GEOMORPHOLOGIC FEATURES

A generally low relief surface characterizes the topography through which Minnesota’s streams and rivers flow, as shown in Figure 2.2. The areas of greatest relief are located along the north shore of Lake Superior and in southeastern and southwestern Minnesota where streams descend into the Mississippi and Minnesota rivers, respectively. The state’s topographical features, created largely during the most recent glacial periods, reflect a long period of geologic stability.

Figure 2.2 Topographic Regions of Minnesota. Adapted from MEQB-Lakes (1994). Minnesota Lake and Watershed Data Collection Manual, p. 69.

Minnesota’s soils developed within the last 15,000 years from glacial sediments. A blanket of glacial sediments and meltwater deposits covers the state’s older bedrock. The depth of glacial sediments is thickest (up to 150 meters) in northwestern Minnesota and thinnest in the Arrowhead and the southeastern Mississippi River valley regions. The variation in soil types across the state reflects differences in local erosion patterns and deposition of sediments during and after recent glacial periods. In general, however, soils tend to be rich in minerals because they are relatively new.