Final answer:
The Great Lakes were formed by continental glaciers rather than alpine glaciers. Continental glaciers, with their massive size, reshape large landscapes, creating features like glacially-formed basins that we see as the Great Lakes.
Step-by-step explanation:
The Great Lakes were formed by the action of continental glaciers during the last Ice Age. These glaciers were vast ice sheets that covered significant portions of the northern continents, sometimes reaching as far south as 40° latitude. However, alpine glaciers, which are typically found on mountainsides, such as the current shrinking glaciers seen in Glacier National Park (GNP), are much smaller in scale and behave differently. Continental glaciers, due to their immense size and weight, have profoundly reshaped the landscapes they covered, including the depression of the Earth's crust beneath them, flattening and scouring the land, and creating unique geological features such as the Great Lakes, which are glacially formed basins filled with water.
Comparatively, alpine glaciation is characterized by its ability to carve out steep, U-shaped valleys, sharp ridges, and pinnacles in mountainous regions. Glacial lakes can come in various forms, such as tarns, which are found in steep-walled basins created by glaciation in mountains, or larger lakes created in depressions left behind by continental glaciers.