Strontium isotope evidence of migration and diet in relation to ritual tooth ablation: a case study from the Inariyama Jomon site,Japan

Ritual tooth ablation was extensively practiced among Jomon (Japanese Neolithic) societies in their final phase (ca. 3000-2300 BP). This tradition includes two different tooth ablation patterns, type 4I and type 2C, referring to extraction of the mandibular incisors and canines, respectively. However, the reason for this difference is unclear. Previous carbon and nitrogen stable isotope analysis of human remains from the Inariyama shell mound revealed that type 4I individuals were more dependent on terrestrial resources and type 2C individuals on marine resources. To test this hypothesis, we performed strontium (Sr) isotope (⁸⁷Sr/⁸⁶Sr) analyses on the same skeletal remains and on modern plants around the site. Because Sr isotope ratios of plants differ according to the local geology and seawater has a consistent Sr isotope ratio, the Sr isotope ratios of tooth enamel can reveal both migration and diet. Comparing Sr isotope ratios in plants and seawater with those of tooth enamel, we identified four possible immigrants. Type 4I locals had significantly higher Sr isotope ratios than type 2C locals. The ratios of the type 4I and type 2C locals were close to those of terrestrial plants and seawater, respectively, suggesting that type 4I locals had incorporated much Sr from terrestrial resources and type 2C locals from marine resources. These results support the hypothesis that ritual tooth ablation reflects dietary differences throughout an individual’s life, and they suggest possible occupational differentiation among the Jomon people.     

Strontium and calcium distribution in plants: Effect on palaeodietary studies

In palaeodietary studies it is assumed that no discrimination occurs during uptake by plants of calcium and strontium from the soil. Here, a compilation of distribution ratios is presented from which it is apparent that differences in Sr/Ca ratios within and between plants do exist. These differences affect Sr intake by humans and animals and thus should be taken into consideration when interpreting prehistoric human bone Sr levels in a dietary sense, and when selecting a herbivorous baseline species. In agricultural societies, human Sr intake may be diversified by differences in Sr/Ca ratios in various grain species and varieties.     

THE FUNDAMENTAL RELATIONSHIP BETWEEN ANCIENT DIET AND THE INORGANIC CONSTITUENTS OF BONE AS DERIVED FROM FEEDING EXPERIMENTS

The levels of ten elements (phosphorus, calcium, magnesium, strontium, barium, potassium, sodium, zinc, iron, and aluminium) have been measured in the femurs and humeri of laboratory rats grown on test diets as a model for palaeodietary studies of excavated human skeletons. High levels of dietary fibre correlate with lower Ca and higher Sr and Ba in the bone. High values of the dietary Sr/Ca ratio correlate with high Sr levels in the bone. High levels of dietary protein correlate with lower Sr and higher Zn. High values of the ratio Ba/Ca and lower levels of Fe correlate with higher levels of Ba. Because bone levels typically are controlled by several dietary components, variation of the levels of a given element in the diet does not necessarily translate into analogous variations in bone. Only K and Fe in bone correlate highly with their levels in diet. The failure of bone Sr, Ba, and Zn to correlate positively with dietary levels is fully explicable in terms of their interdependence on other dietary components, such as Ca, P, Fe, protein, and fibre.     

Identifying food provenience using Sr/Ca ratio in human enamel

The strontium (Sr) concentration in bioapatite of human bone and teeth reflects the Sr concentration in food that is differentiated by two major factors: an abundance of Sr in local soils and the biopurification effect along the trophic levels. Eastern Syria is an area with a relatively high concentration of Sr within the Euphrates valley and a low concentration of Sr beyond the valley. For this reason, the strontium/calcium (Sr/Ca) ratio in human enamel retrieved from skeletons buried in cemeteries within the Euphrates valley may be used as a proxy for food provenience in a local population. A sample of human teeth (N = 72) from Tell Ashara and Tell Masaikh was divided into seven temporal subsets covering periods between c.2200 bce and the early 20th century ce . A significant difference in Sr/Ca values between temporal subsets is observed. The Sr/Ca values in later subsets are negatively correlated with δ¹³C values, indicating the wider exploitation of steppe areas outside the valley with more wild C4 grasses and a low Sr concentration. For periods with lower Sr/Ca values (c.2200–1900 bce and 19th–20th centuries ce ) there is additional textual and isotopic evidence for food transportation from outside the river valley, supporting the interpretation of Sr/Ca values as a proxy for food provenience in this specific area.     

Introducing δSr analysis in archaeology: a demonstration of the utility of strontium isotope fractionation in paleodietary studies

Isotopic methods are widely used in archaeology to investigate paleodiet. Here, we present a new method to identify trophic level in archaeological human populations and to investigate paleodiet. We demonstrate that strontium isotope compositions (reported as δ^88/86Sr) vary in a mass-dependent manner with increasing trophic level and can elucidate paleodiet in archaeological human populations. We present new mass-dependent strontium isotope data from tooth enamel and bone from individuals buried during the Late Intermediate Period (c. AD 1000–1300) in the large cemeteries of Chiribaya Alta, Chiribaya Baja, San Gerónimo, and El Yaral in the Ilo and Moquegua Valleys of southern Peru. We compare these data to radiogenic strontium isotope data (⁸⁷Sr/⁸⁶Sr) and light stable isotope data (δ¹⁵N_col and δ¹³C_col) from the same individuals to investigate geologic variability in strontium sources as well as marine food consumption among the Chiribaya. Our results demonstrate the utility of measurements of strontium isotope fractionation as a new tool for archaeological investigation of paleodiet. Importantly, this new technique can be used to generate paleodietary (δ^88/86Sr) and paleomobility (⁸⁷Sr/⁸⁶Sr) data from the same specimen, minimizing destructive analyses of invaluable archaeological material, and provides a new way to examine paleodiet through hydroxyapatite, which is particularly important when collagen is poorly preserved.     

Carbon and nitrogen stable isotope analysis on the diet of Jomon populations from two coastal regions of Japan

We report on a stable isotope paleodietary reconstruction of Jomon populations in Japan during the Middle to Final Jomon period (ca. 5000–2300 years BP), focusing on dietary differences within and among populations and between regions. Carbon and nitrogen isotope analysis was performed on human and faunal bone collagen from six coastal sites along the Inland Sea in the Sanyo (Ota, Funamoto, and Tsukumo) region and along Mikawa Bay and the Pacific Ocean in the Tokai (Kawaji, Yoshigo, and Inariyama) region. We found that carbon and nitrogen isotope ratios were positively correlated, indicating that the Jomon people consumed a mixed diet of marine (shellfish and marine fish) and terrestrial (C₃ plants and terrestrial mammals) protein. In the Ota samples (n = 25, during the Middle Jomon period, 5000–4000 years BP), sex was one of the main reasons for the intra-population dietary variation. Ota males consumed greater amounts of marine food, while Ota females consumed greater amounts of terrestrial food; these dissimilar diets may have been related to the sexual division of labor. Significant inter-population dietary differences were found, which may have been related to differences in age or site location. Notably, the two coastal regions showed clear isotopic differences. Nitrogen isotope ratios of individuals from the Sanyo region were significantly higher than ratios of individuals from the Tokai region. The individuals in the Sanyo region might have consumed a diet high in aquatic foods, particularly high trophic level marine fish, whereas the individuals in the Tokai region might have consumed a lot of marine shellfish. Another possible reason for the regional isotopic difference might have been different baseline of nitrogen isotope ratios of the marine ecosystems.     

The Ba/Sr ratio,carious lesions,and dental calculus among the population buried in the church La Concepción (Tenerife,Canary Islands)

Certain trace elements may accumulate in bone in relation to dietary habits, so some of them are of interest in paleodietary analysis. This is the case with strontium (Sr) and barium (Ba), whose potential value as paleodietary indicators is enhanced by their relatively inert metabolic behaviour. The presence of carious lesions may indicate consumption of sugar and vegetables, whereas the etiology of dental calculus deposition is multifactorial, although some authors consider this as an indicator of protein consumption. Based on these facts we analysed (1) Ba, Sr, and calcium (Ca) content of inner cortical bone obtained from the ramus mandibularis, by atomic absorption spectrophotometry, (2) presence of teeth with carious lesions, and (3) presence of teeth with calculus deposition in 62 mandibles. All samples were obtained from the church La Concepción, an 18th century burial place in Tenerife. Gender was assessed by analysing genetic expression of amelogenin in some cases (14), and by inspection of pelvic bones when available (41 cases). We found (1) Carious lesions in 32 cases, and dental calculus, in 39; no association was observed between sex and presence of dental caries or calculus deposition, nor between the sex and the proportion of carious teeth nor the proportion of teeth with calculus deposition; (2) people buried near the altar (priests and individuals of the highest social class) showed a significantly higher proportion of teeth with dental calculus deposition (χ² = 5.36, p = 0.021); (3) bone Sr and bone Ba were significantly higher than the values observed in a control group of 10 modern omnivorous individuals; the lowest Sr values were observed among people buried near the altar; and (4) the Ba/Sr ratio was directly related with the proportion of teeth with carious lesions. These data suggest that there were differences in dietary pattern among the individuals belonging to different social classes; overall, consumption of vegetables was widespread, as shown by the high proportion of carious lesions, in relation with raised Ba/Sr ratio, whereas consumption of marine products was scarce.     

Assessing the life history of an andean traveller through biogeochemistry: Stable and radiogenic isotope analyses of archaeological human remains from Northern Chile

Bioarchaeology and biogeochemistry can elucidate aspects of individual life histories that are often lost in the archaeological record. Here, we use stable and radiogenic isotope analyses of enamel, bone and hair to reconstruct paleodiet and paleomobility in an adult male interred along a pre‐Columbian route connecting the northern Chilean coast to the inland Loa River Valley. Although this well‐preserved burial included mortuary goods typical of coastal cultures, it was discovered in a vast, uninhabited part of northern Chile's hyper‐arid Atacama Desert. Variation in carbon and nitrogen isotopes reflects dietary differences, while strontium and oxygen isotopes vary geologically and geographically. We use these data to examine paleodiet and paleomobility and to assess whether this was a coastal traveller seeking provisions from the interior or vice versa. Enamel stable isotope analysis is consistent with the consumption of a mixture of terrestrial and marine resources during the first years of life. Bone stable isotope analyses indicate habitual consumption of marine foodstuffs over the last 10–30 years of this individual's life. Interestingly, stable isotope analysis of hair samples provides more fine‐grained information on this individual, suggesting movements between the coast and highlands in the months before his death. Radiogenic strontium isotope data are consistent with residence on the coast or in the Atacama Desert, but are lower than strontium isotope values from higher altitudes. These dietary and geological patterns are reconcilable with coastal residency; the isotopic data are consistent with foodstuffs and textiles found with the burial. Therefore, we argue that this individual was regularly moving from the coast to inland areas, crossing the hyper‐arid Atacama Desert by following strategic interzonal routes that provided access to particular resources. Copyright © 2010 John Wiley & Sons, Ltd.     

Reconstructing Middle Horizon mobility patterns on the coast of Peru through strontium isotope analysis

The pre-Columbian coastal site of Ancón, Peru frequently has been interpreted as an important outpost of the highland Wari Empire, inhabited by individuals from the sierra and the coast. In order to test this hypothesis, bone–tooth pairs from 35 Middle Horizon (550 AD–1000 AD) Ancón skeletons were analyzed for strontium isotopes, which vary by geologic provenance. Results indicate that 34 of the 35 individuals have ⁸⁷Sr/⁸⁶Sr enamel and bone values higher than Ancón's biologically available strontium isotope range. Nitrogen and carbon isotope data from a subset of the Ancón skeletons suggest that the higher than expected ⁸⁷Sr/⁸⁶Sr values among the Ancón sample likely reflects a diet rich in marine resources rather than migratory activity, and highlight the need to use multiple lines of evidence to track residence change at sites where individuals relied on resources other than locally grown terrestrial foods. The one remaining individual, a young female of elite status, has an enamel strontium isotope signature much lower than the available data for local fauna and soil indicating that she was not raised locally. Her enamel ⁸⁷Sr/⁸⁶Sr ratio fits well within the range of strontium isotope values established for the inland Wari site of Conchopata [Tung, T.A., Knudson, K.J. Social identities and geographical origins of Wari trophy heads from Conchopata, Peru. Current Anthropology, in press.], and suggests that highland, Wari immigrants may have been present at Ancón during the Middle Horizon.     

Bone chemistry and the reconstruction of diet: Strontium discrimination in white-tailed deer

Studies of the relationship between the strontium content of human bone and past diet are still in an experimental stage. Because of the low frequency of carnivore remains at most archaeological sites and the absence of information on local strontium levels, it has been difficult to (1) estimate dietary intake for a prehistoric population, and (2) to compare prehistoric populations from spatially disparate areas. However, examination of strontium/calcium ratios in a modern herbivore may help to alleviate these problems. Bones from modern white-tailed deer (Odocoileus virginianus) were compared with deer diet in Wisconsin. An observed ratio between deer bone and diet in terms of a strontium/calcium index was calculated at 0204, which compares favourably with observed ratios reported for other mammals. Prehistoric white-tailed deer are used in the analysis of two Late Archaic sites in the midwestern U.S.A. The strontium levels in deer can be used as a baseline for comparison between sites. The prehistoric subsistence patterns are generally comparable, with hunting accounting for the bulk of the diet.     

Strontium isotopic characterization of the Palmottu hydrosystem (Finland): water–rock interaction and geochemistry of groundwaters

The Palmottu hydrosystem is located in a granitic host rock in southern Finland. Along well‐defined pathways in the fractured crystalline rock, strontium isotopes are used to trace the degree of water–rock interaction (WRI) and mixing processes in groundwaters. The ⁸⁷Sr/⁸⁶Sr ratios range between 0.716910 and 0.735606 in the surface waters and between 0.719991 and 0.750787 in the groundwaters, but are between 0.720 and 0.735 in most of the samples. Moreover, the results show a lack of correlation between the water chemistries determining the classification into different water‐types (Na–Cl, Na–SO₄, etc.) and the results of the strontium (Sr) contents and Sr isotopic ratios. From a WRI standpoint, this implies that the Sr behaviour is independent of the water chemistry; the occurrence of large ⁸⁷Sr/⁸⁶Sr variations is site specific and mainly dependent on the lithology. A model to determine the ⁸⁷Sr/⁸⁶Sr ratio of water after interaction with granite was developed. This model is based on the assumption that Sr was derived from three minerals: plagioclase, K‐feldspar and biotite. The results of the calculation indicate that around half of the water analysed within the Palmottu hydrosystem can be explained by the weathering of the granites. However, clearly lower ⁸⁷Sr/⁸⁶Sr are observed in waters when compared to the calculated ⁸⁷Sr/⁸⁶Sr and other sources of Sr, with low ⁸⁷Sr/⁸⁶Sr, rather than the calculated granite–water interaction, which may be suspected. When comparing the ⁸⁷Sr/⁸⁶Sr and ion ratios (Ca/Na, Mg/Na, Sr/Na, Cl/Na), the scattering of the data can be explained by the presence of four end‐members: a brine component (low ⁸⁷Sr/⁸⁶Sr and Ca/Na ratios…), a deep granitic component (high ⁸⁷Sr/⁸⁶Sr ratios and low Ca/Na ratios…), a subsurface component (intermediate ⁸⁷Sr/⁸⁶Sr ratios associated with high Ca/Na ratios…) and a surface end‐member:snow and river drainage (low ⁸⁷Sr/⁸⁶Sr and low Ca/Na ratios…). These extreme end‐members define a series of WRI‐mixing line within a rather complex hydrosystem.     

Oxygen and strontium isotopes as provenance indicators of fish at archaeological sites: the case study of Sagalassos,SW Turkey

In this paper, we investigate the potential use of oxygen and strontium isotope ratios (δ¹⁸O_p and ⁸⁷Sr/⁸⁶Sr) measured in archaeological fish enamel as provenance indicators. δ¹⁸O_p and ⁸⁷Sr/⁸⁶Sr were measured in a suite of archaeological carp remains recovered from the Anatolian townsite of Sagalassos dated to the Early Byzantine period (AD 450–650) and compared to that of modern fish, river and lake waters from the Anatolian region. We used sequential leaches in weak acetic acid to remove diagenetic Sr from fossil tooth enamel, monitoring the effectiveness of this approach by measuring the Sr/Ca ratios of the leachates via an isotope dilution thermal ionization mass spectrometry method (ID-TIMS). δ¹⁸O_p values mostly excluded a riverine origin. ⁸⁷Sr/⁸⁶Sr ratios of one fish overlapped with the ⁸⁷Sr/⁸⁶Sr signatures of two lakes in the Anatolian region, and at least one lake (Gölcük) could be removed as a candidate owing to a very distinctive ⁸⁷Sr/⁸⁶Sr signature not found in any of the fish remains. Most of the tooth samples analyzed could not be assigned a precise geographical origin since the ⁸⁷Sr/⁸⁶Sr ratios measured in enamel did not match that of any of the local lakes selected as potential origin. This result suggests that carp may have originated from lakes that have not yet been sampled, although this conclusion is not supported by other archaeological evidence. Alternatively, the lack of correspondence between lakes and fish Sr isotope ratios highlights several possible sources of uncertainties including spatial heterogeneity in ⁸⁷Sr/⁸⁶Sr ratio within a lake, the contribution of dietary strontium to the ⁸⁷Sr/⁸⁶Sr ratio of fish tooth enamel, and post-mortem alteration of the tooth Sr isotope signal during fossilization. In spite of the high precision of the strontium isotope analyses and the wide range of variation in the surface waters of the Anatolian lakes and rivers, this method may remain limited to distinguishing between lakes situated in regions of bedrock of very distinct age and geology until these sources of uncertainty are more fully investigated.     

Stable Isotopic Evidence of Ancient Maya Diet at Caledonia,Cayo District,Belize

The skeletal remains of 18 individuals interred at the ancient Maya site of Caledonia (100 to 1000 C.E.), located in the Cayo District of Belize, w ere sampled for stable carbon and nitrogen isotope analysis in order to reconstruct their diet. Stable carbon and nitrogen isotope ratios in 18 bone collagen samples and stable carbon isotope ratios in bioapatite from 15 bone and 6 tooth enamel samples were assessed. Small sample sizes precluded the assessment of dietary variation with respect to age, sex, social status or time period among the Caledonia Maya. However, the sampled individuals consumed a varied diet consisting of maize, supplemented with some C₃ plants, terrestrial herbivores and/or lower order freshwater resources such as snails and molluscs and possibly maize‐fed animals. This dietary variability with an emphasis on maize is unsurprising given the biological diversity surrounding the site and the known importance of this crop to the ancient Maya. As expected, the isotopic values from Caledonia are similar to those from nearby sites from similar time periods. However, four individuals exhibit a marine dietary signature, possibly indicating inland trade of marine resources from coastal sites, or the migration of coastal people to Caledonia. This study demonstrates the validity of sampling small, fragmented collections from minor Maya centres in order to gain valuable insight into ancient Maya dietary practices. Copyright © 2013 John Wiley & Sons, Ltd.     

Variation in strontium isotope ratios of archaeological fauna in the Midwestern United States: a preliminary study

Strontium isotope values (⁸⁷Sr/⁸⁶Sr) in bone and tooth enamel have been used increasingly to identify non-local individuals within prehistoric human populations worldwide. Archaeological research in the Midwestern United States has increasingly highlighted the role of population movement in affecting interregional cultural change. However, the comparatively low level of geologic variation in the Midwestern United States might suggest a corresponding low level of strontium variation, and calls into question the sensitivity of strontium isotopes to identify non-local individuals in this region. Using strontium isotopes of archaeological fauna, we explore the degree of variability in strontium ratios across this region. Our results demonstrate measurable variation in strontium ratios and indicate the potential of strontium analysis for addressing questions of origin and population movement in the Midwestern United States.     

Micro-sampling of human bones for mobility studies: diagenetic impacts and potentials for elemental and isotopic research

The nature of long bone formation and the pathways of interaction between bone samples and the burial environment suggest that portions of the bones disconnected from the arterial system are resistant to diagenetic alteration. Preliminary work on femurs from Early Bronze Age hunter-gatherers in Cis-Baikal, Siberia shows that the nature and progression of chemical changes in the bone matrix due to microbial attack can be analyzed using laser ablation inductively coupled plasma mass spectrometry. Intra-osteon variability in elemental concentrations and strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) indicate the presence of unaltered portions of bone within diagenetically modified bone and suggest that useful data remain accessible. These biogenic signals can potentially be useful for mobility research in broad terms and the smaller timescales within an individual's lifetime (months, years), accessible therein. Laser ablation micro-sampling of femur specimens showed that intra-osteon elemental composition of Ba, Re, and Cs varied within and was correlated between multiple osteons of a single bone. Portions of chemically unaffected bone were identified within, and effectively discriminated from diagenetically altered bone tissue. Areas showing visual alterations and erratic or uncorrelated Ca and Sr elemental results also had anomalous Sr isotope ratios, suggesting diagenetic alteration in those places. Compositional and isotopic analysis of intact portions of bone supports the hypothesis that hunter-gatherer groups in Cis-Baikal made numerous major movements during their lives. Microscopic analysis of long bones clarifies aspects of biodeterioration and correlations between trace elemental results and diagenetic alteration. Micro-sampling of intact portions of bone expands the scope of available materials for research on mobility and other aspects of human past behavior.     

Paleodietary analysis of a San Francisco Bay Area shellmound: stable carbon and nitrogen isotope analysis of late Holocene humans from the Ellis Landing site (CA-CCO-295)

The late Holocene archaeofaunal record of the San Francisco Bay Area demonstrates temporal declines in the abundance of low-cost, high-ranked marine and terrestrial resources. During later periods of occupation, faunal assemblages are often dominated by lower-ranked, higher-cost resources, suggesting an increase in diet breadth through time. Archaeological resource intensification models argue that this marks a late Holocene decline in foraging efficiency in the Bay Area, driven by human-induced harvest pressure. This study examines dietary change in the region using stable carbon and nitrogen isotope data from 65 human burials, spanning two temporal components (cal AD 55–890 and cal AD 762–1550) at the Ellis Landing site (CA-CCO-295). The strong linear relationship between collagen carbon and nitrogen isotope values reflects both marine and terrestrial food consumption, with individuals showing a high level of dietary variability at the site. No temporal trend or meaningful sex differences were found in isotope values. The widening of diet breadth predicted by the archaeofaunal record occurred prior to the occupation of the Ellis Landing shellmound site. The trend in exploiting a greater amount of terrestrial resources during the Middle and Late Period in central California was supported by isotopic evidence.     

Strontium Isotopes in the Investigation of Early Glass Production: Byzantine and Early Islamic Glass from the Near East*

⁸⁷Sr/⁸⁶Sr ratios have been determined for glasses from four production sites, dated to between the sixth and the 11th centuries, in the Eastern Mediterranean region. On the basis of elemental analyses, the glasses at each location are believed to have been melted from different raw materials. Two glass groups, from Bet Eli‘ezer and Bet She‘an, in Israel, are believed to have been based upon mixtures of Levantine coastal sands and natron, and have ⁸⁷Sr/⁸⁶Sr ratios close to 0.7090, plus high elemental strontium, confirming a high concentration of modern marine shell (⁸⁷Sr/⁸⁶Sr ~ 0.7092) in the raw materials. The isotopic compositions of these two groups of glasses differ slightly, however, probably reflecting a varying ratio of limestone to shell because the sands that were utilized were from different coastal locations. Natron‐based glasses from a workshop at Tel el Ashmunein, Middle Egypt, have ⁸⁷Sr/⁸⁶Sr values of 0.70794–0.70798, and low elemental strontium, consistent with the use of limestone or limestone‐rich sand in the batch. High‐magnesia glasses based on plant ash, from Banias, Israel, have ⁸⁷Sr/⁸⁶Sr values of 0.70772–0.70780, probably reflecting the isotopic composition of the soils that were parental to the plants that were ashed to make the glass. Strontium and its isotopes offer an approach to identifying both the raw materials and the origins of ancient glasses, and are a potentially powerful tool in their interpretation.     

Brackish water foraging: isotopic landscapes and dietary reconstruction in Suisun Marsh,Central California

While bone stable isotope signatures of humans foraging in open coastal and fully terrestrial environments have been relatively well documented, the signature of foraging near brackish-water estuaries is less well known. This study examines the Central California isotopic landscape, or isoscape, showing how foods in different ecosystems have distinctive isotopic compositions. We present new bone collagen and apatite stable isotope data from two Late Holocene sites (CA-SOL-11 and CA-SOL-69) near Suisun Marsh, a low salinity brackish water estuary upstream from San Francisco Bay. Faunal remains at the sites include significant numbers of aquatic resources including fish and shellfish, in addition to terrestrial mammals, while paleobotanical remains suggest mainly terrestrial nuts and seeds. Stable isotope data at the population level corroborate this finding and show consumption of significant levels of brackish water nutrients, including both dietary protein and dietary carbohydrates and fats, paired with terrestrial foods. This dietary focus generates a unique brackish-water isotopic signature that is distinct from others in Central California. The documentation of an isoscape with strong regional gradients can be of tremendous help in reconstructing ancient patterns in subsistence, migration, and trade.     

Identifying locals, migrants, and captives in the Wari Heartland: A bioarchaeological and biogeochemical study of human remains from Conchopata, Peru

The site of Conchopata in the central Peruvian Andes was the secondary center in the heartland of the Wari Empire (AD 600–1000), and in this study we examine whether this urban locale was populated by locals, voluntary migrants from distant regions, and/or captives who were forcibly brought to Conchopata. We examine radiogenic strontium isotope ratios from 72 dental enamel and bone samples representing 31 formal burials and 18 human trophy heads to distinguish between locals and non-locals, and we examine skeletal and archaeological data to establish whether non-local persons were voluntary migrants or captives. We also describe a new, straightforward technique in the evaluation of radiogenic strontium isotope ratios to assist in detecting non-locals when large datasets are available.Results show that natal Conchopata inhabitants should exhibit radiogenic strontium isotope ratios that range from ⁸⁷Sr/⁸⁶Sr = 0.70548 to ⁸⁷Sr/⁸⁶Sr = 0.70610. Thus, among the 31 burials, 29 exhibit local values, suggesting that Conchopata was not a cosmopolitan center to which numerous foreigners migrated; rather, it was populated by local peoples, likely the descendants of the preceding Huarpa culture. The two individuals with non-local radiogenic strontium isotope ratios are an infant and a 17–22 years old female. The archaeological context suggests that the female may have been taken captive for subsequent sacrifice, as she was interred in front of the ritual D-shaped structure in which decapitated human heads (trophy heads) and sacrificed camelids were deposited. Among the 18 trophy heads sampled, 14 have non-local values, confirming previous studies of smaller samples that suggested that Wari warriors travelled to other locales and took captives—both adults and children—for subsequent transformation into trophy heads. Additional analyses of bone-tooth pairs from a subsample (12 burials and six trophy heads) shows that the burial group was much more sedentary (homogenous radiogenic strontium isotope ratios in bones and teeth) and the trophy head individuals were much more mobile (heterogenous radiogenic strontium isotope ratios in bones and teeth). Overall, the multiple lines of evidence support the notion that the Wari Empire occasionally used militaristic means, combined with elaborate ritualism, to subjugate other populations, a tactic that may have helped Wari establish and maintain control in particular regions in the Andes.     

Development of successive karstic systems within the Baix Penedès Fault zone (onshore of the Valencia Trough,NW Mediterranean)

The Baix Penedès Fault zone records successive karstic systems. The outcrops studied correspond to different segments of the fault, which were temporarily connected and disconnected, allowing for different diagenetic processes to occur. The first karstic system affected the Mesozoic rocks due to subaerial exposure after Paleogene compression, an event characterized by widespread dissolution and the generation of vug and cavern porosity. The δ¹⁸O values of the dolomitic sediment filling the initial vuggy porosity are similar to those of the host dolomite, indicating that the sediment comes from the erosion and reworking of the host rock. The second karstic system is related to the upward propagation of the Baix Penedès Fault. This deformation was characterized by random‐fracture fabrics with dolomite cement and sediment. The stable isotopes values and Sr/Ca ratios of both the dolomite cement and sediments are similar to those of the host rock. In contrast, the more depleted δ¹³C values indicate the influence of soil‐derived CO₂ and the opening of the system to meteoric waters. During the third karstic event, the δ¹⁸O, δ¹³C, Sr/Ca ratios, and ⁸⁷Sr/⁸⁶Sr values of diagenetic cements suggest a marine signature, indicating that the karstic sediments were dolomitized under the influence of late Burdigalian‐Langhian marine waters. These marine waters were probably expelled from poorly buried sediments and circulated through faults producing dolomitization of the karstic sediments. A final karst system developed during a period of uplift and subaerial exposure. The δ¹⁸O values, the Mg/Ca and Sr/Ca ratios, and the high radiogenic values of the calcite cements formed during this period indicate precipitation from meteoric waters. The results of this study have implications for carbonate hydrocarbon reservoir analogs subject to karstic influence in the Valencia Trough and elsewhere.