Ancient solar storm proves Vikings lived in Newfoundland by at least AD 1021, scientists say
A group of researchers from the Netherlands claim they've added to a pool of evidence proving the Vikings were the first known Europeans to cross the Atlantic and set foot on North American soil, erecting a small settlement on the north coast of Newfoundland at least 1,000 years ago.
The discovery builds on previous estimates from Canadian researchers, who unearthed the remnants of a small Norse village near St. Anthony, N.L., in the 1960s.
That theory made it into textbooks decades ago, but it wasn't until this year that scientists could offer hard evidence to support a precise date when the Norse actually lived there, according to Michael Dee, a geoscientist at the University of Groningen in the Netherlands.
The research, published this week in the scientific journal Nature, uses a radiocarbon-dating method so accurate, the team said they've pinpointed a single year in which the Vikings inhabited a grassy, windswept coastal area known today as L'Anse aux Meadows.
Using wood samples from that settlement, Dee was able to count the rings on each trunk, starting from a specific marker: a spike in carbon isotopes from an ancient solar storm that deposited a blast of cosmic radiation into the Earth's atmosphere in AD 993.
Trees around the world absorbed that extra radiocarbon, harbouring it inside their trunks and providing scientists with an accurate way to measure time using wood samples.
"There were moments in time where there were these sudden upsurges in radiocarbon … that pass through, into the trees, as a sort of pulse," he said. "We used that pulse."
Once the team detected that solar marker in old archeological findings, it was a simple matter of counting the trees' rings, from the year of the storm to when the tree was felled in AD 1021, Dee said.
The team also determined their samples were from trees chopped down with metal tools, which only the Vikings used, Dee explains — ruling out involvement by the ancestors of the Beothuk, the Indigenous people who lived in Newfoundland at the time.
The finding has now set the earliest known date that humans circumnavigated the globe, according to the report, completing a journey that began thousands of years earlier when nomadic peoples crossed over the Bering Strait from Asia.
Rare solar event confirms earlier findings
Radiocarbon dating isn't a new technology, Dee said. But it's only in the last couple of years that scientists became aware of the solar storm, a rare cosmic event that spiked radiocarbon levels in trees around the world only twice in the last 2,000 years.
That finding immensely bolstered the power of chronological analysis, he said, allowing them to apply the new dating method to the mystery of early European exploration. But it's not clear how long the Vikings remained in Newfoundland, or whether 1021 was the year they arrived, Dee said.
Dee credited Canadian researchers, whose work on the subject dates back nearly 50 years, with providing the basis of their discovery.
Birgitta Wallace, a retired archeologist with Parks Canada, helped excavate L'Anse aux Meadows in the 1970s, finding simple wooden structures that she says match Norse architecture in Iceland.
Using those findings and older carbon-dating technology, the Parks Canada team was able to estimate Viking arrival, dating it back to around AD 1000, give or take 100 years or so.
She also found the wood scraps that Dee's team used in their analysis, and preserved them without chemical treatment — just in case, one day, another group of researchers needed an untouched sample.
"We thought that in the future, there would be methods which we couldn't even think about at the time," Wallace said. "The exciting part, in a way, is not the excavation. It's when you analyze everything afterward and see what information you get out of it — what it leads to."
She placed a few samples in a freezer, where they've remained since 1976 — until the Netherlands team came knocking, future technology in hand.
"We did have a good idea that they would have been [in Newfoundland] from the late 10th century to the early 11th," she said. "But now they have a precise date — something we hardly ever get in archeology."
With files from Patrick Butler