Glacial history of the Mackenzie region

The present landscape of the Mackenzie valley is primarily a result of the last continental glaciation which covered most of the area about thirty thousand years ago (30 ka BP). This glaciation resulted in rearrangement of the preglacial drainage system, including redirection of much of the Mackenzie River drainage to the Arctic Ocean. Meltwater channels established along the edge of the retreating ice sheet became parts of present Mackenzie River tributaries. Lakes were impounded by the ice as it retreated rapidly into the present Mackenzie valley area about 13 ka BP. These glacial lakes received silt and clay accumulating to thicknesses of several tens of metres. Today these sediments include some of the more problematic ice-rich materials with which engineers and construction personnel must deal. By 10 ka BP, the Mackenzie valley was ice-free. Northward tilting of the land continuing to empty and shrink the remaining glacial lakes to their present size.