Midcontinent Rift System Map

The Midcontinent rift system cuts across terranes ranging in age from 3.6 to 1.65 Ga. The location of the rift south of Lake Superior in Minnesota, Michigan, Wisconsin, Iowa, Nebraska, and Kansas is inferred from gravity and magnetic data. The hachured areas denote volcanic basins and the stippled areas represent sedimentary basins (Figure 1 from Nicholson et al., 1992).