Why No 14C Dates for Blombos Cave’s MSA? Not Lobbing Aspersions. Just Sayin’ …

If I were a chess player I probably wouldn’t be trying this gambit. But I’m not. So, bear with me.

Worked bone, stone and ochre from Blombos Cave (Wikipedia)

I need help with a question that’s been nagging me for years. I’m curious to know if any of the bone artifacts from the Middle Stone Age (MSA) layers at Blombos Cave have been directly dated using AMS 14C. From my reading it appears not. In fact, it looks as if 14C was abandoned in favour of luminescence techniques once they had excavated deeper than those layers identified as Late Stone Age, the earliest of which were dated to give-or-take 39 ka BP. Everything below that is deemed to be MSA, and organic materials such as charcoal and bone were passed over in favour of grains of sand or burned flints in those strata. 
     Remember that, for most of us, MSA is synonymous with the Middle Palaeolithic in the rest of the world, and, for better or worse, it’s exclusively associated with the Neanderthals and their ilk, for which the jury is still out as to their cognitive equivalency with us modern types. Finding what are clearly modern human artifacts at Blombas Cave and elsewhere on the order of 30 to 50 ka earlier than anywhere else in the world has stunned and amazed scientists from Barrow to Burbank. But it’s never sat well with me. 

Location of Blombos Cave, South Africa (Credit)

     You and I know that 14C is perfectly capable of accurately gauging the age of organic materials until at least 50 ka, notwithstanding the need for calibration that corrects for environmental  and other effects. Why then do we have only luminescence age determinations for the sediments in which the Blombos Cave bone artifacts and charcoal were deposited? Henshilwood et al. (2002) provide some insight, although I’m not certain they realize that by doing so they’ve left themselves exposed to (at a minimum) questions about their decision.
     That (to me) curious decision is explained in what amounts to a throwaway comment, which I will quote here

In radiocarbon terms, the MSA at BBC is of infinite age (Vogel, personal communication).

The MSA levels are being dated using luminescence techniques: single-grain laser luminescence (SGLL), single aliquot optically stimulated luminescence (OSL and IRSL), multiple aliquot OSL on sediments and also TL of burnt lithics and electron spin resonance (ESR) of teeth (Henshilwood et al. 2002:638). 

Being the skeptical type, I was intrigued by what seemed to me to be such a weak citation as to the inefficacy of 14C beyond 39 ka–the date of the oldest LSA at Blombos. Just a ‘Vogel pers. comm.’ No reams of empirical evidence. No other justification. So I endeavoured to discover by what authority Vogel had made such a pronouncement.
     No doubt some among you will think it naïve of me, or worse, that I’m poorly informed and ill-prepared to be taken seriously by the palaeoanthropological establishment. Nevertheless, I had no prior knowledge of Vogel’s reputation in the radiocarbon world and in the South African archaeological community. His work includes a 1997 paper in Radiocarbon in which he attempted to calibrate 14C dates with U/Th dates within the same stalagmite from a South African cave. That work was superseded a few years later by the more widely cited Fairbanks et al. (2005), who honed the 14C calibration curve back to 50 ka using pristine corals from around the globe. Their findings are that 14C underestimates calendar years such that 45 RCYBP works out to 48,934 calendar years (give or take 500). By this means the calendar date of 39,200 BP from the lowest LSA level at Blombos would have been produced by a radiocarbon age of about 34 ka RCYBP (try it yourself by clicking here to go to Fairbanks’s calibration calculator).
     It would seem, therefore, that despite Vogel’s pronouncement, cited in Henshilwood et al. (2002), there is no physical limitation on dating organic material that is older than 39 ka (i.e 34,000 RCYBP), as long as its age doesn’t exceed 45 RCYBP. That would, theoretically, allow the excavator of Blombos Cave to extend use of 14C for at least a further 11,000 RCY beyond the earliest LSA from Blombos Cave. Surely some of the MSA materials could be presumed to date from this 11,000-year window.
     Directly dating the bone and charcoal from the upper MSA strata may prove nothing. However, knowing that there’s no theoretical limit on the use of 14C for that 11,000 year period leaves wide open the question as to why Chris Henshilwood hasn’t attempted to date, directly, some of his bone artifacts or charcoal from the MSA layers. It’s just possible that they would yield dates far younger than those produced by luminescence techniques (about which I’ve had a certain amount to say in previous efforts here at the Subversive Archaeologist).

From Henshilwood et al. (2002)

     After all, the MSA levels in Blombos (at least those illustrated in Henshilwood et al. [2002], shown above) appear to be quite shallow–the sort of depth that you could imagine accumulating in far less than the 35 ka that the luminescence dates would have you believe it took for them to accumulate–and it’s within reason to suspect that they could easily have been deposited in the 11 RCY or so before 39,200 BP.
     And so. For what it’s worth, I’m issuing a challenge from this lofty perch of mine. Chris, try dating some of your MSA bone using good, old-fashioned, AMS 14C and see what you get. A fair few of us are curious to know the result. 

The ‘MSA’ and Modern Humans: It’s Only a Matter of Time

What counts is not what sounds plausible, not what we would like to believe, not what one or two witnesses claim, but only what is supported by hard evidence rigorously and skeptically examined. Extraordinary claims require extraordinary evidence.   Carl Sagan 

BBC: Blombos Cave PPC: Pinnacle Point Caves KRM: Klasies River Mouth Cave

The southern African publishing machinery is in high gear when it comes to the so-called Middle Stone Age (MSA). It feels like there’s a new claim every week. In this case, similar claims’ve been made before. But this time it’s for … are you ready for this? It’s a big surprise, I know. But this example is…wait for it…Yes! The oldest piece of worked ochre ever reported! A-bloody-mazing! Those MSA people were modern humans for sure! And they were damned good at it, too, if I’m any judge! More on the ochre after I tell you why I’m telling you this.

     All the evidence points to these discoveries being the work of people like us–the skeletal remains from Klasies River Mouth at 75 to 125 kya (modern human, chins and all!), the Howieson’s Poort stone artifacts at Bombos Cave and elsewhere from about 65 to about 60 kya (to all intents and purposes like the Mesolithic of Europe with its backed blades), the beads, the ochre, pigment grinding tools, and more. 
     The MSA of southern Africa is nothing like the Middle Palaeolithic of most other regions. Quite simply, while the Neanderthals and skeletally modern humans in Europe, southwestern Asia and northern Africa were still hacking flakes off ‘Mousterian’ bifacial cores [or handaxes, if you prefer], sometimes taking smaller flakes off the edges to keep them sharp, and trying to rejuvenated their bifacial cores with a prepared platform and a might whack intended to split the core in two (often only resulting in the removal of just a final flake–a ‘Levallois’ flake [if you prefer]), the MSA people of SA were acting just like you and I would have (minus all of the industrial culture accoutrements like white wine [most likely] and Saturday morning cartoons on TV).

Howieson’s Poort lithics (Image credit)

    What to make of all this really early ‘industry?’ It’s not a trivial point. As far as the archaeological record of the rest of the world goes, these people, at 100 ka and more, were upwards of 60 ka ahead of the cultural curve of the rest of the world. So it’s an untrivial, and still open, question what kept people like us from doing, in the first 60 ka of modern human history, what members of the same species evidently did in an instant of geological time once we stepped outside of Africa. Let’s face it, after about 40 to 50 ka ago it was like modern humans were shot out of a cannon. Australia was reached in the blink of a geological eye. Europe? Same story. Eastern Asia? The same. And during an ice age, no less. Eat your hearts out, Homo erectus! Homo sapiens rules!

     As you might imagine, I’m troubled by all this precocious behaviour on the part of antipodean Late Pleistocene southern Africans. It’s a conundrum that I can’t get out of my head. And every time a new claim comes down the ‘pike I get more irked by my inability to explain it, or even to conjure up a plausible scenario. Believe me, this enigma is nothing like the other stuff that irks me [of which you’re all aware by now]. This is us–unequivocally modern–but it’s us when we shouldn’t be there. I know. I know. That’s not scientific, Rob. You should have an open mind. [That’s all well and good, but an open mind isn’t the same thing as an empty one–I need an answer, not a reminder of my shortcomings!]
     I’m confused, too, about use of the term Middle Stone Age for what is obviously the work of both skeletally and behaviorally (and cognitively) modern humans. Someone in the know might be able to help me here [if I could get the bleeping comments to work again!]. Is it called MSA because it’s older than a certain arbitrary cut-off on the geological time scale? Why don’t they just call it ‘Earliest Upper Palaeolithic’ or something like that? Somebody please explain!
     All of this very early modern human evidence from southern Africa reminds me a bit of the myriad claims for Pre-Clovis occupation of the Americas that have been erected, assailed, and finally collapsed under the weight of skepticism that usually accompanies such assertions. The artifacts are real. The dirt’s real. But something’s always wrong with the dates [except, perhaps, Calico Hills, where the eye of the beholder was just too clouded by its infatuation with broken rocks to see the forest for the trees]. That’s the way it always ends, with a dying fall. The claims, one after another, are justifiably questioned. No resolution. But the claims fall by the wayside, and no one makes an effort to get them back in the mainstream. It’s happened over and over and over again. My strong suspicion is that it’s happening in South Africa, but without the questions, without the doubt. And that, alone, worries me, and suggests that there’s a systemic problem.
     I have a fearless prediction. One day either the late dates for everything outside of Africa are going to be shown to be too young, or the inverse will prove to be the case. I think you know where my money is.
     One final thought. For years it’s been the orthodoxy to think of the human lineage as having been on a slow march from ape-dom to humanity. You’ve heard it. Sure you have. For ‘99% of human history we were egalitarian hunter-gatherers.’ [Stan: I remember you saying that in Old World back in ’86–no shame implied. It has been the mantra for decades.] Then agriculture happened and we all went to Hell in a hand-basket and we ended up (some of us) Capitalists, and look where that’s gotten us! [Ruth: I’ve always had a bone to pick with that one!]
     What if we weren’t human until recently? In a way I think it lets us off the hook. After all, the first stone artifacts are 2.5 MILLION years old. If we’ve been thinking like we do now for 2.5 million years, I’d say we probably don’t deserve to survive as a species, given the mess we seem to have made of things in just a few tens of thousands of years. BUT, if we only became human give or take 40,000 years ago, and if the first 30 of those were spent coping with an ice age, that means we’ve only had about 10,000 years to figure things out. I like that better. Because I think we’re better than the long chronology paints us. I like to think that we’ve come a LONG way in 10 ka.   
     Think of it. Domestication at give or take 10. Cities and monumental architecture, art, writing, by, say, 8 or so. Philosophy, drama, mathematics, geometry, science, by 4 or so. I mean, if you look at it from the short chronology point of view, we look a lot better. I’d hate to think that we’d been at this whole human thing for 100,000 years.
     We’d seem REALLY pathetic.

Back to the ochre that persuaded me to write the above. With all due respect to Francesco d’Errico, Renata García Moreno, and Riaan F. Rifkin, authors of ‘Technological, elemental and colorimetric analysis of an engraved ochre fragment from the Middle Stone Age levels of Klasies River Cave 1, South Africa‘ (Journal of Archaeological Science, 39, 942–952, 2012), I fail to see why this publication is so effing important. Imagine someone in Europe publishing this: ‘Ooh, ooh, another piece of ochre from the Upper Palaeolithic of France!’ They’d be laughed out of the academy–even if it were the oldest such artifact ever found. So, forgive me if I’m less than fired up about this amazingly complex and scholarly article about a lump of iron oxide with a bunch of scratches on it. Mind you, if the scratches spelled out the first five verses of Genesis, there might be a story there. Otherwise…yawn.

From d’Errico, Moreno and Rifkin 2012

I hope this, my attempt to explain more of my mystification with the MSA of southern Africa, hasn’t kept any of you from your naps!
     Be well. Have a good weekend. Thanks for dropping by.