The ice-free corridor: Biogeographical highway or environmental cul-de-sac

As a theoretical concept, the ice-free corridor has given researchers a recognizable route for the Late Wisconsinan human colonization of the Americas. This dissertation reexamines that potential role by critically assessing plant and animal remains radiocarbon dated to between 9000 B.P. and 20000 B.P. To meet its theorized role as a north-tosouth Late Wisconsinan human migration route the corridor must fulfill two criteria: 1. that eastern Beringia could have supported human populations before Clovis appeared (- 11 500 B.P.) south of the ice sheets, and 2. that evidence from the corridor area shows that it was a biogeographic corridor capable of supporting human life. To fulfill these criteria 600 published radiocarbon dates were assessed for their reliability. This original number was reduced to 293 radiocarbon dates. The remaining dates were divided into four temporal periods and plotted spatially. Environmental inferences were determined from these distributions. The results support the first criterion: eastern Beringia could support human populations before Clovis. However, the results did not support the second criterion, and there is no evidence that a biogeographic comdor existed prior to 1 1500 BP. It was concluded that the ice-free corridor could not have been used as a north-to-south human migration route during the Late Wisconsinan. Therefore, other alternatives must now be considered to account for the arrival of Paleoindian cultures in southern North America.