Prof Christopher Ramsey

Abstract:

Higham et al (2010) published a large series of new dates from the key French Palaeolithic site of the Grotte du Renne at Arcy-sur-Cure. The site is important because it is one of only two sites in Europe in which Châtelperronian lithic remains co-occur with Neanderthal human remains. A large series of dates from the Mousterian, Châtelperronian, Aurignacian and Gravettian levels of the site was obtained. The 14C results showed great variability, which Higham et al (2010) interpreted as most likely to be due to mixing of archaeological material in the site. In contrast, Caron et al (2011) suggested that the site stratigraphy is well preserved and that the problem with the variability in the radiocarbon ages was due to unremoved contamination in the dated bone. In this paper we address their critique of the original Higham et al (2010) paper.

Abstract:

Peat is notoriously difficult to radiocarbon date as it is composed of a heterogeneous mix of organic materials of different radiocarbon ages and at different stages of humification. Different chemical fractions (most frequently humin and humic acid) have been observed to yield significantly different radiocarbon ages from some peat deposits. Here we present humin and humic acid dates on a range of grain-size fractions of peat from the open-air archaeological site of Ahrenshöft LA 58 D, northern Germany, which were measured to confirm the identity of the source of cryptotephra found at the site. Both the humin and humic acid ages increased with increasing grain size, and for all but one sample the humic acid fraction was younger than the corresponding humin date. When calibrated the 6 dates from the horizon containing the cryptotephra spanned a time period of up to 1500 years, and are insufficiently conclusive to definitively resolve which eruption is responsible for the observed ash horizon. © 2011 Elsevier B.V.