE GREAT WATER COURSES OF NORTH AMERICA.  THE STREAM WHICH ONCE FILLED THIS VALLEY NAMED THE RIVER WARREN WAS LARGER THAN ANY RIVER ON THE CONTINENT TODAY. DURING THE PAST MILLION YEARS MINNESOTA HAS BEEN PARTLY COVERED BY GLACIERS AT LEAST 4 TIMES. THE SHORT SUMMERS AND LONG WINTERS OF THE GREAT AGES CAUSED AN ACCUMULATION OF SNOW AND ICE TO A THICKNESS OF SEVERAL THOUSAND FEET. AS THE CLIMATE MODERATED AND GLACIATION CAME TO AN END ENORMOUS QUANTITIES OF WATER WERE RELEASED TO FLOW IN RIVERS AWAY FROM THE ICE FIELD.  THE VALLEY OF THE MISSISSIPPI FROM THIS POINT WAS ERODED BY SUCH A STREAM ABOUT 2000 YEARS AGO SCOURED TO A DEPTH OF 100 FEET BELOW THE PRESENT RIVER SURFACE. THE VALLEY WAS LATER FILLED BY SAND AND GRAVEL AS THE FORCE OF THE TORRENT SUBSIDED.

 

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