Radiocarbon reservoir effects in human bone collagen from northern Iceland

Human bone collagen from a series of Icelandic human pagan graves was radiocarbon (¹⁴C) dated to aid understanding of early settlement (landnám) chronologies in northern Iceland. These individuals potentially consumed marine protein. The ¹⁴C age of samples containing marine carbon requires a correction for the marine ¹⁴C reservoir effect. The proportion of non-terrestrial sample carbon was quantified via measurement of carbon stable isotopes (δ¹³C) using a simple mixing model, based on δ¹³C measurements of archaeofaunal samples. Non-terrestrial carbon was also quantified in six pig bones from the archaeofaunal dataset. Assuming all non-terrestrial carbon in human and pig bone collagen was marine-derived, calibrated age ranges calculated using a mixed IntCal09/Marine09 calibration curve were consistent with an early settlement date close to landnám, but several samples returned pre-landnám age ranges. Measurements of nitrogen stable isotopes (δ¹⁵N) strongly suggest that many of the human bone collagen samples contain freshwater diet-derived carbon. Icelandic freshwater systems frequently display large freshwater ¹⁴C reservoir effects, of the order of 10,000 ¹⁴C years, and we suggest that the presence of freshwater carbon is responsible for the anomalously early ages within our dataset. In pig samples, the majority of non-terrestrial carbon is freshwater in origin, but in human samples the proportion of freshwater carbon is within the error of the marine component (±10%). This presents a major obstacle to assessing temporal patterns in the ages of human remains from sampled graves, although the majority of grave ages are within the same, broad, calibrated range.     

Diet in medieval Denmark: a regional and temporal comparison

The aim of this research is to explore regional and temporal patterning in diet in medieval Danish populations. δ¹⁵N, δ¹³C_coll, δ¹³C_ap values were obtained from 154 human bone samples from three sites located in the Jutland peninsula of Denmark. These sites span the medieval period. The results suggest that the medieval Danish diet was composed of C₃ plants, terrestrial animals, and freshwater and marine fish in varying amounts. The data also suggest some regional patterning in diet, but little temporal differences in the composition of diet.     

Paleodiet reconstruction of Bronze Age Siberians from the mortuary site of Khuzhir-Nuge XIV,Lake Baikal

Paleodiet reconstruction using stable isotopes of carbon and nitrogen was carried out on individuals from the Bronze Age cemetery, Khuzhir-Nuge XIV on the western shore of Lake Baikal, Russian Federation. The cemetery contained 79 graves with 89 individuals and was in use between approximately 2700 and 2000 cal. B.C. with the exception of one burial, dated to around 4000 B.C. Archaeological and ethnographic evidence indicates that hunting and fishing were the main subsistence activities while gathering was less important. δ¹³C from collagen and carbonate apatite was analysed, along with δ¹⁵N from collagen. Bone mineral preservation was evaluated using Fourier transform infrared spectroscopy. δ¹³C and δ¹⁵N of collagen are positively correlated and reflect varying reliance on terrestrial mammals, fish, and seals from Lake Baikal. Lake Baikal biota exhibit considerable variation in δ¹³C at the base of the food web thus; there is variation in human δ¹³C (−20.1‰ to −16.2‰) despite the fact that there are no C₄ plants in the region. δ¹⁵N results (range 10.3‰–16.5‰) indicate that fish, and possibly seals, made up some of the diet for everyone, but in varying amounts relative to terrestrial herbivores. δ¹³C from carbonate is not correlated with δ¹³C from collagen, a situation that has been found in remains from other coastal sites. A mixed diet from both terrestrial and freshwater ecosystems is the most likely explanation. Analysis of mortuary variables within the cemetery reveals three distinct clusters of graves with variations in burial treatment among the clusters. δ¹⁵N values are significantly different among these clusters, suggesting an association between diet and mortuary customs.     

The impact of manuring on nitrogen isotope ratios in cereals: archaeological implications for reconstruction of diet and crop management practices

Recent archaeological studies of human diet have used stable nitrogen isotope ratios (δ¹⁵N) from human bone collagen to infer the relative importance of terrestrial plant and animal foods. This approach is based on widely observed enrichment of δ¹⁵N up the food chain, plants having distinctly lower values than the herbivores that consume them. Studies of early farming diets in Britain, Denmark and Germany have tended to detect relatively high δ¹⁵N values (e.g. c. +9‰), interpreted as evidence of a diet largely based on animal products, though archaeobotanical evidence for crop cultivation (e.g. carbonised cereal grain and chaff) is widespread. This paper investigates the impact of manuring on δ¹⁵N values in modern cereals, and of charring on these cereal values. The results from two long-term experiments demonstrate that manuring significantly raises δ¹⁵N in cereal grain and chaff. Depending on manuring levels and frequency, it appears that human diets with a major component of such grain would conventionally be interpreted as indicating a largely animal-based diet or a mixed plant/animal diet. Moreover, preliminary analyses of experimentally charred grain and chaff from manured and unmanured conditions are promising for the extraction of reliable ancient δ¹⁵N values from archaeobotanical cereal remains. The wider implications of these results, and the need for further work, are discussed.     

Stable isotope analysis of human and animal remains from the Late Upper Palaeolithic site of Balma Guilanyà, southeastern Pre-Pyrenees,Spain

Stable isotope analysis of carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) was performed on collagen extracted from three human and five herbivore bone and tooth samples from the Late Upper Palaeolithic site of Balma Guilanyà (Catalonian Pre-Pyrenees, Spain). Contextual and palaeoecological data as well as radiocarbon dates indicate that the studied occupation phase took placed during the Bolling/Allerod interstadial (GI-1a event). The human remains were co-mingled without any anatomical association, corresponding to a minimum number of three individuals, and it was not possible to determine if the three analyzed samples are from one or more individuals. The mean isotope values obtained from the human remains are δ¹³C = −19.8‰ and δ¹⁵N = 6.7‰, while those of the large herbivores (red deer and wild goat) were −19.8‰ and 1.7‰ for δ¹³C and δ¹⁵N respectively. This indicates that the main source of protein in the diet of the Balma Guilanyà human(s) came from terrestrial herbivores. There is no zooarchaeological or isotopic evidence for the consumption of freshwater or marine resources at the site, which lies 80 km from the present Mediterranean coast. The low δ¹⁵N values observed in both human and animal samples correspond to a trend reported by other researchers working in northwestern Europe: a significant δ¹⁵N reduction in collagen from bones datable within 20,000–10,000 BP, followed by a rise to present values in the Early Holocene. This phenomenon, generally attributed to climatic and/or pedological processes, had not been previously observed in the Mediterranean region and, until now, was thought to be restricted to northern Europe.     

Diet and mobility in Middle Archaic Florida: stable isotopic and faunal evidence from the Harris Creek archaeological site (8Vo24), Tick Island

We explore diet and mobility in Middle Archaic Florida using human burials and faunal remains from the Harris Creek archaeological site (8Vo24) on Tick Island. We conducted stable carbon and oxygen isotopic (δ¹³C, δ¹⁸O) analyses of 50 human enamel samples and strontium isotopic (⁸⁷Sr/⁸⁶Sr) analysis of a subset of 10. Most individuals (46/50) subsisted on local freshwater and terrestrial resources, with relatively depleted δ¹³C values (C₃) and δ¹⁸O values matching those of central and north Florida water resources within the St. Johns River valley. Eight of 10 burials have local, within valley ⁸⁷Sr/⁸⁶Sr values. Two human burials yield marine δ¹³C and ⁸⁷Sr/⁸⁶Sr values, which we interpret as evidence for across valley movement from the coast. Another two individuals show depleted δ¹⁸O values, likely obtained from northern rivers. We also identified potential food resources and non-local foods from the Harris Creek faunal assemblage. We found six species with estuarine and marine habitat preferences; two of which, whelk and quahog, indicate that people of Harris Creek traveled to or traded with coastal areas.     

Aquatic resources in human diet in the Late Mesolithic in Northern France and Luxembourg: insights from carbon,nitrogen and sulphur isotope ratios

We investigated the contribution of freshwater resources to the diet of seven Late Mesolithic hunter-gatherers (ca. 5300–7000 BC) from Northern France and Luxembourg using stable isotope ratios. In addition to the carbon and nitrogen stable isotope ratios (δ¹³C, δ¹⁵N), we explored the potential of the sulphur isotopic ratios (δ³⁴S) to detect and quantify the proportion of protein derived from aquatic foodstuff. In only two sites, animal remains from an associated settlement were available and subsequently examined to decipher the isotopic differential between terrestrial and freshwater resources. The quantification of their relative contribution was simulated using a Bayesian mixing model. The measurements revealed a significant overlap in δ¹³C values between freshwater and terrestrial resources and a large range of δ¹⁵N values for each food category. The δ³⁴S values of the aquatic and terrestrial animals were clearly distinct at the settlement in the Seine valley, while the results on fish from Belgium demonstrated a possible overlap in δ³⁴S values between freshwater and terrestrial resources. Local freshwater ecosystem likely contributed to ca. 30–40 % of the protein in the diet of the individuals found in the Seine settlement. Out of this context, the isotopic signature and thus contribution of the available aquatic foods was difficult to assess. Another potential source of dietary protein is wild boar. Depending on the local context, collagen δ³⁴S values may contribute to better assessment of the relative contribution of freshwater and terrestrial resources.     

Isotopic evidence of dietary variability in subadults at the Usu-moshiri site of the Epi-Jomon culture,Japan

This study reconstructs adult and subadult diets of a hunter-gatherer population of the Epi-Jomon culture (approximately 2300–1700 years BP) in Japan, using the stable isotopic analysis of carbon and nitrogen. The results suggest that the Usu-moshiri adults were highly dependent on marine resources such as seals for their dietary protein intake and that no significant dietary differences existed between the sexes. Among subadults we found two types of diet on the basis of different isotopic signatures. One group consisted of individuals with δ¹³C values below than those of the adult female mean minus two standard deviations and δ¹⁵N values lower than those of subadults in the other groups. These low-δ¹³C subadults indicated relatively less enriched δ¹⁵N values by 3.5 years of age at the latest. They probably consumed more ¹³C-depleted foods during weaning than in the ordinary adult diet. In the other high-δ¹³C group, their enriched δ¹⁵N values start to decline by four years of age and fall within the two-standard-deviations range of the total adult mean around five to six years of age. Isotopic values of children in this high-δ¹³C group suggest that they would have been fed ordinary adult diets during weaning. Perinates could also be divided into two groups on the basis of the similar patterns in their carbon and nitrogen isotope ratios. Our results indicate variabilities in the diets of subadults, and similar variabilities were also seen in ethnographic studies of the Ainu populations.     

Dietary change in Fijian prehistory: isotopic analyses of human and animal skeletal material

We examine evidence for prehistoric diet in the Fiji Islands through the analysis of stable isotope ratios (δ¹³C and δ¹⁵N) for 26 samples of human and animal bones from various archaeological sites, time periods, and local environments. The oldest individuals in this study, dating to about 2700 BP and living on the small island of Waya, consumed a predominantly marine-based diet. Subsequent populations on this island showed reduced consumption of marine resources, with greater reliance on terrestrial ones, throughout the cultural sequence. In contrast, populations of humans and pigs living inland on Viti Levu, the largest island, relied on terrestrial resources since at least 1500 BP. Thus, our results suggest that human and pig diets throughout Fijian prehistory relied variably on marine or terrestrial resources, and this distinction is largely a product of geography. This finding and our analyses provide a model for understanding ancient diets in Remote Oceania.     

Isotopic evidence for the reconstruction of diet and mobility during village formation in the Early Middle Ages: Las Gobas (Burgos,northern Spain)

Strontium, carbon, and nitrogen isotopes of human bone and tooth remains have been used to reconstruct residential mobility and diet of early medieval populations at Las Gobas from the sixth to eleventh centuries. Most non-local individuals correspond to the tenth to eleventh centuries and were mostly women and infants. This residential mobility coincided with the formation of Laño village and the abandonment of artificial cave settlement. Carbon and nitrogen isotope ratios of bone collagen indicate an omnivorous homogenous diet based on terrestrial plant resources, with few animal-derived proteins from livestock. Millet consumption was restricted to an earlier period of time (seventh to ninth centuries); and in later periods (tenth to eleventh centuries), mainly C₃ plants such as wheat and barley were consumed. In general, there were no dietary differences between individuals according to sex or age. Sex-related dietary differences have only been observed in the tenth to eleventh centuries, when females consumed a more vegetarian diet and less animal protein. The higher δ ¹⁵N values in infants reflect the weaning effect, while the differences in δ ¹⁵N values between young adult men and young adult women can be explained as a physiological factor related to pregnancy or different origins. In a comparison with contemporaneous medieval populations in the northern Iberian Peninsula, both δ ¹³C and δ ¹⁵N values suggest similar foodstuff resources and diet among Christian and Muslim populations.     

The sinking of the Mary Rose warship: a medieval mystery solved?

The cause of the sinking of Henry VIII's Vice Flagship, the Mary Rose, as she sailed out to meet the French fleet on 19th July AD 1545, has remained an enduring mystery and contested encounter between the English and French Navies. The French claim was that the ship was holed by French cannon fire, whilst the English maintained that she sank due to a poorly executed navigational manoeuvre during the engagement. On the day of the sinking there was a total listed crew complement of 415 men onboard. Minimum number analysis of the commingled human assemblage identified only 179, from which we sampled 18 individuals from differing decks within the ship. We measured δ¹³C and δ¹⁵N in bone collagen, and δ¹⁸O and δ¹³C in enamel apatite of these individuals in order to obtain information about their diets and origins. While the collagen δ¹³C and δ¹⁵N data are similar to other medieval populations, the δ¹⁸O data indicate that a significant proportion of the crew did not originate in Britain, but rather they emanated from warmer, more southerly, regions. These data suggest the presence of 33–60% of non-natives, possibly mercenaries and/or ‘prest’ men, amongst the crew. Together with the contemporary remark shouted from the Mary Rose to a passing ship, that the Captain had the “type of knaves of whom, he could not rule”, our results lend weight to the suggestion that poor communication may well have contributed the observed fatal navigational manoeuvre which led to her sinking.     

Modern and early-middle Holocene shells of the freshwater mollusc Unio, from Çatalhöyük in the Konya Basin, Turkey: preliminary palaeoclimatic implications from molluscan isotope data

Carbon and oxygen isotope ratios in the shells of the freshwater Unio mollusc yield information on the isotopic composition of the water in which the shell was formed, which in turn relates to climatic conditions prevailing during the bivalves’ life span. Here we analysed shells from one modern Unio, from a modern lake shore in Anatolia, and 4 subfossil Unio shells from Çatalhöyük (dated between 7200 BC and 5000 BC, Neolithic and Chalcolithic periods). Sequential carbon and oxygen isotope analysis along the surface of the shells provides information on seasonal or shorter-term variability of lake waters during the lifetime of the organisms. δ¹⁸O values of the modern shell are consistent with it being collected from a dammed portion of the Seyhan River that does not undergo intensive summer evaporation. This is in contrast to many of the surface water bodies in Anatolia which suffer extensive evaporation in the arid summers. δ¹⁸O values of the subfossil shells from the Çatalhöyük middens indicate that the bivalves came from lakes which evaporated extensively during the summer months but were replenished by high winter rainfall, suggesting that the subfossil shells lived in relatively small lakes or ponds. Stable isotope analysis along the growth of freshwater bivalves is one of the few methods for investigating seasonal water fluctuations in the past. These results may alter current interpretations on the environment of Çatalhöyük during the Neolithic, although more work is needed to confirm these initial findings.     

Implications of a freshwater radiocarbon reservoir correction for the timing of late Holocene settlement of the Elk Hills,Kern County,California

Uncertainties regarding the magnitude of freshwater radiocarbon reservoir effects can introduce random errors into dates on archaeological freshwater carbonates. As a result, many archaeologists avoid dating freshwater shells unless no other datable materials are available. The chronology of prehistoric occupation of the former Naval Petroleum Reserve No. 1 (NPR-1) at Elk Hills, Kern County, has been established with 50 radiocarbon dates on freshwater mussels (Gonidea and Anodonta sp.). Characterization of any freshwater radiocarbon reservoir effect is crucial for the accurate interpretation of inferred settlement and subsistence changes on the Elk Hills. Paired charcoal and freshwater mussels sampled from closely associated contexts were dated to identify a freshwater reservoir effect. Paired Anodonta and Gonidea sp. shells were dated to investigate interspecific differences in fractionation. Results indicate that a 340 ± 20 ¹⁴C yr correction should be applied to conventional ¹⁴C dates on freshwater carbonates in the Buena Vista Basin before calendar calibration. Evidence of interspecific differences is inconclusive. Dates recalibrated with the reservoir correction indicate that widespread occupation of the Elk Hills is correlated with increasing precipitation towards the end of the Medieval Climatic Anomaly and during the Little Ice Age, suggesting that slough resource exploitation may have been driven by regional population pressure rather than drought-related declines in aquatic productivity.     

Stable carbon and nitrogen isotope ratios of bone collagen: Variations within individuals,between sexes,and within populations raised on monotonous diets

The stable carbon and nitrogen isotope ratios of collagen of seven bones from each of three rabbits raised on a monotonous diet, and of two bones from each of eight female and seven male mink raised on another monotonous diet, were determined. The ranges of δ¹³C values and δ¹⁵N values were 0·5‰ and 0·6‰ for the rabbit bones and 1·0‰ and 1·4‰ for the mink bones. Uncertainties in the δ¹³C and δ¹⁵N values for prehistoric human diets estimated from the isotopic composition of collagen from the small numbers of bones which are typically available for analysis, and thus likely to be of the order of ±1‰.     

Understanding the variability in freshwater radiocarbon reservoir offsets: a cautionary tale

Freshwater resources in past diets can lead to inaccuracies when attempts are made to ascertain their radiocarbon ages or those of the consumers. Radiocarbon reservoir effects may lead to significant age offsets when the bones or other tissues of these consumers are radiocarbon dated. A number of recent studies have investigated freshwater reservoir offsets. However no study thus far has satisfactorily obtained a ubiquitous freshwater reservoir correction due to variability in the ecosystems analysed. This study tests the possibility of predicting freshwater reservoir effects from the carbonate alkalinity of the water with measurements on modern fish bone and water samples. A predictive capability would be especially valuable in the absence of well-preserved archaeological fish bone. We surveyed samples from lakes and rivers in varying geological settings in Britain and Ireland. Modern fish bone and water samples were analysed to investigate modern radiocarbon offsets from the atmosphere. Archaeological fish bone was also analysed to examine past reservoir offsets at selected sites. Stable carbon and nitrogen isotope values were measured to aid in interpretation of any variability in the offsets. Large freshwater reservoir offsets were measured in some modern and archaeological samples (maximum offset = 1638 ¹⁴C years). The freshwater reservoir offsets in the fish bone were highly correlated with alkalinity of water in modern lake sites analysed. However, a high amount of variation within and between fish species was also evident in the results, precluding the possibility of providing regional corrections for freshwater reservoir offsets from alkalinity although this still may provide a general guideline. The variability is thought to be due to differences in the diet of individual fish.     

Dietary reconstruction in Migration Period Central Germany: a carbon and nitrogen isotope study

This study presents bone collagen carbon and nitrogen isotope data from the Migration Period cemeteries (fifth/sixth century AD) of Obermöllern and Rathewitz in Central Germany. The human average δ ¹³C ratios of ?19.8?±?0.3 ‰ and δ ¹⁵N ratios of 9.6?±?0.9 ‰ (n?=?43) reflect a mixed diet in a temperate C3-based ecosystem without significant difference between the two sites. The average offset between human and faunal δ ¹³C and δ ¹⁵N values indicates a significant contribution of plant food to the human diet that has different isotope ratios from the forage of the animals. It furthermore suggests the influence of land management on the δ ¹⁵N values. One adult male from Obermöllern stands out due to his elevated nitrogen isotope ratio, body height, grave goods, and burial position. The collagen isotope data of this study are comparable with data from other central European sites and confirm rather stable communities with moderate variation in the environmental conditions of arable land.     

Stable isotope analysis of 14 individuals from the Mesolithic cemetery of Vasilyevka II,Dnieper Rapids region,Ukraine

Bone collagen extracted from 14 humans from the Mesolithic cemetery of Vasilyevka II was analysed for their δ¹³C and δ¹⁵N ratios. This cemetery is one of only two later Mesolithic cemeteries from the Dnieper Rapids region, being dated to 7300–6220 cal BC on the basis of three radiocarbon determinations. This analysis provides insights into the nature of the diet of the Dnieper populations at the very end of the Mesolithic period, prior to the adoption of pottery in the region, and the assumed shift towards the exploitation of domesticates in the economies of the populations of the Dnieper region, and considers these in relation to broader temporal indicators of diet in the region.     

Early Neolithic diet and animal husbandry: stable isotope evidence from three Linearbandkeramik (LBK) sites in Central Germany

The first appearance of the Neolithic Linearbandkeramik (LBK) in Central Germany occurred during the 6th millennium BC. However, though LBK sites are abundant in the German loess areas, there are only a few studies that reconstruct the diet of these first farmers using biochemical methods. Here we present the largest study undertaken to date on LBK material using stable isotope analysis of carbon and nitrogen to reconstruct human diet and animal husbandry strategies. We analyzed the bone collagen of 97 human individuals and 45 associated animals from the sites of Derenburg, Halberstadt and Karsdorf in the Middle Elbe–Saale region of Central Germany. Mean adult human values are ?19.9 ± 0.4‰ for δ¹³C and 8.7 ± 0.8‰ for δ¹⁵N. The δ¹³C values are typical for terrestrial, temperate European regions, whereas the δ¹⁵N values fall within an expected range for farming societies with a mixed diet consisting of products from domestic animals and plants. The consumption of unfermented dairy products is unlikely as there is direct palaeogenetic evidence of lactose intolerance available for one of the sites. There are no clear indications for dietary differences in sex. Young children under three years of age are enriched in δ¹⁵N due to breastfeeding indicating that weaning likely occurred around the age of three years. The fauna exhibit mean δ¹³C values of ?20.9 ± 0.8‰ and mean δ¹⁵N values of 7.0 ± 0.9‰ respectively. Variation in the δ¹³C and δ¹⁵N in the domestic animals is probably caused by different livestock managements.     

Diet in the Iron Age cemetery population at Wetwang Slack,East Yorkshire,UK: carbon and nitrogen stable isotope evidence

This paper reports δ¹³C and δ¹⁵N values for human and animal bone collagen from the middle Iron Age site at Wetwang Slack, East Yorkshire, UK. The data indicate a human diet which was high in animal protein, with no evidence for any significant marine food input. No differences were found between high-status vehicle (or ‘chariot’) burials and the rest of the population and no other status differentiations are visible according to burial rite, age or sex groupings, although the data obtained for the older males display an unusual trend. No dietary variation is seen between two site phases and no evidence for an early immigrant group is present. The range of isotope values for the adult human group as a whole is small, indicating that the diet is likely to have been consistent over time and across the population, although two individuals stand out as unusual amongst the 62 analysed.     

Fast or feast: reconstructing diet in later medieval England by stable isotope analysis

In this pilot-study, which was designed to assess the range of isotopic variation in English medieval populations, we present the results of stable isotope analysis of carbon and nitrogen of human and animal bone collagen from three later medieval sites in Northern England.The isotopic values observed for the rural hospital of St. Giles by Brompton Bridge (N. Yorks.), the Augustinian Friary at Warrington and a mass-grave with casualties from the Battle of Towton (N. Yorks.) are significantly different from those reported for other archaeological populations in Britain, namely by their very enriched δ¹⁵N ratios which are combined with almost entirely terrestrial carbon signals. We discuss possible explanations for the unusual human data and argue on grounds of the available faunal data, that a mixed diet of terrestrial, marine and freshwater resources is most likely. This may indicate the significant impact of the medieval fasting regulations on everyday subsistence. We conclude that stable isotope analysis can complement the available historical information on diet in the Middle Ages.