By David Keys, London
February 24, 2006
THE ancestors of modern Europeans arrived on the continent up to 3500 years earlier than first thought and colonised it much more rapidly than once believed.
A combination of dating breakthroughs analysed in the latest issue of the science journal Nature is enabling archaeologists to push back the date for Homo sapiens' entry into Europe from 43,000 years to between 44,000 and 46,500 years ago.
The developments also reveal how modern humans crossed the continent from the Balkans to the Atlantic in 2500 years rather than 3500 years, as previously believed.
They would have met stiff resistance from the indigenous Neanderthal population as, generation by generation, they pushed westward as climatic conditions improved, said Paul Mellars, the author of the article.
"The two sides were competing for the same territories, the same animals and fuel supplies and occupying the same cave spaces," said the Cambridge University archaeologist.
"With that kind of competition, the Neanderthals were always going to come out as the losers."
Although other scientists have been pondering the implications of the revised radiocarbon dating, Professor Mellars' work is the first comprehensive review of the subject in a major journal.
For years it was thought that modern humans began arriving in western Europe at least 40,000 years ago and could have competed and mingled with the local population for at least 12,000 years. The revised dating of fossils and artefacts indicates the two species were in close contact for a shorter period.
Humans and Neanderthals, thought to have coexisted for 10,000 years across Europe, are more likely to have lived together for only 6000 years.
The new understanding of when, and how quickly, anatomically modern humans colonised Europe has been made possible by two recent pieces of research that have allowed scientists to push back the limits of chronologically accurate radiocarbon dating to 50,000 years ago, rather than 24,000 years.
Radiocarbon dating is a process of assessing age by counting radioactive decay of carbon in materials.
The studies of stratified radiocarbon in the Cariaco Basin, off Venezuela, and of radiocarbon on fossilised coral formations in the tropical Atlantic and Pacific have given scientists a better idea of the amount of carbon in the atmosphere over the past 50,000 years.
The work allows researchers to more accurately convert carbon years into calendar years.
The developments have also enabled archaeologists to push back the dates for the world's earliest cave paintings, in south-eastern France, from 29,000BC to 34,000BC.
Chris Stringer, human origins researcher at London's Museum of Natural History, said the Nature paper was an important step in the quest to map the spread of human populations.
"This study suggests that the period of potential interaction (between modern humans and Neanderthals) was short, and also favours the idea that the impact of the newcomers was indeed a significant factor in the demise of the Neanderthals, something which has been disputed recently," Mr Stringer said.