Bayan wani lokaci na volcanism 1.1 biliyan shekaru 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 da Canadian Shield a arewa maso gabashin Minnesota.
arewa maso gabashin Minnesota