2g. Glaciation

For coal miners, glaciation can present challenges because the coal may not be easily accessible in areas where glaciers shaped the landscape. Glaciers are large bodies of ice that move over Earth’s surface. A glacier is formed as snow accumulates over time and turns to ice. This process can take more than 100 years. Once a glacier has formed, it moves very slowly, and can take years or even decades to move. North Dakota was covered by glaciers at three different times, with the most recent glaciation episode from 18,000 to 25,000 years ago.

These images show different features of North Dakota’s geography, including glaciated plains. The glaciated plains of the eastern side of the state are marked by flat topography, rich soil, and deposits of sand and gravel.