- Scientists re-dated a range of fossils from palaeolithic site Spy cave in Belgium
- They found fossils had been contaminated and so the original dates were wrong
- New dates place them up to 5,000 years older than the suspected 37,000 years
- This allowed the team to confirm that the Neanderthals disappeared from northwest Europe somewhere between 44,200 and 40,600 years ago Neanderthal remains discovered in a cave in Belgium thought to be 37,000 years old are actually thousands of years older than previous studies suggested, study shows.
University of Oxford archaeologists re-dated a number of Neanderthal specimens from Spy Cave in Belgium, a renowned site for palaeolithic discoveries and found contamination skewed earlier dating efforts.
The team say some bones previously dated at about 37,000 years old from within the cave may be up to 5,000 years older.
Determining that the bones were older than suspected allowed the researchers to confirm that Neanderthals disappeared from northwest Europe between 44,200 and 40,600 years ago - up to 8,000 years later than previous estimates.
Homo Sapiens arrived in Europe about 45,000 years ago, with the authors suggesting there 'must have been opportunities for cultural and genetic exchange.'
Neanderthal remains from Belgium have long puzzled scientists, according to the Oxford team, as fossil remains from the key site of Spy Cave suggested there were members of the nominin species living in the region 37,000 years ago.
This would place them among the latest surviving Neanderthals in Europe. But sample contamination might have affected these estimates.
Now, a team based in Oxford’s Radiocarbon Accelerator Unit has re-dated Neanderthal specimens from Spy Cave.
Most of the dates have been found to be much older than those obtained previously on the same bone samples - up to 5,000 years older in certain cases.
‘Dating is crucial in archaeology,' said Oxford Professor Tom Higham.
'Without a reliable framework of chronology we can’t really be confident in understanding the relationships between Neanderthals and Homo sapiens as we moved into Europe 45,000 years ago and they began to disappear.'
'That’s why these methods are so exciting, because they provide much more accurate and reliable dates,' he explained.
'The results suggest that Homo sapiens and Neanderthals probably overlapped in different parts of Europe and there must have been opportunities for possible cultural and genetic exchange.’
Lead author, Oxford-based, Dr Thibaut Devièse said the new chemistry methods for dating applied to the Spy allows for the fossils to be decontaminated.
He said we can 'decontaminate these key Neanderthal bones for dating and check that contaminants have been fully removed. This gives us confidence in the new ages we obtained for these important specimens.’
These results suggest that the bone had been preserved with a glue prepared from cattle bones and may have resulted in the earlier dates.
The team used an advanced method for radiocarbon dating fossil bones. Using liquid chromatography separation, they were able to extract a single amino acid from the Neanderthal remains for dating.
This so-called ‘compound-specific’ approach allows scientists to reliably date the bones and exclude carbon from contaminants such as those from the glue that was applied to the fossils.
These contaminants have plagued previous attempts to reliably date the Belgian Neanderthals because their presence resulted in dates that were much too young.
The results also highlight the need for robust pre-treatment methods when dating Palaeolithic human remains to minimize biases due to contamination, they said.
The team is now analysing archaeological evidence, such as bone tools, to further refine our understanding of the cultural transition between Neanderthals and Homo sapiens in this region.
Grégory Abrams, of the Scladina Cave Archaeological Centre in Belgium said they also re-dated specimins from two other sites in Belgium.
They were the Fonds-de-Forêt and Engis, and obtained similar ages to Spy.
'Dating all these Belgian specimens was very exciting as they played a major role in the understanding and the definition of Neanderthals,' Abrams said.
'Almost two centuries after the discovery of the Neanderthal child of Engis, we were able to provide a reliable age.'
The findings have been published in the journal Proceedings of the National Academy of Sciences.