Glacial deposition occurs when glaciers melt and release the materials they have carried, such as rocks, soil, and sediment. As glaciers move, they erode the landscape, picking up debris along the way. When they retreat, this debris is left behind, forming various landforms like moraines, drumlins, and outwash plains. The materials deposited by glaciers can vary in size, from large boulders to fine silt. This process plays a significant role in shaping the Earth's surface and contributes to the formation of features found in areas previously covered by glaciers, such as the Great Lakes and the Scandinavian Peninsula.