Recalibrating the prehistory of Europe

[Daryl Habel]

In an article in the current (23 Februrary 2006) issue of Nature,
ABSTRACT HERE, Paul Mellars is touting the idea that advances in the science of radiocarbon dating are responsible for shrinking the overlap between the earliest 'modern' humans in Europe and the latest Neanderthals

Nature 439, 931-935 (23 February 2006) | doi:10.1038/nature04521

A new radiocarbon revolution and the dispersal of modern humans in Eurasia
Paul Mellars

Abstract
Radiocarbon dating has been fundamental to the study of human cultural and biological development over the past 50,000 yr. Two recent developments in the methodology of radiocarbon dating show that the speed of colonization of Europe by modern human populations was more rapid than previously believed, and that their period of coexistence with the preceding Neanderthal was shorter.

I haven't yet had the opportunity to read the full article, but from nature.com/news,it seems the two "recent developments" involve 1) ultrafiltration of bone samples, and 2) a recent analysis of sea sediments from Cariaco Basin near Venezuela, showing a more accurate record of  environmental14C fluctuations which, in turn, allows 14C radiocarbon calibration back to ca. 50,000 years.

"....Now, however, as Mellars describes in this week's Nature, two key advances have put carbon dating back on the map. By 'ultrafiltering' bone samples to get rid of smaller molecules and retain only the larger ones, researchers can prepare far purer samples. And recent analysis of sea sediments from the Cariaco Basin near Venezuela have provided the most accurate record yet of how environmental carbon-14 levels have fluctuated, allowing the technique to be calibrated back to around 50,000 years...."

Moreover, although specific site/dating information is not included in any of the media reports I've read so far (let's hope for better in Nature), Mellars says the earliest 'modern' colonization of Europe must be moved back a few thousand years:

"....Previous dating had suggested that H. sapiens arrived in Europe 43,000 years ago, and covered the continent by 36,000 years ago. But the refined figures are 46,000 and 41,000 years, says Mellars - just 5,000 years to colonize an entire continent...."

For the full story from nature.com/newsCLICK HERE.

Less informative about the recent advances in 14C radiocarbon ultrafiltration and environmental 14C fluctuation calibrations, but a promotion of Mellars' ideas on Neanderthal extinction, is a news report from reuters.co.uk: HERE

Exactly how much of this 'rewriting' of previous dating "43,000 years ago"  to the "refined figures" of 46,000 years ago for the earliest arrival of 'moderns' in Europe is based on calibration is not really clear in my mind yet, but I'd question the "previous dating" of 43,000 years if Mellars is referring here to the equivocal Bacho Kiro human fossils, lithic assemblage, and dating.  I think I'll remain cautious about Mellars' theory of Neanderthal extinction, but optimistic about the prospect of advances in 14C radiocarbon technology ('ultrafiltration') and calibration to 50,000 years ago (the improved analyses of environmental 14C fluctuations) .

Dar

[Daryl Habel]

I've now acquired and taken a quick first reading of the Mellars article in the current issue of Nature.  It is clear that the previous and revised estimates for the earliest 'modern' humans in Europe are from calibrations of dating from sites Mellars has previously assigned to 'modern humans' (including Near East sites such as Boker Tatchit, and the European Balkan site Bacho Kiro.  One could argue the assignment of these sites to 'modern' human immigrants is somewhat tentative,  but Mellars has been a proponent of replacement from east-to-west  for as long as I've been reading him, and consistently uses Boker Tatchit and Bacho Kiro in his arguments. 

Aside from that, I like this paper.  Yes, the new advances (ultrafiltration of 14C bone samples and analyses of environmental 14C fluctuations from sea cores) are well explained (with references) and there are site graphs with previous uncalibrated radiocarbon dates compared with new calibrated dates.  One of the most important implications shown is that while older uncalibrated radiocarbon chronologies showed the east-to-west occupation of Europe (by Mellars'  "modern humans") took about 7,000 years (ca. 43 ka at Bacho Kiro to ca. 36 ka at Isturitz and Cueva Morin), the new calibration data from the analysis of sea cores and comparison with GISP2 shows Mellars' east-to-west immigration/colonization for the same sites is ca. 46 ka and ca. 41 ka (calibrated), or only about 5,000 years.  IOW, uncalibrated 14C dates of 36 ka are about 5 kyr too young, but uncalibrated 14C dates of 43 ka are only about 3 kyr too young.   Apparently, researchers are starting to get a better understanding of environmental 14C fluctuations at near upper limits of the 14C dating technique. 

So whether one buys into Mellars' replacement theory or not, I'd recommend this paper for the review of the recent advances made in solving the problems of accuracy in radiocarbon chronologies.  It's only 5 pages, well composed, and is easy  reading.

Dar

[trehinp]

Thanks Dar,

This is fascinating. Apparently, it has also an impact on dating of the oldest known Palaeolithic paintings in Chauvet Cave. I Will start a topic on the other Palanth board on Parietal and Mobiliary art as it is going beyond the purpose of this Archaeometry & Chronostratigraphy discussion.

Paul

[lagarvelho]

Paul and Dar:

I don't "buy into" *Mellars'* replacementist ideas; they seem a little too "pat" to me.  OTOH, Dar is correct that "finer tuning of C14 dating could be very exciting and meaningful.
Anne G

[Daryl Habel]

John Hawks, on his weblog,  has weighed in with a generally negative review of the Mellars paper:
CLICK HERE

According to Hawks, it's been a slow week and "none of this is news".  Probably so. For those keeping up with current events in paleo,  the advances  in radiocarbon technique (ultrafiltration) and calibration have been known for some time.   But  still news for some who don't keep current.  Hawks'  main objections are directed to the Mellars interpretation of the significance of these advances.  But further discussion of modern human occupation and the disappearance of Neanderthal in Europe probably should be conducted on the forum Prehistory Board as a separate subject.

Dar