URANIUM‐SERIES AND LUMINESCENCE DATING OF VOLCANIC LITHIC ARTEFACTS*

U‐series dating was used to determine the growth rate of a feldspar‐to‐clay weathering rind in a mid‐Holocene Cascade–Olcott tradition andesite core, and luminescence dating (last exposure to sunlight) was used to date fine‐grained feldspars scraped from the surfaces of similar buried artefacts from a ¹⁴C‐sediment‐dated archaeological site (45KI464) on the wet western slope of the Cascade Mountains of Washington. For U‐series dating, we measured ²²⁶Ra excess (²²⁶Ra excess =²²⁶Ra –²³⁰Th) in five stratigraphic depth controlled rind scrapings. ²³⁸U, ²³²Th and ²³⁰Th were counted by alpha spectrometry, and ²²⁶Ra and ²¹⁰Pb were counted by gamma spectrometry on each sub‐sample.     

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.     

Significance and Limitations of Stable Oxygen Isotope Ratios in the Apatite Phosphate of Archaeological Vertebrate Finds for Provenance Analysis in an Alpine Reference Region

A multi‐isotope fingerprint consisting of δ¹⁸O_phosphate, ⁸⁷Sr/⁸⁶Sr, ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁸Pb/²⁰⁷Pb and ²⁰⁶Pb/²⁰⁷Pb was established in the bioapatite of 219 individual archaeofaunal remains (cattle, pig, red deer) excavated from sites located along a specific transect of the European Alps, namely the Inn–Eisack–Adige–Brenner Passage, that has been of eminent importance since European prehistory. This reference area is vertically stratified, and since δ¹⁸O in the skeleton is influenced by climate, water source, physiology and even culture, we tested the relative contribution and importance of δ¹⁸O as a component of the multi‐isotope fingerprint for provenance analysis in this alpine region by a novel mathematical approach. In particular, we adapted a supervised learning approach through expectation–maximization (EM) clustering for fingerprint extraction and evaluated the contribution of each isotopic ratio to the data structure. While an altitude effect was evident in δ¹⁸O, its overall structural importance in the complete isotopic fingerprint was rather low. Therefore, provenance analysis of bioarchaeological finds in this region is possible by measuring stable Sr and Pb ratios alone, which is of considerable importance when δ¹⁸O values are not available, e.g., in cremated finds, although some information is lost. Whether this is tolerable depends on the scientific question to be solved.     

Constraining groundwater flow in the glacial drift and saginaw aquifers in the Michigan Basin through helium concentrations and isotopic ratios

³He and ⁴He concentrations in excess of those in water in solubility equilibrium with the atmosphere by up to two and three orders of magnitude are observed in the shallow Glacial Drift and Saginaw aquifers in the Michigan Basin. A simplified He transport model shows that in situ production is negligible and that most He excesses have a source external to the aquifer. Simulated results show that ³He and ⁴He fluxes entering the bottom of the Saginaw aquifer are 7.5 × 10^?14 and 6.1 × 10^?7 cm³STPcm^?2 yr^?1, both of which are lower than fluxes entering the underlying Marshall aquifer, 1.0 × 10^?13 and 1.6 × 10^?6 cm³STPcm^?2 yr^?1 for ³He and ⁴He, respectively. In contrast, He fluxes entering the Saginaw aquifer are higher than fluxes entering the overlying Glacial Drift aquifer of 5.2 × 10^?14 and 1.5 × 10^?7 cm³STPcm^?2 yr^?1 for ³He and ⁴He, respectively. The unusually high He fluxes and their decreasing values from the lower Marshall to the upper Glacial Drift aquifer strongly suggest the presence of an upward cross‐formational flow, with increasing He dilution toward the surface by recharge water. These fluxes are either comparable to or far greater than He fluxes in deeper aquifers around the world. Model simulations also suggest an exponential decrease in the horizontal groundwater velocity with recharge distance. Horizontal velocities vary from 13 to 2 myr^?1 for the Saginaw aquifer and from 18 to 6 myr^?1 for the Marshall aquifer. The highly permeable Glacial Drift aquifer displays a greater velocity range, from 250 to 5 myr^?1. While Saginaw ⁴He ages estimated based on the simulated velocity field display an overall agreement with ¹⁴C ages, ¹⁴C and ⁴He ages in the Glacial Drift and Marshall aquifers deviate significantly, possibly due to simplifications introduced in the He transport model leading to calculation of first‐order approximation He ages and high uncertainties in Glacial Drift ¹⁴C ages.     

Sediment geochronology and spatio-temporal and vertical distributions of radionuclides in the Upper Bonny Estuary (South Nigeria)

Surface deposits and sediment cores were collected from the Upper Bonny Estuary, located in Southwest Nigeria, and analyzed to determine spatio-temporal and vertical distributions of radio-nuclide activities expressed in Bq·kg^?1 dry weight. The results of activities of naturally occurring radionuclides of ²²⁶Ra (15 ± 2–34 ± 3 Bq·kg^?1), ²²⁸Ra (32 ± 5–48 ± 6 Bq·kg^?1), ⁴⁰K (264 ± 29–462 ± 36 Bq·kg^?1) were found to be all within the range of typical values reported for coastal regions. Ratios of ²²⁶Ra to ²²⁸Ra suggested accretion for all samples with low sediment accumulation registered during rainy months. In addition, vertical distributions at the three sampling sites were also studied with the initial aim of establishing chronologies from the decay of excess ²¹⁰Pb. In two cores, excess ²¹⁰Pb, estimated by subtracting ²²⁶Ra from total ²¹⁰Pb on a layer-by-layer basis, exhibit relatively constant activity with discrete minima and maxima. Therefore, these cores were excluded from radiometric dating. Only the third core could be dated by the constant rate of supply model, and ¹³⁷Cs was utilized to validate the ²¹⁰Pb chronology.     

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.     

Sedimentation rates in the Lake Qattinah using 210Pb and 137Cs as geochronometer

The constant rate of supply (CRS) of excess ²¹⁰Pb model was successfully applied to assess ²¹⁰Pb data of two sediment cores from the lake Qattinah, Syria. Gamma spectrometry was used to determine ¹³⁷Cs and ²¹⁰Pb activity concentrations. The bottom of the cores was ²¹⁰Pb-dated to years 1907 and 1893. The accumulation rates were determined using ²¹⁰Pb method and found to vary similarly in both cores from 0.10 ± 0.01 to 3.78 ± 0.57 kg m^?2 y^?1 during the past century. ¹³⁷Cs was used as an in-dependent chronometer. The two distinct peaks observed on the ¹³⁷Cs record of both cores, corresponding to 1965 and 1986, have allowed a successful validation of the CRS model.     

A LEAD ISOTOPE DATABASE: THE LOS PEDROCHES – ALCUDIA AREA (SPAIN); IMPLICATIONS FOR ARCHAEOMETALLURGICAL CONNECTIONS ACROSS SOUTHWESTERN AND SOUTHEASTERN IBERIA*

One hundred and twenty‐five new lead isotopic analyses on galena, mainly from the Los Pedroches – Alcudia Valley area of southern Iberia, are presented. These data allow us to define four compositional groups in the ²⁰⁷Pb/²⁰⁶Pb versus ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁷Pb/²⁰⁶Pb versus ²⁰⁶Pb/²⁰⁴Pb diagrams. Group I compositions are intermediate between those previously reported for southeastern and southwestern Iberian ore mineral locations. The compositions of Group II, the largest group, overlap with ore data from southwestern Spain. Groups III and IV have compositions that have never before been identified in this region and are comparable to those from the Sardinian Cu ores, which might explain the previously assumed exotic origin for local Bronze Age artefacts.     

Geochemical fingerprinting of hydraulic fracturing fluids from Qusaiba Hot Shale and formation water from Paleozoic petroleum systems,Saudi Arabia

Provenance studies of produced water are essential to trace flow dynamics and reservoir compartmentalization in petroleum systems and to quantify fluid recovery rates from unconventional fracturing. Produced water from a hydraulically fractured well in the Qusaiba Hot Shale in the Northern Exploration Area, Saudi Arabia, was daily monitored and analyzed for water chemistry, and environmental (δ²H, δ¹³C, δ¹⁸O_H2O, δ¹⁸O_SO4, δ³⁴S_SO4, δ³⁷Cl, ⁸⁷Sr/⁸⁶Sr) and cosmogenic isotopes (³H, ¹⁴C, ³⁶Cl), to differentiate from reference fluids of supply water, fracturing fluids, and formation water from adjacent Paleozoic units. Initially, recovered water is composed of fracturing fluids and subsequently replaced by a homogeneous cut of pristine formation water. Formation water is composed of dominant meteoric water (approximately 84 vol%) and minor fossil evaporated seawater. The young ¹⁴C‐apparent age between 6000 and 6700 years BP and depleted δ¹⁸O/δ²H values for the meteoric component confirm the infiltration of surface water into the Qusaiba Hot Shale interval or adjacent units during the Early Holocene Pluvial Period under cooler and wetter climatic conditions than present, which suggest the presence of a very recent, dynamic hydraulic flow system. ³⁶Cl/Cl ratios between 102 × 10^?15 and 31 × 10^?15 are ambiguous and can be attributed to atmospheric recharge close to the coast, mixing of ³⁶Cl‐enriched Quaternary meteoric recharge with ³⁶Cl‐depleted fossil seawater, and/or hypogene production by U‐Th‐enriched host rock. Produced waters from Qusaiba Hot Shale are within the compositional range of Na‐Cl‐type formation water from Paleozoic reservoir units in northern Saudi Arabia with salinities from 30 000 to 130 000 mg l^?1. As a novel technological approach for exploration wells in Northern Saudi Arabia, multi‐isotopic methods were successfully implemented to quantify flowback volumes from hydraulic fracturing, and to fingerprint pristine formation water or pore water in Paleozoic systems on their provenance, residence time, migration pathways, and secondary alteration processes.     

THE PROVENANCE AND TECHNOLOGY OF NEAR EASTERN GLASS: OXYGEN ISOTOPES BY LASER FLUORINATION AS A COMPLEMENT TO STRONTIUM*

The ability to make rapid measurements on small samples using laser fluorination enhances the potential of oxygen isotopes in the investigation of early inorganic materials and technologies. δ¹⁸O and ⁸⁷Sr/⁸⁶Sr values are presented for glass from two primary production sites, four secondary production sites and a consumer site in the Near East, dating from Late Antiquity to the medieval period. δ¹⁸O is in general slightly less effective than ⁸⁷Sr/⁸⁶Sr in discriminating between sources, as the spread of measured values from a single source is somewhat broader relative to the available range. However, while ⁸⁷Sr/⁸⁶Sr is derived predominantly from either the lime‐bearing fraction of the glass‐making sand or the plant ash used as a source of alkali, δ¹⁸O derives mainly from the silica. Thus the two measurements can provide complementary information. A comparison of δ¹⁸O for late Roman – Islamic glasses made on the coast of Syria–Palestine with those of previously analysed glasses from Roman Europe suggests that the European glasses are relatively enriched in ¹⁸O. This appears to contradict the view that most Roman glass was made using Levantine sand and possible interpretations are discussed.     

A comparative study of H+ and He+ at sunspot minimum and sunspot maximum

The time-dependent equations of continuity and momentum for O⁺, H⁺ and He⁺ are solved for the section of a mid-latitude flux tube from the lower F2-region to the equator. H⁺ and He⁺ behaviour is compared for both sunspot minimum and sunspot maximum conditions at equinox concentrating on light ion replenishment following a magnetic storm and light ion fluxes.It is found that the He⁺ fluxes vary little from day to day throughout the replenishment period following a magnetic storm. In contrast, the H⁺ fluxes can vary considerably throughout the replenishment period, particularly at sunspot minimum. In addition, our results show that temperatures above 1000 km have an important influence on the variation and magnitude of H⁺ fluxes and consequently also influence the replenishment of H⁺. At sunspot minimum the He⁺ content reaches its maximum value after eight days of replenishment and then starts to decrease whilst the H⁺ content continues increasing. This is explained in terms of night-time H⁺ return flows dragging the He⁺ to regions where it can readily recombine. Consequently lightion depletion following a magnetic storm provides a loss process for neutral helium at sunspot maximum but not necessarily at sunspot minimum.     

The use of radiocarbon-derived ΔC as a paleoclimate indicator: applications in the Lower Alentejo of Portugal

Values of δ¹³C are frequently reported with radiocarbon dates from organic materials. In C₃ plants δ¹³C values have been linked to changes in water use efficiency as a response to arid conditions. By calculating ¹³C discrimination (Δ¹³C) from ¹³C isotopic composition (δ¹³C), archaeologists can gain potentially valuable inference into past climate conditions. Values of Δ¹³C reflect the process of discrimination against heavier ¹³C isotopes of carbon by comparing the δ¹³C of samples to that of the atmosphere, and can be calculated when records of atmospheric δ¹³CO₂ are available. The present study examines a 1300 year history of radiocarbon-derived Δ¹³C from the Lower Alentejo of Portugal using charcoal recovered from excavations of a series of medieval habitation sites in the study area. To calculate Δ¹³C, the posterior means generated from Bayesian change-point analysis of δ¹³CO₂ records were used. Archaeological data were then compared to contemporary ecological studies of Δ¹³C of the same taxa against instrumental records of climate. Values of Δ¹³C fell within mean ranges for the taxa through a period of population growth between the 7th and 10th centuries AD. During the height of the Medieval Warm Period in the 11th century AD Δ¹³C values frequently fell to low levels associated with arid conditions. At this time environmental degradation and erosion were documented. Values of Δ¹³C increased for a brief period in the early 12th century AD before the rural Lower Alentejo was largely abandoned for nearly two centuries. Another period of aridity occurred in the 16th and 17th centuries AD. Radiocarbon-derived Δ¹³C is a potentially useful paleoclimate proxy for archaeologists provided that results can be paired with observed Δ¹³C variation in studies that pair these data with instrumental climate records.     

CARBON AND OXYGEN ISOTOPE RATIOS OF MARBLES FROM SOME ANCIENT QUARRIES OF WESTERN ANATOLIA AND THEIR ARCHAEOLOGICAL SIGNIFICANCE

¹³C/¹²C and ¹⁸O/¹⁶O ratios have been measured for 42 marbles from the main quarry localities of archaeological interest of Western Anatolia (Marmara, Ephesos, Aphrodisias, Denizli and Afyon) in order to test the possibility of isotopically characterizing ancient marbles from this region. The various groups of samples are not clearly distinguishable on a δ¹³C-δ¹⁸O diagram. However, if only white or slightly coloured samples are considered, the isotopic method appears to be much more selective.     

Residence times and source ages of deep crustal fluids: interpretation of 129I and 36Cl results from the KTB‐VB drill site,Germany

We present here ¹²⁹I/I and ³⁶Cl/Cl ratios, together with halogen concentrations in crustal fluids from the continental deep drill site (KTB‐VB) in Germany, where fluids were collected from 4000 m depth during a pump test carried out in 2002 and 2003. Compared with seawater, the fluids are enriched by factors of 2, 8 and 40 for Cl^?, Br and I, respectively, and show little variation over the test period. The ¹²⁹I/I ratios are between 1700 and 4100 × 10^?15; the ³⁶Cl/Cl ratios are below 10 × 10^?15. Co‐variation between ¹²⁹I and ³⁶Cl concentrations in the fluids indicates that anthropogenic components are absent and that the ratios reflect an addition from crustal sources. The results suggest residence times of 10 Ma or more for the fluids in formations with uranium concentrations of 1 ppm. A minimum age of 30 Ma for the iodine source was derived from the correlation between ¹²⁹I and ³⁶Cl concentrations in the fluids. The results demonstrate that the halogen characteristics of the KTB fluids are very similar to those of other deep crustal fluids and that the combination of ¹²⁹I and ³⁶Cl systematics allows determination of residence times and source ages of such fluids.     

Horticulturists and oxygen ecozones in the tropical and subtropical forests of Southeast South America

We analyse the isotopic values (δ¹³C, δ¹⁵N) of the diet of pre-Columbian horticulturalist populations from tropical and subtropical areas of southeastern South America, belonging to the Guarani and Taquara archaeological units. The data indicate different trends in each one (T?=?4.21; P?=?0.0004), showing a mixed diet with maize consumption in the Guarani samples (δ¹³C_co?=??15.5?±?1.8‰; δ¹³C_ap ?10.4?±?0.8‰) and a depleted one in the Taquara ones (δ¹³C_co ?18.2?±?1.7‰; δ¹³C_ap ?11.9?±?0.9‰), with a significant internal dispersion in both populations. The first population has higher nitrogen values (δ¹⁵N 11.1?±?0.6‰) compared to the Taquara samples (δ¹⁵N 9.3?±?1‰), suggesting a more carnivorous diet. The recognition of these pre-Columbian mixed diets involves the identification of maize cultivation on the Atlantic side of the southernmost area of South America (Parana Delta, 34° SL). Through the analysis of δ¹⁸O we have identified two isotopic ecozones, the first along the Paraná River Valley, with an average value of δ¹⁸O ?3.7?±?0.5‰ (CV?=?13.5%; CI?=??3.83 / ?3.16), and the second one, located in the Planalto of southern Brazil (Araucaria Forest), with a mean value of δ¹⁸O ?1.5?±?0.3‰ (CV?=?16.5%; CI?=??1.69 / ?1.29). The isotopic data (δ¹³C, δ¹⁵N and δ¹⁸O) suggest human movements between these two ecozones.     

The effects of differential ion flows on EISCAT observations in the auroral ionosphere

During geomagnetic storms different partial pressure gradients in the auroral ionosphere may result in H⁺, He⁺, O⁺ and molecular ions drifting with different velocities along the Earth's magnetic field line. For relative drift velocities ⪡ 400 m s⁻¹ it is shown that differential ion flows may be identified by two signatures in the autocorrelation function (ACF) measured by EISCAT. For larger relative drifts numerical simulations show that these signatures still exist and may result in an asymmetry in the incoherent scatter spectrum for O⁺ and molecular ions. It is demonstrated that UHF data can be reliably analysed for k²λ_D² ≲ 1, but at high altitudes, where O⁺–H⁺ flows are expected, UHF observations will be restricted by large Debye lengths (k²λ_D² > 1). Examples of ACFs based on polar wind theory are presented and discussed for the VHF system and finally it is shown that large ion temperature ratios (T_i(H⁺) >T_i(O⁺)) can significantly affect the velocity determination.     

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.     

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.     

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.     

Diet and death in times of war: isotopic and osteological analysis of mummified human remains from southern Mongolia

This study presents the results of an isotopic analysis of nine naturally mummified individuals—three adults, two adolescents, one juvenile, and three infants—recovered from the Hets Mountain Cave site in southern Mongolia, where they had been secondarily deposited. All of the individuals show evidence of violent perimortem trauma, but no skeletal indicators of nutritional or disease-related stress. Multi-isotopic data (δ¹³C, δ¹⁵N, δ¹⁸O, ⁸⁷Sr/⁸⁶Sr, and ²⁰ⁿPb/²⁰⁴Pb) were characterized in multiple tissues from each individual when possible, in order to reconstruct diet composition and residential origin at different points in life. Specifically, δ¹³C and δ¹⁵N in bone carbonate and collagen (N = 8) and hair keratin (N = 4) were coupled with enamel carbonate δ¹⁸O and δ¹³C (N = 3) and enamel ⁸⁷Sr/⁸⁶Sr, and ²⁰ⁿPb/²⁰⁴Pb (N = 3) to assess diet and residential mobility in relation to skeletal indicators of health and trauma. Results are consistent with a persistence of mixed C₃/C₄ pastoral subsistence and general stability of diet composition over the life course, in contrast to contemporary accounts of widespread famine and a dependence on grains imported from China throughout the region. However, results also suggest that at least some individuals may have migrated to this region of southern Mongolia from elsewhere during life, meaning that their dietary isotopic profiles may not represent local subsistence patterns near the Hets Mountain Cave site. Overall, these results speak to the utility of life course oriented multi-isotopic analysis in complementing more top-down historical analyses in understanding variation in subsistence, nutrition, and migration in regions undergoing significant political and economic turmoil.