PNAS lifts embargo on Neanderthal carbon dating paper after break
Due to an embargo break, PNAS is lifting the embargo early on the following paper. All other articles are under the scheduled embargo:
- Radiocarbon dating of Neanderthals’ presence in Iberia
Using a technique that removes impurities from samples prior to radiocarbon dating, researchers have established revised ages for fossils from southern Iberia and suggest that Neanderthals may not have held out in this region for as long as previously believed. Rachel Wood and colleagues screened 215 bones, previously excavated from 11 Iberian Paleolithic sites, for the preservation of collagen, the part of bone most suitable for radiocarbon dating. The authors found that only 8 bones from two sites, Zafarraya Cave and Jarama VI, yielded sufficient collagen for radiocarbon dating. One bone, which originated from a wild goat and was found in the Zafarraya Cave at a similar depth to Neanderthal fossils, was previously dated to approximately 33,300 years before present (BP), but when the authors cleaned the sample using ultrafiltration to remove carbon contaminants that can deflate a sample’s age, it was found to be more than 46,700 years old. Analyses of the remaining samples revealed ages that were at least 10,000 years older than previously determined, and that were close to or beyond 50,000 years BP, the upper limit for radiocarbon dating. The authors suggest that previous radiocarbon dates for Paleolithic materials from southern Iberia may be inaccurate, unless stringent decontamination protocols were used.
Article #12-07656: “Radiocarbon dating casts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia,” by Rachel E. Wood et al.
What likely broke the embargo is an AP story run by the News24.com site in South Africa, headlined “Neanderthals died before human arrival.” That story, which Mike Price of Science Careers sent me, was published at 17:49 local time, or about three hours before the scheduled embargo time of 3 p.m. Eastern.
I sent PNAS an email asking whether this was a break at 1:42 Eastern. They haven’t responded, but their email announcing the lift went out about 40 minutes later.
Update, 3:45 p.m. Eastern: PNAS responded shortly after this post went live to thank me for my message. I asked if there would be any sanctions, and will update with anything I hear back.