Thursday, February 16, 2023

         ONE STEP FOR A MAN, ONE GIANT STEP
                 BACKWARD FOR MEGAFAUNAKIND

 PNAS RESEARCH ARTICLE


OPEN ACCESS

Ice and ocean constraints on early 

human migrations into North America

along the Pacific coast

Summer K. Praetorius https://orcid.org/0000-0003-2683-3652 spraetorius@usgs.gov, Jay R. Alder https://orcid.org/0000-0003-2378-2853, Alan Condron https://orcid.org/0000-0002-7337-1713, and Jon M. Erlandson https://orcid.org/0000-0002-4705-4319
 
Growing evidence for a human presence in the Americas prior to 15,000 y ago—when ice sheets blocked transit through the continental interior—imply a Pacific Coast route was the more likely pathway for dispersals from Beringia into North America between ~26,000 and 14,000 y ago. The feasibility of coastal migration at various times depended on the extent of Cordilleran glaciers, sea ice, the strength of ocean currents, and the productivity and availability of marine and terrestrial resources. 
Based on paleoclimate records and climate models, we estimate that 24,500 to 22,000 and 16,400 to 14,800 y ago were the most environmentally favorable time windows for a coastal migration during the period when the interior route was blocked.
     February 6, 2023


https://doi.org/10.1073/pnas.2208738120


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