考古学：アメリカ大陸におけるバイキングの存在を正確に把握する

Vikings may have occupied the Americas as early as AD 1021, exactly 1,000 years ago, suggests a study published in Nature. Radiocarbon dating of wooden artefacts discovered at an archaeological site in Newfoundland, Canada, reveal what may be the earliest known record of humans crossing from Europe to the Americas.

Vikings were the first Europeans to traverse the Atlantic, settling at a site known as L’Anse aux Meadows on the northern peninsula of Newfoundland. Although early Europeans were known to have been present in the Americas around the time of the first millennium, the precise age of the settlement had yet to be determined.

Michael Dee, Margot Kuitems and colleagues report the analysis of a collection of wooden artefacts found within a Viking settlement at the L’Anse aux Meadows site. The authors are confident that these wooden artefacts belonged to Vikings, based on their location within the settlement and evidence for modification using metal tools, which were not manufactured by Indigenous people in the area at the time. The researchers were able to pinpoint the precise time of Viking occupation at L’Anse aux Meadows by using distinctive features of the atmospheric carbon record to determine exact radiocarbon dates for the felling of the trees from which the artefacts were made. In this case, an upsurge in atmospheric carbon caused by a cosmic-ray event in AD 993 acted as a reference point.

The AD 1021 date sets a new marker for European cognisance of the Americas, the authors claim. On a broader note, they highlight the potential value of studying cosmic-ray events — such as that of AD 993 in this study — as reference points in the future dating of artefacts and environmental events.