Ihe dị ka ijeri afọ 2.7 gara aga, lava basaltic wụsara site na cracks na ala nke oké osimiri oge ochie; ihe fọdụrụ nke nkume mgbawa a kpụrụ Canadian Shield na n'ebe ugwu ọwụwa anyanwụ Minnesota. Mgbọrọgwụ nke ugwu mgbawa ndị a na ihe omume nke oké osimiri Precambrian kpụrụ Iron Range nke ebe ugwu Minnesota. Mgbe oge nke mgbawa ugwu 1.1 ijeri afọ gara aga, ọrụ geological nke Minnesota adịla ala, na-enweghị mgbawa ugwu ma ọ bụ ugwu ugwu, ma na-anọghị n'oké osimiri ugboro ugboro, nke hapụrụ ọtụtụ ọkwa nke sedimentary. N'oge na-adịbeghị anya, ice sheets dịkarịa ala otu kilomita na-emebi ala ọdịda anyanwụ nke ala ma na-eme ka ala ya dị elu.
ebe ugwu ọwụwa anyanwụ Minnesota