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Rationale Embedding resins are commonly used to facilitate high-resolution sampling for stable isotope analysis but anomalous δ13C values have been observed in some cases. Here we compare the results of microsampling strategies for hand-drilled versus resin-embedded micromilled samples from the same marine shells to assess whether resin contamination is implicated in δ13C spikes. The comparison allows assessment of the relative benefits for spatial resolution, seasonal range for both δ18O and δ13C, and sample failure rates. Methods Hand-drilled samples were obtained from two bivalve shells (Spisula sachalinensis), corresponding to micromilled samples on the same shells where high δ13C spikes were observed. All carbonate powders were analysed using a dual-inlet Isoprime mass spectrometer and Multiprep device. Results from both sample sets were compared statistically. Results No anomalous high δ13C values and no failures due to insufficient gas were observed in the hand-drilled samples in contrast to the embedded micromilled sequences. Spatial resolution was reduced (~2.5×) in the former compared with the latter, resulting in a small reduction in the total range observed in the micromilled δ13C and δ18O values. Reduced sampling resolution between the two datasets was only significant for δ18O. Conclusions For S. sachalinensis (as with other similar bivalves), rapid growth mitigates the reduced sampling resolution of hand drilling and does not significantly impact observed isotopic range and seasonal patterning. Occurrence of anomalous δ13C values were eliminated and failure rates due to insufficient sample size greatly reduced in the hand-drilled dataset. We can find no other explanation for the occurrence of δ13C spikes than contamination by the embedding agent. We conclude that the logistical and interpretational benefits of careful hand drilling may be preferable to resin embedding for micromilling in marine shells, corals or speleothems where growth rate is rapid and the highest resolution is not required.

Although the Middle Stone Age (MSA) of southern Africa, associated with major cultural innovation including aspects of symbolic behavior and the development of complex hunting tools, has been the focus of intensive research, well-documented contexts for the early Middle Stone Age (EMSA) are rare. Here, we present archeological and ecological data on the EMSA occupation of Wonderwerk Cave excavated by Peter Beaumont, along with the results of luminescence dating of associated sediments to ca. 240–150 kyr, overlapping with the timing of the first known modern humans. The lithic assemblage shows a shift to prepared core flake production but lacks complex hunting equipment characteristic of the later MSA. Although ocher is present, there is no evidence of ornaments or incised objects. Multiproxy paleoclimate data from Wonderwerk Cave demonstrate that the EMSA occupation occurred under significantly wetter environmental conditions than the current semiarid regime. The Wonderwerk Cave EMSA provides strong support for the argument that critical aspects of the MSA archeological record developed long after the first appearance of modern humans.

The archaeological record shows that large pre-Inca agricultural systems supported settlements for centuries around the ravines and oases of northern Chile's hyperarid Atacama Desert. This raises questions about how such productivity was achieved and sustained, and its social implications. Using isotopic data of well-preserved ancient plant remains from Atacama sites, we show a dramatic increase in crop nitrogen isotope values (δ

Intra-tooth stable isotope analysis of dentine provides a more sensitive means to examine infant and childhood life history in the past than conventional cross-sectional analyses that rely on age-at-death. In addition, reconstructions of early diet and life history using an intra-tooth approach circumvent potential problems associated with mortality bias, which may operate strongly during infancy and childhood. We present new intra-tooth stable carbon and nitrogen isotope profiles in dentine collagen of early forming permanent teeth in a sample of adults from the Medieval Nubian site of Kulubnarti. We interpret the profiles in terms of weaning behavior and dietary history, and we compare profiles generated from first molars and canines to explore the degree to which these tooth types correspond. We then compare the profiles to the occurrence of linear enamel hypoplasia to assess the relationship between the timing of the weaning process and stress events. Finally, we compare the longitudinal profiles to cross-sectional stable isotope data obtained from rib collagen to investigate how life histories might differ between those that survived into adulthood and those that did not. Results suggest that canine and first molar profiles are in broad agreement, that hypoplastic stress events occurred during rather than before or after the weaning process in our sample, and that survivors appear to have weaned earlier than the average non-survivor. We suggest that this approach may be useful for addressing the effects of selective mortality on reconstructions of early life history and the relationship between early life history and morbidity.

Rationale Stable isotope analysis of archaeological charred plants has become a useful tool for interpreting past agricultural practices and refining ancient dietary reconstruction. Charred material that lay buried in soil for millennia, however, is susceptible to various kinds of contamination, whose impact on the grain/seed isotopic composition is poorly understood. Pre-treatment protocols have been adapted in distinct forms from radiocarbon dating, but insufficient research has been carried out on evaluating their effectiveness and necessity for stable carbon and nitrogen isotope analysis. Methods The effects of previously used pre-treatment protocols on the isotopic composition of archaeological and modern sets of samples were investigated. An archaeological sample was also artificially contaminated with carbonates, nitrates and humic acid and subjected to treatment aimed at removing the introduced contamination. The presence and removal of the contamination were investigated using Fourier transform infrared spectroscopy (FTIR) and δ13C and δ15N values. Results The results show a ca 1‰ decrease in the δ15N values of archaeological charred plant material caused by harsh acid treatments and ultra-sonication. This change is interpreted as being caused by mechanical distortion of the grains/seeds rather than by the removal of contamination. Furthermore, specific infrared peaks have been identified that can be used to detect the three types of contaminants studied. We argue that it is not necessary to try to remove humic acid contamination for stable isotope analysis. The advantages and disadvantages of crushing the grains/seeds before pre-treatment are discussed. Conclusions We recommend the use of an acid-only procedure (0.5 M HCl for 30 min at 80°C followed by three rinses in distilled water) for cleaning charred plant remains. This study fills an important gap in plant stable isotope research that will enable future researchers to evaluate potential sources of isotopic change and pre-treat their samples with methods that have been demonstrated to be effective. © 2014 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.

High resolution incremental isotopic analysis of the dentine from early forming teeth, especially first molars (M1s), provides a means to assess the effects of poor childhood nutrition and healthcare on individuals in an assemblage where there are no infants to study. This approach is applied to an 18th and 19th century cemetery population associated with St Saviour's Almshouse burial ground in Southwark, London, to assess whether, or how, early dietary history, including weaning age, influenced health and nutritional status. The results show a general pattern in which non-breast milk foods were introduced before or by 6 months of age, as indicated by elevated δ(15) N during this period. Almost all individuals for which we also have second molar (M2) records, showed lower δ(15) N values from a very young age (1 year) until approximately 8-10 years, compared to adult values. The overall results show a significant difference in δ(1) (3) C (p = 0 to 4sf, F = 17.327) and a weaker statistical difference in δ(15) N between males and females (p = 0.019, F = 5.581). One possible cause of this is a difference in the diet of males and females early in life, or alternatively, a greater susceptibility of males to nutritional deprivation compared to females. The latter argument is strengthened by a significant difference in the incidence of enamel hypoplasia between the males and females, with 7.7% of male teeth showing defects, compared to 3.9% of females.

The activities of hunter-gatherers are often captured in rockshelters, but here the authors present a study of a riverside settlement outside one, with a rich sequence from 1300 BC to AD 800. Thanks to frequent flooding, periods of occupation were sealed and could be examined in situ. The phytolith and faunal record, especially fish, chronicle changing climate and patterns of subsistence, emphasising that the story here is no predictable one-way journey from hunter-gatherer to farmer. Right up to the period of the famous nineteenth-century rock paintings in the surrounding Maloti-Drakensberg region, adaptation was dynamic and historically contingent.

Cremated bone occurs in many archaeological sites as small grey and white fragments. The high temperatures reached during heating induce structural, elemental and isotopic changes to bone apatite (the inorganic fraction of bone). These changes are investigated here by infrared spectroscopy and mass spectrometry (δ13Cap, δ18Oc, δ18Op and 87Sr/86Sr) in both modern heated bone and archaeological cremated specimens. The results of various heating experiments (in laboratory and natural conditions) highlight the significant carbon and oxygen exchanges with the fuel used as well as with bone organic matter (mainly collagen). While not informing on dietary practice and hydrology as is the case with unburned bone/tooth, the carbon and oxygen isotope ratios of calcined samples together with infrared spectroscopy results provide information on the conditions in which the bone was burned (e.g. presence of fuel, size of the pyre, temperatures reached, dry or fresh bone, etc.). In contrast, the effect of burning on the strontium present in bone is minimal. Furthermore, as observed through artificial contamination experiments, post-burial alterations also appear to be extremely limited, which is to be expected due to the higher crystallinity of calcined bone apatite compared to unburned bone and even enamel. These experiments demonstrate that calcined bone provides a reliable substrate for mobility studies using its strontium isotope composition. The results of this work greatly extend the application of strontium isotopes to places and periods in which cremation was the dominant mortuary practice, or where unburned bone and enamel do not survive. Furthermore, carbon and oxygen isotope analyses and infrared spectroscopy provide insights into the reconstruction of ancient cremation practices.

Due to the very high temperatures reached during cremation (up to 1000ºC and more) it has generally been assumed that the traditional stable isotope methods used on unburned bone are not applicable to cremated bone. However, various studies have shown that cremated bone provides a reliable substrate for radiocarbon dating and strontium isotope analyses. This poster presents the results of on-going research on the carbon, oxygen and strontium isotope ratios of calcined bone (δ13Cap, δ18Oc, δ18Op, 87Sr/86Sr), REEs, infrared and µXRF analyses. By looking into these different parameters it is possible study landscape use and mobility patterns at sites where cremation was practiced. It also allows investigating changes from marine to terrestrial diets as well as cremation practices. These new developments have been successfully applied to archaeological sites from Mesolithic, Neolithic and Bronze Age Ireland and UK. This poster presents and compares the results from these different sites and discusses their implications and future research.