Dating sites for scientists
Archaeologists vehemently disagree over the effects changing climate and competition from recently arriving humans had on the Neanderthals' demise.
The more accurate carbon clock should yield better dates for any overlap of humans and Neanderthals, as well as for determining how climate changes influenced the extinction of Neanderthals.
Israel Hershkovitz of Tel Aviv University Sackler Faculty of Medicine’s department of anatomy and anthropology.
Hershkovitz led an international team of anthropologists that included Prof.
The clock was initially calibrated by dating objects of known age such as Egyptian mummies and bread from Pompeii; work that won Willard Libby the 1960 Nobel Prize in Chemistry.
But even he “realized that there probably would be variation”, says Christopher Bronk Ramsey, a geochronologist at the University of Oxford, UK, who led the latest work, published today in Science.
Mina Weinstein-Evron of the University of Haifa’s Zinman Institute of Archeology, who discovered the ancient adult upper jawbone at one of the prehistoric cave sites in the area.
The scientists applied various dating techniques to the fossil to determine that the jawbone is at least 170,000 years old.
“This finding completely changes our view on modern human dispersal and the history of modern human evolution,” said Prof.Two distinct sediment layers have formed in the lake every summer and winter over tens of thousands of years.The researchers collected roughly 70-metre core samples from the lake and painstakingly counted the layers to come up with a direct record stretching back 52,000 years.Preserved leaves in the cores — “they look fresh as if they’ve fallen very recently”, Bronk Ramsey says — yielded 651 carbon dates that could be compared to the calendar dates of the sediment they were found in.The recalibrated clock won’t force archaeologists to abandon old measurements wholesale, says Bronk Ramsey, but it could help to narrow the window of key events in human history.