Eastward Ho!

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Science  24 Sep 2010:
Vol. 329, Issue 5999, pp. 1575
DOI: 10.1126/science.329.5999.1575-c

Researchers have debated the timing and pace of the human colonization of the Americas, though it seems clear that a migration of Paleoindians into northeast Asia came first. The record of sites in this region should thus form a basis for evaluating the subsequent crossing into Alaska. Hamilton and Buchanan synthesize radiocarbon dates from nearly 150 sites across northern Eurasia and Alaska, ranging in age from about 45,000 to 11,000 years, and infer the expansion dynamics of modern humans into Alaska as well as Japan and Korea. Sites older than about 40,000 years appear only in southern Siberia; Japan, Korea, and much of the rest of Eurasia up to the western edge of Beringia (dashed line in the graphic) contain sites at least as old as 30,000 years. Afterward, there seems to have been a lull in expansion northward, coincident with the coldest temperatures and peak glacial expansion of the last Ice Age. Sites only appear within Beringia after about 16,000 years ago. The data support an overall slow rate of expansion of about 0.16 km/year and imply that North America was colonized only after the last glaciation.

PLoS ONE 5, e12472 (2010).

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