Researchers date earliest known Viking settlement in North America to 1021

THIS month, the Biden administration proclaimed Oct. 9 as “Leif Erikson Day” to celebrate Nordic Americans and the famed Viking leader and his crew, whom the White House called bold explorers “believed to have been the first Europeans to reach the shores of North America,” centuries before Christopher Columbus.

In the 1960s, scientists uncovered an early Viking settlement in L’Anse aux Meadows in Newfoundland. Using carbon dating, researchers determined a rough period - 990 to 1050 - when Vikings were there.

But now scientists at the University of Groningen in the Netherlands have used a new kind of radiocarbon dating to determine an exact year when they were in what is now Newfoundland: 1021, or one millennium ago.

In a study published Wednesday in the journal Nature, scientists analyzed radiocarbons embedded in the annual tree rings of three chunks of wood found at the Viking site.

Researchers already knew that the three wood samples came from three trees. They also knew that Indigenous people could not have cut the slabs, as the wood showed signs of a metal blade, which Vikings, and not local communities, possessed at the time. The ancient outpost was similar to Viking settlements found across the western coast of Norway, Iceland and Greenland, said Raymond Sauvage, a professor in the department of archaeology and cultural history at the Norwegian University of Science and Technology.

Moreover, scientists knew that a solar storm around 992 would have shot high-energy cosmic rays into the atmosphere - and that a higher-than-usual concentration of radiocarbons became embedded in every tree alive at the time.

So they analyzed the annual growth rings found in the chunks of wood at the Viking site. Sure enough, the three samples showed evidence of being around when the solar storm of 992 raged. Each wooden slab also had 29 subsequent growth rings - which signaled that the tree was cut in 1021, according to the study published Wednesday.