|Not through here|
The argument is based on extensive evidence showing that such a corridor between the major ice sheets would not have been open and habitable by plants, animals, and humans at the time when it is known that humans were already present in the Americas south of the ice. Any passage between through the ice sheets simply opened up too late to be the vital route of migration.
It's impressive news, but it also suggests science works slowly. I made a radio documentary for Ideas 25 years ago called "Peopling the Americas," and even then the fieldwork researchers were pretty conclusive. Analysts like Carol Mandaryk, then of University of Alberta, and Glen MacDonald, then at MacMaster, told me flatly that pollen evidence showed virtually no organic matter being deposited in the corridor early enough for it to be a place of human habitation or even travel.
There isn't enough here to support any animals, and if there aren't any animals and there aren't any fish in the lakes, what are the people living on? You don't have a viable environment.That is what the Nature article confirms in even more detail (my informant Mandaryk is among those cited in the notes).Twenty-five years ago, theorists like Jon Driver of Simon Fraser were already describing the "ice-free corridor" explanation as "more widely held perhaps ten years ago than it is today."
One consequence of the latest disproof of an inland migration route: fresh honour for Simon Fraser archaeologist Knut Fladmark, who argued as early as 1979 that the ice-free corridor was not viable, and that by far the most plausible alternative route for humans to enter the Americas south of the glaciers was down the Pacific Coast -- a theory that has become steadily more credible and supported by evidence ever since.
The PCM [Pacific Coast Migration] model was first considered in detail by Knut Fladmark, in a 1979 article in American Antiquity which was simply amazing for its time. Fladmark argued against the Ice Free Corridor hypothesis, which proposes people entered North America through a narrow opening between two glacial ice sheets. The Ice Free Corridor was likely to have been blocked, argued Fladmark, and if the corridor was open at all, it would have been unpleasant to live and travel in.
Fladmark proposed instead that a more suitable environment for human occupation and travel would have been possible along the Pacific coast, beginning along the edge of Beringia, and reaching the unglaciated shores of Oregon and California.The other thing confirmed: Canadian First Nations are right to say they have been here as long as the land has been here. When the glaciers retreated, the ocean rose, and the rivers, coastlines, valleys and hills of Canada emerged and began to produce vegetation and attract fish and animals, there were people present.
My Peopling the Americas program was produced before CBC Radio went digital and began making all its programs available on the Ideas website. And I never wrote it up. Oh well.
Image: CBC News online.