Carbon dating in the news
“I’ve been working in my area for 20 years, and just last month I found a data set I didn’t know existed,” says Andrew Martindale, an anthropological archaeologist at the University of British Columbia in Vancouver and director of CARD.
But the most compelling reason for a single large data set, says Kelly, is that it enables data mining.
Given enough properly dated archaeological finds, some experts argue that they can start to make careful population estimates and trace how human populations moved over space and time. Others argue that such data sets can be biased by archaeologists’ interests in particular areas or time periods: an abundance of radiocarbon dates in a given spot or time might reflect a researcher’s focus rather than real demographic change.
But the CARD database is getting large enough to iron out such factors, says Kelly.
Radiocarbon dating has long been used to reveal the age of organic materials — from ancient bones to wooden artefacts.
Scientists are now using the amassed dates for wider applications, such as spotting patterns in human migration.
The database currently holds 70,000 radiocarbon records from 70 countries.
The problem, says Bronk Ramsey, is that tree rings provide a direct record that only goes as far back as about 14,000 years.In 2015, Martindale and his colleagues used CARD to make the first continent-wide map of human occupation of the Americas over the past 13,000 years.Martindale plans to mine the data to confirm and quantify North American population changes due to wars or settlement relocations that are currently known only through indigenous traditional storytelling.The first such site should come online within the year.There are other radiocarbon databases out there, but CARD is by far the largest, says Robert Kelly at the University of Wyoming in Laramie, who is collecting data to contribute to CARD. “We’ve spent 60 years running radiocarbon dates, and you can do a lot with them if they’re all in one place.” Radiocarbon dating uses the ratio of stable carbon atoms to a radioactive isotope called carbon-14 in the material to determine the age of a once-living specimen.