Abstract
The timing of the first entry of humans into North America is still hotly debated within the scientific community. Excavations conducted at Bluefish Caves (Yukon Territory) from 1977 to 1987 yielded a series of radiocarbon dates that led archaeologists to propose that the initial dispersal of human groups into Eastern Beringia (Alaska and the Yukon Territory) occurred during the Last Glacial Maximum (LGM). This hypothesis proved highly controversial in the absence of other sites of similar age and concerns about the stratigraphy and anthropogenic signature of the bone assemblages that yielded the dates. The weight of the available archaeological evidence suggests that the first peopling of North America occurred ca. 14,000 cal BP (calibrated years Before Present), i.e., well after the LGM. Here, we report new AMS radiocarbon dates obtained on cut-marked bone samples identified during a comprehensive taphonomic analysis of the Bluefish Caves fauna. Our results demonstrate that humans occupied the site as early as 24,000 cal BP (19,650 ± 130 14C BP). In addition to proving that Bluefish Caves is the oldest known archaeological site in North America, the results offer archaeological support for the “Beringian standstill hypothesis”, which proposes that a genetically isolated human population persisted in Beringia during the LGM and dispersed from there to North and South America during the post-LGM period.
Highlights
A vast region stretching from the Lena River in Siberia to the Mackenzie River in the Yukon Territory [1, 2], is thought to have played a pivotal role in the initial dispersal of human populations from Asia to North America
Our taphonomic analysis indicates that wolves, lions and, to a lesser degree, foxes were the main agents of bone accumulation and modification, but that humans contributed to the bone accumulations in both caves, partially confirming earlier taphonomic studies [26, 39]
In other Beringian archaeological sites dated to the Late Pleistocene/Early Holocene, taphonomic studies show that cut marks are scarce [73] or even absent in bone assemblages highly affected by natural processes [74, 75]
Summary
A vast region stretching from the Lena River in Siberia to the Mackenzie River in the Yukon Territory [1, 2], is thought to have played a pivotal role in the initial dispersal of human populations from Asia to North America. Recent genetic and palaeogenetic analyses [3,4,5,6,7,8,9,10], as well as dental morphological evidence [11], confirm that human populations migrating into North America originated in Siberia. They suggest that dispersing groups reached Beringia during the LGM PLOS ONE | DOI:10.1371/journal.pone.0169486 January 6, 2017
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