Radiocarbon dating flaws
One of the most important dating tools used in archaeology may sometimes give misleading data, new study shows - and it could change whole historical timelines as a result.
Because it is radioactive, carbon 14 steadily decays into other substances.Levels do happen to spike on a local and seasonal basis with changes in the carbon cycle, but carbon-14 is presumed to diffuse fast enough to ignore these tiny bumps.At least, that was the assumption until now."We know from atmospheric measurements over the last 50 years that radiocarbon levels vary through the year, and we also know that plants typically grow at different times in different parts of the Northern Hemisphere," says archaeologist Sturt Manning from Cornell University."So we wondered whether the radiocarbon levels relevant to dating organic material might also vary for different areas and whether this might affect archaeological dating."The tree rings were samples of Jordanian juniper that grew in the southern region of the Middle East between 16 CE.This carbon – which has an atomic mass of 14 – has a chance of losing that neutron to turn into a garden variety carbon isotope over a predictable amount of time.By comparing the two categories of carbon in organic remains, archaeologists can judge how recently the organism that left them last absorbed carbon-14 out of its environment.