An Oceanographic Perspective on Early Human Migrations to the Americas

• Published in: Oceanography
• Main Authors: Royer, Thomas C., Finney, Bruce
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: ODU Digital Commons 2020
• Subjects: Last glacial maximum; Human migrations; Younger dryas; Ice sheet thawing; Sea level; Coastal processes; Alaska; British Columbia; Archaeological Anthropology; Oceanography; United States History; Pacific; Ice Sheet; Beringia
• Online Access: https://digitalcommons.odu.edu/oeas_fac_pubs/386; https://doi.org/10.5670/oceanog.2020.102; https://digitalcommons.odu.edu/context/oeas_fac_pubs/article/1397/viewcontent/Royer_2020_AnOceanographicPerspectiveonEarlyHumanMigrationsOCR.pdf

Early migrants to the Americas were likely seaworthy. Many archaeologists now agree that the first humans who traveled to the Americas more than 15,000 years before present (yr BP) used a coastal North Pacific route. Their initial migration was from northeastern Asia to Beringia where they settled for thousands to more than ten thousand years. Oceanographic conditions during the Last Glacial Maximum (18,000-24,000 yr BP) would have enhanced their boat journeys along the route from Beringia to the Pacific Northwest because the influx of freshwater that drives the opposing Alaska Coastal Current was small, global sea level was at least 120 m lower than at present, and necessary refugia existed. The onset of the Bølling- Allerød warming period, between 15,000 yr BP and 14,000 yr BP, accelerated the melting of the Cordilleran Ice Sheet. Rapid increases in freshwater influx would have hindered travel along the coast of Alaska and British Columbia as global sea levels rose 14-18 m in 340 years, submerging refugia that had been used as haul-out locations. The northward- flowing Alaska Coastal Current accelerated, making southward movement along the coast less likely. An increase in the challenges to migration beginning with the Bølling-Allerød until the Younger Dryas (12,800-11,600 yr BP) likely occurred and could have resulted in a migration hiatus.