Track 2—Geology

The land that we know as Iowa has seen a lot geologically. The most recent event gifted Iowa with some of the richest soils in the world.  Twenty thousand years ago, Iowa was situated along the southern edge of the Laurentide Ice Sheet. An ice sheet is a conglomeration of glaciers, each one a frozen river plowing its way along the earth’s surface.

     The Laurentide Ice Sheet was over 2 miles thick in places and gouged out the Great Lakes, completely flattened mountain ranges, and lowered the sea level by over 400 feet. As the ice sheet pushed southward it carried on it soil from the north and deposited it in Iowa. The nutrient rich topsoil became the foundation for North America’s vast grasslands and ultimately would make Iowa an agriculture giant.

    Deep below Iowa's topsoil is another story, the stacked rock layers tell the story of a cycle of inland seas, and pressed between them is a coal seam dating back to the Pennsylvanian Era, almost 300 million years ago. At that time Iowa was a swampland near the Equator. On what is now the refuge, 10 coal mines once operated. Southwest Iowa coal mines were a driving force in the industrialization of Iowa at the turn of the 20th Century.