I have a question with possible geological implications…

Stretching North and West of the Great Lakes is a great arc of enormous lakes reaching across Western Canada almost to the Arctic Ocean.

These include, starting from Lake Superior, Lakes Winnipeg, Athabasca, Great Slave and Great Bear. Their large size, linear arrangement and regular spacing suggests that this is not a chance arrangement. Are you aware of any tectonic or structural formations or events that might possibly have created this feature? Or is this geometrical spacing simply a coincidental result of random local topography and drainage?

My teachers suggested it might be the trace of some ancient glaciation, that these might be glacial lakes or the result of terminal moraines, but I thought the continental glaciers made it much further south than this.