Radiocarbon dating — a key tool used for determining the age of prehistoric samples — is about to get a major update. For the first time in seven years, the technique is due to be recalibrated using a slew of new data from around the world. The result could have implications for the estimated ages of many finds — such as Siberia’s oldest modern human fossils, which according to the latest calibrations are 1,000 years younger than previously thought.
The work combines thousands of data points from tree rings, lake and ocean sediments, corals and stalagmites, among other features, and extends the time frame for radiocarbon dating back to 55,000 years ago — 5,000 years further than the last calibration update in 2013.
Archaeologists are downright giddy. “Maybe I’ve been in lockdown too long,” tweeted Nicholas Sutton, an archaeologist at the University of Otago in New Zealand, “but … I’m really excited about it!”
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Opportunities to refine and extend methods of dating are always eagerly anticipated. The level of expressed exuberance may indeed be influenced by the quarantine, however, as the refinement will not be as radical as the report may make it seem. The 2013 calibration update already included “tree rings, lake and ocean sediments, corals and stalagmites,” but the updated calibration data set may include additional sources or more precise measurements of previously analyzed samples.
Most calculated ages will not significantly change with the new calibration data. Substantive changes are most likely for samples with 14C contents that correspond to calibration plateaus (variations in ancient atmospheric 14C production resulting in multiple possible dates for a sample with a particular residual 14C-content). I am not specifically familiar with the Siberian human fossils, but this may be an example.