Age of Viking settlement revealed using trees and astrophysics

The Vikings reached North America long before Columbus' enslavement and brutalization of the Americas' Indigenous population, the Viking settlement at L'Anse aux Meadows, Newfoundland, was discovered six decades ago. Though many of the settlement's structures have been recreated, as accurately as dig site evidence and historical research could allow, the settlement's date has been difficult to place exactly.

Until now.

According to a new study published in Nature, scientists from a number of disciplines have been working together to see the mystery of the L'Anse aux Meadows put to bed. It's complicated stuff, and I am tired. So, I went looking for a dumbed down version of the study to help explain it all.

The New York Times does not disappoint.

According to The 'Times, the team working to date the site started things off by collecting samples of three pieces of wood, from around L'Anse aux Meadows, to be sent off to a lab for a bit of time under a microscope.

From The New York Times:

Back in the laboratory, Dr. Kuitems cut a tiny amount of wood from each tree ring of each piece… Working those samples — each representing one year of tree growth — the team isolated the carbon within the wood. All that carbon originally came from Earth's atmosphere.

The vast majority of the carbon in the atmosphere is carbon 12, a stable atom with six protons and six neutrons. Only a fleeting fraction is radioactive carbon 14, also called radiocarbon. That isotope of carbon is produced when cosmic rays — high-energy particles from the sun or beyond the solar system — interact with atoms in Earth's atmosphere. Scientists who study cosmic rays used to think that these particles arrived in a relatively constant barrage, meaning that the ratio of carbon 14 to carbon 12 in the atmosphere has largely remained steady over time.

Here's where the neat stuff begins.

Some time ago, a physicist by the name of Fusa Miyakea discovered that couple of tress in his native Japan were holding on to high amounts of radiocarbon. As it turns out, instances of finding such high amounts of radiocarbon in wood are pretty damn rare: only a handful of such events have been able to cause it, in the past 10,000 One of of those events occurred during the Viking Age, somewhere in the ballpark of 992 A.D. to 993 A.D., with high levels of radio carbon seeping into trees all around the planet.

With all of this in mind, the team set to work, using two great tastes that taste great together—the study of tree rings (dendrochronology) and astrophysics—to finally nail down a precise date.

Again with The New York Times:

The researchers found that their three pieces of wood all exhibited a pronounced increase in radiocarbon that began 28 rings before their outer bark. Ring 28 must correspond to the year A.D. 993, the team concluded. They ruled out earlier and later Miyake events based on the carbon 14 to carbon 12 ratios measured in the wood, which vary in known ways over centuries.

With a date now pinned to an inner tree ring, "all you need to do is count to when you get to the cutting edge," Dr. Dee said. The three pieces of wood the team analyzed were all felled in 1021, the researchers calculated

Pretty fucking cool.

Image via Flickr, courtesy of Douglas Sprott