Bayan wani lokaci na volcanism 1.1 biliyan da suka wuce, Minnesota ta geological aiki ya kasance mafi subdued, ba tare da volcanism ko dutsen samuwar, amma tare da maimaita rashin teku, wanda ya bar baya mahara yadudduka na sedimentary. A cikin 'yan kwanan nan, m kankara sheets ravaged jihar ta basaltic wuri mai faɗi da kuma sculpted ta terrain. A game da 2.7 biliyan shekaru da suka wuce, ragowar wannan volcanic dutse kafa Canadian Shield a arewa maso gabashin Minnesota. Tushen wadannan volcanic duwãtsu da kuma mataki na Precambrian teku kafa Iron Range na arewacin Minnesota.
Shekaru 12,000 da suka wuce