A story in Science last week reported new findings from Lake Suigetsu in Japan, that promise to allow a better refinement of the radiocarbon dating method.
Lake Suigetsu. Image courtesy of Christopher Bronk Ramsey
Radiocarbon dating is only feasible for the past 50,000 years, and it is not what you might call precise: the dates are based on the carbon content of the atmosphere, which has fluctuated over that period. Luckily, we have tree ring data for the past 13,000 years or so, that allows us to calibrate radiocarbon dates. Trees maintain a record of carbon 14 in their growth rings: very convenient, but up until now, anything older than 13,000 years has been based on fragmentary data.
24,700 year-old leaf dated by radiocarbon. Image courtesy of Richard Staff
Lake Sugietsu in Japan has an annual record of dated organic materials back to the feasible limits of radiocarbon, and once researchers like Paula Reimer get their calculations done, we'll have a pretty solid data set on carbon fluctuations in the past, and a brand new calibration set to use.
- More on Radiocarbon Calibration
- More on Radiocarbon Dating
Bronk Ramsey C, Staff RA, Bryant CL, Brock F, Kitagawa H, Van der Plicht J, Schlolaut G, Marshall MH, Brauer A, Lamb HF et al. 2012. A complete terrestrial radiocarbon record for 11.2 to 52.8 kyr B.P. Science 338:370-374.
Reimer PJ. 2012. Refining the radiocarbon time scale. Science 338:337-338.
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