Prof Christopher Ramsey

Abstract:

The Bayesian calibration program OxCal v.4.1.5 is applied to two chronological datasets for early Lapita derived from two comprehensive reviews. The two datasets are supplemented by published ages for early Lapita sites in two key island groups within Remote Oceania: Vanuatu and Fiji. The analyses provide statistically robust chronologies for the emergence of Lapita on Mussau at 3470-3250 cal BP and in the rest of the Bismarck Archipelago at 3360-3240 cal BP. After a period of 130-290 years, Lapita dispersed to Vanuatu by 3250-3100 cal BP and to Fiji by 3130-3010 cal BP.

Abstract:

Single and multiphase models have been used extensively in construction of chronologies. We model more gradual transition between phases with a trapezoid model since it better reflects the nature of the information that goes into the model prior. We find that a simple trapezoid model has a bias that does not reflect prior knowledge, and thus propose an addition of a noninformative element to the prior. We also present an alternative parameterization, which transforms the current abrupt transition model into a model that allows for gradual changes. The addition of a noninformative prior ensures model flexibility. We evaluate these Bayesian models using 2 case studies. © 2012 by the Arizona Board of Regents on behalf of the University of Arizona.

Abstract:

Hublin et al (2012) have published a new series of AMS determinations from the site of the Grotte du Renne at Arcy-sur-Cure, one of the key sites in discussions regarding late Neanderthal behavior and adaptation. The site is well known as one of the very few Châtelperronian sites that appear to contain evidence for the range of ornaments and objects that are usually found in sites of the Proto- or Early Aurignacian in Europe, and therefore associated with anatomically modern humans. For this reason it is important that we have an idea of the chronology of the sequence here, so that we may compare it with other contexts where similar cultural horizons have been excavated. Higham et al (2010) published a series of 31 AMS dates from well-selected humanly-modified material from several layers of the site. They found variation in the results that they ascribed to taphonomic influences, which implied strongly that there was some degree of mixing of material within the site. They recommended that caution was therefore required in literally interpreting the archaeological evidence, especially the relationship between human remains and ornaments from the Châtelperronian levels. Caron et al (2011) and Zilhão et al (2011) criticised this, citing a range of archaeological and stratigraphic evidence which suggested the opposite; that the sequence remained largely intact save for some obvious examples where the excavators had identified some material from a different layer. Hublin et al's (2012) new results have been taken to suggest that: a) the original Oxford series of determinations are largely variable due to low collagen preservation which exacerbates the contamination effect in the dated bones; b) that the selection of humanly-modified material resulted in a biased corpus of poorly preserved samples for dating; c) that the new determinations show no evidence for mixing in the site because the results are consistent with the stratigraphic divisions at the site. In this short paper we comment on these suggestions.

Abstract:

Egypt has some of the oldest written records and extended lists of named rulers. But radiocarbon dates have only fulfilled expectations 66 per cent of the time. So why haven't the two types of dating made a better match? The authors provide a dozen excellent reasons, which will sound the alarm among researchers well beyond Dynastic Egypt. © Antiquity Publications Ltd.

Abstract:

The German site of Geißenklösterle is crucial to debates concerning the European Middle to Upper Palaeolithic transition and the origins of the Aurignacian in Europe. Previous dates from the site are central to an important hypothesis, the . Kulturpumpe model, which posits that the Swabian Jura was an area where crucial behavioural developments took place and then spread to other parts of Europe. The previous chronology (critical to the model), is based mainly on radiocarbon dating, but remains poorly constrained due to the dating resolution and the variability of dates. The cause of these problems is disputed, but two principal explanations have been proposed: a) larger than expected variations in the production of atmospheric radiocarbon, and b) taphonomic influences in the site mixing the bones that were dated into different parts of the site. We reinvestigate the chronology using a new series of radiocarbon determinations obtained from the Mousterian, Aurignacian and Gravettian levels. The results strongly imply that the previous dates were affected by insufficient decontamination of the bone collagen prior to dating. Using an ultrafiltration protocol the chronometric picture becomes much clearer. Comparison of the results against other recently dated sites in other parts of Europe suggests the Early Aurignacian levels are earlier than other sites in the south of France and Italy, but not as early as recently dated sites which suggest a pre-Aurignacian dispersal of modern humans to Italy by ~45000 cal BP. They are consistent with the importance of the Danube Corridor as a key route for the movement of people and ideas. The new dates fail to refute the . Kulturpumpe model and suggest that Swabian Jura is a region that contributed significantly to the evolution of symbolic behaviour as indicated by early evidence for figurative art, music and mythical imagery. © 2012 Elsevier Ltd.