Carbon Isotope Variability in the Bone Collagen of Red Kangaroos (Macropus rufus) is Age Dependent: Implications for Palaeodietary Studies

Isotopic assessment of bone collagen is often used as an environmental tracer in both contemporary and palaeoenvironmental studies. However, variability in the isotopic composition of this tissue remains poorly understood for naturally occurring and wild populations of animals. In this study the stable carbon isotope composition of both diet and bone collagen was assessed for a population of red kangaroos (Macropus rufus). Animals sampled ranged in age from approximately 10 months to 15 years. The diet of this population, estimated from faeces collected in the field, varied from predominantly C₄grasses in late summer (δ¹³C⋍−16·5‰) to mostly C₃herbage in late winter (δ¹³C⋍−22·5‰), with a long-term average δ¹³C of between −19 and −20‰. Bone collagen was enriched in¹³C by 3 to 4‰ in older animals relative to pouch young. Isotopic analysis of hair, used to assess more recent diet in individuals, indicated that diet selection was similar in all animals that had been weaned. We suggest that the most likely explanation for the age-dependent relationship in the δ¹³C of bone collagen occurs because milk (the only source of nutrition in suckling kangaroos) is not fractionated in the same manner as plant-derived carbon during its assimilation into skeletal tissue. If this is the case, then such a relationship should be most predominant in mammals that have low birth weights (relative to the adult mother) and gain significant weight from milk. Whatever the precise mechanism(s) for the observed fractionation, bone collagen of kangaroos seems to retain an isotopic memory of the carbon laid down prior to weaning, which takes several years to be diluted and replaced with carbon derived from an “adult” herbaceous diet. These results have implications for palaeoecological research where fossil skeletal tissue is used as dietary or environmental tracers particularly if the relative age of the animals sampled is unknown.     

Let them eat cake? Status-based differences in diet in medieval Denmark

The goal of this research is to explore status-based differences in diet of the peasants, monks and elites interred at the medieval Cistercian monastery of Øm Kloster. In order to accomplish this task bone samples were taken from 98 individuals from the monastery for the stable isotopic analysis of carbon and nitrogen found in both bone collagen and apatite. Significant differences were found in the diet of these three groups. Elites demonstrated significantly enriched δ¹⁵N and δ¹³C values and had the smallest δ¹³C_coll-ap spacing in comparison to the peasant and monastic population. Although there were no changes in the diet of the elite or peasant population through time, the monastic diet shifted from resembling the diet of the peasant population early in the period to more closely matching that of the elites at the close of the period, although small sample size precluded the significance testing of this shift. This research suggests that social status played a considerable role in the types and quantity of food resources available to a given individual in society and that there were some socially based differences in the medieval Danish diet.     

Chicken and Egg: Testing the Carbon Isotopic Effects of Carnivory and Herbivory

In bone, the spacing between δ¹³C in collagen and bioapatite carbonate is greater in herbivores than carnivores, with implications for understanding animal dietary ecology from surviving hard tissues. Two explanations have been proposed: varying diet composition or differences in physiology between herbivores and carnivores. We measured the isotopic effects of carnivorous and herbivorous diets on a single species, to test the effect of diet composition alone. Protein δ¹³C and δ¹⁵N and carbonate δ¹³C were measured on egg and bone from hens on different diets. Herbivorous hens had a +14.3‰ spacing between egg albumen and shell δ¹³C, compared to +12.4‰ for omnivorous hens, and +11.5‰ for carnivorous hens. The bioapatite–collagen Δ¹³C spacing was measured as +6.2‰ for herbivorous hens, and calculated as +4.3‰ for omnivorous hens, and +3.4‰ for carnivorous hens—similar to observed mammalian herbivore and carnivore bioapatite–collagen Δ¹³C differences. We conclude that a shift in diet composition from herbivory to carnivory in a single species does alter the bioapatite–collagen carbon isotopic spacing. Our data strongly suggest that this results from differences in the Δ¹³C_{bioapatite–diet} spacing, and not that of Δ¹³C_{collagen–diet}.     

Preliminary evidence for medieval Polish diet from carbon and nitrogen stable isotopes

In this pilot study, stable carbon and nitrogen isotopes from bone collagen and apatite of skeletons from the 11th and 12th century cemetery in Giecz, Poland are interpreted. Isotope values from a small number of fish and animal bones from the same archaeological site are also examined. The goal of this research is to provide preliminary evidence of diet for a group of medieval Polish peasants, with particular emphasis on sex-based differences in diet. Results of isotope analyses suggest diet of this early medieval population was omnivorous and terrestrial-based. Fish bones sampled exhibit low δ¹³C ratios, and in half of the cases are significantly enriched in ¹⁵N, indicating they are freshwater species. Human bones do not reflect these signatures, suggesting freshwater fish were not a significant source of dietary protein at Giecz. The ¹³C_coll from some human bones is enriched beyond what might be expected from an exclusively C₃ diet. Associated mammal bones do not exhibit similarly elevated δ¹³C_coll ratios, suggesting enrichment among humans is not due to consumption of animals foddered on C₄ plants. Two possible sources of ¹³C_coll enrichment are marine fish in diet and direct consumption of a C₄ plant, such as millet. The δ¹³C values obtained from bone apatite of a small subset of humans suggest that millet contributes to ¹³C_coll enrichment, although at least three individuals may have also consumed small amounts of marine fish. Sex-based differences in δ¹⁵N ratios indicate that men consumed relatively more animal products (meat or dairy) than did women. There is also a correlation between δ¹³C_coll and δ¹⁵N values in skeletons of men that is absent in women. These carbon and nitrogen isotope data are the first reported for any Polish population and contribute to a more complete picture of dietary adaptation and social organization in medieval Europe.     

Age‐related variation in isotopic indicators of diet at medieval Kulubnarti,Sudanese Nubia

This study compares trends in dietary composition in two large cemetery populations from the site of Kulubnarti (AD 550–800) in Sudanese Nubia. Bone collagen and bone apatite carbonate were analysed to characterise stable carbon, nitrogen and oxygen isotopes. Previous research on these cemeteries has suggested marked differences in nutritional status and health between the populations. Contrary to expectations, there were no significant relationships between any isotopic indicators related to sex or cemetery of burial, suggesting no isotopically‐measurable differences in diet. However, collagen δ¹³C and δ¹⁵N were significantly related to age, suggesting age‐related differences in protein intake or other factors. Weaning trends are gradual and variable, with the range in δ¹⁵N values exceeding 4‰ among infants/young children (0–3 yrs) and standard deviations exceeding 1‰ in collagen δ¹³C and δ¹⁵N for both infants/young children and subadults (4–17 yrs). This suggests varied weaning strategies among both populations and variable diets prior to adulthood. Also observed was a distinct range of isotopic carbon and nitrogen values among individuals classified as subadults (4–17 yrs), who are depleted in collagen δ¹³C and δ¹⁵N relative to adults. However, both infants/young children and subadults are slightly enriched in δ¹⁸O relative to adults, which suggests the presence of non‐local individuals or age‐related variation in water sources. While most isotopic studies of age‐related dietary trends have focused on reconstructing the weaning process, this study presents findings that indicate tripartite isotopic trends distinguishing infancy, subadulthood and adulthood as separate dietary categories. Broad similarities are evident between the results presented here and those from several earlier studies of smaller populations and to nutritional studies of modern communities. These findings suggest that further research into health disparities at Kulubnarti should focus on non‐dietary causal factors, and more generally, that greater attention should be paid to subadulthood in palaeodiet studies. Copyright © 2006 John Wiley & Sons, Ltd.     

Isotopic Comparison of Hair,Nail and Bone: Modern Analyses

This paper presents a comprison of the isotopic values of eight pairings of hair keratin and bone collagen and 12 pairings of hair keratin and nail keratin taken from living humans resident in the U.K., with the aim of examining whether modern human isotopic data can be directly compared to archaeological isotopic data.Results showed that bone collagen was enriched relative to hair keratin from the same individual by +1·4‰ in δ¹³C and +0·86‰ in δ¹⁵N, with some small degree of variability. Isotopic comparison of hair keratin and nail keratin from the same individual showed that there is no significant difference between hair and nail keratin in δ¹³C, but that nail keratin is on average +0·65‰ more enriched in δ¹⁵N than hair.Differences in amino acid composition between hair keratin and bone collagen may account for the carbon isotopic differences between the two proteins, and there is no significant overall carbon isotopic difference between hair and nail. However there are significant isotopic differences for nitrogen in the two pairings, that differences in amino acid composition and turnover times cannot explain. We suggest that these results indicate that constancy of isotopic values between tissues, even for similar proteins, cannot be taken for granted.     

Stable isotopic analysis of human bones from Jiahu site,Henan, China: implications for the transition to agriculture

We have investigated change in subsistence during the transition to agriculture in the site of Jiahu, Henan Province, China, using stable isotopic analysis of collagen and apatite in human bones. Millet agriculture is well documented at drier high latitudes of the Yellow River Valley, while rice agriculture predominated at wetter lower latitudes of the Yangtze Valley region. The early Neolithic site of Jiahu lies near the boundary between the drier north and wetter south. Archaeobotanical evidence shows that rice was a significant component of diet at Jiahu, but its δ¹³C value is similar to that of other foods, and therefore cannot be conclusively identified by carbon isotope analysis. Foxtail and broomcorn millets are the only C₄ crops known for the Chinese Neolithic. Because of their high δ¹³C values, their consumption can be evaluated by stable carbon isotope analysis of human bone. Collagen reflects mainly the δ¹³C value of dietary protein, and apatite accurately records that of the whole diet. Isotopic analysis of 15 well-preserved samples from three periods shows that collagen δ¹³C values were very low for almost all individuals, suggesting C₃-based foods dominated their diets. However, apatite carbonate δ¹³C values and δ¹³C spacing between collagen and apatite (Δ¹³C_ap-co) indicate that millet may have been a minor component of the diet in this region. Individuals, who consumed the smallest amounts of animal protein, as indicated by low δ¹⁵N, generally had the highest apatite δ¹³C values. Archaeobotanical evidence for millet at Jiahu is needed to support this interpretation.     

The effect of parity status on δN: looking for the “pregnancy effect” in 18th and 19th century London

This study examined the effect of parity status on δ¹⁵N using the well-characterised 18th and 19th century skeletal collection from the crypt of Christ Church, Spitalfields, London. We tested whether the cumulative effect of multiple pregnancies and breastfeeding could significantly reduce female δ¹⁵N values compared to males. The results from stable isotope analysis of 92 adult ribs show that the population of Spitalfields had relatively little variation in diet, compared to contemporary urban populations, and had abundant animal and marine protein. We were able to rule out any effect attributable to socio-economic status, date or age at death on the stable isotope ratios. There were no significant differences in δ¹⁵N due to parity status, nor were there any differences between males and females. Models of collagen turnover rates in ribs suggest that the effect of δ¹⁵N depletion due to pregnancy would be undetectable except in ideal circumstances, where bone of the optimal turnover period was sampled, and in cases where multi-parous individuals died shortly after parturition.     

STABLE CARBON ISOTOPE MEASUREMENTS OF THE CARBOXYL CARBONS IN BONE COLLAGEN*

In order to explore the possibility that intramolecular differences in the δ¹³C value of bone collagen can provide useful infomation for isotopic dietary analysis, a method for reliably measuring the δ¹³C value of the peptide-bonded carboxyl carbons in collagen was developed and applied to a wide range of modem and ancient species, including humans. Carboxyl carbons were selectively removed as CO₂ by decarboxylation of collagen hydrolysates with ninhydrin (2,2-dihydroxy-l,3-indanedione). Carboxyl carbons were usually isotopically heavier than the total carbon in the collagen, with differences ranging from -0.9 to 4.0%c. Animals at higher trophic levels and with more positive δ¹⁵N values usually had smaller differences than the lower animals while humans had the largest range, reflecting their larger range of diets.     

Distinguishing sheep and goats using dental morphology and stable carbon isotopes in C4 grassland environments

Distinguishing between sheep and goats in C₄ grass environments using new dental morphology criteria and enamel bioapatite stable carbon isotope ratios (δ¹³C) was tested on 35 modern individuals from the Central Rift Valley of Kenya. Two morphological criteria on the second and third lower molars, one of which had been previously partially described by Halstead et al. [Journal of Archaeological Science 29 (2002) 545], were found to be highly reliable in this population. Identification of species using carbon isotope ratios is made possible in some circumstances by differences in the feeding behavior of sheep, which are mainly grazers, and goats, which are mainly browsers. In environments where C₄ grasses predominate, sheep include a higher proportion of C₄ plants in their diet, and thus have higher δ¹³C values than goats. In the present study, the annual range and seasonal variation of carbon isotope ratio of diet of sheep and goats was measured from intra-tooth sequential analysis. Although the ranges of goat and sheep δ¹³C values overlap, those higher than −3.4‰ all belong to sheep; values lower than −5.2‰ all belong to goats. There is no overlap of the mean δ¹³C values by tooth, which range from −11.8‰ to −4.2‰ for goats, and from −3.1‰ to −1.3‰ for sheep. These results suggest that carbon isotope analysis of bone collagen and/or apatite will also distinguish sheep from goats in tropical C₄ grasslands. Application of the δ¹³C criteria to archaeological material must be restricted to C₄-dominated environments, and where potential access to C₃ plants (mobility, foddering) can be assessed. The utility of these morphological and isotopic criteria for differentiating sheep and goat breeds in other regions remains to be evaluated.     

Isotopic palaeodiet studies of Ancient Egyptian fauna and humans

We report here stable carbon and nitrogen isotope results from human and faunal bone collagen from samples taken from sites in the Egyptian Nile Valley and surrounding region, dating from the Predynastic (c. 5500 BC) through to the Dynastic (c. 343 BC) periods. Isotopic values for the human population cluster together across this broad time range, with high δ¹⁵N ratios, and δ¹³C values indicating a largely C₃ based diet. The human data is not easily explained through comparison with our associated faunal data, and so may be explained by the consumption of protein from an ecosystem we did not adequately sample, such as freshwater fish or plants and fauna with unusually high δ¹⁵N values due to the extreme aridity of this region. The faunal isotopic data we did produce shows a great range in values between and within species, especially in cattle, and reflects the close proximity of three ecozones across a relatively narrow geographical area; the river, the immediate flood-plain area around the Nile and the desert surroundings.     

FOCUS: effect of diet and protein source on carbon stable isotope ratios in collagen: follow up to

We analyzed carbon stable isotope data from bone collagen of animals consuming varied experimental diets, including recently published data from Warinner and Tuross [Warinner, C., Tuross, N., 2009. Alkaline cooking and stable isotope tissue–diet spacing in swine: archaeological implications. Journal of Archaeological Science 36, 1690–1697; this journal]. Comparing regression lines for the relationship between collagen and diet δ¹³C, we show that protein source, and not physiology, explains the apparent taxonomic difference between swine and rodents reported in that paper. Our results reveal a complex relationship between whole diet and dietary protein in determining collagen δ¹³C values, such that in many cases, collagen alone may not provide reliable reconstructions of paleodiet. We advocate the simultaneous use of both collagen and apatite δ¹³C, whenever possible, to assess the diets of prehistoric peoples.     

Stable isotopes and human diet in central western Argentina

Central western Argentina is the southern boundary of prehispanic maize in the archaeological record. This paper explores the stable isotope information from human bone (δ¹³C, from collagen and δ¹³C from apatite) and tooth (δ¹³C from enamel) samples in order to characterize the temporal and spatial trends of these isotopes and to understand them in terms of human diet. We analyzed 104 human individuals from the last 6000 years. Using the Kellner and Schoeninger (2007) model the results shows a high variation in human diet with few human individuals with a notably high significance of C₄ plants (probably maize) as an energy source and these samples have a chronology around ca. 1000 years BP. On the other hand a high variation in an individual’s dietary life history is shown by differences between δ¹³C collagen, apatite and enamel.     

Reconstructing Life Histories Using Multi‐Tissue Isotope Analysis of Commingled Remains from St Stephen's Monastery in Jerusalem: Limitations and Potential

The examination of isotope ratios from multiple tissues offers new life to interpretations of commingled assemblages where information regarding individual biological history has been lost. Here, life histories from a commingled sample of Byzantine monks were reconstructed using enamel and bone δ¹³C and δ¹⁵N values. The δ¹³C values suggest a diet dominated by C₃ products, while the δ¹⁵N ratios indicate variable contributions of animal protein. After correcting for tissue‐specific enrichment factors, bone δ¹³C values were significantly enriched over enamel; this may be due to an increase in protein consumption, but could also reflect structural differences between tissues or correction factors used to compare these data.     

IN VITRO DECOMPOSITION OF BONE COLLAGEN BY SOIL BACTERIA: THE IMPLICATIONS FOR STABLE ISOTOPE ANALYSIS IN ARCHAEOMETRY*

To understand biogenic collagen type I decomposition and to establish how diagenesis may bias archaeometric data, modern mammalian bone was inoculated with a selection of ubiquitous soil bacteria. The presence of exogenous microbial biomass in the inoculated specimens was then checked microscopically prior to collagen extraction. The experimentally degraded bone collagen showed altered amino acid compositions, attributable to the selective breakdown of certain amino acids by the bacteria. While both the bulk collagen extract and the single amino acids exhibited shifts to more negative δ¹³ C-values, enrichment was recorded for general δ¹³ N, and a depletion trend relative to unaltered collagen was observed for individual amino acid δ¹³ N. One explanation for the enrichment of the global δ¹⁵N-values is cleavage of peptide bonds, which leaves ¹⁵ N within the substrate, while the change of ¹³C is mostly due to the altered amino acid composition. On the other hand, possible repolymerization of cleavage products under experimental conditions may also be responsible for the depletion trend of individual amino acid δ¹³C- and δ¹⁵ N-values. This paper discusses the results as a basis for the development of a method for the reconstruction of the isotopic abundance of the original collagen, using the amino acid composition of the degraded product, the contribution of individual amino acids to its global δ-values and of isotope discriminations implied in the microbial decomposition.     

Stable Carbon and Oxygen Isotope Spacing Between Bone and Tooth Collagen and Hydroxyapatite in Human Archaeological Remains

Spacing between stable isotope values in bones and teeth is a valuable tool for examining dietary influences and diagenesis. This study examines carbon and oxygen isotope values from collagen and hydroxyapatite (structural carbonate and phosphate) in archaeological human bones and teeth to derive species‐specific correlation equations and isotope spacing values. The δ¹³C_collagen and δ¹³C_{structural carbonate} in bone and dentin collagen show a strong correlation (R = 0.87, 0.90, respectively) with an average Δ¹³C_carb‐coll spacing of 5.4‰. The consistency of this isotope spacing with other large mammals and in humans with both low and high protein intake (as indicated by enriched δ¹⁵N values) suggests a similar allocation of protein‐derived carbon and whole diet‐derived carbon to collagen and structural carbonates, respectively, as other terrestrial mammals regardless of absolute meat intake. The δ¹⁸O_{structural carbonate} and δ¹⁸O_phosphate show the strongest correlation in enamel (R = 0.65), weaker correlations in dentin (R = 0.59) and bone (R = 0.35), with an average Δ¹⁸O_carb‐phos of 7.8‰. This isotope spacing is slightly lower than previously reported for large mammals and limited available data for humans. The results potentially indicate species‐specific fractionations and differing access to body water and blood‐dissolved inorganic carbonates in the presence of collagen formation. The use of correlation between δ¹⁸O_{structural carbonate} and δ¹⁸O_phosphate to determine diagenetic state is not recommended. The strength of this correlation observed in bones and teeth is variable and alternate indicators of diagenetic state (i.e. C:N ratios of collagen) provide more robust and independent evidence of isotope preservation despite presence/absence of a strong isotope correlation. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.     

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.     

Paleonutritional and paleodietary survey on prehistoric humans from Las Cañadas del Teide (Tenerife,Canary Islands) based on chemical and histological analysis of bone

The aim of the present study is to perform a paleodietary and paleonutritional survey on 17 individuals buried in accordance with the prehispanic ritual in the central plateau of the island Tenerife, called Las Cañadas del Teide. We recorded hydrogen, nitrogen and carbon isotope compositions of human bone collagen, bone barium and strontium, and histomorphometrically assessed trabecular bone mass (TBM). Bone trace elements and TBM were compared with reference data derived from a modern sample consisting of 13 individuals. In addition, δ¹⁵N and δ¹³C values were determined in several modern indigenous plants, bone collagen of prehistoric domestic animals (goat and pig), and prehistoric wild animals (a giant lizard, Gallotia goliath and a giant rat, Canaryomis bravoi), which represent food sources potentially consumed by the prehistoric population of the Island. The carbon stable isotope composition of bone collagen ranged between ?20.5 and ?18.6‰ (VPDB), indicating a diet based on C₃ plants. Nitrogen isotope values ranged from 8.2 to 12.4‰ (AIR), suggesting a general meat-enriched diet, most likely domestic goats, of higher level consumers. Hydrogen isotope values ranged from ?18 to +4‰, whereas log Ba/Sr was greater than ?0.40 in the vast majority of cases. TBM showed a tendency to osteoporosis in 30% of the individuals analyzed. C-14 dating showed that two burial sites, including 5 individuals, belonged to the post-conquest era (after the 15th century), despite a fully “prehispanic” burial ritual, which lends credenceto the oral tradition that some of the prehispanic population fled to the highlands at the time of the Spanish conquest, and lived there during decades or even centuries. These individuals showed lower δD, δ¹³C and δ¹⁵N, and higher log Ba/Sr values than those buried before the Spanish conquest, suggesting dietary differences between the two groups. Also, women showed a trend to a higher consumption of vegetables than men.     

Reconstructing Diet of the Early Qin (ca. 700–400 BC) at Xishan,Gansu Province,China

Here we report the bone collagen carbon and nitrogen isotopic results of humans (n = 33) and animals (n = 58) to reconstruct the dietary practices of an early Qin population dating to the Zhou Dynasty (Late Western–Early Eastern period ca. 700–400 BC ) at the Xishan site in Gansu Province, China. The humans have a very large range of δ¹³C (−23.3‰ to −7.1‰) and δ¹⁵N (4.3‰ to 10.9‰) values which reflects extraordinarily diverse diets and included individuals with predominately C₃ as well as those with exclusive C₄ diets. This wide span of isotopic results produced a subtle linear trend (R² = 0.62) in the human data, which paralleled the animals across the C₃ and C₄ environmental gradient. However, the majority of the individuals had a predominately C₄ diet based on millet with δ¹⁵N results only slightly elevated above the animals, except for the pigs and cattle. This is evidence that many of the animals were likely used for their secondary products, labour or as sacrificial offerings and that pork and beef were the main sources of animal protein for the population. High status individuals had elevated δ¹⁵N values (10.2 ± 0.6‰) compared to medium (8.9 ± 0.3‰) and lower status (8.8 ± 0.8‰) individuals, possibly related to increased animal protein in the diet. Differences related to gender were also found with females having elevated δ¹³C (−11.2 ± 1.9‰) and δ¹⁵N (9.4 ± 0.8‰) values compared to the males (δ¹³C = −14.1 ± 4.2‰; δ¹⁵N = 7.9 ± 1.9‰), but these results necessitate caution given the large number of individuals that could not be sexed. The results of this study support the view that the early Qin people were a more sedentary society focused on millet agriculture and animal husbandry, and that they were influenced by the pre‐existing populations of the central Gansu region. Copyright © 2015 John Wiley & Sons, Ltd.     

Strontium and stable isotope evidence for diet and mobility in Roman Gloucester,UK

This paper presents the results of a multi-isotopic (oxygen, strontium, carbon and nitrogen isotopes) investigation of population and dietary diversity in Roman Gloucester, focusing on individuals found in a late 2nd century AD mass burial pit at London Road, and comparing them to those found in the nearby cemetery. There were no statistical differences in isotopic composition between mass grave and cemetery burials, suggesting, in agreement with the osteological evidence, that the mass burial was the result of a catastrophic event, probably an epidemic disease. Strontium and oxygen isotope analysis demonstrated considerable diversity in the origins of the Gloucester population, with evidence for both UK and non-UK individuals. Diet was predominately terrestrial and similar to that of other Romano-British populations. Elevated δ¹³C_dentine ratios in some individuals are correlated with raised δ¹⁸O_p values and are therefore probably due to childhoods spent in warmer climates, rather than dietary variation.