To all,
As mentioned by shenzhou and SteveF, in the thread titled "The 400kyr-old Ebbsfleet elephant butchery site"
HERE, the current (July 2006) issue of the
Journal of Quaternary Science HERE is a tribute to the late John Wymer, and is chock-full of excellent articles, only one of which I will single out in this thread.
http://www3.interscience.wiley.com/cgi-bin/abstract/112664030/ABSTRACTJournal of Quaternary Science
Volume 21, Issue 5 , Pages 557 - 573
AMS radiocarbon dating of Middle and Upper Palaeolithic bone in the British Isles: improved reliability using ultrafiltration.
R. M. Jacobi 1 *, T. F. G. Higham 2, C. Bronk Ramsey 2
1Department of Prehistory and Europe, The British Museum, Franks House, 56 Orsman Road, London N1 5QJ, UK
2Oxford Radiocarbon Accelerator Unit, Research Laboratory for Archaeology and the History of Art, Dyson Perrins Building, South Parks Road, University of Oxford, Oxford OX1 3QY, UK
Abstract
Recent research at the Oxford Radiocarbon Accelerator Unit (ORAU) has shown that ultrafiltration of gelatin from archaeological bone can, in many instances, remove low molecular weight contaminants. These can sometimes be of a different radiocarbon age and, unless removed, may severely influence results, particularly when dating bones greater than two to three half-lives of 14C. In this study this methodology is applied to samples of Late Middle and Early Upper Palaeolithic age from the British Isles. In many instances the results of redating invite serious reconsideration of the chronology for these periods. Copyright © 2006 John Wiley & Sons, Ltd.
This article is very informative about the new technique AMS 'ultrafiltration' results obtained on bone samples dating from the late MP and early UP in the UK, and shows how previous AMS dates obtained on bone not subjected to this new pretreatment yield significantly younger dates than, in some cases from the same sample, dates obtained by 'ultrafiltration'. This reported improvement bears on the dating of several sites which are described in short paragraphs in this paper, but I'd specifically like to report here what Jacobi
et al. say about the new (and old) AMS dating at Kents Cavern, and comment on what it adds to the discussion on Palanth "Lincombian chronology and Kent's Cavern"
HERE, and the original thread "Kent's Cavern 4: chronology and taxonomy questioned???"
HERE.
Regarding the taxonomy of the Kents Cavern 4 (KC4) maxillary fragment and the previously obtained AMS direct dating of 30,900 +/-900 BP (OxA 1621), Jacoby
et al. say(2006:566), "However, two important questions need to be asked. First, is it certain that the fossil is indeed from an anatomically modern human? Second, can the accuracy of this radiocarbon determination be trusted? The first question cannot, at present, be answered, but it may be possible to extract DNA from one of the teeth. This may help to determine whether this fossil represents an anatomically modern human or a Neanderthal..."
So Jacobi
et al. isn't any help for the question of KC4 taxonomy. But they do suggest (a continuation of the same quote): "...As for the second, it is now apparent that the maxilla had been treated with thin water-soluble glue. Therefore OxA-1621 must be regarded as potentially unreliable" (Jacobi
et al. 2006:566).
So here, Jacobi
et al. have given their assessment of the previously-obtained direct-dated OxA-1621 as "potentially unreliable", and "To constrain the age of the maxilla, bones and teeth from above and beneath its find context in Trench C have been dated, and in some cases redated. The results are given in Table 6. Once again, where bones have been re-dated using ultrafiltered gelatin the ages are greater than those previously obtained. This is particularly the case with the cranial fragment of woolly rhinoceros found only a short way above the maxilla (compare OxA-6108 and 13965)" (Jacobi
et al. 2006:566-7).
OxA-6108 is the previously-obtained AMS date on the woolly rhinoceros cranial fragment and is 30220 +/-460 BP, while OxA-13965 is the new 'ultrafiltration' AMS date from the same sample and is 37200 +/-550 BP - the difference being some 7,000 years. Taken with the rest of the AMS series now available from Kents Cavern, Jacobi
et al. conclude (2006:567): "The age of the maxilla would seem to be between 35 and 37ka BP, that is much older than previously suspected."
I'll note only that this estimate of 35-37 ka is slightly younger than the "between 37,000 and 40,000 years" that was boosted a year ago in the This is Devon, UK news story that initiated the whole question of the taxonomy and chronology of KC4
HERE. Still, if OxA-1621 is considered "potentially unreliable", and the new 'ultrafiltration' AMS 'bracketed' dating is considered to be more representative for the date of KC4, it
is significantly older than previously suspected.
Which makes the taxonomic question more important, as KC4 has always been referred as evidence for the earliest AMH in the UK. Jacobi
et al. say "The artefacts from the depth range of the maxilla are very few but are Upper Palaeolithic. They cannot be attributed to a particular technology or culture". No help there, but according to Jacques' translation of the summary of the KC stratigraphy by Denis Vialou
IN THiS ENCYCLOPEDIA, the depth of the maxilla contained 'Lincombian' artefacts, presumably a Lincombian blade leaf-point, I'd reckon.
So, I don't think we've arrived at any new certainties here about the taxonomy and chronology of KC4, but the Jacobi
et. al. paper in the current
JQS does fill in a few missing blanks about what is known, gives their reason for considering the 30ka date for KC4 "potentially unreliable" and, as I mentioned earlier, does provide a very informative update on results from this new AMS 'ultrafiltration' technique as obtained from many other sites in the UK, not mentioned by me here, but well worth reading.
Dar
