Geology of Minnesota - Minnesota Today

Minnesota Today

Contemporary Minnesota is much quieter geologically than in the past. Outcroppings of lava flows and magma intrusions are the only remaining traces of the volcanism that ended over 1,100 mya. Landlocked within the continent, the state is a long distance from the seas that once covered it, and the continental glacier has receded entirely from North America. Minnesota's landscape is a relatively flat peneplain; its highest and lowest points are separated by only 518 metres (1,699 ft) of elevation.

While the state no longer has true mountain ranges or oceans, there is a fair amount of regional diversity in landforms and geological history, which in turn has affected Minnesota's settlement patterns, human history, and economic development. These diverse geological regions can be classified several ways. The classification used below principally derives from Sansome's Minnesota Underfoot - A Field Guide to Minnesota's Geology, but is also influenced by Minnesota's Geology by Ojakangas and Matsch. These authorities generally agree on areal borders, but the regions as defined by Ojakangas and Matsch are more geographical in their approximations of areas of similar geology, while Sansome's divisions are more irregular in shape in order to include within a region all areas of similar geology, with particular emphasis on the effects of recent glaciation. As glaciation and its residue has largely dictated regional surface geology and topography, Sansome's divisions are often coextensive with ecological provinces, sections, and subsections.