Organic residues preserved on the outer surfaces of archaeological pottery are commonly considered to be soot and, not being subject to reservoir effects, as more reliable for radiocarbon (14C) dating compared to food crusts from the inner surface. However, unlike food crusts, outer surface residues are never analyzed prior to 14C dating. This study confronts 14C dates on inner and outer surface residues preserved on prehistoric pottery from Bazel Sluis (Belgium) with the results of stable isotope analysis and thermally assisted hydrolysis and methylation pyrolysis-gas chromatography-mass spectrometry (THM-GC-MS). These analyses clearly show that food residue is also present on the outer pottery surface, causing a possible reservoir effect on 14C dates. At Bazel, 14C dates on both the inner and outer surface residues are too old compared to dates obtained on associated animal bone. In addition, the outer surface residues systematically date younger than the inner food crusts, a discrepancy that is also known from other archaeological sites. It is suggested that these age differences are due to the mixed presence of soot and food residue on the exterior vessel wall as opposed to more homogeneous food crusts on the internal surface.

The ancient Egyptians mummified animals as part of cultic activity from the Late Period into the Roman era (7th century BC to the 4th century AD). Necropolises have provided millions of animal mummies, reflecting the religious fervor of Egyptians with regard to sacred animal cults during this period. Despite the number of sites containing mummies, and the number of mummies themselves, surprisingly little is known with regard to the nuances in the dating of the cults’ popularity and activities. As part of a multidisciplinary project, we have conducted a series of radiocarbon dates based on a group of animal mummies from the collection of the Musée des Confluences in Lyon, France. Thus, 63 specimens of animal mummies and their wrappings were analyzed to provide a range of dates for this practice. Results show that some correlations can be made between the popularity of particular species and the time period in which they were mummified. Monkeys and goats appear to have been among the first mummified species (from 800 BC), while antelopes appear to be a later addition to the corpus (30 BC to 4th century AD), thereby reflecting changes in thought processes, religious beliefs, and economic imperatives over time.

As part of a multidisciplinary project concerning the practices of mummification in ancient Egypt, we studied a series of 33 human remains, collected during the late 19th century. These heads of human mummies belong to the Osteology collection from the Musée des Confluences of Lyon. One of the important issues of this research project was to establish a chronology of the mummification processes. However, the lack of archaeological data and excavation reports does not allow the dating of the specimens. Thus, during this project, these heads have been radiocarbon dated in order to place the individuals in a reliable chronological and cultural framework. As a result, 20 samples of hair and 13 samples of linen textiles of the wrappings have been taken. The results raised a lot of uncertainties about the chronology of these mummies and the need to validate or correct the original date attributions were given by the discoverers. As an example, among the 13 mummies thought to be dated between the 11th and 20th Dynasties, none appears from this period. In the same way, six mummies were originally dated from the Ptolemaic period. However, only one belongs to this period, four are Roman, and the last one is from the New Kingdom.

A regional offset (ΔR) from the marine radiocarbon calibration curve is widely used in calibration software (e.g. CALIB, OxCal) but often is not calculated correctly. While relatively straightforward for known-age samples, such as mollusks from museum collections or annually banded corals, it is more difficult to calculate ΔR and the uncertainty in ΔR for 14C dates on paired marine and terrestrial samples. Previous researchers have often utilized classical intercept methods that do not account for the full calibrated probability distribution function (pdf). Recently, Soulet (2015) provided R code for calculating reservoir ages using the pdfs, but did not address ΔR and the uncertainty in ΔR. We have developed an online application for performing these calculations for known-age, paired marine and terrestrial 14C dates and U-Th dated corals. This article briefly discusses methods that have been used for calculating ΔR and the uncertainty and describes the online program deltar, which is available free of charge.

The Grotte Cosquer (southeastern France) is a Paleolithic painted cave only accessible by a deep-water dive. The cave has yielded numerous Paleolithic engravings and drawings, which were produced from wood charcoal. This article presents new radiocarbon dates obtained on samples collected in 2012 directly on 17 parietal representations and at the soil surface, and discusses the 14C results obtained since the discovery of the cave in 1992. A total of 41 samples were dated with ages ranging from 33,000 to 20,000 cal BP. They show that the cave was intermittently decorated over about 10,000 yr.

This paper describes the results of Bayesian modeling of radiocarbon dates from Early Bronze Age contexts in Southern Mesopotamia, modern-day southern Iraq. The model uses 14C dates available in the literature, employing archaeological and textual information to correlate contexts from a number of important Mesopotamian sites. The insufficient number of dates makes it impossible to precisely define the chronology of the period in question; however, the analysis allows for observing patterns of cultural change otherwise invisible in archaeological and textual records. Firstly, it is suggested that there was a hiatus of at least a century between the latest protocuneiform texts and the earliest historical writing. Furthermore, the results seem to argue against a steady, gradual evolution of literate civilizations, indicating a more complex and varied process of development.

This study aims at comparing the reliability of different types of apatite fractions for which collagen cannot be dated. We focused on the remains of individuals found at the necropolis of Porta Nocera near Pompeii, and for which the date of burial can be assessed independently. The dated human samples range between 1805±49 and 5570±120 14C yr BP and can display a large (up to 1200 14C yr) intra-individual age variability. We show that while a marine diet or an old-wood effect could explain the smallest age shifts, they are not able to explain the largest ones, and propose diagenesis as the main cause. The 14C depletion is likely due to the influence of the 14C-free CO2 emissions of the nearby Vesuvius volcano and the Campi Flegrei volcanic system on the age of secondary carbonate incorporated into the bone and enamel crystallites during diagenesis. This study demonstrates that in volcanic contexts, a large deviation from expected age can be measured, even in calcined apatites. Our calculations indicate that while the absolute amount of contamination is lower in calcined bones than in burnt bone and enamel apatite, its impact on the 14C age of the sample can be much higher due to the low carbon content of calcined bones.