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A Journey to a New Land

Sea Mammals
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Dr. Michael Wilson

Geology Department, Douglas College

Ice Free Corridor

The Ice Free Corridor is kind of an intriguing name. I guess a lot of people who think about the ice free corridor when they first hear about the concept, they imagine this narrow passageway with towering walls of ice on either side of it to the east and the west, but I’ll have to put that name in some context.

First of all, we are talking about an area of western Canada that extends from the southern Yukon down through Alberta and actually into Montana because the southern end of the ice free corridor was actually to the south of the Canada-US border at the maximum extent of the ice. And we are talking here about ice sheets that expanded from two directions and came together, basically coalesced, in the last glacial maximum around 15,000 years ago. Ice expanded from a center in the east, which we refer to as the Laurentide Ice Sheet. The major area of expansion was from the Hudson’s Bay area outward to the west and the south. And ice also expanded from the mountains to the west, expanded outward east, west and south from ice sheets that were developing in the mountain area. So on the plains of Alberta, in particular, these two ice sheets coalesced, or came together, in the last glacial maximum, and as you might imagine when the glaciers started to retreat, melting back, that was the first area to open up. So that area of opening has been referred to as the Ice Free Corridor.

The timing of that opening is obviously a very important question. In fact, archaeologists and paleoecologists for years debated the issue as to whether the corridor ever completely closed during the last glaciation. So issues like this become very important in terms of the first peopling of the new world.

The ice free corridor as a feature on the landscape was of very fleeting duration. As you can imagine, if we are talking about ice retreat actually there was no sustained period where you had a narrow passageway and towering walls of ice. Actually very quickly this became a widely open area with ice well off to the east and ice well off to the west. Basically what we usually refer to as the ice free corridor would have been a broad, open steppe tundra in between two distantly separated ice sheets.

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