A chemical dating technique worked with unprecedented accuracy when tested on lava from the Vesuvius volcano eruption that destroyed the ancient Roman city of Pompeii, researchers report.
In a study published Friday in the journal Science, scientists at the University of California, Berkeley, say they used specimens from the Vesuvius explosion, known to have happened in A.D. 79, to validate the accuracy of the widely used radioactive-argon dating system.The results pinpointed the volcanic eruption at 1,925 years ago, off by just seven years from the date recorded by historians.
Other experts said the experiment was an important technical achievement because it was able to accurately establish the age of some of the youngest material ever tested.
"We set out to date the very youngest thing we could in order to push the limits on this technique," said Paul R. Renne, first author of the study. "This was kind of a ground truth test."
The Vesuvius eruption suddenly buried Pompeii and some other Roman cities, trapping people in their homes and workplaces. Pompeii, not far from Naples in present-day Italy, has since become one of the most celebrated archaeological digs in the world because it provides such a clear picture of how people lived in the first century.
Ancient Roman historian Pliny the Younger wrote about the eruption, saying it occurred on the afternoon of what in modern calendars would be Aug. 24, A.D. 79, or 1,918 years ago.
With the undisputed accuracy of this date as a target, Renne said his team used the radioactive-argon dating technique on volcanic rock from Pompeii.
Renne said the result of 1,925 years has a scientific error range of plus or minus 94 years.
"We nailed the date to 5 percent on our first attempt, so we could probably get the error down to 1 percent or less," he said.