Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

Planet Earth

At the bottom of a Japanese lake, the key to more accurate carbon-dating

Not Exactly Rocket ScienceBy Ed YongOctober 19, 2012 6:00 PM

Newsletter

Sign up for our email newsletter for the latest science news

Lake-Suigetsu.jpg

Carbon-dating is a widely used technique that allows us to gauge the age of archaeological samples from up to 60,000 years ago. But it’s not a straightforward method. It relies on a radioactive version of carbon called carbon-14, which is formed in the atmosphere and is taken up by plants (and whatever eats the plants). Once these die, the carbon-14 in their bodies decays away at a steady, predictable rate. By measuring it, we can calculate how old an ancient sample is. But there’s a catch. The levels of carbon-14 in the atmosphere vary from year to year, so scientists need some way of assessing these fluctuations to correct their estimates. They need long-running timetables, where each year in the past several millennia can be “read”, but where true levels of atmospheric carbon-14 can be measured. And now, in the bottom of a Japanese lake, scientists have found the best such timetable yet. As I write in The Scientist:

The sediment of a Japanese lake has preserved a time capsule of radioactive carbon, dating back to 52,800 years ago. By providing a more precise record of this element in the atmosphere, the new data will make the process of carbon-dating more accurate, refining estimates by hundreds of years. The data will allow archaeologists to better gauge the age of their samples and estimate the timing of important events such as the extinction of Neanderthals or the spread of modern humans through Europe. “It’s like getting a higher-resolution telescope,” said Christopher Bronk Ramsey from the University of Oxford, who led the study. “We can look [with] more detail at things [such as] the exact relation between human activity and changes in climate.”

Head over there for more.Image by Christopher Bronk Ramsey

    2 Free Articles Left

    Want it all? Get unlimited access when you subscribe.

    Subscribe

    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%

    Subscribe

    Already a subscriber? Register or Log In