Dissertations / Theses on the topic 'Strontium isotopes'
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Jones, Charles Edward. "Strontium isotopes in Jurassic and Early Cretaceous seawater." Thesis, University of Oxford, 1992. http://ora.ox.ac.uk/objects/uuid:fe3733bd-8e31-4bba-a78b-6d8275a0075f.
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The collection and analysis of a large number of belemnites and oysters with excellent biostratigraphic and diagenetic control has resulted in a highly detailed determination of the seawater Sr-isotope curve through the Jurassic and Early Cretaceous. The new data confirm the broad trends established by previous work, but the much sharper resolution of the new data allows the application of Sr-isotope stratigraphy with an optimal stratigraphic resolution of ± 1 to 4 ammonite subzones (± 0.5 to 2 Ma). The data show a general decline from the Hettangian (Early Jurassic) to a minimum in the Callovian and Oxfordian (Middle/Late Jurassic). This is followed by an increase through the Kimmeridgian (Late Jurassic) to a plateau reached in the Barremian (Early Cretaceous). In addition, there are major negative excursions in the Pliensbachian/Toarcian (Early Jurassic) and Aptian/Albian (Early Cretaceous). Stable isotope data collected from belemnites and oysters have resulted in the most extensive Jurassic δ13C and δ18O database to date. While both the carbon and oxygen data appear to give reasonable marine signals, the scatter in the data suggests that future research must document possible biological fractionation effects and develop better indicators for the diagenetic alteration of 613C and 6i 8O. The final chapter documents an unexpected correlation between sudden shifts in the Sr-isotope curve, the occurrence of positive 513C excursions, and the eruption of flood basalts. In the Jurassic and Cretaceous there is a correlation in time between sudden downward shifts in the Sr-isotope curve (Pliensbachian, Aptian, Cenomanian/Turonian), the occurance of positive 613C excursions, and the eruption of flood basalts. Each of these major downward shifts in the Sr-isotope curve is followed by a sudden upward shift, which although associated with a positive 613C excursion is not associated with an episode of flood basalt volcanism. In the Cenozoic the Sr-isotope curve no longer displays downward shifts, but the correlation continues between the occurrence of flood basalts and positive 513C excursions. Several lines of evidence suggest that the eruption of flood basalts is associated with pulses of hydrothermal activity, and that this hydrothermal activity brings about the conditions necessary for the genesis of carbon-burial events.
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Cruz, Steffen James. "Single particle structure of exotic strontium isotopes." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61928.
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The sudden onset of ground state deformation and the emergence of shape-coexisting states in the vicinity of N~60 and Z~40 has been a subject of substantial interest for many years. It has been shown that the emergence of deformed low-energy configurations can be explained in the shell model by the evolution of single particle structure and the interaction between protons and neutrons in certain valence orbitals. However, the numerous theoretical models that have been developed for this transitional region are limited by the experimental data that is available. In particular, a description of the underlying single particle configurations of low energy states is essential for a detailed description of this region.
In this work, the single particle structure of states in ⁹⁵Sr and ⁹⁶Sr has been investigated through the one-neutron transfer reactions ⁹⁵ ⁹⁶Sr(d,p) in inverse kinematics at TRIUMF. In each of these experiments, a 5.5 MeV/u Sr beam was impinged on a 5.0 mg/cm² CD₂ target, and emitted particles and γ-rays were detected using the SHARC and TIGRESS detector arrays, respectively. Using an angular distribution analysis, firm spin assignments have been made for the first time of the low-lying 352 keV, 556 keV and 681 keV excited states in ⁹⁵Sr from ⁹⁴Sr(d,p), and a constraint has been made on the spin of the higher-lying 1666 keV excited state in ⁹⁵Sr. Similarly, angular distributions have been extracted for 14 states in 96Sr from ⁹⁵Sr(d,p), and new experimental constraints have been assigned to the spins and parities of 8 states in ⁹⁶Sr. Additionally, two new states in ⁹⁶Sr have been identified in this work. A measurement of the mixing strength between the 1229 keV and 1465 keV shape-coexisting states in ⁹⁶Sr was also made, which was found to be a²=0.48(17).Science, Faculty of
Physics and Astronomy, Department of
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Fawcett, M. J. "High sensitivity collinear spectroscopy on strontium isotopes." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233278.
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Wallace, Jenelle. "Reconstructing Equid Mobility in Miocene Florida Using Strontium Isotopes." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1530269000198412.
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Yobregat, Elsa. "Les isotopes du strontium et du baryum dans le Système Solaire précoce." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEN002/document.
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Des anomalies nucléosynthétiques ont été observées dans des météorites pour plusieurs éléments. L’ampleur de ces anomalies ainsi que leur répartition entre les objets du système solaire renseigne sur le degré d’hétérogénéité de la nébuleuse solaire. L’étude des phases porteuses de ces anomalies procure des informations sur les processus à l’origine de cette hétérogénéité. Les datations par radiochronomètres de courte période reposent sur la répartition hétérogène des éléments père et fils. L’utilisation de ces outils nécessite donc l’étude parallèle des variations nucléosynthétiques de ces élémentsNucleosynthetic anomalies have been observed in meteorites for many elements. The magnitude and repartition of these anomalies provide information about the degree of heterogeneity of the solar nebula. The study of the nucleosynthetic anomalies carriers could also give insight into the processes responsible for this heterogeneity. The presence or absence of small variations in nucleosynthetic processes is a key for the use of the short-lived radiochronometers. Small variations in the repartition of the parent or daughter isotope can lead to misinterpretations of relative ages
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Ramsay, Eric Barnaby. "Ground state properties of strontium nuclides by laser spectroscopy." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75755.
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Isotope shifts of twenty-two isotopes of strontium, $ sp{78}$Sr to $ sp{100}$Sr excluding $ sp{99}$Sr, and three isomers of strontium, $ sp{83 rm m,85m,87m}$Sr, have been measured using laser spectroscopy. The nuclear spins, magnetic and quadrupole moments, have been extracted from the data for all odd isotopes. The changes in mean square charge radii have also been evaluated for all isotopes and isomers.The changes in mean square charge radii, which are compared to the predictions of the droplet model and Hartree-Fock plus B.C.S. calculations, show a pronounced shell effect at the closed neutron shell at N = 50 and a sharp increase at N = 60. The theoretical analysis suggests that the change in mean square charge radii for N = 60, 62 is due to the onset of a large static deformation. For the remaining isotopes, the changes are attributed to a change in size, a change in the predominantly dynamic deformation, and a change in the diffuseness of the nuclear charge distribution.
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Dennebouy, Stéphane. "Mise en évidence et caractérisation de la variabilité haute fréquence du rapport 87 Sr / 86 Sr du strontium océanique." Paris, ENMP, 2001. http://www.theses.fr/2001ENMP1102.
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Drouet, Thomas. "Etude de l'origine du calcium dans les écosystèmes forestiers par les méthodes de géochimie et de dendrochime isotopiques du strontium." Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210940.
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El, Meknassi Sofia. "Enregistrement des isotopes du Sr dans les coquilles et l'eau de mer côtière : réévaluation multi-échelles du cycle du Sr pour des implications paléoenvironnementales et chimiostratigraphiques." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30200.
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Les reconstitutions passées de la composition isotopique en Sr (87Sr/86Sr) des squelettes carbonatés d'organismes marins (MCS) sont très largement utilisées par les chimiostratigraphes et les paléoenvironnementalistes car elles permettent de reconstituer les variations du rapport 87Sr/86Sr de l'océan au cours des temps géologiques. Les reconstitutions paléoenvironnementales et les datations chimiostratigraphiques reposent sur le consensus que les MCS précipitent leurs tests carbonatés à l'équilibre isotopique avec l'eau de mer qui est homogène à l'échelle globale en raison d'un temps de résidence du Sr (2 Ma) supérieur au temps de brassage océanique (1600 ans). Leur fiabilité en tant qu'outils chimiostratigraphiques peut être remise en question, notamment parce qu'aucune évaluation formelle des biais biologiques et environnementaux n'a été réalisée à l'échelle mondiale. Cette étude propose donc une réévaluation à l'échelle globale de la signature isotopique en Sr des MCS et de l'eau de mer d'environnements côtiers. La signature isotopique des MCS et de l'eau côtière est largement influencée par des apports continentaux qui peuvent modifier les signatures isotopiques de ces derniers. De fait, au vu de ces hétérogénéités cette étude a recalculé le temps de résidence du Sr à plusieurs échelles spatiales. Elle propose de façon générale une meilleure compréhension des processus côtiers sur la signature isotopiques de l'eau et des MCSPast reconstructions of the isotopic Sr composition (87Sr / 86Sr) of marine carbonate skeletons (MCS) are very widely used by chemostratigraphs and palaeoenvironmentalists because they allow to reconstruct variations of the 87Sr/86Sr ratio of the ocean across geological time. Paleoenvironmental reconstructions and chemostratigraphic dating are based on the consensus that MCS precipitate their carbonate skeletons at the isotopic equilibrium with surrounded seawater, that is considered as homogeneous at global scale due to a residence time of Sr (2 Ma) higher than the global ocean mixing duration(1600 years). Their reliability as chemostratigraphic tools can therefore be questioned, in particular because no formal evaluation of biological and environmental biases has been carried out at a global scale. This study proposes a global reassessment of the Sr isotopic composition of both MCS and seawater of coastal and oligotrophic environments. The isotopic signature of MCS and coastal water is largely influenced by continental inputs that can modify their isotopic signatures. In fact, given these heterogeneities, this study has recalculated the Sr residence time. Finally, this study propose a better understanding of the global strontium cycle at different time scale
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Vaiglova, Petra. "Neolithic agricultural management in the Eastern Mediterranean : new insight from a multi-isotope approach." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:c8824136-da35-43b2-a700-f458d0cc2fdf.
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The work presented in this dissertation explores the nature of agro-pastoral strategies developed by Neolithic farmers as a way to understand how early food production was inter-twined with environmental and socio-economic opportunities and constraints. Towards this end, a multi-isotope approach is used to address questions of scale and intensity of crop cultivation and animal management at the archaeological sites of Kouphovouno, southern Greece, Makriyalos, northern Greece, and Çatalhöyük, south-central Turkey. Measurements of stable carbon, nitrogen, oxygen and strontium isotope values of carbonized plant remains, human and animal bone collagen and animal tooth enamel are used to examine the similarities and differences in the types of treatments that individual species of plants and animals received during the agricultural cycle at the distinct locations. The results show that farmers at the three sites developed variable methods for exploiting the arable and pastoral landscape and catering to their economic and culinary needs. The discussion considers the implications of these findings to our understanding of the complexity and adaptability of early farming systems.
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John, Eleanor Heulwen. "Strontium and sulphur isotopes and the origin of Mid-Late Palaeozoic mass extinctions." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493302.
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This project focuses on two Palaeozoic mass extinction events: the Frasnian-Famennian crisis of the Late Devonian and the end-Guadalupian event of the Permian for which similar extinction mechanisms have been proposed. These have been evaluated by examining the nature of the Sr and S isotopic systems during these intervals. Proposed extinction mechanisms for the Late Devonian event include extraterrestrial impacts, rapid sea-level fluctuations, climate change eutrophication and the spread of anoxia in bottom waters. Many models invoke changes in nutrient fluxes related to proposed increases in continental weathering or hydrothermal/volcanic fluxes but these theories have not been tested on a global scale. This study attempted to address this by compiling high resolution 87Sr/86Sr ratio curves for an interval spanning the FrasnianFamennian boundary based on measurements in well-preserved conodont apatite from sections in Poland and Iowa.
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Row, Kristen. "Strontium isotopes and geolocation: the pathway for identification of victims in Medellín, Colombia." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12206.
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Thesis (M.S.)--Boston UniversityThe goal of this study is to determine if strontium isotope analysis (87Sr/86Sr) is useful when applied to modern dental enamel samples, specifically from Medellín, Colombia. Strontium isotope analysis has been used extensively in the archaeological literature with only a few studies in the forensic literature. There is a need for identification of individuals whose remains are found in Colombia, due to the conflict that has taken thousands of lives. Samples from 75 teeth of 61 individuals were taken to determine the 87Sr/86Sr isotope ratio. The samples were processed using a thermal ionization mass spectrometer (TIMS) at Boston University in the Earth Science Department. The overall mean (87Sr/86Sr) = 0.70739 +/- 0.00159. The results are inconclusive, it was found that there is no significant difference between isotope ratios in different regions of Colombia. This indicates that more samples from other geographic locations in Colombia are needed to accurately sort populations in Colombia. Modernization, specifically imported food has an effect on strontium isotope ratios in dental enamel of individuals; this method needs to be tested with other modern populations in order to conclusively state that it does not work with modern populations.
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Hale, Colin Andrus. "Strontium Isotopes-A Tracer for Dust and Flow Processes in an Alpine Catchment." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7459.
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Stream chemistry changes in response to snowmelt, but does not typically reflect thechemistry of the snowpack. This suggests that flow processes between snowmelt and streamsystem, such as interactions with the soil and bedrock, have an important control on waterchemistry and highlight the complex flow pathways from the snowpack to stream. To investigateflow processes in the upper Provo River watershed, northern Utah, we sampled three sites on theriver ~20 times per year during 2016 and 2017. The sites, from highest elevations to lowest wereSoapstone, Woodland, and Hailstone, corresponding to locations of active stream gauges. Toidentify possible water sources to the stream during snowmelt, water samples were taken forsnow, ephemeral streams, soil water, lake, and spring water. To investigate potential impacts ofmineralogy, samples were taken for dust, soil and bedrock. The upper Provo River showeddistinct temporal variation in filtered (<0.45 microns) stream water for 87Sr/86Sr, dissolvedorganic carbon (DOC), silica (Si), and Lead (Pb) during the snowmelt season. The watershed hasdistinct 87Sr/86Sr ratios for bedrock (0.7449)
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Stevenson, Emily Isabel. "Stable strontium isotope fractionation in marine and terrestrial environments." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:a2d97fc7-3e9d-484a-8026-11c118fcc3fd.
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The work reported in this thesis applies a new isotope tracer, stable strontium isotopes (δ88/86Sr), to address questions concerning changes in global climate that occur in response to continental weathering processes, and to constrain the modern marine geochemical Sr cycle. Stable Sr isotopes are a relatively new geochemical proxy, and as such their behavior needs to be understood in differing forms of marine calcium carbonate, the archives from which records of past stable Sr variability in the oceans can be constructed. Foraminifera, coccoliths and corals (both aragonite and high Mg calcite) acquire δ88/86Sr values lighter than that of modern day seawater, (approximately 0.11, 0.05, 0.2 and 0.19 ‰ lighter than seawater at ~25°C respectively) providing a measureable offset which can be used to constrain the modern Sr outputs from the ocean and provide a better understanding of the modern Sr cycle. Using foraminifera as a sedimentary archive the first marine δ88/86Sr record of seawater over the last two glacial cycles has been constructed, and used to investigate changing carbonate input and output over this 145 kyr period. Modelling of the large excursion of δ88/86Sr to heavier values during Marine Isotope Stage (MIS) 3, reveals that this is more likely to be due to local changes in seawater or post-depositional alteration, rather then whole ocean changes. In the terrestrial environment δδ88/86Sr has been measured in the dissolved load of rivers from the Himalaya. It is found that, in general, rivers draining carbonate catchments possess lighter isotopic δ88/86Sr values than those from rivers draining silicates. Covariations of either δ88/86Sr vs. δ30Si or δ88/86Sr vs. 1/[Sr] can be used to distinguish between rivers draining different catchment areas.
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Gentry, David Keith. "Seasonal isotope and trace-metal profiles of serially-sampled Conus gastropods: proxies for paleoenvironmental change." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/3871.
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We test the fidelity of shallow-water gastropod skeletons as multi-proxy archives of seasonal paleo-environmental change by performing isotopic and trace-metal analyses on specimens of Conus ermineus from the Gulf of Mexico. Four adult specimens were collected from Stetson Bank in the Flower Garden Banks National Marine Sanctuary during the summer of 2002. Shell samples were milled along axes of growth to produce time-series profiles spanning up to eight years. We corrected the profiles for growth rate effects and compared the tuned results with in situ temperature and salinity records at the reef surface and temperature profiles from nearby surface buoys. Examination of sample densities in δ18O cycles shows that shell growth is faster during summers and slower during winters. Tuning the profiles versus time yields δ18O values that co-vary closely with seasonal temperatures to a high degree of coherency (R2 = 0.84). The δ13C profiles show cyclic variation modified by ontogenetic decreases in δ13C. These ontogenetic trends are attributable to decreasing metabolic efficiency, while seasonal cycles reflect hydrographic changes in the gastropods habitat. Salinity and δ13C of dissolved inorganic carbon show a strong correlation at Stetson Bank (R2 = 0.80), and early summer shell δ13C minima coincide with local salinity minima during times of peak river discharge. The terminations of these δ13C minima occur during annual upcoast reversals of shelf currents in this area. These effects are augmented by summer stratification and productivity minima that further decrease seawater δ13C. Sr/Ca ratios increase through ontogeny, most likely due to decreasing metabolic efficiency. However, seasonal variations in Sr/Ca profiles show strong similarity with δ18O profiles, confirming the temperature dependence of Sr/Ca and minimal influence of salinity on shell δ18O at Stetson Bank. The results of this study show that tuned δ18O and Sr/Ca profiles can be used to reconstruct seasonal paleotemperatures. Carbon isotope profiles and environmental data also demonstrate the utility of Conus δ13C as a proxy for freshwater flux and shelf circulation.
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Salgado, Souto Sergio Adrian, and Souto Sergio Adrian Salgado. "A Re-Os Geochronology and Multi Stable Isotope (C, N, S, Sr, Pb) Systematics of Source Rocks and Crude Oils from the Sonda de Campeche Petroleum System, Mexico." Diss., The University of Arizona, 2018. http://hdl.handle.net/10150/626760.
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In this work, I present a multi-isotopic study (carbon, nitrogen, sulfur, strontium and lead) and Re-Os geochronology in rocks and crude oils of the Sonda de Campeche Petroleum System (SCPS). Since crude oils are complicated chemical systems easily disturbed, the Re-Os isotopic system could be affected if secondary processes perturb crude oils. Therefore, the multi stable isotopic study allows the identification of the presence and grade of these secondary processes in crude oils.
The δ13C values of crude oils from the SCPS distinguish between: 1) crude oils with the fingerprint of source rocks of hydrocarbons (-28.3 to -26.7 ‰), and 2) crude oils with the fingerprint of the reservoir rocks (-25.5 to -24.9 ‰). Similarly, the δ15N values reveal that crude oils, during migration or trapping processes mimic the isotopic composition of the reservoir rocks of the Ek-Balam Formation. Furthermore, the δ34S values of crude oils from the SCPS (-8.0 to -2.5 ‰) show an absence of a thermal sulfate reduction (TSR) signature, which likely means that the use of Re-Os systematics in crude oils and rocks in the SCPS is appropriate.
Strontium and lead measurements show crude oils have an isotopic composition different from rocks from the Edzna Formation but similar to rocks of the Akimpech and Ek-Balam formations, indicating that crude oils received Sr and Pb from the trapping rocks during migration or trapping processes, producing a isotopic mixing trend with rocks of these formations. Specifically, the lead isotope composition allows the identification of a source of lead never recorded before, the Guichicovi Complex. The isotopic data suggest that this Grenville Complex has been feeding with detrital material to the sedimentary rocks from Bacab, Ek-Balam and Akimpech formations in the SCPS, and in consequence contributing to the final isotopic composition of crude oils as well.
Re-Os geochronology of rocks from the Edzna and Akimpech formations (152 ± 4 Ma; and 158.6 ± 5.5 Ma, respectively) provides precise ages of deposition that coincide with the ages proposed in previous studies based on the fossil record. Re-Os geochronology in crude oils yield ages with low uncertainty and moderate MSWD values, reflecting a rapid formation and migration process that occurred during evolution of the SCPS. The age of crude oils (28.3 ± 5.5 Ma) broadly agrees with petroleum generation models proposed by PEMEX.
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Zattoni, Ana Paula. "Separation and analysis of Sr-90 and Zr-90 for nuclear forensic applications." Master's thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26052.
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Le présent travail porte sur le développement technologique pour déterminer l'âge des sources de radiostrontium à travers du rapport [Zr-90]/[Sr-90], en utilisant les techniques de spectrométrie de masse et scintillation liquide pour quantifier les deux isotopes. Parce que Sr-90 et Zr-90 sont des interférences isobariques en spectrométrie de masse, une séparation radiochimique est nécessaire pour isoler du Zr-90 avant son analyse. Parmi quatre résines commerciales, la résine DGA a fourni la meilleure performance pour isoler le Zr-90 du Sr-90. Des récupérations supérieures à 99% pour le Zr-90 ont été obtenues. La résine DGA était aussi l'approche la plus rapide et la plus efficace pour éliminer les interférences isobariques du Sr-90 et aussi de l’Y-90 potentiellement présents dans des échantillons contenant des niveaux élevés de radioactivité. Des expériences impliquant l’utilisation d’une cellule de collision pour éliminer des interférences isobariques ont fourni des facteurs de décontamination insuffisants pour des applications en criminalistique nucléaire.In this work, a technological development to determine the age of radioactive strontium sources through the [Zr-90]/[Sr-90] ratio using mass spectrometry and liquid scintillation to quantify both isotopes is presented. Because Sr-90 and Zr-90 are isobaric interferences in mass spectrometry, a radiochemical separation to isolate Zr-90 has been shown to be mandatory prior to analysis. Four commercial resins (AG50W-X9, Dowex1-X8, Sr and DGA resins) were tested to isolate Zr-90 from Sr-90. Best performance was observed for the DGA resin, including recoveries higher than 99% for Zr-90. DGA has also demonstrated to be the faster approach and the most efficient not only to eliminate isobaric interferences from Sr-90, but also from Y-90, potentially present in samples containing high levels of radioactivity. Experiments using a collision cell to eliminate isobaric interferences in a triple quadrupole mass spectrometer (ICP-QQQMS) have also been carried out, but results have demonstrated insufficient decontamination factors for nuclear forensic applications.
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Brinck, Elizabeth L. "Assessing potential environmental impacts from coal bed natural gas produced water using strontium isotopes." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445039651&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Brazier, Jean-Michel. "Rôle des phases minérales des sols en tant que réservoirs de nutriments : approche expérimentale (abiotique), en milieu naturel et multi-isotopique (isotopes stables Ca-Sr)." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAH005/document.
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Ce travail de thèse a appréhendé les mécanismes de stockage/libération, d’un point de vue élémentaire et isotopique, du calcium (Ca) et du strontium (Sr) sur ou dans des phases minérales communes des sols (minéraux primaires, minéraux argileux, oxy-hydroxydes, carbonate pédogénétiques). Une méthode de mesure robuste du δ88Sr a dû être développée et validée par la mesure de matériaux de références internationaux, pour la plupart jamais mesuré dans la littérature. Les résultats montrent que l’adsorption du Ca sur des minéraux phyllosilicatés génère un fractionnement isotopique par prélèvement préférentiel de l’isotope léger (40Ca) dans nos conditions expérimentales lorsque les minéraux possèdent une charge structurale et une surface spécifique importante et/ou un espace interfoliaire ouvert à l’adsorption de cations hydratés. Une étude sur des rhizolithes en milieu naturel a mis en avant que l’utilisation des isotopes du Ca et du Sr permet un traçage de source et de mécanismes efficaces dans les thématiques touchant au stockage de ces deux éléments dans les solsThis PhD thesis examined the mechanisms of storage and release, from and elementary and isotopically point of view, of calcium (Ca) and strontium (Sr) onto or into mineral phases commonly encountered within soils (primary minerals, clay minerals, oxy-hydroxides, pedogenic carbonate). A robust δ88Sr measurements method had to be developed in the laboratory and validated by the measurement of international reference materials, mostly never measured in the literature. The results of this work show that Ca adsorption onto phyllosilicate minerals generates a quantifiable isotopic fractionation by preferential uptake of the light isotope (40Ca) under our experimental conditions when the minerals have a significant structural charge and specific surface area and/or an interlayer space open to hydrated cations adsorption. A study on rhizoliths in natural environment has also highlighted that the combination of Ca and Sr isotopes allows an effective tracing of sources and mechanisms in the problematic related to the storage of these two elements within soils
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Bouchard, Laurianne. "Rb-Sr Age Estimates of Pore Fluids in Sedimentary Rocks, DGR Site, Kincardine, Ontario." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32271.
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This study is part of a project aiming for the long-term burying of nuclear wastes in Kincardine, Ontario. Bedrock formations as well as their associated waters were analyzed in drill cores from the Michigan sedimentary basin, southwest Ontario.
This research utilizes geochemistry combined to strontium and rubidium isotope ratios in order to determine the origin of porewaters from Ordovician shales and limestones. It is demonstrated that these waters are the result of a mixing line between the Silurian (Guelph) and Cambrian groundwaters. This last end-member was also mixed with Precambrian brines to some extent.
Strontium and rubidium isotopes also demonstrated rubidium in clays were leached by porewaters over time. Once in solution, radioactive rubidium decayed into strontium over time. This process explains the accumulation of radiogenic strontium observed in porewaters.
An age estimate for the deposition of carbonates and other evaporates was calculated with the Rb-Sr isotope system. The calculated age is 453.7 million years before present for dolomites, which is consistent with the history of the site. It was possible to gen an approximate age of 339.7 million years for the formation of illites. This corresponds to the illitization process that occurred after the deposition of rocks, when the Silurian brines infiltrated the deeper Ordovician shale. It was also possible to estimate of porewaters ages.
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Edwards, Cole T. "Carbon, sulfur, and strontium isotope stratigraphy of the Lower-Middle Ordovician, Great Basin, USA: Implications for oxygenation and causes of global biodiversification." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405797089.
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Potot, Cécile. "Étude hydrochimique du système aquifère de la basse vallée du Var : apport des éléments traces et des isotopes (Sr, Pb, O, Ra)." Nice, 2011. http://www.theses.fr/2011NICE4004.
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L’objectif principal de cette étude est d’améliorer les connaissances sur le système aquifère de la basse vallée du Var, principale ressource d’eau potable dans une région soumise à des influences méditerranéennes et alpines. La composition des éléments majeurs et traces, des isotopes de l’O, du Pb et du Sr a été déterminée à différentes périodes hydrologiques dans les eaux du fleuve Var, de ses affluents, de la nappe alluviale de la basse vallée, et des aquifères des calcaires jurassiques et des poudingues pliocènes, qui constituent le substratum des alluvions. Les concentrations mesurées sont souvent proches du fond géochimique naturel, ce qui fournit pour chaque type d’eaux un point de référence de la qualité et permet, grâce à la sensibilité de la mesure des traces, de détecter la moindre pollution émergente. Des pollutions agricoles et / ou domestiques ont été détectées, en particulier dans les eaux des poudingues, ceci même en profondeur. Le fleuve constitue la principale source d’alimentation de la nappe alluviale, essentiellement à l’amont de la vallée. La recharge de la nappe par l’aquifère des poudingues représente 20 % environ, ce qui est inférieur aux estimations précédentes. L’utilisation conjointe des éléments traces et majeurs met en évidence l’hétérogénéité des eaux des poudingues, et permet d’évaluer les proportions de mélange. L’alimentation de la nappe par les calcaires semble faible. La forte influence chimique des évaporites triasiques limite l’utilisation des isotopes du Sr comme marqueur d’origine des eaux. Les isotopes du Pb ont fourni des résultats complexes qui semblent montrer une origine à la fois naturelle et anthropique, cette dernière apparemment liée aux pluies. Les isotopes du Ra ont été utilisés afin d’estimer le temps de parcours dans la nappe alluviale. La faisabilité analytique de la méthode semble acquise. Malgré d’importants échanges avec le milieu traversé, l’utilisation des rapports isotopiques semble s’affranchir de certains processus complexesThe main goal of this study is to improve the knowledge of the Lower Var Valley aquifers, under both Mediterranean and Alpine influences. Majors, trace elements, and O, Sr and Pb isotopes have been analysed under various hydrological conditions in water of the Low Var Valley including the alluvial aquifer, the Var River, its tributaries and groundwaters from Jurassic limestones and Pliocene conglomerates, which are the substrate of alluvia. Concentrations of most majors and trace elements are often close to the natural background, which gives a baseline quality of waters. High sensitivity in trace element measurement may allow to early detect contamination in any water body. Agricultural and / or residential contaminations have been detected in limestone and above all in conglomerate groundwater. The Var River is the main source of water of the alluvial aquifer, especially in upstream part. Conglomerate groundwater inputs stand for about 20 % of alluvial water recharge, which is lower than previously estimated. The use of both major and trace elements gives evidences of high heterogeneity in conglomerate groundwater and leads to estimate the proportions of inputs to the alluvial aquifer. Recharge of the alluvial aquifer by Jurassic limestones seems to be significant. Strong influence of Triassic evaporates in most samples gives limitation to the use of strontium isotopes as tracers of water origin. Pb isotopes gave complex results, which could suggest both a natural origin and an anthropogenic one that could be related to rainwater. Radium isotopes were used to estimate the flow velocity in the alluvial aquifer. Several techniques demonstrate the analytical feasibility of this approach and despite important exchanges with aquifer matrix, the use of isotopic ratios apparently minimizes the effect of complex processes
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Warham, Joseph O. "Mapping biosphere strontium isotope ratios across major lithological boundaries. A systematic investigation of the major influences on geographic variation in the 87Sr/86Sr composition of bioavailable strontium above the Cretaceous and Jurassic rocks of England." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5500.
Full textAbstract:
Strontium isotope analysis has provided archaeologists with an unprecedented opportunity to study the mobility of humans and animals in the past. However, a lack of systematic environmental baseline data has seriously restricted the full potential of the analytical technique; there is little biosphere data available against which to compare measured skeletal data.
This thesis examines the extent to which geographic variation in biosphere 87Sr/86Sr composition can be spatially resolved within the lowland terrain of England, in a geographically and geologically coherent study area. Systematically collected samples of vegetation, stream water and surface soils, including new and archived material have been used. The potential of these sample media to provide reliable estimates of the 87Sr/86Sr composition of bioavailable strontium are evaluated under both high-density and low-density sampling regimes, and against new analyses of local archaeological material.
Areas lying south of the Anglian glacial limit, display a pattern of geographic 87Sr/86Sr biosphere variation (0.7080¿0.7105) controlled by solid geology, as demonstrated by high-density biosphere mapping. Data collected at a wider geographic scale, including above superficial deposits, indicate the dominant influence of re-worked local rocks on the biosphere. These methods have enabled a reclassification of the archaeologically important Cretaceous Chalk domain. Analysis of rainwater and other indicators of atmospheric deposition show that, in this setting, local biosphere variation is not significantly perturbed by atmospheric inputs.
Time-related data from archaeological cattle and sheep/goat tooth enamel suggest that the modern biosphere data can be used to understand livestock management regimes and that these are more powerful than using an average value from the enamel. A more complete understanding of possible patterns of mobility in a group of humans has been achieved through analysis of material from Winchester and comparison with the Chalk biosphere domain.British Geological Survey¿s British University Funding Initiative (BUFI) and the School of Life Sciences at the University of Bradford joint funding.
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Campbell, Catherine E. "Strontium isotopes as tracers of water co-produced with coalbed natural gas in the Powder River Basin, Wyoming." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1404342321&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Thibodeau, Alyson Marie. "Isotopic Evidence for the Provenance of Turquoise, Mineral Paints, and Metals in the Southwestern United States." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/243111.
Full textAbstract:
Lead and strontium isotopes are two powerful tracers that can be used to identify or constrain the provenance of a wide range of archaeological materials, but these two isotopic tracers have been rarely employed to infer the sources of artifacts in the southwestern USA. This dissertation contains four studies that demonstrate how these isotopic systems can address questions about the sources of three types of archaeological materials found in this region: turquoise, lead-based glaze-paints, and metals. The analysis of 116 samples of turquoise from 17 deposits in the southwestern USA reveals that lead and strontium isotopes are robust and sensitive tracers of turquoise at multiple scales. Isotopic variation among turquoise deposits correlates with broad regional differences in the geologic and tectonic setting of the rocks and mineral deposits which host turquoise mineralization. Many turquoise deposits also have unique isotopic signatures that will enable insights into ancient patterns of turquoise acquisition at regional and local levels. To show the utility of these tracers when applied to archaeological turquoise, I use lead and strontium isotopic measurements to establish that the Silver Bell Mountains are the likely source turquoise found at the Redtail site in the Tucson Basin, Arizona, USA. This dissertation also contains new, high-precision isotopic ratios of lead ores (galena and cerrusite) from four mining districts in New Mexico, including the Cerrillos Hills. All districts studied are possible sources of lead used by Pueblo IV communities to produce glaze paints. These new measurements, made by multiple-collector ICP-MS, define the isotopic composition of the ore deposits with greater precision and accuracy than achieved in previous studies, indicating an opportunity to improve interpretations about the provenance of lead in glaze paints. Lead isotopes are also found to be useful tools for identifying lead and copper metal associated with the 1540-1542 Vázquez de Coronado expedition. Lead shot and copper crossbow boltheads from two sites with archaeological evidence for the expedition's presence were determined to share similar or identical lead isotopic ratios. I propose this specific isotopic "fingerprint" can be used to identify other artifacts belonging to the expedition in the Southwest.
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Stallo, Jennifer Rose. "Isotopic Study of Migration: Differentiating Locals and Non-Locals in Tumulus Burials From Apollonia, Albania." Cincinnati, Ohio : University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1186753260.
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Thesis (M.A.)--University of Cincinnati, 2007.Title from electronic thesis title page (viewed Oct. 8, 2007). Includes abstract. Keywords: strontium, isotopes, migration, Albania, Apollonia. Includes bibliographical references.
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McCall, Ashley E. "The Relationship of Stable Isotopes to Late Woodland and Fort Ancient Agriculture, Mobility, and Paleopathologies at the Turpin Site." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367924972.
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Porter, Courtney. "Solute Inputs to Soil and Stream Waters in a Seasonally Snow-Covered Mountain Catchment Determined Using Ge/Si, ⁸⁷SR/⁸⁶SR and Major Ion Chemistry: Valles Caldera, New Mexico." Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/265377.
Full textAbstract:
Weathering releases lithogenic elements to soil and stream waters that support life in catchment ecosystems. Seasonal and inter-annual variations in hydrologic conditions change subsurface flowpaths, modifying the influence of weathering on stream waters. This study, over two climatically variable years, determined seasonal and inter-annual changes in solute sources to streams using a multi-tracer approach including major cations, strontium isotopes, germanium (Ge)/silica ratios, carbon species, and trace metals. Stream water cations display constant concentrations although discharge response was highly variable, suggesting that there is a consistent subsurface water supply. However, Sr isotope ratios, and concentrations of Ge, Fe, Al, and dissolved organic carbon, which originate from shallow soil waters, increase with the hydrograph during a wet winter snowmelt. This indicates that during a year with a thick snowpack, stream waters contain components of both shallow soilwater and groundwater during snowmelt, whereas during all other times groundwater contributes predominantly to the stream.
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Warham, Joseph Olav. "Mapping biosphere strontium isotope ratios across major lithological boundaries : a systematic investigation of the major influences on geographic variation in the 87Sr/86Sr composition of bioavailable strontium above the Cretaceous and Jurassic rocks of England." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5500.
Full textAbstract:
Strontium isotope analysis has provided archaeologists with an unprecedented opportunity to study the mobility of humans and animals in the past. However, a lack of systematic environmental baseline data has seriously restricted the full potential of the analytical technique; there is little biosphere data available against which to compare measured skeletal data. This thesis examines the extent to which geographic variation in biosphere 87Sr/86Sr composition can be spatially resolved within the lowland terrain of England, in a geographically and geologically coherent study area. Systematically collected samples of vegetation, stream water and surface soils, including new and archived material have been used. The potential of these sample media to provide reliable estimates of the ⁸⁷Sr/⁸⁶Sr composition of bioavailable strontium are evaluated under both high-density and low-density sampling regimes, and against new analyses of local archaeological material. Areas lying south of the Anglian glacial limit, display a pattern of geographic ⁸⁷Sr/⁸⁶Sr biosphere variation (0.7080-0.7105) controlled by solid geology, as demonstrated by high-density biosphere mapping. Data collected at a wider geographic scale, including above superficial deposits, indicate the dominant influence of re-worked local rocks on the biosphere. These methods have enabled a reclassification of the archaeologically important Cretaceous Chalk domain. Analysis of rainwater and other indicators of atmospheric deposition show that, in this setting, local biosphere variation is not significantly perturbed by atmospheric inputs. Time-related data from archaeological cattle and sheep/goat tooth enamel suggest that the modern biosphere data can be used to understand livestock management regimes and that these are more powerful than using an average value from the enamel. A more complete understanding of possible patterns of mobility in a group of humans has been achieved through analysis of material from Winchester and comparison with the Chalk biosphere domain.
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Sutcliffe, Nadine C. "Strontium stable isotope behaviour accompanying melting and magmatism in the Earth-Moon system." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:826ae843-3115-4a3e-975a-f6306f923d4e.
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This thesis concerns the application of a new technique for measuring the stable isotopes of Sr, specifically pertaining to mass dependent fractionation in high temperature processes on the Earth and Moon. Processes such as mantle melting and differentiation on Earth and the formation of the Lunar Magma Ocean are investigated by the application of a double-spike TIMS method to terrestrial and lunar material to obtain high-precision 87Sr/86Sr, 88Sr/86Sr and 84Sr/86Sr data. Measurements of mantle-derived mafic material provide insights into the 88Sr/86Sr composition of the silicate mantle. Ocean Island Basalts possess restricted δ88Sr compositions, whilst Mid-Ocean Ridge Basalts from the Pacific, Atlantic and Indian ridges reveal variations in δ88Sr, the majority of which is seen within the FAMOUS section of the Mid-Atlantic Ridge. These variations are attributed partly due to the effects of plagioclase crystallisation and partly due to mantle source heterogeneity. Analyses of mineral separates from three different igneous systems provide an understanding of δ88Sr fractionation at a mineral-scale. The possibility of δ88Sr fractionation as a result of magmatic differentiation has also been assessed, and found to occur between the basalt and rhyolitic end-members of the Icelandic Hekla suite. Variations in the 87Sr/86Sr ratios of these rocks are also found, and considered most likely to be due to contamination. Analyses of lunar rocks indicate that the highland suite appears to be relatively uniform in δ88Sr, whilst significant fractionation to light δ88Sr compositions occurs in the mare basalts. Such variations are thought to be associated with the crystallisation of plagioclase during the differentiation of the lunar magma ocean. Lastly, precise 87Rb/86Sr and 87Sr/86Sr data yield a model age for the Moon of 4.523 ± 0.019 Ga.
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Wilson, Jessica Norman. "Stable Isotopes and Trace Elements in Tooth Enamel Bioapatite: Effects of Diagenesis and Pretreatment on Primary Paleoecological Information." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4965.
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The geochemical analysis of bioapatite in vertebrate skeletal tissues is an important tool used to obtain ecological information from fossil animals. An important consideration when conducting stable isotope and trace element analyses is obtaining biogenic information that has been unaffected by diagenetic processes.
A two-step pretreatment procedure is commonly used remove diagenetically altered material by removing organic material, via an oxidation reaction with H2O2 or NaOCl, and secondary carbonate, via dissolution in dilute acetic acid, from bioapatite. While much work has been done to determine the efficacy of the pretreatment process, little research has been conducted to determine the potential effects of this process on the oxygen isotope composition of enamel bioapatite. A comparison between δ18O values of fossil enamel treated with 18O-depleted (δ18O = -10.0 / V-SMOW) and 18O-enriched solutions (δ18O = +16.4 / V-SMOW). On average, samples treated with 18O-enriched solutions had δ18O values at least 0.4 / V-PDB more positive than samples treated with 18O-depleted solutions. These results suggest that the isotopic composition of solutions used in the pretreatment process can significantly affect the δ18O values of fossil enamel prior to isotopic analysis.
Diagenetic alteration can potentially be assessed using the linear relationship between δ18O values of the carbonate and phosphate components of bioapatite, as any deviation from a slope of 1 suggests alteration. Comparing the relationship between δ18Op and δ18Oc for fossil mammals from the Hadar Formation suggests that this method is successful at identifying samples that are significantly different from the remaining samples due to diagenetic alteration. The relationship between δ18Oc and δ18Op for the majority of sampled fossils from the Hadar Formation has a slope very close to 1 with an average offset, and apparent fractionation factor, between δ18Oc and δ18Op consistent with modern mammals. Therefore, it is likely that many of the fossil mammals sampled from the Hadar Formation retain in vivo δ18O values relating to the δ18O value of the water they consumed.
The reliability of paleodietary reconstructions using trace element ratios (notably Sr/Ca and Ba/Ca) is strongly dependent on the preservation of biogenic trace element concentrations. Although most trace element ratio research relies on bone bioapatite, enamel has a better preservation potential and may successfully preserve biogenic trace element relationships. An analysis of Sr/Ca, Ba/Ca, and Zn/Ca ratios indicates that, despite rare earth element concentrations greater than the 1ppm observed in modern enamel, mammals from the Hadar and Busidima formations potentially reflect feeding strategies observed in modern counterparts, i.e. grazers have higher Sr/Ca and Ba/Ca ratios than browsers and omnivores
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Garcia, Ramon. "Microwave-assisted decomposition of environmental samples, and the analysis of plutonium and radiostrontium." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/17233.
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Drahotusky-Bruketa, Luka. "Strontium isotope ratio analysis (87Sr/86Sr) in the post-classical population of La Selvicciola (Viterbo, Italy, VI-VIII century CE)." Master's thesis, Universidade de Évora, 2020. http://hdl.handle.net/10174/29167.
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Abstract:
The Longobard cemetery of La Selvicciola, located in the province of Viterbo, Italy, has been the
subject of systematic excavations since 1982. The archaeological artefacts recovered from the
cemetery suggest that it was used from the end of the VI century to the beginning of the VIII
century CE. To date, the pattern of occupation of the cemetery by the Longobards and the relation
between these invading peoples and the earlier roman population is still to be fully assessed. The thesis
intends to offer a description of mobility patterns observed in the Longobard burials employing
strontium isotope ratio (87Sr/86Sr) measured in human and animal bone and dental enamel. Data obtained are
compared with bioarchaeological, geological and historical context. This study aims to understand
the cultural identity of individuals, firstly by determining if reconstructed isotopic signatures
support the existing historical, archaeological and anthropological information about these
skeletons, and secondly by identifying any distinguishable trends between cultural groups which
can be linked to status or behavior.
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Gouldey, Jeremy C. "Strontium and Carbon Isotope Stratigraphy of the Llandovery (Early Silurian): Implications for Tectonics and Weathering." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1221528660.
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Noche-Dowdy, Liotta Desiree. "Multi-Isotope Analysis to Reconstruct Dietary and Migration Patterns of an Avar Population from Sajópetri, Hungary, AD 568-895." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5547.
Full textAbstract:
The Avar were nomadic people from Central Asia who migrated into the Carpathian Basin in Central-Eastern Europe during the mid to late Migration Period (AD 568 - 895). Archaeological evaluation of grave goods and documentation of mortuary practices have been the primary means of understanding the Avar. However, this approach has largely neglected skeletal and biochemical analysis, in particular as these approaches relate to the biological variation, ancestry, and dietary patterns of the Avar.
There remains debate as to whether disparities existed among the socially stratified Avar population of ancient Hungary. It is argued by some that these disparities existed and were the result of differential access to nutritional resources. This hypothesis was tested using the unique properties of isotopes and their chemical signatures. In so doing, the qualitative work on the grave goods was augmented by an additional, quantifiable line of evidence.
To investigate social stratification among the Avar population, the techniques of chemical multi-isotope and osteological analysis were employed. Multi-isotopic analyses can be done on stable isotopes (carbon, nitrogen, and oxygen) and on the heavy isotopes (strontium and lead). The particular stable isotopes examined were carbon (δ13C), nitrogen (δ15 N), and oxygen (δ18O). The heavy isotopes analyzed were strontium (87Sr/86Sr) and lead (206Pb/204Pb). Stable isotope analysis as well as ratio analysis of the heavy isotopes strontium (87Sr/86Sr) and lead (206Pb/204Pb) are well-established analytical chemistry methods for examining diverse aspects of diet and mobility through specific geographic regions. The analysis was performed on samples derived from well-preserved tooth enamel and bones.
Reconstructing migration and dietary patterns at the Sajópetri cemetery site has helped estimate variability among social groups and between sexes in this population at the time of the Migration Period. Results of the heavy isotope analysis revealed that the Avar population were non-locals to the region, and the stable isotope analysis demonstrated that there was little variation between social groups with slightly higher variation between sexes. This research provides an empirical and analytical framework for further research into migration patterns and social class dynamics of late prehistoric Hungry. This study also adds existing research possibilities to the on-going biogeochemical studies conducted throughout Europe.
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Hess, Emily Nancy. "Strontium, Lead, and Oxygen Isotopic Signatures of Mid-Miocene Silicic Volcanism in Eastern Oregon." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/2079.
Full textAbstract:
Widespread, mid-Miocene rhyolite volcanism of eastern Oregon that are coeval or slightly postdate flood basalts of the Columbia River Basalt Province allows for mapping crustal domains using radiogenic and stable isotopes. Rhyolites are thought to be derived in large part by partial melting of the crust and thus yield direct information on the composition of the crust. Silicic volcanism is expressed in the form of numerous domes and tuffs exposed over a wide area (~300 km in N-S dimension and ~200 km in E-W dimension) west of the presumed craton boundary, which runs parallel but mostly east of the Oregon-Idaho state border as delineated by geophysical characteristics and isotopic transitions, including the 87Sr/86Sri = 0.7060 line (MSL) and 87Sr/86Sri = 0.7040 (CSL).
87Sr/86Sri of twenty-seven silicic units are variable and some are high. Sr isotopic ratios are inconsistent with the location of the traditional MSL and CSL boundaries. A primary control on the 87Sr/86Sri isotope variations may reflect changes in the crustal make-up of Paleozoic accreted terranes of a particular area rather than arising from a westward-dipping decollement that moved cratonic lithosphere below accreted terranes in eastern Oregon. A secondary control on observed isotopic ratios may be related to the amount and composition of basalt involved in the generation of rhyolites. This could lead to higher or lower 87Sr/86Sri relative to the surrounding crust because de facto coeval mafic magmas of the Columbia River Basalt Group have a wide range of Sr isotopic signatures.
While Pb isotope data is incomplete for all samples of this study, the available data indicate a significant range in Pb isotopes. Yet, data of individual regions tend to plot close to one another relative to the entire data distribution. Comparison of samples from this study in a more regional view indicates the samples generally fall within the previously defined lead isotope boundaries of the main-phase Columbia River Basalt Group lavas.
[lowercase delta]¹⁸O values range from below 2 parts per thousand to above 9 parts per thousand. In addition, there is a crude trend of rhyolites having lower [lowercase delta]¹⁸O and more radiogenic ⁸⁷Sr/⁸⁶Sr[subscript i] ratios. The lowest oxygen ratios (< 2 parts per thousand) are found in rhyolites ~80 km west of the cratonic margin, potentially reflecting remelting or assimilation of hydrothermally altered crust. Low [lowercase delta]¹⁸O of selected rhyolite flows cannot be explained by remelting of Cretaceous plutons of the Idaho Batholith and appear irreconcilable with remelting of altered silicic rocks at centers of multiple, confocal caldera cycles- both processes that have been proposed to explain low [lowercase delta]¹⁸O of rhyolites of the Snake River Plain-Yellowstone area.
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Widanagamage, Inoka Hasanthi. "STABLE STRONTIUM ISOTOPE FRACTIONATION IN ABIOTIC AND MICROBIALLY MEDIATED BARITE IN MODERN CONTINENTAL SETTINGS." Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1445344122.
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Pritchard, Jodie Lee, and jodie_pritchard@hotmail com. "Dynamics of stream and groundwater exchange using environmental tracers." Flinders University. School of Chemistry, Physical & Earth Science, 2006. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20060407.122526.
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Regions of surface water and groundwater exchange are major sites for the transfer and transformation of solutes and nutrients between stream and subsurface environments. Conventional stream and groundwater exchange investigations are limited by methodologies that require intensive field investigations and/or the set-up of expensive infrastructure. These difficulties are exacerbated where hydraulic gradients are very low and stream discharge highly variable. This thesis uses a suite of environmental tracers (Cl-, Rn-222, H-2 & O-18, Sr-87/Sr-86) to characterise the extent of stream and groundwater exchange between a sand bed stream and adjacent alluvial aquifer in a subtropical catchment (the Wollombi Brook) of eastern Australia. The aims were to identify sources and relative contributions of different sources of groundwater to stream discharge and specifically to improve the methodology of using Rn-222 to obtain quantitative estimate of groundwater fluxes.
The sensitivity of the Rn-222 technique for identifying groundwater discharge based on the Rn-222 concentration in stream water was improved via an iterative numerical approach to account for Rn-222 loss from stream water via turbulent gas exchange and radioactive decay. Optimal distances between stream sampling points for defining the magnitude of groundwater discharge to stream flow based on Rn-222 concentrations in stream water is a function of average stream velocity and water depth. The maximum allowable distance between sampling points for determining the magnitude of groundwater discharge to the Wollombi Brook was 2 km. This work showed that groundwater discharged to all reaches of the Wollombi Brook during baseflow and flood recession conditions. Alluvial groundwater contributed less than 30% of water to stream flow in the mid Wollombi Brook catchment.
Dilution of steady-state Rn-222 concentrations measured in transects from the stream to the alluvial sediments showed that significant surface water and groundwater exchange occurs even when gradients between surface water and groundwater are low. Lateral stream water influx to the adjacent alluvial aquifer was more extensive in the lowland areas of the Wollombi Catchment during low flow than flood recession conditions. Extensive stream water influx to the adjacent alluvial aquifer occurs contrary to the net direction of surface water and groundwater flux (as indicated by hydraulic gradients toward the stream channel). The rate of stream and groundwater exchange within the adjacent alluvial aquifer appears to be greatest during baseflow conditions. Fresh alluvial groundwater appeared to provide a buffer against higher salinity regional groundwater discharge to the alluvial aquifer in some reaches of the Wollombi Brook catchment. Pumping of the alluvial aquifer and diversions of surface water may jeopardise the water quality and volume of the alluvial aquifer and induce water flow from the regional aquifer toward the stream, potentially salinising the fresh alluvial aquifer and subsequently the stream.
The change in the Cl- concentration and the variation in slope of the deuterium � oxygen-18 line between consecutive stream sampling points could be used to differentiate between regional and alluvial groundwater discharge to stream flow. Incorporating this information with three-component end-member mixing using [Sr2+] and Sr-87/Sr-86 showed that stream and alluvial groundwater exchange within the stream channel was highest in the lowland floodplains during low flow conditions. The least stream and alluvial groundwater exchange occurred in the low streambed gradient mid reaches of the Wollombi Brook regardless of stream stage. The greatest difference in the degree of stream and alluvial groundwater exchange between high and low stream stages occurred in the lowland floodplains of the Wollombi Brook.
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Delattre, Emmanuel. "Phytoremédiation de déchets chlorurés en respect de la biodiversité : Application au traitement des effluents industriels et des sédiments marins." Thesis, Nîmes, 2020. https://tel.archives-ouvertes.fr/tel-03178443.
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Deux types de déchets salins ont été traités par la voie de la phytoremédiation : des effluents industriels et des sédiments marins. Le potentiel de trois espèces aquatiques, Phragmites australis, Typha latifolia et Juncus maritimus, pour traiter la charge en ions Cl- a été caractérisé pour différents stades de maturité au travers d’essais en laboratoire. Ces espèces ont montré d’excellentes capacités d’adaptation aux milieux chlorurés et en particulier pour un stade de croissance mature (plants âgés d’un an). La phytoremédiation des déchets considérés semble possible avec des abattements significatifs, que ce soit pour les effluents (50-95 % d’abattement en 40 jours) ou les matrices solides (5-30 % d’abattement en 80 jours). Les abattements mesurés sur les essais sur effluents s’expliquent principalement par des mécanismes de sorption des ions Cl-. Les végétaux ne jouant alors quant à eux qu’un rôle mineur via l’exportation de leur matière verte. Une expérimentation à plus grande échelle sur des sédiments marins dragués spécifiquement pour cette étude a été menée. Sur la période expérimentale étudiée, aucune croissance des végétaux n’a pu être observée ayant pour conséquence aucun effet de remédiation. Plusieurs causes ont été mises en évidence ou présupposées : la granulométrie des sédiments (vase), la canicule de 2019 ou encore la présence d’autres contaminants (SO42-, métaux/métalloïdes). Ces essais ont néanmoins permis de montrer que la phytoremédiation en procédé unique de gestion des sédiments marins fraichement dragués n’est pas adaptée. De nouveaux systèmes de phytoremédiation doivent donc être étudiés sur ces sédiments en combinaison avec différents procédés tels que le lessivage, l’osmose inverse ou l’évaporation. De plus, afin d’optimiser les capacités épuratoires des végétaux dans un procédé de phytoremédiation, il est nécessaire d’employer des espèces acclimatées et donc locales. Aucune méthode de traçage de l’origine géographique des végétaux aquacoles n’est aujourd’hui préconisée. Un outil de traçage basé sur le rapport isotopique du strontium (87Sr/86Sr) a été étudié vis-à-vis des différentes fraudes pouvant être observées dans ce secteur. La faisabilité de discriminer des aires géographiques a été évaluée par la comparaison de la signature isotopique de différentes productions à travers le monde (France, Allemagne, Hongrie, Chine). La caractérisation du cycle biogéochimique du Sr pour les plantes aquatiques a permis de mettre en évidence la contribution majeure de l’eau d’irrigation ainsi que celle des pratiques agricoles, justifiant des rapports isotopiques propres aux productions. La stabilité temporelle de cet outil a été confirmée au travers de la reculture de végétaux étrangers dans des conditions locales. Ainsi, les isotopes stables du strontium se révèlent être un outil précieux pour certifier l’origine géographique des végétaux aquatiques et mettre en évidence les fraudes communément observées dans ce domaineTwo types of saline waste were treated by phytoremediation: industrial effluents and marine sediments. The potential of three aquatic species, Phragmites australis, Typha latifolia and Juncus maritimus, to treat the Cl-ion contamination was characterised for different stages of maturity through laboratory tests. These species showed excellent adaptation to saline environments and in particular for a mature growth stage (one-year-old plants). Phytoremediation of the waste considered seems possible with significant reductions, both for effluents (50-95% reduction in 40 days) and solid matrices (5-30% reduction in 80 days). The remediation rates measured in the effluent tests are mainly explained by Cl- ion sorption mechanisms. Plants then play only a minor role via the export of their green matter. A larger scale experiment was carried out on marine sediments dredged specifically for this study. Over the experimental period studied, no plant growth was observed, resulting in no remedial effects. Several causes were identified or presupposed: the granulometry of the sediment (silt), the heat wave of 2019 or the presence of other contaminants (SO42-, metals/metalloids). Nevertheless, these tests have shown that phytoremediation as a single process for managing freshly dredged marine sediments is not suitable. New phytoremediation systems must therefore be studied on these sediments in combination with different processes such as leaching, reverse osmosis or evaporation. Moreover, in order to optimise the epuration capacities of plants in a phytoremediation process, it is necessary to use acclimatised and therefore local species. No method for tracing the geographical origin of aquaculture plants is currently recommended. A tracing tool based on the strontium isotopic ratio (87Sr/86Sr) has been studied in relation to the various frauds that can be observed in this sector. The feasibility of discriminating between geographical areas was assessed by comparing the isotopic signature of different productions throughout the world (France, Germany, Hungary, China). The characterisation of the biogeochemical cycle of Sr for aquatic plants highlighted the major contribution of irrigation water as well as that of agricultural practices, justifying the isotope ratios specific to the productions. The temporal stability of this tool was confirmed through the recultivation of foreign plants in local conditions. Thus, the stable isotopes of strontium are proving to be a valuable tool for certifying the geographical origin of aquatic plants and highlighting the frauds commonly observed in this field
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Goad, Gennifer M. "High-Precision Lead Isotope Analysis on Modern Populations to Determine Geolocation Reliability." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7508.
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Forensic anthropologists increasingly use chemical isotope analysis in the investigation of unidentified human remains, as biochemical georeferencing continually improves with the development of modern reference data of known origins. Isotope variations in trace elements such as strontium (Sr) and lead (Pb) in human teeth are some of the most useful indicators of past domicile in archaeological research and thus have high potential for modern, forensic applications. In this study, high-precision lead isotope analysis was conducted on 63 modern human teeth, which were previously analyzed for strontium isotopes. The results present new lead isotope data for the following countries: United States (n=34), Colombia (n=9), Haiti (n=5), Cape Verde (n=3), Morocco (n=2), El Salvador (n=2), Guatemala (n=2), Honduras (n=2), Jamaica (n=1), Dominican Republic (n=1), Albania (n=1), and United Kingdom (n=1). In addition, the lead and strontium isotope data of 23 modern human teeth from individuals born in Holland, eight teeth from individuals born in Bulgaria, and 26 teeth from individuals born in the U.S. are extracted from the literature to supplement the data analysis. Exploratory data analysis, nonparametric Kruskal-Wallis tests, and one-way analysis of variance (Scheffe post hoc) are conducted using IBM SPSS® Statistics 24 to test for regional variation. Several trends are observed in the lead isotope data that may be relevant to modern forensic contexts involving unidentified human remains: Individuals from the northeast U.S. have relatively distinct 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb ratios when compared to individuals from the rest of the U.S. European and American individuals can be easily distinguished from each other using 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb ratios. Central American individuals have significantly lower 87Sr/86Sr ratios than North American individuals, and these groups can be easily distinguished using lead versus strontium scatterplots. Colombian individuals have significantly lower 87Sr/86Sr ratios than North American individuals, and these groups can be easily distinguished using lead versus strontium scatterplots. Caribbean individuals have significantly lower 87Sr/86Sr isotope ratios than individuals from the northeast U.S., and these groups can be easily distinguished using lead versus strontium scatterplots.
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Hajj, Fadi. "Utilisation des isotopes stables et radiogéniques du strontium pour tracer la provenance des bois : application à des épaves sous-marines." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0334.
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Au début des temps modernes (16ème - 18ème siècles), la construction de grands navires était primordiale pour le développement des rencontres culturelles dans ce qui est devenu l'âge de la découverte et de l'expansion européenne. L’Espagne était une des grandes puissances de l’époque. Le projet européen « ForSEAdiscovery » cherche dans ce contexte à répondre aux questions clés suivantes : les ressources forestières ibériques de l’époque soutenaient-elles la demande croissante de bois, ou bien ce bois était-il importé d’autres pays ? Si ces bois ne provenaient pas de l’Espagne, comment les réseaux de commerce étaient-ils organisés ? Ce projet aborde ces questions à travers un programme de recherche multidisciplinaire et innovant pour améliorer la compréhension de notre passé historique et de notre patrimoine culturel, et développer notre connaissance sur l'utilisation passée des ressources en bois pour la construction navale. L'objectif de cette thèse, qui s’insère dans ce projet, est d’identifier la provenance des bois utilisés dans la construction navale ibérique en utilisant des traceurs géochimiques. L’hypothèse est que les arbres se développant sur des roches et des sols contrastés possèdent des signatures géochimiques spécifiques héritées des roches. Les signatures isotopiques en strontium (87Sr/86Sr) peuvent notamment être des indicateurs de provenance géographique. Dans ce contexte, la démarche suivie dans la thèse a consisté à caractériser la signature isotopique en Sr dans des bois d'épaves de bateaux et dans les bois d’arbres actuels, les sols et roches prélevés dans les principaux peuplements forestiers espagnols pointés comme lieux de production des bois entre le 16ème - 18ème siècles. Les signatures en δ88/86Sr, traceur peu connu encore, ont également été caractérisées dans les échantillons. Les types et les âges des roches ont été caractérisés et les liens entre les rapports isotopiques 87Sr/86Sr et δ88/86Sr dans les roches, sols et arbres ont été étudiés sur les sites espagnols échantillonnés. La signature locale des sites espagnols potentiels de provenance de bois a été déterminée. Nos résultats mettent en évidence que le rapport isotopique 87Sr/86Sr dans les arbres reflète la signature de la fraction échangeable des sols sur lesquels ils croissent alors que le δ88/86Sr est affecté par le fractionnement, les isotopes légers (86Sr) étant préférentiellement incorporés dans les arbres laissant la fraction échangeable du sol enrichie avec les isotopes lourds (88Sr). Ce fractionnement observé pour les chênes, n’est pas marqué dans le bois des pins suggérant que le fractionnement isotopique durant le transfert du Sr entre le sol et l’arbre est dépendant de l’espèce. La contamination des bois d’épaves par les éléments marins a été identifiée. Le Sr marin se retrouve notamment sous forme adsorbée ou dans la structure des minéraux précipités dans les bois immergés. Différentes expériences d’extractions ont été testées et un protocole adapté a été développé pour extraire les éléments marins et retrouver la signature originelle du bois archéologique. Nous avons réussi à valider un protocole d’extraction et retrouver la signature originelle d’un échantillon de bois d’épave. Ce résultat souligne le potentiel et l’importance d’une nouvelle méthode combinant 87Sr/86Sr et δ88/86Sr pour des futures études de provenance de bois ou autres matériaux. Cependant, nos résultats indiquent également que beaucoup de nos échantillons de bois archéologiques n’ont pas conservé leur Sr originel. Partant de ce constat, des préconisations sont proposées pour améliorer la possibilité d’utilisation de ce traceur dans les études futures de provenance de bois archéologiques sous-marinsIn the Early Modern Age (16th - 18th centuries), the construction of ocean-going ships was paramount to the development of cultural encounters in what became the Age of Discovery and European expansion. Spain was one of the biggest forces of that time. The European project “ForSEAdiscovery” seeks answers in this context to the following key questions: Could Spanish forest resources sustain the increasing demand of timber, or were the wood imported from elsewhere? If Spanish forests were not the only wood supplier, how were the trade networks organized? This project will address these questions through a multidisciplinary and innovative training research program to improve the understanding of our historical past, our cultural heritage, and our knowledge of the use of resources for shipbuilding. The objective of this PhD thesis, taking part of this project, is to identify the provenance of the Iberian shipbuilding wood using geochemical tracers. The hypothesis is that trees growing on contrasted rocks and soils have specific geochemical signatures, which can be an indicator of geographic provenance. In this context, the Sr isotopic signature (87Sr/86Sr) was characterized in shipwreck wood samples and wood from living trees, soils and rocks collected from the Spanish forest stands indicated as potential source of wood between the 16th - 18th centuries. The δ88/86Sr signatures were also characterized in the samples. The rock types and ages were characterized at the selected sites and the link between the 87Sr/86Sr and δ88/86Sr in rocks, soils and trees was studied on the sampled Spanish sites. The local signature of Spanish potential sites was determined for provenance of wood. Our results indicate that 87Sr/86Sr isotope ratios in trees reflect the signature of the corresponding soil exchangeable pool while δ88/86Sr was shown to be affected by mass-dependent fractionation with trees taking up lighter (86Sr) isotopes, leaving the soil exchangeable pool enriched with the heavier isotopes (88Sr). This fractionation observed for oak trees, was not found in pines suggesting that the isotopic fractionation during tree uptake is species dependent. The contamination of wood from shipwrecks by seawater elements was identified. Marine Sr was found to be adsorbed on the wood or included in the precipitated minerals in the waterlogged wood. Several extraction experiments were tested and an adapted protocol was developed to extract the seawater elements and retrieve the original signature of the archaeological wood. We succeeded to validate an extraction protocol and retrieve the original signature of one wood sample. This result underline the potential and importance of a new method combining 87Sr/86Sr and δ88/86Sr values for future provenance studies on wood or other materials. However, our results also indicated that most of our shipwreck wood samples did not conserve their original Sr. Therefore, preconizations were suggested in order to extend the use of this tracer in future provenance studies on archaeological wood from shipwrecks
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Dogramaci, Shawan Shawket. "Isotopes of sulphur, oxygen, strontium and carbon in groundwater as tracers of mixing and geochemical processes, Murray Basin, Australia /." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phd654.pdf.
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Chiquet, Arnaud. "Géochimie isotopique des calcrètes." Aix-Marseille 3, 1999. http://www.theses.fr/1999AIX30024.
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Nous avons utilise les compositions isotopiques du sr, o, c, u et th pour etudier des calcretes (sols calcaires) developpees sur granite en provenance du centre de l'espagne (tolede) et du maroc atlantique (sidi ifni-agadir). Cette approche isotopique pluri-elementaire visait a : 1) preciser le mode de mise en place et les conditions bioclimatiques dans lesquelles ces carbonates ont ete generes, 2) identifier l'origine du calcium accumule et quantifier les apports, et 3) dater ces carbonates pedologiques. Au niveau de la calcrete espagnole, nous avons mis en evidence un remplacement iso-volumique du granite altere par la calcite. La difference de compositions isotopiques en sr obtenue entre la calcite et les mineraux du granite suggere que plus de 90% du calcium accumule dans le sol provient de retombees atmospheriques seches et/ou humides mobilisees lors de la saison humide. Les compositions isotopiques en oxygene et carbone sont compatibles avec les temperatures et taux de production de co 2 du sol du debut de la periode seche. Ainsi, l'alternance climatique saisonniere et la presence d'une source de calcium meme allochtone constitueraient des parametres majeurs controlant la genese des calcretes. La mesure du desequilibre u/th sur ces memes carbonates donne un age compris entre 40 et 270 ka, soit du meme ordre de grandeur qu'un cycle climatique. Les compositions isotopiques en sr des calcretes du maroc atlantique et du centre de l'espagne sont identiques ce qui suggere une source commune, dont la composition est caracteristique du reservoir marin quaternaire. Si l'on couple l'augmentation de l'activite eolienne au moment des maxima glaciaires a nos resultats, on peut penser que les plates-formes carbonatees exondees lors des periodes de bas niveau marin ont pu constituer une source importante de ca aux sols, qui, perennisee par des conditions climatique favorables aurait donne lieu a de fortes accumulations absolues dans les zones semi-arides.
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Reynolds, Amanda Christine. "Geochemical Investigations of Mineral Weathering: Quantifying Weathering Intensity, Silicate versus Carbonate Contributions, and Soil-Plant Interactions." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/194448.
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This study is the geochemical examination of mineral weathering and its path from hinterland, through sediment deposition and pedogenesis, to its dissolution and eventual uptake into plants or precipitation as carbonate minerals. The three papers examine the rate and character of carbonate and silicate mineral weathering over a wide range of climatic and tectonic regimes, time periods, and lithologies, and focus on very different questions. Examination of the 87Sr/86Sr ratios of architectural ponderosa pine in Chaco Canyon, New Mexico confirms a societally complex style of timber procurement from the 10th to the 12th centuries. In El Malpais National Monument, New Mexico, we measured the 87Sr/86Sr ratios in local bedrock and soils and compared them to the leaf/wood cellulose of four conifers (Pinus ponderosa, Pinus edulis, Juniperus monosperma, Juniperus scopulorum), a deciduous tree (Populus tremuloides), three shrubs (Chrysothamus nauseosus, Fallugia paradoxa, Rhus trilobata), and an annual grass (Bouteloua gracilis) and a lichen (Xanthoparmelia lineola). We found that plant 87Sr/86Sr ratios covaried with variations in plant physiognomy, life history, and rooting depth. In addition, the proportion of atmospheric dust and bedrock mineral contributions to soil water 87Sr/86Sr ratios varied predictably with landscape age and bedrock lithology. On the Himalayan floodplain, soils and paleosol silicate weathering intensities were measured along a climatic transect and through time. Overall, carbonate weathering dominates floodplain weathering. But, periods of more intense silicate weathering between 9 - 2 Ma, identified in soil profile and in the 87Sr/86Sr ratios of pedogenic carbonates, appear to be driven by changes in tectonic, rather than climatic, regime. All three papers are good examples of how 87Sr/86Sr isotopic tracer studies can shed light on pedogenic formation rates and internal processes. The complexity of each system warns against generalizations based on just one locale, one species or lithology, or a few isotopic ratios.
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Visser, Gledus. "The application of Sr-spec resin in the analysis of 90Sr in effluent and environmental samples at KNPS." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2327.
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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016.Radiostrontium (90Sr and 89Sr) has been released to the environment by global fall-out following atmospheric nuclear explosions, by waste discharges and fall-out from the Chernobyl. 89Sr, with a half-life of 50.5 days, quickly decays to undetectable levels, while 90Sr is radiobiologically more important because of its longer half-life of 28.78 years, and because it behaves chemically similar to Ca, and accumulates in bones and teeth. Cost effective and relatively simple procedures for determination of radiostrontium are desirable. An accurate determination of radionuclides from various sources in the environment is essential for assessment of the potential hazards and suitable countermeasures both in case of accidents, authorised releases and routine surveillances. Reliable radiochemical separation and detection techniques are needed for accurate determination of alpha and beta emitters. Rapid analytical methods are needed in case of an accident for early decision-making. At the Koeberg Nuclear Power Station (KNPS), 90Sr analysis are performed on liquid effluent samples making use of the traditional fuming nitric acid method, and subsequent counting of particulate samples on an alpha/beta proportional counter. This method is often at times very time – consuming, and involves many precipitation steps. The use of fuming nitric acid is also very dangerous and could lead to severe personnel injuries in the event of an accident. This project focussed on the application of Sr-Spec resin in the analysis of 90Sr. This work presents the methods for 90Sr analysis for both effluent samples as well as environmental samples. This research also focussed on the calibration of the different radiometric instruments, which are the Liquid Scintillation Counter, the Alpha/Beta Counter as well as the Gamma Detector.
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MARCHINA, Chiara. "Geochemical and isotopic investigation on the Po river waters from Monviso sources to its Delta: natural and anthropogenic components." Doctoral thesis, Università degli studi di Ferrara, 2015. http://hdl.handle.net/11392/2389012.
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Quinn, Carolyn J., and n/a. "Stable isotopes and diet : indications of the marine and terrestrial component in the diets of prehistoric populations from New Zealand and the Pacific." University of Otago. Department of Anthropology, 1990. http://adt.otago.ac.nz./public/adt-NZDU20070601.115004.
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The importance of marine versus terrestrial foods in prehistoric Pacific and New Zealand diets, and the adaptation of the Polynesian diet to new enviroments, is examined through the analysis of the ratios in human bone of the stable isotopes of carbon, nitrogen and sulphur. In particular, this study seeks to obtain quantitative information which could provide answers to five main questions, relating to the subsistence focus of the early Lapita colonists in the Pacific, the significance of suger cane in the diets of early Pacific populations, the proportions of reef versus open ocean and terrestrial versus marine foods in these diets, and the identification of populations with pronounced marine or pronounced terrestrial diets.
One hundred and nineteen samples of human bone from 13 sites throughtout the Pacific and New Zealand were processed. Nitrogen values were obtained directly from bone powder, while carbon values were determined from collagen produced by digesting bone powder in phosphoric acid. Sulphur evaluations were determined from a BaSo⁴ precipitate, produced after combustion of the collagen samples in a Parr bomb.
Interpretation of results is approached from a comparative point of view, which enables the proportions of marine and terrestrial foods in the diets of each study group to be assessed in relation to the diets of all the other groups. Additional information on the composition of the diets is gained by comparing the stable isotope values obtained in this study with published values of other human populations, and of marine and terrrestrial plants and animals.
The potential of stable isotope analysis to identify the composition of prehistoric New Zealand and Pacific diets is confirmed. A unique marine adaptation is revealed from the analysis of the Chatham Islands Moriori who appear to have focused almost exclusively on marine resources. In contrast, a highly terrestrial diet is suggested for groups from Nebira in Papua New Guinea and Lake Rotoiti in New Zealand.
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De, roubin Antoine. "Mass measurements of neutron-rich strontium and rubidium isotopes in the A ≈ 100 and development of an electrospray ionization ion source." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0426/document.
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Une extension de la surface de masses atomiques dans la région A ≈ 100 est présentée par l’intermédiaire des mesures de masse des isotopes 100-102Sr et 100-102Rb. Les mesures ont été effectuées avec le spectromètre de masse ISOLTRAP constitué de différents pièges à ions. Les premières mesures directes des masses des 100-102Sr et du 100-102Rb sont rapportées ici. Ces mesures confirment la continuité de la région de déformation nucléaire avec l’augmentation du nombre de neutrons jusqu’à N = 65.De sorte à interpréter la déformation dans la chaine isotopique du strontium et à déterminer si une déformation peut apparaitre pour des isotopes de krypton plus lourds, une comparaison est faite entre les données expérimentales et des résultats de calculs théoriques disponibles dans la littérature. Pour compléter ces comparaisons, des calculs Hartree-Fock-Bogoliubov pour des isotopes pairs et impairs sont aussi présentés, illustrant la compétition entre formes nucléaires dans la région.Le développement d’une source d’ions à ionisation par électro nébuliseur est présenté. Cette source peut produire un large panel de masses isobariques destinées à la calibration. La première mise en service de la source est présentée, incluant les résultats des premiers balayages en masse détectés derrière le spectromètre de masse quadripolaire. Une résolution de quelques unités de masses atomiques a été atteinteAn extension of the atomic mass surface in the region A ≈ 100 is performed via massmeasurements of the 100-102Sr and 100-102Rb isotopes with the ion-trap mass spectrometer ISOLTRAPat CERN-ISOLDE. The first direct mass measurements of 102Sr and 101;102Rb are reported here. Thesemeasurements confirm the continuation of the region of nuclear deformation with the increase of neutronnumber, at least as far as N = 65.In order to interpret the deformation in the strontium isotopic chain and to determine whether an onsetof deformation is present in heavier krypton isotopes, a comparison is made between experimentalvalues and theoretical calculations available in the literature. To complete this comparison, Hartree-Fock-Bogoliubov calculations for even and odd isotopes are also presented, illustrating the competitionof nuclear shapes in the region.The development of an electrospray ionization ion source is presented. This source can delivera large range of isobaric masses for calibration purposes. The early commissioning of the sourceis discussed, including the results from the first mass scans detected behind the quadrupole massspectrometer. A resolution of a few atomic mass units is reached
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Seimbille, François. "Approche expérimentale de la dissolution d'assemblages multi-minéraux loin de l'équilibre thermodynamique : utilisation des isotopes du strontium pour quantifier les rapports de vitesse." Paris, Institut de physique du globe, 2003. http://www.theses.fr/2003GLOB0003.
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Le rapport isotopique du Sr dissous lors d'une interaction entre une solution aqueuse et plusieurs minéraux primaires obéit à chaque instant à une équation de mélange. En milieu naturel on ne peut interpréter que les variations de ce rapport car on connait mal les minéraux sources. Pour contourner cette limitation nous avons réalisé au laboratoire deux séries d'hydrothermalisation entre un granite ou un assemblage biotite-oligoclase et des solutions saturées vis à vis des phases néoformées attendues. L'interprétation des rapports isotopiques montre que l'intensité de l'altération des minéraux primaires diminue avec le temps mais sans changement des contributions relatives aux bilans de masse. En introduisant les vitesses spécifiques et les surfaces actives spécifiques, l'interaction eau-roche est décrite par une seule relation cinétique. L'hydrothermalisation d'un granite est essentiellement piloté par le rapport des surfaces spécifiques actives du couple oligoclase-biotiteDissolved strontium isotope ratio during water-rock interaction represents a mass balance between several mineral end-members and the aqueous solution. In natural systems it is difficult to interpret such a ratio, as mineral end-members cannot be easily defined. A set of experiments, where a granite or a biotite - oligoclase assemblage reacted with solution having a composition close to the saturation with secondary minerals, was performed. Our results showed that the intensity of the mineral alteration decreases as function of time without change in the solution mass balance. Introducing the specific surface and active specific surface concepts a single expression may describe the water-rock interaction kinetics. The granite hydrothermal process is mainly ruled by the ratio of the active specific surface related to oligoclase-biotite pair
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Poszwa, Anne. "Utilisation des isotopes du strontium pour évaluer la dynamique des éléments minéraux dans des écosystèmes forestiers sous climat boréal, tempéré et tropical." Nancy, 2000. http://docnum.univ-lorraine.fr/public/SCD_T_2000_0128_POSZWA.pdf.
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Les dynamiques du strontium (sr) et du calcium (ca) ont été étudiées dans différents écosystèmes forestiers sur sol acide et calcaire, afin d'évaluer dans quelle mesure le sr pouvait être utilisé comme un traceur du ca. Nos résultats ont confirmé l'analogie générale entre sr et ca mais ils montrent un transfert préférentiel du ca par rapport au sr vers les feuilles (conduisant à une accumulation préférentielle de ca à la surface du sol via les chutes de feuilles) et suggèrent sur sol acide un prélèvement racinaire préférentiel de ca par rapport au sr. La dynamique des éléments minéraux a été évaluée dans trois écosystèmes forestiers sous climat tropical, boréal et tempéré à partir de la mesure des flux et variations isotopiques du sr dans les arbres et les sols et à l'aide d'un modèle à compartiments et à flux. En Guyane, nous avons mis en évidence le rôle quasi négligeable joué par les racines profondes des arbres dans l'alimentation minérale de la forêt Tropicale humide. Au nord de la Suède, les différences isotopiques observées dans les organes de pins et épicéas croissant en mélange suggèrent d'une part, un prélèvement et un recyclage biologique du sr beaucoup plus fort par l'épicéa, et d'autre part une altération rhizosphérique plus forte par les racines d'épicéa. Les mesures ont par ailleurs confirmé un prélèvement minéral et hydrique plus profond par le pin. Dans les Vosges, la diminution du rapport 8 7sr/ 8 6sr mesurée dans les cernes d'épicéas au cours du temps a été interprétée comme le résultat d'une acidification à long terme des sols de ce peuplement, éventuellement associée à une remontée des racines. Ces mécanismes paraissent être responsables de l'augmentation du stress hydrique subi par le peuplement.