A palaeodietary investigation of carbon (C/C) and nitrogen (N/N) in human and faunal bones from the Copper Age cemeteries of Varna I and Durankulak,Bulgaria

Stable isotope analyses have been applied to human and faunal bone collagen from the Varna I and Durankulak cemeteries to explore palaeodietary adaptations in the Neolithic and Eneolithic (Copper Age). The results suggest both populations primarily utilised terrestrial, C₃-based diets, despite their proximity to the Black Sea. The wider δ¹⁵N range of the Durankulak humans likely indicates the differential utilisation of terrestrial meat sources, which is probably related to the degree to which primary and/or secondary ovicaprid products were consumed, particularly since ovicaprid δ¹⁵N values differ from other herbivores. The isotopic distribution of Varna I reflects a linear relationship between δ¹⁵N and δ¹³C, suggesting that a minority of individuals enriched in both isotopic parameters supplemented their diets with marine resources. These burials include the well known ‘chieftain’ (burial 43) and show notable material wealth by way of grave goods. At the population level, however, there is no significant correlation between stable isotope values and material wealth at Varna I, a fact with implications for theories regarding emergent social/economic hierarchies in Balkan prehistory. Five burials at Durankulak were found to have relatively enriched δ¹³C and δ¹⁵N values with respect to the rest of the population. These burials reflect a prominently marine-based or mixed terrestrial C₃-based diet that included C₄ inputs, possibly from millet, for which the limitations of stable isotope analysis on bulk collagen are not able to differentiate. AMS dating has shown that these burials belong to a much later period.     

Discovery of colon contents in a skeletonized burial: Soil sampling for dietary remains

Recovering dietary and parasitological data from skeletonized burials is often overlooked or attempted without sufficient consideration of preservation possibilities, quality sampling areas or the confounding influences of post-interment processes. A case study of a skeletonized Anasazi burial is presented to demonstrate three important points. First, that macrobotanical remains can be preserved in addition to the more durable pollen and parasite eggs. Second, that the sacrum can act as a structural container for the contents of the lower digestive tract upon decomposition of the body, thereby providing a productive sampling area. Finally, that reliable interpretation of any biological remains from skeletonized burials depends upon the analysis of several control samples. Since awareness of probable data sources plays a central role in what is actually collected and analysed, it is important to alert archaeologists to the possibilities of colon content analysis from skeletonized burials.     

Stable isotopic analysis of human and faunal remains from the Incipient Chulmun (Neolithic) shell midden site of Ando Island,Korea

We analyzed stable carbon and nitrogen isotope ratios of human and animal remains from the Ando shell midden, South Korea. The Ando site is a rare Incipient Chulmun (Neolithic) site (ca. 6000–5000 BC), which contains well-preserved human and animal bones in shell mounds. The stable isotope results for humans (average δ¹³C = −13.5 ± 0.5‰ and δ¹⁵N = 15.2 ± 0.5‰) indicate that Ando people in the Incipient Chulmun period strongly depended on marine resources. There were no isotopic differences between humans of different sex and age at this site. We compared our data with other previous published isotopic data from the Chulmun sites and found that the Ando people had similar isotope values to the southern Chulmun people (Tongsamdong and Daepo), but different isotopic ratios than the western Chulmun people (Daejukri and Konamri). These results indicate that marine foods were the main food resources in the southern coastal regions, but not in the western coastal regions in Chulmun Korea.     

Dietary shifting in the Nasca Region as inferred from the carbon- and nitrogen-isotope compositions of archaeological hair and bone

The topography of the Andean Region results in short travelling distances among ecologically distinct production zones. As such, it is possible to infer relative changes in residence based on the spatial variability in the isotopic composition of food resources. Here, we determine long-term diet through carbon- and nitrogen-isotope analysis of bone collagen for twenty-nine individuals from Cahuachi, an important ceremonial centre in the Nasca Region. We also reconstruct the temporal sequence of change in dietary isotopic compositions along hair samples for seventeen individuals buried at Cahuachi and the neighbouring site of Huaca del Loro.     

The distinction between freshwater- and terrestrial-based diets: methodological concerns and archaeological applications of sulphur stable isotope analysis

Sulphur isotopes in archaeological bone collagen are not routinely analysed in palaeodietary studies. Here we investigate the potential contribution that sulphur isotope analysis can provide toward the study of ancient human diet and economy, with particular emphasis on the distinction between freshwater and terrestrial consumers. For material from the Late Bronze Age site of Chicha in the south-western Eurasian forest-steppe, sulphur isotopes effectively separate freshwater and terrestrial animal food resources. The sulphur isotope data coupled with nitrogen isotope values from Chicha reflect a dietary reliance upon freshwater animal protein (fish) for the Late Bronze Age inhabitants. In contrast, sulphur isotope values for freshwater and terrestrial potential food species from the Eneolithic site of Bil'shivtsi in western Ukraine were indistinguishable, demonstrating that δ³⁴S values cannot always be relied upon to identify freshwater and terrestrial consumers. The data from this study support the adoption of δ³⁴S analysis as a standard component of palaeodietary studies; apart from its potential to distinguish freshwater from terrestrial consumers, it can provide supplementary dietary information not evident from the carbon and nitrogen isotope data. In addition, certain indices are considered that may be used to assess the validity of sulphur isotope data, as currently exist for carbon and nitrogen. According to the analysis of modern collagen samples, N:S appears to be a broad indicator of collagen sulphur isotope quality. However, more work needs to be done to establish an effective means by which highly-altered sulphur isotope values can be identified and thereby removed from consideration.     

Reconstructing dietary and environmental history from enamel isotopic analysis: time resolution of intra‐tooth sequential sampling

The carbon and oxygen isotopic composition of the mineral phase of tooth enamel is linked to diet and environment. Enamel is not remodelled once formed. Several studies of intra‐tooth isotopic variability in hypsodont mammal teeth have involved sequential sampling of enamel in order to detect changes in diet and environment during tooth formation. The possibility of exploring individual history opens the door to many applications, particularly in palaeoenvironment and herd management reconstruction. However, previous histological investigations have shown that enamel mineralization is a progressive and discontinuous process. The goal of the present study is to determine if this pattern significantly influences the time resolution of an intra‐tooth sequential sampling. Isotopic analyses (δ¹³C) were performed on tooth enamel from steers (Bos taurus) that had changed from a C₃ plant‐based diet to a C₄ plant‐based diet with very different carbon isotopic compositions. The change of diet was reflected in the mineral phase of enamel. The pattern of intra‐tooth isotopic variation suggests that completion of enamel mineralization required six to seven months. Such a lag in enamel mineralization will decrease the time resolution of enamel sequential sampling. The effects of prolonged mineralization of enamel have to be considered when interpreting patterns of intra‐tooth isotopic variations. Copyright © 2002 John Wiley & Sons, Ltd.     

Manuring and stable nitrogen isotope ratios in cereals and pulses: towards a new archaeobotanical approach to the inference of land use and dietary practices

This paper explores the impact of animal manure application on the δ¹⁵N values of a broad range of crops (cereals and pulses), under a range of manuring levels/regimes and at a series of locations extending from northwest Europe to the eastern Mediterranean. We included both agricultural field experiments and areas where ‘traditional’ farming is practised. Our aim is to ground-truth interpretation of δ¹⁵N values in archaeobotanical crop remains as evidence of past growing conditions and husbandry practices. The results confirm the potentially radical impact of manuring on δ¹⁵N values in cereals, depending on manuring level, but indicate only a slight effect on pulses, which can fix atmospheric nitrogen. The expected geographical trend towards greater δ¹⁵N with increasing climatic aridity is not apparent, probably because the growing conditions for crops are ‘buffered’ through crop management. Each of these observations has fundamental implications for archaeobotanical interpretation of δ¹⁵N values as evidence of land use practices and (together with analysis of bone collagen/tooth enamel in potential consumers) palaeodiet.     

An investigation of diet in early Anglo-Saxon England using carbon and nitrogen stable isotope analysis of human bone collagen

The principal aim of this work is to investigate whether protein sources in human diets in early Anglo-Saxon (5th-7th century AD) England varied with geographic location, or with respect to age or sex. The methodology used was analysis of δ¹⁵N and δ¹³C in human bone collagen from 76 adult skeletons from a total of 18 different cemeteries located in inland, riverine and coastal environments. In order to control for the possible effects of socio-economic status on diet, only high status individuals, as identified by grave goods, were studied. Data were analysed using statistical manipulation of the raw results and using IsoSource (Phillips and Gregg, 2003), a mathematical treatment which models the composition of the protein part of human diets using bone stable isotope ratios when the isotopic values for potential protein sources are known or can reasonably be inferred. The results suggest that protein sources varied little according to geographic location and that terrestrial foods dominated at all locations. However there were some subtle patterns. Slightly elevated δ¹³C in skeletons from coastal locations, and δ¹⁵N in those from riverine sites may indicate that communities in these locations made greater use of marine and freshwater resources respectively. If this is correct then it demonstrates that 5th-7th century communities made some use of wild resources even within a predominantly agrarian economy. In general the analysis of the raw data and the IsoSource results were mutually supportive, and this work demonstrates the value of this twin-pronged approach to analysis of human bone stable isotope data.     

Bromine in teeth and bone as an indicator of marine diet

Nitrogen isotope ratios in tissues are often used to aid in the reconstruction of the marine component of diets in past populations. Elevated δ¹⁵N values normally found with high trophic level marine resource consumption can, however, also be mimicked by physiological conditions (breastfeeding, pathological states affecting nitrogen balance), climate (aridity), and anthropogenic environments (manuring). This paper presents a pilot study testing whether bromine concentrations can provide a tool for teasing apart possible causes of variation in nitrogen isotope ratios. Blind analyses of bromine in archaeological samples correctly identified individuals derived from coastal vs. inland regions and high vs. low marine consumption time periods. Thus, bromine can provide an important supplement to other isotopic analyses of diet.     

Pastures lost? A dental microwear study of ovicaprine diet and management in Norse Greenland

The management of ovicaprines by the Medieval Norse farmers in Greenland is explored using dental microwear analysis. Adult and juvenile ovicaprines from Norse contexts in Greenland are shown to exhibit microwear patterns very different to those in modern Greenlandic sheep; while modern sheep demonstrate microwear consistent with low levels of soil ingestion under extensive, low stocking-rate grazing regimes, Norse sheep/goat display striated microwear patterns indicative of high levels of soil ingestion and, potentially, overgrazing. This high abrasive grazing signature is present in the inland region of the Western Settlement from 1150 AD onwards, may be evident in the inland Eastern Settlement from an equally early date and is also detected during the later phases of occupation in the Western settlement (14th and 15th centuries AD). It is argued that these results provide further evidence that maladaptive grazing practices led to a decline in the viability of pastoral farming in Greenland, and, moreover, that overgrazing did not merely occur towards the end of the settlement as a consequence of the worsening climate of the ‘Little Ice Age’ but rather was present in both the Western and the Eastern Settlement from a relatively early date.