Reduced Population Variance in Strontium Isotope Ratios Informs Domesticated Turkey Use at Chaco Canyon,New Mexico,USA

Traditionally, strontium isotopes (⁸⁷Sr/⁸⁶Sr) have been used as a sourcing tool in numerous archaeological artifact classes. The research presented here demonstrates that ⁸⁷Sr/⁸⁶Sr_bioapatite ratios also can be used at a population level to investigate the presence of domesticated animals and methods of management. The proposed methodology combines ecology, isotope geochemistry, and behavioral ecology to assess the presence and nature of turkey (Meleagris gallopavo) domestication. This case study utilizes ⁸⁷Sr/⁸⁶Sr_bioapatite ratios from teeth and bones of archaeological turkey, deer (Odocoileus sp.), lagomorph (Lepus sp. and Sylvilagus sp.), and prairie dog (Cynomys sp.) from Chaco Canyon, NM, USA (ca. A.D. 800–1250). Wild deer and turkey from the southwestern USA have much larger home ranges and dispersal behaviors (measured in kilometers) when compared to lagomorphs and prairie dogs (measured in meters). Hunted deer and wild turkey from archaeological contexts at Chaco Canyon are expected to have a higher variance in their ⁸⁷Sr/⁸⁶Sr_bioapatite ratios, when compared to small range taxa (lagomorphs and prairie dogs). Contrary to this expectation, ⁸⁷Sr/⁸⁶Sr_bioapatite values of turkey bones from Chacoan assemblages have a much lower variance than deer and are similar to that of smaller mammals. The sampled turkey values show variability most similar to lagomorphs and prairie dogs, suggesting the turkeys from Chaco Canyon were consuming a uniform diet and/or were constrained within a limited home range, indicating at least proto-domestication. The population approach has wide applicability for evaluating the presence and nature of domestication when combined with paleoecology and behavioral ecology in a variety of animals and environments.     

Reconstructing ancient Maya animal trade through strontium isotope (87Sr/86Sr) analysis

This study explores the potential for using strontium isotope analysis (⁸⁷Sr/⁸⁶Sr) to study ancient Maya animal exchange. Traditional zooarchaeological methods of studying trade rely on the identification of animals found outside their natural geographic or habitat ranges. Isotopic analysis provides an additional means of identifying and sourcing non-local animals. ⁸⁷Sr/⁸⁶Sr values from Maya zooarchaeological remains indicate that regional and long-distance transport and exchange of animal goods was more common than previously recognized. Widely distributed animals including deer and peccary were among the animals exchanged, which questions their common interpretation as locally-acquired resources. The isotopic results contribute to our understanding of how animal products were integrated into Maya economic and exchange networks. The research is also relevant to human mobility studies in Mesoamerica.     

Revisiting the potential of carbonized grain to preserve biogenic 87Sr/86Sr signatures within the burial environment

Strontium (Sr) isotope analysis of archaeological crops is a potential method of provenancing and identifying the movement of crops in the past, but there remains uncertainty about whether original ⁸⁷Sr/⁸⁶Sr values can be obtained from carbonized buried grains. We have determined that hydrochloric acid (HCl) leaching removes some, but not all, exogenous Sr from carbonized cereal grains buried in soil for up to one year. We conclude that while further work could refine the leaching method, Sr isotope analysis of archaeological cereal grains can distinguish crops sourced from outside a particular (e.g., local) area if it can be shown that leaching moves grain ⁸⁷Sr/⁸⁶Sr values significantly away from the expected Sr signature.     

CHEMICAL COMPARISON OF RARE CHINESE WHITE POTTERY FROM FOUR SITES OF THE ERLITOU STATE: RESULTS AND ARCHAEOMETRICAL IMPLICATIONS

White pottery is among the most significant finds from China's earliest state, Erlitou (c. 1900–1500 bc ). Samples were primarily discovered in small numbers from elite tombs of a few sites, leading to the hypothesis that they were made at only a few locations and then circulated regionally as prestige items. To facilitate determining provenances, we compare the ICP–MS trace elements and TIMS Sr isotopes of whiteware with two soil samples from Nanwa, a possible manufacturing site, and with shards found at three other sites: Erlitou, Huizui and Nanzhai. The Nanwa shards demonstrate special elemental and Sr isotopic features. Considering the chemical observation and archaeological background together, we propose that Nanwa was a centre for whiteware production, although the two soil samples we collected there were probably not the exact materials used. Some whiteware pieces from Erlitou, Huizui and Nanzhai fall in the chemical field defined by Nanwa samples, indicating that they were possibly made at Nanwa. Many other samples from these three sites plot outside the Nanwa field, implying they were probably not Nanwa products. This study demonstrates that while chemical sourcing is very useful, firm archaeological context must remain the cornerstone of such research.     

Identifying immigrants to Tikal,Guatemala: Defining local variability in strontium isotope ratios of human tooth enamel

Stable strontium isotopes have been used to identify the skeletons of migrants in several recent archaeological studies, in which local ⁸⁷Sr/⁸⁶Sr values have been inferred through statistical parameters of human ⁸⁷Sr/⁸⁶Sr data, or by reference to local fauna or other environmental samples. This paper compares these approaches using data from the ancient Maya city of Tikal, Guatemala. The skeletons of eight migrants from distant geological zones are readily apparent among the 83 Tikal skeletons sampled. Three additional non-local skeletons can be eliminated to obtain a normally distributed “local” Tikal sample. The mean of this sample is higher than the available data for local fauna and for lime that may have been used to treat maize at Tikal. It is possible that imported sea salt with a high ⁸⁷Sr/⁸⁶Sr ratio could account for this elevated mean for Tikal humans. Modeling demonstrates that dietary ⁸⁷Sr/⁸⁶Sr may be raised to the level found at Tikal by a daily intake of only 6 g of sea salt.     

Physical and Geochemical Characteristics of Soils from Angel Mounds State Historic Site,Indiana, including a Case Study of Sherds from Unit A

Abstract

Using physical and chemical characteristics of soil to evaluate archaeological artifacts and their preservation potential along with associated features is well established. The soil characteristics and geochemistry of the Angel Mounds site (12Vg1) indicate the soil geochemistry is very homogenous and composed of loams and silt loams with a range of pH values from 4.69 to 6.17, mean value of 5.40 ± 0.47. The slightly acidic nature of the soil favors the preservation of pollen and soil diatoms, with minor corrosion potential for the bone, shell, and sherd artifacts. A comparison of the geochemistry of the soils from Unit A and site-wide sampling to sherds from Unit A suggests that elevated phosphorus (P) in the sherds is either the result of the addition of a P-rich temper material or from the sourcing of nonlocal clay-rich sediment, and not from use-derived residue or from the soils themselves.     

Oxygen isotopes in cellulose identify source water for archaeological maize in the American Southwest

Maize (Zea mays) was a primary food crop for aboriginal societies of the arid American Southwest. Water used for maize production in these arid zones could have come from precipitation and runoff during the summer monsoon, from perennial streams and springs, or from stored soil water fed by snowmelt. The oxygen stable isotope ratio (δ¹⁸O) of summer and winter precipitation on the Colorado Plateau naturally differ by more than 10‰ providing a powerful tool for distinguishing winter- from summer-derived water sources used in cultivation of maize. We investigated whether variation in δ¹⁸O of potential source waters is preserved in the δ¹⁸O of cellulose (δ¹⁸O_cellulose) of maize cobs by growing four aboriginal and one modern maize variety in pots irrigated with water of known δ¹⁸O composition. The δ¹⁸O_cellulose values of cobs ranged from 26.8 to 36.4‰ (averaged within varieties) and were highly correlated with δ¹⁸O values of the source irrigation water (−15.8 to −8.2‰). Cob δ¹⁸O_cellulose from five archaeological sites on the Colorado Plateau in southeastern Utah ranged from 27.3 to 34.6‰, closely matching the range of values observed in experimental plants. A δ¹⁸O_cellulose model developed originally for tree rings was parameterized and applied to the archaeological maize cobs. The model indicated that monsoonal precipitation accounted for 0–20% of the moisture for archaeological cob samples from a site adjacent to a perennial stream and 43–98% for samples from an upland site, more distant from a perennial water source. These results reveal the potential for using δ¹⁸O_cellulose to investigate prehistoric irrigation practices and source water used for maize production in the American Southwest.     

Strontium isotope analysis of Neolithic and Copper Age populations on the Great Hungarian Plain

The strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) is used in archaeological studies to identify major events of population movement in prehistory such as migration, conquest, and inter-marriage. This study shows that the strontium isotope method can be expanded to identify more subtle shifts in prehistoric human mobility. ⁸⁷Sr/⁸⁶Sr isotope ratios were analyzed in dental enamel from human and faunal specimens from the Late Neolithic and Copper Age on the Great Hungarian Plain. The archaeological record indicates that several aspects of life changed during the transition from the Late Neolithic to the Copper Age (ca. 4500 BC) in Hungary; evidence for increased interaction over a wide geographical area, less resource pooling and the use of secondary products has been used to support the idea that local populations became more mobile, perhaps due to the adoption of an agro-pastoral economy. Results from this study identify a change in the range of strontium isotope values from the Late Neolithic to the Copper Age from a very narrow range of values to a much broader range of values, which suggests that changes in how land and resources were utilized on the Great Hungarian Plain affected incorporation of strontium into the skeletal system. This study indicates that the strontium isotope ratio is a valuable tool for identifying more subtle changes in prehistoric behavior such as a shift to a more pastoral economy.     

Baseline data for Andean paleomobility research: a radiogenic strontium isotope study of modern Peruvian agricultural soils

While the use of radiogenic strontium isotope values to examine paleomobility is increasingly common in the Andes, and beyond, many questions about baseline variability remain. To better understand baseline radiogenic strontium isotope compositions in the Andes, we present new ⁸⁷Sr/⁸⁶Sr values from Peruvian soil samples. Modern soil samples were collected from agricultural fields from the following areas in central and southern Peru: Arequipa, Atico, Camaná, Chala, Cusco, Ica, Ilo, Lima, Mejía, Moquegua, Nazca, Ocoña, Palpa, Pisco, Puno, Tacna, and Yauca. Samples were partially dissolved to better approximate the bioavailable strontium. Radiogenic strontium isotope values from the partially dissolved soil samples range from ⁸⁷Sr/⁸⁶Sr?=?0.70202 to 0.71894 and, for all soil samples, have a mean of ⁸⁷Sr/⁸⁶Sr?=?0.70773?±?0.00166 (1σ, n?=?114). In general, the ⁸⁷Sr/⁸⁶Sr values measured for soil samples collected from modern agricultural fields reflect the expected ⁸⁷Sr/⁸⁶Sr values based on bedrock geology. Comparing our new soil data with published radiogenic strontium isotope data for bedrock, soil, water, and faunal samples provides constraints on the regions in the Andes that can, and cannot, be distinguished through radiogenic strontium isotope analysis.     

Baseline bioavailable strontium isotope values for the investigation of residential mobility and resource-acquisition strategies in prehistoric Cambodia

Strontium (Sr) isotope ratios (⁸⁷Sr/⁸⁶Sr) measured in human skeletal material can increase one's understanding of the residential behaviour and resource-acquisition strategies of past populations. The paper maps bioavailable ⁸⁷Sr/⁸⁶Sr variation in 183 plant and soil samples across Cambodia. Bioavailable ⁸⁷Sr/⁸⁶Sr, as measured in plants, differs significantly between four major geological units. The data set will support future investigations of skeletal material from Cambodian archaeological sites. Baseline ⁸⁷Sr/⁸⁶Sr data should be applied judiciously to skeletal populations, and in concert with other lines of evidence, to identify potential geographical outliers rather than to ascribe specific locations from which individuals may have moved.     

Development and application of methods used to source prehistoric Southwestern maize: a review

Archaeological cobs free of mineral contaminants should be used to source the soils in which they were grown. Mineral contaminants often contain much higher concentrations of metals than vegetal materials and can alter a cob’s apparent metal and heavy-isotope content. Cleaning a cob via immersion in an acid solution for more than a few minutes will result in the incongruent and sometimes complete leaching of metals, including strontium (Sr), from the cob. When using ⁸⁷Sr/⁸⁶Sr to determine the location of potential agriculture fields, it is best to either integrate several depth-integrated soil samples or to integrate several vegetation samples from individual fields. Biologically labile Sr in semi-arid Southwestern soils largely originates from eolian source or sources and usually is not derived from underlying bedrock. Existing Sr-isotope data indicate that archaeological cobs from Aztec Ruins came from either the Mesa Verde-McElmo Dome or Totah areas, that Pueblo Bonito and Chetro Ketl cobs, from Chaco Canyon that predate A.D. 1130, probably came from the Rio Chaco corridor, and that cobs from Chaco Canyon, that postdate A.D. 1130, probably came from either the Totah or Zuni areas.     

AN ASSESSMENT OF THE CURRENT APPLICATIONS AND FUTURE DIRECTIONS OF OBSIDIAN SOURCING STUDIES IN ARCHAEOLOGICAL RESEARCH*

This paper thematically characterizes a large body of recent obsidian sourcing discourse as a means of highlighting the current place of obsidian provenance studies in larger archaeological discourse. It is shown that the field of obsidian sourcing is flourishing, with a clear upward trend in the number of published studies in the past decade. This paper further argues that sourcing is a means to an end, a way to determine where artefacts originate, and thus a means of addressing broader archaeological problems. Through this contextual framework, obsidian sourcing studies—and indeed all provenance studies—are seen as relevant because they transcend the increasingly specialized world of archaeological discourse.     

Isotopic values of diet of Blastocerus dichotomus (marsh deer) in Paraná Basin,South America

The marsh deer (Blastocerus dichotomus, Illiger, 1815) is the largest contemporary South American deer, and its habitat includes the floodplains and wetlands of eastern South America. Throughout the Holocene these deer were widely used by indigenous societies, from the southern banks of the Amazon River to the Río de la Plata River, and from the Andean foothills to the Atlantic Ocean. However, despite the enormous ecological and archaeological importance of this ungulate in the region, our knowledge of the isotopic values of their diet is almost nonexistent. This paper is the first systematic approach to the study of the isotopic values of this mammal's diet, using archaeological and present-day samples from interconnected watersheds of the Paraná and Uruguay rivers in east-central Argentina. The results obtained from 24 measurements indicate an average value of ?21.09 ± 1.46‰ in δ¹³C collagen, with a low coefficient of variation (6.92%). The data indicate a marked preference for consumption of plants with a C₃ photosynthetic pathway. Most of the observed variability in the isotopic values corresponds to the period 900–1430 ¹⁴C years BP, a time range during which the values show higher consumption of C₄ plants. This it could be related with a period where temperature and associated humidity increased, synchronous in the area with the Medieval Climate Anomaly.     

Contribution of strontium to the human diet from querns and millstones: an experiment in digestive strontium isotope uptake

The question of whether rock grit ingested unintentionally from querns, metates or millstones, or deliberately through pica or geophagy, is bioaccessible in the human gut has not been addressed in archaeological strontium (Sr) isotope studies. This study employed the unified bioaccessibility method and determined that ingested rock grit can provide bioaccessible ⁸⁷Sr/⁸⁶Sr, but that unintentional consumption is unlikely to constitute > 1% of the diet (by mass) and will not significantly change, that is, by > 0.001, human skeletal ⁸⁷Sr/⁸⁶Sr. The use of locally or non‐locally sourced querns or millstones will not affect the interpretation of archaeological human ⁸⁷Sr/⁸⁶Sr values in Britain.     

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.     

Prehistoric migration at Nebira, South Coast of Papua New Guinea: New insights into interaction using isotope and trace element concentration analyses

Migration is a commonly used explanation for cultural change in world prehistory, and is also a central theme in the prehistory of the Pacific Islands. However it is rarely subject to direct archaeological research. This paper applies strontium and oxygen radiogenic/stable isotope (⁸⁷Sr/⁸⁶Sr, δ¹⁸O), and trace element concentration (Ba/Sr) analyses to 27 individuals buried at the archaeological site of Nebira (ca.720–300 BP), located inland on the South Coast of Papua New Guinea. The analyses seek to identify non-local individuals within the population and provide a more in-depth understanding about the social identity of the possible migrants in this community.The strontium isotope data indicates that five individuals were non-local to Nebira, having possibly come from a coastal location. Correlation with biological data, such as age and sex, also indicates that the pattern of migration at Nebira was not sex or age specific. The results support the archaeological findings that suggest the inhabitants from Nebira were in contact with coastal communities during a period in prehistory of increased cultural interaction. However, despite the considerable isotopic variation identified in the Nebira sample, it is also demonstrated that more research is needed to identify the possible origins of these non-local individuals.     

Multi-element soil analysis: an assessment of its potential as an aid to archaeological interpretation

Multi-element soil analysis is now an established technique in archaeology. It has been used to locate archaeological sites and define the extent of human activity beyond the structural remains, and to aid interpretation of space use in and around archaeological remains. This study aimed to evaluate the consistency of these soil element signatures between sites and hence their potential usefulness in archaeological studies. Known contexts on abandoned farms across the UK were sampled to test the relationships between element concentrations and known functional area and to assess inter-site variability. The results clearly show that there are significant differences in the soil chemistry of contrasting functional areas, particularly for Ba, Ca, P, Zn, Cu, Sr and Pb. Despite significant site specific effects, which appear to reflect individual anthropogenic practices rather than geological influences, there is sufficient similarity in the pattern of element enhancement to allow reliable interpretation of former function using discriminant models. Relating these enhancements to precise soil inputs, however, is more problematic because many important soil inputs do not contain distinct element fingerprints and because there is mixing of materials within the soil. There is also a suggestion that charcoal and bone play an important role in both the loading and post-depositional retention of Ca, Sr, P, Zn, and Cu and thus may be significant in the formation of soil element concentration patterns.     

Migration in the Nile Valley during the New Kingdom period: a preliminary strontium isotope study

The value of strontium isotope analysis in identifying immigrants at numerous archaeological sites and regional areas has been demonstrated by several researchers, usually by comparing ⁸⁷Sr/⁸⁶Sr values of human tooth enamel and/or bone with the local strontium isotope signature determined by faunal and environmental samples. This paper examines the feasibility of using ⁸⁷Sr/⁸⁶Sr ratios to investigate residential mobility in the Nile Valley region, specifically at the New Kingdom period (∼1050–1400 BC) archaeological site of Tombos (ancient Nubia). Archaeological and textual information regarding this period indicates that immigrant Egyptians and local native Nubians were likely interacting at this site during a period of Egyptian colonial occupation. The results of this study suggest that non-local individuals may be distinguished from locals using ⁸⁷Sr/⁸⁶Sr values and that colonial agents in the Tombos population were probably both local native Nubians and immigrants.     

Strontium isotopes and human mobility in prehistoric Denmark

The principles behind the strontium isotopic system are an important tool for archaeologists tracing human migration and patterns of movement in prehistory. However, there are several scientific challenges of analytical nature, as well as those which relate to unknown parameters inherent to the interpretation of such data. One prerequisite is the knowledge of the range of strontium isotopic ratios that best characterize the bioavailable fractions of a particular area of interest. The study reported here attempts to establish a baseline for strontium isotope signatures valuable for Denmark (excluding the island of Bornholm) and particularly for the use in archaeological investigations. We present strontium isotope ratios of bones and teeth from modern mice contained in owl pellets, of snail shells, and of archaeological fauna samples. We compare these ratios with median strontium isotope signatures characterizing human enamel populations from archaeological sites within Denmark. The fauna samples reported here range from ⁸⁷Sr/⁸⁶Sr = 0.70717 to 0.71185 with an average of 0.70919, and human enamel defines a range from ⁸⁷Sr/⁸⁶Sr = 0.7086 to 0.7110 with an average of 0.7098. In both datasets, we observe a small difference between the baseline values for the western (Jutland) and eastern (Funen, Zealand, and the southern islands) parts of Denmark. We therefore propose two slightly different baseline ranges with a partial overlap for the isotopic signatures of bioavailable strontium fractions within Denmark, namely a range of ⁸⁷Sr/⁸⁶Sr = 0.7078–0.7098 for the western area and a range of ⁸⁷Sr/⁸⁶Sr = 0.7089–0.7108 for the eastern parts.     

Strontium isotope analysis and human mobility during the Neolithic and Copper Age: a case study from the Great Hungarian Plain

From the Late Neolithic to the Early Copper Age on the Great Hungarian Plain (4500 BC, calibrated) a transformation in many aspects of life has been inferred from the archaeological record. This transition is characterized by changes in settlements, subsistence, cultural assemblages, mortuary customs, and trade networks. Some researchers suggest that changes in material culture, particularly the replacement of long-occupied tells with smaller, more dispersed hamlets, indicates a shift from sedentary farming villages to a more mobile, agropastoral society that emphasized animal husbandry and perhaps secondary products of domestication. In a previous study (Giblin, 2009), preliminary radiogenic strontium (⁸⁷Sr/⁸⁶Sr) isotope data from human dental enamel showed that Copper Age individuals expressed more variable isotope values than their Neolithic predecessors. These data provided support for the idea that Copper Age inhabitants of the Plain were acquiring resources from a greater geographic area, findings that seemed consistent with a more mobile lifestyle. In this article a larger sample from human and animal skeletal material is used to re-evaluate earlier work and shed new light on the transition from the Neolithic to the Copper Age in eastern Hungary. The expanded sample of strontium isotopes from human dental enamel shows that ⁸⁷Sr/⁸⁶Sr values are more variable during the Copper Age, but the change is more pronounced in the Middle Copper Age than in the Early Copper Age. These results, along with recently published complementary research, indicate that the transition from the Late Neolithic tell cultures of the Plain to the more dispersed Copper Age hamlets was more gradual than previously thought, and that the emergence of an agropastoral economy does not explain changes in settlement and material culture.