The coastal migration hypothesis is one of two leading hypotheses about the settlement of the Americas at the time of the Last Glacial Maximum. It proposes one or more migration routes involving watercraft, via the Kurile island chain, along the coast of Beringia and the archipelagos off the Alaskan-British Columbian coast, continuing down the coast to Central and South America.[1][2] The alternative is the hypothesis solely by interior routes, which assumes migration along an ice-free corridor between the Laurentide and Cordilleran ice sheets during the Last Glacial Maximum.
The coastal migration hypothesis has been bolstered by findings such as the report that the sediments in the Port Eliza caves on Vancouver Island indicate the possibility of a survivable climate as far back 16 ka (16,000 years) in the area, while the continental ice sheets were nearing their maximum extent.[3] Despite such research, the hypothesis is still subject to considerable debate.[4][5] Carlson,[6] Erlandson,[7] and others have argued for a coastal migration from Alaska to the Pacific Northwest pre-11ka (before ≈13,000 calendar years ago) that predates the hypothesized migration of Clovis people moving south through an ice-free corridor located near the continental divide.[8] The coastal migrants may have been followed by the Clovis culture when the final retreat of the Cordilleran Ice Sheet opened migration routes between interior and coastal Alaska.
A 2017 discovery on Triquet Island by an archaeological team from the University of Victoria appears to verify local First Nation oral history traditions that the island was inhabited during the ice age.[9] A hearth excavated at the site was determined by radiocarbon dating to be between 13,613 and 14,086 years old, making it one of the oldest settlements in North America.[10]
While some archaeologists believe that the Clovis people moved south from Alaska through an ice-free corridor located between modern British Columbia and Alberta, recent dating of Clovis and similar Paleoindian sites in Alaska suggest that Clovis technology actually moved from the south into Alaska following the melting of the continental ice sheets at about 10.5 ka.[11]
In North America, the earliest dog remains were found in Lawyer's Cave on the Alaskan mainland east of Wrangell Island in the Alexander Archipelago of southeast Alaska; radiocarbon dating indicates it is 10,150 years old. A genetic-based estimate indicates that this dog's lineage had split from the Siberian Zhokhov Island dog lineage 16,700 years ago. This timing coincides with the suggested opening of the North Pacific coastal route into North America.[12]
... Alternatively, the coastal migration hypothesis suggests that people migrated along the southern edge of the exposed Beringian shelf and down the Pacific ...
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... A multi-disciplinary study at Port Eliza cave on Vancouver Island has refined the timing and character of late Wisconsinan environments and has significant implications for the human Coastal Migration Hypothesis ...
... Recent discoveries and events have breathed new life into the coastal migration theory, which suggests the opposite of the ice-free corridor hypothesis—that maritime peoples first traveled around the North Pacific Coast then followed river valleys leading inland from the sea. Having a coastal route available does not prove that such a maritime migration took place. Archaeological evidence for early boat use from islands along the western margin of the Pacific may support the idea that such a journey was technologically feasible, but archaeological data from the Pacific coast of North and South America are presently ambiguous about the origins of the earliest coastal occupants. ...