The items that Dee and his colleagues studied were recovered from L’Anse aux Meadows decades ago and carefully stored in a freezer at the Parks Canada storage facility in Dartmouth, Nova Scotia, to fit the bill perfectly. It contains the bark of a tree that may have been pulled from the ground while clearing the land around the Viking site এবং and which, critically, still had its “bark edge” intact. Since there were 28 rings from the carbon-spike ring to the edge, the tree can be pruned in 1021 AD. )
A team of Dutch, German and Canadian scientists, led by D and his Groningen colleague Margot Quetimes, Study Inside Nature October 20. One of their colleagues is Canadian archaeologist Birgitta Wallace, who has worked on the site since the 1960s. Credit goes to De Wallace, who now, in his late seventies, has the presence of mind to preserve the wooden bits used in current research. “A lot of people will just chucked away from it. But he thought science could one day use them and put them in the fridge to keep them well for 40 years, ”he said.
“It’s a really nice piece of paper – it says this wood very precisely,” said Timothy Jules, a radiocarbon dating expert at the University of Arizona. Previously, the study used DendrochronologyThe science of determining the age of a tree from the relative growth rate recorded in its rings – requires a large number of cross-comparisons involving a large number of trees to calibrate a new specimen and come up with a (often fair) estimate of its age. “But in this case, they didn’t have to do it, because they have this spike that tells them exactly where they are [in the timeline]. That’s what makes it such a beautiful study, “said Jules.
Scientists have long believed that high-energy particles produced by other astrophysical sources, such as solar activity and supernovae, come to Earth in more or less steady currents. This means that the stable cousin ratio of carbon-14 will be fairly stable over time. But in 2012, a Japanese physicist, Fusa Mia, found a tree Carbon-14 spike dating from AD-774 to 775. Scientists now believe that a handful of these high-energy particles have exploded in the last 10,000 years.
Since these phenomena are very rare, researchers like D and his colleagues can be confident that they are not only seeing some random carbon-14 spikes, but a specific one – which means they can be confident about the date of attachment. Other spikes, Meanwhile, can be used to identify other historical events. (The same technique was recently used when a medieval church was built in Switzerland to pin the date from the study of its roof beams.)