Wednesday 3 April 2013

It's About Time! El Sidrón Neanderthals are 49 kyr old, not 10


I truly believe that Tom Higham can leap tall buildings in a single bound. Well. Maybe not. But he has served notice to the palaeoanthropological community that there's a new sheriff in Temporal Town.
Photo credit: Nel Acebal, Elcomercio.es
Today Phys.org alerted me to the existence of new, more accurate and precise dates for the El Sidrón (Asturias, Spain) Neanderthals. And, once again, as it was at Kents Cavern and elsewhere, T.F.G. (call me Tom) Higham's (Oxford) is the fount of this new information on old stuff. Using an ultrafiltration pre-treatment protocol on Neanderthal bone, the team is now reporting that they've obtained a date of 48,400 ± 3200 bp (OxA-21 776).
Tom Higham
WOOD, R. E., HIGHAM, T. F. G., DE TORRES, T., TISNÉRAT-LABORDE, N., VALLADAS, H., ORTIZ, J. E., LALUEZA-FOX, C., SÁNCHEZ-MORAL, S., CAÑAVERAS, J. C., ROSAS, A., SANTAMARÍA, D. and DE LA RASILLA, M. (2013), A NEW DATE FOR THE NEANDERTHALS FROM EL SIDRÓN CAVE (ASTURIAS, NORTHERN SPAIN). Archaeometry, 55: 148–158. doi: 10.1111/j.1475-4754.2012.00671.x
This should put the kibosh, once and for all, on the fantastic notion, propounded last year [and spectacularly amplified in the media---New York Times are you listening?], that the ancient artwork at El Sidrón Castillo* Cave might have been attributable to Neanderthals.  Recall that those claims were being raised because the dates obtained ranged from 10,000 to about 46,300 BP (Torres et al. 2010).

I refrained from saying much last year, mostly 'cause I figgered you might be getting bored listening to my naked [incessant, really] scepticism about any claims of Neanderthal sophistication. But now I can say that nobody, perhaps not even the excavators themselves, thought such an amusing suggestion might have been the reality.

In addition to quashing the notion that Neanderthals in Spain were artistically precocious, this new date pretty much closes the door on the idea of an Iberian refugium for late-surviving Neanderthals.

I know. I know. I'm as naïve about radiocarbon physics as I am about anybody else's radiometric dating prestidigitation. So, how is it that I can so readily accept some results and not some others. Some might call this unscientific. My expectations are based on a certain familiarity with the corpus of knowledge surrounding the Neanderthals. And it's not scientific, for a very logical [philosophically speaking] reason. What's known in philosophy of science as the contexts of "discovery" and "justification"[i.e. how we arrive at our hypotheses and how we support or refute them] are almost always independent of one another. Thus, even if I literally dreamed up an idea, it's nevertheless subject to instantiation and later justification [A.K.A. hypothesis testing]. Getting back to the physics, in this case the mostly likely outcome was achieved [as far as my dreams are concerned], and by someone [and his technique] about which no one that I know [or know of] would [or could] dispute. In today's example, there's nothing like the uncertainty of provenance or of technique that I see, for example, in the luminescence dates from southern Africa. For that reason, if for no other, I have no aversion to hanging my hat on Higham's test tubes, and getting on with my business.

You know how much I hate saying "I told you so." There! I didn't say it.

* In the original version I erroneously identified the art as having been at El Sidrón. It's El Castillo. The substance of the comment remains the same---the Neanderthals, in all likelihood, were nowhere to be seen when the artwork was being created at El Castillo.


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8 comments:

  1. Obviously you have a crush on Tom Higham, Rob, and Tom Higham is great, but give credit where credit is due. The paper's lead author is Rachel Wood. Ultrafiltration was developed at CAMS Lawrence Livermore back in the 1980s by Tom Brown, John Southon and others, not by Tom Higham in the last decade. Many of the methodological developments in ultrafiltration at Oxford preceded Higham's tenure there and are associated with Robert Hedges, Christopher Bronk Ramsey, Fiona Brock and others in that lab.

    What Tom is doing very effectively is applying the method to important and interesting questions about human evolution, and that's certainly one of his talents. But it's important to recognize all the hard work that that whole group puts into these studies.

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  2. Well, you've got me there, Spawn. They say ignorance is bliss. No wonder I've been feeling so good, lately!

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  3. wait, people were saying there were 10,000 year old Neanderthals?

    how does that work? I'm confused.

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  4. Right you are, Anon. A 10,000 year old Neanderthal would indeed be extraordinary. The longest I've ever heard anyone suggest that they lived is about 35. ;-) But seriously, folks. Yep. Torres et al. 2010 report a date on a Neanderthal tooth that's just over 10 Kyr.

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  5. Having read the article of Torres et al. 2010, I couldnt find any 'report' claiming that the SID-3A tooth dating back to 10.340 +/- 70 ka is that of a Neandertal. The authors have adressed it as hominid molar.

    So I was wondering, how you came up with a Neandertal origin?

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  6. Hi, Anonymous.

    I fully understand why anyone might be confused by the equivocal 'picture' that arises from the two cited articles. However, both Torres et al. (2010) and Wood et al. (2013) are definite that the bipedal ape remains from the cave of El Sidrón are those of our close relations, the Neanderthals. Yet, curiously, in their Table 1, Torres et al. (2010) list the fossil remains as "Hominid."

    For that reason I can't fault you for being a little unsure about the species to which SID-2A and SID-3A are ascribed. Nevertheless, the directly dated Neanderthal fossils from El Sidrón range in age from about 10,270 at the low end of the range to above 50,000 at the high end (Torres et al. 2010).

    Thus, Wood et al.'s (2013) abstract is correct when it states that "direct radiocarbon dates on the human fossils [in the 2010 paper] were inconsistent, ranging between 10,000 and 50,000 BP."

    Thanks for visiting. You're welcome any time.
    rhg

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  7. Sorry for the late reply, I only recently saw the post. Spawn of Endra is not quite correct on a few points. First, the ultrafilter method was initially applied to collagen destined for radiocarbon dating in Simon Fraser university, BC, not in Lawrence Livermore, and the work was mostly done by Tom Brown, who was working on it for his doctoral dissertation. Of course ultrafiltration is an old technique (first reference 1907) and in use in science in a range of industrial filtering and membrane applications since that time. In Oxford, we started tested this method in 2000. It was Mike Richards (formerly in BC and a DPhil student in Oxford at the time) who was a key mover in beginning the first stages of testing the method once again in our lab. I arrived in early 2001 and we continued testing, and then applying it specifically on Palaeolithic bones, steadily chipping away at a series of what seemed to be strange dates in the literature (many which had been previously dated in our laboratory). Our first paper on this was in 2004 (Bronk Ramsey et al.) and later in 2006 (Higham et al.). Fiona Brock started with us in 2005.
    Spawn is right that methodological developments in labs are team efforts, and the result often of groups of people working together. Our lab is no exception. We are fortunate to have had, and to have, many bright young students who develop and improve the radiocarbon method. We always cite Brown et al. (1988) in our publications when discussing ultrafiltration, although we know now that the technique is not without its potential problems, and certainly when dating old bone samples using radiocarbon it is key that corrections are made for lab background because with bone there are many more preparative stages. For this we use sample specific (bone) backgrounds (see Rachel Wood et al. 2011).
    Thanks for the Blog and comments on posts.

    ReplyDelete
  8. Sorry for the late reply, I only recently saw the post. Spawn of Endra is not quite correct on a few points. First, the ultrafilter method was initially applied to collagen destined for radiocarbon dating in Simon Fraser university, BC, not in Lawrence Livermore, and the work was mostly done by Tom Brown, who was working on it for his doctoral dissertation. Of course ultrafiltration is an old technique (first reference 1907) and in use in science in a range of industrial filtering and membrane applications. In Oxford, we started tested this method in 2000. It was Mike Richards (formerly in BC and a DPhil student in Oxford at the time) who was a key mover in beginning the first stages of testing the method once again in our lab. I arrived in early 2001 and we continued testing specifically on Palaeolithic bones, steadily chipping away at a series of what seemed to be strange dates in the literature (many which had been previously dated in our laboratory). Our first paper on this was in 2004 (Bronk Ramsey et al.) and later in 2006 (Higham et al.). Fiona Brock started with us in 2005.
    Spawn is right that methodological developments in labs are team efforts, and the result often of groups of people working together. Our lab is no exception! We are fortunate to have had, and to have, many bright young students who develop and improve the radiocarbon method. We always cite Brown et al. (1988) in our publications when discussing ultrafiltration, although we know now that the technique is not without its potential problems, and certainly when dating old bone samples using radiocarbon it is key that corrections are made for lab background because with bone there are many more preparative stages. For this we use sample specific (bone) backgrounds (see Rachel Wood et al. 2011).
    Thanks for the Blog and comments on posts.

    ReplyDelete

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