"First Americans" article

Scientific American’s November issue has a cover story on the peopling of the Americas, by Heather Pringle, and it has gone online for free: (UPDATE 2006-10-23: Well, that’s strange. I read it for free at the link, but now it has gone to paywall. Rats.) “The First Americans: Mounting Evidence Prompts Researchers to Reconsider the Peopling of the New World”. The article reviews several Clovis and pre-Clovis news stories from last spring, including some that I covered at the time (“Early New World archaeology news”).

Among the stories recounted is an attempt to redate the opening of the “ice-free corridor” between the Cordilleran and Laurentide ice sheets. The closure between these sheets has been argued to block overland migration into North America before Clovis times. Some geologists are now arguing for an earlier date.

The big question now is whether the entire corridor lay open during this period, particularly the section to the north. Munyikwa thinks it did. His team recently dated sand dunes farther north, along the Alberta-Northwest Territory border, with similar results. These data, Munyikwa says, fit current thinking about the Laurentide ice sheet. The general consensus among geologists, he notes, is that the ice sheet retreated in a northeasterly direction as a wide front, as opposed to [moving] in discrete lobes. We envisage that the deglaciated land extended to the north. If so, explorers from Asia could have entered the corridor around 15,000 years ago, nearly 1,000 years after the route to the western coast opened.

Not much on the genetics in the article, and now I think it will be interesting when ancient genomics reaches the New World.