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A Journey to a New Land

Yukon Horse
Post secondary Level Resources

Geology in the Ice-free Corridor

Geologic research has supplied valuable evidence concerning the existence and extent of the ice-free corridor. Geologists have studied landforms and deposits such as moraines and glacial tills to determine the extent and duration of ice cover during the Late Wisconsinan Glaciation, as well as the location, size and duration of the large glacial lakes that characterized the corridor environment as the ice age began to wane.

As the Laurentide and Cordilleran ice sheets began to melt and recede, an area of unglaciated land between the ice sheets - an "ice-free corridor" - did open up and was eventually occupied by groups of early humans. However, it now appears likely that the corridor did not exist throughout the Late Wisconsinan Glaciation. A comprehensive study of the Foothills Erratics Train in southern Alberta has provided compelling evidence that the Laurentide and Cordilleran ice sheets met and coalesced by about 21,000 years BP, and that no unglaciated corridor between them developed until perhaps as late as 12,000 years BP. It may have been considerably later before the corridor was habitable for humans or the grazing animals they hunted.

Studies of glacial deposits suggest that a large part of the two ice sheets were coalesced above central Alberta, near Edmonton, until long after the glacial maximum. Geologists use the rubble caught up by glaciers and deposited and the borders of the ice sheet to demonstrate the furthest extent of the sheets. Using this evidence, called ‘moraines’ and ‘tills’, most researchers agree that passable areas between these two glacial sheets would have been virtually non-existent until at least 14,000 years ago.

However, there is some scant geological evidence suggesting that there may have been open areas occasionally appearing between the two ice-sheets. Andrew Stalker, a geologist with the Geological survey of Canada, suggests that small areas of unglaciated areas were opening and closing in the corridor between 19,000 and 14,000 BP. This theory is yet to be substantiated by further research and remains controversial.

If humans passed through this corridor while the glaciers remained near their maximum extend, what would have this land looked like to them? Doubtless these early travelers where well versed in dealing with dangerous terrain, but what would they have to deal with when traveling between two giant sheets of ice?

Foothills Erratic
This example of a Foothills Erratic is located near Glenwoodville, Alberta.

© Lionel Jackson
Used with Permission

Lionel Jackson's Foothills Erratics Train website

Archaeology in the Ice-Free Corridor
Geology in the Ice-Free Corridor
Environment of the Ice-Free Corridor
A South to North Migration?