Strontium Isotope Values Research Articles

Stenopterygiids from the lower Toarcian of Beaujolais and a chemostratigraphic context for ichthyosaur preservation during the Toarcian Oceanic Anoxic Event

Abstract We report new ichthyosaur material excavated in lower Toarcian levels of the LafargeHolcim Val d'Azergues quarry in Beaujolais, SE France. A partially articulated skull and a smaller, unprepared but likely subcomplete skeleton preserved in a carbonate concretion are identified as stenopterygiids, a family of wide European distribution during the Early Jurassic. These specimens are among the finest preserved Toarcian exemplars known from Europe and, in one of them, soft tissue preservation is suspected. Their state of preservation is attributed to the combination of prolonged anoxic conditions near the water–sediment interface and early carbonate cementation resulting from the activity of sulfate-reducing bacteria. We also present carbon and strontium isotope values obtained from the study site that allow detailed temporal comparisons with other Toarcian vertebrate-yielding sites and environmental perturbations associated with the Toarcian Oceanic Anoxic Event (T-OAE). These comparisons suggest that the relatively high abundance and good preservation state of Toarcian vertebrates was favoured by a prolonged period of low bottom water oxygenation and accumulation rates. The environmental conditions that prevailed during the T-OAE were probably responsible for the extensive nature of Lagerstätte-type deposits with exceptional preservation of marine organisms. Testing whether the T-OAE had a biological impact on marine vertebrates requires a precise chemostratigraphic context of the fossil record spanning the Pliensbachian–Toarcian interval.

Carbon, oxygen and strontium isotopes of the Mesoproterozoic Jixian System （1.6-1.4 Ga）in the southern margin of the North China Craton and the geological implications

ABSTRACT The Mesoproterozoic Jixian System (1.6–1.4 Ga) in the Luonan area, southern margin of the North China Craton (NCC), is characterized by complete development, continuous sedimentation and a low degree of structural deformation, resulting in well-preserved palaeontological and paleoenvironmental records. Carbon, oxygen and strontium isotopes of 382 dolostone samples from the Jixian System in Xiong’er Rift, southern margin of the NCC are analysed for the restoration of paleoenvironment and stratigraphic correlation. The results show that the δ13C values of these samples mainly concentrate between −1.8‰ and 2.0‰, and the values can be divided into three segments. The δ18O values are mainly between −6.5‰ and −3.5‰, with frequent fluctuations and weak regularity. The 87Sr/86Sr ratio ranges from 0.7051 to 0.7139, with an average value of 0.7085. Its fluctuations have certain regularity and are negatively correlated with the carbon isotopes, indicating that the sea-level changes during the Jixian period in the southern margin of the NCC. The carbon isotope curve of the samples from the study section is very similar to those of the Xiong’er Rift and the Yanliao Rift of the NCC. The −3.2‰ δ13C negative excursion in the middle and upper parts of the Xunjiansi Formation corresponds to the δ13C negative excursion from the top of the Wumishan Formation to the bottom of the Tieling Formation in the Yanliao Rift. Combined with previous research data, the Jixian System that deposited in the Xiong’er Rift and the Yanliao Rift can be approximately correlated with each other. In addition, the carbon isotope data obtained from this study is comparable to global carbon isotope values during the same period. The rise and oscillation of carbon and strontium isotope values during this period may be a response to the break-up of the Colombian supercontinent.

Individual geographic mobility in a Viking-Age emporium-Burial practices and strontium isotope analyses of Ribe's earliest inhabitants.

Individual geographic mobility is a key social dynamic of early Viking-Age urbanization in Scandinavia. We present the first comprehensive geographic mobility study of Scandinavia’s earliest emporium, Ribe, which emerged around AD 700 in the North Sea region of Denmark. This article presents the results of strontium isotope analyses of 21 individuals buried at Ribe, combined with an in-depth study of the varied cultural affinities reflected by the burial practices. In order to investigate geographic mobility in early life/childhood, we sampled multiple teeth and/or petrous bone of individuals, which yielded a total of 43 strontium isotope analyses. Most individuals yielded strontium isotope values that fell within a relatively narrow range, between 87Sr/86Sr = 0.709 to 0.711. Only two individuals yielded values >87Sr/86Sr = 0.711. This suggests that most of these individuals had local origins but some had cultural affinities beyond present-day Denmark. Our results raise new questions concerning our understanding of the social and cultural dynamics behind the urbanization of Scandinavia.

Population movements of the Huron-Wendat viewed through strontium isotope analysis

Environmental isotopes can provide information about the composition of groups and the movement of people across landscapes. The archaeological record of Huron-Wendat communities in south-central Ontario is one of numerous drainage-based sequences of small villages among which families or larger population segments moved. These villages amalgamated in the early to mid-sixteenth century into fewer, larger communities. Strontium isotope values (87Sr/86Sr) are used to test hypotheses about these early localized interactions and later amalgamations. There is little prior information about strontium values from this region which was recently glaciated and receives ample precipitation. From the late thirteenth century onward, ancestral Huron-Wendat communities had distinct burial practices of primary burial followed by secondary, collective ossuary burial. Strontium values from tooth enamel of 118 human first permanent molars from 15 archaeological contexts spanning four centuries are interpreted in a framework of archaeologically derived deer (N = 34), small (N = 35) and other large (N = 7) mammals. Reflecting their local origins, 87Sr/86Sr values of small mammals from three geological substrates differ significantly from one another. Each small mammal group clusters more tightly than those of deer. Most human 87Sr/86Sr values agree with small mammal values, by region. Three sites, out of six with more than 10 data points, show mean human 87Sr/86Sr values that differ significantly from the small mammal values of their geological substrate, signaling community movement and individual in-migration. Interpretation of individual human values outside local ranges is informed by information from dietary isotopes. Environmental isotopes substantiate and enhance our prior understandings of the ancestral Huron-Wendat.

Neoarchean seafloor hydrothermal metamorphism of basalts in the Zanhuang ophiolitic mélange, North China Craton

Epidosites are suggested to form in up-flow zones located at the base of ore-forming oceanic hydrothermal systems, and are commonly preserved in ophiolitic sequences. However, occurrences of epidosites in Archean tectonic mélanges are rarely documented. In this study, we report the presence of late Neoarchean epidosites in the Zanhuang ophiolitic mélange in the North China Craton using meter-scale litho-structural and petrologic analysis, zircon U-Pb dating, major and trace element, and oxygen and strontium isotopic geochemistry. Field studies show that the epidosites are mainly preserved as the cores of meta-pillow lavas, and are distributed as blocks in different matrices within the tectonic mélange. The pillow rims are used as protolith to estimate the element mobility during the alteration process. The epidosites display strong depletion in Na2O (0.01–0.27 wt%), MgO (0.43–3.01 wt%), depletion in large ion lithophile elements (LILE) (e.g. Rb, Ba, Cs, U) and transition metals (e.g., Co, Sc, Cu, Ni, Zn), and show enrichment of CaO (13.35–21.0 wt%), Sr and Pb. The high field strength elements (HFSE) (e.g. Zr, Hf, Ta, Th) of epidosites are varied but rare earth elements (REE) are unchanged. The amphibolitic pillow rims are characterized by enrichment of LILE, flat heavy rare earth elements (HREE) patterns, and depletion in HFSE with negative Ti anomalies and positive Pb and Ba anomalies. Oxygen and strontium isotopic ratios of epidosites are 5.0–8.6‰ and 0.70284–0.70551, respectively, both of which are greater than those of fresh basalts. The major and trace elements, oxygen and strontium isotopic values and extensive element migration indicate that the protolith was altered by a submarine hydrothermal system in the absence of continental influence. Magmatic zircons from two samples of epidosites yield 207Pb/206Pb ages of 2512 ± 13 Ma (MSWD = 0.51) and 2542 ± 13 Ma (MSWD = 1.4), confirming that the epidosites were generated at ca. 2.51–2.54 Ga. Based on geochemical data and field observations, we suggest that the protolith of the epidosites formed in an arc-related tectonic setting during the late Neoarchean. This study shows that hydrothermal activity operating in the late Neoarchean was similar to that of the modern ocean floor.

New insights from forgotten bog bodies: The potential of bog skeletons for investigating the phenomenon of deposition of human remains in bogs during prehistory

Since the 18 th century, the peat bogs of Northern Europe have yielded the remains of hundreds of people dating from as far back as c. 8.000 BC. While the individuals with preserved soft tissue have been subjected to numerous and comprehensive studies, the less famous bog skeletons have received much less attention, even though the distinction is essentially attributable solely to differences in preservation conditions. The objective of this study is to fill this gap by providing valuable information on ten bog skeletons from the small region of Vesthimmerland in northwest Denmark. The large majority (nine out of ten) of these finds are previously unpublished. We.apply a cross-disciplinary approach consisting of osteological and paleopathological investigations combined with radiocarbon and strontium isotope analyses. Our radiocarbon results show that two of the ten bog skeletons (two adult females) date to the Nordic Neolithic Age, one 8-year old child dates to the Nordic Bronze Age, while the majority are from the Pre-Roman Iron Age and Roman Iron Age (one child, four adult females and two adult males). Anthropological examination suggested no evidence of peri-mortem violence, but the finding of gross pathologies in two individuals could hint at deliberate deposition in the bog. Nine individuals yielded strontium isotopic values suggesting a local origin, whereas a female dating to the Pre- Roman Iron Age yielded highly radiogenic signatures suggesting a non-local origin. These results represent the first cross-disciplinary study of numerous bog skeletons adding much needed information to a neglected group of individuals, shedding new light on the different theories for the deposition of human remains in bogs in prehistoric times.

In Situ Elemental and Sr Isotope Characteristics of Magmatic to Hydrothermal Minerals from the Black Mountain Porphyry Deposit, Baguio District, Philippines

AbstractAt the Black Mountain porphyry Cu-Au deposit in the Baguio district, Northern Luzon (Philippines), pre- and synmineralized rocks preserve magmatic and hydrothermal minerals (e.g., plagioclase, amphibole, titanite, and epidote) spanning the complete paragenesis of the deposit. Strontium isotope values in early crystallized plagioclase phenocrysts from all felsic porphyries can be divided into two types. The type-I plagioclase crystals show relatively homogeneous Sr isotope values (0.7035–0.7038, 1σ <0.0001), indicating crystallization from a relatively stable and long-lived felsic magma chamber. The type-II plagioclase grains have a wider range of Sr isotope compositions (0.7032–0.7039, 1σ <0.0001), indicating mafic and/or felsic magma recharge. In magmatic titanite, Nb/Ta values are higher than those in the whole rock, while Zr/Hf and Y/Ho values are lower. In hydrothermal titanite and epidote, the ratios are similar to those in the whole rock. These patterns reflect crystallization effects imposed during the magmatic stage but an absence of differentiation during the hydrothermal stage. The consistent gradual decrease in total rare earth element, Y, Zr, and U contents in both hydrothermal titanite and epidote from early to late stages indicates the effect of hydrothermal fluid evolution with decreasing temperature. The variation of 87Sr/86Sr values in magmatic amphibole, plagioclase, and hydrothermal epidote in felsic and mafic rocks indicates the addition of mafic magma-derived fluid into the felsic magma-derived fluid. One extra source of fluid (probably derived from wall-rock limestone) was required to generate the highly radiogenic 87Sr/86Sr values of some epidote (0.7038–0.7053). Thus, in situ elemental and Sr isotope variation in minerals from different paragenetic stages can be used to interpret formation process and source for both magmas and hydrothermal fluids.

Isotopic Evidence for Human Movement into Central England during the Early Neolithic

Isotope ratios of tooth enamel from ten Early Neolithic individuals buried in a long cairn at Whitwell in central England were measured to determine where they sourced their childhood diet. Five individuals have low Sr concentrations (11–66 ppm) and high 87Sr/86Sr ratios (0.7164–0.7212). Three individuals have relatively low 87Sr/86Sr ratios (0.712–0.711) and Sr concentrations ranging between 54 and 109 ppm. Two individuals have strontium isotope values that bridge the gap between the isotope compositions of these two groups. The high 87Sr/86Sr values are rare in human enamel and exclude sources within the biosphere of central England. Oxygen isotope values are comparable to those found within human archaeological populations buried in temperate regions of Europe. The strontium isotope results should be interpreted in the context of other evidence for migration from northern France to Britain during the Early Neolithic.

Biological diversity in an Islamic archaeological population: A radiogenic strontium isotope and craniometric analysis of affinity in Ottoman Romania.

Written accounts, as well as a previous craniometric study, indicate that migrations of non-Europeans and conversions of Europeans to Islam define Ottoman communities in Early Modern Europe. What is less clear are the roles of migration and admixture in generating intra-communal variation. This study combines craniometric with strontium isotope data to compare the cranial affinities of locally born and immigrant individuals. We predict that locally born individuals are more likely than non-locals to show evidence of admixture. Radiogenic strontium isotope data for 21 Ottomans were compared against archaeological faunal values. Sixteen individuals with intact crania were also measured and compared against two comparative source populations from Anatolia and Europe. Discriminant function analysis assigned unclassified Ottoans to either comparative group based on typicality probabilities, with potential admixture established via intermediate morphology between the two source populations. Strontium isotope values revealed relatively high proportions of non-locals, consistent with high mobility documented historically. The sexes differed, with more males classifying as "typically Anatolian" than females. Locals and non-locals also had different cranial affinity patterns, with most classifying either as "typically Anatolian" or "typically European." Contrary to expectation, none of the locals were identified as intermediate, suggesting admixture rates were relatively low. Consistent with historical records, the results revealed high levels of extra-regional migration, with most individuals identifiable as either typically Anatolian or European. Moreover, locals and non-locals differed craniometrically, with no signs of admixture between Anatolian migrants and European converts in locals. This suggests intra-communal divisions were maintained.

Status, kinship, and place of burial at Early Bronze Age Bab adh-Dhra': A biogeochemical comparison of charnel house human remains.

The Early Bronze Age (EBA; ca. 3,600-2000 BCE) of the southern Levant underwent considerable transformation as agro-pastoral communities began to utilize their land more intensively, constructing larger, fortified towns prior to site abandonment at the end of the third millennium. At the site of Bab adh-Dhra' in Jordan, the dead of the Early Bronze (EB) II-III (ca. 3,100-2,500 BCE) period were communally interred within charnel houses, but important disparities between these structures and their contents may be reflective of ownership and use by particular extended kin groups whose activity patterns, subsistence strategies, and even social status may have differed from one another. Subsequently, we hypothesized that differences in mobility and dietary intake may differentiate tomb groups from one another. Dental enamel from 31 individuals interred in three different Early Bronze Age charnel houses (A56, A22, A55) at Bab adh-Dhra', Jordan were analyzed for strontium, oxygen, and carbon isotope values. Strontium isotope ratios (range: 0.70793-0.70842) possessed medians that did not differ statistically from one another, but had ranges that exhibited significant differences in variance. Carbon isotope values ( = -13.2 ± 0.5‰, 1σ) were not significantly different. General similarities in human isotopic signatures between EB II-III charnel houses A22 and A55 suggest that their activities were likely similar to one another and agree with findings from excavated domestic spaces with little archaeological evidence for economic, social, or political differentiation. More variable strontium isotope ratios and lower carbon isotope values from A22 could reflect a greater involvement with pastoralist practices or regional trade, including the consumption of more 13 C-depleted foods, while those in A55 may have led a more sedentary lifestyle with greater involvement in cultivating orchard crops. All charnel houses contained nonlocal individuals likely originating from other Dead Sea Plain sites with no EB II-III cemeteries of their own, supporting the idea that extended kin groups throughout the region returned to Bab adh-Dhra' to bury their dead.

Mobility of nomads in Central Asia: Chronology and 87Sr/86Sr isotope evidence from the Pazyryk barrows of Northern Altai, Russia

In this study we report the first 87Sr/86Sr isotopic data and mobility analyses of the Pazyryk culture in Central Asia. Throughout prehistory the Altai Mountains represent a unique cultural frontier characterised by a perpetual state of transition, resulting from highly mobile nomadic inhabitants. We analysed human skeletal remains from barrows in the Manzherok region of the Altai Republic, Russian Federation. The analysis was based on 160 measurements of 87Sr/86Sr from Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Thermal Ionisation Mass Spectrometry (TIMS), in tandem with environmental samples and comparative animal material.The combined dating evidence and strontium isotopic values indicate that after the 5th century BC, residential mobility amongst Altaic nomads is rising, especially long-distance female mobility, leading to contact acquisition with extrinsic territories of Central Asia. The 87Sr/86Sr isotopic evidence from Manzherok suggests that members of the Altaic population might have been buried in Scythian tombs located in Tuva and Khakassia, most notably in the Arzhan barrows.

Understanding Middle Neolithic food and farming in and around the Stonehenge World Heritage Site: An integrated approach

Little synthesis of evidence for Middle Neolithic food and farming in Wiltshire, particularly in and around the Stonehenge World Heritage Site (WHS) has been possible, until now, due to a paucity of assemblages. The excavation of a cluster of five Middle Neolithic pits and an inhumation burial at West Amesbury Farm (WAF) has prompted a review of our understanding of pit sites of this period from the county. Bioarchaeological assemblages are used to investigate evidence for the consumption of animal and plant-based foods, and for agricultural and pastoral farming. For the first time Middle Neolithic zooarchaeological evidence, including strontium isotope data, is considered alongside archaeobotanical data, and radiocarbon dating.The absence of cultivated plants from WAF and contemporary sites in the county is consistent with the hypothesis that the reduction in cereal cultivation and greater reliance of wild plants witnessed in the later part of the Neolithic in southern England began in the Middle Neolithic. The zooarchaeological evidence from the same sites demonstrates that the shift away from cereal cultivation may be concurrent with, rather than earlier than, an increase in the relative proportion of deposited pig bones relative to cattle.Both cattle and pigs deposited in pits at WAF have strontium and sulphur isotope values consistent with the local biosphere, and therefore were potentially raised in the area. Zooarchaeological data from WAF compliments that from human dental calculus and lipid residues in associated Peterborough Ware pottery that local cattle husbandry included exploitation of dairy. It also highlights the presence of consistent food preparation methods between pits as seen through butchery practice.The faunal and archaeobotanical remains from contemporary pit deposits suggest that similar farming and subsistence strategies can be proposed across the county, though with some inter-site variation in deposition. Together these excavated pit sites are likely to represent only a sample of those present in the area. Application of a similar integrated approach to material from other Middle Neolithic pits holds potential for better understanding of food and farming in this previously neglected period.

Reconstructing the origins of the Perrins Ledge cremains using strontium isotope analysis

Strontium isotope (87Sr/86Sr) analyses have been used effectively to reconstruct the origin of osteological remains that have not been exposed to increasing temperatures. However, previous research has shown that no thermally induced changes occur to original strontium isotope values (87Sr/86Sr) of bone and tooth specimens that have been subjected to temperatures between 100 and 1000 degrees Celsius, though the published literature regarding strontium isotope ratio stability and survivorship in thermally altered bone and teeth is limited. This is surprising given the potential implications for geolocation inquiries of cremains. This research demonstrates the utility and potential of strontium isotope analysis (87Sr/86Sr) in the contexts of thermally altered osteoarchaeological materials with the focus to reconstruct the geographic origins of the prehistoric cremated human remains from the Late Woodland period (600–850 CE) Perrins Ledge crematory, located in the Lower Illinois River Valley of the American Midwest. This mortuary site is unique in both regional and temporal contexts as an isolated crematorium structure containing at least 13 individuals (ten adults and three non-adults) represented by burned human skeletal remains of unknown origins. Strontium isotope signatures derived from bone and enamel samples of the cremains are compared with values obtained from osteoarchaeological faunal remains from three contemporary neighboring sites (Carlin, Apple Creek, and Newbridge) using thermal ionization mass spectrometry. Results indicate that the majority of the Perrins Ledge individuals reflect signatures beyond the standard (two-sigma) range considered local, with one adult bone and enamel sample and two of the three non-adult enamel samples that mirror local signatures.

Restricted pasturing of domesticated cattle at a Late Neolithic settlement in Central Germany

Domestic cattle (Bos taurus) were one of the most important animal resources exploited by farming communities throughout the Neolithic period in Central Europe. However, little is currently known about cattle husbandry practices in use for Late Neolithic communities located in Central Germany. Here, we present new zooarchaeological and isotopic data in order to better understand cattle management strategies used during the late fourth and early third millennia BCE at the Late Neolithic Bernburg settlement of Hundisburg-Olbetal in Central Germany. Strontium isotope values of cattle tooth enamel reveal that these animals were most likely herded on local pastures. The overall range of carbon isotope values of sequentially sampled cattle teeth suggests the ingestion of graze that grew in open C3-environments all year round. Furthermore, the observed temporal offset between maximum carbon and oxygen isotope values most likely reflect a herding strategy where cattle grazed on open pastures in the floodplains during the growing season and were possibly kept near the settlement on stubble fields after harvest. Altogether, these data indicate Late Neolithic cattle management systems at the Bernburg settlement of Hundibsurg-Olbetal were small in scale and likely focused on meat production for household subsistence.

Isotopic evidence for changing human mobility patterns after the disintegration of the Western Roman Empire at the Upper Rhine

The dissolution of the Western Roman Empire and the rise of Early Medieval kingdoms during the fifth and sixth century AD were accompanied by profound social, economic, and cultural changes. While several studies focus on the investigation of the reasons explaining the underlying cause of this transition based on written and archeological evidence, it is still unclear in how far this major political turnover affected communities on a regional and local level. Here, we conduct strontium, oxygen, and carbon isotope analyses of human tooth enamel from 95 individuals from two Early Medieval cemeteries located in the northern Upper Rhine region in order to investigate population dynamics during a period of political upheaval. The strontium isotopic analysis has revealed that a high number of individuals born outside the Upper Rhine region, but relative few individuals indigenous to the area, were interred in cemeteries newly founded at the end of the fifth century AD. During the sixth century AD, the cemeteries are dominated by individuals local to the Upper Rhine region. However, the presence of individuals with strontium isotope values below the biologically available strontium isotopic range indicates the arrival of newcomers from different regions compared to earlier periods which may reflect a change of contacts and relationships in the course of the sixth century AD. Overall, the results of this study suggest that the change of human mobility patterns in this region is a reaction to the socio-political dynamics of the transformation period between Late Antiquity and the Early Middle Ages.

Re-interpreting ancient Maya mobility: a strontium isotope baseline for Western Honduras

Isotopic data are regularly employed to investigate and reconstruct migration, diet, and other anthropological questions about the past. Here we present new radiogenic strontium isotope values for western Honduras that have been understudied in relation to mobility among the ancient Maya in Mesoamerica. We employ biologically available isotopic compositions (87Sr/86Sr) derived from local fauna and plants to create a baseline for these regions to determine the degree of movement into populations at Late Classic (600–820 CE) Copan, Honduras. Our results demonstrate that while movement certainly occurred within the Maya region, it also may have included areas beyond the perceived physical and cultural boundaries of the Maya world. We focus on the biogeochemical data to highlight how paleomobility (87Sr/86Sr) data should be used cautiously to understand mobility across Mesoamerica, and to consider how non-Maya peoples were likely part of Maya communities.

Strontium isotope evidence for human mobility in the Neolithic of northern Greece

Strontium isotope ratios are widely used in archaeology to differentiate between local and non-local populations. Herein, strontium isotope ratios of 36 human tooth enamels from seven archaeological sites spanning the Early to Late Neolithic of northern Greece (7th–5th millennia B.C.E.) were analysed with the aim of providing new information relating to the movement of humans across the region. Local bioavailable 87Sr/86Sr signals were established using tooth enamel from 26 domestic animals from the same Neolithic sites. 87Sr/86Sr values of faunal enamel correlate well with predicted strontium isotope ratios of the local geology. This is consistent with animal management occurring at a local level, although at Late Neolithic sites strontium isotope values became more varied, potentially indicating changing herding practices. The strontium isotope analysis of human tooth enamel likewise suggests limited population movement within the Neolithic of northern Greece. Almost all individuals sampled exhibited 87Sr/86Sr values consistent with having spent their early life (during the period of tooth mineralisation) in the local area, although movement could have occurred between isotopically homogeneous areas. The strontium isotope ratios of only three individuals lay outside of the local bioavailable 87Sr/86Sr range and these individuals are interpreted as having spent their early lives in a region with a more radiogenic biologically available 87Sr/86Sr. Mobility patterns determined using Sr isotope analysis supports the current evidence for movement and exchange observed through studies of pottery circulation. Suggesting limited movement in the Early and Middle Neolithic and greater movement in the Late Neolithic.

Diet and mobility of fauna from Late Neolithic–Chalcolithic site of Perdigões, Portugal

Perdigões is located in the Alentejo region of south-eastern Portugal, with occupational phases dating from the Late Middle Neolithic to Late Chalcolithic/Early Bronze Age (middle 4th and 3rd millennium BCE) periods. It is a complex site that can be considered as a centre of social aggregation and a part of a larger settlement network. In this study, the nature of animal subsistence patterns as well as husbandry management practices and mobility are examined using stable carbon and nitrogen isotopic values from bone collagen of 35 archaeological faunal samples (Canis familiaris, Bos taurus, Bos primigenius, Sus sp., Ovis/Capra, Cervus elaphus, O. cuniculus, Equus sp.) and strontium isotope (87Sr/86Sr) analysis of 23 enamel samples. To provide necessary biological 87Sr/86Sr baseline data, the strontium isotopic composition of 14 modern plant samples were measured. The stable carbon and nitrogen isotope data shows that animals subsisted on a selection of C3 terrestrial resources, with subtle differences in animal husbandry practices in domesticated animals, while strontium isotope analysis shows that <5% of analysed fauna is consistent with the local bioavailable strontium isotopic range. Other animals can be divided into two clusters – those having strontium isotope values either lower or higher than the bioavailable range, showing that most of the fauna browsed and grazed within 10 km of the site's surrounding landscape, which is not such an unusual practice during prehistoric times.

Trace elements and isotope data of the Um Garayat gold deposit, Wadi Allaqi district, Egypt

Trace element composition of sulfides and O, C, Sr and S isotopic data are assessed to constrain the evolution and potential fluid and metal sources of the Um Garayat gold deposit. Ore microscopy and BSE investigations of quartz veins show blocky arsenopyrite and pyrite replaced in part by pyrrhotite, chalcopyrite, sphalerite, galena, and gersdorffite. Free-milling gold occurs commonly in close association with the late sulfides, and along fractures in pyrite. On the other hand, recrystallized pyrite is disseminated in host metavolcaniclastic/metasedimentary rocks that commonly contain carbonaceous material. In situ LA-ICP-MS analysis of sulfides shows the recrystallized pyrite enriched in most trace elements, while blocky pyrite contains only some traces of arsenic. Detected concentrations of gold (up to 17 ppm) were only reported in arsenopyrite disseminated in quartz veins. The δ34S values of blocky pyrite and pyrrhotite in quartz veins define a narrow range (1.6 to 3.7‰), suggesting a homogenous sulfur source which is consistent with the dominantly mafic host rocks. The recrystallized pyrite has a distinctive sulfur isotope composition (δ34S − 9.3 to − 10.6‰), which is rather comparable to diagenetic sulfides. Hydrothermal carbonate in quartz veins and wallrock have nearly constant values of δ18O (10.5 to 11.9‰) and δ13C (− 4.2 to − 5.5‰). Based on constraints from mineral assemblages and chlorite thermometry, data of six samples indicate that carbonate precipitation occurred at ~ 280 °C from a homogenous hydrothermal fluid with δ18OH2O 4.4 ± 0.7‰ and δ13C = 3.7 ± 0.8‰. Strontium isotope values of two samples (87Sr/86Sr = 0.7024 and 0.7025) are similar to the initial 87Sr/86Sr ratios of island arc metabasalts (~ 710 Ma) in the South Eastern Desert. The generally homogenous sulfur, C, O, Sr isotope data are suggestive of metamorphogenic fluids, likely produced from dominantly mafic volcanic rocks at the greenschist–amphibolite facies transition.

Weathering processes, catchment geology and river management impacts on radiogenic (87Sr/86Sr) and stable (δ88/86Sr) strontium isotope compositions of Canadian boreal rivers

Radiogenic (87Sr/86Sr) and stable (δ88/86Sr) strontium isotope compositions spanning a calendar year are reported for rivers from across subarctic Canada that drain contrasting lithologies ranging from Precambrian bedrock (Koksoak, Great Whale and La Grande rivers of Northern Quebec) to carbonate and clastic Phanerozoic sedimentary rocks of the Western Interior Platform (Nelson River, of central and western Canada). The 87Sr/86Sr isotopic compositions of the river waters reflect the underlying geology, with rivers draining the Precambrian Shield having higher 87Sr/86Sr ratios (0.727–0.734) than the Phanerozoic dominated Nelson River (0.713). The stable strontium isotope values (δ88/86Sr) range from 0.26 to 0.39‰, with the values for the Nelson River overlapping those of the other three. Rivers that have not been developed for hydroelectric power show a seasonal variation in the 87Sr/86Sr ratios, whereas those that have been diverted or dammed show little or no seasonal variation due to increased residence time of their water in hydroelectric reservoirs. The three rivers from Northern Quebec show discrete ranges in their 87Sr/86Sr and δ88/86Sr isotope compositions that correlate with the Ca/Sr and Na/Sr ratios of the river water. These correlations are interpreted to reflect differential chemical weathering of felsic versus mafic source rocks and/or of surficial sediment vs bedrock sources.