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Sample records for strontium isotope system

  1. Fractionation of strontium isotopes in cation-exchange chromatography

    SciTech Connect

    Oi, Takao; Ogino, Hideki; Kakihana, Hidetake ); Hosoe, Morikazu )

    1992-04-01

    Strontium isotope fractionation has been observed in cation-exchange chromatography of strontium salts. The heavier isotopes have been found enriched at the front parts of displacement-type chromatograms, which means that the heavier isotopes are preferentially fractionated into the solution phase. The average values of the single-stage separation factor (S) minus one per unit mass difference between isotopes have been 1.0 {times} 10{sup {minus}6} for the strontium chloride system, 2.9 {times} 10{sup {minus}6} for the strontium acetate system, and 3.1 {times} 10{sup {minus}6} for the strontium lactate system at 25C. No evidence of the odd-even anomalous isotope effects has been observed. The isotopic reduced partition function ratios (RPFRs) of the strontium species involved in the present study have been estimated; the RPFRs of the complex species have been found to be larger than that of simple hydrated strontium lactate and strontium acetate systems are larger than that of the strontium chloride system.

  2. High-resolution stratigraphy with strontium isotopes.

    PubMed

    Depaolo, D J; Ingram, B L

    1985-02-22

    The isotopic ratio of strontium-87 to strontium-86 shows no detectable variation in present-day ocean water but changes slowly over millions of years. The strontium contained in carbonate shells of marine organisms records the ratio of strontium-87 to strontium-86 of the oceans at the time that the shells form. Sedimentary rocks composed of accumulated fossil carbonate shells can be dated and correlated with the use of high precision measurements of the ratio of strontium-87 to strontium-86 with a resolution that is similar to that of other techniques used in age correlation. This method may prove valuable for many geological, paleontological, paleooceanographic, and geochemical problems.

  3. Strontium Isotopes and Magma Dynamics

    NASA Astrophysics Data System (ADS)

    Wolff, J. A.; Ellis, B. S.; Ramos, F. C.

    2010-12-01

    Over the past decade, it has become clear that volcanic rocks commonly exhibit internal heterogeneity in radiogenic isotopes. In particular, strontium isotopic disequilibrium between co-exisitng phenocrysts, between phenocrysts and matrix, and isotopic zoning within single crystals has been demonstrated in basalts, andesites, dacites, rhyolites and alkaline magmas; in some cases, the range in 87Sr/86Sr among different components in the same rock may equal or exceed the bulk-rock range seen in the entire formation, volcanic center, or province. High-temperature “Snake River type” rhyolites appear to be an exception. Despite the occurrence of Snake River Plain rhyolites in a region of isotopically highly variable crust and mantle, and significant differences from rhyolite unit to rhyolite unit, internally they are near-homogeneous in 87Sr/86Sr. Little or no zoning is found within feldspar phenocrysts, and feldspars within a single unit are tightly grouped. Some units show minor contrasts between phenocrysts and matrix. High temperature rhyolitic magmas possess a unique combination of temperature and melt viscosity. Although they are typically 200°C hotter than common rhyolites, the effect on visocity is offset by lower water contents (~2 wt%), hence their melt viscosities are in the same range as common, water-rich, cool rhyolites (105 - 106 Pa s). Yet magmatic temperatures are in the same range as basaltic andesites and andesites, consequently cation diffusion rates in feldspar are 2 - 3 orders of magnitude greater than in common rhyolites. We hypothesize that this combination of characteristics promotes Sr isotopic homogeneity: high melt viscosities tend to inhibit crystal transfer and mixing of isotopically distinct components on timescales shorter than those required for diffusive homogenization of Sr between phenocrysts and matrix (100 - 1000 years). This is not the case for most magmas, in which either crystal transfer is rapid (<< 100 years) due to low

  4. Strontium Isotopes and the Reconstruction of the Chaco Regional System: Evaluating Uncertainty with Bayesian Mixing Models

    PubMed Central

    Drake, Brandon Lee; Wills, Wirt H.; Hamilton, Marian I.; Dorshow, Wetherbee

    2014-01-01

    Strontium isotope sourcing has become a common and useful method for assigning sources to archaeological artifacts. In Chaco Canyon, an Ancestral Pueblo regional center in New Mexico, previous studies using these methods have suggested that significant portion of maize and wood originate in the Chuska Mountains region, 75 km to the East. In the present manuscript, these results were tested using both frequentist methods (to determine if geochemical sources can truly be differentiated) and Bayesian methods (to address uncertainty in geochemical source attribution). It was found that Chaco Canyon and the Chuska Mountain region are not easily distinguishable based on radiogenic strontium isotope values. The strontium profiles of many geochemical sources in the region overlap, making it difficult to definitively identify any one particular geochemical source for the canyon's pre-historic maize. Bayesian mixing models support the argument that some spruce and fir wood originated in the San Mateo Mountains, but that this cannot explain all 87Sr/86Sr values in Chaco timber. Overall radiogenic strontium isotope data do not clearly identify a single major geochemical source for maize, ponderosa, and most spruce/fir timber. As such, the degree to which Chaco Canyon relied upon outside support for both food and construction material is still ambiguous. PMID:24854352

  5. Strontium isotopes and the reconstruction of the Chaco regional system: evaluating uncertainty with Bayesian mixing models.

    PubMed

    Drake, Brandon Lee; Wills, Wirt H; Hamilton, Marian I; Dorshow, Wetherbee

    2014-01-01

    Strontium isotope sourcing has become a common and useful method for assigning sources to archaeological artifacts.In Chaco Canyon, an Ancestral Pueblo regional center in New Mexico, previous studiesusing these methods have suggested that significant portion of maize and wood originate in the Chuska Mountains region, 75 km to the West [corrected]. In the present manuscript, these results were tested using both frequentist methods (to determine if geochemical sources can truly be differentiated) and Bayesian methods (to address uncertainty in geochemical source attribution). It was found that Chaco Canyon and the Chuska Mountain region are not easily distinguishable based on radiogenic strontium isotope values. The strontium profiles of many geochemical sources in the region overlap, making it difficult to definitively identify any one particular geochemical source for the canyon's pre-historic maize. Bayesian mixing models support the argument that some spruce and fir wood originated in the San Mateo Mountains, but that this cannot explain all 87Sr/86Sr values in Chaco timber. Overall radiogenic strontium isotope data do not clearly identify a single major geochemical source for maize, ponderosa, and most spruce/fir timber. As such, the degree to which Chaco Canyon relied upon outside support for both food and construction material is still ambiguous.

  6. Salmon origin in California's Sacramento San Joaquin river system as determined by otolith strontium isotopic composition

    NASA Astrophysics Data System (ADS)

    Ingram, B. Lynn; Weber, Peter K.

    1999-09-01

    Geochemical methods for distinguishing salmon of different runs would improve management practices designed to mitigate for declines in salmon populations in California's Sacramento San Joaquin river system. Strontium isotopic measurements show a strong relationship between the 87Sr/86Sr ratio in hatchery water and the 87Sr/86Sr ratio in the otoliths (aragonitic ear bones) of juvenile chinook salmon (Oncorhynchus tshawytscha) raised in those waters. As a result of differences in basin geology from north to south along the western slope of the Sierra Nevada, important salmon spawning rivers within the Sacramento San Joaquin river system have distinct 87Sr/86Sr ratios. Of the 10 rivers in this study, those in the Sacramento River drainage have lower 87Sr/86Sr ratios (0.7039 0.7063) than those in the San Joaquin River basin (0.7068 0.7092), with the exception of the American River, which has the highest 87Sr/86Sr ratios in this study (average 0.7100). The combination of distinct river 87Sr/86Sr ratios and the relationship between water and otolith Sr isotope ratios indicates that this geochemical method can be used to identify the origin (and potentially the migration history) of juvenile, out-migrating salmon in the Sacramento San Joaquin system.

  7. Laser Ablation Molecular Isotopic Spectrometry: Strontium and its isotopes

    NASA Astrophysics Data System (ADS)

    Mao, Xianglei; Bol'shakov, Alexander A.; Choi, Inhee; McKay, Christopher P.; Perry, Dale L.; Sorkhabi, Osman; Russo, Richard E.

    2011-11-01

    The experimental details are reported of Laser Ablation Molecular Isotopic Spectrometry (LAMIS) and its application for performing optical isotopic analysis of solid strontium-containing samples in ambient atmospheric air at normal pressure. The LAMIS detection method is described for strontium isotopes from samples of various chemical and isotopic compositions. The results demonstrate spectrally resolved measurements of the three individual 86Sr, 87Sr, and 88Sr isotopes that are quantified using multivariate calibration of spectra. The observed isotopic shifts are consistent with those calculated theoretically. The measured spectra of diatomic oxide and halides of strontium generated in laser ablation plasmas demonstrate the isotopic resolution and capability of LAMIS. In particular, emission spectra of SrO and SrF molecular radicals provided clean and well resolved spectral signatures for the naturally occurring strontium isotopes. A possibility is discussed of using LAMIS of strontium isotopes for radiogenic age determination.

  8. Origin of fluids and the evolution of the Atlantis II deep hydrothermal system, Red Sea: Strontium isotope study

    SciTech Connect

    Anschutz, P.; Blanc, G.; Stille, P.

    1995-12-31

    Atlantis II is the largest and most mineralized of the deeps along the axis of the Red Sea spreading center. Its basaltic substratum is covered by recent layered metalliferous sediments, which precipitated from an overlying brine pool. The {sup 87}Sr/{sup 86}Sr ratio and the strontium concentration of interstitial waters within these sediments range between 0.70708 and 0.70725 and between 43 and 53 ppm, respectively. They are close to what is found for the present-day deep brine pool (0.707105, 45.10 ppm). The strontium concentration and the {sup 87}Sr/{sup 86}Sr ratio of the Atlantis II Deep brines can be derived from those of the interstitial waters of the surrounding Miocene evaporite by hydrothermal interaction with oceanic basaltic rocks at a maximal water/rock ratio 2-3. This water/rock ratio is similar to that calculated for oceanic hydrothermal systems on sediment-free ridges. Interstitial waters show a linear trend on plot of {sup 87}Sr/{sup 86}Sr vs. 1/Sr. The highest strontium concentration and the most radiogenic interstitial waters correspond to sediment samples enriched in iron and manganese oxide minerals. These waters reflect the diagenetic release of strontium by oxide minerals and initially precipitated at the interface between the brine pool and more radiogenic seawater. The solid fraction of the sediment has {sup 87}sr{sup 86}Sr isotopic compositions intermediate to those of the brines and seawater. The solid fraction of the sediment has {sup 87}Sr/{sup 86}Sr isotopic compositions intermediate to those of the brines and seawater. The most radiogenic strontium values were observed in samples strongly enriched in marine microbiota. The gradual isotopic evolution in the lowest part of the western basin sediments testifies to the gradual influence of the hydrothermal activity in the deep in the beginning of the Atlantis II Deep sedimentary history. 62 refs., 6 figs., 2 tabs.

  9. Origin of fluids and the evolution of the Atlantis II deep hydrothermal system, Red Sea: Strontium isotope study

    NASA Astrophysics Data System (ADS)

    Anschutz, Pierre; Blanc, Gérard; Stille, Peter

    1995-12-01

    Atlantis II is the largest and most mineralized of the deeps along the axis of the Red Sea spreading center. Its basaltic substratum is covered by recent layered metalliferous sediments, which precipitated from an overlying brine pool. The 87Sr /86Sr ratio and the strontium concentration of interstitial waters within these sediments range between 0.70708 and 0.70725 and between 43 and 53 ppm, respectively. They are close to what is found for the present-day deep brine pool (0.707105, 45.10 ppm). The strontium concentration and the 87Sr /86Sr ratio of the Atlantis II Deep brines can be derived from those of the interstitial waters of the surrounding Miocene evaporite by hydrothermal interaction with oceanic basaltic rocks at a maximal water/rock ratio of 2-3. This water/rock ratio is similar to that calculated for oceanic hydrothermal systems on sediment-free ridges. Interstitial waters show a linear trend on a plot of 87Sr /86Sr vs. 1/Sr. The highest strontium concentration and the most radiogenic interstitial waters correspond to sediment samples enriched in iron and manganese oxide minerals. These waters reflect the diagenetic release of strontium by oxide minerals that initially precipitated at the interface between the brine pool and more radiogenic seawater. The solid fraction of the sediment has 87Sr /86Sr isotopic compositions intermediate to those of the brines and seawater. The most radiogenic strontium values were observed in samples strongly enriched in marine microbiota. The gradual isotopic evolution in the lowest part of the western basin sediments testifies to the gradual influence of the hydrothermal activity in the deep in the beginning of the Atlantis II Deep sedimentary history. The strontium isotopic composition of solid samples from younger metalliferous facies is fairly uniform and close to that of the present-day brine. This isotopic homogeneity indicates that the isotopic composition of mineralizing fluids did not change during the time of

  10. Oxygen, deuterium, and strontium isotope characteristics of the Indus River water system

    NASA Astrophysics Data System (ADS)

    Sharma, Anupam; Kumar, Kamlesh; Laskar, Amzad; Singh, Sunil Kumar; Mehta, Pankaj

    2017-05-01

    Understanding the sources and compositional characteristics of waters and sediments in the Indus River system is extremely important as its water availability is one of the primary factors for sustenance of the irrigation activities and the socioeconomic status of a very densely populated region of the world. Here we used stable isotopic compositions (δD and δ18O) and strontium isotopic ratio (87Sr/86Sr) in the Indus River water, its tributaries and its small streams (nallahs) in the Indian territory to understand the regional hydrology, water sources, and catchment processes (evaporation, transpiration, recycling, and mixing). The δ18O values in the Indus River system (IRS) ranges from - 16.9‰ to - 12.5‰ and δD from - 122.8‰ to - 88.5‰. The Indus River and its major tributaries (such as the Zanskar, Nubra and Shyok rivers) are characterized by relatively lower δ18O values, whereas TangTse and other small streams contributing to the Indus are relatively enriched in 18O. The local meteoric water line for the IRS was found to be δD = 7.87 × δ18O + 11.41, which is similar to the Global Meteoric Water Line (GMWL) indicating meteoric origin of the water and insignificant secondary evaporation in the catchment. The Deuterium excess (d-excess) in the IRS varies between 6.5‰ and 14.9‰ with an average of 11.7‰, which is mostly higher than the long-term average for the Indian summer monsoon ( 8‰). The higher d-excess value is because of the contribution of moisture from westerlies; a simple mass balance shows 26% water in the main Indus channel is contributed by the westerlies originated from the Mediterranean Sea. The Sr isotope ratio in IRS varies between 0.70515 and 0.71291; wherein the Indus, and its tributary rivers Shyok and Nubra, are characterized by relatively high Sr isotope ratios (avg. 0.71086-0.71243) compared to the Zanskar and TangTse tributaries (Sr 0.709) because of the variation in silicate rock weathering component and carbonate

  11. PLANETARY-SCALE STRONTIUM ISOTOPIC HETEROGENEITY AND THE AGE OF VOLATILE DEPLETION OF EARLY SOLAR SYSTEM MATERIALS

    SciTech Connect

    Moynier, Frederic; Podosek, Frank A.; Day, James M. D.; Okui, Wataru; Yokoyama, Tetsuya; Bouvier, Audrey; Walker, Richard J. E-mail: fap@levee.wustl.edu E-mail: rjwalker@umd.edu E-mail: tetsuya.yoko@geo.titech.ac.jp

    2012-10-10

    Isotopic anomalies in planetary materials reflect both early solar nebular heterogeneity inherited from presolar stellar sources and processes that generated non-mass-dependent isotopic fractionations. The characterization of isotopic variations in heavy elements among early solar system materials yields important insight into the stellar environment and formation of the solar system, and about initial isotopic ratios relevant to long-term chronological applications. One such heavy element, strontium, is a central element in the geosciences due to wide application of the long-lived {sup 87}Rb-{sup 87}Sr radioactive as a chronometer. We show that the stable isotopes of Sr were heterogeneously distributed at both the mineral scale and the planetary scale in the early solar system, and also that the Sr isotopic heterogeneities correlate with mass-independent oxygen isotope variations, with only CI chondrites plotting outside of this correlation. The correlation implies that most solar system material formed by mixing of at least two isotopically distinct components: a CV-chondrite-like component and an O-chondrite-like component, and possibly a distinct CI-chondrite-like component. The heterogeneous distribution of Sr isotopes may indicate that variations in initial {sup 87}Sr/{sup 86}Sr of early solar system materials reflect isotopic heterogeneity instead of having chronological significance, as interpreted previously. For example, given the differences in {sup 84}Sr/{sup 86}Sr between calcium aluminum inclusions and eucrites ({epsilon}{sup 84}Sr > 2), the difference in age between these materials would be {approx}6 Ma shorter than previously interpreted, placing the Sr chronology in agreement with other long- and short-lived isotope systems, such as U-Pb and Mn-Cr.

  12. Detecting infiltration and impacts of introduced water using strontium isotopes.

    PubMed

    Brinck, Elizabeth L; Frost, Carol D

    2007-01-01

    Water introduced to surface drainages, such as agricultural and roadway runoff, mine drainage, or coalbed natural gas (CBNG)-produced water, potentially can be of environmental concern. In order to mitigate potential environmental effects, it may be important to be able to trace water discharged to the surface as it infiltrates and interacts with near-surface aquifers. We have chosen to study water withdrawn during CBNG production for isotope tracing in the hyporheic zone because it poses a variety of economic, environmental, and policy issues in the Rocky Mountain states. Ground water quality must be protected as CBNG water is added to semiarid ecosystems. Strontium (Sr) isotopes are effective fingerprints of the aquifer from which water originates. In this study, CBNG water was found to have a higher (87)Sr/(86)Sr ratio than the local alluvial aquifer water. This measurable difference allows the strontium isotope ratio and concentration to be used as tracers of CBNG water following its discharge to the surface. The dissolution and mobilization of salts from soil are an important contributor to ground water quality degradation. In the Powder River basin of Wyoming, the soils are calcium carbonate-buffered systems. The chemical similarity of strontium to calcium allows it to substitute into calcium minerals and enabled us to use strontium isotopes to identify calcium salts mobilized from the soil. Strontium isotopes are an effective monitor of the source of ions and the volume and direction of introduced water flow in the hyporheic zone.

  13. Detecting infiltration and impacts of introduced water using strontium isotopes

    SciTech Connect

    Brinck, E.L.; Frost, C.D.

    2007-09-15

    Water introduced to surface drainages, such as agricultural and roadway runoff, mine drainage, or coalbed natural gas (CBNG)-produced water, potentially can be of environmental concern. In order to mitigate potential environmental effects, it may be important to be able to trace water discharged to the surface as it infiltrates and interacts with near-surface aquifers. We have chosen to study water withdrawn during CBNG production for isotope tracing in the hyporheic zone because it poses a variety of economic, environmental, and policy issues in the Rocky Mountain states. Ground water quality must be protected as CBNG water is added to semiarid ecosystems. Strontium (Sr) isotopes are effective fingerprints of the aquifer from which water originates. In this study, CBNG water was found to have a higher Sr-87/Sr-86 ratio than the local alluvial aquifer water. This measurable difference allows the strontium isotope ratio and concentration to be used as tracers of CBNG water following its discharge to the surface. The dissolution and mobilization of salts from soil are an important contributor to ground water quality degradation. In the Powder River basin of Wyoming, the soils are calcium carbonate-buffered systems. The chemical similarity of strontium to calcium allows it to substitute into calcium minerals and enabled us to use strontium isotopes to identify calcium salts mobilized from the soil. Strontium isotopes are an effective monitor of the source of ions and the volume and direction of introduced water flow in the hyporheic zone.

  14. Lithostratigraphy, petrography, biostratigraphy, and strontium-isotope stratigraphy of the surficial aquifer system of western Collier County, Florida

    USGS Publications Warehouse

    Edwards, L.E.; Weedman, S.D.; Simmons, R.; Scott, T.M.; Brewster-Wingard, G. L.; Ishman, S.E.; Carlin, N.M.

    1998-01-01

    overlie the Pliocene limestones in two cores in the southern part of the study area. Artificial fill occurs at the top of most of the cores. The hydrologic confining units penetrated by these cores are different in different parts of the study area. To the west, a hard tightly cemented dolostone forms the first major confining unit below the water table. In the eastern part of the study area, confinement is more difficult to determine. A tightly cemented sandstone, much younger than the dolostones to the west and probably not laterally connected to them, forms a slight confining unit in one core. Thick zones of poorly sorted muddy unconsolidated sands form a slight confining unit in other cores; these probably are not correlative to either the sandstone or the dolostones to the west. The age and sedimentologic observations suggest a complex compartmentalization of the surficial aquifer system in southwestern Florida. The calibrations of dinocyst and molluscan occurrences with strontium-isotope stratigraphy allows us to expand and document the reported ranges of many taxa. This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  15. High temperature strontium stable isotope behaviour in the early solar system and planetary bodies

    NASA Astrophysics Data System (ADS)

    Charlier, B. L. A.; Nowell, G. M.; Parkinson, I. J.; Kelley, S. P.; Pearson, D. G.; Burton, K. W.

    2012-05-01

    This study presents comprehensive strontium stable isotope (88Sr/86Sr) data, measured by multiple-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS), for a suite of carbonaceous chondrites, differentiated meteorites, lunar, martian and terrestrial samples. Carbonaceous chondrites comprise a mixture of refractory inclusions and chondrules that have light δ88Sr values between - 0.35 to + 0.05‰ and matrix material that possesses a heavy δ88Sr composition of 0.65‰, confirming the results of earlier studies. Consequently, bulk carbonaceous chondrites are relatively heterogeneous in composition ranging from + 0.12 to + 0.35‰, most likely reflecting clast-matrix variability. The light δ88Sr compositions of the refractory inclusions are consistent with mass dependent fractionation of other refractory elements (Ca and Eu) and are most likely produced by non-equilibrium fractionation (undercooling in the nebula gas) during condensation of hibonite from the solar nebula (Simon and DePaolo, 2010. Stable calcium isotopic composition of meteorites and rocky planets. Earth Planet. Sci. Lett. 289, 457-466). Carbonaceous chondrites, angrites and martian meteorites have indistinguishable compositions at the level of analytical uncertainty of this study. However, statistical analysis indicates that melts derived from the Earth's mantle have heavier δ88Sr values than bulk carbonaceous chondrites and martian meteorites, but compositions indistinguishable from eucrites (δ88Sr = + 0.26 ± 0.12‰). Moreover, terrestrial basalts and andesites have restricted δ88Sr values (+ 0.30 ± 0.07‰), suggesting that mantle melting delivers rather homogenous melts to the Earth's surface with respect to δ88Sr. In contrast, glasses from evolved terrestrial rocks and lunar basalts extend to very light δ88Sr values ~-0.20‰. The Sr stable isotope composition covaries with europium anomaly (Eu/Eu*), as an index of plagioclase fractionation, and δ88Sr can be successfully

  16. Strontium and oxygen isotopic profiles through 3 km of hydrothermally altered oceanic crust in the Reykjanes Geothermal System, Iceland

    NASA Astrophysics Data System (ADS)

    Marks, N. E.; Zierenberg, R. A.; Schiffman, P.

    2010-12-01

    The Iceland Deep Drilling Program well of opportunity RN-17 was drilled 3 km into a section of hydrothermally altered basaltic crust in the Reykjanes geothermal system in Iceland. The system is located on the landward extension of the Mid-Atlantic Ridge, and the circulating hydrothermal fluid is modified seawater, making Reykjanes a useful analogue for mid-oceanic ridge hydrothermal systems. Whole rock oxygen isotope ratios range from -0.13 to 3.61‰, which are significantly depleted relative to fresh MORB (5.8±0.2‰). If oxygen isotope exchange between fluid and rock proceeded under equilibrium in a closed system, the bulk of the exchange must have occurred in the presence of a meteoric- as opposed to seawater-derived fluid. The concentrations of Sr in the altered basalt range from well below to well above concentrations in fresh rock, and appear to be strongly correlated with the dominant alteration mineralogy, although there is no correlation with 87Sr/86Sr isotopic ratios. Whole rock Sr isotopic ratios ranged from 0.70329 in the least altered crystalline basalt, to 0.70609 in the most altered hyaloclastite samples; there is no correlation with depth. Sr isotopic variation in epidote grains measured by laser ablation MC-ICP-MS ranged from 0.70353 to 0.70731. Three depth intervals have distinctive isotopic signatures, at 1000 m, 1350 m, and 2000 m depth, where 87Sr/86Sr ratios are elevated (mean value >0.7050) relative to background levels (mean altered basalt value ~0.7042). These areas are proximal to feed zones, and the 1350 m interval directly overlies the transition from dominantly extrusive to intrusive lithologies. Strontium and oxygen isotope data indicate that the greenschist-altered basalts were in equilibrium with modified hydrothermal fluids at a relatively high mean water/rock mass ratios (generally in the range 1-3), and require the presence of both meteoric- and seawater-derived recharge fluids at various stages in the hydrothermal history.

  17. Strontium concentrations and isotope ratios in a forest-river system in the South Qinling Mts., China.

    PubMed

    Bu, Hongmei; Song, Xianfang; Zhang, Quanfa; Burford, Michele A

    2016-04-15

    The concentrations of dissolved strontium (Sr) and isotope ratios ((87)Sr/(86)Sr) in rainwater, river water, and water from forest soil are measured to investigate the contributions of these sources to a river during base flow conditions in the relatively pristine South Qinling Mountains, China. Dissolved Sr concentrations and (87)Sr/(86)Sr ratios vary significantly between different water types (p < 0.01) suggesting that it is suitable for differentiating sources. Dissolved Sr is also positively correlated with most ions and a range of physicochemical parameters (p < 0.01 and p < 0.05 respectively) in water samples including Ca(2+), Mg(2+), EC, and TDS (p < 0.001) indicating their similarities in the drivers of biogeochemical processes and common origins. The correlations between Sr isotopes and Ca/Na, Ca/K, and 1000/Sr ratios suggest that three end-members of atmospheric inputs, carbonate and silicate weathering control the Sr water chemistry in the river water. Using the three-source mixing model, atmospheric inputs, carbonate, and silicate weathering contribute 74%, 20%, and 6% respectively to the dissolved Sr in the river water. This research has provided new insights into the contribution of sources of Sr to a river system in a mountainous catchment.

  18. Controls over the strontium isotope composition of river water

    SciTech Connect

    Palmer, M.R. ); Edmond, J.M. )

    1992-05-01

    Strontium concentrations and isotope ratios have been measured in river and ground waters from the Granges, Orinoco, and Amazon river basins. When compared with major element concentrations, the data set has allowed a detailed examination of the controls over the strontium isotope systematics of riverine input to the oceans in the following environments: (1) typical drainage basins containing limestones, evaporites, shales, and alumino-silicate metamorphic and igneous rocks; (2) shield terrains containing no chemical or biogenic sediments; and (3) the flood plains that constitute the largest areas of many large rivers. The strontium concentration and isotope compositions of river waters are largely defined by mixing of strontium derived from limestones and evaporites with strontium derived from silicate rocks. The strontium isotope composition of the limestone end member generally lies within the Phanerozoic seawater range, which buffers the [sup 87]Sr/[sup 86]Sr ratios of major rivers. A major exception is provided by the rivers draining the Himalayas, where widescale regional metamorphism appears to have led to an enrichment in limestones of radiogenic strontium derived from coexisting silicate rocks. The strontium isotope systematics of rivers draining shield areas are controlled by the intense, transport-limited, nature of the weathering reactions, and thereby limits variations in the strontium flux from these terrains. Flood plains are only a minor source of dissolved strontium to river waters, and precipitation of soil salts in some flood plains can reduce the riverine flux of dissolved strontium to the oceans.

  19. On strontium isotopic anomalies and odd-A p-process abundances. [in solar system

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1978-01-01

    Several aspects of the nucleosynthesis of Sr isotopes are considered in an attempt to shed light on the problem of the Sr isotopic anomalies discovered in an inclusion of the Allende meteorite. Decomposition of the Sr isotopes into average r-, s-, and p-process nucleosynthetic classes is performed. It is suggested that the Allende inclusion most likely has an excess of s-process Sr and that the initial Sr-87/Sr-86 isotopic ratio is probably slightly more primitive than basaltic achondrites. The results also show that Sn-115 is mostly due to the r-process and that odd-A yields are very small. It is concluded that if the Sr anomaly in the inclusion is an average s enhancement, it argues somewhat in favor of a model of gas/dust fractionation of s and r isotopes during accumulation of the inclusion parent in the protosolar cloud.

  20. Controls over the strontium isotope composition of river water

    NASA Astrophysics Data System (ADS)

    Palmer, M. R.; Edmond, J. M.

    1992-05-01

    Strontium concentrations and isotope ratios have been measured in river and ground waters from the Ganges, Orinoco, and Amazon river basins. When compared with major element concentrations, the data set has allowed a detailed examination of the controls over the strontium isotope systematics of riverine input to the oceans in the following environments: (1) "typical" drainage basins containing limestones, evaporites, shales, and alumino-silicate metamorphic and igneous rocks; (2) shield terrains containing no chemical or biogenic sediments; and (3) the floodplains that constitute the largest areas of many large rivers. The strontium concentration and isotope composition of river waters are largely defined by mixing of strontium derived from limestones and evaporites with strontium derived from silicate rocks. The strontium isotope composition of the limestone endmember generally lies within the Phanerozoic seawater range, which buffers the 87Sr /86Sr ratios of major rivers. A major exception is provided by the rivers draining the Himalayas, where widescale regional metamorphism appears to have led to an enrichment in limestones of radiogenic strontium derived from coexisting silicate rocks. The strontium isotope systematics of rivers draining shield areas are controlled by the intense, transportlimited, nature of the weathering reactions, and thereby limits variations in the strontium flux from these terrains. Floodplains are only a minor source of dissolved strontium to river waters, and precipitation of soil salts in some floodplains can reduce the riverine flux of dissolved strontium to the oceans. The most effective mechanisms for altering the isotope ratio and flux of riverine strontium to the oceans are increased glaciation and large-scale regional metamorphism of the type produced during continental collision. Both mechanisms provide a means for increasing the 87Sr /86Sr ratio of the global riverine flux.

  1. Strontium stable isotope behaviour accompanying basalt weathering

    NASA Astrophysics Data System (ADS)

    Burton, K. W.; Parkinson, I. J.; Gíslason, S. G. R.

    2016-12-01

    The strontium (Sr) stable isotope composition of rivers is strongly controlled by the balance of carbonate to silicate weathering (Krabbenhöft et al. 2010; Pearce et al. 2015). However, rivers draining silicate catchments possess distinctly heavier Sr stable isotope values than their bedrock compositions, pointing to significant fractionation during weathering. Some have argued for preferential release of heavy Sr from primary phases during chemical weathering, others for the formation of secondary weathering minerals that incorporate light isotopes. This study presents high-precision double-spike Sr stable isotope data for soils, rivers, ground waters and estuarine waters from Iceland, reflecting both natural weathering and societal impacts on those environments. The bedrock in Iceland is dominantly basaltic, d88/86Sr ≈ +0.27, extending to lighter values for rhyolites. Geothermal waters range from basaltic Sr stable compositions to those akin to seawater. Soil pore waters reflect a balance of input from primary mineral weathering, precipitation and litter recycling and removal into secondary phases and vegetation. Rivers and ground waters possess a wide range of d88/86Sr compositions from +0.101 to +0.858. Elemental and isotope data indicate that this fractionation primarily results from the formation or dissolution of secondary zeolite (d88/86Sr ≈ +0.10), but also carbonate (d88/86Sr ≈ +0.22) and sometimes anhydrite (d88/86Sr ≈ -0.73), driving the residual waters to heavier or lighter values, respectively. Estuarine waters largely reflect mixing with seawater, but are also be affected by adsorption onto particulates, again driving water to heavy values. Overall, these data indicate that the stability and nature of secondary weathering phases, exerts a strong control on the Sr stable isotope composition of silicate rivers. [1] Krabbenhöft et al. (2010) Geochim. Cosmochim. Acta 74, 4097-4109. [2] Pearce et al. (2015) Geochim. Cosmochim. Acta 157, 125-146.

  2. Discovery of rubidium, strontium, molybdenum, and rhodium isotopes

    SciTech Connect

    Parker, A.M.; Thoennessen, M.

    2012-07-15

    Currently, 31 rubidium, 35 strontium, 35 molybdenum, and 38 rhodium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  3. Strontium isotopic stratigraphy utilizing authigenic dolomites in hemipelagic sediments

    SciTech Connect

    Baker, P.A. ); Kastner, M. ); Elderfield, H. )

    1990-05-01

    Authigenic dolomites commonly occur in organic-rich, continental margin marine sediments. These dolomites play a key role in the age dating of stratigraphic sections. The dolomites often are the only lithology amenable to paleomagnetic stratigraphy; they preserve siliceous microfossils against diagenetic; recrystallization, and provide useful strontium isotopic stratigraphic ages. Several potential sources of error frequently are unique to the use of authigenic dolomites in the strontium isotope methods. (1) The dolomites occur as cements of the host lithology, hence, they are not a pure phase. Potentially important contaminants during analysis include gypsum clay minerals, feldspars, and iron and manganese oxides. Strontium may occur as a structural substituent ion in these minerals or as a surface-adsorbed ion. Various leaching techniques have been tested to isolate dolomitic strontium. Purer dolomites and strontium-enriched dolomites often can be selected to ease these problems. (2) The dolomites form after the deposition of the host sediment, therefore, they record the diagenetic age not the depositional age. The stable isotopic composition of the dolomites can aid in selection of early formed samples. (3) The dolomites record pore-water strontium isotope compositions, not seawater isotopic compositions. This problem is also minimized by choosing dolomites formed near the sediment-water interface. (4) The dolomites formed near the sediment-water interface originated as rotodolomites and undergo subsequent burial diagenesis, creating a potential for later strontium isotope exchange. This problem is minimized by selecting fresh samples from the interior of nearly impermeable beds and nodules. Results from the Miocene Monterey Formation of California and from the Eocene through Pliocene Pisco basin of Peru show that authigenic dolomites can provide useful strontium isotopic age estimates.

  4. Human impacts on karst groundwater contamination deduced by coupled nitrogen with strontium isotopes in the Nandong Underground River System in Yunan, China.

    PubMed

    Jiang, Yongjun; Wu, Yuexia; Yuan, Daoxian

    2009-10-15

    With the rapid increase in population and economy, groundwater quality has degraded in the Nandong Underground River System (NURS), a typical karst underground river developed in carbonate rocks (limestone and dolomite), which is located in an agriculture-dominated area in the southeast Yunnan Province, China. Determining sources of contamination in the groundwater is an important first step toward us improving its quality by emission control. It is with this aim that we reviewed here the benefit of using a coupled isotopic approach (delta15N and 87Sr/86Sr) to trace the origin of contamination in groundwater. Thirty-six representative groundwater samples, which were collected at different aquifers and land use types, showed significant disparities for major element concentrations and Sr and N isotopic composition in the NURS. Nitrate, along with Cl- and SO4(2-) and some Na+ and K+, pollution of groundwater is a significant problem in the NURS. The joint use of nitrogen and strontium isotope systematics in each context deciphered the origin of contamination in groundwater in the NURS as agricultural fertilizers and sewage effluents. Therefore, an increase in knowledge of groundwater geochemistry by means of hydrochemical and isotopic data will be helpful for understanding water-rock interactions and the influence of human activities on the hydrogeochemical environment of karst groundwater and provide a scientific basis for protection and rational utilization of groundwater resources in karst regions.

  5. Specific activity and isotope abundances of strontium in purified strontium-82

    SciTech Connect

    Fitzsimmons, J. M.; Medvedev, D. G.; Mausner, L. F.

    2015-11-12

    A linear accelerator was used to irradiate a rubidium chloride target with protons to produce strontium-82 (Sr-82), and the Sr-82 was purified by ion exchange chromatography. The amount of strontium associated with the purified Sr-82 was determined by either: ICP-OES or method B which consisted of a summation of strontium quantified by gamma spectroscopy and ICP-MS. The summation method agreed within 10% to the ICP-OES for the total mass of strontium and the subsequent specific activities were determined to be 0.25–0.52 TBq mg-1. Method B was used to determine the isotope abundances by weight% of the purified Sr-82, and the abundances were: Sr-82 (10–20.7%), Sr-83 (0–0.05%), Sr-84 (35–48.5%), Sr-85 (16–25%), Sr-86 (12.5–23%), Sr-87 (0%), and Sr-88 (0–10%). The purified strontium contained mass amounts of Sr-82, Sr-84, Sr-85, Sr-86, and Sr-88 in abundances not associated with natural abundance, and 90% of the strontium was produced by the proton irradiation. A comparison of ICP-OES and method B for the analysis of Sr-82 indicated analysis by ICP-OES would be easier to determine total mass of strontium and comply with regulatory requirements. An ICP-OES analytical method for Sr-82 analysis was established and validated according to regulatory guidelines.

  6. Strontium isotopes as an indicator for groundwater salinity sources in the Kirkuk region, Iraq.

    PubMed

    Sahib, Layth Y; Marandi, Andres; Schüth, Christoph

    2016-08-15

    The Kirkuk region in northern Iraq hosts some of the largest oil fields in the Middle East. Several anticline structures enabled vertical migration and entrapment of the oil. Frequently, complex fracture systems and faults cut across the Eocene and middle Oligocene reservoirs and the cap rock, the Fatha Formation of Miocene age. Seepage of crude oil and oil field brines are therefore a common observation in the anticline axes and contamination of shallow groundwater resources is a major concern. In this study, 65 water samples were collected in the Kirkuk region to analyze and distinguish mixing processes between shallow groundwater resources, uprising oil field brines, and dissolution of gypsum and halite from the Fatha Formation. Hydrochemical analyses of the water samples included general hydrochemistry, stable water isotopes, as well as strontium concentrations and for 22 of the samples strontium isotopes ((87)Sr/(86)Sr). Strontium concentrations increased close to the anticline axes with highest concentrations in the oil field brines (300mg/l). Strontium isotopes proved to be a valuable tool to distinguish mixing processes as isotope signatures of the oil field brines and of waters from the Fatha Formation are significantly different. It could be shown, that mixing of shallow groundwater with oil field brines is occurring close to the major fault zones in the anticlines but high concentrations of strontium in the water samples are mainly due to dissolution from the Fatha Formation.

  7. Strontium isotope geochemistry of soil and playa deposits near Yucca Mountain, Nevada

    SciTech Connect

    Marshall, B.D.; Mahan, S.A.

    1994-12-31

    The isotopic composition of strontium contained in the carbonate fractions of soils provides an excellent tracer which can be used to test models for their origin. This paper reports data on surface coatings and cements, eolian sediments, playas and alluvial fan soils which help to constrain a model for formation of the extensive calcretes and fault infilling in the Yucca Mountain region. The playas contain carbonate with a wide range of strontium compositions; further work will be required to fully understand their possible contributions to the pedogenic carbonate system. Soils from an alluvial fan to the west of Yucca Mountain show that only small amounts of strontium are derived from weathering of silicate detritus. However, calcretes from a fan draining a carbonate terrane have strontium compositions dominated locally by the limestone strontium component. Although much evidence points to an eolian source for at least some of the strontium in the pedogenic carbonates near Yucca Mountain, an additional component or past variation of strontium composition in the eolian source is required to model the pedogenic carbonate system.

  8. Strontium isotope study, Pine Barrens, Long Island, NY

    SciTech Connect

    Xin, Geng; Hanson, G.N. . Dept. of Earth and Space Sciences)

    1993-03-01

    Twenty-four samples representing precipitation, through-fall, soil water, ground water, vegetation and soil were analyzed for strontium concentration and the [sup 87]Sr/[sup 86]Sr ratio. The Pine Barrens, which consists of forests and dense vegetation, covers approximately 300 square miles of the coastal plain of Long Island, New York. This study estimates the relative importance of atmospheric and weathering inputs of Sr to vegetation in this ecosystem. The values of the [sup 87]Sr/[sup 86]Sr ratios and Sr concentration in the Pine Barrens are shown in the attached figure. Precipitation has Sr isotopic ratios that are close to that of sea water (0.7092). The Sr in through-fall is dominated by the Sr from the canopy foliage. The [sup 87]Sr/[sup 86]Sr ratios of soil water and ground water increase with depth. The Sr isotopic ratio for a composite sample of pine (0.71181) is a mixture of atmosphere Sr and soil or ground waters. The Sr isotopic ratios and concentrations in pine suggest that plants are a major reservoir of Sr in the system.

  9. Strontium isotope ratios and the origin of anorthosites

    SciTech Connect

    Vinogradov, V.I.

    1986-01-01

    Anorthosites are rocks consisting almost completely of calcic plagioclase, usually from andesine to labradorite. They are not widespread, and until recently were of no economic interest. However, with the advance of the new global tectonics, which has excited considerable interest in the structure and composition of upper-mantle rocks, interest in the anorthosites has grown. This has particularly been the case since the discovery of anorthosites on the moon, where they appear to be more widespread than on the earth. Data have recently been obtained on the strontium isotope compositions of anorthosite intrusions in the Dzhugdzhur-Stanovoy zone and in the rocks surrounding them, which have revealed some unexpected features. The paper describes the geological features of anorthosites, initial concepts on strontium isotope geochemistry, strontium isotope compositions of this region, and discusses some genetic consequences from the isotope data. Although the data of this study are insufficient to determine the origin of anorthosites, the data indicate several points which should be considered in following studies. 11 references, 1 figure.

  10. Isotopic composition of strontium in sea water throughout Phanerozoic time

    USGS Publications Warehouse

    Peterman, Z.E.; Hedge, C.E.; Tourtelot, H.A.

    1970-01-01

    Isotopic analyses of strontium in primary fossil carbonate reveal significant variations in Sr87 Sr86 of sea water during the Phanerozoic. The strontium isotopic composition may have been uniform from the Ordovician through the Mississippian, with an average Sr87 Sr86 of 0.7078. A subsequent decrease in this value into the Mesozoic is interrupted by two provisionally documented positive pulses in Sr87 Sr86-one in the Early Pennsylvanian and one in the Early Triassic. The lowest observed value (0.7068) occurred in Late Jurassic time, and this was followed by a gradual increase to 0.7075 in the Late Cretaceous and a more rapid increase through the Tertiary to 0.7090 for modern sea water. These variations are thought to be the result of a complex interplay of periods of intense volcanism and epeirogenic movements of the continents on a worldwide scale. ?? 1970.

  11. Equilibrium Strontium Isotope Fractionation in Minerals and Solution

    NASA Astrophysics Data System (ADS)

    Schauble, E. A.; Griffith, E. M.

    2011-12-01

    Recent interest in stable strontium isotope fractionation highlights our lack of understanding of the processes separating the isotopes of heavy elements in nature. Here we present thermodynamic calculations of equilibrium strontium isotope (88Sr/86Sr) fractionation in minerals and aqueous solution (by analogy to crystalline strontium hydrates). Strontium is among the ten most abundant dissolved ions seawater, and is unique in this group because it encompasses an extensively studied, long-lived radiogenic tracer (87Sr/86Sr) as well as three stable isotopes. Strontium is also widely distributed as a trace element in sedimentary minerals (especially carbonates and sulfates) and more broadly as a substituent for the major elements calcium, sodium and/or potassium in high-temperature igneous and metamorphic assemblages. However, we are aware of only a few theoretical or experimental studies of fractionation of strontium isotopes in crystals or solution (1). An important goal of our work is to provide a baseline for determining whether equilibrium isotope partitioning is important for generating observed signatures, which can be particularly difficult to establish experimentally in solid materials at ambient temperatures. Mass dependent fractionations are estimated for stoichiometric strontium-bearing crystals, including strontianite (SrCO3), celestine (SrSO4), strontia (SrO), and strontiofluorite (SrF2), as well as crystals with hydrated Sr2+-ions (e.g., SrCl2.6H2O, which contains a [Sr(H2O)9]2+ substructure) and strontium-substituted barite (Sr:BaSO4). Calculations are based on density functional perturbation theory models of the vibrational (phonon) densities of states of 86Sr- and 88Sr-substituted crystals. Most of the models of celestine indicate instability in the known orthorhombic structure - possibly because of shortcomings in pseudopotentials or density functionals. The models predict that fractionations between crystals tend to be small; strontia

  12. Isolation of strontium pools and isotope ratios in modern human hair.

    PubMed

    Tipple, Brett J; Chau, Thuan; Chesson, Lesley A; Fernandez, Diego P; Ehleringer, James R

    2013-10-10

    The elements of human hair record specific information about an individual's health, diet, and surrounding environment. Strontium isotope ratios of human hair have attracted interest as they potentially record an individual's environment. Yet, separating the external environmental signals from the internal dietary indicators has remained a challenge. Here, we examined the effects of five different hair-cleaning methodologies to determine the extent that internal and external strontium signals can be isolated from human hair. In the first study of its kind, we employed an in-line strontium purification methodology and a multi-collector inductively coupled plasma mass spectrometer to obtain high-precision strontium isotope ratio of human hair and of leachates of the different washing treatments. We found that the different applications of an individual treatment removed a consistent amount of strontium from hair and that replicate analyses showed each treatment altered the strontium isotope ratios of hair consistently. A mass-balance approach was applied to demonstrate that strontium was quantitatively removed and was accounted for in either the treated hair or the leachate. We observed that strontium isotope ratio varied as a function of treatment aggressiveness so as to suggest that there was a fine-scale structuring of strontium within hair (transverse cross-sectional variations); these variations existed as differences in strontium concentrations and isotope ratios. As a result, the Sr isotope ratio of hair and hair leachates treated with the most aggressive cleaning methods reflected the isotope ratios of the interior and total exterior strontium signatures, respectively. The results of this study indicate that external environmental strontium signals can be distinguished from the internal signals and therefore permit the application of strontium isotope ratios of modern human hair for geospatial applications.

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

    USGS Publications Warehouse

    Hedman, Kristin M.; Curry, B. Brandon; Johnson, Thomas M.; Fullagar, Paul D.; Emerson, Thomas E.

    2009-01-01

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

  14. Strontium-isotope stratigraphy of Enewetak Atoll

    USGS Publications Warehouse

    Ludwig, K. R.; Halley, Robert B.; Simmons, Kathleen R.; Peterman, Zell E.

    1988-01-01

    87Sr/86Sr ratios determined for samples from a 350 m core of Neogene lagoonal, shallow-water limestones from Enewetak Atoll display a remarkably informative trend. Like the recently published data for Deep Sea Drilling Project (DSDP) carbonates, 87Sr/86Sr at Enewetak increases monotonically but not smoothly from the early Miocene to the Pleistocene. The data show intervals of little or no change in 87Sr/86Sr, punctuated by sharp transitions to lower values toward greater core depths. The sharp transitions correlate with observed solution disconformities caused by periods of subaerial erosion, whereas the intervals of little or no change in 87Sr/86Sr correspond to intervals of rapid accumulation of shallow-water carbonate sediments. When converted to numerical ages using the published DSDP 590B trend, the best-resolved time breaks are at 282 m (12.3 to 18.2 Ma missing) and 121.6 m (3.0 to 5.3 Ma missing) below the lagoon floor. At Enewetak, Sr isotopes offer a stratigraphic resolution for these shallow-marine Neogene carbonates comparable to that of nannofossil zonation in deep-sea carbonates (0.3-3 m.y.). In addition, the correlation of times of Sr-isotope breaks at Enewetak with times of rapid Sr-isotope change in the DSDP 590B samples confirms the importance off sea-level changes in the evolution of global-marine Sr isotopes and shows that the Sr-isotope response to sea-level falls is rapid.

  15. Strontium-isotope stratigraphy of Enewetak Atoll

    NASA Astrophysics Data System (ADS)

    Ludwig, K. R.; Halley, R. B.; Simmons, K. R.; Peterman, Z. E.

    1988-02-01

    87Sr/86Sr ratios determined for samples from a 350 m core of Neogene lagoonal, shallow-water limestones from Enewetak Atoll display a remarkably informative trend. Like the recently published data for Deep Sea Drilling Project (DSDP) carbonates, 87Sr/86Sr at Enewetak increases monotonically but not smoothly from the early Miocene to the Pleistocene. The data show intervals of little or no change in 87Sr/86Sr, punctuated by sharp transitions to lower values toward greater core depths. The sharp transitions correlate with observed solution disconformities caused by periods of subaerial erosion, whereas the intervals of little or no change in 87Sr/86Sr correspond to intervals of rapid accumulation of shallow-water carbonate sediments. When converted to numerical ages using the published DSDP 590B trend, the best-resolved time breaks are at 282 m (12.3 to 18.2 Ma missing) and 121.6 m (3.0 to 5.3 Ma missing) below the lagoon floor. At Enewetak, Sr isotopes offer a stratigraphic resolution for these shallow-marine Neogene carbonates comparable to that of nannofossil zonation in deep-sea carbonates (0.3-3 m.y.). In addition, the correlation of times of Sr-isotope breaks at Enewetak with times of rapid Sr-isotope change in the DSDP 590B samples confirms the importance off sea-level changes in the evolution of global-marine Sr isotopes and shows that the Sr-isotope response to sea-level falls is rapid.

  16. Seawater strontium isotopes at the Cretaceous-Tertiary boundary

    NASA Technical Reports Server (NTRS)

    Macdougall, J. D.; Martin, E.

    1988-01-01

    Anomalously high values of Seawater Sr-87/Sr-86 near the Cretaceous-Tertiary (K-T) boundary have been reported. However, few of the data from the literature are from a single continuous section, and perhaps the most complete study of the boundary region, from a shallow marine limestone sequence in Alabama, showed elevated Sr-87/Sr-86 but no pronounced spike. Thus, in order to investigate the cause of the change in strontium isotopic composition, it is important to determine the exact nature and magnitude of the increase by studying in detail continuous sections through the boundary. If there is indeed a Sr isotope spike at the K-T boundary, it requires the addition of a large amount of radiogenic Sr to the oceans over a short time period, a phenomenon that may be linked to other large-scale environmental disturbances which occurred at that time. In order to address this question, a high-resolution strontium isotope study of foraminifera from three Deep Sea Drilling Project (DSDP) cores which recovered the K-T boundary section: Site 356 in the South Atlantic, Site 384 in the North Atlantic and Site 577 from the Shatsky Rise in the Pacific was initiated. The isotope measurements are being made on either single or small numbers of forams carefully picked and identified and in most cases examined by SEM before analysis. Because this work is not yet complete, conclusions drawn here must be viewed as tentative. They are briefly discussed.

  17. Strontium

    USGS Publications Warehouse

    Ober, J.A.

    1995-01-01

    Part of the 1994 Industrial Minerals Review. The production, consumption, and applications of strontium are reviewed. Consumption for the year is estimated to have been about 35 kt for strontium contained in celestite, strontium carbonate, and strontium nitrate. Exports of strontium totaled only about 1.1 kt for the year. U.S. strontium imports and consumption increased about 30 percent in 1994 due to increased domestic production of color television picture tube glass. The average customs value of celestite coming into the U.S. was about $75/t, strontium carbonate was valued at $661/t, and strontium nitrate was valued at about $1,069/t.

  18. Nucleosynthetic strontium isotope anomalies in carbonaceous chondrites

    NASA Astrophysics Data System (ADS)

    Yokoyama, Tetsuya; Fukami, Yusuke; Okui, Wataru; Ito, Nobuaki; Yamazaki, Hiroshi

    2015-04-01

    Precise Sr isotopic compositions in samples from sequential acid leaching experiments have been determined for three carbonaceous chondrites, Allende, Murchison, and Tagish Lake, together with those in the bulk aliquots of these meteorites. The chondritic acid leachates and residues were characterized by Sr isotope anomalies with variable μ84Sr values (106 relative deviation from a standard material) ranging from +120 to - 4700 ppm, documenting multiple nucleosynthetic sources within a single meteorite. In addition, the μ84Sr patterns across leaching samples for individual chondrites differed from one another. The highest μ84Sr values were observed for leaching Step 3 (HCl+H2O, 75 °C) for Allende and Murchison likely because of the incorporation of calcium and aluminum-rich inclusions (CAIs). In contrast, extremely low μ84Sr values were observed in the later fractions (Steps 6 and 7) for Murchison and Tagish Lake, suggesting the existence of s-process-enriched presolar SiC grains derived from AGB stars. A μ84Sr-ɛ54Cr diagram was prepared with the CAIs and bulk aliquots of carbonaceous chondrites and other meteorites (noncarbonaceous) that were plotted separately; however, they still formed a global positive correlation. CAIs presented the highest μ84Sr and ɛ54Cr values, whereas carbonaceous chondrites and noncarbonaceous meteorites had intermediate and the lowest μ84Sr and ɛ54Cr values, respectively. The positive trend was interpreted as resulting from global thermal processing in which sublimation of high μ84Sr and ɛ54Cr carriers generated the excess μ84Sr and ɛ54Cr signatures in CAIs, while noncarbonaceous planetesimals accreted from materials that underwent significant thermal processing and thus had relatively low μ84Sr and ɛ54Cr values. Apart from the global trend, the carbonaceous chondrites and noncarbonaceous meteorites both exhibited intrinsic variations that highlight an isotopic dichotomy similar to that observed in other isotope

  19. Strontium Isotope Signals in Cremated Petrous Portions as Indicator for Childhood Origin

    PubMed Central

    Harvig, Lise; Frei, Karin Margarita; Price, T. Douglas; Lynnerup, Niels

    2014-01-01

    Dental enamel is currently of high informative value in studies concerning childhood origin and human mobility because the strontium isotope ratio in human dental enamel is indicative of geographical origin. However, many prehistoric burials involve cremation and although strontium retains its original biological isotopic composition, even when exposed to very high temperatures, intact dental enamel is rarely preserved in cremated or burned human remains. When preserved, fragments of dental enamel may be difficult to recognize and identify. Finding a substitute material for strontium isotope analysis of burned human remains, reflecting childhood values, is hence of high priority. This is the first study comparing strontium isotope ratios from cremated and non-cremated petrous portions with enamel as indicator for childhood origin. We show how strontium isotope ratios in the otic capsule of the petrous portion of the inner ear are highly correlated with strontium isotope ratios in dental enamel from the same individual, whether inhumed or cremated. This implies that strontium isotope ratios in the petrous bone, which practically always survives cremation, are indicative of childhood origin for human skeletal remains. Hence, the petrous bone is ideal as a substitute material for strontium isotope analysis of burned human remains. PMID:25010496

  20. Strontium isotope signals in cremated petrous portions as indicator for childhood origin.

    PubMed

    Harvig, Lise; Frei, Karin Margarita; Price, T Douglas; Lynnerup, Niels

    2014-01-01

    Dental enamel is currently of high informative value in studies concerning childhood origin and human mobility because the strontium isotope ratio in human dental enamel is indicative of geographical origin. However, many prehistoric burials involve cremation and although strontium retains its original biological isotopic composition, even when exposed to very high temperatures, intact dental enamel is rarely preserved in cremated or burned human remains. When preserved, fragments of dental enamel may be difficult to recognize and identify. Finding a substitute material for strontium isotope analysis of burned human remains, reflecting childhood values, is hence of high priority. This is the first study comparing strontium isotope ratios from cremated and non-cremated petrous portions with enamel as indicator for childhood origin. We show how strontium isotope ratios in the otic capsule of the petrous portion of the inner ear are highly correlated with strontium isotope ratios in dental enamel from the same individual, whether inhumed or cremated. This implies that strontium isotope ratios in the petrous bone, which practically always survives cremation, are indicative of childhood origin for human skeletal remains. Hence, the petrous bone is ideal as a substitute material for strontium isotope analysis of burned human remains.

  1. Strontium isotopic geochemistry of the Devils Lake drainage system, North Dakota: A preliminary study and potential paleoclimatic implications

    USGS Publications Warehouse

    Lent, R.M.; Gaudette, H.E.; Lyons, W.B.

    1997-01-01

    A series of water samples (precipitation, surface water and ground water) from the Devils Lake drainage basin in central North Dakota have been analyzed for their ??180 and ??D and 87Sr/86Sr. The ??180 and ??D of snow and most ground water samples fall near the meteoric water line, with the ground water being isotopically heavier than the snow, indicating that a portion of the recharge must come from non-winter precipitation events. One ground water and all the surface water samples fall below the meteoric water line, demonstrating extensive evaporation. The 87Sr/86Sr ratio of the snow is more radiogenic than those of the ground water samples, indicating that the ground water has increased its 86Sr content by the dissolution of mafic rock in the aquifer. Stump Lake has a much inure radiogenic Sr isotopic ratio than the waters of Devils Lake suggesting a source of water different from that of Devils Lake. The East Stump Lake water, on the other hand, appears to be either a mix of Devils Lake and Stump Lake waters, or Devils Lake water diluted with precipitation.

  2. Strontium

    USGS Publications Warehouse

    Ober, J.A.

    1996-01-01

    Part of the Annual Commodities Review 1995. In 1995, U.S. strontium imports and consumption increased nearly 30 percent due to increased domestic production of color television picture tube glass. However, strontium compound exports fell during 1995. Strontium is also used in the production of permanent ceramic ferrite magnets. Strontium nitrate, strontium chromate, and strontium chloride are also commonly used materials. Although the development of an affordable flatscreen display could eliminate the need for strontium in television production, this technology is not expected to be perfected in the immediate future.

  3. Precision in Strontium Isotope Measurements by Laser Ablation Assisted Resonance Ionization Mass Spectrometry

    SciTech Connect

    Sasada, S.; Tomita, H.; Watanabe, K.; Higuchi, Y.; Kawarabayashi, J.; Iguchi, T.

    2009-03-17

    We have investigated the precision of strontium isotope analysis by Laser Ablation-assisted Resonance Ionization Mass Spectrometry(LA-RIMS). We have confirmed that the mass discrimination effect on the {sup 87}Sr/{sup 86}Sr measurement was reduced by the internal correction method. For the present system, the precision of the isotope ratio of {sup 87}Sr/{sup 86}Sr has been estimated to be 0.6%(1{sigma}). The precision has been limited by the fluctuations with a time scale of less than 10 s.

  4. Strontium

    USGS Publications Warehouse

    Ober, J.A.

    2000-01-01

    Mexico is the leading producer of celestite, the most common strontium ore. Chemical Products is the only major US maker of strontium compounds. It produces all of its strontium carbonate from imported Mexican celestite. Mexico is also a large producer of strontium carbonate, as are China, Germany, Japan and the Republic of Korea. There has been no celestite production in the United States since 1959.

  5. Strontium

    USGS Publications Warehouse

    Ober, J.A.

    2006-01-01

    China, Mexico, Spain and Turkey are the world's leading producers of celestite (strontium sulphate). These countries accounted for 98% of the total world production in 2005. For the same period, US apparent consumption of strontium decreased to 12.3 kt. Imports were 21.2 kt, of which 84% came from Mexico. Imports of celestite and strontium carbonate decreased 71% and 24% respectively.

  6. Dendritic network models: Improving isoscapes and quantifying influence of landscape and in-stream processes on strontium isotopes in rivers

    USGS Publications Warehouse

    Brennan, Sean R.; Torgersen, Christian; Hollenbeck, Jeff P.; Fernandez, Diego P.; Jensen, Carrie K; Schindler, Daniel E.

    2016-01-01

    A critical challenge for the Earth sciences is to trace the transport and flux of matter within and among aquatic, terrestrial, and atmospheric systems. Robust descriptions of isotopic patterns across space and time, called “isoscapes,” form the basis of a rapidly growing and wide-ranging body of research aimed at quantifying connectivity within and among Earth's systems. However, isoscapes of rivers have been limited by conventional Euclidean approaches in geostatistics and the lack of a quantitative framework to apportion the influence of processes driven by landscape features versus in-stream phenomena. Here we demonstrate how dendritic network models substantially improve the accuracy of isoscapes of strontium isotopes and partition the influence of hydrologic transport versus local geologic features on strontium isotope ratios in a large Alaska river. This work illustrates the analytical power of dendritic network models for the field of isotope biogeochemistry, particularly for provenance studies of modern and ancient animals.

  7. Dendritic network models: Improving isoscapes and quantifying influence of landscape and in-stream processes on strontium isotopes in rivers

    NASA Astrophysics Data System (ADS)

    Brennan, Sean R.; Torgersen, Christian E.; Hollenbeck, Jeff P.; Fernandez, Diego P.; Jensen, Carrie K.; Schindler, Daniel E.

    2016-05-01

    A critical challenge for the Earth sciences is to trace the transport and flux of matter within and among aquatic, terrestrial, and atmospheric systems. Robust descriptions of isotopic patterns across space and time, called "isoscapes," form the basis of a rapidly growing and wide-ranging body of research aimed at quantifying connectivity within and among Earth's systems. However, isoscapes of rivers have been limited by conventional Euclidean approaches in geostatistics and the lack of a quantitative framework to apportion the influence of processes driven by landscape features versus in-stream phenomena. Here we demonstrate how dendritic network models substantially improve the accuracy of isoscapes of strontium isotopes and partition the influence of hydrologic transport versus local geologic features on strontium isotope ratios in a large Alaska river. This work illustrates the analytical power of dendritic network models for the field of isotope biogeochemistry, particularly for provenance studies of modern and ancient animals.

  8. Strontium

    USGS Publications Warehouse

    Ober, J.A.

    1994-01-01

    Production figures are not published for stronium carbonate because there is only one company producing strontium carbonate domestically. Strontium carbonate is produced in the U.S. from imported celestite. Consumption can be estimated from trade data published by the U.S. Bureau of the Census. Consumption is estimated at approximately 24.5 kt of strontium. The largest end-use of strontium carbonate is in the production of faceplate glass for color television picturetubes. Other applications and markets for strontium are discussed.

  9. Early African Diaspora in colonial Campeche, Mexico: strontium isotopic evidence.

    PubMed

    Price, T Douglas; Tiesler, Vera; Burton, James H

    2006-08-01

    Construction activities around Campeche's central park led to the discovery of an early colonial church and an associated burial ground, in use from the mid-16th century AD to the late 17th century. Remains of some individuals revealed dental mutilations characteristic of West Africa. Analyses of strontium isotopes of dental enamel from these individuals yielded unusually high (87)Sr/(86)Sr ratios, inconsistent with an origin in Mesoamerica, but consistent with an origin in West Africa in terrain underlain by the West Africa Craton, perhaps near the port of Elmina, a principal source of slaves for the New World during the 16th century. These individuals likely represent some of the earliest representatives of the African Diaspora in the Americas.

  10. Progress towards isotope-dependent trapping of strontium

    NASA Astrophysics Data System (ADS)

    Ding, Roger; Camargo, Francisco; Whalen, Joseph D.; Woehl, Germano, Jr.; Dunning, F. Barry; Killian, Thomas C.

    2016-05-01

    Independently controllable trapping potentials for different atomic elements, isotopes, and states are useful for forming quantum degenerate gases through sympathetic cooling, for quantum computing architectures, and for fundamental studies in many-body physics. In strontium, the large isotope shifts (~ 100 MHz) relative to the narrow 1S0 -3P1 intercombination line (7.5 kHz) offers the possibility of creating multi-isotope optical traps in which the potentials are optimized for each individual species, such as 86 Sr with 87 Sr or 86 Sr with 88 Sr, allowing for efficient evaporative cooling. We will present results for confinement of 84 Sr when a dimple is created using far-detuned 689 nm light (Γ / Δ ~10-5) within a large-volume 1064 nm dipole trap (Γ / Δ ~10-7). The 689 nm dimple will be used to develop a trap for efficient creation of 88 Sr Bose-Einstein condensates, overcoming the slow evaporation currently required. Research supported by the AFOSR, the NSF, and the Robert A, Welch Foundation.

  11. Lithostratigraphy, geophysics, biostratigraphy, and strontium-isotope stratigraphy of the surficial aquifer system of eastern Collier County and northern Monroe County, Florida

    USGS Publications Warehouse

    Weedman, S.D.; Paillet, Frederick L.; Edwards, L.E.; Simmons, K.R.; Scott, T.M.; Wardlaw, B.R.; Reese, R.S.; Blair, J.L.

    1999-01-01

    In 1997, ten cores were drilled in eastern Collier County and northern Monroe County, within the limits of the Big Cypress National Preserve. These cores represent a continuation of the study of seven cores in western Collier County begun in 1996 and reported in Weedman and others (1997) and Edwards and others (1998). This joint U.S. Geological Survey and Florida Geological Survey project is designed to acquire subsurface geologic and hydrologic data in southwest Florida to extend current ground-water models, thereby expanding the utility of these models for land and water management. In this report we describe the lithostratigraphy, geophysical logging, sedimentological analysis, dinocyst biostratigraphy, and strontium-isotope stratigraphy of these ten cores. The three geophysical logs (natural gamma-ray, induction conductivity, and neutron porosity) assumed to be related to formation lithology and water quality show that a number of clay-rich zones are present in all of the boreholes, and that pore-water conductivity increases with depth. The clay-rich zones are confirmed by visual examination of core material and sedimentological analysis. The relative transmissivity calculated at 10-foot-thick intervals shows that in six of the boreholes, high values are associated with the shallow aquifer in the 0-40 ft interval. Two of the boreholes (the most northerly and the most easterly) showed relatively higher values of transmissivity in permeable zones at or somewhat below 100 ft in depth. Core geology and logs indicate that the deeper aquifers are not more permeable than similar deeper zones in the other boreholes, but rather that the shallow aquifer appears to be less permeable in these two coreholes. The Arcadia (?) Formation was only penetrated in the deepest core where it is late Miocene in age. The Peace River Formation was penetrated in all but the two westernmost cores. It yields a late Miocene age, based on both dinocysts and strontium-isotope stratigraphy

  12. Seawater strontium isotopes, acid rain, and the Cretaceous-Tertiary boundary

    NASA Technical Reports Server (NTRS)

    Macdougall, J. D.

    1988-01-01

    A large bolide impact at the end of the Cretaceous would have produced significant amounts of nitrogen oxides by shock heating of the atmosphere. The resulting acid precipitation would have increased continental weathering greatly and could be an explanation for the observed high ratio of strontium-87 to strontium-86 in seawater at about this time, due to the dissolution of large amounts of strontium from the continental crust. Spikes to high values in the seawater strontium isotope record at other times may reflect similar episodes.

  13. Neodymium and strontium isotope evidence for crustal contamination of continental volcanics.

    PubMed

    Carter, S R; Evensen, N M; Hamilton, P J; O'nions, R K

    1978-11-17

    Combined neodymium and strontium isotope studies on Tertiary volcanics from northwest Scotland indicate that their parental mantle isotopic compositions have been substantially modified in many instances by contamination with the Precambrian continental crust through which they were erupted. The occurrence of samarium-neodymium and rubidium-strontium "pseudoisochrons" of different ages in these contaminated continental volcanics indicates that they are artifacts of the contamination processes and have no temporal significance with respect to mantle fractionation events.

  14. The Incredible, Embryological Egg: Calcium and Strontium Isotopes Recapitulate Ontogeny

    NASA Astrophysics Data System (ADS)

    Gordon, G. W.; Skulan, J. L.

    2011-12-01

    that caused by osteoporosis in humans. For both mass-dependent Ca and Sr isotopes, the isotopic value of the albumen is the highest natural value yet measured. The offset between the δ88/86Sr values of the albumen and shell is 0.45%, less than half that of the δ44/42Ca offset value (1.29%), as predicted by the relative mass differences. However, the yolk is 0.35% heavier than the shell in δ44/42Ca but 0.70% lighter in δ88/86Sr. In addition, the 87Sr/86Sr value of the shell (0.70854 ±0.000012, 2σ) is statistically the same as the albumen (0.70856 ±0.000018), but slightly offset from the yolk (0.70830 ±0.000014). The apparent decoupling of Ca and Sr, and the radiogenic offset between yolk and shell, may reflect differences in the residence time of calcium and strontium in different reproductive organs, as well as the contribution of medullary bone to shell formation. In addition, it may also reflect differential discrimination against Sr versus Ca in oviduct and uterus. Further studies could extend to thinning eggshells in wild avian populations, biochemical mechanisms of bone formation, and the mechanism of strontium ranelate in the treatment of osteoporosis.

  15. Isotopic composition of lead and strontium from Ascension and Gough Islands

    USGS Publications Warehouse

    Gast, P.W.; Tilton, G.R.; Hedge, C.

    1964-01-01

    Isotopic composition of lead and strontium has been determined in a series of rock samples from two islands on the Mid-Atlantic Ridge. Both inter-and intra-island variations exist in the abundance of radiogenic isotopes of both elements. Lead from basalt of Ascension Island has a Pb206-Pb 204 ratio of 19.5, while the corresponding ratio at Gough Island is only 18.4. The Pb208-Pb204 ratios from the two islands do not differ. Conversely, strontium from basalt of Ascension Island is less radiogenic than that from Gough Island basalts. The trachytes of both islands have lead and strontium that is more radiogenic than that found in the basalts. The inter-island differences indicate the existence of regional variations in the uranium-lead and rubidium-strontium ratios of the upper mantle source of these rocks and show that isotope compositions are a means for investigating chemical heterogeneities in the mantle.

  16. Stable Strontium Isotopic Fractionation During Sorption onto Magnetic Nano-Humid Acid Coated Iron Oxide Particles

    NASA Astrophysics Data System (ADS)

    Liu, H.-C.; You, C.-F.; Tu, Y.-J.

    2012-04-01

    The mobility of strontium (Sr) through hydrological systems is critically governed by sorption reactions of solid phases such as iron oxides and clay minerals. Inorganic precipitated and bacteriogenic iron oxides are widespread in marine and fresh systems fed by iron-rich supplies, which may impact the global Sr cycle. A series of laboratory batch experiments of Sr sorption onto humid acid coated magnetic nano iron oxides using high purity in-house standard were performed in this study and aimed for gaining a better understanding of mechanisms controlling Sr mobility. The results indicate that Sr sorption is a function of pH, 100 % Sr remains unbounded at pH <4 and more than 85 % absorbed at pH >8. Temperature controlled experiments in the range of 5 - 35 degrees C indicate a positive relationship between sorption capacity and temperature. Measurements of stable Sr isotopes (δ88Sr and δ87Sr) in batch experiments show that lighter isotopes reacted preferentially with iron oxides, and a negligible pH effect on isotopic fractionation. To calculate the degree of the kinetic isotope effect, Rayleigh fractionation model is applied to evaluate the isotope fractionation factor, α is 0.99985 at pH 8.17 (equals to Δ88Sr ~ 0.15 ‰). Temperature exerts only minor isotopic fractionation effect and reveals more importance at lower temperatures. This new finding provides crucial information for a detail evaluation of sorption processes in natural environments.

  17. Strontium

    USGS Publications Warehouse

    Ober, J.A.

    2013-01-01

    In 2012, U.S. apparent consumption of strontium (contained in celestite and manufactured strontium compounds) decreased to 16.7 kt (18,400 st) from 17.3 kt (19,100 st) in 2011. Gross weight of imports was 34.3 kt (37,800 st), 86 percent of which originated in Mexico.

  18. Strontium

    USGS Publications Warehouse

    Angulo, M.A.

    2011-01-01

    In 2010, U.S. apparent consumption of strontium (contained in celestite and manufactured strontium compounds) decreased by 11 percent to 10.4 kt (11,460 st) from 11.8 kt (13,000 st) in 2009. Gross weight of imports totaled 20.9 kt (23,000 st), of which 65 percent originated from Mexico.

  19. Strontium

    USGS Publications Warehouse

    ,

    2012-01-01

    In 2011, U.S. apparent consumption of strontium (contained in celestite and manufactured strontium compounds) increased markedly to 18.4 kt (20,300 st) from 10.4 kt (11,500 st) in 2010. Gross weight of imports was 34.4 kt (38,000 st), of which 76 percent originated from Mexico.

  20. Strontium

    USGS Publications Warehouse

    Angulo, M.A.

    2010-01-01

    In 2009, U.S. apparent consumption of strontium (contained in celestite and manufactured strontium compounds) increased to 16 kt (17,600 st) from 10.6 kt (11,700 st) in 2008, an increase of 52 percent. This increase was attributed primarily to an increase in imported celestite. Gross weight of imports totaled 25.3 kt (27,900 st), of which 91 percent came from Mexico. Imports in 2009 were 18 percent more than in 2008. Exports of strontium compounds in 2009 decreased 15 percent to 9.3 kt (10,250 st) from 10.9 kt (12,000 st) in 2008. In 2009, the U.S. Customs value of imported strontium carbonate was 65 cents/kg (29 cents/lb); for strontium nitrate, the unit value was $ 1/kg (45 cents/lb). The unit value of imported celestite, all of which was from Mexico, was about $47/t ($43/st).

  1. Lead and strontium isotopes as indicators for mixing processes of waters in the former mine 'Himmelfahrt Fundgrube', Freiberg (Germany).

    PubMed

    Heidel, Claudia; Tichomirowa, Marion; Matschullat, Jörg

    2007-12-01

    To pinpoint the origin and mixing processes of mine waters, different mine water types from the polymetallic sulphide ore deposit 'Himmelfahrt Fundgrube' (Freiberg, Germany) were analysed by thermal ionisation mass spectrometry using lead and strontium isotope ratios. Results show that the lead isotope composition of different mine waters results from a mixture of at least two sources: released lead from oxidised sulphide ores (mainly galena) and anthropogenic lead from groundwater. Furthermore, there are indications for an additional lead source. Strontium isotopes in mine waters identify at least three different sources: released strontium from weathered host rock (Grey Gneisses), released strontium from weathered gangue carbonates, and probably strontium from anthropogenic inputs. Contrary to former oxygen and sulphur isotope studies, strontium isotope compositions as well as hydrochemical parameters show the important role of gangue carbonates as an element source in mine waters.

  2. Source of Lake Vostok Cations Constrained with Strontium Isotopes

    NASA Astrophysics Data System (ADS)

    Lyons, William; Welch, Kathleen; Priscu, John; Tranter, Martyn; Royston-Bishop, George

    2016-08-01

    Lake Vostok is the largest sub-glacial lake in Antarctica. The primary source of our current knowledge regarding the geochemistry and biology of the lake comes from the analysis of refrozen lake water associated with ice core drilling. Several sources of dissolved ions and particulate matter to the lake have been proposed, including materials from the melted glacier ice, the weathering of underlying geological materials, hydrothermal activity and underlying, ancient evaporitic deposits. A sample of Lake Vostok Type 1 accretion ice has been analyzed for its 87Sr/86Sr signature as well as its major cation and anion and Sr concentrations. The strontium isotope ratio of 0.71655 and the Ca/Sr ratio in the sample strongly indicate that the major source of the Sr is from aluminosilicate minerals from the continental crust. These data imply that at least a portion of the other cations in the Type 1 ice also are derived from continental crustal materials and not hydrothermal activity, the melted glacier ice, or evaporitic sources.

  3. Strontium

    USGS Publications Warehouse

    Ober, J.A.

    1993-01-01

    Part of a special section reviewing the market performance of industrial minerals in 1992. Imports of celestite (strontium ore) reached nearly 45 kt, which represents an increase of 35 percent over 1991. Mexico supplied almost all of the celestite. Nearly 70 percent of the strontium consumed in the U.S. is used in television picture tube faceplate glass to block X-ray emissions.

  4. The IRHUM database - bioavailable strontium isotope ratios of France for geochemical fingerprinting

    NASA Astrophysics Data System (ADS)

    Willmes, Malte; Moffat, Ian; Grün, Rainer; Armstrong, Richard; Kinsley, Les; McMorrow, Linda

    2013-04-01

    Strontium isotope ratios (87Sr/86Sr) are used as a geochemical tracer in a wide range of fields including archaeology, ecology, soil, food and forensic sciences. These applications are based on the principle that strontium isotopic ratios of materials reflect the geological sources of the strontium, which were available during its formation. Geologic regions with distinct strontium isotope ranges, which depend on their age and composition, can be differentiated. A major constraint for current studies is the lack of robust reference maps to evaluate the strontium isotope ratios measured in the samples. The aim of the IRHUM (isotopic reconstruction of human migration) database is to provide a reference map of bioavailable strontium isotope ratios for continental France. The current dataset contains 400 sample locations covering the major geologic units of the Paris and Aquitaine Basin, the Massif Central, and the Pyrenees. At each site soil and plant samples have been collected to cover the whole range of strontium ratios at a specific location. The database is available online at www.rses.anu.edu.au/research-areas/archaeogeochemistry and contains the bioavailable strontium isotope data as well as major and trace element concentrations for soil and plant samples. Strontium isotopes were analysed using a Neptune multi-collector inductively-coupled plasma mass spectrometer (MC-ICP-MS) and elemental concentrations with a Varian Vista Pro Axial ICP-AES (inductively-coupled plasma atomic emission spectrometer). In addition, IRHUM provides spatial context for each sample, including background geology, field observations and soil descriptions. This metadata allows users to evaluate the suitability of a specific data point for their study. The IRHUM database fills an important gap between high resolution studies from specific sites (e.g. archaeological sites), to the very broad geochemical mapping of Europe. Thus it provides an excellent tool to evaluate the regional context

  5. Laser spectroscopy of radioactive barium and strontium isotopes

    SciTech Connect

    Martin, A.G.

    1986-01-01

    An atomic beam system and a high resolution computer controlled dye laser system were developed to perform isotope shift measurements on accelerator-produced radioactive isotopes. Two different techniques were used to transport the radioactive isotopes to the laser interaction region. The first technique was based on the thermalization and deionization of the nuclear reaction products in a helium buffer gas. The reaction products were subsequently transported in the gas to the laser beam along a capillary tube. This technique suffered from problems with chemical reactions between impurities in the buffer gas and the reaction products and proved to be unsuccessful. The second technique was based on the implantation of the reaction products into a metal lattice. Subsequent heating of the metal lattice released the implanted ions from which an atomic beam was formed. The photon burst technique was used to enable detection of the extremely weak atomic beams formed in this manner. Measurements were performed of the known isotope shifts of radioactive /sup 128/Ba and /sup 126/Ba to test the sensitivity of the system. The previously unmeasured isotope shift of radioactive /sup 82/Sr also was determined, and the result obtained was compared to predictions using the droplet model.

  6. Numerical modeling and strontium isotopic signal to assess the arsenic distribution in a low-enthalpy hydrothermal system: the case study of Viterbo geothermal area (Italy)

    NASA Astrophysics Data System (ADS)

    Battistel, M.; Barbieri, M.

    2013-12-01

    Several studies on the groundwater geochemistry of the hydrothermal area west of Viterbo, highlight the presence of arsenic and other trace elements. The groundwater of Viterbo area was used as source of drinking water by about 150,000 local inhabitants, until 2010, when it was prohibited the use by EU due to the high level of arsenic. The hydrogeological setting highlights the presence of a shallow volcanic aquifer (composed by alkaline-potassic volcanics), characterized by fresh waters, limited at its base by the semiconfining marly-calcareous-arenaceous complex and low-permeability clays. To the west of Viterbo, vertical upflows of hot waters (with a temperature between 50 and 64°C), are due to the locally uplifted of evaporitic reservoir, the reduced thickness of the semiconfining layer and the high local geothermal gradient. Current study is focused on news geochemical approaches to defining the conditions which control arsenic mobility in groundwater in the low- enthalpy thermal area of Viterbo, related to the interaction between the volcanic aquifer and the geothermal reservoir. In addition to determinate chemical components and chemical-physical properties (T, pH, electrical conductivity) the study provided the isotopic values of 87Sr/86Sr of Viterbo geothermal area. Geochemical modelling is conducted using Phreeqc. The program monitors the significant species and calculates equilibrium concentrations and the pCO2 at desired temperatures. Investigations were undertaken in the area exhibiting thermal manifestations and in the immediate surroundings. On the basis of major ions and temperature, it is possible to subdivide the waters sampled into three main groups: the thermal waters with a sulphate -alkaline-earth facies, the fresh waters with a biocarbonate-alkaline facies, and a group of mixing waters with a undefined facies. The values of strontium isotopic ratio 87Sr/86Sr marks out the different circuits of groundwater. Values lower than 0.70800 are

  7. Strontium

    Integrated Risk Information System (IRIS)

    Strontium ; CASRN 7440 - 24 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effect

  8. Strontium

    USGS Publications Warehouse

    Ober, J.A.

    2003-01-01

    Mexico and Spain are the leading producers of celestite, the most common strontium ore. Those countries produced nearly 80 percent of the estimated 360 kt (397,000 st) of celestite produced worldwide during 2002. China and Turkey are other significant celestite producers.

  9. Strontium isotopic variations of Neoproterozoic seawater: Implications for crustal evolution

    SciTech Connect

    Asmerom, Y.; Jacobsen, S.B.; Knoll, A.H.; Butterfield, N.J. ); Swett, K. )

    1991-10-01

    The authors report high precision Sr isotopic data on carbonates from the Neoproterozoic Shaler Group, Victoria Island, Northwest Territories, Canada. Samples with low {sup 87}Rb/{sup 86}Sr ratios (<0.01) were selected for Sr isotopic analysis. {delta}{sup 18}O, Mn, Ca, Mg, and Sr data were used to recognize altered samples. The altered samples are characterized by high Mn/Sr ({ge}2) and variable {delta}{sup 18}O; most are dolomites. The data indicate that between ca. 790-850 Ma the {sup 87}Sr/{sup 86}Sr ratio of seawater varied between 0.70676 and 0.70561. The samples show smooth and systematic variation, with the lowest {sup 87}Sr/{sup 86}Sr value of 0.70561 at ca. 830 Ma. The low {sup 87}Sr/{sup 86}Sr ratio of carbonates from the lower parts of the section is similar to a value reported for one sample from the Adrar of Mauritania ({approx}900 Ma), West African Craton. Isotopic ratios from the upper part of the Shaler section are identical to values from the lower part of the Neoproterozoic Akademikerbreen Group, Spitsbergen. Although a paucity of absolute age determinations hinders attempts at the precise correlation of Neoproterozoic successions, it is possible to draw a broad outline of the Sr isotopic composition of seawater for this period. Data from this study and the literature are used to construct a curve of the {sup 87}Sr/{sup 86}Sr ratio of Neoproterozoic seawater. The Sr isotope composition of seawater reflects primarily the balance between continental Sr input through river input and mantle input via hydrothermal circulation of seawater through mid-ocean ridges. Coupling of Nd and Sr isotopic systems allows the authors to model changes in seafloor spreading rates (or hydrothermal flux) and continental erosion. The Sr hydrothermal flux and the erosion rate (relative to present-day value) are modeled for the period 500-900 Ma.

  10. Strontium isotopic variations of Neoproterozoic seawater - Implications for crustal evolution

    NASA Technical Reports Server (NTRS)

    Asmerom, Yemane; Jacobsen, Stein B.; Knoll, Andrew H.; Butterfield, Nicholas J.; Swett, Keene

    1991-01-01

    High-precision Sr isotopic data were obtained on carbonate samples from the Neoproterozoic Shaler Group, Victoria Island (Canada). Results indicate that, between ca. 790 and 850 Ma, the Sr-87/Sr-86 ratio of seawater varied betweeen 0.70676 and 0.70561, with the minimum value at about 830 Ma. A curve of the Sr-87/Sr-86 seawater ratio vs. age showed that the new data substantially improve the existing isotopic record of Sr in seawater for the period 790-850 Ma. The Sr isotopic system data were coupled with data for the Nd isotopic system to model changes in the seafloor spreading rates (hydrothermal flux) and the continental erosion for the period 500-900 Ma. Results indicate that hydrothermal flux reached a maximum value at ca. 830 Ma, while a maximum in erosion rate occurred at ca. 570 Ma. These peaks are considered to be related to the developments in the Pan-African and related orogenic events.

  11. Strontium isotopic variations of Neoproterozoic seawater - Implications for crustal evolution

    NASA Technical Reports Server (NTRS)

    Asmerom, Yemane; Jacobsen, Stein B.; Knoll, Andrew H.; Butterfield, Nicholas J.; Swett, Keene

    1991-01-01

    High-precision Sr isotopic data were obtained on carbonate samples from the Neoproterozoic Shaler Group, Victoria Island (Canada). Results indicate that, between ca. 790 and 850 Ma, the Sr-87/Sr-86 ratio of seawater varied betweeen 0.70676 and 0.70561, with the minimum value at about 830 Ma. A curve of the Sr-87/Sr-86 seawater ratio vs. age showed that the new data substantially improve the existing isotopic record of Sr in seawater for the period 790-850 Ma. The Sr isotopic system data were coupled with data for the Nd isotopic system to model changes in the seafloor spreading rates (hydrothermal flux) and the continental erosion for the period 500-900 Ma. Results indicate that hydrothermal flux reached a maximum value at ca. 830 Ma, while a maximum in erosion rate occurred at ca. 570 Ma. These peaks are considered to be related to the developments in the Pan-African and related orogenic events.

  12. Authentication of bell peppers using boron and strontium isotope compositions

    NASA Astrophysics Data System (ADS)

    Rosner, Martin; Pritzkow, Wolfgang; Vogl, Jochen; Voerkelius, Susanne

    2010-05-01

    The wrong declaration of food in terms of geographical origin and production method is a major problem for the individual consumer and public regulatory authorities. The authentication of food matrices using H-C-N-O-S isotopic compositions is already well established. However, specific questions require additional isotopic systems, which are more diagonstic for the source reservoires involved or production methods used. Here we present B and Sr isotopic compositions of bell peppers from Europe (Germany, Austria, Netherlands, Spain) and Israel to verfiy their origin. The bell peppers' B isotopic compositions between different locations are highly variable (d11BNISTSRM951 -8 to +35 ‰), whereas the 87Sr/86Sr ratios are all close to modern seawater Sr isotopic composition of about 0.7092 (0.7078 to 0.7107), but still can reliably be distinguished. Distinct isotopically heavy and light B isotopic fingerprints are obtained for bell peppers from Israel and the Netherlands. Samples from Germany, Austria, and Spain display overlapping d11B values between 0 and +12 ‰. Bell peppers from Israel show high d11B values (+28 to +35 ‰) combined with 87Sr/86Sr ratios slightly more unradiogenic than modern seawater (ca 0.7079). Bell peppers from the Netherlands, however, show low d11B values (-8 ‰) combinded with 87Sr/86Sr ratios of modern seawater (approx. 0.7085). Mainly based on diagnostic B isotopic compositions bell peppers from Israel and the Netherlands can be related to a specific geographical growing environment (Israel) or production method (Netherlands). The isotope fingerprints of bell peppers from the Netherlands are consistent with growing conditions in greenhouses typical for the Netherlands vegetable farming. Using optimized production methods crops in greenhouses were supplied with nutritients by liquid fertilizers on artificial substrates. As most fertilizers derive from non-marine salt deposits, fertilization typically imprints invariant d11B values close

  13. The IRHUM (Isotopic Reconstruction of Human Migration) database - bioavailable strontium isotope ratios for geochemical fingerprinting in France

    NASA Astrophysics Data System (ADS)

    Willmes, M.; McMorrow, L.; Kinsley, L.; Armstrong, R.; Aubert, M.; Eggins, S.; Falguères, C.; Maureille, B.; Moffat, I.; Grün, R.

    2014-03-01

    Strontium isotope ratios (87Sr / 86Sr) are a key geochemical tracer used in a wide range of fields including archaeology, ecology, food and forensic sciences. These applications are based on the principle that the Sr isotopic ratios of natural materials reflect the sources of strontium available during their formation. A major constraint for current studies is the lack of robust reference maps to evaluate the source of strontium isotope ratios measured in the samples. Here we provide a new data set of bioavailable Sr isotope ratios for the major geologic units of France, based on plant and soil samples (Pangaea data repository doi:10.1594/PANGAEA.819142). The IRHUM (Isotopic Reconstruction of Human Migration) database is a web platform to access, explore and map our data set. The database provides the spatial context and metadata for each sample, allowing the user to evaluate the suitability of the sample for their specific study. In addition, it allows users to upload and share their own data sets and data products, which will enhance collaboration across the different research fields. This article describes the sampling and analytical methods used to generate the data set and how to use and access the data set through the IRHUM database. Any interpretation of the isotope data set is outside the scope of this publication.

  14. The IRHUM (Isotopic Reconstruction of Human Migration) database - bioavailable strontium isotope ratios for geochemical fingerprinting in France

    NASA Astrophysics Data System (ADS)

    Willmes, M.; McMorrow, L.; Kinsley, L.; Armstrong, R.; Aubert, M.; Eggins, S.; Falguères, C.; Maureille, B.; Moffat, I.; Grün, R.

    2013-11-01

    Strontium isotope ratios (87Sr/86Sr) are a key geochemical tracer used in a wide range of fields including archaeology, ecology, food and forensic sciences. These applications are based on the principle that the Sr isotopic ratios of natural materials reflect the sources of strontium available during their formation. A major constraint for current studies is the lack of robust reference maps to evaluate the source of strontium isotope ratios measured in the samples. Here we provide a new dataset of bioavailable Sr isotope ratios for the major geologic units of France, based on plant and soil samples (Pangaea data repository doi:10.1594/PANGAEA.819142). The IRHUM (Isotopic Reconstruction of Human Migration) database is a web platform to access, explore and map our dataset. The database provides the spatial context and metadata for each sample, allowing the user to evaluate the suitability of the sample for their specific study. In addition, it allows users to upload and share their own datasets and data products, which will enhance collaboration across the different research fields. This article describes the sampling and analytical methods used to generate the dataset and how to use and access of the dataset through the IRHUM database. Any interpretation of the isotope dataset is outside the scope of this publication.

  15. Strontium Isotopes as Tracers for Contamination from Potential Marcellus Shale Waters

    NASA Astrophysics Data System (ADS)

    Cai, Z.; Li, L.; Hakala, A.

    2014-12-01

    Mineralogical and geochemical conditions vary significantly in natural water systems, including groundwater aquifers and rivers. In addition, contamination events are often elusive. As a result, it is often challenging to pinpoint the contamination of natural waters by specific types of water sources. The strontium isotope ratio R87Sr, defined as 87Sr/86Sr, has shown promise in discerning contamination from different types of wastewaters related to Marcellus Shale development. The R87Sr of potential end members, including Marcellus shale produced water (0.710-0.712) and Upper Devonian/Lower Mississippian formation brine (0.720-0.721), have been shown to be distinct from those in natural waters. Here we use reactive transport modeling (CrunchFlow) to understand key process and factors that govern the evolution of R87Sr, and the conditions under which we can discern contamination sources in natural water systems. Simulation results show that ion exchange reaction plays an important role in the evolution of R87Sr while release rate has a relatively minor impact on R87Sr evolution. Even with large dilution factor where the volumetric flow rate of natural waters is orders of magnitude higher than the release rates of contamination source water, the R87Sr is still sensitive to different types of source contamination waters. Insights gained here suggest that strontium isotopes can potentially be used as a tracers for different type of water contamination. The modeling tool developed can offer a powerful tool for understanding, predicting, monitoring of natural water contamination.

  16. Strontium isotopic variations of Neoproterozoic seawater: implications for crustal evolution.

    PubMed

    Asmerom, Y; Jacobsen, S B; Knoll, A H; Butterfield, N J; Swett, K

    1991-01-01

    circulation of seawater through mid-ocean ridges. Coupling of Nd and Sr isotopic systems allows us to model changes in seafloor spreading rates (or hydrothermal flux) and continental erosion. The Sr hydrothermal flux and the erosion rate (relative to present-day value) are modeled for the period 500-900 Ma. The results indicate that the hydrothermal flux reached a maximum value at ca. 830 Ma. In contrast, a large peak in erosion rate is indicated at ca. 570 Ma. The peaks in hydrothermal flux and erosion rate are most likely related to developments in the Pan-African and related orogenic events, whose initial development is characterized by production of juvenile crust during supercontinental break up and rifting. The time ca. 570 Ma is characterized by continent-continent collision and production of recycled crust. Sr isotope data from Proterozoic carbonates offer a valuable resource for understanding large-scale crust dynamics.

  17. A preliminary bioavailable strontium isotope soil map of Europe.

    NASA Astrophysics Data System (ADS)

    Hoogewerff, Jurian; Reimann, Clemens; Ueckermann, Henriette; Frei, Robert; Frei, Karin; van Aswegen, Thalita; Stirling, Claudine; Reid, Malcolm; Clayton, Aaron; Gemas Project Team

    2017-04-01

    The GEMAS project collected samples from grazing land (n=2118, 0-20cm depth) and agricultural soil (n=2211, 0-10cm depth) at a scale of 1 site/2500km2 in most of Europe1. Elemental analysis using different extractions (Aqua Regia and MMI), whole soil XRF data and Q-ICPMS lead isotope data have been published1. Here we report high-precision 87Sr/86Sr results for the first 1000+ samples. To best represent Sr in plants and animals an ammonium nitrate soil extraction was chosen2. Samples were measured in three laboratories and shared QC samples demonstrated the robustness of the complete extraction and measurement protocol. Observed 87Sr/86Sr values range from 0.7038 to 0.7597 with the majority of samples centring about the median of 0.7092. Spatial interpolation of the data shows some major trends over Europe with high 87Sr/86Sr in known old intrusive terrains in Scandinavia, Iberia and the Alps. To improve the spatial resolution we investigated relations between measured 87Sr/86Sr values and other parameters for which higher spatial density (interpolated) data exists in geological and lithological databases like IGME50003 and GLiM4. For each sampling site matching geological age data and lithology were obtained by overlaying sampling locations on the IGME5000 and GLiM maps and extracting age and lithology information. All statistical and geospatial manipulations were performed using the R statistical package. Overall the 87Sr/86Sr values show a moderate correlation (Pearson R=0.54) with age but demonstrate varying homogeneity in different lithological units. Within the GEMAS dataset the strontium isotope ratios correlate most strongly with the lead isotope results,206Pb/208Pb (R=0.56) indicating a combined age and "crustalinity" effect. Whole soil Rb (XRF) is slightly higher correlated (R=0.26) with 87Sr/86Sr than extracted Rb (AR) at R=0.12 indicating some influence of the long term Rb signal in the soil parent material. Sodium is the highest correlated whole soil

  18. Effect of sea water interaction on strontium isotope composition of deep-sea basalts

    USGS Publications Warehouse

    Julius, Dasch E.; Hedge, C.E.; Dymond, J.

    1973-01-01

    Analyses of rim-to-interior samples of fresh tholeiitic pillow basalts, deuterically altered holocrystalline basalts, and older, weathered tholeiitic basalts from the deep sea indicate that 87Sr 86Sr ratios of the older basalts are raised by low temperature interaction with strontium dissolved in sea water. 87Sr 86Sr correlates positively with H2O in these basalts; however, there is little detectable modification of the strontium isotope composition in rocks with H2O contents less than 1%. The isotope changes appear to be a function of relatively long-term, low-temperature weathering, rather than high-temperature or deuteric alteration. Strontium abundance and isotopic data for these rocks suggest that strontium content is only slightly modified by interaction with sea water, and it is a relatively insensitive indicator of marine alteration. Average Rb-Sr parameters for samples of apparently unaltered basalt are: Rb = 1.11 ppm; Sr = 132 ppm; 87Sr 86Sr = 0.70247. ?? 1973.

  19. Dissolution rates and vadose zone drainage from strontium isotope measurements of groundwater in the Pasco Basin, WA unconfined aquifer

    SciTech Connect

    Singleton, Michael J.; Maher, Katharine; DePaolo, Donald J.; Conrad, Mark E.; Dresel, P. EVAN

    2006-04-30

    Strontium isotope compositions measured in groundwater samples from 273 wells in the Pasco Basin unconfined aquifer below the Hanford Site show large and systematic variations that provide constraints on groundwater recharge, weathering rates of the aquifer host rocks, communication between unconfined and deeper confined aquifers, and vadose zone-groundwater interaction. This article describes the evaluation of strontium geochemistry of a major aquifer.

  20. Deep burial dolomitization driven by plate collision: Evidence from strontium-isotopes of Jurassic Arab IV dolomites from offshore Qatar

    SciTech Connect

    Vahrenkamp, V.C.; Taylor, S.R. )

    1991-03-01

    The use of strontium-isotope ratios of dolomites to constrain timing and mechanism of diagenesis has been investigated on Jurassic Arab IV dolomites from offshore Qatar. Reservoir quality is determined by two types of dolomites, which were differentiated geochemically (cathodoluminescence, fluid inclusions, and carbon and oxygen stable isotopes): (1) stratigraphically concordant sucrosic dolomites with high porosity formed during early near-surface diagenesis (Jurassic) and (2) stratigraphically discordant cylindrical bodies of massive, porosity-destroying dolomites formed late during deep burial diagenesis (Eocene-Pliocene). Detailed Sr-isotope analysis of dolomites from the Arab IV confirms an Early Jurassic age of the sucrosic, high porosity dolomites ({sup 87}Sr/{sup 86}SR = 0.70707 for NBS 987 = 0.71024) with magnesium and strontium being derived from Jurassic seawater. Late Tertiary compressional orogeny of the Zagros belt to the north is proposed to have caused large-scale squeezing of fluids from the pore system of sedimentary rocks. A regional deep fluid flow system developed dissolving infra-Cambrian evaporites upflow and causing large-scale deep burial dolomitization downflow.

  1. Automated method for simultaneous lead and strontium isotopic analysis applied to rainwater samples and airborne particulate filters (PM10).

    PubMed

    Beltrán, Blanca; Avivar, Jessica; Mola, Montserrat; Ferrer, Laura; Cerdà, Víctor; Leal, Luz O

    2013-09-03

    A new automated, sensitive, and fast system for the simultaneous online isolation and preconcentration of lead and strontium by sorption on a microcolumn packed with Sr-resin using an inductively coupled plasma mass spectrometry (ICP-MS) detector was developed, hyphenating lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA). Pb and Sr are directly retained on the sorbent column and eluted with a solution of 0.05 mol L(-1) ammonium oxalate. The detection limits achieved were 0.04 ng for lead and 0.03 ng for strontium. Mass calibration curves were used since the proposed system allows the use of different sample volumes for preconcentration. Mass linear working ranges were between 0.13 and 50 ng and 0.1 and 50 ng for lead and strontium, respectively. The repeatability of the method, expressed as RSD, was 2.1% and 2.7% for Pb and Sr, respectively. Environmental samples such as rainwater and airborne particulate (PM10) filters as well as a certified reference material SLRS-4 (river water) were satisfactorily analyzed obtaining recoveries between 90 and 110% for both elements. The main features of the LOV-MSFIA-ICP-MS system proposed are the capability to renew solid phase extraction at will in a fully automated way, the remarkable stability of the column which can be reused up to 160 times, and the potential to perform isotopic analysis.

  2. Synopsis of strontium isotope variations in groundwater at Aspo, southern Sweden

    USGS Publications Warehouse

    Peterman, Z.E.; Wallin, B.

    1999-01-01

    Strontium isotope ratios are used to identify end-member ground-water compositions at Aspo in southeastern Sweden where the Hard Rock Laboratory (HRL) has been constructed to evaluate the suitability of crystalline rock for the geologic disposal of nuclear waste. The Hard Rock Laboratory is a decline (tunnel) constructed in 1.8 Ga-old granitic rock that forms islands in an archipelago along the Swedish coast. Ground-water samples were obtained for isotopic analyses from boreholes drilled from the surface and from side boreholes drilled within the HRL. Infiltration at Aspo occurs primarily through fractures zones in the granitic bedrock beneath thin soils throughout the area. Because of extremely low Sr concentrations, rain and snow are not important contributors to the Sr isotope budget of the ground-water system. At shallow levels, water percolating downward along fractures and fracture zones acquires a ??87Sr between +9.5 and +10.0??? and maintains this value downward while Sr concentrations increase by two orders of magnitude. Ground-water samples from both boreholes and from in the HRL show the effects of mixing with saline waters containing as much as 59 mg/L Sr and ??87Sr values as large as +13.92%, Baltic Sea water is a potential component of the groundwater system with ??87Sr values only slightly larger than modern marine values (+0.3???) but with much lower concentrations (1.5 mg/L) than ocean water (8 mg/L). However, because of large Sr concentration differences between the saline groundwater (59 mg/L) and Baltic Sea water (1.5 rag/L), ??87Sr values are not particularly sensitive indicators of sea-water intrusion even though their ??87Sr values differ substantially.

  3. Strontium isotopes delineate fine-scale natal origins and migration histories of Pacific salmon

    PubMed Central

    Brennan, Sean R.; Zimmerman, Christian E.; Fernandez, Diego P.; Cerling, Thure E.; McPhee, Megan V.; Wooller, Matthew J.

    2015-01-01

    Highly migratory organisms present major challenges to conservation efforts. This is especially true for exploited anadromous fish species, which exhibit long-range dispersals from natal sites, complex population structures, and extensive mixing of distinct populations during exploitation. By tracing the migratory histories of individual Chinook salmon caught in fisheries using strontium isotopes, we determined the relative production of natal habitats at fine spatial scales and different life histories. Although strontium isotopes have been widely used in provenance research, we present a new robust framework to simultaneously assess natal sources and migrations of individuals within fishery harvests through time. Our results pave the way for investigating how fine-scale habitat production and life histories of salmon respond to perturbations—providing crucial insights for conservation. PMID:26601173

  4. Strontium isotopes delineate fine-scale natal origins and migration histories of Pacific salmon

    USGS Publications Warehouse

    Brennan, Sean R.; Zimmerman, Christian E.; Fernandez, Diego P.; Cerling, Thure E.; McPhee, Megan V.; Wooller, Matthew J.

    2015-01-01

    Highly migratory organisms present major challenges to conservation efforts. This is especially true for exploited anadromous fish species, which exhibit long-range dispersals from natal sites, complex population structures, and extensive mixing of distinct populations during exploitation. By tracing the migratory histories of individual Chinook salmon caught in fisheries using strontium isotopes, we determined the relative production of natal habitats at fine spatial scales and different life histories. Although strontium isotopes have been widely used in provenance research, we present a new robust framework to simultaneously assess natal sources and migrations of individuals within fishery harvests through time. Our results pave the way for investigating how fine-scale habitat production and life histories of salmon respond to perturbations—providing crucial insights for conservation.

  5. Late Miocene evolution of the Black Sea: insights from palynology and strontium isotope ratios

    NASA Astrophysics Data System (ADS)

    Grothe, Arjen; van Baak, Christiaan; Vasiliev, Iuliana; Sangiorgi, Francesca; Reichart, Gert-Jan; Stoica, Marius; Krijgsman, Wout

    2016-04-01

    During the late Miocene, the connection(s) between the Mediterranean Basin and the Atlantic Ocean deteriorated, which ultimately culminated in thick evaporite deposits and a water level drop in the Mediterranean Basin during the so-called Messinian Salinity Crisis (MSC, 5.97 - 5.33 Ma). It has been claimed that Black Sea, in response to the MSC, also desiccated but these claims have been proven incorrectly. Here we present palynological (dinoflagellate cysts and pollen) and strontium isotope ratios from two Black Sea records: the Zheleznyi Rog outcrop section and Deep Sea Drilling Project Hole 380A. Organic walled cyst-producing dinoflagellates are highly sensitive to even small changes in surface waters and strontium isotope ratios are excellent recorders of changing connectivity. Our records provide therefore more insights in the sensitivity of the Black Sea to Messinian Salinity Crisis and the general evolution of the late Miocene Black Sea.

  6. Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction

    SciTech Connect

    Elizabeth C. Chapman,† Rosemary C. Capo,† Brian W. Stewart,*,† Carl S. Kirby,‡ Richard W. Hammack,§ Karl T. Schroeder,§ and Harry M. Edenborn

    2012-02-24

    Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ∼375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (εSr SW = +13.8 to +41.6, where εSr SW is the deviation of the 87Sr/86Sr ratio from that of seawater in parts per 104); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.

  7. Geochemical and strontium isotope characterization of produced waters from Marcellus Shale natural gas extraction.

    PubMed

    Chapman, Elizabeth C; Capo, Rosemary C; Stewart, Brian W; Kirby, Carl S; Hammack, Richard W; Schroeder, Karl T; Edenborn, Harry M

    2012-03-20

    Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ~375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (ε(Sr)(SW) = +13.8 to +41.6, where ε(Sr) (SW) is the deviation of the (87)Sr/(86)Sr ratio from that of seawater in parts per 10(4)); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.

  8. Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction

    SciTech Connect

    Chapman, Elizabeth C; Capo, Rosemary C.; Stewart, Brian W.; Kirby, Carl S.; Hammack, Richard W.; Schroeder, Karl T.; Edenborn, Harry M.

    2012-03-20

    Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of 375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (ε{sub Sr}{sup SW} = +13.8 to +41.6, where ε{sub Sr}{sup SW} is the deviation of the {sup 87}Sr/{sup 86}Sr ratio from that of seawater in parts per 10{sup 4}); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate between Marcellus Formation produced water and other potential sources of TDS into ground or surface waters.

  9. Application of lead and strontium isotope ratio measurements for the origin assessment of uranium ore concentrates.

    PubMed

    Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Keegan, Elizabeth; Millet, Sylvain

    2009-10-15

    Lead and strontium isotope ratios were used for the origin assessment of uranium ore concentrates (yellow cakes) for nuclear forensic purposes. A simple and low-background sample preparation method was developed for the simultaneous separation of the analytes followed by the measurement of the isotope ratios by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). The lead isotopic composition of the ore concentrates suggests applicability for the verification of the source of the nuclear material and by the use of the radiogenic (207)Pb/(206)Pb ratio the age of the raw ore material can be calculated. However, during data interpretation, the relatively high variation of the lead isotopic composition within the mine site and the generally high contribution of natural lead as technological contamination have to be carefully taken into account. The (87)Sr/(86)Sr isotope ratio is less prone to the variation within one mine site and less affected by the production process, thus it was found to be a more purposeful indicator for the origin assessment and source verification than the lead. The lead and strontium isotope ratios measured and the methodology developed provide information on the initial raw uranium ore used, and thus they can be used for source attribution of the uranium ore concentrates.

  10. Variations in the strontium isotopic composition of seawater during the Neogene

    SciTech Connect

    Hodell, D.A.; Mueller, P.A.; Garrido, J.R. )

    1991-01-01

    The authors report 261 strontium isotopic analyses of well-preserved planktonic foraminifers from three Deep Sea Drilling Project Sites (519, 588, and 607). These samples cover the period from 24 Ma to present with an average of approximately one sample per 100 ka. The combination of high sample density and uniformity of analytical procedures has produced a well-defined record of changes in the {sup 87}Sr/{sup 86}Sr of seawater during the Neogene. The record can be viewed as a series of essentially linear segments with slopes ranging from as high as 6{times}10{sup {minus}5}/m.y. to as low as 0/m.y. The times associated with major inflections in the curve do not appear to correspond to simple geologic phenomena such as eustatic cycles, but are probably controlled by a combination of tectonic and climatic factors that influenced the abundance and isotopic composition of terrestrial strontium input to the oceans. The strontium isotopic data are consistent with a progressive increase in the chemical weathering rates of the continents during the Neogene, probably related to repeated glaciations, increased exposure of continents by lowered sea level, and increased continental relief resulting from high rates of tectonic uplift.

  11. Strontium isotopes correlation of the Tunisian Late Cretaceous Abiod Formation: Comparison to previous biostratigraphic assignments

    NASA Astrophysics Data System (ADS)

    Mabrouk El Asmi, Amina

    2015-11-01

    The Tunisian topmost Le Kef Formation and Abiod Formation were the focus of strontium isotopes numeric age dating. A representative outcrop section in NW Tunisia near Le Kef town (El Djebil section) constituted the main study material. In addition, a small outcrop section (Kodiet ez Zarbia) in NW Tunisia, equivalent of the base of the overlying El Haria Formation, was also examined. Results were compared to previous numeric dating by Mabrouk et al. (2005) of the Aleg (lateral equivalent of Le Kef Formation), Abiod and El Haria formations in four offshore wells from the Miskar Gas Field (Miskar W1, W2, W3, and W4), Gulf of Gabes, SE Tunisia. Strontium isotopes stratigraphy, overall, supports the previous biostratigraphic assignments and indicates that: (i) the age ranges of the Abiod Formation at El Djebil section and in the Miskar Field are very similar; (ii) the age of the Le Kef Formation at El Djebil section is younger than its equivalent Aleg Formation in the Miskar Field; (iii) the El Haria Formation, cored in Miskar W3 and sampled at Kodiet ez Zarbia, is of approximately the same age. The strontium isotopes dating concurs with biostratigraphic assignments and suggest that the Abiod Formation in Miskar W1 (SE) corresponds to most of that occurring at El Djebil section (NW) and is therefore a condensed chalk sequence that was deposited through Campanian-Early Maastrichtian time.

  12. Strontium isotope characterization of wines from Quebec, Canada.

    PubMed

    Vinciguerra, Victor; Stevenson, Ross; Pedneault, Karine; Poirier, André; Hélie, Jean-François; Widory, David

    2016-11-01

    The (87)Sr/(86)Sr isotope ratios were measured on grape, wine and soil samples collected in 13 commercial vineyards located in three major wine producing areas of Quebec (Canada). The soils yield Sr isotope ratios that are intimately related to the local geology and unambiguously discriminate the different producing areas. A strong relationship exists between the (87)Sr/(86)Sr isotope ratios of the wine and the grapes. This suggests that the vinification process does not alter the overall Sr budget. Although the Sr isotope ratios of the grapes do not show a strong correlation with the bulk Sr isotope composition of the soil, they do correlate strongly with the Sr isotope composition contained in the labile fraction of the soil. This indicates that the labile fraction of the soil represents the Sr reservoir available to the plant during its growth. This study demonstrates that the Sr isotope approach can be used as a viable tool in forensic science for investigating the provenance of commercial wines.

  13. STRONTIUM ISOTOPE EVOLUTION OF PORE WATER AND CALCITE IN THE TOPOPAH SPRING TUFF, YUCCA MOUNTAIN , NEVADA

    SciTech Connect

    B.D. Marshall; K. Futa

    2001-02-07

    Yucca Mountain, a ridge of Miocene volcanic rocks in southwest Nevada, is being characterized as a site for a potential high-level radioactive waste repository. One issue of concern for the future performance of the potential repository is the movement of water in and around the potential repository horizon. Past water movement in this unsaturated zone is indicated by fluid inclusions trapped in calcite coatings on fracture footwall surfaces and in some lithophysal cavities. Some of the fluid inclusions have homogenization temperatures above the present-day geotherm (J.F. Whelan, written communication), so determining the ages of the calcite associated with those fluid inclusions is important in understanding the thermal history of the potential repository site. Calcite ages have been constrained by uranium-lead dating of silica polymorphs (opal and chalcedony) that are present in most coatings. The opal and chalcedony ages indicate that deposition of the calcite and opal coatings in the welded part of the Topopah Spring Tuff (TSw hydrogeologic unit) spanned nearly the entire history of the 12.8-million-year-old rock mass at fairly uniform overall long-term rates of deposition (within a factor of five). Constraining the age of a layer of calcite associated with specific fluid inclusions is complicated. Calcite is commonly bladed with complex textural relations, and datable opal or chalcedony may be millions of years older or younger than the calcite layer or may be absent from the coating entirely. Therefore, a more direct method of dating the calcite is presented in this paper by developing a model for strontium evolution in pore water in the TSw as recorded by the strontium coprecipitated with calcium in the calcite. Although the water that precipitated the calcite in fractures and cavities may not have been in local isotopic equilibrium with the pore water, the strontium isotope composition of all water in the TSw is primarily controlled by water

  14. Calcined bone provides a reliable substrate for strontium isotope ratios as shown by an enrichment experiment.

    PubMed

    Snoeck, Christophe; Lee-Thorp, Julia; Schulting, Rick; de Jong, Jeroen; Debouge, Wendy; Mattielli, Nadine

    2015-01-15

    Strontium isotopes ((87) Sr/(86) Sr) are used in archaeological and forensic science as markers of residence or mobility because they reflect the local geological substrate. Currently, tooth enamel is considered to be the most reliable tissue, but it rarely survives heating so that in cremations only calcined bone fragments survive. We set out to test the proposition that calcined bone might prove resistant to diagenesis, given its relatively high crystallinity, as the ability to measure in vivo (87) Sr/(86) Sr from calcined bone would greatly extend application to places and periods in which cremation was the dominant mortuary practice, or where unburned bone and enamel do not survive. Tooth enamel and calcined bone samples were exposed to a (87) Sr-spiked solution for up to 1 year. Samples were removed after various intervals, and attempts were made to remove the contamination using acetic acid washes and ultrasonication. (87) Sr/(86) Sr was measured before and after pre-treatment on a Nu Plasma multi-collector induced coupled plasma mass spectrometer using NBS987 as a standard. The strontium isotopic ratios of all samples immersed in the spiked solution were strongly modified showing that significant amounts of strontium had been adsorbed or incorporated. After pre-treatment the enamel samples still contained significant amounts of (87) Sr-enriched contamination while the calcined bone fragments did not. The results of the artificial enrichment experiment demonstrate that calcined bone is more resistant to post-mortem exchange than tooth enamel, and that in vivo strontium isotopic ratios are retained in calcined bone. Copyright © 2014 John Wiley & Sons, Ltd.

  15. Lead and strontium isotope data for thermal waters of the regional geothermal system in the Twin Falls and Oakley areas, South-Central Idaho

    SciTech Connect

    Mariner, R.H.; Young, H.W.

    1995-12-31

    Thermal fluids obviously related to aquifers in both rhyolite and limestone occur in the Twin Falls-Oakley area of south-central Idaho. Limestone-related waters (high calcium with low silica and fluoride) occur in the middle and upper (southern) parts of the area. Rhyolite-related waters (low calcium but high in silica and fluoride) occur in the lower (northern) part of the area. The relation of thermal fluids in Paleozoic limestone to thermal fluids in Tertiary rhyolite is unknown. Thermal fluids from limestone are dilute, so water-rock reaction in rhyolite could obliterate chemical evidence of fluid residence in a limestone. However, isotopic tracers such as {sup 206}Pb/{sup 204}Pb, {sup 207}Pb/{sup 204}Pb, {sup 208}Pb/{sup 204}Pb, and {sup 87}Sr/{sup 86}Sr might preserve evidence of fluid residence in limestone. Systematic relations between these isotopes and dissolved constituents in the water demonstrate the presence of limestone beneath most if not all of the study area and that aquifers in the limestone and rhyolite are hydrologically connected.

  16. Reconstructing changes in marine carbonate production during the PETM using stable strontium isotopes

    NASA Astrophysics Data System (ADS)

    Pearce, C. R.; Parkinson, I. J.; Foster, L. C.; Schmidt, D. N.

    2012-12-01

    The Palaeocene-Eocene Thermal Maximum (PETM) at ~55Ma represents a global climatic optimum that is characterised by an increase in sea surface temperatures and a co-incident increase in continental weathering rates1-3. It is also associated with an abrupt negative δ13C excursion that is indicative of a large and rapid input of isotopically light carbon into the ocean-atmosphere system4. This sudden release of carbon during the PETM had a major impact on the marine carbonate system, and resulted in the dissolution of carbonates in the deep oceans and associated shoaling of the carbonate compensation depth (ccd) due to a depletion in the availability of the carbonate ion2,5. This study provides new constraints on the changes in the marine carbonate flux during the PETM event using the stable strontium isotope system (δ88/86Sr). The long residence time of Sr in the oceans (~2.5 Ma) means that seawater has an isotopically homogenous δ88/86Sr composition that is dependent on the balance between the principle Sr inputs (rivers, hydrothermal fluids and porewaters) and outputs (incorporation into carbonate)6. Changes in the flux of Sr to the oceans during the PETM can be accounted for using the radiogenic Sr isotope system (87Sr/86Sr), enabling variations in δ88/86Sr to be attributed to shifts in the carbonate output flux. New δ88/86Sr, 87Sr/86Sr and Sr/Ca data from the PETM are presented from well-preserved planktonic foraminifera collected from Shatsky Rise in the Pacific Ocean. Foraminiferal calcite has been demonstrated to preserve the δ88/86Sr composition of seawater7, and all samples were handpicked to ensure that only specific species and size fractions were analysed. The new data is compared to previously reported variations in Sr/Ca ratios from the Pacific Ocean, Southern Ocean and Tropical Atlantic3, and the implications for global carbonate dissolution as a consequence of ocean acidification during the PETM are discussed. (1)Zachos et al. (2003). Science

  17. Stable strontium mass dependent isotopic fractionation in authigenic continental barite

    NASA Astrophysics Data System (ADS)

    Griffith, E. M.; Widanagamage, I. H.; Scher, H. D.; Senko, J.

    2013-12-01

    The use of stable Sr-isotopic measurements (δ88Sr) of barite precipitates from terrestrial environments will be evaluated as a new geochemical proxy to identify mode of barite mineralization for use in earth science applications including understanding similar ancient barite deposits. Stable Sr-isotope measurements of barite and waters from three warm artesian springs in the continental United States where barite precipitates under a variety of conditions (e.g., temperatures, saturation states, microbial communities) will be presented. Initial results show a large range of fractionation factors during barite precipitation from aqueous solution between and within some of the field sites of >0.6 permil. The waters range from δ88Sr = -0.04 to +0.50 permil. The solid barite precipitates that have been separated from the bulk sediment using a modified sequential leaching procedure range from δ88Sr = -0.43 to +0.16 permil. Average 2σ for the isotopic analyses is 0.05 permil, similar to previously published estimates for error on this measurement by MC-ICPMS. Barite is a highly stable and widely-distributed mineral found in magmatic, metamorphic, and sedimentary rocks (of all ages), as well as in soils, aerosol dust, and extraterrestrial material. Establishing the controlling parameters of stable Sr-isotopic fractionation in barite is important as barite may be an ideal vehicle to address critical questions in the earth sciences, including early earth biogeochemistry.

  18. Origins of invasive piscivores determined from the strontium isotope ratio (87Sr/86Sr) of otoliths

    USGS Publications Warehouse

    Wolff, Brian A.; Johnson, Brett M.; Breton, Andre R.; Martinez, Patrick J.; Winkelman, Dana L.; Gillanders, Bronwyn

    2012-01-01

    We examined strontium isotope ratios (87Sr/86Sr) in fish otoliths to determine the origins of invasive piscivores in the Upper Colorado River Basin (UCRB, western USA). We examined 87Sr/86Sr from fishes in different reservoirs, as well as the temporal stability and interspecies variability of 87Sr/86Sr of fishes within reservoirs, determined if 87Sr/86Sr would be useful for "fingerprinting" reservoirs where invasive piscivores may have been escaping into riverine habitat of endangered fishes in the UCRB, and looked for evidence that such movement was occurring. Our results showed that in most cases 87Sr/86Sr was unique among reservoirs, overlapped among species in a given reservoir, and was temporally stable across years. We identified the likely reservoir of origin of river-caught fish in some cases, and we were also able to determine the year of possible escapement. The approach allowed us to precisely describe the 87Sr/86Sr fingerprint of reservoir fishes, trace likely origins of immigrant river fish, and exclude potential sources, enabling managers to focus control efforts more efficiently. Our results demonstrate the potential utility of 87Sr/86Sr as a site-specific and temporally stable marker for reservoir fish and its promise for tracking fish movements of invasive fishes in river-reservoir systems.

  19. CORRELATED STRONTIUM AND BARIUM ISOTOPIC COMPOSITIONS OF ACID-CLEANED SINGLE MAINSTREAM SILICON CARBIDES FROM MURCHISON

    SciTech Connect

    Liu, Nan; Savina, Michael R.; Gallino, Roberto; Davis, Andrew M.; Bisterzo, Sara; Gyngard, Frank; Käppeler, Franz; Cristallo, Sergio; Dauphas, Nicolas; Pellin, Michael J.; Dillmann, Iris

    2015-04-08

    We present strontium, barium, carbon, and silicon isotopic compositions of 61 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing both strontium and barium contamination. For the first time, by using correlated Sr-88/Sr-86 and Ba-138/Ba-136 ratios in mainstream SiC grains, we are able to resolve the effect of C-13 concentration from that of C-13-pocket mass on s-process nucleosynthesis, which points toward the existence of large C-13 pockets with low C-13 concentrations in asymptotic giant branch stars. The presence of such large C-13 pockets with a variety of relatively low C-13 concentrations seems to require multiple mixing processes in parent asymptotic giant branch stars of mainstream SiC grains.

  20. CORRELATED STRONTIUM AND BARIUM ISOTOPIC COMPOSITIONS OF ACID-CLEANED SINGLE MAINSTREAM SILICON CARBIDES FROM MURCHISON

    SciTech Connect

    Liu, Nan; Davis, Andrew M.; Dauphas, Nicolas; Pellin, Michael J.; Savina, Michael R.; Gallino, Roberto; Bisterzo, Sara; Gyngard, Frank; Käppeler, Franz; Cristallo, Sergio; Dillmann, Iris

    2015-04-10

    We present strontium, barium, carbon, and silicon isotopic compositions of 61 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing both strontium and barium contamination. For the first time, by using correlated {sup 88}Sr/{sup 86}Sr and {sup 138}Ba/{sup 136}Ba ratios in mainstream SiC grains, we are able to resolve the effect of {sup 13}C concentration from that of {sup 13}C-pocket mass on s-process nucleosynthesis, which points toward the existence of large {sup 13}C pockets with low {sup 13}C concentrations in asymptotic giant branch stars. The presence of such large {sup 13}C pockets with a variety of relatively low {sup 13}C concentrations seems to require multiple mixing processes in parent asymptotic giant branch stars of mainstream SiC grains.

  1. Strontium isotope study of coal utilization by-products interacting with environmental waters.

    PubMed

    Spivak-Birndorf, Lev J; Stewart, Brian W; Capo, Rosemary C; Chapman, Elizabeth C; Schroeder, Karl T; Brubaker, Tonya M

    2012-01-01

    Sequential leaching experiments on coal utilization by-products (CUB) were coupled with chemical and strontium (Sr) isotopic analyses to better understand the influence of coal type and combustion processes on CUB properties and the release of elements during interaction with environmental waters during disposal. Class C fly ash tended to release the highest quantity of minor and trace elements-including alkaline earth elements, sodium, chromium, copper, manganese, lead, titanium, and zinc-during sequential extraction, with bottom ash yielding the lowest. Strontium isotope ratios ((87)Sr/(86)Sr) in bulk-CUB samples (total dissolution of CUB) are generally higher in class F ash than in class C ash. Bulk-CUB ratios appear to be controlled by the geologic source of the mineral matter in the feed coal, and by Sr added during desulfurization treatments. Leachates of the CUB generally have Sr isotope ratios that are different than the bulk value, demonstrating that Sr was not isotopically homogenized during combustion. Variations in the Sr isotopic composition of CUB leachates were correlated with mobility of several major and trace elements; the data suggest that arsenic and lead are held in phases that contain the more radiogenic (high-(87)Sr/(86)Sr) component. A changing Sr isotope ratio of CUB-interacting waters in a disposal environment could forecast the release of certain strongly bound elements of environmental concern. This study lays the groundwork for the application of Sr isotopes as an environmental tracer for CUB-water interaction. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Strontium Isotope Study of Coal Untilization By-products Interacting with Environmental Waters

    SciTech Connect

    Spivak-Birndorf, Lev J; Stewart, Brian W; Capo, Rosemary C; Chapman, Elizabeth C; Schroeder, Karl T; Brubaker, Tonya M

    2011-09-01

    Sequential leaching experiments on coal utilization by-products (CUB) were coupled with chemical and strontium (Sr) isotopic analyses to better understand the influence of coal type and combustion processes on CUB properties and the release of elements during interaction with environmental waters during disposal. Class C fly ash tended to release the highest quantity of minor and trace elements—including alkaline earth elements, sodium, chromium, copper, manganese, lead, titanium, and zinc—during sequential extraction, with bottom ash yielding the lowest. Strontium isotope ratios ({sup 87}Sr/{sup 86}Sr) in bulk-CUB samples (total dissolution of CUB) are generally higher in class F ash than in class C ash. Bulk-CUB ratios appear to be controlled by the geologic source of the mineral matter in the feed coal, and by Sr added during desulfurization treatments. Leachates of the CUB generally have Sr isotope ratios that are different than the bulk value, demonstrating that Sr was not isotopically homogenized during combustion. Variations in the Sr isotopic composition of CUB leachates were correlated with mobility of several major and trace elements; the data suggest that arsenic and lead are held in phases that contain the more radiogenic (high-{sup 87}Sr/{sup 86}Sr) component. A changing Sr isotope ratio of CUB-interacting waters in a disposal environment could forecast the release of certain strongly bound elements of environmental concern. This study lays the groundwork for the application of Sr isotopes as an environmental tracer for CUB–water interaction.

  3. Strontium isotope detection of brine contamination in the East Poplar oil field, Montana

    USGS Publications Warehouse

    Peterman, Zell E.; Thamke, Joanna N.; Futa, Kiyoto; Oliver, Thomas A.

    2010-01-01

    Brine contamination of groundwater in the East Poplar oil field was first documented in the mid-1980s by the U.S. Geological Survey by using hydrochemistry, with an emphasis on chloride (Cl) and total dissolved solids concentrations. Supply wells for the City of Poplar are located downgradient from the oil field, are completed in the same shallow aquifers that are documented as contaminated, and therefore are potentially at risk of being contaminated. In cooperation with the Office of Environmental Protection of the Fort Peck Tribes, groundwater samples were collected in 2009 and 2010 from supply wells, monitor wells, and the Poplar River for analyses of major and trace elements, including strontium (Sr) concentrations and isotopic compositions. The ratio of strontium-87 to strontium-86 (87Sr/86Sr) is used extensively as a natural tracer in groundwater to detect mixing among waters from different sources and to study the effects of water/rock interaction. On a plot of the reciprocal strontium concentration against the 87Sr/86Sr ratio, mixtures of two end members will produce a linear array. Using this plotting method, data for samples from most of the wells, including the City of Poplar wells, define an array with reciprocal strontium values ranging from 0.08 to 4.15 and 87Sr/86Sr ratios ranging from 0.70811 to 0.70828. This array is composed of a brine end member with an average 87Sr/86Sr of 0.70822, strontium concentrations in excess of 12.5 milligrams per liter (mg/L), and chloride concentrations exceeding 8,000 mg/L mixing with uncontaminated water similar to that in USGS06-08 with 18.0 mg/L chloride, 0.24 mg/L strontium, and a 87Sr/86Sr ratio of 0.70811. The position of samples from the City of Poplar public-water supply wells within this array indicates that brine contamination has reached all three wells. Outliers from this array are EPU-4G (groundwater from the Cretaceous Judith River Formation), brine samples from disposal wells (Huber 5-D and EPU 1-D

  4. Strontium isotope variation in the dissolved load and suspended sediments of Northern Hemisphere land terminating glaciers

    NASA Astrophysics Data System (ADS)

    Stevenson, E. I.; Aciego, S.; Arendt, C. A.; Sheik, C.; Das, S. B.

    2014-12-01

    Bedrock, hydrology and microbial communities are primary contributors to sub-glacial chemical weathering and therefore mediate the chemical composition of bulk glacial outflow. Chemical weathering associated with glaciers has attracted attention due to the possible link between increased chemical weathering during glacial retreat and control of the marine radiogenic strontium (87Sr/86Sr) ratios [1-3]. Here we contrast the differences in strontium isotope (87Sr/86Sr) compositions of the dissolved load (DL) and suspended sediments (SS) from bulk subglacial outflows from three, northern hemisphere ice masses. We sampled from sub-glacial outflows draining geographically and geologically distinct glacial termini from the (1) the South, East and West of the Greenland Ice sheet (GIS), (2) the Juneau Icefield and (3) the Columbia Icefield. The diversity in regional outlet facilitates the comparison of glaciers with differing climate, size, hydrology and bedrock. The magnitude of offset in 87Sr/86Sr ratios between the SS and DL (Δ87/86Sr, ‰, = (87Sr/86SrSS - 87Sr/86SrDL)*1000) varies between -62 to +7 ‰ and shows a positive correlation with pH, regardless of differences in glacier size and bedrock lithology. Here we believe the magnitude of the offset between the DL and SS is due to variations in subglacial weathering environments driven primarily by residence times of both water and sediment within the glacial system, and secondarily by bedrock lithology. The most radiogenic Sr compositions (both DL and SS) are found draining the GIS (up to 87Sr/86Sr = 0.80716) indicating the GIS may have provided a significant source of radiogenic Sr to the oceans during times of deglaciation. [1] Armstrong, R.L., (1971) Nature, v. 230, p. 132-133 [2] Capo, R.C., De Paolo, D.J., (1990) Science, v. 249, no. 4964, p. 51-55. [3] Vance, D., Teagle, D.A.H., Foster, G.L. (2009), Nature, v. 458 p. 493-496.

  5. Strontium isotope evidence for a highly mobile population on the Pamir Plateau 2500 years ago

    NASA Astrophysics Data System (ADS)

    Wang, Xueye; Tang, Zihua; Wu, Jing; Wu, Xinhua; Wu, Yiqun; Zhou, Xinying

    2016-10-01

    Archeological researches have proposed arguments for human mobility and long-distance trading over the Eurasia before the Silk Roads. Here we utilize biologically available strontium isotope analysis to assess the extent of pre-Silk Road population movements and cultural communications across the Asian interior. From an early Iron Age cemetery (ca. 2500 yr B.P.) on the eastern Pamir Plateau, mean 87Sr/86Sr ratios from 34 individuals display considerable isotopic variability, and 10 individuals are distinguished as migrants based on the local strontium isotope range of 0.710296–0.710572 defined by 12 ovicaprine bones. Comparison of the proportion (10/34) with the regional census data completed in 1909 A.D. (3% non-locals) suggests a highly migratory behavior on the plateau 2500 years ago. Furthermore, exotic mortuary objects, such as silk fabrics from eastern China and angular harp originated from the Near East, clearly demonstrate an interaction between different cultures on the plateau before the establishment of the Silk Road.

  6. Strontium isotope evidence for a highly mobile population on the Pamir Plateau 2500 years ago

    PubMed Central

    Wang, Xueye; Tang, Zihua; Wu, Jing; Wu, Xinhua; Wu, Yiqun; Zhou, Xinying

    2016-01-01

    Archeological researches have proposed arguments for human mobility and long-distance trading over the Eurasia before the Silk Roads. Here we utilize biologically available strontium isotope analysis to assess the extent of pre-Silk Road population movements and cultural communications across the Asian interior. From an early Iron Age cemetery (ca. 2500 yr B.P.) on the eastern Pamir Plateau, mean 87Sr/86Sr ratios from 34 individuals display considerable isotopic variability, and 10 individuals are distinguished as migrants based on the local strontium isotope range of 0.710296–0.710572 defined by 12 ovicaprine bones. Comparison of the proportion (10/34) with the regional census data completed in 1909 A.D. (3% non-locals) suggests a highly migratory behavior on the plateau 2500 years ago. Furthermore, exotic mortuary objects, such as silk fabrics from eastern China and angular harp originated from the Near East, clearly demonstrate an interaction between different cultures on the plateau before the establishment of the Silk Road. PMID:27762330

  7. Isotopic ratios and release rates of strontium measured from weathering feldspars

    NASA Astrophysics Data System (ADS)

    Brantley, S. L.; Chesley, J. T.; Stillings, L. L.

    1998-05-01

    also argue that abraded feldspar particles formed naturally, for example, during glaciation, will show this initial transient nonstoichiometric release. However, once the transient release is completed (perhaps 10 2 to 10 3 yr after abrasion), as long as the solution chemistry remains relatively constant, stoichiometric release of cations from feldspars, including Sr, is expected. The most likely way, therefore, to increase riverine fluxes of major cations or radiogenic 87Sr/ 86Sr is to create highly flushed (and, therefore, far from equilibrium) water-rock systems such as glacial sediments and soils, with reactive minerals (e.g., carbonate, plagioclase, or biotite) containing significant radiogenic strontium.

  8. Rubidium-strontium isotope characteristics of lunar soils.

    NASA Technical Reports Server (NTRS)

    Cliff, R. A.; Lee-Hu, C.; Wetherill, G. W.

    1972-01-01

    Evaluation of K, Rb, and Sr concentrations and Sr isotopic composition for hand-picked fractions from the 175- to 1000-micron Apollo 12 fines samples 12032 and 12070 and for two less than 1-mm bulk fines samples, 14163,160 and 14259,21, from Apollo 14 which have model Rb-Sr ages close to 4.6 b.y. The Apollo 14 data indicate the presence of a radiogenic component of 4.6 b.y. model age like the Apollo 12 fines, confirming a very early geochemical differentiation of the moon. Progressively greater enrichment in K and Rb relative to the bulk fines is shown by microbreccia from both samples, ropy brown glass from 12032, and light-grey lithic fragments from 12032. Model Rb-Sr ages, based on a basaltic achondrite initial ratio, are generally close to 4.6 b.y. The microbreccias and ropy brown glass have model ages that are younger but indistinguishable from 4.6 b.y. within analytical error. Light grey lithic fragments from 12032 have a model age of 5.1 b.y. and must have had a multistage Rb/Sr evolution. The data are broadly compatible with two-component mixing models of the Apollo 12 fines. On the basis of modal composition, the microbreccia is considered the major nonbasaltic constituent.

  9. Chemical and strontium isotope characterization of rainwater in Beijing, China

    NASA Astrophysics Data System (ADS)

    Xu, Zhifang; Han, Guilin

    Major ion concentrations and Sr isotope ratios ( 87Sr/ 86Sr) were measured in rainwater samples collected at an urban site in Beijing over a period of one year. The pH value and major ion concentrations of samples varied considerably, and about 50% of the rainwater studied here were acidic rain with pH values less than 5.0. Ca 2+ and NH 4+ were the dominant cations in rainwaters and their volume weighted mean (VWM) values were 608 μeq l -1 (14-1781 μeq l -1) and 186 μeq l -1 (48-672 μeq l -1), respectively. SO 42- was the predominant anion with VWM value of 316 μeq l -1 (65-987 μeq l -1), next was NO 3- with VWM value of 109 μeq l -1 (30-382 μeq l -1). Using Na as an indicator of marine origin, and Al for the terrestrial inputs, the proportions of sea salt and terrestrial elements were estimated from elemental ratios. More than 99% of Ca 2+ and 98% of SO 42- in rainwater samples are non-sea-salt origin. The 87Sr/ 86Sr ratios were used to characterize the different sources based on the data sets of this study and those from literatures. Such sources include sea salts ( 87Sr/ 86Sr˜0.90917), soluble soil dust minerals originating from either local or the desert and loess areas (˜0.7111), and anthropogenic sources (fertilizers, coal combustion and automobile exhausts). The high concentrations of alkaline ions (mainly Ca 2+) in Beijing atmosphere have played an important role to neutralize the acidity of rainwater. However, it is worth noting that there is a remarkable acidification trend of rainwater in Beijing recent years.

  10. In-situ Strontium Isotopes Analysis on Single Conodont Apatite by LA-MC-ICP-MS

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Zhang, L.; Chen, Z. Q.; Ma, D.; Qiu, H.; Lv, Z.; Hu, Z.; Wang, F.

    2014-12-01

    Strontium isotope played an important role in stratigraphic chronology and sedimentary geochemistry research (McArthur et al., 2001). Conodonts is a kind of extinct species of marine animals and widely distributed in marine sediments all over the world. Rich in radiogenic Sr contents and difficulty to be affected during diagenesis alteration makes conodonts a good choice in seawater Sr isotope composition studies (John et al., 2008). Conodont samples were collected from 24th to 39th layer across Permian-Triassic boundary at Meishan D section (GSSP), Zhejiang Province, South China (Yin et al., 2001). Conodonts was originated from fresh limestone and only conodont elements with CAI<2 were chosen for in-situ strontium isotope analysis using laser-ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). Conodont samples are from totally 25 layers in seven conodont zones making it possible for a high resolution 87Sr/ 86Sr curve reconstruction during the Permian-Triassic transition. 87Sr/ 86Sr ratio kept a relatively high value (0.70752) in the middle part of the Clarkina yini zone and a lower value (0.70634) in the upperpart of Clarkina taylorae zone. Of which, 87Sr/ 86Sr ratio emerged a rapid decrease within the Clarkina taylorae zone. After a subsequent increase, 87Sr/ 86Sr ratio dropped to 0.70777 in the Isarcicella staeschei zone. These results helps providing reference data for the biological mass extinction events during the Permian-Triassic transition. Our study also makes is possible for high resolution 87Sr/ 86Sr ratio testing on the single conodont apatite and riched the in-situ studies on the conodont apatite, which of great significance for the future conodont Sr isotope research (Zhao et al., 2009; Zhao et al., 2013). Keywords: Conodonts, Strontium isotope, LA-MC-ICP-MS, Permian-Triassic transition, Meishan D section [1] John et al., 2008 3P[2] McArthur et al., 2001 J. of Geology [3] Yin et al., 2001 Episodes [4] Zhao et al

  11. Diffusion as a Rate Limiting Factor on the Evolution of Strontium Isotope Ratios in Fractured Rock

    NASA Astrophysics Data System (ADS)

    Johnson, E. G.; Holt, R. M.; McLing, T. L.

    2002-12-01

    In recent years, several approaches have been developed to model the evolution of strontium isotope ratios (87Sr/86Sr) in porous media. In fractured rock, however, diffusion limits the rates of reaction between mobile water and mineral surfaces inside fracture-bounded blocks. Diffusion can limit transfer of fluids with differing isotopic ratios between the mobile and immobile zones leading to longer equilibration times. We develop a diffusion-based mathematical approach for modeling the evolution of ratios that includes sorption, ion exchange, and dissolution in fracture bounded blocks of multiple sizes. Traditional models employing isotopic ratios with the advection-dispersion equation are unable to incorporate diffusion because they are limited by the structure of their equation. Modeling the individual isotopic species separately accounts for the effects of diffusion. The general governing equation is robust in that it does not assume chemical equilibrium reactions. Special cases show the importance of diffusion-limited mass transfer on the evolution of isotopes ratios in fractured rock.

  12. Enhancement of ferromagnetism by oxygen isotope substitution in strontium ruthenate SrRuO3

    PubMed Central

    Kawanaka, Hirofumi; Aiura, Yoshihiro; Hasebe, Takayuki; Yokoyama, Makoto; Masui, Takahiko; Nishihara, Yoshikazu; Yanagisawa, Takashi

    2016-01-01

    The oxygen isotope effect of the ferromagnetic transition in itinerant ferromagnet strontium ruthenate SrRuO3 with a Curie temperature Tc of 160 K is studied. We observed for the first time a shift of ∆Tc ~ 1 K by oxygen isotope substitution of 16O → 18O in SrRuO3 by precise measurements of DC and AC magnetizations. The results surprisingly lead to the noteworthy inverse isotope effect with negative coefficient α = −∂ lnTc/∂ lnM. The Raman spectra indicate that the main vibration frequency of 16O at 363 cm−1 shifts to 341 cm−1 following oxygen isotope substitution 18O. This shift is remarkably consistent with the Debye frequency being proportional to ∝ 1√M where M is the mass of an oxygen atom. The positive isotope shift of ∆Tc can be understood by taking account of the electron-phonon interaction. PMID:27739475

  13. Tracking mobility using human hair: What can we learn from lead and strontium isotopes?

    PubMed

    Vautour, Geneviève; Poirier, André; Widory, David

    2015-01-01

    The isotope ratios of strontium (Sr) and lead (Pb) in water derive from local geology and their isotopic signature can be linked to the age and type of underlying bedrocks and soils (if applicable), and are transferred up the food-chain. Both elements are transferred to human blood through diet and water, and some of it will ultimately be incorporated into the hair structure, making Sr and Pb isotopes interesting tools for tracing human mobility. In this study, we analyzed both the elemental concentration and isotope ratios of Sr and Pb from four different women of different ages to monitor their permanent relocation from central France to Eastern Canada during the summer 2012. For comparison, we also characterized bulk hair samples of sedentary individuals and local tap waters from their regions of origin and of settlement. Our results indicate that the 87Sr/86Sr and 206Pb/204Pb ratios are significantly modified by the change of environment, but also confirm that human hair compositions are impacted by other external factors (such as dust). Sr and Pb isotope systematics demonstrate their added value for detecting human mobility, but require further studies to better constrain the main sources and processes controlling their respective budgets in human hair for provenancing purposes. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  14. Shifting sediment sources in the world's longest river: A strontium isotope record for the Holocene Nile

    NASA Astrophysics Data System (ADS)

    Woodward, Jamie; Macklin, Mark; Fielding, Laura; Millar, Ian; Spencer, Neal; Welsby, Derek; Williams, Martin

    2015-12-01

    We have reconstructed long-term shifts in catchment sediment sources by analysing, for the first time, the strontium (Sr) and neodymium (Nd) isotope composition of dated floodplain deposits in the Desert Nile. The sediment load of the Nile has been dominated by material from the Ethiopian Highlands for much of the Holocene, but tributary wadis and aeolian sediments in Sudan and Egypt have also made major contributions to valley floor sedimentation. The importance of these sources has shifted dramatically in response to global climate changes. During the African Humid Period, before c. 4.5 ka, when stronger boreal summer insolation produced much higher rainfall across North Africa, the Nile floodplain in northern Sudan shows a tributary wadi input of 40-50%. Thousands of tributary wadis were active at this time along the full length of the Saharan Nile in Egypt and Sudan. As the climate became drier after 4.5 ka, the valley floor shows an abrupt fall in wadi inputs and a stronger Blue Nile/Atbara contribution. In the arid New Kingdom and later periods, in palaeochannel fills on the margins of the valley floor, aeolian sediments replace wadi inputs as the most important secondary contributor to floodplain sedimentation. Our sediment source data do not show a measurable contribution from the White Nile to the floodplain deposits of northern Sudan over the last 8500 years. This can be explained by the distinctive hydrology and sediment delivery dynamics of the upper Nile basin. High strontium isotope ratios observed in delta and offshore records - that were previously ascribed to a stronger White Nile input during the African Humid Period - may have to be at least partly reassessed. Our floodplain Sr records also have major implications for bioarchaeologists who carry out Sr isotope-based investigations of ancient human remains in the Nile Valley because the isotopic signature of Nile floodplain deposits has shifted significantly over time.

  15. Seasonal and Spatial Variations of Stable Strontium Isotope in the Suspended Sediments of the Changjiang ( Yangtze) River

    NASA Astrophysics Data System (ADS)

    WANG, X.; Yang, S.; Wei, G.

    2014-12-01

    In recent years, remarkable stable strontium fractionation has been found in many geological and biological processes such as chemical weathering and carbonate precipitation. The stable strontium isotope (δ88/86Sr) compositions in various natural materials have been studied, yet its behavior in river water and sediment remains to be clarified. The Changjiang is the largest river originating from the Tibetan Plateau, and bridges the Eurasian continent and East Asian marginal sea by delivering a large volume of dissolved and particulate materials into the sea. It has complicated tributary system and source rock types and is subject to strong Asian monsoon impacts, which makes it an ideal river for the study of sediment weathering, recycling and source-to-sink transport processes. In this study, spatial and seasonal suspended sediments were collected from the Changjiang mainstream by filtering with 0.45 μm Millipore membrane in the field. The seasonal samples were taken from Datong hydrological station in the lower reaches during a whole hydrological year. All these samples were dissolved with 4N HNO3 to separate them into two different phases: leachate and residue. The stable strontium isotope ratios in these two phases were analyzed using SSB method described in Ma et al. (2013) with MC-ICP-MS. The reference material was SRM 987. The external precision of our method is ±0.013‰ (1SD). The results show that δ88/86Sr values in the residue phase are much higher (0.071-1.172‰) than those in the leachate phase (0.133-0.281‰). Together with major and trace elemental data, we suggest that heavy Sr prefers to enrich in the silicates, rather than carbonate minerals, during the fractionation process. Regular variations of δ88/86Sr are observed in the spatial samples, with the leachates showing overall decreasing trends towards the lower reaches. The values of δ88/86Sr are higher in the flood season than in the dry season. We infer that parent rock types, sediment

  16. Neodymium and strontium isotopic constraints on soil sources in Barbados, West Indies

    NASA Astrophysics Data System (ADS)

    Borg, Lars E.; Banner, Jay L.

    1996-11-01

    Neodymium and strontium isotopic compositions and Sm/Nd ratios are used to constrain the sources of silicate-rich soils developed on uplifted Pleistocene coral-reef limestones on Barbados, West Indies. The geographic and geologic setting of Barbados facilitates the application of these tracers to the evaluation of the following soil sources: (1) Pleistocene reef limestone regolith, (2) Tertiary carbonate rocks, sandstones, and mudstones that are exposed in northeastern Barbados, (3) volcanic ash erupted from the Lesser Antilles arc, (4) Saharan dust transported by trade winds, and (5) fertilizer. The soils have ɛNd values that range from -6.6 to -1.9, 87Sr /86Sr values of 0.70890 to 0.71067, and Sm/Nd ratios of 0.223-0.260. The Pleistocene limestone component is the most significant source of Sr in the soils and a negligible source of Nd. Comparison of Sm and Nd concentrations and neodymium isotopic compositions of soil samples that are weathered to varying extents indicates that Sm and Nd are relatively unfractionated and retained in the soils during weathering. ɛNd and Sm/Nd variations in the soils, therefore, primarily reflect the compositions and proportions of the silicate sources. Mass balance calculations based on SmNd systematics require that the silicate soil components contain between 30-85% volcanic ash, with the remaining silicate fraction comprised of old, continentally-derived sediment. In contrast to Sm and Nd, Sr is mobilized and removed from the soils during weathering. Strontium from volcanic and carbonate sources is preferentially removed relative to continental silicate sources. The strontium isotopic compositions of the soils, therefore, reflect the combined effects of the degree of weathering and the compositions and proportions of the soil sources. Mass balance calculations indicate that at least 35-60% of the initial Sr in the soils has been removed by weathering. These results illustrate (1) the utility of radiogenic isotopes in

  17. Strontium Isotopes of Gaskiers Cap Carbonate, Avalon, Newfoundland: Sequential Digestion Aids Interpretation of Petrologic Complexity

    NASA Astrophysics Data System (ADS)

    Tang, T.; Raub, T. D.; Wang, Z.

    2013-12-01

    Strontium isotope chemostratigraphy in limestones appear to track a near monotonic rising trend from the tail of the breakup of the supercontinent Rodinia at ~750 Ma into the latest Ediacaran Period at ~ 550 Ma (Halverson et al., 2007). This offers a potentially powerful tool to date carbonates occurring within this time period of stepwise environmental oxidation. Furthermore, aspects of the Snowball Earth hypothesis predict that some magnitude of 87Sr/86Sr excursions of seawater is expected at multiple intervals during this time, because balancing influences from prolonged synglacial hydrothermal input in entombed oceans, deglacial freshwater plumes of varying temperature and salinity, and enhanced postglacial silicate weathering from the continents can leave multiple isotopic trends plausible during these critical intervals. The positions of these deglaciations appear to correlate specifically to marine oxidation events, with cause/effect relations still under investigation. To capitalize on all of these interpretive possibilities, it is crucial to establish a high-precision and high-resolution strontium chemostratigraphic record over both short and long timescales. However, difficulties in establishing such a record based on carbonates are associated with 1) diagenetic influence over extensive geological time; and 2) petrologic complexities of the studied samples. Using a sequential digestion technique, Liu et al. (2013) demonstrated that these hurdles can be overcome, and that primary 87Sr/86Sr ratios of contemporaneous seawater can be obtained from Marinoan cap dolostones (~635 Ma), which have considerably less Sr than limestones, and whose Sr isotope compositions are commonly ignored in the strontium chemostratigraphic record. This leads to several viable, specific interpretations about the origin of Marinoan cap carbonate: either 1) very fast deposition; 2) slow deposition in a long-Sr-residence-time ocean; 3) mid-cap deposition in a freshwater "Glacial Lake

  18. Strontium Adsorption and Desorption Reactions in Model Drinking Water Distribution Systems

    DTIC Science & Technology

    2014-02-04

    RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (Include area code) 11-04-2014 Journal Article Strontium adsorption and desorption reactions in model... strontium (Sr2+) adsorption to and desorption from iron corrosion products were examined in two model drinking water distribution systems (DWDS...used to control Sr2; desorption. calcium carbonate; drinking water distribution system; α-FeOOH; iron; strontium ; XANES Unclassified

  19. Strontium stable isotope behaviour in foraminiferal calcite and the retrieval of marine records

    NASA Astrophysics Data System (ADS)

    Stevenson, E.; Burton, K.; Rickaby, R.; Parkinson, I. J.; Anand, P.; Hathorne, E.

    2009-12-01

    The stable strontium (88Sr/86Sr) isotope composition of seawater recorded in sedimentary foraminifera potentially provides key information on variations in the composition of material delivered by continental weathering to the oceans and on changes in carbonate productivity over time. However, recent studies suggest a significant temperature dependent fractionation of Sr stable isotopes during the precipitation of calcium carbonate, which must be quantified before seawater records can be accurately retrieved [1, 2]. This study presents high-precision stable Sr isotope data (±10 ppm 2 s.d.) for core-top planktonic foraminifera from sites in the South Atlantic with a range of annual sea surface temperatures of 18 - 28°C, and preliminary data for quaternary marine foraminiferal records from the SE Indian Ocean. These results indicate that there is no signficiant variation in the stable isotope composition of an individual species across the temperature range studied here, but there are resolvable differences in the offset from seawater between species. In this case, seawater stable Sr isotope records can be reconstructed without the necessity of a temperature correction. The preliminary results for a glacial-interglacial planktonic foraminifera record indicate that there are no resolvable variations in the stable isotope ratios over this time interval, indicating that there are no significant variations in the Sr isotope composition of continental runoff or carbonate productivity in the oceans over this time interval. [1] Fietzke, J., Eisenhauer, A. (2006), Geochem. Geophys. Geosyst., 7, (8), 1-6 . [2] Ruggerburg, A., Fietzke, J., Liebetrau, V. Eisenhauer, A., Dullo, W-C., Freiwald, A. (2008). Earth Plan. Sci. Lett. 269, 570-575

  20. Boron and strontium isotopic characterization of coal combustion residuals: validation of new environmental tracers.

    PubMed

    Ruhl, Laura S; Dwyer, Gary S; Hsu-Kim, Heileen; Hower, James C; Vengosh, Avner

    2014-12-16

    In the U.S., coal fired power plants produce over 136 million tons of coal combustion residuals (CCRs) annually. CCRs are enriched in toxic elements, and their leachates can have significant impacts on water quality. Here we report the boron and strontium isotopic ratios of leaching experiments on CCRs from a variety of coal sources (Appalachian, Illinois, and Powder River Basins). CCR leachates had a mostly negative δ(11)B, ranging from -17.6 to +6.3‰, and (87)Sr/(86)Sr ranging from 0.70975 to 0.71251. Additionally, we utilized these isotopic ratios for tracing CCR contaminants in different environments: (1) the 2008 Tennessee Valley Authority (TVA) coal ash spill affected waters; (2) CCR effluents from power plants in Tennessee and North Carolina; (3) lakes and rivers affected by CCR effluents in North Carolina; and (4) porewater extracted from sediments in lakes affected by CCRs. The boron isotopes measured in these environments had a distinctive negative δ(11)B signature relative to background waters. In contrast (87)Sr/(86)Sr ratios in CCRs were not always exclusively different from background, limiting their use as a CCR tracer. This investigation demonstrates the validity of the combined geochemical and isotopic approach as a unique and practical identification method for delineating and evaluating the environmental impact of CCRs.

  1. A two century record of strontium isotopes from an ice core drilled at Mt Blanc, France

    NASA Astrophysics Data System (ADS)

    Burton, G. R.; Rosman, K. J. R.; Van de Velde, K. P.; Boutron, C. F.

    2006-08-01

    New techniques which allow small amounts of Sr to be reliably analysed [G.R. Burton, V.I. Morgan, C.F. Boutron, K.J.R. Rosman, High-sensitivity measurements of strontium isotopes in polar ice, Anal. Chim. Acta 469 (2002) 225-233] by TIMS (Thermal Ionisation Mass Spectrometry) have been used to measure the isotopic composition of Sr and the concentration of Rb and Sr at sub-nanogram per gram levels in a Mt Blanc snow and ice core. This two century time series of Sr isotopes is the first to be reported in an Alpine glacier. The Sr and Rb concentrations range from 3 ng/g to 20 pg/g and 1 ng/g to 10 pg/g, respectively, with higher concentrations evident in more recent times. This trend is consistent with that reported previously for other metals such as Cd, Cu and Zn [K. Van de Velde, C. Barbante, G. Cozzi, I. Moret, T. Bellomi, C. Ferrari, C. Boutron, Changes in the occurrence of silver, gold, platinum, palladium and rhodium in Mont Blanc ice and snow since the 18th century, Atmos. Environ. 34 (2000) 3117-3127; K. Van de Velde, C. Boutron, C. Ferrari, T. Bellomi, C. Barbante, S. Rudnev, M. Bolshov, Seasonal variations of heavy metals in the 1960s Alpine ice: sources versus meteorological factors, Earth Planet. Sci. Lett. 164 (1998) 521-533; K.J.R. Rosman, C. Ly, K. Van de Velde, C.F. Boutron, A two century record of lead isotopes in high altitude Alpine snow and ice, Earth Planet. Sci. Lett. 176 (2000) 413-424]. The 87Sr/ 86Sr ratios vary between 0.7020 and 0.7176 and display relatively larger variations in recent times which have been attributed to seasonal variations made evident by the increased sampling resolution available at shallower depths. No change with time is evident in this ratio which has a mean value of ˜ 0.712 and is similar to Glacial ice at Summit Greenland, suggesting that aerosols reaching Mt Blanc represent the same mixture of sources. Also, anthropogenic sources would appear to have the same isotopic ratio. The presence of Saharan dust in some

  2. Strontium isotopic geochemistry of the volcanic rocks and associated megacrysts and inclusions from Ross Island and vicinity, Antarctica

    USGS Publications Warehouse

    Stuckless, J.S.; Ericksen, R.L.

    1976-01-01

    Twelve whole-rock samples of volcanic rocks and a composite of 11 basanitoid samples from Ross Island and vicinity, Antarctica show a narrow range of 87Sr/86Sr ratios from 0.70305 to 0.70339. This range is consistent with a model of differentiation from a single parent magma, but the data allow a 30% variation in the 87Rb/86Sr ratio in the source region if the average ratio is less than 0.057 and if the source region has existed as a closed system for 1.5 b.y. Megacrysts of titaniferous augite, kaersutite, and anorthoclase are isotopically indistinguishable from the host volcanic rocks and therefore are probably cogenetic with the volcanic sequence. A single trachyte sample is isotopically distinct from the rest of the volcanic rocks and probably was contaminated with crustal strontium. Ultramafic and mafic nodules found in association with basanitoids and trachybasalts have 87Sr/86Sr ratios ranging from 0.70275 to 0.70575. Several of these nodules exhibit evidence of reaction with the melt and are isotopically indistinguishable from their hosts, but data for seven granulite-facies nodules show an apparent isochronal relationship. Although this isochron may be fortuitous, the resulting age of 158??22 m.y. is similar to ages reported for the voluminous Ferrar Dolerites, and suggests isotopic re-equilibration within the lower crust and upper mantle. These nodules are not genetically related to the Ferrar Dolerites, as evidenced by their lower initial 87Sr/86Sr ratios. Three ultramafic nodules are texturally and isotopically distinct from the rest of the analyzed nodules. These are friable, have larger 87Sr/86Sr ratios, and may represent a deeper sampling of mantle rock than the granulite-facies nodules. They were, however, derived at a shallower depth than the alkalic magma. Thus they are not genetically related to either the magma or the granulite-facies nodules. ?? 1976 Springer-Verlag.

  3. The strontium isotope seawater curve during the early Middle Miocene and its relation to paleoceanographic events

    SciTech Connect

    Hodell, D.A. . Dept. of Geology); Woodruff, F. . Dept. Geological Sciences)

    1992-01-01

    Breaks in slope of the strontium isotope seawater curve signal fundamental changes in either rates of continental weathering, seafloor spreading (i.e., tectonic reorganizations), or submarine dissolution of marine carbonates. The authors conducted a detailed study of the change in slope of the strontium isotopic seawater curve that occurred during the early middle Miocene in three Pacific DSDP sites (289, 574, and 588). The change in slope from the rapid rise in Sr-87/Sr-86 of the early Miocene (60 ppm/Ma) to the less rapid increase of the mid- and late Miocene (22 ppm/Ma) occurred between two periods of maximum [delta]C-13 values dated between 15.5 and 15.2 Ma. This internal was followed by relatively constant Sr-87/Sr-86 values (averaging 0.70878) between 15.2 and 14.2 Ma. Sr-87/Sr-86 ratios began to increase again after 14.2 Ma, but at a reduced rate compared to the early Miocene. The break in slope in Sr-87/Sr-86 preceded the mid-Miocene increase in [delta]O-18 that represents ice growth on Antarctica, which began at 14.9 Ma and increased rapidly after 14.2 Ma. In 2 out of 3 of the sites, the break in Sr-slope between 15.5 and 15.2 Ma is accompanied by a small, but significant, decrease in Sr-87/Sr-86 values. They speculate, that this decrease in Sr-87/Sr-86 may have been related to massive dissolution of older carbonate on the sea floor associated with NH2B (Neogene Hiatus 2 of Keller and Barron, 1983). This event may have important implications for changes in carbonate chemistry of the oceans. Numerical modeling of the strontium isotope budget will be used to test the feasibility of this mechanism and to estimate the volume and age of dissolved carbonate needed to produce the observed decrease in Sr-87/Sr-86.

  4. Geographic Variation of Strontium and Hydrogen Isotopes in Avian Tissue: Implications for Tracking Migration and Dispersal

    PubMed Central

    Sellick, Megan J.; Kyser, T. Kurt; Wunder, Michael B.; Chipley, Don; Norris, D. Ryan

    2009-01-01

    Background Isotopes can provide unique solutions to fundamental problems related to the ecology and evolution of migration and dispersal because prior movements of individuals can theoretically be tracked from tissues collected from a single capture. However, there is still remarkably little information available about how and why isotopes vary in wild animal tissues, especially over large spatial scales. Methodology/Principal Findings Here, we describe variation in both stable-hydrogen (δDF) and strontium (87Sr/86SrF) isotopic compositions in the feathers of a migratory songbird, the Tree Swallow (Tachycineta bicolor), across 18 sampling sites in North America and then examine potential mechanisms driving this variation. We found that δDF was correlated with latitude of the sampling site, whereas 87Sr/86SrF was correlated with longitude. δDF was related to δD of meteoric waters where molting occurred and 87Sr/86SrF was influenced primarily by the geology in the area where feathers were grown. Using simulation models, we then assessed the utility of combining both markers to estimate the origin of individuals. Using 13 geographic regions, we found that the number of individuals correctly assigned to their site of origin increased from less than 40% using either δD or 87Sr/86Sr alone to 74% using both isotopes. Conclusions/Significance Our results suggest that these isotopes have the potential to provide predictable and complementary markers for estimating long-distance animal movements. Combining isotopes influenced by different global-scale processes may allow researchers to link the population dynamics of animals across large geographic ranges. PMID:19266102

  5. Large volume injection in ion chromatography Separation of rubidium and strontium for on-line inductively coupled plasma mass spectrometry determination of strontium isotope ratios.

    PubMed

    García-Ruiz, Silvia; Moldovan, Mariella; García Alonso, J Ignacio

    2007-05-18

    Large volume injection, up to 5 mL, was evaluated and optimised for the on-line ion chromatographic separation of Rb and Sr before ICP-MS measurement of Sr isotope ratios. Flat-topped chromatographic peaks, ideally suited for multicollector ICP-MS isotope ratio measurements, could be obtained when the composition of the mobile phase (nitric acid and 18-crown-6 ether) was identical to the matrix of the sample. Under those conditions rubidium eluted at the dead volume of the column while strontium produced a flat-topped transient signal with several minutes of stable plateau. On-line data acquisition during several minutes at the plateau of Sr signal allowed high precision Sr isotope ratio measurement. The developed procedure was evaluated for Sr isotope ratio measurements on different types of samples, including cider, apples, apple leaves, and soil extracts, in the frame of a long-term project aiming at origin authentication using strontium isotope ratio measurements. It was observed that sample matrix caused broadening of the strontium chromatographic peak and loss of flat-topped peak profile. Under those circumstances the addition of the complexing crown-ether 18-crown-6 both to samples and chromatographic eluent provided two distinct advantages. First, a drastic increase in the retention of strontium was observed which could be modulated by increasing the concentration of nitric acid in the eluent up to 900 mM. This increase in the eluent HNO(3) concentration allowed the application of the method to acid soil digests and other high acidity samples. Second, the matrix of the sample did not affect any more the chromatographic peak profile and similar chromatographic separations could be obtained for samples and standards maintaining the flat-topped Sr peak profile. Sample preparation consisted of a simple 1:10 dilution of the cider or pre-treated solid samples by adding HNO(3) (900 mM) and 18-crown-6 ether (5mM) to obtain similar composition in the sample solution

  6. Scale of human mobility in the southern Andes (Argentina and Chile): A new framework based on strontium isotopes.

    PubMed

    Barberena, Ramiro; Durán, Víctor A; Novellino, Paula; Winocur, Diego; Benítez, Anahí; Tessone, Augusto; Quiroga, María N; Marsh, Erik J; Gasco, Alejandra; Cortegoso, Valeria; Lucero, Gustavo; Llano, Carina; Knudson, Kelly J

    2017-10-01

    The goal of this article is to assess the scale of human paleomobility and ecological complementarity between the lowlands and highlands in the southern Andes during the last 2,300 years. By providing isotope results for human bone and teeth samples, we assess a hypothesis of "high residential mobility" suggested on the basis of oxygen isotopes from human remains. We develop an isotopic assessment of human mobility in a mountain landscape combining strontium and oxygen isotopes. We analyze bone and teeth samples as an approach to life-history changes in spatial residence. Human samples from the main geological units and periods within the last two millennia are selected. We present a framework for the analysis of bioavailable strontium based on the combination of the geological data with isotope results for rodent samples. The (87) Sr/(86) Sr values from human samples indicate residential stability within geological regions along life history. When comparing strontium and oxygen values for the same human samples, we record a divergent pattern: while δ(18) O values for samples from distant regions overlap widely, there are important differences in (87) Sr/(86) Sr values. Despite the large socio-economic changes recorded, (87) Sr/(86) Sr values indicate a persisting scenario of low systematic mobility between the different geological regions. Our results suggest that strontium isotope values provide the most germane means to track patterns of human occupation of distinct regions in complex geological landscapes, offering a much higher spatial resolution than oxygen isotopes in the southern Andes. © 2017 Wiley Periodicals, Inc.

  7. Variations in the neodymium and strontium isotopic composition and REE content of molluscan shells from the Cretaceous Western Interior seaway

    SciTech Connect

    Whittaker, S.G.; Kyser, T.K. )

    1993-08-01

    Rare earth element concentrations, [epsilon][sub ND](T) values, and strontium isotopic compositions of mollusc shells were used to trace variations in the neodymium and strontium isotopic composition of the epicontinental Late Cretaceous Western Interior seaway of North America. Rare earth element patterns are different in aragonite and calcite produced by the molluscs endemic to the seaway, indicating that either mineralogical control or possibly scavenging by organic films associated with the different phases of biogenic carbonate resulted in differential partitioning of the REEs from seawater during shell formation. The biogenic carbonate also may contain REEs associated with Fe-flocs trapped in the shells during growth, but these flocs cannot result in different REE patterns of aragonite and calcite produced by the molluscs. The neodymium isotopic composition of the Western Interior seaway is inferred to have varied 13 [epsilon]-units over 20 My as a result of incursions of seawater from the Arctic Ocean and Gulf of Mexico, river influx from tectonically active terranes, benthic diagenetic fluxes, and volcanic ash falls. Ash from a variety of volcanic centers in western North America was significant in producing rapid and marked changes in [sup 143]Nd/[sup 144]Nd ratios of the seaway, and abrupt regional variations in neodymium isotopic composition of the seaway make the construction of an accurate neodymium isotope evolution curve difficult for this basin. Strontium isotopic compositions of the mollusc shells indicate the [sup 87]Sr/[sup 86]Sr ratio of the Western Interior seaway was generally similar to contemporaneous oceans, although, periodically, the basin had strontium isotopic compositions distinct from contemporaneous seawater. 58 refs., 7 figs., 3 tabs.

  8. Ion microprobe measurement of strontium isotopes in calcium carbonate with application to salmon otoliths

    USGS Publications Warehouse

    Weber, P.K.; Bacon, C.R.; Hutcheon, I.D.; Ingram, B.L.; Wooden, J.L.

    2005-01-01

    The ion microprobe has the capability to generate high resolution, high precision isotopic measurements, but analysis of the isotopic composition of strontium, as measured by the 87Sr/ 86Sr ratio, has been hindered by isobaric interferences. Here we report the first high precision measurements of 87Sr/ 86Sr by ion microprobe in calcium carbonate samples with moderate Sr concentrations. We use the high mass resolving power (7000 to 9000 M.R.P.) of the SHRIMP-RG ion microprobe in combination with its high transmission to reduce the number of interfering species while maintaining sufficiently high count rates for precise isotopic measurements. The isobaric interferences are characterized by peak modeling and repeated analyses of standards. We demonstrate that by sample-standard bracketing, 87Sr/86Sr ratios can be measured in inorganic and biogenic carbonates with Sr concentrations between 400 and 1500 ppm with ???2??? external precision (2??) for a single analysis, and subpermil external precision with repeated analyses. Explicit correction for isobaric interferences (peak-stripping) is found to be less accurate and precise than sample-standard bracketing. Spatial resolution is ???25 ??m laterally and 2 ??m deep for a single analysis, consuming on the order of 2 ng of material. The method is tested on otoliths from salmon to demonstrate its accuracy and utility. In these growth-banded aragonitic structures, one-week temporal resolution can be achieved. The analytical method should be applicable to other calcium carbonate samples with similar Sr concentrations. Copyright ?? 2005 Elsevier Ltd.

  9. Thermal effects on rare earth element and strontium isotope chemistry in single conodont elements

    NASA Astrophysics Data System (ADS)

    Armstrong, H. A.; Pearson, D. G.; Griselin, M.

    2001-02-01

    A low-blank, high sensitivity isotope dilution, ICP-MS analytical technique has been used to obtain REE abundance data from single conodont elements weighing as little as 5 μg. Sr isotopes can also be measured from the column eluants enabling Sr isotope ratios and REE abundance to be determined from the same dissolution. Results are comparable to published analyses comprising tens to hundreds of elements. To study the effects of thermal metamorphism on REE and strontium mobility in conodonts, samples were selected from a single bed adjacent to a basaltic dyke and from the internationally used colour alteration index (CAI) "standard set." Our analyses span the range of CAI 1 to 8. Homogeneous REE patterns, "bell-shaped" shale-normalised REE patterns are observed across the range of CAI 1 to 6 in both sample sets. This pattern is interpreted as the result of adsorption during early diagenesis and could reflect original seawater chemistry. Above CAI 6 REE patterns become less predictable and perturbations from the typical REE pattern are likely to be due to the onset of apatite recrystallisation. Samples outside the contact aureole of the dyke have a mean 87Sr/ 86Sr ratio of 0.708165, within the broad range of published mid-Carboniferous seawater values. Our analysis indicates conodonts up to CAI 6 record primary geochemical signals that may be a proxy for ancient seawater.

  10. Stable isotopes of lead and strontium as tracers of sources of airborne particulate matter in Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Dewan, Nitika; Majestic, Brian J.; Ketterer, Michael E.; Miller-Schulze, Justin P.; Shafer, Martin M.; Schauer, James J.; Solomon, Paul A.; Artamonova, Maria; Chen, Boris B.; Imashev, Sanjar A.; Carmichael, Greg R.

    2015-11-01

    Central Asia is dominated by an arid climate and desert-like conditions, leading to the potential for long-range transport of desert dust within and out of the region. Of particular interest is the Aral Sea, which has receded in size largely due to water diversion. As a result, newly exposed sediments are resuspended by wind and thus, may be a potential new source of particulate matter within the region. Here, strontium and lead stable isotope ratios are employed along with detailed elemental composition, to explore the contribution of long-range transport of Aral Sea sediments, as well as other potential sources of dust, within Central Asia. Ambient PM10 samples were collected during dust and non-dust events from mid-2008 to mid-2009 at two sites in Kyrgyzstan located ∼1200 and 1500 km ESE of the Aral Sea. Aral Sea sediments and local Kyrgyzstan soils were resuspended and sized to PM10. The Aral Sea sediments have an average 87Sr/86Sr ratio of 0.70992. In contrast, the Sr isotope ratio in local soils exhibits an average ratio of 0.71579. Ambient PM10 collected in Kyrgyzstan has an average 87Sr/86Sr ratio of 0.71177, falling between the values of these two potential sources and indicating a complex mixture of contributing sources. At both sites, airborne Sr isotope ratios measured during dust events were similar, suggesting that Aral Sea sediments only minimally affect air quality in Kyrgyzstan. Elemental analysis and Pb isotope ratios supported this finding. While the Pb isotopes and elemental data both indicate an anthropogenic source, long-range dust transport from other deserts inside and outside the region cannot be ruled out as sources of PM10 in Central Asia.

  11. Strontium Isotopes in Pore Water as an Indicator of Water Flux at the Proposed High-Level Radioactive Waste Repository, Yucca Mountain, Nevada

    SciTech Connect

    B. Marshall; K. Futa

    2004-02-19

    The proposed high-level radioactive waste repository at Yucca Mountain, Nevada, would be constructed in the high-silica rhyolite (Tptp) member of the Miocene-age Topopah Spring Tuff, a mostly welded ash-flow tuff in the {approx}500-m-thick unsaturated zone. Strontium isotope compositions have been measured in pore water centrifuged from preserved core samples and in leachates of pore-water salts from dried core samples, both from boreholes in the Tptp. Strontium isotope ratios ({sup 87}Sr/{sup 86}Sr) vary systematically with depth in the surface-based boreholes. Ratios in pore water near the surface (0.7114 to 0.7124) reflect the range of ratios in soil carbonate (0.7112 to 0.7125) collected near the boreholes, but ratios in the Tptp (0.7122 to 0.7127) at depths of 150 to 370 m have a narrower range and are more radiogenic due to interaction with the volcanic rocks (primarily non-welded tuffs) above the Tptp. An advection-reaction model relates the rate of strontium dissolution from the rocks with flow velocity. The model results agree with the low transport velocity ({approx}2 cm per year) calculated from carbon-14 data by I.C. Yang (2002, App. Geochem., v. 17, no. 6, p. 807-817). Strontium isotope ratios in pore water from Tptp samples from horizontal boreholes collared in tunnels at the proposed repository horizon have a similar range (0.7121 to 0.7127), also indicating a low transport velocity. Strontium isotope compositions of pore water below the proposed repository in core samples from boreholes drilled vertically downward from tunnel floors are more varied, ranging from 0.7112 to 0.7127. The lower ratios (<0.7121) indicate that some of the pore water in these boreholes was replaced by tunnel construction water, which had an {sup 87}Sr/{sup 86}Sr of 0.7115. Ratios lower than 0.7115 likely reflect interaction of construction water with concrete in the tunnel inverts, which had an {sup 87}Sr/{sup 86}Sr < 0.709. These low Sr ratios indicate penetration of

  12. A 7500-year strontium isotope record from the northwestern Nile delta (Maryut lagoon, Egypt)

    NASA Astrophysics Data System (ADS)

    Flaux, Clément; Claude, Christelle; Marriner, Nick; Morhange, Christophe

    2013-10-01

    During the Holocene, delta evolution has been collectively mediated by relative sea-level changes, continental hydrology and human impacts. In this paper, we present a strontium isotope record from the Maryut lagoon (northwestern Nile delta) to quantify the interplay between relative sea-level variations and Nile flow changes during the past 7500 years. 87Sr/86Sr stratigraphy allows five hydrological stages to be defined. (1) The marine transgression of the area is dated to ˜7.5 ka cal. BP, with a clear marine 87Sr/86Sr signature (0.70905-0.7091). (2) Between ˜7 and ˜5.5 ka, in the context of the so-called African Humid Period (AHP), freshwater inputs became progressively predominant in the Maryut's hydrology. Deceleration of sea-level rise coupled with high Nile discharge induced coastal progradation which led to the progressive closure of the Maryut lagoon. (3) Between ˜5.5 and ˜3.8 ka, the end of the AHP is translated by a progressive hydrological shift from a Nile-dominated to a marine-dominated lagoon (87Sr/86Sr shifts from 0.70865 to 0.7088 to 0.70905-0.70915). (4) From ˜2.8 to ˜1.7 ka, 87Sr/86Sr ratios shift towards lower values (0.7084). Although this change is not precisely resolved because of a hiatus in the Maryut's sedimentary record, the 87Sr/86Sr transition from sea-like to Nile-dominated values is attributed to irrigation practices since the early Ptolemaic period (i.e. since ˜2.3 ka), including the Alexandria canal which played a key role in isolating the Maryut from the Mediterranean sea. (5) The final phase of the record covers the period between ˜1.7 and ˜0.2 ka. 87Sr/86Sr ratios indicate high freshwater inputs (from 0.7080 to 0.7085), except between 1.2 and 1.1 to ˜0.7 ka, when a Maryut lowstand and seawater intrusion are attested. In modern times, the Nile's coastal lagoons have been increasingly supplied by freshwater linked to the diversion of waters from the two Nile branches into the irrigation system. It is suggested that this

  13. Strontium isotopes provide clues for a process shift in base cation dynamics in young volcanic soils

    NASA Astrophysics Data System (ADS)

    Bingham, N.; Jackson, M. G.; Bookhagen, B.; Maher, K.; Chadwick, O.

    2015-12-01

    Despite advances in soil development theory based on studies of old soils or over long timescales, little is known about soil thresholds (dramatic changes in soil properties associated with only small shifts in external forcing factors) that might be expressed in young soils (less than 10 kyr). Therefore, we seek to understand infant soil development in a tropical environment through the sourcing of plant available base cations by measuring the strontium (Sr) isotopic composition of the soil exchange complex. Our sampling strategy spans soils in three different precipitation ranges (950-1060 mm, 1180-1210 mm, and 1450-1500) and an array of soil ages from 500 to 7500 years in the Kona region on the island of Hawaii. In Hawaiian soils, 87Sr/86Sr values are determined by a mixture of three components: a mantle-derived component from the lava (0.7034), a rainfall component (0.7093) and a component from continental dust (0.720). Elevation-controlled leaching intensity in the wettest localities produces a decline in the concentration of base cations supplied by basalt and a dilute resupply by rainfall. In the driest sites, where leaching intensity is dramatically reduced, there is a buildup of rainfall-derived extractable Sr in the soil over time. Slow rock weathering rates produce a small rock-derived cation input to the soil. Thus, Sr isotope signatures reflect both the input of rainfall-derived cations and rock-derived cations with values that fall between rainfall and basaltic signatures. Soils in the intermediate precipitation range have Sr isotopic signatures consistent with both the wet and dry trends; suggesting that they lie close to the critical precipitation amount that marks a shift between these two processes. For the Kona region, this transition seems to occur at 1200 mm /yr. In contrast to the clear-cut differentiation in strontium isotopes with precipitation shifts observed in older soils, patterns on these young soils in Kona are complicated by low soil

  14. Stratigraphic implications of trace element and strontium-isotope analyses of Kimmeridgian shell calcite from the Lower Saxony Basin, Germany

    NASA Astrophysics Data System (ADS)

    Zuo, Fanfan; Heimhofer, Ulrich; Huck, Stefan; Erbacher, Jochen; Bodin, Stephane

    2017-04-01

    Stratigraphic uncertainties due to the lack of open marine marker fossils (e.g. ammonites) hamper the precise age assignment and stratigraphic correlation of Kimmeridgian strata found in the Lower Saxony Basin of Northern Germany. Correlation of these deposits with the Jurassic standard ammonite zonation is still difficult, since the existing ostracod biostratigraphy is facies-controlled and of only limited stratigraphic precision. In this study, a chemostratigraphic approach has been chosen and biogenic shell material produced by brachiopods, oysters and lithiotids is evaluated for its reliability to act as proxy of the original Jurassic seawater strontium isotope composition. Low-Mg calcite shells have been collected from three stratigraphic sections accessible in open-cast quarries located in the Lower Saxony Basin of Northern Germany. In order to identify diagenetically altered shell calcite, trace element and stable isotope analysis of 227 calcite samples (oysters=101; brachiopods=60; Trichites=52) has been carried out. The geochemical results reveal that (1) concentration of different trace elements varies between the different groups of shell-forming organisms, which may be related to vital effects and (2) high strontium contents, low Mn and Fe contents and the lack of correlation between these elements indicate near-pristine calcite shells, and therefore shells are supposed to record the ambient sea water composition during the Late Jurassic. Strontium-isotope (87Sr/86Sr) analysis of diagenetically screened samples indicates an Early Kimmeridgian age of the studied deposits, which is in accordance with ostracod biostratigraphic data. An increasing trend in 87Sr/86Sr with stratigraphic height fits well with the global strontium-isotope curve. Besides, similar 87Sr/86Sr ratios derived from different organisms from a single stratigraphic level highlight the suitability of the shells for strontium-isotope stratigraphy. Despite the shallow-marine character of

  15. Determining the geographical origin of Chinese cabbages using multielement composition and strontium isotope ratio analyses

    NASA Astrophysics Data System (ADS)

    BONG, Y.; Shin, W.; Gautam, M. K.; Jeong, Y.; Lee, A.; Jang, C.; Lim, Y.; Chung, G.; Lee, K.

    2012-12-01

    Recently, the Korean market has seen many cases of Chinese cabbage (Brassica rapa ssp. pekinensis) that have been imported from China, yet are sold as a Korean product to illegally benefit from the price difference between the two products. This study aims to establish a method of distinguishing the geographical origin of Chinese cabbage. One hundred Chinese cabbage heads from Korea and 60 cabbage heads from China were subjected to multielement composition and strontium isotope ratio (87Sr/86Sr) analyses. The 87Sr/86Sr ratio differed, based on the geological characteristics of their district of production. In addition, the content of many elements differed between cabbages from Korea and China. In particular, the difference in the content of Sr and Ti alone and the combination of Sr, Ca, and Mg allowed us to distinguish relatively well between Korea and China as the country of origin. The present study demonstrates that the chemical and Sr isotopic analyses exactly reflect the geology of the production areas of Chinese cabbage. Also, multivariate statistical analyses of multiple elements were found to be very effective in distinguishing the geographical origin of Chinese cabbages.

  16. Strontium isotopes document greater human mobility at the start of the Balkan Neolithic

    PubMed Central

    Borić, Dušan; Price, T. Douglas

    2013-01-01

    Questions about how farming and the Neolithic way of life spread across Europe have been hotly debated topics in archaeology for decades. For a very long time, two models have dominated the discussion: migrations of farming groups from southwestern Asia versus diffusion of domesticates and new ideas through the existing networks of local forager populations. New strontium isotope data from the Danube Gorges in the north-central Balkans, an area characterized by a rich burial record spanning the Mesolithic–Neolithic transition, show a significant increase in nonlocal individuals from ∼6200 calibrated B.C., with several waves of migrants into this region. These results are further enhanced by dietary evidence based on carbon and nitrogen isotopes and an increasingly high chronological resolution obtained on a large sample of directly dated individuals. This dataset provides robust evidence for a brief period of coexistence between indigenous groups and early farmers before farming communities absorbed the foragers completely in the first half of the sixth millennium B.C. PMID:23401535

  17. Strontium isotopes document greater human mobility at the start of the Balkan Neolithic.

    PubMed

    Borić, Dušan; Price, T Douglas

    2013-02-26

    Questions about how farming and the Neolithic way of life spread across Europe have been hotly debated topics in archaeology for decades. For a very long time, two models have dominated the discussion: migrations of farming groups from southwestern Asia versus diffusion of domesticates and new ideas through the existing networks of local forager populations. New strontium isotope data from the Danube Gorges in the north-central Balkans, an area characterized by a rich burial record spanning the Mesolithic-Neolithic transition, show a significant increase in nonlocal individuals from ∼6200 calibrated B.C., with several waves of migrants into this region. These results are further enhanced by dietary evidence based on carbon and nitrogen isotopes and an increasingly high chronological resolution obtained on a large sample of directly dated individuals. This dataset provides robust evidence for a brief period of coexistence between indigenous groups and early farmers before farming communities absorbed the foragers completely in the first half of the sixth millennium B.C.

  18. Strontium isotope tracking of groundwater-CO2 interactions in Chimayo, New Mexico, and implications for carbon storage in geologic formations

    NASA Astrophysics Data System (ADS)

    Gardiner, J.; Stewart, B. W.; Capo, R.; Hakala, J.

    2009-12-01

    James Gardiner1, Brian Stewart1, Rosemary Capo1, J. Alexandra Hakala2 1Department of Geology and Planetary Sciences, University of Pittsburgh 2National Energy Technology Laboratory, Pittsburgh, PA The storage of carbon dioxide in geologic formations requires sensitive monitors of the geochemical and mineralogical interactions of storage units, their formation waters, and associated aquifers potentially affected by subsurface CO2. High CO2 subsurface environments can serve as natural analogues for conditions following CO2 injection and provide sites to develop and optimize geochemical tools that can characterize subsurface reactions and identify and track brine and groundwater interactions. Wells in Chimayó, NM tap groundwater from the Tesuque sandstone aquifer, which is crosscut by faults that act as conduits for naturally occurring, deeply sourced CO2. This provides an opportunity for geochemical and isotopic characterization of groundwaters potentially influenced by interaction with CO2. Well waters in the region have 87Sr/86Sr ratios ranging from 0.7176 for CO2-charged brackish water to 0.7098 for a low-TDS groundwater, making the Sr isotope system a potentially sensitive tracer for groundwater-rock interactions. Preliminary strontium isotopic and geochemical data lead to the following observations: (1) Strontium isotope ratios and Sr concentrations in groundwaters sampled within the basin suggest a complex mixing between deep- and shallow-sourced waters, possibly combined with reactions of aquifer carbonate cement or local limestone. (2) Adjacent wells with identical 87Sr/86Sr but significantly different CO2 and alkaline earth concentrations imply CO2 migration from depth into a shallow aquifer, followed by dissolution of carbonate cement. (3) Sr isotope mixing models, when used in conjunction with other geochemical data, can be a strong indicator of decoupling between CO2 and its carrier fluid. Conservative isotope tracers such as 87Sr/86Sr could be an

  19. Mobility during the neolithic and bronze age in northern ireland explored using strontium isotope analysis of cremated human bone.

    PubMed

    Snoeck, Christophe; Pouncett, John; Ramsey, Greer; Meighan, Ian G; Mattielli, Nadine; Goderis, Steven; Lee-Thorp, Julia A; Schulting, Rick J

    2016-07-01

    As many individuals were cremated in Neolithic and Bronze Age Ireland, they have not featured in investigations of individual mobility using strontium isotope analysis. Here, we build on recent experiments demonstrating excellent preservation of biogenic (87) Sr/(86) Sr in calcined bone to explore mobility in prehistoric Northern Ireland. A novel method of strontium isotope analysis is applied to calcined bone alongside measurements on tooth enamel to human remains from five Neolithic and Bronze Age sites in Northern Ireland. We systematically sampled modern vegetation around each site to characterize biologically available strontium, and from this calculated expected values for humans consuming foods taken from within 1, 5, 10 and 20 Km catchments. This provides a more nuanced way of assessing human use of the landscape and mobility than the 'local' vs. 'non-local' dichotomy that is often employed. The results of this study 1) provide further support for the reliability of strontium isotope analysis on calcined bone, and 2) demonstrate that it is possible to identify isotopic differences between individuals buried at the same site, with some consuming food grown locally (within 1-5 Km) while others clearly consumed food from up to 50 Km away from their burial place. Hints of patterning emerge in spite of small sample numbers. At Ballynahatty, for instance, those represented by unburnt remains appear to have consumed food growing locally, while those represented by cremated remains did not. Furthermore, it appears that some individuals from Ballynahatty, Annaghmare and Clontygora either moved in the last few years of their life or their cremated remains were brought to the site. These results offer new insights into the choice behind coterminous cremation and inhumation rites in the Neolithic. Am J Phys Anthropol 160:397-413, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Stratigraphic correlation of Pleistocene California borderland marine carbonate using strontium isotopes

    SciTech Connect

    Capo, R.C. ); Depaolo, D.J. )

    1990-05-01

    High-precision measurements on carbonate sediments have refined the history of the {sup 87}Sr/{sup 86}Sr ratio in Pleistocene seawater and allowed them to construct a standard {sup 87}Sr/{sup 86}Sr vs. age curve, which the authors have applied to stratigraphic correlations in the California Borderland basins. Foraminifera-nannofossil ooze samples from DSDP (Deep Sea Drilling Project) Site 590 in the Tasman Sea (31{degree}S) were analyzed for {sup 87}Sr/{sup 86}Sr to determine the Sr isotopic ratio of ocean water over the past 2.5 m.y. Modeling suggests that changes in river input associated with large variations in global chemical weathering rates are responsible for the observed variations in the {sup 87}Sr/{sup 86}Sr record during the Pliocene-Pleistocene. From 2.4 m.y. to 0.3 m.y., the {sup 87}Sr/{sup 86}Sr ratio of seawater increased rapidly by 14 {times} 10{sup {minus}5}, which makes this period ideal for high-resolution correlations using the Sr isotope method. Based on their standard seawater curve, strontium isotope analyses of macrofossils and foraminifera from carbonate sections from the Santa Barbara-Ventura and Los Angeles basins indicate that the Bathhouse Beach section of the Santa Barbara Formation was deposited between 0.9 and 0.4 m.y. ago, and in part is syndepositional with western portions of the nearly Pliocene-Middle Pleistocene Pico Formation of the Ventura basin, and with the lithologically similar Lomita Marl of the San Pedro Formation at Palos Verdes.

  1. Strontium isotopic signatures of oil-field waters: Applications for reservoir characterization

    USGS Publications Warehouse

    Barnaby, R.J.; Oetting, G.C.; Gao, G.

    2004-01-01

    The 87Sr/86Sr compositions of formation waters that were collected from 71 wells producing from a Pennsylvanian carbonate reservoir in New Mexico display a well-defined distribution, with radiogenic waters (up to 0.710129) at the updip western part of the reservoir, grading downdip to less radiogenic waters (as low as 0.708903 to the east. Salinity (2800-50,000 mg/L) displays a parallel trend; saline waters to the west pass downdip to brackish waters. Elemental and isotopic data indicate that the waters originated as meteoric precipitation and acquired their salinity and radiogenic 87Sr through dissolution of Upper Permian evaporites. These meteoric-derived waters descended, perhaps along deeply penetrating faults, driven by gravity and density, to depths of more than 7000 ft (2100 m). The 87 Sr/86Sr and salinity trends record influx of these waters along the western field margin and downdip flow across the field, consistent with the strong water drive, potentiometric gradient, and tilted gas-oil-water contacts. The formation water 87Sr/86Sr composition can be useful to evaluate subsurface flow and reservoir behavior, especially in immature fields with scarce pressure and production data. In mature reservoirs, Sr Sr isotopes can be used to differentiate original formation water from injected water for waterflood surveillance. Strontium isotopes thus provide a valuable tool for both static and dynamic reservoir characterization in conjunction with conventional studies using seismic, log, core, engineering, and production data. Copyright ??2004. The American Association of Petroleum Geologist. All rights reserved.

  2. Study on strontium isotope abundance-ratio measurements by using a 13-MeV proton beam

    NASA Astrophysics Data System (ADS)

    Jeong, Cheol-Ki; Jang, Han; Lee, Goung-Jin

    2016-09-01

    The Rb-Sr dating method is used in dating Paleozoic and Precambrian rocks. This method measures the 87Rb and the 87Sr concentrations by using thermal ionization mass spectrometry (TIMS) [J. Hefne et al., Inter. J. Phys. Sci. 3(1), 28 (2008)]. In addition, it calculates the initial 87Sr/86Sr ratio to increase the reliability of Rb-Sr dating. In this study, the 87Sr/86Sr ratio was measured by using a 13-MeV proton accelerator. Proton kinetic energies are in the range of tens of megaelectronvolts, and protons have large absorption cross-sections for ( p, n) reactions with most substances. After absorbing a proton with such a high kinetic energy, an element is converted into a nuclide with its atomic number increased by one via nuclear transmutation. These nuclides usually have short half-lives and return to the original state through radioactive decay. When a strontium sample is irradiated with protons, nuclear transmutation occurs; thus, the strontium isotope present in the sample changes to a yttrium isotope, which is an activated radioisotope. Based on this, the 87Sr/86Sr ratio was calculated by analyzing the gamma-rays emitted by each yttrium isotope. The KIRAMS-13 cyclotron at the Cyclotron Center of Chosun University, where 13-MeV protons can be extracted, was utilized in our experiment. The 87Sr/86Sr isotope ratio was computed for samples irradiated with these protons, and the result was similar to the isotope ratio for the Standard Reference Material, i.e., 98.2 ± 3.4%. As part of the analysis, proton activation analyses were performed using 13-MeV protons, and the experimental results of this research suggest a possible approach for measuring the strontium-isotope abundance ratio of samples.

  3. A strontium isotope and trace element profile through the Partridge River Troctolite, Duluth complex, Minnesota

    NASA Astrophysics Data System (ADS)

    Grant, Norman K.; Molling, Philip A.

    1981-10-01

    Initial 87Sr/86Sr ratios down a 2,315 foot-long core (DDH-295) through the Partridge River Troctolite are lower in the depth range 710-1,410 feet (0.70443±22) than in the underlying and overlying rocks (0.70500±18). These initial ratio variations define three zones (I, II, and III) thought to be three intrusive units within the troctolite. The best estimate of the Rb-Sr age of the troctolite is 1,050±105 m.y. The olivine compositions and the abundances of the incompatible trace elements Zr, Y, and Rb show identical variations down the core, with downward repetitions of olivine iron-enrichment and incompatible trace element enrichments. Discontinuities in the olivine compositions and incompatible trace element abundances match the initial 87Sr/86Sr ratio discontinuities in the core. The strontium isotope data imply that involatile components of the Proterozoic Virginia Formation and other Archaean rocks were not significantly assimilated by the troctolites, for only three out of the twenty-three initial 87Sr/86Sr ratios depart from normal magmatic values. These three anomalous ratios are not systematically related to the Cu-Ni sulphide mineralization and may be the result of secondary calcite in the troctolite. The strontium isotope systematics of the Virginia Formation xenoliths and underlying hornfelses are highly disturbed as a result of Rb loss. The apparently inverted fractionation sequences in the troctolites are interpreted in terms of downward increases in intercumulus liquid in repeated magma batches and controlled by plagioclase flotation. The amount of intercumulus liquid is estimated to range from 7 to 61 weight per cent. The Cu-Ni sulphides are concentrated in the lower 250 feet of zone I (immediately above the Virginia Formation) and through 400 feet of core across the contact between zones I and II, more than 750 feet above the base. Because the sulphide-bearing troctolites are not systematically related to disturbances in the magmatic initial 87Sr

  4. Using Strontium Isotopes in Arid Agricultural Soils to Determine a Sink or Source of CO2

    NASA Astrophysics Data System (ADS)

    Ortiz, A. C.; Jin, L.

    2014-12-01

    Arid and semi-arid regions of the world are predicted to continue to expand through land degradation and prolonged drought events. Agricultural practices in these drylands degrade soils through elevated salinity, sodicity and alkalinity. Indeed, flood irrigation loads salts onto the soils including carbonate minerals in the form of calcite. Alfalfa and Pecan are salt tolerant and commonly grown in the arid El Paso region, but need irrigation using Rio Grande water with little to no contribution from local ground waters. We hypothesize that the irrigation is loading extra Ca and bicarbonate to soils and anthropogenically enhancing the precipitation of carbonates. We intend to monitor soil CO2 efflux after irrigation, characterize soil minerals, and combine them to isotopic data of soil, irrigation, and drainage waters to link the sources of Ca and C, kinetics of calcite precipitation, to irrigation events. This will include strontium isotopic analysis to determine the source of calcium in the agricultural fields, U-disequilibrium isotopes to estimate the carbonate ages, and CO2 efflux to monitor atmosphere-soil exchange. Carbon dioxide emissions are expected to change during flood irrigation when soils are saturated. After irrigation events, evaporative effects increase Ca and dissolved inorganic carbon concentration in soil waters leading to precipitation of calcite and thus elevated CO2efflux. Preliminary measurements in the pecan field show a marginally significant difference in CO2 fluxes before and after irrigation (p=0.07, t-test). Carbon dioxide emissions are lower during moist conditions (0.6 g m-2hr-1 CO2) than those in dry conditions (1.0 g m-2hr-1 CO2). Future C isotope data are needed to identify the source of extra CO2, biogenic or calcite-precipitation related. A water leachable extraction of alfalfa soils shows 87Sr/86Sr ratios ranged from 0.7101 to 0.7103, indicating Rio Grande river as a dominant calcium source. Further Sr isotopic analysis of

  5. Strontium Isotopic Variations in the Koolau Volcanic Series, Oahu, Hawaii: Results from KSDP Drill Core

    NASA Astrophysics Data System (ADS)

    Smith, M. M.; Depaolo, D. J.

    2005-12-01

    Surface samples of the Koolau tholeiite series, from the eastern side of the island of Oahu, Hawaii, have long been noted for their unusually high 87Sr/86Sr ratios (up to 0.7042) and other extreme geochemical parameters, as compared to both earlier and later Oahu lavas, values from other Hawaiian islands, and lavas from the Waianae volcano on west Oahu. It has been assumed that the geochemistry of the surface samples of Koolau applied to most of the volcano and that the extreme features were a relatively long-lived characteristic of the Hawaiian mantle plume at the time that the Koolau lavas were being erupted about 3 million years ago. The Koolau Scientific Drilling Project, which returned nearly continuous core from depths of 350 to 670 meters below sea level, provided an opportunity to probe deeper into the Koolau edifice (Haskins and Garcia, CMP, 147, 2004). We present new Sr isotope data on thirty whole rock samples from KSDP, which complement other isotopic data that have been reported recently (Salters and Blichert-Toft, submitted). The KSDP samples have variable, but generally significant, amounts of post-eruption weathering and hence the samples were strongly acid-leached before TIMS isotopic analysis in order to remove any seawater-derived strontium. The 87Sr/86Sr values in the core samples vary from values near 0.7040 at the top of the core to 0.7035 near the bottom. There is a general trend of increasing 87Sr/86Sr upsection as well as oscillations with peak-to-peak amplitude of 0.0003. The Sr isotope ratios correlate reasonably well with Nd and Hf isotope ratios. The data show that the Koolau surface samples are not representative of the volcano as a whole, and that the extreme geochemistry of the surface samples may represent only a minor component of the Hawaiian plume. The normal trend of Sr isotope ratios in the waning stages of shield building is from high values to low (as in Mauna Kea, Kohala, East Molokai and Haleakala). A trend toward higher

  6. Mapping and defining sources of variability in bioavailable strontium isotope ratios in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Hartman, Gideon; Richards, Mike

    2014-02-01

    The relative contributions of bedrock and atmospheric sources to bioavailable strontium (Sr) pools in local soils was studied in Northern Israel and the Golan regions through intensive systematic sampling of modern plants and invertebrates, to produce a map of modern bioavailable strontium isotope ratios (87Sr/86Sr) for regional reconstructions of human and animal mobility patterns. The study investigates sources of variability in bioavailable 87Sr/86Sr ratios, in particular the intra-and inter-site range of variation in plant 87Sr/86Sr ratios, the range of 87Sr/86Sr ratios of plants growing on marine sedimentary versus volcanic geologies, the differences between ligneous and non-ligneous plants with varying growth and water utilization strategies, and the relative contribution of atmospheric Sr sources from different soil and vegetation types and climatic zones. Results indicate predictable variation in 87Sr/86Sr ratios. Inter- and intra-site differences in bioavailable 87Sr/86Sr ratios average of 0.00025, while the range of 87Sr/86Sr ratios measured regionally in plants and invertebrates is 0.7090 in Pleistocene calcareous sandstone and 0.7074 in mid-Pleistocene volcanic pyroclast. The 87Sr/86Sr ratios measured in plants growing on volcanic bedrock show time dependent increases in atmospheric deposition relative to bedrock weathering. The 87Sr/86Sr ratios measured in plants growing on renzina soils depends on precipitation. The spacing between bedrock 87Sr/86Sr ratios and plants is highest in wet conditions and decreases in dry conditions. The 87Sr/86Sr ratios measured in plants growing on terra rossa soils is relatively constant (0.7085) regardless of precipitation. Ligneous plants are typically closer to bedrock 87Sr/86Sr ratios than non-ligneous plants. Since the bioavailable 87Sr/86Sr ratios currently measured in the region reflect a mix of both exogenous and endogenous sources, changes in the relative contribution of exogenous sources can cause variation

  7. Boron and strontium isotope compositions of groundwater from the La Paz arid coastal aquifer, Baja California Sur, Mexico

    NASA Astrophysics Data System (ADS)

    Mahlknecht, Jürgen; Rosner, Martin; Meixner, Anette

    2016-04-01

    In groundwater studies boron and strontium isotopic compositions can be used to identify natural and anthropogenic sources as well as processes related to groundwater recharge, flow and mixing. The La Paz arid costal aquifer in Baja California Sur, Mexico, is the most important source of drinking and irrigation water for La Paz area and suffers from anthropogenic contamination and intensive exploitation of the aquifer causing seawater intrusion and general groundwater abatement. The relatively un-radiogenic 87Sr/86Sr isotope ratios of the La Paz groundwater range in a narrow field between 0.7054 and 0.7062. In contrast to strontium the boron isotope composition displays a large variability between +27 and +55 permil d11B. The relatively low 87Sr/86Sr ratios of the La Paz groundwater highlight a significant contribution of strontium derived from local terrestrial sediments and igneous rocks with known 87Sr/86Sr ratios between 0.705 and 0.7035. The large variability of d11B values indicate that multiple sources and processes determine the boron isotope composition of La Paz groundwater. Rainwater (high d11B), seawater (~+40 permil) due to seawater intrusions, wastewater (low to medium d11B) and boron derived from the local geology (low to medium d11B) explain most of the observed groundwater d11B variability. However, d11B values higher than modern seawater point to significant boron isotope fractionation by preferential absorption of 10B onto clay minerals during the evolution of some groundwater samples. Due to low boron concentrations in rainwater a significant contribution of 11B-rich rainwater (>+40 permil) on the La Paz groundwater is unlikely.

  8. Determination of plutonium isotopes ((238,239,240)Pu) and strontium ((90)Sr) in seafood using alpha spectrometry and liquid scintillation spectrometry.

    PubMed

    Shin, Choonshik; Choi, Hoon; Kwon, Hye-Min; Jo, Hye-Jin; Kim, Hye-Jeong; Yoon, Hae-Jung; Kim, Dong-Sul; Kang, Gil-Jin

    2017-10-01

    The present study was carried out to survey the levels of plutonium isotopes ((238)(,)(239)(,)(240)Pu) and strontium ((90)Sr) in domestic seafood in Korea. In current, regulatory authorities have analyzed radionuclides, such as (134)Cs, (137)Cs and (131)I, in domestic and imported food. However, people are concerned about contamination of other radionuclides, such as plutonium and strontium, in food. Furthermore, people who live in Korea have much concern about safety of seafood. Accordingly, in this study, we have investigated the activity concentrations of plutonium and strontium in seafood. For the analysis of plutonium isotopes and strontium, a rapid and reliable method developed from previous study was used. Applicability of the test method was verified by examining recovery, minimum detectable activity (MDA), analytical time, etc. Total 40 seafood samples were analyzed in 2014-2015. As a result, plutonium isotopes ((238)(,)(239)(,)(240)Pu) and strontium ((90)Sr) were not detected or below detection limits in seafood. The detection limits of plutonium isotopes and strontium-90 were 0.01 and 1 Bq/kg, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Strontium concentrations and isotope ratios in enamel of healthy and carious teeth in southern Shaanxi, China.

    PubMed

    Li, Zixia; He, Maoyong; Peng, Bin; Jin, Zhangdong

    2013-09-15

    As the trace element strontium (Sr) plays a significant role in dental health, it is important to determine the Sr concentration and isotope composition ((87)Sr/(86)Sr) of teeth and whether these values are related to caries formation, age and sex. A total of 160 permanent teeth were collected from 7- to 79-year-old people from the southern Shaanxi area of China, including 100 healthy teeth and 60 carious teeth (men and women each accounted for half of the samples). The concentration and isotope composition of Sr elements in the dental enamel of the teeth were measured using inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry (TIMS). A significantly lower Sr concentration was found in the enamel of the carious teeth than in that of the healthy teeth for individuals of varying ages and sex. The Sr concentration in human carious teeth ranged between 79.70 µg/g and 85.80 µg/g; while the Sr concentration in healthy teeth ranged between 128 µg/g and 156.77 µg/g. Our results also demonstrated that the (87)Sr/(86)Sr ratio did not appear to be affected by the caries formation, age or sex. The (87)Sr/(86)Sr ratio in the enamel of the healthy and carious teeth of individuals of varying ages and genders ranged between 0.710935 and 0.711037, which falls into the range of (87)Sr/(86)Sr ratios found in the local, naturally occurring water, soils and rocks. Sr plays a significant role in dental health, and there is a negative correlation between Sr and the occurrence of dental caries. The (87)Sr/(86)Sr ratio of teeth reflects the (87)Sr/(86)Sr ratio of the associated environment, and there is no significant relationship with the frequency of dental caries, age or sex. Copyright © 2013 John Wiley & Sons, Ltd.

  10. Handbook of stable strontium

    SciTech Connect

    Skoryna, S.C.

    1981-01-01

    This book presents information on the following topics: chemistry of strontium; biogeochemistry of strontium; uptake of stable strontium by plants and effects on plant growth; divalent cation-dependent deposits in paramecium; effects of strontium ion on the hydrolysis of ATP; stronium ions and membranes - screening versus binding at charged surfaces; mitochondrial granules in the liver of rats kept on stable strontium supplementation; divalent cations and regulation of cyclic nucleotides in nervous systems; strontium as the substitute for calcium in the excitation-contraction coupling of crayfish muscle fibers; hemodynamic effects of strontium in the dog; some mechanical characteristics of strontium-mediated contractions in heart muscle; effects of calcium, magnesium, and strontium on drug-receptor interactions; strontium and histamine secretion; and effects of strontium in human dental enamel.

  11. Strontium Concentrations in Corrosion Products from Residential Drinking Water Distribution Systems

    DTIC Science & Technology

    2013-04-22

    incorporation of cobalt and/or strontium into pipe deposits within a distribution system could result in mobilization of these metals into Figure 4...2007, 41 (2), 387−96. (9) Toxicological Profile for Strontium; Agency for Toxic Substances and Disease Registry: Atlanta, GA, 2004. (10) US EPA...calcium (Ca2+). Strontium readily substitutes for Ca2+ in the metal site (M1) of minerals and in the structure of bone.1 The most common Sr2

  12. Elemental geochemistry and strontium-isotope stratigraphy of Cenomanian to Santonian neritic carbonates in the Zagros Basin, Iran

    NASA Astrophysics Data System (ADS)

    Navidtalab, Amin; Rahimpour-Bonab, Hossain; Huck, Stefan; Heimhofer, Ulrich

    2016-12-01

    A Neo-Tethyan upper Cenomanian-Santonian neritic carbonate ramp succession (Sarvak and Ilam formations), drilled in the Zagros Basin in southwest Iran, was investigated via detailed sedimentology, microfacies analysis, elemental geochemistry and Sr-isotope stratigraphy (SIS). The succession contains two exposure surfaces, which are known as the CT-ES and mT-ES (Cenomanian-Turonian and middle Turonian, respectively), and associated prominent negative carbon-isotope excursions that represent important regional stratigraphic marker horizons. Precise knowledge about the onset of platform exposure and the duration of the exposure-related hiatus, however, is currently lacking due to a rather low-resolved shallow-water biostratigraphic framework and a bulk carbonate carbon-isotope pattern that clearly differs from global Late Cretaceous reference curves. Therefore, the existing bio-chemostratigraphic framework was complemented by bulk carbonate strontium-isotope stratigraphy (SIS). As bulk carbonate material is in particular prone to diagenetic alteration, a careful selection of least altered samples has been carried out by means of elemental geochemistry and petrography. In contrast to what could be expected, the meteoric alteration of limestones beneath both exposure surfaces is not clearly expressed by increasing iron and manganese and coeval decreasing strontium contents. On the contrary, the impact of meteoric diagenesis is well illustrated via pronounced increases in Rb concentrations and concomitant prominent positive shifts to radiogenic strontium-isotope values, an observation that clearly reflects the decay of continentally derived 87Rb into 87Sr. Rubidium corrected strontium-isotope values place the CT-ES around the Cenomanian-Turonian boundary and point to an exposure duration of less than 0.4 Myr. This rather short-term CT-ES related hiatus is supported by petrographic evidence, which indicates a youth karstification stage of strata beneath the CT

  13. Human mobility on the Brazilian coast: an analysis of strontium isotopes in archaeological human remains from Forte Marechal Luz Sambaqui.

    PubMed

    Bastos, Murilo Q R; Souza, Sheila M F Mendonça de; Santos, Roberto V; Lima, Bárbara A F; Santos, Ricardo V; Rodrigues-Carvalho, Claudia

    2011-06-01

    This study investigated strontium isotopes in the dental enamel of 32 human skeletons from Forte Marechal Luz sambaqui (shellmound), Santa Catarina, Brazil, aiming at identifying local and non-local individuals. The archeological site presents pot sherds in the uppermost archeological layers. Dental enamel was also examined from specimens of terrestrial fauna ((87)Sr/(86)Sr = 0.71046 to 0.71273) and marine fauna ((87)Sr/(86)Sr = 0.70917). The (87)Sr/(86)Sr isotope ratio for individuals classified as locals ranged from 0. 70905 to 0. 71064 and was closer to the isotope ratio of the seawater than to the ratio of the terrestrial fauna, indicating a strong influence of marine strontium on the inhabitants of this sambaqui. The results indicate the existence of three non-local individuals ((87)Sr/(86)Sr = 0.70761 to 0.70835), buried in both the level without pottery and the layer with pottery, possibly originated from the Santa Catarina Plateau, close to the municipality of Lages, or from the Curitiba Plateau. The occurrence of a slight difference between the isotope ratios of local individuals buried in the archeological layer without pottery, when compared to those in the layer with pottery, suggests a possible change in dietary patterns between these two moments in the site's occupation.

  14. Using stable isotopes of water and strontium to investigate the hydrology of a natural and a constructed wetland

    USGS Publications Warehouse

    Hunt, R.J.; Bullen, T.D.; Krabbenhoft, D.P.; Kendall, C.

    1998-01-01

    Wetlands cannot exist without water, but wetland hydrology is difficult to characterize. As a result, compensatory wetland mitigation often only assumes the proper hydrology has been created. In this study, water sources and mass transfer processes in a natural and constructed wetland complex were investigated using isotopes of water and strontium. Water isotope profiles in the saturated zone revealed that the natural wetland and one site in the constructed wetland were primarily fed by ground water; profiles in another constructed wetland site showed recent rain was the predominant source of water in the root zone. Water isotopes in the capillary fringe indicated that the residence time for rain is less in the natural wetland than in the constructed wetland, thus transpiration (an important water sink) was greater in the natural wetland. Strontium isotopes showed a systematic difference between the natural and constructed wetlands that we attribute to the presence or absence of peat. In the peat-rich natural wetland, ??87Sr in the pore water increased along the flowline due to preferential weathering of minerals containing radiogenic Sr in response to elevated Fe concentrations in the water. In the constructed wetland, where peat thickness was thin and Fe concentrations in water were negligible, ??87Sr did not increase along the flowline. The source of the peat (on-site or off-site derived) applied in the constructed wetland controlled the ??87Sr at the top of the profile, but the effects were restricted by strong cation exchange in the underlying fluvial sediments. Based on the results of this study, neither constructed wetland site duplicated the water source and weathering environment of the adjoining natural wetland. Moreover, stable isotopes were shown to be effective tools for investigating wetlands and gaining insight not easily obtained using non-isotopic techniques. These tools have potential widespread application to wetlands that have distinct isotopic

  15. Using stable isotopes of water and strontium to investigate the hydrology of a natural and a constructed wetland

    SciTech Connect

    Hunt, R.J.; Krabbenhoft, D.P.; Bullen, T.D.; Kendall, C.

    1998-05-01

    Wetlands cannot exist without water, but wetland hydrology is difficult to characterize. In this study, water sources and mass transfer processes in a natural and constructed wetland complex were investigated using isotopes of water and strontium. Water isotope profiles in the saturated zone revealed that the natural wetland and one site in the constructed wetland were primarily fed by ground water; profiles in another constructed wetland site showed recent rain was the predominant source of water in the root zone. Water isotopes in the capillary fringe indicated that the residence time for rain is less in the natural wetland than in the constructed wetland, thus transpiration (an important water sink) was greater in the natural wetland. Strontium isotopes showed a systematic difference between the natural and constructed wetlands that the authors attribute to the presence or absence of peat. In the peat-rich natural wetland, {delta}{sup 87}Sr in the pore water increased along the flowline due to preferential weathering of minerals containing radiogenic Sr in response to elevated Fe concentrations in the water. In the constructed wetland, where peak thickness was thin and Fe concentrations in water were negligible, {delta}{sup 87}Sr did not increase along the flowline. The source of the pea (on-site or off-site derived) applied in the constructed wetland controlled the {delta}{sup 87}Sr at the top of the profile, but the effects were restricted by strong cation exchange in the underlying fluvial sediments. Based on the results of this study, neither constructed wetland site duplicated the water source and weathering environment of the adjoining natural wetland. Moreover, stable isotopes were shown to be effective tools for investigating wetlands and gaining insight not easily obtained using non-isotopic techniques. These tools have potential widespread application to wetlands that have distinct isotopic endmember sources.

  16. A Strontium Isotope Reconnaissance of a Marine Terrace Chronosequence in Central California, USA.

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, J. A.; Bullen, T. D.; Vivit, D. V.; White, A. F.

    2002-12-01

    Long-term sampling locations have been established on a chronosequence of marine terraces north of Santa Cruz, CA. Investigation of these sites will allow a multi-disciplinary assessment of mineral weathering and soil formation processes. The five surfaces comprising the chronosequence (terraces 1-5) have been dated at 65ka, 92ka, 137ka, 139ka, and 226ka, respectively, by Perg et al, 2001 using cosmogenic radionuclides (CRN). Soil horizons have developed in the sediments covering the terraces, derived locally from the Miocene Santa Margarita sandstone, Santa Cruz mudstone, and the Cretaceous Ben Lomond Granodiorite. The terrace sites have been sampled and instrumented with suction water samplers and precipitation collectors. Bi-monthly collection of soil waters, surface waters, precipitation, and vegetation are on going. This component of the study will use Sr isotopes (87Sr/86Sr) to understand sources, cycling, and behavior of strontium and associated base cations. 87Sr/86Sr measurements have been made on a variety of materials from terrace sites 1-5, including precipitation, soil waters, ground and surface waters, vegetation, ammonium-acetate extractable soil Sr, and soil digests. Additionally, 87Sr/86Sr measurements have been made on local bedrock and beach sands. The measured values of 87Sr/86Sr in the samples range from 0.706 in deep soil water and soil exchange extracts to 0.710 in surface waters and soil digests. Isotopic values for eight precipitation samples at the terraces average 0.7091, reflecting the marine influence. Depth profiles of ammonium-acetate exchangeable soil Sr and soil waters from equivalent depths yield similar values and trends in 87Sr/86Sr (from 0.709 at the top toward 0.706 at 6 meter depth), suggesting that equilibrium is established between exchange sites and associated waters. Decreasing 87Sr/86Sr values with depth suggest a dominant influence of precipitation derived Sr on the cation exchange pool at the surface and emergence of a

  17. Strontium alteration in the Troodos ophiolite: implications for fluid fluxes and geochemical transport in mid-ocean ridge hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Bickle, Mike J.; Teagle, Damon A. H.

    1992-09-01

    New and published strontium isotope analyses from the Troodos ophiolite constrain fluid-solid exchange processes, and the magnitude and circulation paths of the hydrothermal fluids. The 87Sr/ 86Sr profile reflects alteration in the recharge zone of an evolving hydrothermal system. Fluid-rock strontium isotope exchange in the upper ˜ 1.5 km of extrusive lavas was kinetically limited and seawater-derived fluids emitted from the base of this zone were buffered to 87Sr/ 86Sr ratios between ˜ 0.7047 and 0.7059. In contrast, over the next ˜ 1 km depth interval of sheeted dykes and the uppermost plutonics, 87Sr/ 86Sr values cluster about0.7054 ± 7 (2σ) and fluid flow is inferred to have been pervasive with near-equilibrium fluid-rock exchange. Quartz-chlorite and epidosite zones, the probable pathways of the concentrated, high-temperature upwelling fluids, have identical 87Sr/ 86Sr ratios to adjacent diabase dykes. On Troodos a time-integrated fluid flux in excess of2.9 × 10 7 kg m -2 is required to transport the strontium isotope composition of ˜ 0.7054, set in the kinetically controlled exchange zone, through the ˜ 1 km of sheeted dykes and into the zones of concentrated upwelling. The uniformity of the 87Sr/ 86Sr ratios in the diabase sheeted dykes and high-temperature epidosite and quartz-chlorite rocks indicate that the strontium isotopic alteration took place during the high temperature phase of hydrothermal circulation. The inferred minimum time-integrated fluid flux of2.9 × 10 7 kg m -2 substantially exceeds that of˜ 5 × 10 6 kg m -2 inferred from thermal models of high temperature circulation, but is comparable with estimates of the hydrothermal flux from oceanic budgets of 3He, Mg and 87Sr. The high flux estimate for Troodos is consistent with the ophiolite venting fluids, with 87Sr/ 86Sr elevated significantly above rock values, which contrasts with the near-MORB 87Sr/ 86Sr ratios of fluids from active high-temperature vents at mid-ocean ridges and

  18. Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

    SciTech Connect

    Brubaker, Tonya M; Stewart, Brian W; Capo, Rosemary C; Schroeder, Karl T; Chapman, Elizabeth C; Spivak-Birndorf, Lev J; Vesper, Dorothy J; Cardone, Carol R; Rohar, Paul C

    2013-05-01

    The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope results from both column and batch leaching experiments show a marked increase in {sup 87}Sr/{sup 86}Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface and ground waters.

  19. Strontium isotopic, chemical, and sedimentological evidence for the evolution of Lake Lisan and the Dead Sea

    NASA Astrophysics Data System (ADS)

    Stein, M.; Starinsky, A.; Katz, A.; Goldstein, S. L.; Machlus, M.; Schramm, A.

    1997-09-01

    Precise strontium isotope ratios, combined with chemical analyses and sedimentological information, are used to monitor the water sources and the evolution of the Dead Sea and its late Pleistocene precursor, Lake Lisan (70-18 kyr B.P.). The materials analyzed include bulk aragonite, water-leached soluble salts, and residual aragonite and gypsum from the Lisan Formation in the Perazim Valley (near the SW shore of the Dead Sea). The residual aragonite and the associated soluble salts display systematic fluctuations in 17Sr/86Sr ratios between 0.70803 and 0.70806 and from 0.70805 to 0.70807, respectively. In individual soluble salt-residual aragonite pairs, the soluble salt displays a higher 87Sr/86Sr ratio. Gypsum samples yield 17Sr/86Sr ratios similar to the soluble salts from adjacent layers in the section. This shows that, in individual samples, the source of Sr in aragonite was distinct from that in soluble salts and the gypsum. The sterility of the Lisan sediments, their strictly nonbioturbated fine lamination, and their high content of chloride salts indicate that Lake Lisan was a saline, or even hypersaline water body. In the absence of alternative sources of HCO 3- and S0 42- the abundance of primary aragonite and gypsum in the Lisan column reflects an import of very large volumes of freshwater into the otherwise saline lake, resulting in a density stratification of this water body. The history of the upper water layer and that of the lower brine is reflected in the chemical and strontium isotope composition of the aragonite and in that of the associated soluble salts and in the gypsum samples, respectively. Whereas the bicarbonate and much of the Ca 2+ required for aragonite crystallization were supplied by the freshwater, the complementary Ca 2+ (and Sr 2+) were added by the lower brine. The upper water layer of Lake Lisan acted as a SO 42- capacitor during the lake's rise periods. It was removed therefrom, as prominent gypsum beds, upon climatic

  20. Oxygen and strontium isotopic studies of basaltic lavas from the Snake River plain, Idaho

    USGS Publications Warehouse

    Leeman, William P.; Whelan, Joseph F.

    1983-01-01

    The Snake Creek-Williams Canyon pluton of the southern Snake Range crops out over an area of about 30 km2, about 60 km southeast of Ely, Nev. This Jurassic intrusion displays large and systematic chemical and mineralogical zonation over a horizontal distance of 5 km. Major-element variations compare closely with Dalyls average andesite-dacite-rhyolite over an SiO2 range of 63 to 76 percent. For various reasons it was originally thought that assimilation played a dominant role in development of the Snake Creek-Williams Canyon pluton. However, based on modeling of more recently obtained trace element and isotopic data, we have concluded that the zonation is the result of in-situ fractional crystallization, with little assimilation at the level of crystallization. This report summarizes data available for each of the mineral species present in the zoned intrusion. Special attention has been paid to trends We present oxygen and strontium isotopic data for olivine tholeiites, evolved (that is, differentiated and (or) contaminated) lavas, rhyolites, and crustal- derived xenoliths from the Snake River Plain. These data show that the olivine tholeiites are fairly uniform in d80 (5.1 to 6.2) and 87Sr/86Sr (0.7056 to 0.7076) and reveal no correlation between these ratios. The tholeiites are considered representative of mantle-derived magmas that have not interacted significantly with crustal material or meteoric water. The evolved lavas display a wider range in d 80 (5.6 to 7.6) and 87Sr/86Sr (0.708 to 0.717) with positive correlations between these ratios in some suites but not in others. Crustal xenoliths have high and variable 8?Sr/86Sr (0.715 to 0.830) and d80 values that vary widely (6.7 to 9.2) and are a few permil greater than d80 values of the Snake River basalts. Thus, isotopic data for the evolved lavas are permissive of small degrees of contamination by crustal rocks similar to the most d80-depleted xenoliths. The d80 enrichments in some evolved lavas also are

  1. Local and foreign males in a late Bronze Age cemetery at Neckarsulm, south-western Germany: strontium isotope investigations.

    PubMed

    Wahl, Joachim; Price, T Douglas

    2013-01-01

    The cemetery of Neckarsulm in southwestern Germany was discovered in 2001 and contained the inhumation graves of 50 individuals in 32 graves. The cemetery was in use for about 50 years during the Late Bronze Age (Urnfield culture, Hallstatt A1 period). The individuals who could confidently be identified were almost exclusively adult males. The majority of the skeletal remains exhibit specialized facets that most likely resulting from horseback riding. Several characteristics make this cemetery very unusual: The inhumations in contrast to normal cremation in this time period, the large number of multiple burials, the uniform sex and age of the deceased. There is no information concerning the cause of death of the individuals from the cemetery. Isotopic analysis was used for diet and mobility investigation. Diet for these individuals was relatively homogeneous and included both terrestrial and freshwater species. Tooth enamel from 37 individuals was analysed for strontium and oxygen isotopes. Almost one-third of the individuals in the sample exhibited non-local strontium isotope ratios and likely came from different areas in southwest Germany.

  2. Strontium isotope quantification of siderite, brine and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau

    SciTech Connect

    Chapman, Elizabeth C.; Capo, Rosemary C.; Stewart, Brian W.; Hedin, Robert S.; Weaver, Theodore J.; Edenborn, Harry M.

    2013-04-01

    Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotope mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.

  3. Investigation of groundwater flow paths through combined inversion of strontium isotope ratios and hydraulic head data. Final report

    SciTech Connect

    Thomas M. Johnson

    1999-12-04

    Strontium (Sr) isotope and other geochemical data were collected for groundwater samples from the Snake River Plain aquifer in the vicinity of the Idaho National Engineering and Environmental Laboratory (INEEL). These geochemical data provide strong evidence for slow and fast groundwater flow zones that had not been previously characterized. The geochemical data were combined with existing hydraulic head data in groundwater flow and transport models. These models enable quantitative extraction of flow information from the data (i.e., inversion of the data). This new approach and the implications for INEEL environmental activities will be reported in two journal articles. One submitted recently and a second in preparation.

  4. Pliocene Transgression in the Western Mediterranean Sea: Strontium Isotopes from Cuevas Del Almanzora (Se Spain)

    NASA Astrophysics Data System (ADS)

    Müller, Daniel W.

    1993-02-01

    The deposition of marine sediments in the deep Mediterranean basins following the Messinian salinity crisis ("Zanclean Deluge") began at 4.9 Ma and continued until normal marine conditions prevailed at 4.6 Ma. The Betic Strait of southeast Spain, the Rif Strait of northern Morocco, and the Strait of Gibraltar have been postulated as possible entry ways for the marine waters into the Mediterranean. Two possible explanations have been offered for the timing of the deposition of marine hemipelagic marls in the Vera Basin (Cuevas del Almanzora section) within the Betic Strait: (1) early Pliocene, representing the "Zanclean Deluge" (Cita et al., 1980), (2) Messinian (˜5.7 Ma), representing the last marine stage before the Messinian salinity crisis (Benson and Rakic-El Bied, 1991; Benson et al., 1991). The strontium isotopic ratio on mixed assemblages of foraminifers from these marine marls was determined in order to assess their ages. The average 87Sr/86Sr (0.709033±24) of the seven measured samples is, compared to the base of the Miocene/Pliocene boundary stratotype at Capo Rossello, Sicily, higher by 38 × 10-6 and yields an age of 4.6±0.5 Ma when compared to the established open ocean Sr seawater curve. The determined age indicates that (1) the first 3.6 m of marine deposits of the Cuevas del Almanzora section sensu Cita et al. (1980) including the passage zone are Pliocene, (2) the earliest marine Pliocene might not be represented at Cuevas del Almanzora indicating that this marginal basin at the edge of the Mediterranean Sea, yet within the former Betic Strait, was filled progressively by a marine transgression originating from the Mediterranean Sea around 4.6 Ma. The absence of lowermost Pliocene sediments could suggest that the Betic Strait did not serve as a conduit for the water masses entering the Mediterranean basins during the early Pliocene; and (3) the presence of an early evolutionary stage of Globorotalia margaritae in the Moroccan Bou Regreg section

  5. Application of strontium isotope measurements to trace sediment sources in an upstream agricultural catchment (Loire River basin, France)

    NASA Astrophysics Data System (ADS)

    Le Gall, Marion; Evrard, Olivier; Thil, François; Foucher, Anthony; Salvador-Blanes, Sébastien; Cerdan, Olivier; Ayrault, Sophie

    2015-04-01

    Soil erosion is recognized as one of the main processes of land degradation in agricultural areas. It accelerates the supply of sediment to the rivers and degrades water quality. To limit those impacts and optimize management programs in such areas, sources of sediment need to be identified and sediment transport to be controlled. Here, we determined the sources of suspended sediment in the Louroux (24 km², French Loire River basin), a small catchment representative of lowland cultivated environments of Northwestern Europe. In this catchment, channels have been reshaped and 220 tile drain outlets have been installed over the last several decades. As a result, soil erosion and sediment fluxes have increased drastically. The variation of 87Sr/86Sr ratios, driven by the weathering of rocks with different ages and chemical composition, may reflect the mixing of different sediment sources. Strontium isotopic ratios (87Sr/86Sr) were therefore determined in potential soil sources, suspended particulate matter (SPM) and a sediment core sampled in the Louroux Pond at the catchment outlet. Soil, SPM and core samples displayed significantly different isotopic signatures. 87Sr/86Sr ratios in soil samples varied from 0.712763 to 0.724631 ± 0.000017 (2σ, n=20). Highest values were observed in silicic parts of the catchment whereas the lower values were identified in a calcareous area close to the Louroux Pond. 87Sr/86Sr ratios in SPM (0.713660 to 0.725749 ± 0.000017, 2σ, n=20) plotted between the soil and sediment core (0.712255 to 0.716415 ± 0.000017, 2σ, n=12), suggesting the presence of particles originating from at least two different lithological sources, i.e. silicic rocks and carbonate material. Variations in 87Sr/86Sr ratios in the outlet core sample were used to reconstruct the sedimentary dynamics in the catchment during the last decades. These results will guide the future implementation of appropriate management practices aiming to reduce erosion in upstream

  6. Using Carbon, Oxygen, Strontium, and Lead Isotopes in Modern Human Teeth for Forensic Investigations: A Critical Overview Based on Data from Bulgaria.

    PubMed

    Kamenov, George D; Curtis, Jason H

    2017-02-23

    Isotopic data obtained from human remains can provide information about an individual's origin, migration, and diet. We evaluate the usefulness of carbon, oxygen, strontium, and lead isotopes for forensic investigations by comparing data from Bulgarian teeth with data from other regions. Geo-referencing based on oxygen or strontium isotopes can be misleading due to overlap with other countries in Europe and other continents. Carbon and lead isotopes, in combination with oxygen and strontium isotopes, provide the most useful information for identification of local vs foreigner status. In particular, high-precision Pb isotopes show a distinct "Bulgarian" range; however, it is possible that individuals from other countries in Eastern Europe and/or central to western Asia could have overlapping isotopic values. Additional high-precision multi-isotope data from modern humans from different regions in the world are required to transition from speculative to more quantitative estimation of a geographical place of origin for unidentified human remains. © 2017 American Academy of Forensic Sciences.

  7. Isotope Specific Remediation Media and Systems - 13614

    SciTech Connect

    Denton, Mark S.; Mertz, Joshua L.; Morita, Keisuke

    2013-07-01

    On March 11, 2011, now two years ago, the magnitude 9.0 Great East Japan earthquake, Tohoku, hit off the Fukushima coast of Japan. While, of course, most of the outcome of this unprecedented natural and manmade disaster was a negative, both in Japan and worldwide, there have been some extremely invaluable lessons learned and new emergency recovery technologies and systems developed. As always, the mother of invention is necessity. Among these developments has been the development and full-scale implementation of proven isotope specific media (ISMs) with the intent of surgically removing specific hazardous isotopes for the purpose of minimizing dose to workers and the environment. The first such ISMs to be deployed at the Fukushima site were those removing cesium (Cs-137) and iodine (I-129). Since deployment on June 17, 2011, along with treated cooling water recycle, some 70% of the curies in the building liquid wastes have been removed by the Kurion system alone. The current levels of cesium are now only 2% of the original levels. Such an unprecedented, 'external cooling system' not only allowed the eventual cold shut down of the reactors in mid-December, 2011, but has allowed workers to concentrate on the cleanup of other areas of the site. Water treatment will continue for quite some time due to continued leakage into the buildings and the eventual goal of cleaning up the reactors and fuel pools themselves. With the cesium removal now in routine operation, other isotopes of concern are likely to become priorities. One such isotope is that of strontium, and yttrium (Sr-90 and Y-90), which is still at original levels causing further dose issues as well as impediments to discharge of the treated waste waters. For over a year now, a new synthetic strontium specific media has been under development and testing both in our licensed facility in Oak Ridge, Tennessee, but also in confirmatory tests by the Japan Atomic Energy Agency (JAEA) in Japan for Tokyo Electric Power

  8. Imbalance in the oceanic strontium budget

    NASA Astrophysics Data System (ADS)

    Davis, Amy C.; Bickle, Mike J.; Teagle, Damon A. H.

    2003-06-01

    Palmer and Edmond [Earth Planet. Sci. Lett. 92 (1989) 11-26] indicated that thermally plausible oceanic hydrothermal inputs of strontium to the oceans are not sufficient to balance the riverine input. It has recently been suggested that off-axis low-temperature hydrothermal circulation may reconcile this discrepancy [e.g. Butterfield et al., Geochim. Cosmochim. Acta 65 (2001) 4141-4153]. Strontium isotope alteration profiles are compiled for sampled in situ ocean and ophiolite crust to calculate a sustainable cumulative hydrothermal flux to the oceanic strontium budget. High-temperature circulation contributes ˜1.8×10 9 mol yr -1 of basaltic strontium to the oceans. Enhanced hydrothermal systems in arc-related spreading environments (10% of the crust) may increase this to ˜2.3×10 9 mol yr -1. It is shown that low-temperature flow cannot supply the remaining flux required to reconcile the oceanic strontium budget (˜8.7×10 9 mol yr -1) because this would require 100% exchange of seawater strontium for basaltic strontium over an 820 m section of MORB-like crust. Currently sampled in situ ocean crust is not altered to this extent. The isotopic alteration intensity of 120 Myr crust sampled in DSDP Holes 417D and 418A indicates that off-axis low-temperature flow may contribute up to ˜8×10 8 mol yr -1 of basaltic strontium (9% of that required). The ocean crust can sustain a total basaltic strontium flux of ˜3.1±0.8×10 9 mol yr -1 ( 87Sr/ 86Sr ˜0.7025) to the oceans. This is consistent with hydrothermal flux estimates, but remains less than a third of the flux required to balance the oceanic strontium budget. The ocean crust cannot support a higher hydrothermal contribution unless the average ocean crust is significantly more altered than current observation.

  9. Strontium isotope geochemistry of groundwater in the central part of the Dakota (Great Plains) aquifer, USA

    USGS Publications Warehouse

    Gosselin, D.C.; Harvey, F.E.; Frost, C.; Stotler, R.; Macfarlane, P.A.

    2004-01-01

    The Dakota aquifer of the central and eastern Great Plains of the United States is an important source of water for municipal supplies, irrigation and industrial use. Although the regional flow system can be characterized generally as east to northeasterly from the Rocky Mountains towards the Missouri River, locally the flow systems are hydrologically complex. This study uses Sr isotopic data from groundwater and leached aquifer samples to document the complex subsystems within the Dakota aquifer in Nebraska and Kansas. The interaction of groundwater with the geologic material through which it flows has created spatial patterns in the isotopic measurements that are related to: long-term water-rock interaction, during which varying degrees of isotopic equilibrium between water and rock has been achieved; and the alteration of NaCl fluids by water-rock interaction. Specifically, Sr isotopic data distinguish brines from Kansas and western Nebraska from those in eastern Nebraska: the former are interpreted to reflect interaction with Permian rocks, whereas the latter record interaction with Pennsylvanian rocks. The Sr isotopic composition of groundwater from other parts of Nebraska and Kansas are a function of the dynamic interaction between groundwater and unlithified sediments (e.g., glacial till and loess), followed by interaction with oxidized and unoxidized sediments within the Dakota Formation. This study illustrates the power of combining Sr chemistry with more conventional geochemical data to obtain a more complete understanding of groundwater flow systems within regional aquifer systems where extensive monitoring networks do not exist. ?? 2003 Elsevier Ltd. All rights reserved.

  10. Origin of epigenetic calcite in coal from Antarctica and Ohio based on isotope compositions of oxygen, carbon and strontium

    USGS Publications Warehouse

    Faure, G.; Botoman, G.

    1984-01-01

    Isotopic compositions of oxygen, carbon and strontium of calcite cleats in coal seams of southern Victoria Land, Antarctica, and Tuscarawas County, Ohio, contain a record of the conditions a the time of their formation. The Antarctic calcites (?? 18O(SMOW) = +9.14 to +11.82%0) were deposited from waters enriched in 16O whose isotopic composition was consistent with that of meteoric precipitation at low temperature and high latitude. The carbon of the calcite cleats (?? 13C(PDB) = -15.6 to -16.9%0) was derived in part from the coal (?? 13C(PDB) = -23.5 to -26.7%0) as carbon dioxide and by oxidation of methane or other hydrocarbon gases. The strontium ( 87Sr 86Sr = 0.71318-0.72392) originated primarily from altered feldspar grains in the sandstones of the Beacon Supergroup. Calcite cleats in the Kittaning No. 6 coal seam of Ohio (?? 18O(SMOW) = +26.04 to +27.79%0) were deposited from waters that had previously exchanged oxygen, possibly with marine carbonate at depth. The carbon (?? 13C(PDB) = 0.9 to +2.4%0) is enriched in 13C even though that cleats were deposited in coal that is highly enriched in 12C and apparently originated from marine carbonates. Strontium in the cleats ( Sr 87 0.71182-0.71260) is not of marine origin but contains varying amounts of radiogenic 87Sr presumably derived from detrital Rb-bearing minerals in the adjacent sedimentary rocks. The results of this study suggest that calcite cleats in coal of southern Victoria Land, Antarctica, were deposited after the start of glaciation in Cenozoic time and that those in Ohio precipitated from formation waters derived from the underlying marine carbonate rocks, probably in the recent geologic past. ?? 1984.

  11. The strontium isotopic composition of basalts from the Gordo and Juan de Fuca Rises, northeastern Pacific Ocean

    USGS Publications Warehouse

    Hedge, C.E.; Peterman, Z.E.

    1970-01-01

    The strontium isotopic compositions have been determined for twelve tholeiitic basalts dredged from the Gordo and Juan de Fuca Rises. Sr87/Sr86 ratios range from 0.7012 to 0.7031 and average 0.7026. These data, combined with other data from the East Pacific Rise indicate that tholeiite basalts being erupted along the active rises, in the Pacific Ocean, contain less radiogenic Sr87 than basalts erupted on the islands. These isotopic differences between the ocean-ridge tholeiite and the more alkali island basalts indicate that variations in Rb/Sr have persisted in the mantle for billions of years. The possible origins and distribution of these heterogeneties are discussed. ?? 1970 Springer-Verlag.

  12. Ancient DNA, Strontium isotopes, and osteological analyses shed light on social and kinship organization of the Later Stone Age

    PubMed Central

    Haak, Wolfgang; Brandt, Guido; de Jong, Hylke N.; Meyer, Christian; Ganslmeier, Robert; Heyd, Volker; Hawkesworth, Chris; Pike, Alistair W. G.; Meller, Harald; Alt, Kurt W.

    2008-01-01

    In 2005 four outstanding multiple burials were discovered near Eulau, Germany. The 4,600-year-old graves contained groups of adults and children buried facing each other. Skeletal and artifactual evidence and the simultaneous interment of the individuals suggest the supposed families fell victim to a violent event. In a multidisciplinary approach, archaeological, anthropological, geochemical (radiogenic isotopes), and molecular genetic (ancient DNA) methods were applied to these unique burials. Using autosomal, mitochondrial, and Y-chromosomal markers, we identified genetic kinship among the individuals. A direct child-parent relationship was detected in one burial, providing the oldest molecular genetic evidence of a nuclear family. Strontium isotope analyses point to different origins for males and children versus females. By this approach, we gain insight into a Late Stone Age society, which appears to have been exogamous and patrilocal, and in which genetic kinship seems to be a focal point of social organization. PMID:19015520

  13. Ancient DNA, Strontium isotopes, and osteological analyses shed light on social and kinship organization of the Later Stone Age.

    PubMed

    Haak, Wolfgang; Brandt, Guido; de Jong, Hylke N; Meyer, Christian; Ganslmeier, Robert; Heyd, Volker; Hawkesworth, Chris; Pike, Alistair W G; Meller, Harald; Alt, Kurt W

    2008-11-25

    In 2005 four outstanding multiple burials were discovered near Eulau, Germany. The 4,600-year-old graves contained groups of adults and children buried facing each other. Skeletal and artifactual evidence and the simultaneous interment of the individuals suggest the supposed families fell victim to a violent event. In a multidisciplinary approach, archaeological, anthropological, geochemical (radiogenic isotopes), and molecular genetic (ancient DNA) methods were applied to these unique burials. Using autosomal, mitochondrial, and Y-chromosomal markers, we identified genetic kinship among the individuals. A direct child-parent relationship was detected in one burial, providing the oldest molecular genetic evidence of a nuclear family. Strontium isotope analyses point to different origins for males and children versus females. By this approach, we gain insight into a Late Stone Age society, which appears to have been exogamous and patrilocal, and in which genetic kinship seems to be a focal point of social organization.

  14. A reconnaissance study of oxygen, hydrogen and strontium isotopes in geochemically diverse lakes, Western Nebraska, USA

    USGS Publications Warehouse

    Gosselin, D.C.; Nabelek, P.E.; Peterman, Z.E.; Sibray, S.

    1997-01-01

    Reconnaissance ??18O,, ??D, and ??87Sr data for fifteen lakes in the Western Lakes Region of the Sand Hills of Nebraska indicate dynamic hydrologic systems. The rather narrow range of ??87Sr from lake water (1.1 to 2.1) and groundwater (0.9 to 1.7) indicates that the groundwater is generally unradiogenic. Groundwater residence times and relatively unradiogenic volcanic ash within the dune sediments control the ??87Sr values. Based on the mutual variations of ??18O and ??D, the lakes can be divided into three groups. In Group 1, both ??18O and ??D values increase from spring to fall. The ??18O and ??D values in Group 2 decreased from spring to fall. Group 3 are ephemeral lakes that went dry some time during 1992. The data and isotopic modeling show that variations in the ratio of evaporation relative to groundwater inflow, local humidity conditions, and the ??(a) has substantial influence on the isotopic composition. In addition, isotopic behavior in ephemeral hakes can be rather unusual because of the changing activities of water and mineral precipitation and redissolution. The annual and interannual isotopic variability of these lakes which is reflected in the paleonvironmental indicators may be the rule rather than the exception in these types of systems.

  15. Implications for post-comminution processes in subglacial suspended sediment using coupled radiogenic strontium and neodymium isotopes

    NASA Astrophysics Data System (ADS)

    Clinger, Anna E.; Aciego, Sarah M.; Stevenson, Emily I.; Arendt, Carli A.; Robbins, Mark J.

    2016-04-01

    Enhanced physical weathering rates in subglacial systems promote high levels of comminution, transport, and deposition of fine-grained sediment within the subglacial drainage network. The impact of shifts in sediment loads from variations in meltwater flux, and their effects on downstream ecosystems, remains poorly quantified and places a fundamental importance on our ability to characterize subglacial depositional environments. Here, for the first time, we assess the seasonal evolution of the subglacial suspended sediment using coupled radiogenic strontium (87Sr/86Sr) and neodymium (143Nd/144Nd) isotopic ratios with elemental ratios and in situ measurements. Weathering rates in fluvial and riverine systems have been traditionally assessed using radiogenic isotopic tracers: 143Nd/144Nd ratios relate to the crustal age whereas 87Sr/86Sr ratios relate to age and preferential mineral dissolution. Thus relative shifts in these ratios will allow us to characterize distinct sediment transport networks. We apply this technique to the Lemon Creek Glacier (LCG), Alaska, USA, and to the Athabasca Glacier (AG), Alberta, CA. At the LCG, the 143Nd/144Nd values range from εNd of - 4.6 (0.9) to - 8.7 (0.2), which suggests a poorly mixed sediment flux. However, the greatest period of variability may correlate with the drainage of a supraglacial lake and suggests caution should be exerted in time-scale 143Nd/144Nd provenance studies that may be affected by climatic disturbances. In contrast, limited variation is observed within the AG 143Nd/144Nd seasonal record. A consistent, direct relation between the Rb/Sr elemental ratio and the 87Sr/86Sr ratio proves interesting as it enables us to unravel incongruent weathering trends in the radiogenic Sr record. Correlation between the 87Sr/86Sr and total discharge suggests that the process is partially controlled by mantling of the bedrock, which can be detected using post-comminution ages. While the subglacial structure may be enabled by

  16. Strontium and oxygen isotopic variations in Mesozoic and Tertiary plutons of central Idaho

    USGS Publications Warehouse

    Fleck, R.J.; Criss, R.E.

    1985-01-01

    Regional variations in initial 87Sr/86Sr ratios (ri) of Mesozoic plutons in central Idaho locate the edge of Precambrian continental crust at the boundary between the late Paleozoic-Mesozoic accreted terranes and Precambrian sialic crust in western Idaho. The ri values increase abruptly but continuously from less than 0.704 in the accreted terranes to greater than 0.708 across a narrow, 5 to 15 km zone, characterized by elongate, lens-shaped, highly deformed plutons and schistose metasedimentary and metavolcanic units. The chemical and petrologic character of the plutons changes concomitantly from ocean-arc-type, diorite-tonalite-trondhjemite units to a weakly peraluminous, calcic to calcalkalic tonalite-granodiorite-granite suite (the Idaho batholith). Plutons in both suites yield Late Cretaceous ages, but Permian through Early Cretaceous bodies are confined to the accreted terranes and early Tertiary intrusions are restricted to areas underlain by Precambrian crust. The two major terranes were juxtaposed between 75 and 130 m.y. ago, probably between 80 and 95 m.y. Oxygen and strontium isotopic ratios and Rb and Sr concentrations of the plutonic rocks document a significant upper-crustal contribution to the magmas that intrude Precambrian crust. Magmas intruding the arc terranes were derived from the upper mantle/subducted oceanic lithosphere and may have been modified by anatexis of earlier island-arc volcanic and sedimentary units. Plutons near the edge of Precambrian sialic crust represent simple mixtures of the Precambrian wall-rocks with melts derived from the upper mantle or subducted oceanic lithosphere with ri of 0.7035. Rb/Sr varies linearly with ri, producing "pseudoisochrons" with apparent "ages" close to the age of the wall rocks. Measured ??18O values of the wall rocks are less than those required for the assimilated end-member by Sr-O covariation in the plutons, however, indicating that wall-rock ??18O was reduced significantly by exchange with

  17. Strontium isotopes in otoliths of a non-migratory fish (slimy sculpin): Implications for provenance studies

    NASA Astrophysics Data System (ADS)

    Brennan, Sean R.; Fernandez, Diego P.; Zimmerman, Christian E.; Cerling, Thure E.; Brown, Randy J.; Wooller, Matthew J.

    2015-01-01

    Heterogeneity in 87Sr/86Sr ratios of river-dissolved strontium (Sr) across geologically diverse environments provides a useful tool for investigating provenance, connectivity and movement patterns of various organisms and materials. Evaluation of site-specific 87Sr/86Sr temporal variability throughout study regions is a prerequisite for provenance research, but the dynamics driving temporal variability are generally system-dependent and not accurately predictable. We used the time-keeping properties of otoliths from non-migratory slimy sculpin (Cottus cognatus) to evaluate multi-scale 87Sr/86Sr temporal variability of river waters throughout the Nushagak River, a large (34,700 km2) remote watershed in Alaska, USA. Slimy sculpin otoliths incorporated site-specific temporal variation at sub-annual resolution and were able to record on the order of 0.0001 changes in the 87Sr/86Sr ratio. 87Sr/86Sr profiles of slimy sculpin collected in tributaries and main-stem channels of the upper watershed indicated that these regions were temporally stable, whereas the Lower Nushagak River exhibited some spatio-temporal variability. This study illustrates how the behavioral ecology of a non-migratory organism can be used to evaluate sub-annual 87Sr/86Sr temporal variability and has broad implications for provenance studies employing this tracer.

  18. Strontium isotopes in otoliths of a non-migratory fish (slimy sculpin): Implications for provenance studies

    USGS Publications Warehouse

    Brennan, Sean R.; Fernandez, Diego P.; Zimmerman, Christian E.; Cerling, Thure E.; Brown, Randy J.; Wooller, Matthew J.

    2015-01-01

    Heterogeneity in 87Sr/86Sr ratios of river-dissolved strontium (Sr) across geologically diverse environments provides a useful tool for investigating provenance, connectivity and movement patterns of various organisms and materials. Evaluation of site-specific 87Sr/86Sr temporal variability throughout study regions is a prerequisite for provenance research, but the dynamics driving temporal variability are generally system-dependent and not accurately predictable. We used the time-keeping properties of otoliths from non-migratory slimy sculpin (Cottus cognatus) to evaluate multi-scale 87Sr/86Sr temporal variability of river waters throughout the Nushagak River, a large (34,700 km2) remote watershed in Alaska, USA. Slimy sculpin otoliths incorporated site-specific temporal variation at sub-annual resolution and were able to record on the order of 0.0001 changes in the 87Sr/86Sr ratio. 87Sr/86Sr profiles of slimy sculpin collected in tributaries and main-stem channels of the upper watershed indicated that these regions were temporally stable, whereas the Lower Nushagak River exhibited some spatio-teporal variability. This study illustrates how the behavioral ecology of a non-migratory organism can be used to evaluate sub-annual 87Sr/86Sr temporal variability and has broad implications for provenance studies employing this tracer.

  19. Identifying calcium sources at an acid deposition-impacted spruce forest: a strontium isotope, alkaline earth element multi-tracer approach

    Treesearch

    Thomas D. Bullen; Scott W. Bailey

    2005-01-01

    Depletion of calcium from forest soils has important implications for forest productivity and health. Ca is available to fine feeder roots from a number of soil organic and mineral sources. but identifying the primary source or changes of sources in response to environmental change is problematic. We used strontium isotope and alkaline earth element concentration...

  20. Degenerate Quantum Gases of Strontium

    NASA Astrophysics Data System (ADS)

    Stellmer, Simon; Schreck, Florian; Killian, Thomas C.

    2014-03-01

    Degenerate quantum gases of alkaline-earth-like elements open new opportunities in research areas ranging from molecular physics to the study of strongly correlated systems. These experiments exploit the rich electronic structure of these elements, which is markedly different from the one of other species for which quantum degeneracy has been attained. Specifically, alkaline-earth-like atoms, such as strontium, feature metastable triplet states, narrow intercombination lines, and a nonmagnetic, closed-shell ground state. This review covers the creation of quantum degenerate gases of strontium and the first experiments performed with this new system. It focuses on laser-cooling and evaporation schemes, which enable the creation of Bose-Einstein condensates and degenerate Fermi gases of all strontium isotopes, and shows how they are used for the investigation of optical Feshbach resonances, the study of degenerate gases loaded into an optical lattice, as well as the coherent creation of Sr2 molecules.

  1. Calcium and strontium isotope fractionation during precipitation from aqueous solutions as a function of temperature and reaction rate; II. Aragonite

    NASA Astrophysics Data System (ADS)

    AlKhatib, Mahmoud; Eisenhauer, Anton

    2017-07-01

    In order to study Strontium (Sr) partitioning and isotope fractionation of Sr and Calcium (Ca) in aragonite we performed precipitation experiments decoupling temperature and precipitation rates (R∗, μmol/m2 h) in the interval of about 2.3-4.5 μmol/m2 h. Aragonite is the only pure solid phase precipitated from a stirred solutions exposed to an atmosphere of NH3 and CO2 gases throughout the spontaneous decomposition of (NH4)2CO3. The order of reaction with respect to Ca ions is one and independent of temperature. However, the order of reaction with respect to the dissolved inorganic carbon (DIC) is temperature dependent and decreases from three via two to one as temperature increases from 12.5 and 25.0 to 37.5 °C, respectively. Strontium distribution coefficient (DSr) increases with decreasing temperature. However, R∗ responds differently depending on the initial Sr/Ca concentration and temperature: at 37.5 °C DSr increase as a function of increasing R∗ but decrease for 12.5 and 25 °C. Not seen at 12.5 and 37.5 °C but at 25 °C the DSr-R∗ gradient is also changing sign depending on the initial Sr/Ca ratio. Magnesium (Mg) adsorption coefficient between aragonite and aqueous solution (DMg) decreases with temperature but increases with R∗ in the range of 2.4-3.8 μmol/m2 h. Strontium isotope fractionation (Δ88/86Sraragonite-aq) follows the kinetic type of fractionation and become increasingly negative as a function of R∗ for all temperatures. In contrast Ca isotope fractionation (Δ44/40Caaragonite-aq) shows a different behavior than the Sr isotopes. At low temperatures (12.5 and 25 °C) Ca isotope fractionation (Δ44/40Caaragonite-aq) becomes positive as a function of R∗. In contrast, at 37.5 °C and as a function of increasing R∗ the Δ44/40Caaragonite-aq show a Sr type like behavior and becomes increasingly negative. Concerning both the discrepant behavior of DSr as a function of temperature as well as for the Ca isotope fractionation as a

  2. Oxygen and strontium isotope tracing of human migration at the Bell Beaker site Le Tumulus des Sables, France.

    NASA Astrophysics Data System (ADS)

    Willmes, Malte; James, Hannah; Boel, Ceridwen; Courtaud, Patrice; Chancerel, Antoine; McMorrow, Linda; Armstrong, Richard; Kinsley, Les; Aubert, Maxime; Eggins, Stephen; Moffat, Ian; Grün, Rainer

    2014-05-01

    Oxygen (δ18O) and strontium (87Sr/86Sr) isotopes were used as tools to investigate human migration at the early Bell Beaker site (2500-2000 BC) Le Tumulus des Sables, Saint-Laurent-Médoc, south-west France. The O and Sr isotope ratios measured in tooth enamel record the average dietary isotope signature ingested by that individual during their childhood. When this data is compared to the isotope signature of the burial site it can be used to indicate if the individual migrated into this area during their lifetime. The O isotopic composition of meteoric water changes depending on climate, temperature and quantity of precipitation. O isotope ratios in skeletal and dental remains are related to body water, which in turn is influenced by diet, physiology and climate. Most of the water consumed by large mammals comes from drinking water, typically sourced locally. Sr isotope ratios on the other hand vary between different geologic regions, depending on their age and composition. Sr is released through weathering and transported into the soil, ground and surface water, where it becomes available for uptake by plants, enters the food cycle and eventually ends up in skeletal and dental tissue where it substitutes for calcium. We analysed the teeth of 18 adult and 8 juvenile disarticulated skeletons from Le Tumulus des Sables. O isotopes were analysed in-situ by Sensitive High Resolution Ion Micro Probe (SHRIMP).The Sr isotope analysis involved drilling a 0.2-0.5 mg sample of enamel from the tooth. The Sr was then chemically separated and analysed by Thermal Ionization Mass Spectrometry (TIMS). These results were then compared to the O isoscape of Europe and bioavailable Sr isotope data (fauna, plants, soils) from the IRHUM database. We found that most of the individuals at Le Tumulus des Sables show O and Sr isotope ratios corresponding to the local environmental signal and we interpret these as part of the local population. 3 adults however show slightly higher 87Sr/86

  3. Nannofossil biostratigraphy, strontium and carbon isotope stratigraphy, cyclostratigraphy and an astronomically calibrated duration of the Late Campanian Radotruncana calcarata Zone.

    PubMed

    Wagreich, Michael; Hohenegger, Johann; Neuhuber, Stephanie

    2012-12-01

    A section from the southern (Austro-Alpine Northern Calcareous Alps) margin of the Penninic Ocean in the NW Tethys realm of Late Campanian age is investigated stratigraphically. Plankton foraminifer and nannofossil biostratigraphy designate the presence of the Globotruncana ventricosa Zone and the Radotruncana (Globotruncanita) calcarata Zone, and standard nannofossil zones CC21-UC15c(TP) and CC22ab-UC15de(TP). The combination of carbon isotope stratigraphy, strontium isotopes, and cyclostratigraphy allows a detailed chronostratigraphic correlation. Periodicity was obtained by power spectral analysis, sinusoidal regression, and Morlet wavelets. The duration of the calcarata Total Range Zone is calculated by orbital cyclicity expressed in thickness data of limestone-marl rhythmites and stable carbon isotope data. Precessional, obliquity, and short and long eccentricity cycles are identified and give an extent of c. 806 kyr for the zone. Mean sediment accumulation rates are as low as 1.99 cm/kyr and correspond well to sediment accumulation rates in similar settings. We further discuss chronostratigraphic implications of our data.

  4. Strontium isotopes in the rocks of the ophiolite complex in the Khan-Tayshiri Range (Western Mongolia)

    SciTech Connect

    Plyusnin, G.S.; Kuz'min, M.I.; Sandimirova, G.P.; Zonenshayn, L.P.

    1980-08-01

    The distribution of strontium isotopes has been examined in a section through the ophiolite complex of the Khan-Tayshiri Range (Western Mongolia). The basal parts of the complex consist of apo-dunites (/sup 87/Sr//sup 86/Sr = 0.7118 - 0.7124), and higher up in the section there are pyroxenites (0.7064 - 0.7095) and gabbros (0.7034-0.7065). The upper parts of the complex consist of pillow lavas (0.7068-0.7071), the conduits for which were a series of laminar dikes (0.7057-0.7087). An analysis of petrological and geochemical information with a selection of isotope data suggests that during the formation of the rocks of the Khan-Tayshiri Complex, three components, different in nature and chemical composition, were involved: the remains of the Earth's protolithosphere in the form of apo-dunites, a mantle quartz-tholeiite magma, and seawater. Variations in the /sup 87/Sr//sup 86/Sr ratio are associated both with the isotope composition of the original magma, and also with the conditions of its emplacement. The ultrabasic rocks are regarded as relicts of the ancient ultrabasic layer or protolithosphere of the Earth.

  5. Nannofossil biostratigraphy, strontium and carbon isotope stratigraphy, cyclostratigraphy and an astronomically calibrated duration of the Late Campanian Radotruncana calcarata Zone

    PubMed Central

    Wagreich, Michael; Hohenegger, Johann; Neuhuber, Stephanie

    2012-01-01

    A section from the southern (Austro-Alpine Northern Calcareous Alps) margin of the Penninic Ocean in the NW Tethys realm of Late Campanian age is investigated stratigraphically. Plankton foraminifer and nannofossil biostratigraphy designate the presence of the Globotruncana ventricosa Zone and the Radotruncana (Globotruncanita) calcarata Zone, and standard nannofossil zones CC21–UC15cTP and CC22ab–UC15deTP. The combination of carbon isotope stratigraphy, strontium isotopes, and cyclostratigraphy allows a detailed chronostratigraphic correlation. Periodicity was obtained by power spectral analysis, sinusoidal regression, and Morlet wavelets. The duration of the calcarata Total Range Zone is calculated by orbital cyclicity expressed in thickness data of limestone–marl rhythmites and stable carbon isotope data. Precessional, obliquity, and short and long eccentricity cycles are identified and give an extent of c. 806 kyr for the zone. Mean sediment accumulation rates are as low as 1.99 cm/kyr and correspond well to sediment accumulation rates in similar settings. We further discuss chronostratigraphic implications of our data. PMID:27087718

  6. Strontium Isotopes and Major and Minor Elements in Groundwater from the Shallow Aquifers of Southeastern North Carolina

    NASA Astrophysics Data System (ADS)

    Woods, T. L.; Hedges, E. L.; McCorkle, D. C.; Gramling, C. M.; Mulligan, A. E.; Fullagar, P. D.

    2001-05-01

    Following sampling in July, 2000, analyses of water samples from aquifers, tidal creeks, rivers, and springs in southeastern NC were added to a growing database as part of an effort to develop geochemical methods to: 1) characterize water from various groundwater and surface water reservoirs, 2) quantify groundwater discharge into estuaries and the coastal ocean, and 3) investigate saltwater intrusion into coastal aquifers. Communities in the rapidly developing region already rely heavily on groundwater from shallow limestone and calcareous sandstone aquifers like the Tertiary Castle Hayne (CH) and Cretaceous Peedee (PD). Groundwater in both aquifers is Ca- and HCO3-rich. Although major element chemistries of groundwater from different aquifers vary, strontium isotopic signatures, which change systematically with the age of aquifer materials, may prove particularly distinctive.87Sr/86Sr values for water from the CH and PD in the study area range from 0.70874-0.70909 and 0.70806 - 0.70944, respectively. 87Sr/86Sr values in the Surficial aquifer (0.70844-0.71049) show the greatest variation. Ratios of spring waters (0.70878-0.70887) suggest flow through limestones. Water from the Northeast Cape Fear River is generally characterized by decreasing 87Sr/86Sr ratios (0.70916-0.70984) and increasing strontium concentrations (0.0360-2.632) downstream. Downgradient changes in Sr-isotopes in groundwater in the study area are not yet well-constrained. However, north of the study area previous data indicate that 87Sr/86Sr for CH groundwater decreases downdip; deviations from this pattern seem to indicate intermixing of surface water or groundwater from other aquifers. Chemical characterization of water from various sources, combined with geochemical modeling and statistical analysis should permit estimation of volumes of water moving in and out of important aquifers.

  7. How wet is wet? Strontium isotopes as paleo-lake level indicators in the Chew Bahir basin (S-Ethiopia)

    NASA Astrophysics Data System (ADS)

    Junginger, A.; Vonhof, H.; Foerster, V. E.; Asrat, A.; Cohen, A. S.; Lamb, H. F.; Schaebitz, F.; Trauth, M. H.

    2016-12-01

    A major challenge in paleo-anthropology is to understand the impact of climatic changes on human evolution. The Hominin Sites and Paleo-lakes Drilling Project (HSPDP) is currently meeting that challenge by providing records that cover the last 3.7 Ma of paleoenvironmental change all located in close proximity to key paleo-anthropological findings in East Africa. One of the cored climatic archives comes from the dried up Chew Bahir basin in southern Ethiopia, where duplicate sediment cores, each 280 m long, are expected to provide valuable insights about East African environmental variability during the last >500 ka. The lake basins in the eastern branch of the East African Rift System today contain mainly shallow and alkaline lakes. However, paleo-shorelines in the form of wave cut notches, shell beds, and beach ridges are common morphological evidences for deep freshwater lakes that have filled the basins up to their overflow level during pronounced humid episodes, such as the African Humid Period (AHP, 15-5 ka). Unfortunately, further back in time, many of those morphological features disappear due to erosion and the estimation of paleo-water depths depend merely on qualitative proxies from core analyses. We here present a new method that shows high potential to translate qualitative proxy signals from sediment core analyses to quantitative climate signals in the Ethiopian Rift. The method aims at water level reconstruction of multiple paleo-lake episodes in the Chew Bahir basin using strontium isotope ratios (87Sr/86Sr, SIR) in lacustrine fossils and microfossils. SIR preserved in lacustrine fossils reflect the lithology of the drained catchment. The catchment of Chew Bahir consists mainly of Precambrian basement rocks producing high SIR in the lake waters. During humid periods, its catchment enlarged when higher elevated paleo-lakes Abaya, Chamo and Awassa were cascading down into Chew Bahir. These basins drain mainly volcanic rocks producing low SIR. First

  8. Isotopic composition of lithium, potassium, rubidium, and strontium in lunar surface material

    NASA Technical Reports Server (NTRS)

    Zaslavskiy, V. G.; Levskiy, L. K.; Murin, A. N.

    1974-01-01

    The isotopic composition of alkali and alkaline earth elements in the Luna 16 regolith was investigated by the method of thermionic emission, without chemical separation. The isotopic composition of the lithium in two regolith samples did not differ (within the limits 0.5 percent) from the mean of the terrestrial reference standard. At the same time, the observed difference (1 percent) in the isotopic composition of lithium between the samples requires further investigation and confirmation. The isotopic compositions of K and Rb did not differ within the limits of experimental error from the isotopic composition of the reference standard.

  9. Acidification processes and soil leaching influenced by agricultural practices revealed by strontium isotopic ratios

    NASA Astrophysics Data System (ADS)

    Pierson-Wickmann, Anne-Catherine; Aquilina, Luc; Weyer, Christina; Molénat, Jérôme; Lischeid, Gunnar

    2009-08-01

    In natural river systems, the chemical and isotopic composition of stream- and ground waters are mainly controlled by the geology and water-rock interactions. The leaching of major cations from soils has been recognized as a possible consequence of acidic deposition from atmosphere for over 30 years. Moreover, in agricultural areas, the application of physiological acid fertilizers and nitrogen fertilizers in the ammonia form may enhance the cation leaching through the soil profile into ground- and surface waters. This origin of leached cations has been studied on two small and adjacent agricultural catchments in Brittany, western France. The study catchments are drained by two first-order streams, and mainly covered with cambisoils, issued from the alteration and weathering of a granodiorite basement. Precipitations, soil water- and NH 4 acetate-leachates, separated minerals, and stream waters have been investigated. Chemical element ratios, such as Ba/Sr, Na/Sr and Ca/Sr ratios, as well as Sr isotopic ratios are used to constrain the relative contribution from potential sources of stream water elements. Based on Sr isotopic ratio and element concentration, soil water- and NH 4 acetate leaching indicates (1) a dominant manure/slurry contribution in the top soil, representing a cation concentrated pool, with low 87Sr/ 86Sr ratios; (2) in subsoils, mineral dissolution is enhanced by fertilizer application, becoming the unique source of cations in the saprolite. The relatively high weathering rates encountered implies significant sources of cations which are not accessory minerals, but rather plagioclase and biotite dissolution. Stream water has a very different isotopic and chemical composition compared to soil water leaching suggesting that stream water chemistry is dominated by elements issued from mineral and rock weathering. Agriculture, by applications of chemical and organic fertilizers, can influence the export of major base cations, such as Na +. Plagioclase

  10. Chemical and Strontium, Oxygen, and Carbon Isotopic Compositions of Carbonates from the Lesser Himalaya: Implications to the Strontium Isotope Composition of the Source Waters of the Ganga, Ghaghara, and the Indus Rivers

    NASA Astrophysics Data System (ADS)

    Singh, Sunil K.; Trivedi, J. R.; Pande, K.; Ramesh, R.; Krishnaswami, S.

    1998-03-01

    Samples of Precambrian carbonate (mostly dolomite) outcrops collected across the Lesser Himalaya have been analysed for their mineralogy, chemical composition, and isotope ratios of Sr, O, and C to assess the extent of their preservation and their role in contributing to the high radiogenic strontium isotope composition of the source waters of the Ganga, Ghaghara, and the Indus. Their Sr concentrations range from 20 to 363 ppm, δ 18O PDB -1.4 to -12.8‰ and Mn 11-2036 ppm. The petrography of the samples, their low Sr concentrations, and wide range of δ 18O values are suggestive of their postdepositional alteration. The 87Sr/ 86Sr of the bulk samples and their carbonate fractions are similar to one another with values ranging from 0.7064 to 0.8935 and are generally more radiogenic than that of contemporaneous seawater. Comparison of the 87Sr/ 86Sr and Sr/Ca ratios among the carbonates and silicates from the Lesser Himalaya and the source waters of the Ganga, Ghaghara, and the Indus shows that the values for the source waters overlap with those of the silicates but are much higher than those in carbonates. An upper limit of carbonate Sr in the various source waters is calculated to be between 6% and 43%, assuming that all the Ca in the rivers is of carbonate origin. The results show that on the average, weathering of the Precambrian carbonates is unlikely to be a major contributor to the highly radiogenic strontium isotope composition of these source waters; however, they can be a dominant supplier of radiogenic Sr to some rivers on a regional scale. The silicate Sr component in some of the source waters of the Ganga (Bhagirathi, Bhilangna, Alaknanda, and Ganga), Ghaghara (Kali and Sarju), and the Indus (Sutlej) was calculated from the Ca/Na, Sr/Na ratios, and strontium isotope compositions of these rivers and the silicate endmember. These calculations suggest that 33-89% of Sr in the Bhagirathi, Bhilangna, Alaknanda, Ganga, and Sarju rivers is of silicate origin

  11. The origin and migration of mud volcano fluids in Taiwan: Evidence from hydrogen, oxygen, and strontium isotopic compositions

    NASA Astrophysics Data System (ADS)

    Chao, Hung-Chun; You, Chen-Feng; Liu, Hou-Chun; Chung, Chuan-Hsiung

    2013-08-01

    Mud volcanoes are important gateways for deep fluids to migrate upward and provide windows for studying fluid/sediment interaction at depth. Fluids emitted from 40 terrestrial mud volcanoes were collected in southern and eastern Taiwan to study their chemical compositions, including H, O and Sr isotopes (87Sr/86Sr and δ88/86Sr). Relative to seawater, the mud volcano fluids are depleted in Cl, Mg, SO42-, and δD and are elevated in B, Ba, Li, and δ18O, possibly due to water-rock interaction and clay dehydration (mainly smectite to illite transformation) in the source region. The distribution of Sr in mud volcano fluids shows patterns associated with their localities and geological settings. Most fluids have higher 87Sr/86S than seawater, indicating water-rock interaction at depth. The low Na, 87Sr/86S, and high Ca fluids emitted from eastern Taiwan imply intense interaction with igneous basement. Most fluids have higher Sr/Cl and lower δ88Sr than seawater except mud volcanoes in the northern Chu-kou Fault, which emit low Sr/Cl and extremely high δ88Sr (up to 0.82‰) fluids. We performed laboratory carbonate precipitation experiments that indicate that these high Sr isotope ratios are caused by co-precipitation of carbonates from high alkalinity fluids. Mud volcano fluids in Taiwan originate at depth and their chemical compositions are controlled by the host rock, degrees of water-rock interaction, and clay dehydration, but also are masked by retrograde progresses, such as carbonate precipitation during migration. Our results show that an approach combining water isotopes (δD and δ18O) and strontium isotopes (87Sr/86Sr and δ88/86Sr) provides a robust tool for tracing fluid sources and migration pathways in accretionary prisms.

  12. Strontium-rich injectable hybrid system for bone regeneration.

    PubMed

    Neves, Nuno; Campos, Bruno B; Almeida, Isabel F; Costa, Paulo C; Cabral, Abel Trigo; Barbosa, Mário A; Ribeiro, Cristina C

    2016-02-01

    Current challenges in the development of scaffolds for bone regeneration include the engineering of materials that can withstand normal dynamic physiological mechanical stresses exerted on the bone and provide a matrix capable of supporting cell migration and tissue ingrowth. The objective of the present work was to develop and characterize a hybrid polymer–ceramic injectable system that consists of an alginate matrix crosslinked in situ in the presence of strontium(Sr), incorporating a ceramic reinforcement in the form of Sr-rich microspheres. The incorporation of Sr in the microspheres and in the vehicle relies on the growing evidence that Sr has beneficial effects in bone remodeling and in the treatment of osteopenic disorders and osteoporosis. Sr-rich porous hydroxyapatite microspheres with a uniform size and a mean diameter of 555 μm were prepared, and their compression strength and friability tested. A 3.5% (w/v) ultrapure sodium alginate solution was used as the vehicle and its in situ gelation was promoted by the addition of calcium (Ca) or Sr carbonate and Glucone-δ-lactone. Gelation times varied with temperature and crosslinking agent, being slower for Sr than for Ca, but adequate for injection in both cases. Injectability was evaluated using a device employed in vertebroplasty surgical procedures, coupled to a texture analyzer in compression mode. Compositions with 35%w of microspheres presented the best compromise between injectability and compression strength of the system, the force required to extrude it being lower than 100 N.Micro CT analysis revealed a homogeneous distribution of the microspheres inside the vehicle, and a mean inter-microspheres space of 220 μm. DMA results showed that elastic behavior of the hybrid is over the viscous one and that the higher storage modulus was obtained for the 3.5%Alg–35%Sr-HAp-Sr formulation.

  13. Do Strontium Isotope Ratios of Animal Bone and Teeth Really Reflect the Isotope Ratios of its birth- and growth-places?

    NASA Astrophysics Data System (ADS)

    Minami, M.; Goto, A.; Suzuki, K.; Kato, T.; Watanabe, K.; Hasegawa, T.

    2007-12-01

    Strontium enters the human body through the food chain as nutrients pass from bedrock through soil and water to plants and animals. Strontium substitutes for calcium in the hydroxyapatite mineral of skeletal tissue, and is stored there. 87Sr/86Sr ratios in an individual's bone and teeth could directly reflect the isotopic ratios found in the plants and animals that she or he consumed, which reflect the isotope ratios found in the soil and bedrock of that geologic region. Therefore, 87Sr/86Sr ratios of human skeletons could be useful tools for assessing human residential mobility in prehistory, and many studies on them have been often made. In this study, to evaluate whether the 87Sr/86Sr ratio of a bone or teeth really reflects the isotopic ratios of its birth and growth places, several bone and teeth samples were measured for 87Sr/86Sr ratios, compared with 87Sr/86Sr ratios of geological samples in their growth-places. Bone and teeth samples were leached with 5% acetic acid. After drying, samples were ashed in a muffle furnace at 825°C for 8h, and then digested in nitric acid, followed by cation exchange chromatography with 2.4M hydrochloric acid. 87Sr/86Sr ratios were measured using a thermal ionization mass Spectrometer (VG Sector 54) or an inductively coupled plasma mass spectrometer (Finnigan ELEMENT2). A modern boar bone collected at Asuke, Toyota City, Aichi prefecture, Japan showed a 87Sr/86Sr of 0.71001±0.00002 (2 σ), while stream sediments in the Asuke area showed around 0.710 (Asahara et al., 2006). The 87Sr/86Sr ratio of a modern black bass bone collected from Lake Biwa, Shiga prefecture, Japan was 0.71215±0.00002, while those of surface water in Lake Biwa was 0.71233±0.00002. The similar 87Sr/86Sr ratios between bone and its provenance geology could indicate that the 87Sr/86Sr ratios of bones reflect the isotopic ratios of the birth- and growth-places. The more results of modern and fossil skeletons will be shown in our presentation.

  14. Enhanced magnetic trap loading for atomic strontium

    NASA Astrophysics Data System (ADS)

    Barker, D. S.; Reschovsky, B. J.; Pisenti, N. C.; Campbell, G. K.

    2015-10-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a magneto-optical trap. This is achieved by adding a depumping laser tuned to the P31→S31 (688-nm) transition. The depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65% for the bosonic isotopes and up to 30% for the fermionic isotope of strontium. We optimize this trap loading strategy with respect to the 688-nm laser detuning, intensity, and beam size. To understand the results, we develop a one-dimensional rate equation model of the system, which is in good agreement with the data. We discuss the use of other transitions in strontium for accelerated trap loading and the application of the technique to other alkaline-earth-like atoms.

  15. A high continental weathering flux into Paleoarchean seawater revealed by strontium isotope analysis of 3.26 Ga barite

    NASA Astrophysics Data System (ADS)

    Satkoski, Aaron M.; Lowe, Donald R.; Beard, Brian L.; Coleman, Max L.; Johnson, Clark M.

    2016-11-01

    Controls on Archean seawater chemistry remain controversial. Many studies have suggested that it was largely controlled by oceanic hydrothermal fluid circulation. Recent work, however, from clastic sequences, Hf-O isotope data from detrital zircons, and models for the Rb/Sr evolution of the continental crust suggest that intense continental weathering and low-temperature surface alteration were more important than previously thought during the early Archean. This is consistent with biogeochemical studies that suggest the Archean had a diverse microbial ecology, which would, in part, need to be sustained by nutrients (e.g., phosphorus) that were derived from continental weathering. To further quantify continental weathering during the early Archean, we analyzed 3.26 Ga barite from the Fig Tree Group, South Africa for strontium, oxygen, and sulfur isotope compositions. We propose that the seawater component of the barite is characterized by 87Sr/86Sr ratios >0.701, which is significantly more radiogenic than contemporaneous mantle (∼0.7007-0.7008). The radiogenic nature of seawater at this time suggests that the continental weathering flux at 3.26 Ga had a large impact on ocean chemistry 400 million years earlier than previously suggested.

  16. Strontium isotope systematics of mixing groundwater and oil-field brine at Goose Lake in northeastern Montana, USA

    USGS Publications Warehouse

    Peterman, Zell E.; Thamke, Joanna N.; Futa, Kiyoto; Preston, Todd

    2012-01-01

    Groundwater, surface water, and soil in the Goose Lake oil field in northeastern Montana have been affected by Cl−-rich oil-field brines during long-term petroleum production. Ongoing multidisciplinary geochemical and geophysical studies have identified the degree and local extent of interaction between brine and groundwater. Fourteen samples representing groundwater, surface water, and brine were collected for Sr isotope analyses to evaluate the usefulness of 87Sr/86Sr in detecting small amounts of brine. Differences in Sr concentrations and 87Sr/86Sr are optimal at this site for the experiment. Strontium concentrations range from 0.13 to 36.9 mg/L, and corresponding 87Sr/86Sr values range from 0.71097 to 0.70828. The local brine has 168 mg/L Sr and a 87Sr/86Sr value of 0.70802. Mixing relationships are evident in the data set and illustrate the sensitivity of Sr in detecting small amounts of brine in groundwater. The location of data points on a Sr isotope-concentration plot is readily explained by an evaporation-mixing model. The model is supported by the variation in concentrations of most of the other solutes.

  17. Chondrites - Initial strontium-87/strontium-86 ratios and the early history of the solar system.

    NASA Technical Reports Server (NTRS)

    Wetherill, G. W.; Mark, R.; Lee-Hu, C.

    1973-01-01

    A sodium-poor, calcium-rich inclusion in the carbonaceous chondrite Allende had a Sr-87/Sr-86 ratio at the time of its formation of 0.69880, as low a value as that found in any other meteorite. The higher Sr-87/Sr-86 ratios found in ordinary chondrites indicate that their formation or isotopic equilibration occurred tens of millions of years later.

  18. Strontium isotope geochemistry of groundwaters and streams affected by agriculture, Locust Grove, MD

    USGS Publications Warehouse

    Böhlke, J.K.; Horan, M.

    2000-01-01

    The effects of agriculture on the isotope geochemistry of Sr were investigated in two small watersheds in the Atlantic coastal plain of Maryland. Stratified shallow oxic groundwaters in both watersheds contained a retrievable record of increasing recharge rates of chemicals including NO3/-, Cl, Mg, Ca and Sr that were correlated with increasing fertilizer use between about 1940 and 1990. The component of Sr associated with recent agricultural recharge was relatively radiogenic (87Sr/86Sr = 0.715) and it was overwhelming with respect to Sr acquired naturally by water-rock interactions in the oxidized, non-calcareous portion of the saturated zone. Agricultural groundwaters that penetrated relatively unoxidized calcareous glauconitic sediments at depth acquired an additional component of Sr from dissolution of early tertiary marine CaCO3 (87Sr/86Sr=0.708) while undergoing O2 reduction and denitrification. Ground-water discharge contained mixtures of waters of various ages and redox states. Two streams draining the area are considered to have higher 87Sr/86Sr ratios and NO3/- concentrations than they would in the absence of agriculture; however, the streams have consistently different 87Sr/86Sr ratios and NO3/- concentrations because the average depth to calcareous reducing (denitrifying) sediments in the local groundwater flow system was different in the two watersheds. The results of this study indicate that agriculture can alter significantly the isotope geochemistry of Sr in aquifers and streams and that the effects could vary depending on the types, sources and amounts of fertilizers added, the history of fertilizer use and groundwater residence times. (C) 2000 Elsevier Science Ltd.

  19. Sequential isotopic determination of plutonium, thorium, americium, strontium and uranium in environmental and bioassay samples.

    PubMed

    Wang, Jeng-Jong; Chen, Ing-Jane; Chiu, Jih-Hung

    2004-01-01

    A procedure has been developed to provide sequential analysis of 238Pu, 230Th, 241Am, 238U, and 90Sr in environmental and bioassay samples. Tracers and/or carriers (242Pu, 243Am, 232U, and stable strontium) are added into the sample as chemical yield monitors, and then, plutonium, thorium, strontium, americium, and uranium are sequentially separated and purified by Dowex ion-exchange resin, EiChroM Sr-resin, EiChroM TRU-resin, and Chelate-100 resin, respectively. The radioactivities of 90Sr and the actinides are measured using the liquid scintillation counter and alpha-particle spectrometer, respectively. Acidified water, glass-fiber air filter, soil, synthetic urine and synthetic feces samples of US National Institute of Standard and Technology Radiochemical Intercomparison Program(NRIP) were analyzed to verify this method. All the analytical results of 238Pu, 230Th, 90Sr, 241Am and 238U meet the traceability limit per ANSI N42.22, and when appropriate, evaluation of radiobioassay measurement bias and precision per ANSI N13.30.

  20. Determining flow, recharge, and vadose zonedrainage in anunconfined aquifer from groundwater strontium isotope measurements, PascoBasin, WA

    SciTech Connect

    mjsingleton@lbl.gov

    2004-06-29

    Strontium isotope compositions (87Sr/86Sr) measured in groundwater samples from 273 wells in the Pasco Basin unconfined aquifer below the Hanford Site show large and systematic variations that provide constraints on groundwater recharge, weathering rates of the aquifer host rocks, communication between unconfined and deeper confined aquifers, and vadose zone-groundwater interaction. The impact of millions of cubic meters of wastewater discharged to the vadose zone (103-105 times higher than ambient drainage) shows up strikingly on maps of groundwater 87Sr/86Sr. Extensive access through the many groundwater monitoring wells at the site allows for an unprecedented opportunity to evaluate the strontium geochemistry of a major aquifer, hosted primarily in unconsolidated sediments, and relate it to both long term properties and recent disturbances. Groundwater 87Sr/86Sr increases systematically from 0.707 to 0.712 from west to east across the Hanford Site, in the general direction of groundwater flow, as a result of addition of Sr from the weathering of aquifer sediments and from diffuse drainage through the vadose zone. The lower 87Sr/86Sr groundwater reflects recharge waters that have acquired Sr from Columbia River Basalts. Based on a steady-state model of Sr reactive transport and drainage, there is an average natural drainage flux of 0-1.4 mm/yr near the western margin of the Hanford Site, and ambient drainage may be up to 30 mm/yr in the center of the site assuming an average bulk rock weathering rate of 10-7.5 g/g/yr.

  1. Calcium and strontium isotope fractionation in aqueous solutions as a function of temperature and reaction rate; I. Calcite

    NASA Astrophysics Data System (ADS)

    AlKhatib, Mahmoud; Eisenhauer, Anton

    2017-07-01

    In order to study Strontium (Sr) partitioning and isotope fractionation of Sr and Calcium (Ca) in calcite we performed precipitation (T) experiments decoupling temperature and precipitation rate (R∗). Calcite was precipitated at 12.5, 25.0 and 37.5 °C by diffusing NH3 and CO2 gases into aqueous solutions closely following the experimental setup of Lemarchand et al. (2004). The precipitation rate (R∗) for every sample was determined applying the initial rate method and from the specific surface area of almost all samples for each reaction. The order of reaction with respect to Ca2+ ions was determined to be one and independent of T. However, the order of reaction with respect to HCO3- changed from three to one as temperature increases from 12.5, 25 °C and 37.5 °C. Strontium incorporated into calcite (expressed as DSr = [Sr/Ca]calcite/[Sr/Ca]solution) was found to be R∗ and T dependent. As a function of increasing R∗ the Δ88/86Sr-values become more negative and as temperature increases the Δ88/86Sr values also increase at constant R∗. The DSr and Δ88/86Sr-values are correlated to a high degree and depend only on R∗ being independent of temperature, complexation and varying initial ratios. Latter observation may have important implications for the study of diagenesis, the paleo-sciences and the reconstruction of past environmental conditions. Calcium isotope fractionation (Δ44/40Ca) was also found to be R∗ and T dependent. For 12.5 and 25.0 °C we observe a general increase of the Δ44/40Ca values as a function of R∗ (Lemarchand et al. type behavior, Lemarchand et al. (2004)). Whereas at 37.5 °C a significant decreasing Δ44/40Ca is observed relative to increasing R∗ (Tang et al. type behavior, Tang et al. (2008)). In order to reconcile the discrepant observations we suggest that the temperature triggered change from a Ca2+-NH3-aquacomplex covalent controlled bonding to a Ca2+-H2O-aquacomplex van-der-Waals controlled bonding caused the change

  2. Neodymium, strontium, and lead isotopes in the Maloin Ranch Pluton, Wyoming: Implications for the origin of evolved rocks at anorthosite margins

    SciTech Connect

    Kolker, A.; Hanson, G.N. ); Frost, C.D. ); Geist, D.J. )

    1991-08-01

    Neodymium, strontium, and lead isotopic data are used in this study to investigate the origin of chemically evolved rocks in the Maloin Ranch Pluton, a composite body that borders and intrudes the Laramie Anorthosite. In the Maloin Ranch Pluton, these include ferrodiorite at the base of the intrusion, overalain progressively by fine-grained monzonite, monzosyenite, and porphyritic granite. Biotite gabbro and fine-grained granitic dikes are present locally at various levels of this sequence. The origin of the evolved rocks and their possible relation to associated anorthositic bodies has been much debated. In the Maloin Ranch Pluton, each rock type has distinct isotopic characteristics which, together with trace-element data previously reported, suggest different source characteristics for each member. Strontium and neodymium isotopic data for Maloin Ranch ferrodiorite and Laramie anorthositic rocks show considerable overlap, consistent with a comagmatic relation. Biotite gabbro is chemically and isotopically the most primitive rock type in the Maloin Ranch Pluton. The data suggest that biotite gabbro has a mantle source, but has undergone extensive fractionation in the crust. The authors' results suggest that the remainder (and bulk) of the intrusion formed by partial melting of the lower crust due to the emplacement of the Laramie Anorthosite. Trace-element and isotopic characteristics of the fine-grained monzonite are explained by partial melting of mantle-dervied lower crust, added to the margin of the Archean Wyoming craton at about 1.8 Ga. Neodymium, strontium, and lead isotope data for Maloin Ranch monzosyenite and porphyritic granite also suggest a lower crustal source.

  3. Chemical weathering of a soil chronosequence on granitoid alluvium: II. Mineralogic and isotopic constraints on the behavior of strontium

    USGS Publications Warehouse

    Bullen, T.; White, A.; Blum, A.; Harden, J.; Schulz, M.

    1997-01-01

    The use of strontium isotopes to evaluate mineral weathering and identify sources of base cations in catchment waters requires an understanding of the behavior of Sr in the soil environment as a function of time. Our approach is to model the temporal evolution of 87Sr/86Sr of the cation exchange pool in a soil chronosequence developed on alluvium derived from central Sierra Nevada granitoids during the past 3 Ma. With increasing soil age, 87Sr/86Sr of ammonium-acetate extractable Sr initially decreases from values typical of K-feldspar to those of plagioclase and hornblende and then remains constant, even though plagioclase and hornblende are absent from the soils after approximately 1 Ma of weathering. The temporal variation of 87Sr/86Sr of exchangeable Sr is modeled by progressively equilibrating Sr derived from mineral weathering and atmospheric deposition with Sr on exchange sites as waters infiltrate a soil column. Observed decreases in quartz-normalized modal abundances of plagioclase, hornblende, and K-feldspar with time, and the distinct 87Sr/86Sr values of these minerals can be used to calculate Sr flux from weathering reactions. Hydrobiotites in the soils have nearly constant modal abundances, chemistry, and 87Sr/86Sr over the chronosequence and provide negligible Sr input to weathering solutions. The model requires time and soil horizon-dependent changes in the amount of exchangeable Sr and the efficiency of Sr exchange, as well as a biologic cycling term. The model predicts that exchangeable Sr initially has 87Sr/86Sr identical to that of K-feldspar, and thus could be dominated by Sr leached from K-feldspar following deposition of the alluvium. The maximum value of 87Sr/86Sr observed in dilute stream waters associated with granitoids of the Yosemite region is likewise similar to that of the K-feldspars, suggesting that K-feldspar and not biotite may be the dominant source of radiogenic Sr in the streams. This study reveals that, when attempting to use

  4. Chemical and strontium isotope characterization of rainwater in Beijing during the 2008 Olympic year

    NASA Astrophysics Data System (ADS)

    Xu, Zhifang; Tang, Yang; Ji, Jianpeng

    2012-04-01

    To improve the air quality during the 2008 Beijing Olympic Games, the Beijing Municipal Government enforced a series of emission control measures. This provided a valuable case study to evaluate the effectiveness of these aggressive measures on mitigating air pollution and improving the atmospheric environment. In this paper, we report the first results of the chemical and Sr isotopic compositions of the rainwater in Beijing during the 2008 Olympic year. The ionic composition of samples show that Ca2 + and NH4+ were the dominant cations, accounting for about 76-97% of the total cations, and that SO42 - and NO3- were the major anions, accounting for 61-91% of the total anions measured. Using Na as the indicator of marine origin and Al as that of terrestrial inputs, the proportions of sea salt and terrestrial elements were estimated from elemental ratios. The calculated results indicate that the major chemical components were mainly of non-sea-salt origin. Good correlation between Ca2 + and Sr2 + (R2 = 0.85) in rainwater samples indicates the potential of Sr as a provenance tracer for Ca. Sr2 + concentrations in rainwater samples ranged from 0.01 to 2.87 μmol l- 1, with 87Sr/86Sr ratios from 0.7092 to 0.7109. All of the samples had a 87Sr/86Sr ratio higher than that of seawater. The 87Sr/86Sr isotopic and elemental ratio systems show that the data set of rainwater was mainly distributed between the seawater end-member (~ 0.70917) and the soil dust end-member (0.7111-0.7115), and the analysis indicate that the effect of anthropogenic inputs could decrease in 2008. Comparisons of the chemical composition of the rainwater in different periods show that all chemical components, except NH4+, had the lowest concentration levels during the Olympic Game period. The VWM concentrations of major ions in the rainwater decreased significantly during the Olympic period by up to 29% for SO42 -, 39% for NO3-, 38% for Ca2 +, 51% for Mg2 +, 57% for K+, and 44% for Na+, compared with

  5. Strontium and neodymium isotopes in hot springs on the East Pacific Rise and Guaymas Basin

    NASA Technical Reports Server (NTRS)

    Piepgras, D. J.; Wasserburg, G. J.

    1985-01-01

    Solutions collected from 21 deg N, East Pacific Rise (Epr) and Guaymas Basin, Gulf of California, are analyzed for Nd isotopic composition and Sm and Nd concentrations. The results indicate extensive but not complete isotopic exchange with Sr in the depleted oceanic crust and that Sr concentrations in these solutions are buffered. In contrast, the Nd data exhibit a wide range in isotopic composition and concentration between vents. Many samples show substantial contributions from MORB, but all have isotopic compositions below MORB, in spite of enrichments in Nd up to 100 times seawater. It is shown that the fluids must exchange Nd with a sedimentary reservoir having an isotopic composition less than Pacific seawater. Low-temperature reactions with metalliferous sediments on the flanks of the EPR may provide such a source. Using a simple box method, estimates of the hydrothermal fluxes of Nd are compared to fluxes which are necessary to maintain a radiogenic isotopic composition of about -3 in the Pacific against the influx of Antarctic waters. It is concluded that erosion from island arcs is the main source of radiogenic Nd in the Pacific.

  6. Effects of diagenesis on strontium, carbon, nitrogen and oxygen concentration and isotopic composition of bone

    NASA Astrophysics Data System (ADS)

    Nelson, Bruce K.; Deniro, Michael J.; Schoeninger, Margaret J.; De Paolo, Donald J.; Hare, P. E.

    1986-09-01

    Paleodietary analysis based on variations in the trace element and stable isotopic composition of inorganic and organic phases in fossil bone depends on the assumption that measured values reflect in vivo values. To test for postmortem alteration, we measured 87Sr /86Sr , 13C /12C , 18O /16O and 15N /14N ratios and Sr concentrations in modern and prehistoric (610 to 5470 yr old) bones of animals with marine or terrestrial diets from Greenland. Bones from modern terrestrial feeders have substantially lower Sr concentrations and more radiogenic 87Sr /86Sr ratios than those from modern marine feeders. This contrast was not preserved in the prehistoric samples, which showed almost complete overlap for both Sr concentration and isotopic composition in bones from the two types of animals. Leaching experiments, X-ray diffraction analysis and infrared spectroscopy indicate that alteration of the Sr concentration and isotopic composition in prehistoric bone probably results from nearly complete exchange with groundwater. Oxygen isotope ratios in fossil apatite carbonate also failed to preserve the original discrimination between modern terrestrial and marine feeders. The C isotope ratio of apatite carbonate did not discriminate between animals with marine or terrestrial diets in the modern samples. Even so, the ranges of apatite δ 13C values in prehistoric bone are more scattered than in modern samples for both groups, suggesting alteration had occurred. δ 13C and δ 15N values of collagen in modern bone are distinctly different for the two feeding types, and this distinction is preserved in most of the prehistoric samples. Our results suggest that postmortem alteration of dietary tracers in the inorganic phases of bone may be a problem at all archaeological sites and must be evaluated in each case. While collagen analyzed in this study was resistant to alteration, evaluation of the possibility of diagenetic alteration of its isotopic composition in bones from other

  7. Participation in proficiency test for tritium strontium and caesium isotopes in seawater 2015 (IAEA-RML-2015-02)

    NASA Astrophysics Data System (ADS)

    Visetpotjanakit, S.; Kaewpaluek, S.

    2017-06-01

    A proficiency test (PT) exercise has proposed by the International Atomic Energy Agency (IAEA) in the frame of the IAEA Technical Cooperation project RAS/7/021 “Marine benchmark study on the possible impact of the Fukushima radioactive releases in the Asia-Pacific Region for Caesium Determination in Sea Water” since 2012. In 2015 the exercise was referred to Proficiency Test for Tritium, Strontium and Caesium Isotopes in Seawater 2015 (IAEA-RML-2015-02) to analyse3H, 134Cs, 137Cs and90Sr in a seawater sample. OAP was one of the 17 laboratories from 15 countries from Asia-Pacific Region who joined the PT exercise. The aim of our participation was to validate our analytical performance for the accurate determination of radionuclides in seawater by developed methods of radiochemical analysis. OAP submitted results determining the concentration for the three elements i.e. 134Cs, 137Cs and90Sr in seawater to the IAEA. A critical review was made to check suitability of our methodology and the criteria for the accuracy, precision and trueness of our data. The results of both 134Cs and 137Cs passed all criteria which were assigned “Accepted” statuses. Whereas 90Sr analysis did not pass the accuracy test therefore it was considered as “Not accepted” Our results and all other participant results with critical comments were published in the IAEA proficiency test report.

  8. Reduced population variance in strontium isotope values informs domesticated turkey use at Chaco Canyon, New Mexico, USA

    USGS Publications Warehouse

    Grimstead, Deanna N; Reynolds, Amanda C; Hudson, Adam M; Akins, Nancy J; Betancourt, Julio L.

    2016-01-01

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

  9. The spatial patterns of water management practices are reflected in the strontium isotope ratios of human hair

    NASA Astrophysics Data System (ADS)

    Tipple, B. J.; Valenzuela, L. O.; Ehleringer, J.

    2012-12-01

    Element concentrations and isotopes of human tissues are commonly used to understand how emissions and processes within urban ecosystems affect health. Thus, it is important to understand how these elements are incorporated and flow through the urban environment and are ultimately incorporated into human tissues. Here, we designed an experiment to identify the relative importance of strontium (Sr) sources (bedrock, dust, food, and water) to hair Sr isotope ratios (87Sr/86Sr). To understand the contribution of Sr to human hair, we collected hair from individuals living in Salt Lake City, Utah. In addition to sample location, we compiled information regarding age, sex, ethnicity, and dietary habits. We found a significant association between 87Sr/86Sr value of hair and collection location. There were no significant relationships between 87Sr/86Sr value of hair and age, ethnicity, or sex. We had not predicted a relationship between 87Sr/86Sr values and collection location, because of the close proximities of sites to one another (all within an 8-km radius). We found that tap water 87Sr/86Sr values across the Salt Lake Valley varied with water management practice and this variation corresponded to hair 87Sr/86Sr value. These data suggest an additional geographically controlled source of Sr may be an important contributor to the 87Sr/86Sr value of hair. These findings suggest that local water is an important source of Sr in human hair and that hair is a sensitive temporal carrier of this environmental information. These observations have important implications to future studies of humans with regard to urban ecology, human health, forensic sciences, and anthropology.

  10. Strontium isotopes reveal distant sources of architectural timber in Chaco Canyon, New Mexico

    USGS Publications Warehouse

    English, N.B.; Betancourt, J.L.; Dean, J.S.; Quade, Jay

    2001-01-01

    Between A.D. 900 and 1150, more than 200,000 conifer trees were used to build the prehistoric great houses of Chaco Canyon, New Mexico, in what is now a treeless landscape. More than one-fifth of these timbers were spruce (Picea) or fir (Abies) that were hand-carried from isolated mountaintops 75-100 km away. Because strontium from local dust, water, and underlying bedrock is incorporated by trees, specific logging sites can be identified by comparing 87Sr/86Sr ratios in construction beams from different ruins and building periods to ratios in living trees from the surrounding mountains. 87Sr/86Sr ratios show that the beams came from both the Chuska and San Mateo (Mount Taylor) mountains, but not from the San Pedro Mountains, which are equally close. Incorporation of logs from two sources in the same room, great house, and year suggest stockpiling and intercommunity collaboration at Chaco Canyon. The use of trees from both the Chuska and San Mateo mountains, but not from the San Pedro Mountains, as early as A.D. 974 suggests that selection of timber sources was driven more by regional socioeconomic ties than by a simple model of resource depletion with distance and time.

  11. Strontium isotopes reveal distant sources of architectural timber in Chaco Canyon, New Mexico

    PubMed Central

    English, Nathan B.; Betancourt, Julio L.; Dean, Jeffrey S.; Quade, Jay

    2001-01-01

    Between A.D. 900 and 1150, more than 200,000 conifer trees were used to build the prehistoric great houses of Chaco Canyon, New Mexico, in what is now a treeless landscape. More than one-fifth of these timbers were spruce (Picea) or fir (Abies) that were hand-carried from isolated mountaintops 75–100 km away. Because strontium from local dust, water, and underlying bedrock is incorporated by trees, specific logging sites can be identified by comparing 87Sr/86Sr ratios in construction beams from different ruins and building periods to ratios in living trees from the surrounding mountains. 87Sr/86Sr ratios show that the beams came from both the Chuska and San Mateo (Mount Taylor) mountains, but not from the San Pedro Mountains, which are equally close. Incorporation of logs from two sources in the same room, great house, and year suggest stockpiling and intercommunity collaboration at Chaco Canyon. The use of trees from both the Chuska and San Mateo mountains, but not from the San Pedro Mountains, as early as A.D. 974 suggests that selection of timber sources was driven more by regional socioeconomic ties than by a simple model of resource depletion with distance and time. PMID:11572943

  12. Helium-strontium isotope constraints on mantle evolution beneath the Roman Comagmatic Province, Italy

    NASA Astrophysics Data System (ADS)

    Martelli, M.; Nuccio, P. M.; Stuart, F. M.; Burgess, R.; Ellam, R. M.; Italiano, F.

    2004-08-01

    A study of the He isotopic ratios of fluid inclusions in olivine and pyroxene from the Roman Comagmatic Province (RCP), Italy, is presented together with 87Sr/ 86Sr isotope compositions of the whole rock or pyroxene phenocrysts. A clear covariation in He and Sr isotopes is apparent, with a strong northward increase in radiogenic He and Sr being evident. He and Sr isotopes ratios range from 3He/ 4He=5.2 Ra and 87Sr/ 86Sr=0.7056 in south Campania, to 3He/ 4He=0.44 Ra and 87Sr/ 86Sr=0.715905 in the northernmost Latium. Helium isotope ratios are significantly lower than MORB values and are among the lowest yet measured in subduction zone volcanism. The 3He/ 4He of olivine and pyroxene phenocryst-hosted volatiles appear to be little influenced by posteruptive processes and magma-crust interaction. The 3He/ 4He- 87Sr/ 86Sr covariation is consistent with binary mixing between an asthenospheric mantle similar to HIMU ocean island basalts, and an enriched (radiogenic) mantle end member generated from subduction of the Ionian/Adriatic plate. The contribution of radiogenic He from metasomatic fluids and postmetasomatism radiogenic ingrowth in the wedge is strongly dependent on the initial He concentration of the mantle. Only when asthenosphere He concentrations are substantially lower than the MORB source mantle, and metasomatism occurred at the beginning of the subduction (˜30 Ma), can ingrowth in the mantle wedge account for the 3He/ 4He of the most radiogenic basalts.

  13. Accumulation of bone strontium measured by in vivo XRF in rats supplemented with strontium citrate and strontium ranelate.

    PubMed

    Wohl, Gregory R; Chettle, David R; Pejović-Milić, Ana; Druchok, Cheryl; Webber, Colin E; Adachi, Jonathan D; Beattie, Karen A

    2013-01-01

    Strontium ranelate is an approved pharmacotherapy for osteoporosis in Europe and Australia, but not in Canada or the United States. Strontium citrate, an alternative strontium salt, however, is available for purchase over-the-counter as a nutritional supplement. The effects of strontium citrate on bone are largely unknown. The study's objectives were 1) to quantify bone strontium accumulation in female Sprague Dawley rats administered strontium citrate (N=7) and compare these levels to rats administered strontium ranelate (N=6) and vehicle (N=6) over 8 weeks, and 2) to verify an in vivo X-ray fluorescence spectroscopy (XRF) system for measurement of bone strontium in the rat. Daily doses of strontium citrate and strontium ranelate were determined with the intention to achieve equivalent amounts of elemental strontium. However, post-hoc analyses of each strontium compound conducted using energy dispersive spectrometry microanalysis revealed a higher elemental strontium concentration in strontium citrate than strontium ranelate. Bone strontium levels were measured at baseline and 8 weeks follow-up using a unique in vivo XRF technique previously used in humans. XRF measurements were validated against ex vivo measurements of bone strontium using inductively coupled plasma mass spectrometry. Weight gain in rats in all three groups was equivalent over the study duration. A two-way ANOVA was conducted to compare bone strontium levels amongst the three groups. Bone strontium levels in rats administered strontium citrate were significantly greater (p<0.05) than rats administered strontium ranelate and vehicle. ANCOVA analyses were performed with Sr dose as a covariate to account for differences in strontium dosing. The ANCOVA revealed differences in bone strontium levels between the strontium groups were not significant, but that bone strontium levels were still very significantly greater than vehicle.

  14. Strontium, Lead, and Oxygen Isotopic Signatures of Mid-Miocene Silicic Volcanism in Eastern Oregon

    NASA Astrophysics Data System (ADS)

    Hess, Emily Nancy

    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 line (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

  15. Integrated management of radioactive strontium contamination in aqueous stream systems.

    PubMed

    Chaalal, O; Islam, M R

    2001-01-01

    A combination of biomass treatment, fluidized bed/membrane reactor, and a minimum-suspension fluidized bed reactor is proposed to remove strontium cations from aqueous solutions, such as those generated by nuclear reactors. After conducting a series of screening tests, three adsorbents were selected for their suitability and high adsorptive capacity. The proposed combination uses Chlorella vulgaris in a packed column, followed by the fluidized bed/membrane reactor with bentonite powder in suspension. The membrane is primarily used to retain bentonite powder in the reactor. However, the same can be designed to remove additional amount of contaminant from the aqueous stream. The final separation is carried out in a fluidized bed containing resins that are suspended with minimal airflow. In laboratory scale, a flow rate of 600 ml/h was achieved for 30 min during which period the inlet concentration of 100 mg/l was reduced to 2.5 mg/l at the outlet. Bio-encapsulation with thermophilic bacteria and subsequent separation is proposed at this point in order to reduce the concentration to an even lower level. The proposed separation scheme offers an acceptable solution to removing strontium while minimizing the generation of secondary waste.

  16. Models of earth structure inferred from neodymium and strontium isotopic abundances

    PubMed Central

    Wasserburg, G. J.; DePaolo, D. J.

    1979-01-01

    A simplified model of earth structure based on the Nd and Sr isotopic characteristics of oceanic and continental tholeiitic flood basalts is presented, taking into account the motion of crustal plates and a chemical balance for trace elements. The resulting structure that is inferred consists of a lower mantle that is still essentially undifferentiated, overlain by an upper mantle that is the residue of the original source from which the continents were derived. PMID:16592688

  17. Lead and strontium isotopes in post-glacial basalts from Iceland

    NASA Technical Reports Server (NTRS)

    Sun, S.-S.; Jahn, B.-M.

    1975-01-01

    We report here our Pb and Sr isotopic study of some post-glacial basalts (less than 12,000 yr old) from the southern part of Iceland, and use our new data to evaluate various proposed models for the genesis of volcanic rocks on Iceland. The interpretation for Icelandic rocks is also extended to the genesis of volcanic rocks on other oceanic islands of the world.

  18. Dust Deposition and Pedogenic Modification in an Arid Region: Tracing Soil Development with Strontium, Carbon, and Oxygen Isotopes

    NASA Astrophysics Data System (ADS)

    McLain, A. A.; McFadden, L. D.; Asmerom, Y.; Atudorei, N.; McDonald, E. V.; Sharp, Z.

    2003-12-01

    Numerous studies have shown that accumulation of dust in desert soils is a primary means of pedogenesis in arid regions. Dust deposition is an important factor significantly impacting, among other processes, pavement development, soil water balance and soil infiltration rates, which, in turn, strongly influence vegetation density and distribution. Establishing linkages between the timing and degree of dust deposition and subsequent soil modification with changes in the local ecosystem aid in our understanding of ecological processes and landscape evolution. The Providence Mountains and Cima Volcanic Field in the Mojave Desert, California have been the sites of several important studies concerning the origins of desert pavements, soils, and landscape evolution. More recently we have conducted strontium, and carbon and oxygen isotopic studies of the carbonate fraction in these soils utilizing contrasting parent materials (mixed plutonic and limestone alluvium, basalt flows) and surface ages (mid to late Pleistocene and Holocene) to better understand the sources, changes in composition, and overall impacts of the incorporation of eolian dust on desert soil development. Sr data documents regional differences in dust delivered to the Eastern Mojave area as compared to Southern New Mexico. We document a strong correlation between dust, Av horizon and soil profile composition. Analysis of fine material from the collected dust samples has constrained Sr compositions of dust (87Sr/86Sr = 0.7101 to 0.7107) delivered to the fans and flow surfaces. Comparisons between older and younger surfaces and with the dust data suggest that de-vegetation and de-stabilization of fan surfaces in the Holocene has caused more local recycling of dust in the region. Carbon and oxygen isotopic compositions of soil carbonate enable us to constrain modes and depth of pedogenic carbonate accumulation, and in some cases distinguish between physically recycled carbonate and re-precipitated carbonate

  19. Strontium isotope ratio variations in plagioclase phenocrysts from the Imnaha basalt

    NASA Astrophysics Data System (ADS)

    Eckberg, A. E.; Wolff, J. A.; Ramos, F. C.; Hart, G. L.

    2006-12-01

    Of all the Columbia River flood basalt formations, the Imnaha Basalt best captures the isotopic signature of the mantle plume source (see abstract by Wolff, Ramos and Patterson). It is of interest, therefore, to understand the extent to which the plume signature is compromised by magma-lithosphere interaction during transport to the surface. Whole rock 87Sr/86Sr ratios of Imnaha lavas span a narrow range of 0.7038 - 0.7042, and convey a false impression of relative isotopic uniformity. Plagioclase phenocrysts analyzed by LA-MC- ICPMS exhibit much greater variations of 0.7038 - 0.7061 for the whole formation as represented by 8 flows that we have studied. Individual plagioclase phenocrysts in the Imnaha lavas typically fall into two Sr isotope ratio populations: 0.7038 - 0.7044, and 0.7045 - 0.7051. The former population, which encompasses the range of 87Sr/86Sr in whole rocks, is more abundant among a subgroup of flows that have long been recognized as more primitive (Hooper et al., 1984), and is dominated by tabular phenocrysts, some of which are zoned with less radiogenic cores and more radiogenic rims. The less radiogenic end of this range is considered to be representative of the mantle source for the Imnaha Basalt. The latter more radiogenic group of plagioclase grains is texturally more diverse, and is more abundant in flows with relatively evolved bulk compositions. Relatively radiogenic Sr (87Sr/86Sr >0.7044) among Columbia River basalts (whole rocks) is characteristic of post-Imnaha formations, including the very voluminous Grande Ronde flows, and is thought to reflect the involvement of lithospheric components derived from crust and/or mantle. Four of the 8 Imnaha flows so far investigated contain both populations of plagioclase. These results are consistent with a model where magmas residing in crustal magma chambers experience interaction with high- 87Sr/86Sr host rock before and/or during crystallization of plagioclase and are recharged by mantle

  20. Environmental controls on the boron and strontium isotopic composition of aragonite shell material of cultured Arctica islandica

    NASA Astrophysics Data System (ADS)

    Liu, Y.-W.; Aciego, S. M.; Wanamaker, A. D., Jr.

    2015-02-01

    Ocean acidification, the decrease in ocean pH associated with increasing atmospheric CO2, is likely to impact marine organisms, particularly those that produce carbonate skeletons or shells. Therefore it is important to investigate how environmental factors (seawater pH, temperature and salinity) influence the chemical compositions in biogenic carbonates. In this study we report the first high-resolution strontium (87Sr / 86Sr and δ88 / 86Sr) and boron (δ11B) isotopic values in the aragonite shell of cultured Arctica islandica (A. islandica). The 87Sr / 86Sr ratios from both tank water and shell samples show ratios nearly identical to the open ocean, which suggests that the shell material reflects ambient ocean chemistry without terrestrial influence. The 84Sr-87Sr double spike resolved shell δ 88 / 86Sr and Sr concentration data show no resolvable change throughout the culture period and reflect no theoretical kinetic mass fractionation throughout the experiment despite a temperature change of more than 15 °C. The δ11B records from the experiment show at least a 5‰ increase through the culture season (January 2010-August 2010), with low values from beginning to week 19 and higher values hereafter. The larger range in δ11B in this experiment compared to predictions based on other carbonate organisms (2-3‰) suggests that a species-specific fractionation factor may be required. A relatively strong correlation between the Δ pH (pHshell-pHsw) and seawater pH (pHsw) was observed (R2 = 0.34), which suggests that A. islandica partly regulates the pH of the extrapallial fluid. However, this proposed mechanism only explains approximately 34% of the variance in the δ11B data. Instead, a rapid rise in δ11B after week 19 suggests that the boron uptake of the shell changes when a temperature threshold of 13 °C is reached.

  1. Age determinations and growth rates of Pacific ferromanganese deposits using strontium isotopes

    USGS Publications Warehouse

    Ingram, B.L.; Hein, J.R.; Farmer, G.L.

    1990-01-01

    87Sr 86Sr ratios, trace element and REE compositions, and textural characteristics were determined for three hydrogenetic Fe-Mn crusts, one hydrothermal deposit, and two mixed hydrothermalhydrogenetic crusts from the Pacific. The Sr isotope data are compared to the Sr seawater curve for the Cenozoic to determine the ages and growth rates of the crusts. The 87Sr 86Sr in the crusts does not increase monotonically with depth as expected if the Sr were solely derived from seawater and perfectly preserved since deposition. This indicates post-depositional exchange of Sr or heterogeneous sources for the Sr originally contained in the crusts. Textures of hydrogenetic crusts generally correlate with Sr isotopic variations. The highest porosity intervals commonly exhibit the highest 87Sr 86Sr ratios, indicating exchange with younger seawater. Intervals with the lowest porosity commonly have lower 87Sr 86Sr and may preserve the original Sr isotopic ratios. Minimum ages of crust growth inception were calculated from dense, low porosity intervals. Growth of the hydrogenetic crusts began at or after 23 Ma, although their substrates are Cretaceous. Estimated average growth rates of the three hydrogenetic crusts vary between 0.9 and 2.7 mm/Ma, consistent with published rates determined by other techniques. Within the Marshall Islands crust, growth rates for individual layers varied greatly between 1.0 and 5.4 mm/Ma. For one crust, very low 87Sr 86Sr ratios occurred in detrital-rich intervals. Hydrothermal Fe-Mn oxide from the active Lau Basin back-arc spreading axis (Valu Fa Ridge) has an 87Sr 86Sr ratio with a predominantly seawater signature ( 87Sr 86Sr 0.709196), indicating a maximum age of 0.9 Ma. One crust from an off-axis seamount west of Gorda Ridge may have begun precipitating hydrogenetically at 0.5 Ma (0.709211), and had increasing hydrothermal or volcanic input in the top half of the crust, indicated by a significantly lower 87Sr 86Sr ratio (0.709052). ?? 1990.

  2. Hot cell purification of strontium-82, 85 and other isotopes from proton irradiated molybdenum

    DOEpatents

    Bentley, Glenn E.; Barnes, John W.

    1981-01-01

    A process suitable for producing curie quantities of quite pure Sr-82,85 is given. After a Mo target is irradiated with energetic protons having energies greater than about 200 MeV, thus producing a large number of radioactive species, the particular species of Sr-82,85 are substantially separated from the other products by a 6-step process. The process comprises dissolution of the target in H.sub.2 O.sub.2, followed by use of several ion exchange resins, extraction with an organophosphorus compound, and several adjustments of pH values. Other embodiments include processes for producing relatively pure long-lived Rb isotopes, Y-88, and Zr-88.

  3. Hot cell purification of strontium-82, 85 and other isotopes from proton irradiated molybdenum

    DOEpatents

    Bentley, G.E.; Barnes, J.W.

    1979-10-17

    A process suitable for producing curie quantities of quite pure Sr-82,85 is given. After a Mo target is irradiated with energetic protons having energies greater than about 200 MeV, thus producing a large number of radioactive species, the particular species of Sr-82,85 are substantially separated from the other products by a 6-step process. The process comprises dissolution of the target in H/sub 2/O/sub 2/, followed by use of several ion exchange resins, extraction with an organophosphorus compound, and several adjustments of pH values. Other embodiments include processes for producing relatively pure long-lived Rb isotopes, Y-88, and Zr-88.

  4. Environmental controls on the boron and strontium isotopic composition of aragonite shell material of cultured Arctica islandica

    NASA Astrophysics Data System (ADS)

    Liu, Y.-W.; Aciego, S. M.; Wanamaker, A. D., Jr.

    2015-06-01

    Ocean acidification, the decrease in ocean pH associated with increasing atmospheric CO2, is likely to impact marine organisms, particularly those that produce carbonate skeletons or shells. Therefore, it is important to investigate how environmental factors (seawater pH, temperature and salinity) influence the chemical compositions in biogenic carbonates. In this study we report the first high-resolution strontium (87Sr / 86Sr and δ88 / 86Sr) and boron (δ11B) isotopic values in the aragonite shell of cultured Arctica islandica (A. islandica). The 87Sr / 86Sr ratios from both tank water and shell samples show ratios nearly identical to the open ocean, which suggests that the shell material reflects ambient ocean chemistry without terrestrial influence. The 84Sr-87Sr double-spike-resolved shell δ88 / 86Sr and Sr concentration data show no resolvable change throughout the culture period and reflect no theoretical kinetic mass fractionation throughout the experiment despite a temperature change of more than 15 °C. The δ11B records from the experiment show at least a 5‰ increase through the 29-week culture season (January 2010-August 2010), with low values from the beginning to week 19 and higher values thereafter. The larger range in δ11B in this experiment compared to predictions based on other carbonate organisms (2-3‰) suggests that a species-specific fractionation factor may be required. A significant correlation between the ΔpH (pHshell - pHsw) and seawater pH (pHsw) was observed (R2 = 0.35), where the pHshell is the calcification pH of the shell calculated from boron isotopic composition. This negative correlation suggests that A. islandica partly regulates the pH of the extrapallial fluid. However, this proposed mechanism only explains approximately 35% of the variance in the δ11B data. Instead, a rapid rise in δ11B of the shell material after week 19, during the summer, suggests that the boron uptake changes when a thermal threshold of > 13 °C is

  5. Estimating groundwater mixing and origin in an overexploited aquifer in Guanajuato, Mexico, using stable isotopes (strontium-87, carbon-13, deuterium and oxygen-18).

    PubMed

    Horst, Axel; Mahlknecht, Jürgen; Merkel, Broder J

    2007-12-01

    Stable Isotopes (strontium-87, deuterium and oxygen-18, carbon-13) have been used to reveal different sources of groundwater and mixing processes in the aquifer of the Silao-Romita Valley in the state of Guanajuato, Mexico. Calcite dissolution appeared to be the main process of strontium release leading to relatively equal (87)Sr/(86)Sr ratios of 0.7042-0.7062 throughout the study area which could be confirmed by samples of carbonate rocks having similar Sr ratios (0.7041-0.7073). delta(13)C values (-11.91- -6.87 per thousand VPDB) of groundwaters confirmed the solution of carbonates but indicated furthermore influences of soil-CO(2). Deuterium and (18)O contents showed a relatively narrow range of-80.1- -70.0 per thousand VSMOW and -10.2- -8.8 per thousand, VSMOW, respectively but are affected by evaporation and mixing processes. The use of delta(13)C together with (87)Sr/(86)Sr revealed three possible sources: (i) carbonate-controlled waters showing generally higher Sr-concentrations, (ii) fissure waters with low-strontium contents and (iii) infiltrating water which is characterized by low delta(13)C and (87)Sr/(86)Sr ratios. The third component is affected by evaporation processes taking place before and during infiltration which might be increased by extraction and reinfiltration (irrigation return flow).

  6. "Celtic migrations": fact or fiction? Strontium and oxygen isotope analysis of the Czech cemeteries of Radovesice and Kutná Hora in Bohemia.

    PubMed

    Scheeres, Mirjam; Knipper, Corina; Hauschild, Maya; Schönfelder, Martin; Siebel, Wolfgang; Pare, Christopher; Alt, Kurt W

    2014-12-01

    Strontium and oxygen isotope analysis of human remains from the early La Tène (fourth/third century BC) Czech cemeteries of Radovesice I (RAD I), Radovesice II (RAD II), and Kutná Hora were conducted to investigate the importance of residential changes during the period of the historic "Celtic migrations". In the initial phases (LT A/B), the grave goods of these cemeteries are typical for the core area of the La Tène culture, while around 300 BC (LT B2) an alteration occurs and typical Bohemian styles arise, and connections to Moravia and the Danubian region become visible. The strontium isotope ratios are highly varied with (87) Sr/(86) Sr values between 0.7062 and 0.7153 in Radovesice, and between 0.7082 and 0.7147 in Kutná Hora. The oxygen isotope data are more homogeneous and yield δ(18) Op ratios from 14.8‰ to 17.2‰ [mean: 16.2‰ ± 0.5 (1σ)] in Radovesice, and from 14.9‰ to 17.3‰ [mean: 16.5‰ ± 0.6 (1σ)] in Kutná Hora. Because the geological properties of the landscapes around the sites are variable and complex, most of the observed variations among the strontium isotope ratios may have been caused by agricultural practices, such as regularly changing farming land. Nevertheless, there are some individuals who differ completely from the regional isotopic baseline values. This suggests that at least a small part of the community migrated, which does not seem to be correlated with any particular phase of the La Tène period. Remarkably, it is mainly males who seem to be of nonlocal origin, and particularly those who were buried as warriors. Females, on the other hand, appear to have been more closely bonded to the Bohemian region. Whether the "foreign" individuals with differing isotopic compositions came from Moravia or the Danubian region remains debatable.

  7. Potential leakage between aquifers in a deeply anthropized coastal sedimentary basin (Recife, Brazil): Strontium isotope constraints

    NASA Astrophysics Data System (ADS)

    Petelet-Giraud, Emmanuelle; Cary, Lise; Hirata, Ricardo; Martins, Veridiana; Bertrand, Guillaume; Montenegro, Suzana; Pauwels, Helene; Kloppmann, Wolfram; Aquilina, Luc

    2013-04-01

    Due to an increasing demographic pressure, the Metropolitan Region of Recife (RMR) went through remarkable changes of water and land uses over the last decades. These evolutions gave rise to numerous environmental consequences, such as a dramatic decline of the piezometric levels, groundwater salinization and contamination. This degradation of natural resources is linked to the increase of water demand, punctually amplified by drought periods which induced the construction of thousands of private wells. Recife was built on the estuarine area of the Capibaribe River and other small rivers. The Recife coastal plain is located in the geographic limits of the sedimentary basins of Cabo and Pernambuco-Paraíba which consist out of fluvial and marine geologic formations. It is composed of three main aquifers: the two semi-confined Cabo and Beberibe aquifers, both underlining the superficial Boa Viagem unconfined aquifer, which is the most directly exposed to contamination, since it is connected to mangroves, rivers, estuaries and highly urbanized areas. The Boa Viagem aquifer is made of marine terraces of sand, silt and clay has an average thickness of 40 m. The Cabo aquifer occurs in the south of Recife and comprises sandstones, siltstones and mudstones, with an average thickness of 90 m. The Beberibe aquifer occurs in the north and central area of Recife with an average thickness of 100 m of sandstones with intercalations of mudstone; it is the most important one, with the highest amount of good quality water. Both the Beberibe and Cabo aquifers contain large clay levels. The hydraulic connections between the three aquifers are not well known but isotopic studies have shown that the recharge processes are similar, suggesting that exchanges may occur and may be modified or amplified by overexploitation especially between the Cabo and Boa Viagem aquifers. Two other aquifers can be found west of the city: the Barreiras aquifer, characterized by alternating well stratified

  8. A reconsideration of marine strontium budgets using both stable (δ88Sr) and radiogenic (87Sr/86Sr) systems

    NASA Astrophysics Data System (ADS)

    Pearce, C. R.; Parkinson, I. J.; Burton, K. W.

    2011-12-01

    The radiogenic strontium (Sr) isotope system is one of the most commonly used continental weathering proxies, as variations in 87Sr/86Sr throughout the geological record are thought to represent changes in the flux of continental and hydrothermal material to the oceans(1). Despite decades of research, however, it remains unclear why Sr in the modern oceans is not in steady state, with the flux-weighted inputs of radiogenic and unradiogenic Sr not balancing the rate of change observed in seawater 87Sr/86Sr over the last ~400 kyr(2). Recent recognition of significant stable Sr isotope fractionation suggests that variations in δ88Sr may offer new insights into the global cycling of Sr. Because δ88Sr is fractionated during both continental weathering(3) and carbonate precipitation(4), it can provide information on both the inputs and outputs of Sr from the oceans, and may consequently help constrain differences between weathering flux and source compositional variations over geological timescales. This study presents new δ88Sr data from numerous pore water and dust samples, which, together with δ88Sr values for global river water, rain water and hydrothermal fluids(3), complete the δ88Sr characterisation of the principal marine Sr inputs. Incorporating δ88Sr values from carbonates that are representative of the dominant output flux of Sr from the oceans(4), this enables the complete stable Sr isotope budget of the modern oceans to be determined. This is compared to the existing radiogenic Sr isotope budget, and the implications for the non-steady state cycling of Sr are discussed. (1) Palmer and Edmond (1989). EPSL, 92, 11-26. (2) Vance et al. (2009). Nature, 458, 493-496. (3) Pearce et al. (2010). AGU Fall Meeting, Abstract B21D-0342. (4) Krabbenhöft et al. (2010). GCA, 74, 4097-4109.

  9. Strontium Isotope Dating of Metalliferous Sediment in the SW Pacific Basin

    NASA Astrophysics Data System (ADS)

    Stancin, A. M.; Gleason, J. D.; Owen, B. M.; Rea, D. K.; Moore, T. C.; Hendy, I. L.; Lyle, M. W.; Blum, J. D.

    2007-12-01

    A 2 million km2 region virtually devoid of sediment was identified in the remote SW Pacific Basin during the TUIM- 3 2005 drill site survey cruise. This region, termed the "South Pacific Bare Zone", comprises ocean floor dating back to the Late Cretaceous. Within the Bare Zone, a small (1km2) abyssal valley containing sediment to a depth of 24 m was sampled using a large diameter piston core (MV0502-15JC, 31 ° 42.194'S, 143 ° 30.331'W), leading to recovery of 8.35 m of metalliferous sediment at 5082 m water depth. Fish-teeth Sr-isotope stratigraphy reveals a continuous record of sedimentation from 31 Ma to present at this site. The fish teeth age-depth profile and INAA geochemistry reveal an exponentially decreasing hydrothermal flux, with sedimentation rates approaching 0.05 mm/kyr after 20 Ma. The source of hydrothermal activity at this site was likely the Pacific- Farallon Ridge, which went extinct at 20 Ma. A second piston core (MV0502-16JC; 28 ° 05.151'S, 140 ° 14.140'W) was collected near MacDonald Seamounts located on the southeastern end of the Cook-Austral island chain outside the Bare Zone and recovered 10.5 m of hydrothermal sediment and biogenic ooze. The lower 65 cm of the core consists of a coccolith ooze. From 10 mbsf depth to 1.5 mbsf depth, the core contians reddish black zeolitic clay, while the upper 1.5 mbsf contains biogenic ooze associated with abundant Late Pleistocene foraminifera remains. Concordant nannofossil and fish teeth ages at the base of the core (27-28 Ma), and Pleistocene ages near the top of the core reinforce the validity of the Sr fish teeth method for dating hydrothermal cores. These independent records suggest that regional hydrothermal activity during the Oligocene may have been related to a series of late Eocene/early Oligocene ridge jumps, propagating rifts and seafloor spreading centers that accompanied large-scale plate tectonic reorganization of South Pacific seafloor.

  10. The strontium isotopic budget of Himalayan rivers in Nepal and Bangladesh

    SciTech Connect

    Galy, A.; France-Lanord, C. |; Derry, L.A.

    1999-07-01

    Himalayan rivers have very unusual Sr characteristics and their budget cannot be achieved by simple mixing between silicate and carbonate even if carbonates are radiogenic. The authors present Sr, O, and C isotopic data from river and rain water, bedload, and bedrock samples for the western and central Nepal Himalaya and Bangladesh, including the monsoon season. Central Himalayan rivers receive Sr from several sources: carbonate and clastic Tethyan sediments, High Himalayan Crystalline (HHC) gneisses and granitoids with minor marbles, carbonates and metasediments of the Lesser Himalaya (LH), and Miocene-Recent foreland basin sediment from the Siwaliks group and the modern flood plain. In the Tethyan Himalaya rivers have dissolved [Sr] {approx} 6 {micro}mol/l and {sup 87}Sr/{sup 86}Sr {approx} 0.717, with a large contribution from moderately radiogenic carbonate. Rivers draining HHC gneisses are very dilute with [Sr] {approx} 0.2 {micro}mol/l and {sup 87}Sr/{sup 86}Sr {approx} 0.74. Lesser Himalayan streams also have low [Sr] {approx} 0.4 {micro}mol/l and are highly radiogenic ({sup 87}Sr/{sup 86}Sr {ge} 0.78). Highly radiogenic carbonates of the LH do not contribute significantly to the Sr budget because they are sparse and have very low [Sr]. In large rivers exiting the Himalaya, Sr systematics can be modeled as a mixture between Tethyan rivers, where slightly radiogenic carbonates (mean {sup 87}Sr/{sup 86}Sr {approx} 0.715) are the main source of Sr, and Lesser Himalaya waters, where extremely radiogenic silicates (> 0.8) are the main source of Sr. HHC waters are less important because of their low [Sr]. Rivers draining the Siwaliks foreland basin sediments have [Sr] {approx} 4 {micro}mol/l and {sup 87}Sr/{sup 86}Sr {approx} 0.725. Weathering of silicates in the Siwaliks and the flood plain results in a probably significant radiogenic (0.72--0.74) input to the Ganges and Brahamputra (G-B), but quantification of this flux is limited by uncertainties in the

  11. Strontium isotope record of seasonal scale variations in sediment sources and accumulation in low-energy, subtidal areas of the lower Hudson River estuary

    USGS Publications Warehouse

    Smith, J.P.; Bullen, T.D.; Brabander, D.J.; Olsen, C.R.

    2009-01-01

    Strontium isotope (87Sr/86Sr) profiles in sediment cores collected from two subtidal harbor slips in the lower Hudson River estuary in October 2001 exhibit regular patterns of variability with depth. Using additional evidence from sediment Ca/Sr ratios, 137Cs activity and Al, carbonate (CaCO3), and organic carbon (OCsed) concentration profiles, it can be shown that the observed variability reflects differences in the relative input and trapping of fine-grained sediment from seaward sources vs. landward sources linked to seasonal-scale changes in freshwater flow. During high flow conditions, the geochemical data indicate that most of the fine-grained sediments trapped in the estuary are newly eroded basin materials. During lower (base) flow conditions, a higher fraction of mature materials from seaward sources with higher carbonate content is trapped in the lower estuary. Results show that high-resolution, multi-geochemical tracer approaches utilizing strontium isotope ratios (87Sr/86Sr) can distinguish sediment sources and constrain seasonal scale variations in sediment trapping and accumulation in dynamic estuarine environments. Low-energy, subtidal areas such as those in this study are important sinks for metastable, short-to-medium time scale sediment accumulation. These results also show that these same areas can serve as natural recorders of physical, chemical, and biological processes that affect particle and particle-associated material dynamics over seasonal-to-yearly time scales. ?? 2009.

  12. Boron and Strontium isotope systematics in deeply subducted alpine-serpentinites: evidence of high-11B fluid flow

    NASA Astrophysics Data System (ADS)

    Tonarini, Sonia; Scambelluri, Marco

    2010-05-01

    Boron and strontium isotope systematics are widely applied tracers to understand recycling processes during subduction. However, very few studies are addressed to the geochemical behaviour of these isotope ratios in high (HP) to ultrahigh-pressure (UHP) serpentinites that experienced pressure-temperature conditions similar to those of modern subduction zones. Here we present delta-11B and 87Sr/86Sr ratios of the Erro-Tobbio peridotite (Ligurian Alps) a slice of serpentinized mantle involved in subduction and high-pressure recrystallization during the Alpine orogeny. The analyzed sample set includes serpentinized peridotite samples recrystallized at increasing P-T conditions: from relatively low P-T (chrysotile and lizardite are the dominant serpentine minerals) to eclogite-facies conditions (antigorite + olivine + Ti clinohumite form the stable paragenesis). During subduction, ductile deformation under HP conditions was focused in serpentinite mylonite shear zones (high-strain domains) surrounding volumes of HP serpentinized peridotite unaffected by plastic deformation (low-strain domains). The latter diffusely preserve serpentinized mantle peridotites with low P-T overprint retaining pristine mantle textures and assemblages. In general, the delta-11B in these products is heavy, with the majority of samples exceeding delta-11B of 16 permil and reaching extreme values of + 24 permil. The 87Sr/86Sr ratios range between 0.7044 and 0.7065, significantly lower than the values of serpentinites formed during interaction with seawater-dominated fluids and close to the seawater 87Sr/86Sr. In more detail, the low P-T serpentinized peridotites are characterized by the wider range of delta-11B variability (+3.8 to +24 permil). The low-strain HP peridotites show a comparably wide range in delta-11B (+6.8 to +20 permil). More homogeneous and generally higher delta-11B were measured in HP mylonitic serpentinites (delta-11B between +16.7 and +24 permil): these rocks also display

  13. Dietary Strontium Increases Bone Mineral Density in Intact Zebrafish (Danio rerio): A Potential Model System for Bone Research

    PubMed Central

    Padgett-Vasquez, Steve; Garris, Heath W.; Nagy, Tim R.; D'Abramo, Louis R.; Watts, Stephen A.

    2010-01-01

    Abstract Zebrafish (Danio rerio) skeletal bone possesses properties similar to human bone, which suggests that they may be used as a model to study mineralization characteristics of the human Haversian system, as well as human bone diseases. One prerequisite for the use of zebrafish as an alternative osteoporotic bone model is to determine whether their bone displays functional plasticity similar to that observed in other bone models. Strontium citrate was supplemented into a laboratory-prepared diet (45% crude protein) to produce dietary strontium levels of 0%, 0.63%, 1.26%, 1.89%, and 2.43% and fed ad libitum twice daily for 12 weeks to 28-day-old intact zebrafish. Length was determined at 4-week intervals, and both weight and length were recorded at 12 weeks. At 12 weeks, seven zebrafish from each dietary level were analyzed for total bone mineral density by microcomputed tomography. Dietary strontium citrate supplementation significantly (p < 0.05) increased zebrafish whole-body and spinal column bone mineral density. In addition, trace amounts of strontium were incorporated into the scale matrix in those zebrafish that consumed strontium-supplemented diets. These findings suggest that zebrafish bone displays plasticity similar to that reported for other bone models (i.e., rat, mouse, and monkey) that received supplements of strontium compounds and zebrafish should be viewed as an increasingly valuable bone model. PMID:20874492

  14. Dietary strontium increases bone mineral density in intact zebrafish (Danio rerio): a potential model system for bone research.

    PubMed

    Siccardi, Anthony J; Padgett-Vasquez, Steve; Garris, Heath W; Nagy, Tim R; D'Abramo, Louis R; Watts, Stephen A

    2010-09-01

    Zebrafish (Danio rerio) skeletal bone possesses properties similar to human bone, which suggests that they may be used as a model to study mineralization characteristics of the human Haversian system, as well as human bone diseases. One prerequisite for the use of zebrafish as an alternative osteoporotic bone model is to determine whether their bone displays functional plasticity similar to that observed in other bone models. Strontium citrate was supplemented into a laboratory-prepared diet (45% crude protein) to produce dietary strontium levels of 0%, 0.63%, 1.26%, 1.89%, and 2.43% and fed ad libitum twice daily for 12 weeks to 28-day-old intact zebrafish. Length was determined at 4-week intervals, and both weight and length were recorded at 12 weeks. At 12 weeks, seven zebrafish from each dietary level were analyzed for total bone mineral density by microcomputed tomography. Dietary strontium citrate supplementation significantly (p < 0.05) increased zebrafish whole-body and spinal column bone mineral density. In addition, trace amounts of strontium were incorporated into the scale matrix in those zebrafish that consumed strontium-supplemented diets. These findings suggest that zebrafish bone displays plasticity similar to that reported for other bone models (i.e., rat, mouse, and monkey) that received supplements of strontium compounds and zebrafish should be viewed as an increasingly valuable bone model.

  15. Evidence for Patterns of Selective Urban Migration in the Greater Indus Valley (2600-1900 BC): A Lead and Strontium Isotope Mortuary Analysis.

    PubMed

    Valentine, Benjamin; Kamenov, George D; Kenoyer, Jonathan Mark; Shinde, Vasant; Mushrif-Tripathy, Veena; Otarola-Castillo, Erik; Krigbaum, John

    2015-01-01

    Just as modern nation-states struggle to manage the cultural and economic impacts of migration, ancient civilizations dealt with similar external pressures and set policies to regulate people's movements. In one of the earliest urban societies, the Indus Civilization, mechanisms linking city populations to hinterland groups remain enigmatic in the absence of written documents. However, isotopic data from human tooth enamel associated with Harappa Phase (2600-1900 BC) cemetery burials at Harappa (Pakistan) and Farmana (India) provide individual biogeochemical life histories of migration. Strontium and lead isotope ratios allow us to reinterpret the Indus tradition of cemetery inhumation as part of a specific and highly regulated institution of migration. Intra-individual isotopic shifts are consistent with immigration from resource-rich hinterlands during childhood. Furthermore, mortuary populations formed over hundreds of years and composed almost entirely of first-generation immigrants suggest that inhumation was the final step in a process linking certain urban Indus communities to diverse hinterland groups. Additional multi disciplinary analyses are warranted to confirm inferred patterns of Indus mobility, but the available isotopic data suggest that efforts to classify and regulate human movement in the ancient Indus region likely helped structure socioeconomic integration across an ethnically diverse landscape.

  16. Evidence for Patterns of Selective Urban Migration in the Greater Indus Valley (2600-1900 BC): A Lead and Strontium Isotope Mortuary Analysis

    PubMed Central

    Valentine, Benjamin; Kamenov, George D.; Kenoyer, Jonathan Mark; Shinde, Vasant; Mushrif-Tripathy, Veena; Otarola-Castillo, Erik; Krigbaum, John

    2015-01-01

    Just as modern nation-states struggle to manage the cultural and economic impacts of migration, ancient civilizations dealt with similar external pressures and set policies to regulate people’s movements. In one of the earliest urban societies, the Indus Civilization, mechanisms linking city populations to hinterland groups remain enigmatic in the absence of written documents. However, isotopic data from human tooth enamel associated with Harappa Phase (2600-1900 BC) cemetery burials at Harappa (Pakistan) and Farmana (India) provide individual biogeochemical life histories of migration. Strontium and lead isotope ratios allow us to reinterpret the Indus tradition of cemetery inhumation as part of a specific and highly regulated institution of migration. Intra-individual isotopic shifts are consistent with immigration from resource-rich hinterlands during childhood. Furthermore, mortuary populations formed over hundreds of years and composed almost entirely of first-generation immigrants suggest that inhumation was the final step in a process linking certain urban Indus communities to diverse hinterland groups. Additional multi disciplinary analyses are warranted to confirm inferred patterns of Indus mobility, but the available isotopic data suggest that efforts to classify and regulate human movement in the ancient Indus region likely helped structure socioeconomic integration across an ethnically diverse landscape. PMID:25923705

  17. Rb-Sr whole-rock and mineral ages, K-Ar, 40Ar/39Ar, and U-Pb mineral ages, and strontium, lead, neodymium, and oxygen isotopic compositions for granitic rocks from the Salinian Composite Terrane, California:

    USGS Publications Warehouse

    Kistler, R.W.; Champion, D.E.

    2001-01-01

    This report summarizes new and published age and isotopic data for whole-rocks and minerals from granitic rocks in the Salinian composite terrane, California. Rubidium-strontium whole-rock ages of plutons are in two groups, Early Cretaceous (122 to 100 Ma) and Late Cretaceous (95 to 82 Ma). Early Cretaceous plutons occur in all granitic rock exposures from Bodega Head in the north to those from the Santa Lucia and Gabilan Ranges in the central part of the terrane. Late Cretaceous plutons have been identified in the Point Reyes Peninsula, the Santa Lucia and the Gabilan Ranges, and in the La Panza Range in the southern part of the terrane. Ranges of initial values of isotopic compositions are 87Sr/86Sr, 0.7046-0.7147, δ18O, +8.5 to +12.5 per mil, 206Pb/204Pb, 18.901-19.860, 207Pb/204Pb, 15.618-15.814, 208Pb/204Pb, 38.569- 39.493, and εNd, +0.9 to -8.6. The initial 87Sr/86Sr=0.706 isopleth is identified in the northern Gabilan Range and in the Ben Lomond area of the Santa Cruz Mountains, in Montara Mountain, in Bodega Head, and to the west of the Farallon Islands on the Cordell Bank. This isotopic boundary is offset about 95 miles (160km) by right-lateral displacements along the San Gregorio-Hosgri and San Andreas fault systems.

  18. Feasibility study for the processing of Hanford Site cesium and strontium isotopic sources in the Hanford Waste Vitrification Plant

    SciTech Connect

    Anantatmula, R.P.; Watrous, R.A.; Nelson, J.L.; Perez, J.M.; Peters, R.D.; Peterson, M.E.

    1991-09-01

    The final environmental impact statement for the disposal of defense-related wastes at the Hanford Site (Final Environmental Impact Statement: Disposal of Hanford Defense High-Level, Transuranic and Tank Wastes [HDW-EIS] [DOE 1987]) states that the preferred alternative for disposal of cesium and strontium wastes at the Hanford Site will be to package and ship these wastes to the commercial high-level waste repository. The Record of Decision for this EIS states that before shipment to a geologic repository, these wastes will be packaged in accordance with repository waste acceptance criteria. However, the high cost per canister for repository disposal and uncertainty about the acceptability of overpacked capsules by the repository suggest that additional alternative means of disposal be considered. Vitrification of the cesium and strontium salts in the Hanford Waste Vitrification Plant (HWVP) has been identified as a possible alternative to overpacking. Subsequently, Westinghouse Hanford Company`s (Westinghouse Hanford) Projects Technical Support Office undertook a feasibility study to determine if any significant technical issues preclude the vitrification of the cesium and strontium salts. Based on the information presented in this report, it is considered technically feasible to blend the cesium chloride and strontium fluoride salts with neutralized current acid waste (NCAW) and/or complexant concentrate (CC) waste feedstreams, or to blend the salts with fresh frit and process the waste through the HWVP.

  19. Post-eruptive alteration of silicic ignimbrites and lavas, Gran Canaria, Canary Islands: Strontium, neodymium, lead, and oxygen isotopic evidence

    SciTech Connect

    Cousens, B.L. ); Spera, F.J. ); Dobson, P.F. )

    1993-02-01

    Isotopic analyses of Miocene comenditic, pantelleritic, and trachyphonolitic ignimbrites and lavas from Gran Canaria, Canary Islands, provide evidence for posteruptive mobility of Rb, Sr, and O. Calculated initial [sup 87]Sr/[sup 86]Sr ratios in whole-rock samples from basaltic lavas and feldspar mineral separates from ignimbrites define a magmatic trend in the stratigraphic section, from ratios of 0.70340 at the base of the Mogan Formation to 0.70305 in the lower Fataga Formation. However, calculated apparent initial [sup 87]Sr/[sup 86]Sr ratios in hydrated vitrophyre and devitrified matrix separates range from 0.7035 to 0.7090. [delta][sup 18]O ratios in basalts and feldspars vary little, from +5.7 to +6.1, yet range from +6.5 to +15.0 in the ignimbrite matrices. In contrast to the Sr and O isotope ratios, Pb and Nd isotope ratios are identical within analytical error in feldspars and their silicic ignimbrite matrices. Sequential leaching experiments and the oxygen data suggest that low-temperature, posteruptive interaction with meteoric water, perhaps containing a small seawater component, has modified Rb and Sr concentrations in the matrices, such that calculated apparent initial [sup 87]Sr/[sup 86]Sr ratios are not those of the magmas when they were erupted. Mobilization of Rb and Sr must occur significantly after eurption. Nd and Pb isotope systems appear to be unaffected by this process. Therefore, [sup 87]Sr/[sup 86]Sr ratios determined by whole rock analysis of silicic rocks from hotspot-type oceanic islands are suspect and should not be incorporated into mantle tracer studies, although analysis of phenocrysts may produce useful data. 40 refs., 5 figs., 3 tabs.

  20. Experimental evidence shows no fractionation of strontium isotopes ((87)Sr/(86)Sr) among soil, plants, and herbivores: implications for tracking wildlife and forensic science.

    PubMed

    Flockhart, D T Tyler; Kyser, T Kurt; Chipley, Don; Miller, Nathan G; Norris, D Ryan

    2015-01-01

    Strontium isotopes ((87)Sr/(86)Sr) can be useful biological markers for a wide range of forensic science applications, including wildlife tracking. However, one of the main advantages of using (87)Sr/(86)Sr values, that there is no fractionation from geological bedrock sources through the food web, also happens to be a critical assumption that has never been tested experimentally. We test this assumption by measuring (87)Sr/(86)Sr values across three trophic levels in a controlled greenhouse experiment. Adult monarch butterflies were raised on obligate larval host milkweed plants that were, in turn, grown on seven different soil types collected across Canada. We found no significant differences between (87)Sr/(86)Sr values in leachable Sr from soil minerals, organic soil, milkweed leaves, and monarch butterfly wings. Our results suggest that strontium isoscapes developed from (87)Sr/(86)Sr values in bedrock or soil may serve as a reliable biological marker in forensic science for a range of taxa and across large geographic areas.

  1. Stable strontium isotopes ( δ88/86Sr) in cold-water corals — A new proxy for reconstruction of intermediate ocean water temperatures

    NASA Astrophysics Data System (ADS)

    Rüggeberg, Andres; Fietzke, Jan; Liebetrau, Volker; Eisenhauer, Anton; Dullo, Wolf-Christian; Freiwald, André

    2008-05-01

    Zooxanthellate scleractinian corals are known as archives for temporal variations of climate variables, such as sea surface temperature, salinity or productivity. The use of azooxanthellate cold-water corals as potential archives for intermediate water mass properties and climate variability was tested recently. However, the correlation of established proxies such as δ18O and δ13C with temperature is difficult since there is no direct temperature equation applicable as in shallow-water corals. Other temperature proxies such as Sr/Ca, Mg/Ca and U/Ca are influenced by the complex microstructure of the aragonite skeleton, the rate of calcification, and other vital effects observed for coral species. For the first time we show that the stable strontium isotope ratio δ88/86Sr incorporated in the skeletons of the cold-water coral species Lophelia pertusa portrays the ambient seawater temperature. The temperature sensitivity from live samples collected along the European continental margin covering a temperature range from 6° to 10 °C is 0.026 ± 0.003‰/°C (2 σ standard error) which is a sensitivity similar to the tropical shallow-water coral record of Pavona clavata. This indicates a similar fractionation process of strontium for both, zooxanthellate and azooxanthellate corals. For coral aragonite the δ88/86Sr ratio may serve as a new paleo-temperature proxy and introduces new perspectives in paleoceanography with respect to intermediate water dynamics.

  2. STRONTIUM PRECIPITATION

    DOEpatents

    McKenzie, T.R.

    1960-09-13

    A process is given for improving the precipitation of strontium from an aqueous phosphoric-acid-containing solution with nickel or cobalt ferrocyanide by simultaneously precipitating strontium or calcium phosphate. This is accomplished by adding to the ferrocyanide-containing solution calcium or strontium nitrate in a quantity to yield a concentration of from 0.004 to 0.03 and adjusting the pH of the solution to a value of above 8.

  3. Trapping and evaporation of strontium-87 and strontium-88 mixtures

    NASA Astrophysics Data System (ADS)

    Mickelson, Pascal Gerry

    This thesis describes trapping and evaporative cooling of ultracold 87Sr and 88Sr mixtures in an optical dipole trap to produce the first Bose-Einstein condensate (BEC) of 88Sr. Furthermore, this work presents thermalization studies that characterize the scattering properties of these ultracold strontium samples. Such ultracold atomic gases have become an important area of research because of their potential for improving optical frequency standards and for realizing quantum computation using neutral atoms. A BEC of 88Sr is particularly interesting because the small value of its background s-wave scattering length may enable the use of optical Feshbach resonances to create two-dimensional solitons. However, the small scattering length for 88Sr also hinders efficient evaporative cooling in the optical dipole trap, a necessary step to producing a BEC. Experiments with other ultracold gases have successfully overcome this hurdle by mixing in a second atomic species which, by introducing stronger interactions with the weakly interacting species, enables evaporation to colder temperatures via sympathetic cooling. For this work, we use 87Sr to sympathetically cool 88Sr during forced evaporation to quantum degeneracy. Previous experiments in the Killian Lab characterized 88Sr in detail. Here, I emphasize the new or improved aspects that have allowed trapping and cooling of the mixtures of 87Sr and 88 Sr: trapping of 87Sr by itself, spectroscopic measurements of all the stable strontium isotopes to guide the trapping of isotopic mixtures, imaging of both 87Sr and 88Sr, and the various trade-offs necessary to simultaneously trap 87Sr and 88Sr. Finally, I discuss how the thermalization studies of the scattering properties of the isotopes guide the forced evaporation of mixed isotope samples. These efforts result in the production of the BEC of 88Sr, but they also point the way to future studies of fermionic quantum degeneracy in 87Sr and to the rich physics of mixed species

  4. Strontium isotope evidence for migration in late Pleistocene Rangifer: implications for Neanderthal hunting strategies at the Middle Palaeolithic site of Jonzac, France.

    PubMed

    Britton, Kate; Grimes, Vaughan; Niven, Laura; Steele, Teresa E; McPherron, Shannon; Soressi, Marie; Kelly, Tegan E; Jaubert, Jacques; Hublin, Jean-Jacques; Richards, Michael P

    2011-08-01

    In order to understand the behaviours and subsistence choices of Palaeolithic hunter-gatherers, it is essential to understand the behavioural ecology of their prey. Here, we present strontium isotope data from sequentially-sampled enamel from three reindeer (Rangifer tarandus ssp.) and a single bison (Bison cf. priscus) from the late Middle Palaeolithic site of Jonzac (Chez-Pinaud), France. The results are used to investigate the ranging and migratory behaviours of these important prey species. We found that the bison had isotope values most consistent with a local range, while the three reindeer had values indicating a seasonal migration pattern. Due to the similarity of the patterning of two of the three reindeer and in conjunction with zooarchaeological results, we suggest that they may have been from the same herd, were likely killed around the same point during their seasonal round and may therefore be the product of a single hunting event or a small number of successive hunting events. The isotope analyses complement the zooarchaeological data and have allowed greater insight into the palaeoecology of these species, the palaeoenvironment, and Neanderthal site use and hunting strategies. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Strontium isotope investigation of ungulate movement patterns on the Pleistocene Paleo-Agulhas Plain of the Greater Cape Floristic Region, South Africa

    NASA Astrophysics Data System (ADS)

    Copeland, Sandi R.; Cawthra, Hayley C.; Fisher, Erich C.; Lee-Thorp, Julia A.; Cowling, Richard M.; le Roux, Petrus J.; Hodgkins, Jamie; Marean, Curtis W.

    2016-06-01

    Middle Stone Age sites located within the Greater Cape Floristic Region on the South African southern coast have material culture with early evidence for key modern human behaviors such as projectile weaponry, large animal hunting, and symbolic behavior. In order to interpret how and why these changes evolved, it is necessary to understand their ecological context as it has direct relevance to foraging behavior. During periods of lowered sea level, a largely flat and vast expanse of land existed south of the modern coastline, but it is now submerged by higher sea levels. This exposed area, the Paleo-Agulhas Plain, likely created an ecological context unlike anything in the region today, as evidenced by fossil assemblages dominated by migratory ungulates. One hypothesis is that the Paleo-Agulhas Plain supported a migration ecosystem of large grazers driven by summer rainfall, producing palatable forage during summer in the east, and winter rainfall, producing palatable forage during winter in the west. Alternatively, ungulates may have been moving from the coastal plain in the south to the interior north of the Cape Fold Mountains, as observed for elephants in historic times. In this study, we assess ungulate movement patterns with inter- and intra-tooth enamel samples for strontium isotopes in fossil fauna from Pinnacle Point sites PP13B and PP30. To accomplish our goals we created a bioavailable 87Sr/86Sr isoscape for the region by collecting plants at 171 sampling sites and developing a geospatial model. The strontium isotope results indicate that ungulates spent most of their time on the Paleo-Agulhas Plain and avoided dissected plain, foothill, and mountain habitats located more than about 15 km north of the modern coastline. The results clearly exclude a north-south (coastal-interior) movement or migration pattern, and cannot falsify the east-west movements hypothesized in the south coast migration ecosystem hypothesis.

  6. Pure and Strontium Doped Nano Hydroxyapatite: New Approach for Bone Implant and Drug Delivery System

    NASA Astrophysics Data System (ADS)

    Tank, Kashmira P.; Vasant, Sonal R.; Chudasama, Kiran S.; Thaker, Vrinda S.; Joshi, Mihir J.

    2011-07-01

    Hydroxyapatite, (Ca10(PO4)6(OH)2-Hap), an excellent inorganic biomaterial, find various applications. The chemical composition of Hap is similar to that of the inorganic matrix of human bone and dental enamel. It is also used in drug delivery system and coating of bone implant. In the present study, pure nano Hap and Strontium doped nano-Hap (Sr-Hap) with different concentrations were synthesized by surfactant mediated approach. The samples were characterized by EDAX, XRD and TEM. The hemolytic properties were also studied and it proved that all the samples were non-hemolytic.

  7. The use of strontium-87/strontium-86 ratios to measure atmospheric transport in forested watersheds

    SciTech Connect

    Graustein, W.C.; Armstrong, R.L.

    1983-01-21

    Strontium-87/strontium-86 ratios indicate the sources of strontium in samples of natural waters, vegetation, and soil material taken from watersheds in the Sangre de Cristo Mountains of New Mexico. More than 75 percent of the strontium in the vegetation is ultimately derived from atmospheric transport and less than 25 percent from the weathering of the underlying rock. Much of the airborne strontium enters the watersheds by impacting on coniferous foliage, but deciduous foliage apparently traps little, if any, strontium-bearing aerosol. The strontium and presumably other nutrients are continuously recycled in a nearly closed system consisting of upper soil horizons, forest litter, and the standing crop of vegetation.

  8. The Use of Strontium-87/Strontium-86 Ratios to Measure Atmospheric Transport into Forested Watersheds

    NASA Astrophysics Data System (ADS)

    Graustein, William C.; Armstrong, Richard L.

    1983-01-01

    Strontium-87/strontium-86 ratios indicate the sources of strontium in samples of natural waters, vegetation, and soil material taken from watersheds in the Sangre de Cristo Mountains of New Mexico. More than 75 percent of the strontium in the vegetation is ultimately derived from atmospheric transport and less than 25 percent from the weathering of the underlying rock. Much of the airborne strontium enters the watersheds by impacting on coniferous foliage, but deciduous foliage apparently traps little, if any, strontium-bearing aerosol. The strontium and presumably other nutrients are continuously recycled in a nearly closed system consisting of upper soil horizons, forest litter, and the standing crop of vegetation.

  9. Strontium isotopes ((87) Sr/(86) Sr) in terrestrial ecological and palaeoecological research: empirical efforts and recent advances in continental-scale models.

    PubMed

    Crowley, Brooke E; Miller, Joshua H; Bataille, Clément P

    2017-02-01

    Strontium (Sr) isotope analysis can provide detailed biogeographical and ecological information about modern and ancient organisms. Because Sr isotope ratios ((87) Sr/(86) Sr) in biologically relevant materials such as water, soil, vegetation, and animal tissues predominantly reflect local geology, they can be used to distinguish geologically distinct regions as well as identify highly mobile individuals or populations. While the application of Sr isotope analysis to biological research has been steadily increasing, high analytical costs have prohibited more widespread use. Additionally, accessibility of this geochemical tool has been hampered due to limited understanding of (i) the degree to which biologically relevant materials differ in their spatial averaging of (87) Sr/(86) Sr ratios, and (ii) how these differences may be affected by lithologic complexity. A recently developed continental-scale model that accounts for variability in bedrock weathering rates and predicts Sr isotope ratios of surface water could help resolve these questions. In addition, if this 'local water' model can accurately predict (87) Sr/(86) Sr ratios for other biologically relevant materials, there would be reduced need for researchers to assess regional Sr isotope patterns empirically. Here, we compile (87) Sr/(86) Sr data for surface water, soil, vegetation, and mammalian and fish skeletal tissues from the literature and compare the accuracy with which the local water model predicts Sr isotope data among these five materials across the contiguous USA. We find that measured Sr isotope ratios for all five materials are generally close to those predicted by the local water model, although not with uniform accuracy. Mammal skeletal tissues are most accurately predicted, particularly in regions with low variability in (87) Sr/(86) Sr predicted by the local water model. Increasing regional geologic heterogeneity increases both the offset and variance between modelled and empirical Sr

  10. Degenerate gases of strontium for studies of quantum magnetism

    NASA Astrophysics Data System (ADS)

    Barker, Daniel Schaeder

    We describe the construction and characterization of a new apparatus that can produce degenerate quantum gases of strontium. The realization of degenerate gases is an important first step toward future studies of quantum magnetism. Three of the four stable isotopes of strontium have been cooled into the degenerate regime. The experiment can make nearly pure Bose-Einstein condensates containing approximately 1x104 atoms, for strontium-86, and approximately 4x105 atoms, for strontium-84. We have also created degenerate Fermi gases of strontium-87 with a reduced temperature, T/TF of approximately 0.2. The apparatus will be able to produce Bose-Einstein condensates of strontium-88 with straightforward modifications. We also report the first experimental and theoretical results from the strontium project. We have developed a technique to accelerate the continuous loading of strontium atoms into a magnetic trap. By applying a laser addressing the 3P1 to 3 S1 transition in our magneto-optical trap, the rate at which atoms populate the magnetically-trapped 3P 2 state can be increased by up to 65%. Quantum degenerate gases of atoms in the metastable 3P0 and 3P2 states are a promising platform for quantum simulation of systems with long-range interactions. We have performed an initial numerical study of a method to transfer the ground state degenerate gases that we can currently produce into one of the metastable states via a three-photon transition. Numerical simulations of the Optical Bloch equations governing the three-photon transition indicate that >90% of a ground state degenerate gas can be transferred into a metastable state.

  11. Stable Strontium (δ88/86Sr) and U-Th isotope systematics of cold-water corals: A combined proxy for Holocene changes of the Mediterranean outflow

    NASA Astrophysics Data System (ADS)

    Liebetrau, V.; Rüggeberg, A.; Fietzke, J.; Eisenhauer, A.; Flögel, S.; Linke, P.; Schönfeld, J.

    2007-12-01

    The application of δ18O and Sr/Ca for temperature reconstruction on cold water corals has been shown to be restricted. Hence, the development and application of alternative proxies is highly desirable. This study combines the stable strontium isotope method (δ88/86Sr, Fietzke and Eisenhauer (2006)) as a potential paleotemperature proxy with MIC-ICP-MS (multi ion counting - inductively coupled plasma - mass spectrometry) U-Th geochronolgy on cold-water corals from the central Gulf of Cadiz. The sampled reef structure in 1325 m depth on top of the Captain Arutyunov Mud Volcano (MV) consists predominantly of dead Lophelia pertusa, accompanied rarely by living solitary corals ( Dendrophyllia sp.). Potentially recorded environmental influences on these archives are significant water mass changes, e.g. variation of depth and intensity of the Mediterranean Outflow Water (MOW) due to climate changes, time intervals of marine methane emanation (surface-near gas-hydrate occurre close to the coral site) and the mud volcano activity itself. Assuming a temperature dependent strontium isotope fractionation during calcium carbonate precipitation temperatures were determined for the living solitary corals, ranging from 9 to 11.5 ° C (typical error: about 1 ° C). During sampling the bottom water temperature was 8.96 ° C and the lower MOW reached from 1075 to 1188 m depth with 10 to 10.5 ° C. First U-Th age data reflect slow growth rates of 0.13 to 0.25 mm/year for the solitary corals. However, the temperature correlation implies the stable strontium approach, which was originally deduced from reef building corals, as suitable for solitary species as well. For the fossil Lophelia pertusa colonies the actual δ88/86Sr data set indicates a range from 7.5 to 13 ° C with a distinct U-Th age distribution over the last 10 ka, closely correlating with the water depth specific record of lower MOW published by Schönfeld and Zahn (2000). The implication of a lower MOW control on reef

  12. Laser system for isotope separation

    NASA Astrophysics Data System (ADS)

    Shirayama, Shimpey; Mikatsura, Takefumi; Ueda, Hiroaki; Konagai, Chikara

    1990-06-01

    Atomic vapor laser isotope separation (AVLIS) is regarded as the most promising method to obtain srightly enriched economical nuclear fuel for a nuclear power plant. However, achieving a high power laser seems to be the bottle neck in its industrialization. In 1985, after successful development of high power lasers, the U.S. announced that AVLIS would be used for future methods of uranium enrichment. In Japan , Laser Atomic Separation Enrichment Research Associates of Japan (LASER-J), a joint Japanese utility companies research organization, was founded in April, 1987, to push a development program for laser uranium enrichment. Based on research results obtained from Japanese National Labs, and Universities , Laser-J is now constructing an AVLIS experimental facility at Tokai-mura. It is planned to have a 1-ton swu capacity per year in 1991. Previous to the experimental facility construction , Toshiba proceeded with the preliminary testing of an isotope separation system, under contract with Laser-J. Since the copper vapor laser (CVL) and the dye laser (DL) form a good combination , which can obtain high power tunable visible lights ,it is suitable to resonate uranium atoms. The laser system was built and was successfully operated in Toshiba for two years. The system consist of three copper vapor lasers , three dye lasers and appropriate o Atomic vapor laser isotope separation (AVLIS) is regarded as the most promising method to obtain srightly enriched economical nuclear fuel for a nuclear power plant. However, achieving a high power laser seems to be the bottle neck in its industrialization. In 1985, after successful development of high power lasers, the U.S. announced that AVLIS would be used for future methods of uranium enrichment. In Japan , Laser Atomic Separation Enrichment Research Associates of Japan (LASER-J) , a joint Japanese utility companies research organization , was founded in April, 1987, to push a development program for laser uranium enrichment

  13. STRONTIUM & TRANSURANIC (TRU) SEPARATION PROCESS IN THE DOUBLE SHELL TANK (DST) SYSTEM

    SciTech Connect

    JOHNSON; SWANSON; BOECHLER

    2005-06-10

    The supernatants stored in tanks 241-AN-102 (AN-102) and 241-AN-107 (AN-107) contain soluble strontium-90 ({sup 90}Sr) and transuranic (TRU) elements that require removal prior to vitrification to comply with the Waste Treatment and Immobilization Plant (WTP) immobilized low-activity waste (ILAW) specification and with the 1997 agreement with the Nuclear Regulatory Commission on incidental waste. A precipitation process has been developed and tested with tank waste samples and simulants using strontium nitrate (Sr(NO{sub 3}){sub 2}) and sodium permanganate (NaMnO{sub 4}) to separate {sup 90}Sr and TRU from these wastes. This report evaluates removing Sr/TRU from AN-102 and AN-107 supernates in the DST system before delivery to the WTP. The in-tank precipitation is a direct alternative to the baseline WTP process, using the same chemical separations. Implementing the Sr/TRU separation in the DST system beginning in 2012 provides {approx}6 month schedule advantage to the overall mission, without impacting the mission end date or planned SST retrievals.

  14. Natural uranium and strontium isotope tracers of water sources and surface water-groundwater interactions in arid wetlands: Pahranagat Valley, Nevada, USA

    USGS Publications Warehouse

    Paces, James B.; Wurster, Frederic C.

    2014-01-01

    Near-surface physical and chemical process can strongly affect dissolved-ion concentrations and stable isotope compositions of water in wetland settings, especially under arid climate conditions. In contrast, heavy radiogenic isotopes of strontium (87Sr/86Sr) and uranium (234U/238U) remain largely unaffected and can be used to help identify unique signatures from different sources and quantify end-member mixing that would otherwise be difficult to determine. The utility of combined Sr and U isotopes are demonstrated in this study of wetland habitats on the Pahranagat National Wildlife Refuge, which depend on supply from large-volume springs north of the Refuge, and from small-volume springs and seeps within the Refuge. Water budgets from these sources have not been quantified previously. Evaporation, transpiration, seasonally variable surface flow, and water management practices complicate the use of conventional methods for determining source contributions and mixing relations. In contrast, 87Sr/86Sr and 234U/238U remain unfractionated under these conditions, and compositions at a given site remain constant. Differences in Sr- and U-isotopic signatures between individual sites can be related by simple two- or three-component mixing models. Results indicate that surface flow constituting the Refuge’s irrigation source consists of a 65:25:10 mixture of water from two distinct regionally sourced carbonate aquifer springs, and groundwater from locally sourced volcanic aquifers. Within the Refuge, contributions from the irrigation source and local groundwater are readily determined and depend on proximity to those sources as well as water management practices.

  15. Investigating the sources of the labile fraction in sediments from silicate-drained rocks using trace elements, and strontium and lead isotopes.

    PubMed

    Négrel, Philippe; Roy, Stéphane

    2002-10-21

    Elemental concentrations of the trace elements Rb, Sr, Th, Pb, Zn, Cu, Ni, Cd and Sb, as well as Sr and Pb isotopic compositions, were determined on the labile fraction (called acid-extracted matter AEM, Négrel et al., Chem. Geol. 166 (2000) 271-85) of soil and sediment along two small rivers located in the centre of France, one flowing from basalt, the other one on granite-gneiss. Oxide-mineral form in AEM (i.e. Fe-Mn oxides), acts as the main carrier phase. Analysis of the relationships between the trace elements, and lead and strontium isotopes allows the origin of the elements (i.e. natural and anthropogenic) and their history, both in the sediment and soil from the small watersheds to be assessed. Lead-isotope compositions in AEM display large fluctuation in the two watersheds and show a large scatter between natural input (basalt and granite), atmospheric input from gasoline, and input from past mining activities. On the basaltic watershed, Pb and other trace elements like Sb deriving from past mining waste are mainly related to atmospheric origin, while on the granitic terrain Pb originates from mineralization. The Sr-isotope compositions of AEM, water and residues are similar in the watershed draining basalt. On the watershed draining granite, AEM and streamwater shows 87Sr/86Sr ratios similar in the upstream part of the watershed and a divergence between the two ratios appears in the downstream part of the watershed implying that oxides have precipitated upstream and are not re-equilibrated during their transport downstream.

  16. Natural uranium and strontium isotope tracers of water sources and surface water-groundwater interactions in arid wetlands - Pahranagat Valley, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Paces, James B.; Wurster, Frederic C.

    2014-09-01

    Near-surface physical and chemical process can strongly affect dissolved-ion concentrations and stable-isotope compositions of water in wetland settings, especially under arid climate conditions. In contrast, heavy radiogenic isotopes of strontium (87Sr/86Sr) and uranium (234U/238U) remain largely unaffected and can be used to help identify unique signatures from different sources and quantify end-member mixing that would otherwise be difficult to determine. The utility of combined Sr and U isotopes are demonstrated in this study of wetland habitats on the Pahranagat National Wildlife Refuge, which depend on supply from large-volume springs north of the Refuge, and from small-volume springs and seeps within the Refuge. Water budgets from these sources have not been quantified previously. Evaporation, transpiration, seasonally variable surface flow, and water management practices complicate the use of conventional methods for determining source contributions and mixing relations. In contrast, 87Sr/86Sr and 234U/238U remain unfractionated under these conditions, and compositions at a given site remain constant. Differences in Sr- and U-isotopic signatures between individual sites can be related by simple two- or three-component mixing models. Results indicate that surface flow constituting the Refuge's irrigation source consists of a 65:25:10 mixture of water from two distinct regionally sourced carbonate-aquifer springs, and groundwater from locally sourced volcanic aquifers. Within the Refuge, contributions from the irrigation source and local groundwater are readily determined and depend on proximity to those sources as well as water management practices.

  17. Soil properties, strontium isotopic signatures and multi-element profiles to authenticate the origin of vegetables from small-scale regions: illustration with early potatoes from southern Italy.

    PubMed

    Zampella, Mariavittoria; Quétel, Christophe R; Paredes, Eduardo; Goitom Asfaha, Daniel; Vingiani, Simona; Adamo, Paola

    2011-10-15

    We propose a method for the authentication of the origin of vegetables grown under similar weather conditions, in sites less than 10 km distance from the sea and distributed over a rather small scale area (58651 km(2)). We studied how the strontium (Sr) isotopic signature and selected elemental concentrations ([Mn], [Cu], [Zn], [Rb], [Sr] and [Cd]) in early potatoes from three neighbouring administrative regions in the south of Italy were related to the geological substrate (alluvial sediments, volcanic substrates and carbonate rocks) and to selected soil chemical properties influencing the bioavailability of elements in soils (pH, cation exchange capacity and total carbonate content). Through multiple-step multivariate statistics (PLS-DA) we could assign 26 potatoes (including two already commercialised samples) to their respective eight sites of production, corresponding to the first two types of geological substrates. The other 12 potatoes from four sites of production had similar characteristics in terms of the geological substrate (third type) and these soil properties could be grouped together. In this case, more discriminative parameters would be required to allow the differentiation between sites. The validation of our models included external prediction tests with data of potatoes harvested the year before and a study on the robustness of the uncertainties of the measurement results. Annual variations between multi-elemental and Sr isotopic fingerprints were observed in potatoes harvested from soils overlying carbonate rocks, stressing the importance of testing long term variations in authentication studies.

  18. Rubidium-strontium, uranium, and thorium-lead dating of lunar material.

    PubMed

    Gopalan, K; Kaushal, S; Lee-Hu, C; Wetherill, G W

    1970-01-30

    Rubidiuom and stronztiulm concentrations and strontium isotopic compositions have been measutred on whole rock samples and density fractions of microgabbro. Density fractionis on two rocks define isochrons of 3400 and 4500 million years with large uincertainties owing to low enrichment of radiogenic strontium. Lead from fine surface material is highly radiogenic. An age of 4750 million years has been calculated from the ratio of (207)Pb/(206)Pb. The concentrations of uiranium, thorium, and lead isotopes are consistent with the evolution of lead in a 4700-million-year-old closed system characterized by the ratios of uranium to lead and of thoriunm to lead in this sutrface material.

  19. Strontium and Barium Isotopes in Type X Presolar Silicon Carbide Grains Analyzed with CHILI — Two Types of Supernova Grains

    NASA Astrophysics Data System (ADS)

    Stephan, T.; Trappitsch, R.; Davis, A. M.; Gyngard, F.; Hoppe, P.; Pellin, M. J.

    2016-08-01

    Using the Chicago Instrument for Laser Ionization, we have measured Sr and Ba isotopes in 10 presolar SiC grains, including 3 X grains. One grain is X1, the other two are X2 grains. Both X grain types show distinct properties in Sr and Ba isotopes.

  20. Strontium isotope composition of skeletal material can determine the birth place and geographic mobility of humans and animals.

    PubMed

    Beard, B L; Johnson, C M

    2000-09-01

    The Sr isotope composition measured in skeletal elements (e.g., bone, teeth, or antlers) can be used to infer the geographic region that an animal or human inhabited, because different regions tend to have distinct Sr isotope compositions, and natural variations in the relative abundance of Sr isotopes are not changed as Sr is processed through the food chain. Therefore, an organism that ingests Sr from one region can have a Sr isotope composition that is different than that of an organism that ingests Sr from another region. The Sr isotope composition of skeletal elements is a reflection of the concentration-weighted average of dietary Sr that was ingested while that skeletal element was produced. Because different skeletal elements grow and exchange Sr at different stages during the life times of organisms, Sr isotope analysis of different skeletal elements can be used to infer changes in geographic location at different stages in an organism's life. The Sr isotope composition measured in human teeth will reflect the average Sr isotope composition that was ingested as a child, due to the immobile nature of Sr and Ca in teeth after formation, whereas the Sr isotope composition of bone will reflect the average isotopic composition over the last ten years of life, due to continuous biological processing of Sr and Ca in bone. Inferring the average isotopic composition of dietary Sr is best done by analyzing skeletal fragments from control groups, which might be animals that have the same feeding habits as the animal in question, or, in the case of humans, analysis of close family relatives. In cases where it is not possible to construct a Sr isotope database from control groups, it becomes necessary to estimate the isotopic composition of dietary Sr based on geologic principles. We present three case studies from our research that illustrate a range of approaches: (1) results from a criminal case where a deer was illegally harvested and the location of the deer was

  1. Coupling Strontium Isotope and Trace Metal Geochemistry With a Watershed Flow Path Model in the Lamprey River Watershed, New Hampshire

    NASA Astrophysics Data System (ADS)

    Smith, M. A.; Bryce, J.; Davis, J.

    2007-12-01

    One significant challenge in watershed characterization is accounting for the groundwater flow system. In temperate climates, the hydrologic cycle is dominated by surface processes such as precipitation, evapotranspiration, and shallow groundwater flow. While, volumetrically, groundwater flow is less significant, it remains critically important for maintaining instream flow and closing the water budget within the watershed. The objective of the current study is to assess the adequacy of a simple groundwater flow conceptual model to describe groundwater flow in a mesoscale (50 km2), fractured bedrock, watershed. We hypothesize that groundwater flowpaths and seasonal flowrates at the scale of kilometers can be adequately described by a highly-resolved (30 meter grid), topographically dominated, homogeneous isotropic system. To test this hypothesis, we utilize the distinct and traceable chemical and isotopic signatures of the host bedrock. The combined use of trace elements and radiogenic isotopes (e.g., 87Sr/86Sr) provides great promise for the delineation of groundwater flow paths at the watershed scale, especially when bedrock hosts have distinctive compositions. The Lamprey River, located in Southern New Hampshire, is an especially promising watershed to carry out these types of analyses because groundwater within the watershed is stored primarily in bedrock aquifers with two geochemically contrasting bedrock hosts lying adjacent to each other. The bedrock aquifers include the White Mountain Magmatic Series of Mt. Pawtuckaway, a local topographic feature, and the Massabesic Gneiss Complex. Bedrock measurements, as well as rock leachate solutions, show distinct signatures. Surface water samples collected from ponds underlain by the differing hosts also reflect the bedrock signals with 87Sr/86Sr ranging from 0.70686 in the White Mountain Magmatic Series to 0.71443 in the Massabesic Gneiss Complex. Surface water samples collected along the Lamprey River during Summer

  2. Strontium-isotope stratigraphy of Upper Cretaceous rudist bivalves: Biozones, evolutionary patterns and sea-level change calibrated to numerical ages

    NASA Astrophysics Data System (ADS)

    Steuber, Thomas; Schlüter, Malte

    2012-08-01

    Numerical ages derived from strontium-isotope stratigraphy of 81 Late Turonian-Maastrichtian rudist localities from the Caribbean to Oman are used to establish stratigraphical ranges of readily identifiable taxa of rudist bivalves (Hippuritida). Based on these ranges, seven biozones for the Turonian-Maastrichtian of the central-eastern Mediterranean Tethys, and three biozones for the mid-Campanian-Maastrichtian of the Arabian Plate are established. Most of these are interval zones, each based on the first stratigraphical appearance of the nominal taxon. Micro-evolutionary patterns such as phyletic size increase have been demonstrated for some of the nominal species, as well as a trend of stratigraphical range expansion from the Turonian to the Maastrichtian. Implications of the geochronology of Late Cretaceous carbonate platforms for the biostratigraphy of other benthic fossils are briefly discussed. Three significant gaps in the stratigraphical distribution of rudist localities in the lower, middle, and uppermost Campanian, respectively, correlate with other records of sea-level change, indicating that they correspond to major eustatic sea-level falls. Only a limited number of rudist taxa is evaluated here, but the early and latest Campanian sea-level falls correspond to faunal turnover and extinction of characteristic associations of Late Cretaceous Hippuritida. The final extinction of the Hippuritida at the Cretaceous/Paleogene boundary is evaluated based on the available numerical ages of eighteen Late Maastrichtian localities. Eighteen genera are recorded at the six youngest localities, which thus have a species richness similar to older Late Cretaceous localities. While the ultimate cause for extinction of the Hippuritida must be evaluated on time scales beyond the resolution of strontium-isotope stratigraphy, the data set evaluated provides some insight into the pattern of their demise, which is considered to be the result of a high degree of endemism

  3. Carbon, oxygen, and strontium isotopic composition of methane-derived authigenic carbonates in methane seep areas, eastern margin of Japan Sea

    NASA Astrophysics Data System (ADS)

    Kakizaki, Y.; Ishikawa, T.; Hiruta, A.; Matsumoto, R.

    2016-12-01

    We report the occurrence, mineralogy, and isotopic composition (δ13C; δ18O) of methane-derived authigenic carbonates (MDACs) from three methane seep areas with shallow gas hydrate (Umitaka Spur, Joetsu Knoll, and off-Tobishima Island), in the southeastern margin of Japan Sea. Furthermore, we present strontium isotopic ratios (87Sr/86Sr) of MDACs, pore waters, and seawater from Umitaka Spur. MDACs range from a few mm to several tens of cm in diameter. Their shape is quite varied, e.g. nodular, platy, and indetermine form. Most MDACs are composed of high-Mg calcite. The δ13C values of MDACs from Umitaka Spur range from -30 to -4 permil. These isotopic values are higher than those of Joetsu Knoll and off-Tobishima Island. This difference is dependent upon the formation depth of MDACs in the sediment column. It probably indicates a difference in the formation environment of MDACs (e.g. methane flux). Meanwhile, range of the δ18O values of MDACs from those three areas is mostly equal. The 87Sr/86Sr ratios in MDACs from shallow sediment depth of Umitaka Spur are equal to those of modern surface seawater just above Umitaka Spur. The 87Sr/86Sr ratios of MDACs from deeper sediment depth are lower, and the Sr-isotopic trend indicates an upward increase. This trend can be correlated to the global Sr-isotopic trend of the seawater from late Pleistocene to present. It means that 87Sr/86Sr ratios of MDACs reflect the 87Sr/86Sr ratio of seawater at the formation age. However, the 87Sr/86Sr ratios in pore water are lower than those of MDACs, yet follow a parallel trend. This would suggest that the pore water includes a source of light Sr, presumably released from tuff and volcaniclastics during diagenetic processes. This study was conducted under the commission from AIST as a part of the methane hydrate research project funded by METI (the Ministry of Economy, Trade and Industry, Japan).

  4. Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems

    SciTech Connect

    Nimz, G. J., LLNL

    1998-06-01

    A variety of physical processes affect solute concentrations within catchment waters. The isotopic compositions of the solutes can indicate which processes have determined the observed concentrations. These processes together constitute the physical history of the water. Many solutes in natural waters are derived from the interaction between the water and the rock and/or soil within the system - these are termed `lithogenic` solutes. The isotopic compositions of these solutes provide information regarding rock-water interactions. Many other solutes have their isotopic compositions determined both within and outside of the catchment - i.e., in addition to being derived from catchment rock and soil, they are solutes that are also transported into the catchment. Important members of this group include solutes that have isotopic compositions produced by atomic particle interactions with other nuclides. The source of the atomic particles can be cosmic radiation (producing `cosmogenic` nuclides in the atmosphere and land surface), anthropogenic nuclear reactions (producing `thermonuclear` nuclides), or radioactive and fission decay of naturally-occurring elements, principally {sup 238}U (producing `in-situ` lithogenic nuclides in the deep subsurface). Current language usage often combines all of the atomic particle-produced nuclides under the heading `cosmogenic nuclides`, and for simplicity we will often follow that usage here, although always indicating which variety is being discussed. This paper addresses the processes that affect the lithogenic and cosmogenic solute concentrations in catchment waters, and how the isotopic compositions of the solutes can be used in integrative ways to identify these processes, thereby revealing the physical history of the water within a catchment system. The concept of a `system` is important in catchment hydrology. A catchment is the smallest landscape unit that can both participate in all of the aspects of the hydrologic cycle and

  5. Post-eruptive alteration of silicic ignimbrites and lavas, Gran Canaria, Canary Islands - Strontium, neodymium, lead, and oxygen isotopic evidence

    NASA Technical Reports Server (NTRS)

    Cousens, Brian L.; Spera, Frank J.; Dobson, Patrick F.

    1993-01-01

    The isotopic composition of lavas from oceanic islands provides important information about the composition and evolution of the earth's mantle. Isotopic analyses of Miocene comenditic, pantelleritic, and trachyphonolitic ignimbrites and lavas from the Canary islands were performed. Results provide evidence for posteruptive mobility of Rb and Sr during low temperature postemplacement interaction with circulating ground water. Calculated Sr isotope ratios define a magmatic trend in the stratigraph section. 87Sr/86Sr ratios in hydrated vitrophyte and devitrified matrix separates indicate significant posteruptive interaction with meteoric water starting soon after deposition. This process extends patchily through the entire pyroclastic flow and may be ongoing. 87Sr/86Sr ratios determined by whole rock analysis of silicic rocks from oceanic islands are suspect and should not be incorporated into mantle tracer studies. Anorthoclase phenocrysts are resistant to these processes and may produce useful data.

  6. Unusual diagenetic alteration of volcanoclastic sediments in the Tonga fore-are: Evidence from chemical and strontium isotopic compositions of interstitial waters

    NASA Astrophysics Data System (ADS)

    Blanc, Gérard; Vitali, Frédéric; Stille, Peter

    1995-11-01

    The depth variations in the major chemical components dissolved in interstitial waters from the Tonga margin (ODP Site 841) are much more pronounced than those usually observed in deep-sea sediments. The extensive alteration of volcanic Miocene sediments to secondary minerals such as analcime, clays, and thaumasite forms a CaCl 2-rich brine. The brine results from a high exchange of Ca to Na, K, and Mg and an increase in Cl concentrations due to removal of H 2O from the fluid during the authigenesis of hydrous minerals. The formation of thaumasite could have partly controlled the concentration of dissolved SO 4, HCO 3, and Ca in the Miocene sediments. The strontium isotopic signature of the interstitial water suggests that alteration of the volcanic Miocene sediments occurred a long time after sedimentation. A transient diffusion model indicates that molecular diffusion was not prevented by lithologic barriers and that the formation of secondary minerals in the Miocene sediment occurred over a short period of time (e.g.,≤1,000 years). The extensive diagenetic processes in the Tonga margin were mostly caused by the recent intrusion of andesite sills and dikes into the Miocene sediments.

  7. High-Throughput Method for Strontium Isotope Analysis by Multi-Collector-Inductively Coupled Plasma-Mass Spectrometer

    SciTech Connect

    Hakala, Jacqueline Alexandra

    2016-11-22

    This technical report presents the details of the Sr column configuration and the high-throughput Sr separation protocol. Data showing the performance of the method as well as the best practices for optimizing Sr isotope analysis by MC-ICP-MS is presented. Lastly, this report offers tools for data handling and data reduction of Sr isotope results from the Thermo Scientific Neptune software to assist in data quality assurance, which help avoid issues of data glut associated with high sample throughput rapid analysis.

  8. High-Throughput Method for Strontium Isotope Analysis by Multi-Collector-Inductively Coupled Plasma-Mass Spectrometer

    SciTech Connect

    Wall, Andrew J.; Capo, Rosemary C.; Stewart, Brian W.; Phan, Thai T.; Jain, Jinesh C.; Hakala, Alexandra; Guthrie, George D.

    2016-09-22

    This technical report presents the details of the Sr column configuration and the high-throughput Sr separation protocol. Data showing the performance of the method as well as the best practices for optimizing Sr isotope analysis by MC-ICP-MS is presented. Lastly, this report offers tools for data handling and data reduction of Sr isotope results from the Thermo Scientific Neptune software to assist in data quality assurance, which help avoid issues of data glut associated with high sample throughput rapid analysis.

  9. Strontium isotopes as tracers of water-rocks interactions, mixing processes and residence time indicator of groundwater within the granite-carbonate coastal aquifer of Bonifacio (Corsica, France).

    PubMed

    Santoni, S; Huneau, F; Garel, E; Aquilina, L; Vergnaud-Ayraud, V; Labasque, T; Celle-Jeanton, H

    2016-12-15

    This study aims at identifying the water-rock interactions and mixing rates within a complex granite-carbonate coastal aquifer under high touristic pressure. Investigations have been carried out within the coastal aquifer of Bonifacio (southern Corsica, France) mainly composed of continental granitic weathering products and marine calcarenite sediments filling a granitic depression. A multi-tracer approach combining physico-chemical parameters, major ions, selected trace elements, stable isotopes of the water molecule and (87)Sr/(86)Sr ratios measurements is undertaken for 20 groundwater samples during the low water period in November 2014. 5 rock samples of the sedimentary deposits and surrounding granites are also analysed. First, the water-rock interactions processes governing the groundwater mineralization are described in order to fix the hydrogeochemical background. Secondly, the flow conditions are refined through the quantification of inter aquifer levels mixing, and thirdly, the kinetics of water-rock interaction based on groundwater residence time from a previous study using CFCs and SF6 are quantified for the two main flow lines. A regional contrast in the groundwater recharge altitude allowed the oxygene-18 to be useful combined with the (87)Sr/(86)Sr ratios to differentiate the groundwater origins and to compute the mixing rates, revealing the real extension of the watershed and the availability of the resource. The results also highlight a very good correlation between the groundwater residence time and the spatial evolution of (87)Sr/(86)Sr ratios, allowing water-rock interaction kinetics to be defined empirically for the two main flow lines through the calcarenites. These results demonstrate the efficiency of strontium isotopes as tracers of water-rock interaction kinetics and by extension their relevance as a proxy of groundwater residence time, fundamental parameter documenting the long term sustainability of the hydrosystem. Copyright © 2016

  10. Provenancing of unidentified World War II casualties: Application of strontium and oxygen isotope analysis in tooth enamel.

    PubMed

    Font, Laura; Jonker, Geert; van Aalderen, Patric A; Schiltmans, Els F; Davies, Gareth R

    2015-01-01

    In 2010 and 2012 two sets of unidentified human remains of two World War II soldiers were recovered in the area where the 1944-1945 Kapelsche Veer bridgehead battle took place in The Netherlands. Soldiers of four Allied nations: British Royal Marine Commandos, Free Norwegian Commandos, Free Poles and Canadians, fought against the German Army in this battle. The identification of these two casualties could not be achieved using dental record information of DNA analysis. The dental records of Missing in Action soldiers of the Allied nations did not match with the dental records of the two casualties. A DNA profile was determined for the casualty found in 2010, but no match was found. Due to the lack of information on the identification of the casualties provided by routine methods, an isotope study was conducted in teeth from the soldiers to constrain their provenance. The isotope study concluded that the tooth enamel isotope composition for both casualties matched with an origin from the United Kingdom. For one of the casualties a probable origin from the United Kingdom was confirmed, after the isotope study was conducted, by the recognition of a characteristic belt buckle derived from a Royal Marine money belt, only issued to British Royal Marines, found with the remains of the soldier. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Neodymium and strontium isotopic study of Australasian tektites - New constraints on the provenance and age of target materials

    NASA Technical Reports Server (NTRS)

    Blum, Joel D.; Papanastassiou, D. A.; Wasserburg, G. J.; Koeberl, C.

    1992-01-01

    The Nd and Sr isotopic compositions of Australasian tectites (including two flanged Australian tectites, two low-SiO2 Muong Nong-type tectites, and three high-SiO2 Muong Nong-type tectites) and the Nd, Sm, Sr, and Rb concentrations were investigated by isotope-dilution thermal ionization mass spectrometry, and the Sm-Nd and Rb-Sr isotope systematics were used to study the characteristics of the parental material. It is shown that the Nd and Sr isotopic data provide evidence that all Australasian tektites were derived from a single sedimentary formation with a narrow range of stratigraphic ages close to 170 Ma. It is suggested that all of the Australasian tektites were derived from a single impact event and that the australites represent the upper part of a melt sheet ejected at high velocity, whereas the indochinites represent melts formed at a lower level in the target material distributed closer to the area of the impact.

  12. Suspected limited mobility of a Middle Pleistocene woman from Southern Italy: strontium isotopes of a human deciduous tooth.

    PubMed

    Lugli, Federico; Cipriani, Anna; Arnaud, Julie; Arzarello, Marta; Peretto, Carlo; Benazzi, Stefano

    2017-08-17

    We present the Sr isotopic composition of enamel of the most ancient deciduous tooth ever discovered in Italy to assess human mobility in Middle Pleistocene. Reconstructing ancient mobility is crucial for understanding human strategy at exploiting temporally and spatially patchy resources, with most studies focusing on indirect evidences, ultimately affecting our interpretation on hominin territoriality and energetic costs invested by hominin groups. Here, we use the high spatial resolution and micro-destructivity options offered by the Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry technique, to determine the (87)Sr/ (86)Sr intra-tooth variability of a human deciduous incisor from the Middle Pleistocene layers of the Isernia La Pineta site (Italy). We compared these data with the Sr isotopic signature of local micro-mammals, the broadest home-range of the macro-mammals and with modern plant samples. Our study reveals that while macro-mammals have possibly migrated through the landscape for up to 50 km, the pregnant woman from Isernia was probably local, given that the isotopic ratio of the enamel falls within the local range and is comparable with the signature of the local plants in a radius of 10 km. This is the first case study of Sr isotopic composition determination in such ancient deciduous tooth.

  13. Paleoenvironmental conditions and strontium isotope stratigraphy in the Paleogene Gafsa Basin (Tunisia) deduced from geochemical analyses of phosphatic fossils

    NASA Astrophysics Data System (ADS)

    Kocsis, László; Ounis, Anouar; Chaabani, Fredj; Salah, Neili Mohamed

    2013-06-01

    Fossil shark teeth and coprolites from three major phosphorite occurrences in the Gafsa Basin (southwestern Tunisia) were investigated for their geochemical compositions to improve local stratigraphy and to better assess paleoenvironmental conditions. 87Sr/86Sr isotope ratios of shark teeth from the Early Maastrichtian El Haria Formation and from the Early Eocene Métlaoui s.s. Formation yielded Sr isotope ages of 68 ± 1 and 47.9 ± 1.3 Ma, respectively, which accord with the expected stratigraphic positions of these sediments. Conversely, shark teeth from the Paleocene-Eocene Chouabine Formation have large variation in Sr isotope ratios even within individual layers. After statistical treatment and then elimination of certain outlier samples, three age-models are proposed and discussed. The most reasonable solution includes three subsequent Sr ages of 61.8 ± 2.2 Ma, 57.2 ± 1.8 and 54.6 ± 1.6 for layer IX, layers VIII-V and layers IV-0, respectively. Three scenarios are discussed for explanation of the presence of the outliers: (1) diagenesis, (2) re-working and (3) locally controlled seawater Sr isotope ratio. The most plausible account for the higher 87Sr/86Sr ratios relative to the global ocean in some fossils is enhanced intrabasinal re-working due to low sea level. Conversely, the sample with lower 87Sr/86Sr than the global seawater may link to diagenesis or to seawater influenced by weathering of Late Cretaceous marine carbonates, which latter is supported by model calculation as well. The ɛNd values of these fossils are very similar to those reported for Paleogene and Late Cretaceous Tethyan seawater and are compatible with the above interpretations. The relatively low oxygen isotope values in shark teeth from the topmost phosphate bed of the Chouabine Formation, together with the Sr isotope results, point toward recovering better connections with the open sea. These δ18O data reflect elevated ambient temperature, which may link to the Early Eocene

  14. Strontium isotopes test long-term zonal isolation of injected and Marcellus formation water after hydraulic fracturing.

    PubMed

    Kohl, Courtney A Kolesar; Capo, Rosemary C; Stewart, Brian W; Wall, Andrew J; Schroeder, Karl T; Hammack, Richard W; Guthrie, George D

    2014-08-19

    One concern regarding unconventional hydrocarbon production from organic-rich shale is that hydraulic fracture stimulation could create pathways that allow injected fluids and deep brines from the target formation or adjacent units to migrate upward into shallow drinking water aquifers. This study presents Sr isotope and geochemical data from a well-constrained site in Greene County, Pennsylvania, in which samples were collected before and after hydraulic fracturing of the Middle Devonian Marcellus Shale. Results spanning a 15-month period indicated no significant migration of Marcellus-derived fluids into Upper Devonian/Lower Mississippian units located 900-1200 m above the lateral Marcellus boreholes or into groundwater sampled at a spring near the site. Monitoring the Sr isotope ratio of water from legacy oil and gas wells or drinking water wells can provide a sensitive early warning of upward brine migration for many years after well stimulation.

  15. Simulating the Transfer of Strontium-90 from Soil to Leafy Vegetables by Using Strontium-88.

    PubMed

    Kuke, Ding; Shujuan, Liu; Yingxue, He; Dong, Yan; Fengshou, Zhang; Shuifeng, Wang; Jinghua, Guo; Wei, Zhang; Xin, Wang; Xiaoyan, Jiang

    2016-01-01

    The transfer, from soil to Chinese cabbage and spinach, of radioactive strontium-90 released as a result of accidents in nuclear power stations was studied using a stable isotope of strontium, namely nuclide strontium-88 ((88)Sr). The study led to an experimental model for assessing the hazard of radionuclide strontium-90 ((90)Sr) entering the food chain and for predicting the risk to food safety. Chinese cabbage and spinach were grown in pots in a greenhouse and irrigated with deionized water containing known quantities of strontium. Based on the strontium content of that water, the plants were divided into five groups (treatments) and strontium content of the soil, and 30-day-old plants were determined by inductively coupled plasma atomic emission spectroscopy instrument (ICP-AES). Data on the strontium content of soil and plants enabled the development of a model using MATLAB, a mathematical software package, which included curve fitting and problem solving using regression equations and differential equations. Although strontium curves for leaves, stems, and roots of Chinese cabbage were not exactly the same, all showed a non-linear increase when compared with the increase in the content of strontium in soil. Strontium curves for leaves, stems, and roots of spinach were very similar and showed an initial increase followed by a decrease. Strontium concentrations in both Chinese cabbage and spinach were initially related to the concentrations of sodium and sulfur, the next two relevant nuclides being calcium and magnesium. The relationship between calcium and strontium in Chinese cabbage was different from that in spinach. By using (88)Sr to simulate the transfer of radionuclide (90)Sr from soil to a crop, the relevant data required to deal with accidental release of strontium can be obtained using a fitting curve and regression equations, thereby providing some experimental basis for evaluating the potential hazards posed by such accidents to the food chain.

  16. Strontium isotopes in Melanopsis sp. as indicators of variation in hydrology and climate in the Upper Jordan Valley during the Early-Middle Pleistocene, and wider implications.

    PubMed

    Spiro, Baruch; Ashkenazi, Shoshana; Starinsky, Abraham; Katz, Amitai

    2011-04-01

    Aquifers dominated by Pleistocene basalts and Jurassic to Cretaceous calcareous rocks feed the Hula basin which is drained by the Jordan River into Lake Kinneret. The sedimentary sequence of Lower-Middle Pleistocene Benot Ya'akov Formation (BYF) exposed by excavations of the 0.78 Ma lake-side site of Gesher Benot Ya'aqov (GBY) consists of six cycles representing ca. 100 ka history of the Hula basin. This study characterizes the types of water sources in the catchment, tests the use of the Strontium (Sr) isotopes in the common extant snail Melanopsis sp. as a tracer for water in its habitat, and uses this tracer in the fossil specimens from GBY to investigate the palaeohydrology of the Hula paleolake during the corresponding period. The Sr isotope composition ((87)Sr/(86)Sr) of extant Melanopsis shells in the Hula catchment range widely (0.7046-0.7079). These analyses define distinct groups of water sources and aquifers, while the Jordan River at the GBY site has values around 0.70685. The values for fossil Melanopsis from GBY vary along stratigraphy; they are highest around 0.70710 in Cycles 1 and 2, decrease to around 0.70685 in Cycle 3, and exhibit upward trending fluctuations in the subsequent cycles to 0.70703 in Cycle 6. This trend reveals the dominance of the Hermon Jurassic aquifer during the earlier, colder periods before the Matuyama-Brunhes Boundary (MBB) and enhanced influence of the Golan basaltic aquifers, in subsequent warmer periods, indicating that the MBB coincides with climate warming as supported by other indicators. Hence, this global geochronological indicator of 0.78 Ma is also potentially a global palaeoclimatic marker. The similarity between the Sr isotope composition of the Jordan River waters and Melanopsis and those from Cycle 3 suggests that the current climate corresponds to that of the warmest period within the record of GBY, clarifying the comparative interpretation of this 100 k.yr. climate record.

  17. Strontium isotope stratigraphy of Kita-daito-jima Atoll, North Philippine Sea: implications for Neogene sea-level change and tectonic history

    NASA Astrophysics Data System (ADS)

    Ohde, S.; Elderfield, H.

    1992-11-01

    A detailed chronology of a 432 m core from Kita-daito-jima, an atoll on the Philippine Sea plate, has been obtained by strontium isotope stratigraphy. The atoll carbonate extends to late Oligocene age. The top ˜ 100 m Plio-Pleistocene section of the core has been dolomitized, and dolomite also extends to middle Miocene sediments. Sr isotopes identify two dolomitization events, at ˜ 2 and ˜ 5 Ma. Atoll growth appears to have been continuous between 18.8 and 24.3 Ma and the fit of the growth history to a standard model provides a successful confirmation of Darwin's subsidence theory. The atoll growth appears to have commenced about 42 Ma ago (6 Ma after volcanism), producing a ˜ 2 km column of atoll carbonate, in agreement with bathymetry. The subsidence model defines an apparent loss of 360 m of the sedimentary record since the early-middle Miocene boundary. The amount in excess of the ˜ 100 m associated with sea-level fall is attributed to Plio-Pleistocene uplift at rates of ˜ 20-30 m/Ma associated with the forebulge of the Philippine Sea plate prior to its subduction. Uplift rates have also been estimated using (a) the heights of dated last-interglacial coral reefs on Kita-daito-jima and nearby Minami-daito-jima (˜ 17 m/Ma and ˜ 29 m/Ma), (b) Sr isotope ages of calcites from surface samples on Minami-daito-jima (˜ 21 m/Ma) and (c) contrasts in elevation with Okino-daito-jima 100 km away (˜ 22 m/Ma). The locations of hiatuses and ages of dolomitization indicate sea-level falls of ˜ 80 m at ˜ 17-16 Ma, ˜ 30 m at ˜ 16-15 Ma, ˜ 125 m at ˜ 11 Ma, and ˜ 90 m at ˜ 5 Ma and at ˜ 2 Ma. The data have been combined with those from Enewetak Atoll to produce a curve of sea-level change for the Neogene.

  18. Strontium isotopes in peat deposits of the Sacramento-San Joaquin Delta: Records of variable sediment sources and salinity over the past ~6,700 years

    NASA Astrophysics Data System (ADS)

    Alpers, C. N.; Drexler, J. Z.; Paces, J. B.; Neymark, L. A.; Taylor, H. E.; Windham-Myers, L.; Fuller, C. C.

    2010-12-01

    Strontium (Sr) isotopes are potentially useful as an indicator of past salinity in estuarine environments because of differences between 87Sr/86Sr in seawater (Holocene value ~0.7092) and that of rivers, which vary depending on regional geology. 87Sr/86Sr values for Sr dissolved in the Sacramento River and San Joaquin River water are ~0.705 and ~0.707, respectively, based on previous work by Ingram, Hobbs, and others. Past salinity variations in the Sacramento-San Joaquin (S-SJ) Delta are of interest because current fresh-water diversions may increase salinity and affect wildlife, including threatened and endangered fish species, and it would be helpful to know if and when the Delta has been more saline. Interpretation of Sr isotopes in peat deposits in the S-SJ Delta is complicated by the occurrence of Sr in both the organic fraction of the peat (former plant material) and the inorganic fraction (trapped river sediment). Bulk chemistry and 87Sr/86Sr data were collected on cores from three S-SJ Delta sites, representing ~6,700 years of peat deposits, in two fresh (Franks Wetland, FW; and Bacon Channel Island, BACHI) and one brackish tidal marsh (Browns Island, BRI). Inorganic fraction of peat is estimated by titanium (Ti), which is inversely correlated with loss on ignition, a measure of organic content. Mean 87Sr/86Sr values for organic-rich peat intervals (Ti ≤ 0.1 wt. %) range from 0.7072 ± 0.0001 (SD, n=5) to 0.7076 ± 0.0001 (n=8) at freshwater sites (FW and BACHI, respectively) to 0.7082 ± 0.0002 (n=12) at the brackish site (BRI). At BRI, values for more inorganic-rich peat (Ti ~0.2 to 0.4 wt. %) are lowest (0.7074-0.7080) for older samples (>2,750 cal yrs BP), and highest (0.7085-0.7091) for youngest samples (last ~150 yrs). This is consistent with BRI being more saline than FW or BACHI during the past several thousand years, assuming minimal post-depositional exchange of Sr. The assumption that peat organic fraction incorporates Sr dissolved in ambient

  19. Isotope engineering of carbon nanotube systems.

    PubMed

    Simon, F; Kramberger, Ch; Pfeiffer, R; Kuzmany, H; Zólyomi, V; Kürti, J; Singer, P M; Alloul, H

    2005-07-01

    The synthesis of a unique isotope engineered system, double-wall carbon nanotubes with natural carbon outer and highly 13C enriched inner walls, is reported from isotope enriched fullerenes encapsulated in single-wall carbon nanotubes (SWCNTs). The material allows the observation of the D line of the highly defect-free inner tubes that can be related to a curvature induced enhancement of the electron-phonon coupling. Ab initio calculations explain the inhomogeneous broadening of inner tube Raman modes due to the distribution of different isotopes. Nuclear magnetic resonance shows a significant contrast of the isotope enriched inner SWCNTs compared to other carbon phases and provides a macroscopic measure of the inner tube mass content. The high curvature of the small diameter inner tubes manifests in an increased distribution of the chemical shift tensor components.

  20. Isotope Engineering of Carbon Nanotube Systems

    NASA Astrophysics Data System (ADS)

    Simon, F.; Kramberger, Ch.; Pfeiffer, R.; Kuzmany, H.; Zólyomi, V.; Kürti, J.; Singer, P. M.; Alloul, H.

    2005-06-01

    The synthesis of a unique isotope engineered system, double-wall carbon nanotubes with natural carbon outer and highly 13C enriched inner walls, is reported from isotope enriched fullerenes encapsulated in single-wall carbon nanotubes (SWCNTs). The material allows the observation of the D line of the highly defect-free inner tubes that can be related to a curvature induced enhancement of the electron-phonon coupling. Ab initio calculations explain the inhomogeneous broadening of inner tube Raman modes due to the distribution of different isotopes. Nuclear magnetic resonance shows a significant contrast of the isotope enriched inner SWCNTs compared to other carbon phases and provides a macroscopic measure of the inner tube mass content. The high curvature of the small diameter inner tubes manifests in an increased distribution of the chemical shift tensor components.

  1. Bacterially induced calcium carbonate precipitation and strontium coprecipitation in a porous media flow system.

    PubMed

    Lauchnor, Ellen G; Schultz, Logan N; Bugni, Steven; Mitchell, Andrew C; Cunningham, Alfred B; Gerlach, Robin

    2013-02-05

    Strontium-90 is a principal radionuclide contaminant in the subsurface at several Department of Energy sites in the Western U.S., causing a threat to groundwater quality in areas such as Hanford, WA. In this work, we used laboratory-scale porous media flow cells to examine a potential remediation strategy employing coprecipitation of strontium in carbonate minerals. CaCO(3) precipitation and strontium coprecipitation were induced via ureolysis by Sporosarcina pasteurii in two-dimensional porous media reactors. An injection strategy using pulsed injection of calcium mineralization medium was tested against a continuous injection strategy. The pulsed injection strategy involved periods of lowered calcite saturation index combined with short high fluid velocity flow periods of calcium mineralization medium followed by stagnation (no-flow) periods to promote homogeneous CaCO(3) precipitation. By alternating the addition of mineralization and growth media the pulsed strategy promoted CaCO(3) precipitation while sustaining the ureolytic culture over time. Both injection strategies achieved ureolysis with subsequent CaCO(3) precipitation and strontium coprecipitation. The pulsed injection strategy precipitated 71-85% of calcium and 59% of strontium, while the continuous injection was less efficient and precipitated 61% of calcium and 56% of strontium. Over the 60 day operation of the pulsed reactors, ureolysis was continually observed, suggesting that the balance between growth and precipitation phases allowed for continued cell viability. Our results support the pulsed injection strategy as a viable option for ureolysis-induced strontium coprecipitation because it may reduce the likelihood of injection well accumulation caused by localized mineral plugging while Sr coprecipitation efficiency is maintained in field-scale applications.

  2. Sulfur and strontium isotope geochemistry of tributary rivers of Lake Biwa: implications for human impact on the decadal change of lake water quality.

    PubMed

    Nakano, Takanori; Tayasu, Ichiro; Wada, Eitaro; Igeta, Akitake; Hyodo, Fujio; Miura, Yuuta

    2005-06-01

    To study the deterioration of the water quality in Lake Biwa, Japan, over the last 40 years, we measured the concentrations and isotopic ratios of sulfur and strontium of water in 41 inflowing rivers and one discharging river. The concentrations of SO4 and Sr of inflowing rivers at downstream sites were generally high in the southern urban area and in the eastern area, where a large agricultural plain is situated, but low in the northern and western areas, whose watersheds are mountainous and with low population density. SO4 and Sr concentrations are also lower at upstream sites, which are closer to mountainous areas. Thus, the inflowing river receives large amounts of SO4 and Sr as it flows across the plain, where human activity levels are high. The delta34S or 87Sr/86Sr values of most eastern rivers at downstream sites are lower than those of water in Lake Biwa, and values become more uniform as the proportion of the plain area in the watershed increases. River water in other areas has higher values of delta34S or 87Sr/86Sr than the lake water. This result indicates that the decadal decrease of delta34S and 87Sr/86Sr in the lake water has been caused mainly by the increased flux of SO4 and Sr from rivers in the eastern plain. We assume that in the plain, sulfur, nitrogen, and organic compounds induced by human activities generate sulfuric, nitric, and organic acids in the water, which accelerate the extraction of Sr from bedrocks, leading to the generation of Sr in the river water in the area.

  3. Fit for purpose validated method for the determination of the strontium isotopic signature in mineral water samples by multi-collector inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Brach-Papa, Christophe; Van Bocxstaele, Marleen; Ponzevera, Emmanuel; Quétel, Christophe R.

    2009-03-01

    A robust method allowing the routine determination of n( 87Sr)/ n( 86Sr) with at least five significant decimal digits for large sets of mineral water samples is described. It is based on 2 consecutive chromatographic separations of Sr associated to multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) measurements. Separations are performed using commercial pre-packed columns filled with "Sr resin" to overcome isobaric interferences affecting the determination of strontium isotope ratios. The careful method validation scheme applied is described. It included investigations on all parameters influencing both chromatographic separations and MC-ICPMS measurements, and also the test on a synthetic sample made of an aliquot of the NIST SRM 987 certified reference material dispersed in a saline matrix to mimic complex samples. Correction for mass discrimination was done internally using the n( 88Sr)/ n( 86Sr) ratio. For comparing mineral waters originating from different geological backgrounds or identifying counterfeits, calculations involved the well known consensus value (1/0.1194) ± 0 as reference. The typical uncertainty budget estimated for these results was 40 'ppm' relative ( k = 2). It increased to 150 'ppm' ( k = 2) for the establishment of stand alone results, taking into account a relative difference of about 126 'ppm' systematically observed between measured and certified values of the NIST SRM 987. In case there was suspicion of a deviation of the n( 88Sr)/ n( 86Sr) ratio (worst case scenario) our proposal was to use the NIST SRM 987 value 8.37861 ± 0.00325 ( k = 2) as reference, and assign a typical relative uncertainty budget of 300 'ppm' ( k = 2). This method is thus fit for purpose and was applied to eleven French samples.

  4. Lead and strontium isotopic evidence for crustal interaction and compositional zonation in the source regions of Pleistocene basaltic and rhyolitic magmas of the Coso volcanic field, California

    USGS Publications Warehouse

    Bacon, C.R.; Kurasawa, H.; Delevaux, M.H.; Kistler, R.W.; Doe, B.R.

    1984-01-01

    The isotopic compositions of Pb and Sr in Pleistocene basalt, high-silica rhyolite, and andesitic inclusions in rhyolite of the Coso volcanic field indicate that these rocks were derived from different levels of compositionally zoned magmatic systems. The 2 earliest rhyolites probably were tapped from short-lived silicic reservoirs, in contrast to the other 36 rhyolite domes and lava flows which the isotopic data suggest may have been leaked from the top of a single, long-lived magmatic system. Most Coso basalts show isotopic, geochemical, and mineralogic evidence of interaction with crustal rocks, but one analyzed flow has isotopic ratios that may represent mantle values (87Sr/86Sr=0.7036,206Pb/204Pb=19.05,207Pb/204Pb=15.62,208Pb/204Pb= 38.63). The (initial) isotopic composition of typical rhyolite (87Sr/86Sr=0.7053,206Pb/204Pb=19.29,207Pb/204Pb= 15.68,208Pb/204Pb=39.00) is representative of the middle or upper crust. Andesitic inclusions in the rhyolites are evidently samples of hybrid magmas from the silicic/mafic interface in vertically zoned magma reservoirs. Silicic end-member compositions inferred for these mixed magmas, however, are not those of erupted rhyolite but reflect the zonation within the silicic part of the magma reservoir. The compositional contrast at the interface between mafic and silicic parts of these systems apparently was greater for the earlier, smaller reservoirs. ?? 1984 Springer-Verlag.

  5. Strontium concentrations in corrosion products from residential drinking water distribution systems.

    PubMed

    Gerke, Tammie L; Little, Brenda J; Luxton, Todd P; Scheckel, Kirk G; Maynard, J Barry

    2013-05-21

    The United States Environmental Protection Agency (US EPA) will require some U.S. drinking water distribution systems (DWDS) to monitor nonradioactive strontium (Sr(2+)) in drinking water in 2013. Iron corrosion products from four DWDS were examined to assess the potential for Sr(2+) binding and release. Average Sr(2+) concentrations in the outermost layer of the corrosion products ranged from 3 to 54 mg kg(-1) and the Sr(2+) drinking water concentrations were all ≤0.3 mg L(-1). Micro-X-ray adsorption near edge structure spectroscopy and linear combination fitting determined that Sr(2+) was principally associated with CaCO3. Sr(2+) was also detected as a surface complex associated with α-FeOOH. Iron particulates deposited on a filter inside a home had an average Sr(2+) concentration of 40.3 mg kg(-1) and the associated drinking water at a tap was 210 μg L(-1). The data suggest that elevated Sr(2+) concentrations may be associated with iron corrosion products that, if disturbed, could increase Sr(2+) concentrations above the 0.3 μg L(-1) US EPA reporting threshold. Disassociation of very small particulates could result in drinking water Sr(2+) concentrations that exceed the US EPA health reference limit (4.20 mg kg(-1) body weight).

  6. The enigmatic Messinian-Pliocene section of Cuevas del Almanzora (Vera Basin, SE Spain) revisited—erosional features and strontium isotope ages

    NASA Astrophysics Data System (ADS)

    Fortuin, A. R.; Kelling, J. M. D.; Roep, Th. B.

    1995-07-01

    The Cuevas del Almanzora section was, in the late seventies, the focus of a discussion because of alleged continuous marine Messinian to Pliocene sedimentation. However, a discontinuity has been shown to exist in the shape of laminated strata including the late Messinian brackish/ lacustrine "Lago Mare" biofacies. More recently, Benson and Rakic-El Bied (1991) concluded that the section is still one of the best biostratigraphic successions for the western Mediterranean in which to document terminal Miocene events, but that it entirely has an early Messinian age (i.e. it antedates deposition of the main evaporites). This paper presents strontium isotope ages indicating that the "classic" threefold division in an earlier marine Messinian, a "Lago Mare", and a Pliocene interval (sensu Geerlings et al., 1980; Cita et al., 1980) should be maintained. Moreover, the Sr isotopic composition of the euryhaline Cyprideis ostracodes from the "Lago Mare" laminites is similar to those from central Mediterranean basins. This stresses the importance of late Messinian water exchange between the Vera Basin and the then enclosed Mediterranean. It thus refutes the opinion of Benson and Rakic-El Bied (1991) that this interval is a local facies, of no particular stratigraphic importance. A time gap of up to ˜0.8 Ma between the youngest marine strata of the Messinian and the overlying Pliocene provides a maximum timing for the duration of the Messinian salinity crisis during which very little net sedimentation occurred, compared to coeval deposits in, for example, the nearby Nijar and Sorbas basins. In the Cuevas section an inconspicuous, and hitherto overlooked, erosional gap has been observed. This separates the "Lago Mare" marls from the Pliocene marls. More field observations have been made and are discussed in the light of existing interpretations, in order to demonstrate the importance of more widespread erosion in the Vera Basin. Gypsum-containing mass-flow deposits, filling up a

  7. New Perspectives on the Marine Strontium Isotope Record of the last 27 Ma from delta 88/86Sr and 87Sr/86Sr Systematics Using the TIMS Sr-Double-Spike Technique

    NASA Astrophysics Data System (ADS)

    Liebetrau, V.; Eisenhauer, A.; Krabbenhoeft, A.; Fietzke, J.; Rueggeberg, A.; Guers, K.

    2008-12-01

    Applying a recently developed Sr-double spike the Sr-isotope fractionation for both 88Sr/86Sr and 87Sr/86Sr ratios in water and carbonates can now precisely be determined with the TIMS- technique. Repeated measurements of standard materials (NIST SRM 987, IAPSO seawater standard, JCp-1 carbonate standard) showed that δ 88Sr/86Sr (reported as δ 88/86Sr=((88Sr/86Sr)sample/(88Sr/86Sr)NBS987)-1)*1000) and 87Sr/86Sr ratios can be determined with an external reproducibility in the order of better than 20 ppm and about 6 ppm, respectively, for NIST SRM 987, IAPSO and JCp-1, respectively. Using the double spike TIMS technique the statistical error for determination of δ 88/86Sr is reaching a whole procedure reproducibility of about 15 ppm. All standard measurements are in general accord with previous observations (1,2) indicating that δ 88/86Srseawater and 87Sr/86Srseawater is about 0.39±0.02 ‰ and 0.709285(6) , (n=12), respectively, and that the marine carbonates being isotopically lighter than seawater (JCp-1, δ 88Sr/86Sr: 0.20±0.02; 87Sr/86Sr : 0.709219(6); n=3). Note, that also 87Sr/86Sr carbonate ratios is isotopically about 70 ppm lighter than seawater as expected from isotope fractionation during the precipitation of calcium carbonates (1). For a first application of our double spike on 13 bulk carbonate samples of aragonitic composition, representing marine shallow water mollusks (0 to 100m water depth), it has been shown that their bio- stratigraphic ages are in accordance with the classical Strontium isotope stratigraphy (SIS) after McArthur and Howarth (2004). The samples span an age range from the the Late Oligocene to Pleistocene (about 27 Ma). The δ 88Sr/86Sr-record shows variations in the order of about 0.2 ‰. The 87Sr/86Srseawater record tends to show higher values compared to the classical normalized 87Sr/86Sr record. The offset is not constant rather correlated to the 88Sr/86Sr ratios. Preliminary interpretation take seawater temperature

  8. Laser sources for precision spectroscopy on atomic strontium.

    PubMed

    Poli, N; Ferrari, G; Prevedelli, M; Sorrentino, F; Drullinger, R E; Tino, G M

    2006-04-01

    We present a new laser setup designed for high-precision spectroscopy on laser cooled atomic strontium. The system, which is entirely based on semiconductor laser sources, delivers 200 mW at 461 nm for cooling and trapping atomic strontium from a thermal source, 4 mW at 497 nm for optical pumping from the metastable P23 state, 12 mW at 689 nm on linewidth less than 1 kHz for second-stage cooling of the atomic sample down to the recoil limit, 1.2 W at 922 nm for optical trapping close to the "magic wavelength" for the 0-1 intercombination line at 689 nm. The 689 nm laser was already employed to perform a frequency measurement of the 0-1 intercombination line with a relative accuracy of 2.3 x 10(-11), and the ensemble of laser sources allowed the loading in a conservative dipole trap of multi-isotopes strontium mixtures. The simple and compact setup developed represents one of the first steps towards the realization of a transportable optical standards referenced to atomic strontium.

  9. Strontium isotopic constraints on the origin of ore-forming fluids of the Viburnum Trend, southeast Missouri

    USGS Publications Warehouse

    Brannon, J.C.; Podosek, F.A.; Viets, J.G.; Leach, D.L.; Goldhabe, M.; Rowan, E.L.

    1991-01-01

    We have measured 87Sr 86Sr and Rb and Sr concentrations in several minerals, primarily sulfides, spanning the paragenesis of hydrothermal mineralization in the Viburnum Trend in southeast Missouri. Separate measurements were made for fluid inclusions opened by crushing or thermal decrepitation and for the solids. For comparison, measurements were also made on samples of probable local aquifers, the Bonneterre Formation and the Lamotte Sandstone. For some of the samples, concentrations of K, Ca, Cl, Na, and Mg are also reported. In several cases 87Sr 86Sr ratios are different (higher) in the solids than in the fluid inclusions. We have investigated the possibility that either type of sample gives spurious results, e.g., that the fluid inclusions are secondary or contaminated by host dolomite, or that Sr in the solids reflects a detrital rather than an authigenic source. Consideration of mass balance, overall solute chemistry, and examination of non-sulfide dissolution residue, however, suggests that both types of sample reflect primary fluid Sr composition. We thus adopt the working hypothesis that Sr isotopic composition in fluids at the time of hydrothermal mineralization was highly variable. The observed results for the Viburnum Trend do not conform well to expected trends for Mississippi Valley-type (MVT) mineralization based primarily on analyses of gangue carbonates, barite, and fluorite. Fluid inclusion Sr in some of the Viburnum Trend samples is more radiogenic than in the host dolomite but only moderately so; in other samples, notably main-stage octahedral galena, fluid inclusion Sr composition is within the range observed for the host dolomite. In contrast, Sr in some of the sulfides is very radiogenic, much more so than previously reported for MVT minerals, and is very radiogenic early in the paragenesis (pyrite, chalcopyrite, sphalerite), less radiogenic during main-stage ore deposition, and again more radiogenic in later paragenetic stages. ?? 1991.

  10. Determination of the strontium isotope ratio by ICP-MS ginseng as a tracer of regional origin.

    PubMed

    Choi, Sung-Min; Lee, Hae-Suk; Lee, Gae-Ho; Han, Jae-Kil

    2008-06-01

    This study presents the inductively coupled plasma mass spectrometry (ICP-MS) as a method for tracing the regional origin of ginseng. The results of the analysis of 15 Korean ginsengs from three different regions and of 15 Chinese ginsengs from three different regions reveal that the Sr isotope ratios (87)Sr/(86)Sr of the ginsengs differed according to their origin. For pretreatment, the ginseng samples were dried, and were dissolved through microwave digestion, then were each made to amount to 6ml with 11.9M HCl. Rb was then separated from Sr to enable an interference-free measurement through cation exchange chromatography. Six millilitres of the ginseng sample were injected in the column, and 60ml of 11.9M HCl was passed through the column at a 1mlmin(-1) flow rate to separate Rb from Sr. After Rb was eluted completely, 60ml of 5.0M HCl was passed at a 1mlmin(-1) flow rate to collect Sr. In the Sr collection step, the first 10ml portion of 30ml eluate was discarded, and the next 10ml portion was taken and was diluted with de-ionized water at a ratio of 1:3, for analysis purposes. The results of the analysis of 30 ginseng samples revealed that the Chinese ginsengs have an (87)Sr/(86)Sr ratio range of 0.672-0.701, and the Korean ginsengs 0.705-0.714. The Korean ginsengs, therefore, have a higher (87)Sr/(86)Sr ratio range than the Chinese ginsengs. Of the Korean ginsengs, (87)Sr/(86)Sr ratio range of ginsengs from Punggi, Geumsan and Hongcheon are about 0.706-0.709, 0.705-0.706, and 0.710-0.714, respectively. Copyright © 2007 Elsevier Ltd. All rights reserved.

  11. Strontium and oxygen isotope study of M-1, M-3 and M-4 drill core samples from the Manson impact structure, Iowa: Comparison with Haitian K-T impact glasses

    NASA Technical Reports Server (NTRS)

    Blum, Joel D.; Chamberlain, C. Page; Hingston, Michael P.; Koeberl, Christian

    1993-01-01

    Strontium and oxygen isotope analyses were performed on 8 samples from the M-1, M-3, and M-4 cores recently drilled at the Manson impact structure. The samples were three elastic sedimentary rocks (of probable Cretaceous age) which occurred as clasts within the sedimentary clast breccia, two samples of crystalline rock breccia matrix, and three samples of dolomite and limestone. The Sr-87/Sr-86 (corrected to 65 Ma) ratios were much higher than those in impact glasses from the Haitian Cretaceous-Tertiary (K-T) boundary. Isotope mixing calculations demonstrate that neither the silicate or carbonate rocks analyzed from the Manson crater, or mixtures of these rocks are appropriate source materials for the Haitian impact glasses. However, the Sr-87/Sr-86 (65Ma) ratio and delta O-18 value of the Ca-rich Haitian glasses are well reproduced by mixtures of Si-rich Haitian glass with platform carbonate of K-T age.

  12. Strontium and oxygen isotope study of M-1, M-3 and M-4 drill core samples from the Manson impact structure, Iowa: Comparison with Haitian K-T impact glasses

    NASA Technical Reports Server (NTRS)

    Blum, Joel D.; Chamberlain, C. Page; Hingston, Michael P.; Koeberl, Christian

    1993-01-01

    Strontium and oxygen isotope analyses were performed on 8 samples from the M-1, M-3, and M-4 cores recently drilled at the Manson impact structure. The samples were three elastic sedimentary rocks (of probable Cretaceous age) which occurred as clasts within the sedimentary clast breccia, two samples of crystalline rock breccia matrix, and three samples of dolomite and limestone. The Sr-87/Sr-86 (corrected to 65 Ma) ratios were much higher than those in impact glasses from the Haitian Cretaceous-Tertiary (K-T) boundary. Isotope mixing calculations demonstrate that neither the silicate or carbonate rocks analyzed from the Manson crater, or mixtures of these rocks are appropriate source materials for the Haitian impact glasses. However, the Sr-87/Sr-86 (65Ma) ratio and delta O-18 value of the Ca-rich Haitian glasses are well reproduced by mixtures of Si-rich Haitian glass with platform carbonate of K-T age.

  13. Strontium isotopes and rare-earth element geochemistry of hydrothermal carbonate deposits from Lake Tanganyika, East Africa

    SciTech Connect

    Barrat, J.A.; Boulegue, J.; Tiercelin, J.J.; Lesourd, M.

    2000-01-01

    At Cape Banza (North Tanganyika Lake), fluids and aragonite chimneys have been collected many times since the discovery of this sublacustrine field in 1987. This sampling has been investigated here for the Sr isotopic compositions and the rare-earth element features of the carbonates and a few fluid samples. The {sup 87}Sr/{sup 86}Sr ratios of the chimneys indicate that they have precipitated from a mixture of lake water (more than 95%) and hydrothermal fluids. No zoning in the chimneys was detected with the Sr data. For the rare-earth elements, the situation is more complex. The external walls of the chimneys are rare-earth-element-poor (La {approx} 500 ppb, Yb {approx} 200 ppb, La/Yb = 2 to 3.4). Their shale normalized rare-earth element patterns suggest that they are in equilibrium with the inferred carbonate-depositing fluids. The rare-earth element concentrations of the internal walls of the chimneys are significantly light rare earth elements (LREE)-enriched with La contents sometimes up to 5 ppm. The authors suggest that they contain more vent-fluid rare-earth elements than the external wall samples, possibly adsorbed on the surface of growing crystals or simply hosted by impurities. It was not possible to constrain the nature of these phases, but the variations of the compositions of the internal wall materials of the active chimneys with time, as well as data obtained on an inactive chimney indicate that this rare-earth element excess is mobile. Partition coefficients were calculated between the external wall aragonite and carbonate-depositing fluid. The results are strikingly similar to the values obtained by Sholkovitz and Shen (1995) on coral aragonite, and suggest that there is no significant biologic effect on the incorporation of rare-earth elements into coral aragonite and that the various carbonate complexes involved Me(CO{sub 3}{sup +}) complexes are the main LREE carriers in seawater instead of Me(CO{sub 3}){sub 2}{sup {minus}} in Banza fluids

  14. Pure hydroxyapatite phantoms for the calibration of in vivo X-ray fluorescence systems of bone lead and strontium quantification.

    PubMed

    Da Silva, Eric; Kirkham, Brian; Heyd, Darrick V; Pejović-Milić, Ana

    2013-10-01

    Plaster of Paris [poP, CaSO4·(1)/(2) H2O] is the standard phantom material used for the calibration of in vivo X-ray fluorescence (IVXRF)-based systems of bone metal quantification (i.e bone strontium and lead). Calibration of IVXRF systems of bone metal quantification employs the use of a coherent normalization procedure which requires the application of a coherent correction factor (CCF) to the data, calculated as the ratio of the relativistic form factors of the phantom material and bone mineral. Various issues have been raised as to the suitability of poP for the calibration of IVXRF systems of bone metal quantification which include its chemical purity and its chemical difference from bone mineral (a calcium phosphate). This work describes the preparation of a chemically pure hydroxyapatite phantom material, of known composition and stoichiometry, proposed for the purpose of calibrating IVXRF systems of bone strontium and lead quantification as a replacement for poP. The issue with contamination by the analyte was resolved by preparing pure Ca(OH)2 by hydroxide precipitation, which was found to bring strontium and lead levels to <0.7 and <0.3 μg/g Ca, respectively. HAp phantoms were prepared from known quantities of chemically pure Ca(OH)2, CaHPO4·2H2O prepared from pure Ca(OH)2, the analyte, and a HPO4(2-) containing setting solution. The final crystal structure of the material was found to be similar to that of the bone mineral component of NIST SRM 1486 (bone meal), as determined by powder X-ray diffraction spectrometry.

  15. Robust Medical Isotope Production System

    SciTech Connect

    Klein, Steven Karl; Kimpland, Robert Herbert

    2015-06-15

    The success of this theoretical undertaking provided confidence that the behavior of new and evolving designs of fissile solution systems may be accurately estimated. Scaled up versions of SUPO, subcritical acceleratordriven systems, and other evolutionary designs have been examined.

  16. Impacts of Dust on Tropical Volcanic Soil Formation: Insights from Strontium and Uranium-Series Isotopes in Soils from Basse-Terre Island, French Guadeloupe

    NASA Astrophysics Data System (ADS)

    Pereyra, Y.; Ma, L.; Sak, P. B.; Gaillardet, J.; Buss, H. L.; Brantley, S. L.

    2015-12-01

    Dust inputs play an important role in soil formation, especially for thick soils developed on tropical volcanic islands. In these regions, soils are highly depleted due to intensive chemical weathering, and mineral nutrients from dusts have been known to be important in sustaining soil fertility and productivity. Tropical volcanic soils are an ideal system to study the impacts of dust inputs on the ecosystem. Sr and U-series isotopes are excellent tracers to identify sources of materials in an open system if the end-members have distinctive isotope signatures. These two isotope systems are particularly useful to trace the origin of atmospheric inputs into soils and to determine rates and timescales of soil formation. This study analyzes major elemental concentrations, Sr and U-series isotope ratios in highly depleted soils in the tropical volcanic island of Basse-Terre in French Guadeloupe to determine atmospheric input sources and identify key soil formation processes. We focus on three soil profiles (8 to 12 m thick) from the Bras-David, Moustique Petit-Bourg, and Deshaies watersheds; and on the adjacent rivers to these sites. Results have shown a significant depletion of U, Sr, and major elements in the deep profile (12 to 4 m) attributed to rapid chemical weathering. The top soil profiles (4 m to the surface) all show addition of elements such as Ca, Mg, U, and Sr due to atmospheric dust. More importantly, the topsoil profiles have distinct Sr and U-series isotope compositions from the deep soils. Sr and U-series isotope ratios of the top soils and sequential extraction fractions confirm that the sources of the dust are from the Saharan dessert, through long distance transport from Africa to the Caribbean region across the Atlantic Ocean. During the transport, some dust isotope signatures may also have been modified by local volcanic ashes and marine aerosols. Our study highlights that dusts and marine aerosols play important roles in element cycles and

  17. Strontium Isotopic Composition of Paleozoic Carbonate Rocks in the Nevada Test Site Vicinity, Clark, Lincoln, and Nye Counties, Nevada and Inyo County, California.

    SciTech Connect

    James B. Paces; Zell E. Peterman; Kiyoto Futa; Thomas A. Oliver; and Brian D. Marshall.

    2007-08-07

    Ground water moving through permeable Paleozoic carbonate rocks represents the most likely pathway for migration of radioactive contaminants from nuclear weapons testing at the Nevada Test Site, Nye County, Nevada. The strontium isotopic composition (87Sr/86Sr) of ground water offers a useful means of testing hydrochemical models of regional flow involving advection and reaction. However, reaction models require knowledge of 87Sr/86Sr data for carbonate rock in the Nevada Test Site vicinity, which is scarce. To fill this data gap, samples of core or cuttings were selected from 22 boreholes at depth intervals from which water samples had been obtained previously around the Nevada Test Site at Yucca Flat, Frenchman Flat, Rainier Mesa, and Mercury Valley. Dilute acid leachates of these samples were analyzed for a suite of major- and trace-element concentrations (MgO, CaO, SiO2, Al2O3, MnO, Rb, Sr, Th, and U) as well as for 87Sr/86Sr. Also presented are unpublished analyses of 114 Paleozoic carbonate samples from outcrops, road cuts, or underground sites in the Funeral Mountains, Bare Mountain, Striped Hills, Specter Range, Spring Mountains, and ranges east of the Nevada Test Site measured in the early 1990's. These data originally were collected to evaluate the potential for economic mineral deposition at the potential high-level radioactive waste repository site at Yucca Mountain and adjacent areas (Peterman and others, 1994). Samples were analyzed for a suite of trace elements (Rb, Sr, Zr, Ba, La, and Ce) in bulk-rock powders, and 87Sr/86Sr in partial digestions of carbonate rock using dilute acid or total digestions of silicate-rich rocks. Pre-Tertiary core samples from two boreholes in the central or western part of the Nevada Test Site also were analyzed. Data are presented in tables and summarized in graphs; however, no attempt is made to interpret results with respect to ground-water flow paths in this report. Present-day 87Sr/86Sr values are compared to values

  18. Identifying calcium sources at an acid deposition-impacted spruce forest: A strontium isotope, alkaline earth element multi-tracer approach

    USGS Publications Warehouse

    Bullen, T.D.; Bailey, S.W.

    2005-01-01

    Depletion of calcium from forest soils has important implications for forest productivity and health. Ca is available to fine feeder roots from a number of soil organic and mineral sources, but identifying the primary source or changes of sources in response to environmental change is problematic. We used strontium isotope and alkaline earth element concentration ratios of trees and soils to discern the record of Ca sources for red spruce at a base-poor, acid deposition-impacted watershed. We measured 87Sr/86Sr and chemical compositions of cross-sectional stemwood cores of red spruce, other spruce tissues and sequential extracts of co-located soil samples. 87Sr/86Sr and Sr/Ba ratios together provide a tracer of alkaline earth element sources that distinguishes the plant-available fraction of the shallow organic soils from those of deeper organic and mineral soils. Ca/Sr ratios proved less diagnostic, due to within-tree processes that fractionate these elements from each other. Over the growth period from 1870 to 1960, 87Sr/86Sr and Sr/Ba ratios of stemwood samples became progressively more variable and on average trended toward values that considered together are characteristic of the uppermost forest floor. In detail the stemwood chemistry revealed an episode of simultaneous enhanced uptake of all alkaline earth elements during the growth period from 1930 to 1960, coincident with reported local and regional increases in atmospheric inputs of inorganic acidity. We attribute the temporal trends in stemwood chemistry to progressive shallowing of the effective depth of alkaline earth element uptake by fine roots over this growth period, due to preferential concentration of fine roots in the upper forest floor coupled with reduced nutrient uptake by roots in the lower organic and upper mineral soils in response to acid-induced aluminum toxicity. Although both increased atmospheric deposition and selective weathering of Ca-rich minerals such as apatite provide possible

  19. Strontium Isotopic Composition of Paleozoic Carbonate Rocks in the Nevada Test Site Vicinity, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California

    USGS Publications Warehouse

    Paces, James B.; Peterman, Zell E.; Futo, Kiyoto; Oliver, Thomas A.; Marshall, Brian D.

    2007-01-01

    Ground water moving through permeable Paleozoic carbonate rocks represents the most likely pathway for migration of radioactive contaminants from nuclear weapons testing at the Nevada Test Site, Nye County, Nevada. The strontium isotopic composition (87Sr/86Sr) of ground water offers a useful means of testing hydrochemical models of regional flow involving advection and reaction. However, reaction models require knowledge of 87Sr/86Sr data for carbonate rock in the Nevada Test Site vicinity, which is scarce. To fill this data gap, samples of core or cuttings were selected from 22 boreholes at depth intervals from which water samples had been obtained previously around the Nevada Test Site at Yucca Flat, Frenchman Flat, Rainier Mesa, and Mercury Valley. Dilute acid leachates of these samples were analyzed for a suite of major- and trace-element concentrations (MgO, CaO, SiO2, Al2O3, MnO, Rb, Sr, Th, and U) as well as for 87Sr/86Sr. Also presented are unpublished analyses of 114 Paleozoic carbonate samples from outcrops, road cuts, or underground sites in the Funeral Mountains, Bare Mountain, Striped Hills, Specter Range, Spring Mountains, and ranges east of the Nevada Test Site measured in the early 1990's. These data originally were collected to evaluate the potential for economic mineral deposition at the potential high-level radioactive waste repository site at Yucca Mountain and adjacent areas (Peterman and others, 1994). Samples were analyzed for a suite of trace elements (Rb, Sr, Zr, Ba, La, and Ce) in bulk-rock powders, and 87Sr/86Sr in partial digestions of carbonate rock using dilute acid or total digestions of silicate-rich rocks. Pre-Tertiary core samples from two boreholes in the central or western part of the Nevada Test Site also were analyzed. Data are presented in tables and summarized in graphs; however, no attempt is made to interpret results with respect to ground-water flow paths in this report. Present-day 87Sr/86Sr values are compared to values

  20. Cosmic ray produced isotopes in terrestrial systems.

    NASA Astrophysics Data System (ADS)

    Lal, D.

    1998-12-01

    Continuing improvements in the sensitivity of measurement of cosmic ray produced isotopes in environmental samples have progressively broadened the scope of their applications to characterise and quantify a wide variety of processes in Earth and planetary sciences. In this article, the author concentrates on the new developments in the field of nuclear geophysics, based on isotopic changes produced by cosmic rays in the terrestrial systems. This field, which is best described as cosmic ray geophysics, has roots with the discovery of cosmogenic 14C on the Earth by Willard Libby in 1948, and grew rapidly at first, but slowed down during the '60s and '70s. In the '80s, there was a renaissance in cosmic ray produced isotope studies, thanks mainly to the developments of the accelerator mass spectrometry technique capable of measuring minute amounts of radioactivity in terrestrial samples. This technological advance has considerably enhanced the applications of cosmic ray produced isotopes and today one finds them being used to address diverse problems in Earth and planetary sciences. The author discusses the present scope of the field of cosmic ray geophysics with an emphasis on geomorphology. It is stressed that this is the decade in which this field, which has been studied passionately by geographers, geomorphologists and geochemists for more than five decades, has at its service nuclear methods to introduce numeric time controls in the range of centuries to millions of years.

  1. Quantum Degenerate Gases of Strontium

    NASA Astrophysics Data System (ADS)

    Desalvo, Brian; Martinez de Escobar, Natali; Mickelson, Pacal; Yan, Mi; Killian, Thomas

    2010-03-01

    We have produced quantum degenerate gases of three of the four stable isotopes of strontium. Using two-stage laser trapping and cooling followed by direct evaporative cooling in a far-off- resonance optical dipole trap (ODT), a stable Bose-Einstein Condensate (BEC) of ^84Sr is formed. Via dual species trapping and sympathetic cooling in an ODT, an attractive BEC of ^88Sr is created, as well as a degenerate Fermi gas of ^87Sr. Differences in the evaporation scheme used to reach degeneracy for each isotope will be presented as well as the varied dynamics of the gases.

  2. Reconstruction of crustal blocks of California on the basis of initial strontium isotopic compositions of Mesozoic granitic rocks

    USGS Publications Warehouse

    Kistler, Ronald Wayne; Peterman, Zell E.

    1978-01-01

    Initial 87Sr/ 86 Sr was determined for samples of Mesozoic granitic rocks in the vicinity of the Garlock fault zone in California. These data along with similar data from the Sierra Nevada and along the San Andreas fault system permit a reconstruction of basement rocks offset by the Cenozoic lateral faulting along both the San Andreas and Garlock fault systems. The location of the line of initial 87Sr/ 86 Sr = 0.7060 can be related to the edge of the Precambrian continental crust in the western United States. Our model explains the present configuration of the edge of Precambrian continental crust as the result of two stages of rifting that occurred about 1,250 to 800 m.y. ago, during Belt sedimentation, and about 600 to 350 m.y. ago, prior to and during the development of the Cordilleran geosyncline and to left-lateral translation along a locus of disturbance identified in the central Mojave Desert. The variations in Rb, Sr, and initial 87Sr/ 86 Sr of the Mesozoic granitic rocks are interpreted as due to variations in composition and age of the source materials of the granitic rocks. The variations of Rb, Sr, and initial 87Sr/ 86 Sr in Mesozoic granitic rocks, the sedimentation history during the late Precambrian and Paleozoic, and the geographic position of loci of Mesozoic magmatism in the western United States are related to the development of the continental margin and different types of lithosphere during rifting.

  3. Optically pumped isotopic ammonia laser system

    DOEpatents

    Buchwald, Melvin I.; Jones, Claude R.; Nelson, Leonard Y.

    1982-01-01

    An optically pumped isotopic ammonia laser system which is capable of producing a plurality of frequencies in the middle infrared spectral region. Two optical pumping mechanisms are disclosed, i.e., pumping on R(J) and lasing on P(J) in response to enhancement of rotational cascade lasing including stimulated Raman effects, and, pumping on R(J) and lasing on P(J+2). The disclosed apparatus for optical pumping include a hole coupled cavity and a grating coupled cavity.

  4. Strontium isotope systematics of scheelite and apatite from the Felbertal tungsten deposit, Austria - results of in-situ LA-MC-ICP-MS analysis

    NASA Astrophysics Data System (ADS)

    Kozlik, Michael; Gerdes, Axel; Raith, Johann G.

    2016-02-01

    The in-situ Sr isotopic systematics of scheelite and apatite from the Felbertal W deposit and a few regional Variscan orthogneisses ("Zentralgneise") have been determined by LA-MC-ICP-MS. The 87Sr/86Sr ratios of scheelite and apatite from the deposit are highly radiogenic and remarkably scattering. In the early magmatic-hydrothermal scheelite generations (Scheelite 1 and 2) the 87Sr/86Sr ratios range from 0.72078 to 0.76417 and from 0.70724 to 0.76832, respectively. Metamorphic Scheelite 3, formed by recrystallisation and local mobilisation of older scheelite, is characterised by even higher 87Sr/86Sr values between 0.74331 and 0.80689. Statistics allows discriminating the three scheelite generations although there is considerable overlap between Scheelite 1 and 2; they could be mixtures of the same isotopic reservoirs. The heterogeneous and scattering 87Sr/86Sr ratios of the two primary scheelite generations suggest modification of the Sr isotope system due to fluid-rock interaction and isotopic disequilibrium. Incongruent release of 87Sr from micas in the Early Palaeozoic host rocks of the Habach Complex contributed to the solute budget of the hydrothermal fluids and may explain the radiogenic Sr isotope signature of scheelite. Spatially resolved analyses revealed isotopic disequilibrium even on a sub-mm scale within zoned Scheelite 2 crystals indicating scheelite growth in an isotopic dynamical hydrothermal system. Zoned apatite from the W mineralised Early Carboniferous K1-K3 orthogneiss in the western ore field yielded 87Sr/86Sr of 0.72044-0.74514 for the cores and 0.74535-0.77937 for the rims. Values of magmatic apatite cores from the K1-K3 orthogneiss are comparable to those of primary Scheelite 1; they are too radiogenic to be magmatic. The Sr isotopic composition of apatite cores was therefore equally modified during the hydrothermal mineralisation processes, therefore supporting the single-stage genetic model in which W mineralisation is associated with

  5. Trace element and strontium isotope characteristics of volcanic rocks from Isla Tortuga: a young seamount in the Gulf of California

    USGS Publications Warehouse

    Batiza, Rodey; Futa, K.; Hedge, C.E.

    1979-01-01

    Isla Tortuga is a small isolated central volcano which is located near an actively spreading trough in the Gulf of California. The basalt lavas from Tortuga which have the highest Mg/Fe and Ni contents have trace element abundances and ratios and 87Sr/86Sr which are similar to those of mid-ocean ridge tholeiite. The major element, rare earth element and Sr abundances of fractionated tholeiite (low Mg/Fe) and tholeiitic andesite of Tortuga are consistent with an origin by closed-system fractional crystallization. This hypothesis is not supported by K, Na, Rb and Ba abundances in the lavas nor by their variable 87Sr/86Sr (0.7024-0.7035). It is proposed that the apparent decoupling of light rare earth elements, other incompatible trace elements and 87Sr/86Sr is due to contamination of some Tortuga magmas while they are fractionated in a high-level crustal magma chamber. The mantle source of least-contaminated, high Mg/Fe basalt lavas of Tortuga is similar, although not identical to the source of normal mid-ocean ridge tholeiite; significant differences exist. The reasons for these differences are not yet known. ?? 1979.

  6. Halite dissolution derived brines in the vicinity of a Permian salt dome (N German Basin). Evidence from boron, strontium, oxygen, and hydrogen isotopes

    NASA Astrophysics Data System (ADS)

    Kloppmann, W.; Négrel, Ph.; Casanova, J.; Klinge, H.; Schelkes, K.; Guerrot, C.

    2001-11-01

    The paper presents the isotopic (B, Sr, O, H) and chemical composition of solid salts, brines, groundwater, and surface water in the vicinity of a Permian salt dome in Northern Germany (diapir of Gorleben-Rambow) being considered for disposal of high level radioactive waste. The site is situated in the NW European Basin that is dominated by intensive diapirism of Permian salt and overprinted by glacial erosion/sedimentation. The local hydrogeology comprises an upper aquifer system of heterogeneous Pleistocene sediments and a lower aquifer system of Tertiary clastics tectonically disturbed by diapirism. There is a clear chemical and isotopic evolution with TDS, that generally increases with depth up to 328 g · l -1. The chemistry and isotope ratios of the saline groundwater can be explained by a two end-member mixing system. The Na-Cl brine end-member is derived from evaporite dissolution as indicated by major ion chemistry, Cl/Br ratios, Sr and B isotopes. It is mixed with fresh-brackish groundwater dominated by water-silicate interaction. This low salinity end-member (TDS from 0.3-10 g · l -1) shows radiogenic 87Sr/ 86Sr ratios ranging from 0.70910 to 0.71030 and low δ 11B values between 7.4 and 16.5‰ vs. NBS951. Two halite samples and a borate sample from the unaltered parts of the diapir show 87Sr/ 86Sr ratios from 0.70696 to 0.70868 and δ 11B values of 20.8 and 27.7‰. Brine (TDS from 100-328 g/l) Sr isotope ratios, ranging from 0.70758 to 0.70788, lie in the uppermost range of late Permian ocean waters and are within the range of halite. The δ 11B values of the brines vary between 25.1‰ to 33.5‰, which is close to the range of solid salt but well below those of evaporating present-day sea water. B isotope composition is thus compatible with salt dissolution rather than with residual evaporite brines. The chemistry and isotope characteristics of the brine end-member derived from halite dissolution are not significantly modified by subsequent

  7. Strontium isotopic signatures of the streams and lakes of Taylor Valley, Southern Victoria Land, Antarctica: Chemical weathering in a polar climate

    USGS Publications Warehouse

    Lyons, W.B.; Nezat, C.A.; Benson, L.V.; Bullen, T.D.; Graham, E.Y.; Kidd, J.; Welch, K.A.

    2002-01-01

    We have collected and analyzed a series of water samples from three closed-basin lakes (Lakes Bonney, Fryxell, and Hoare) in Taylor Valley, Antarctica, and the streams that flow into them. In all three lakes, the hypolimnetic waters have different 87Sr/86Sr ratios than the surface waters, with the deep water of Lakes Fryxell and Hoare being less radiogenic than the surface waters. The opposite occurs in Lake Bonney. The Lake Fryxell isotopic ratios are lower than modern-day ocean water and most of the whole-rock ratios of the surrounding geologic materials. A conceivable source of Sr to the system could be either the Cenozoic volcanic rocks that make up a small portion of the till deposited in the valley during the Last Glacial Maximum or from marble derived from the local basement rocks. The more radiogenic ratios from Lake Bonney originate from ancient salt deposits that flow into the lake from Taylor Glacier and the weathering of minerals with more radiogenic Sr isotopic ratios within the tills. The Sr isotopic data from the streams and lakes of Taylor Valley strongly support the notion documented by previous investigators that chemical weathering has been, and is currently, a major process in determining the overall aquatic chemistry of these lakes in this polar desert environment.

  8. Interpretation of the origin of massive replacive dolomite within atolls and submerged carbonate platforms: strontium isotopic signature ODP Hole 866A, Resolution Guyot, Mid-Pacific Mountains

    NASA Astrophysics Data System (ADS)

    Flood, P. G.; Fagerstrom, J. A.; Rougerie, F.

    1996-01-01

    Endo-upwelling is a geothermally driven convective process operating within the upper part of the volcanic foundation and overlying carbonate pile, in atolls and guyots. By this process deep oceanic water, rich in CO 2 and dissolved nitrates, phosphates and silicates is drawn into the pile, circulates slowly upward through the porous-permeable carbonate interior and emerges at either the reef crest or lagoon on atolls to support the primary productivity of the surficial communities, or towards the interior of the platform surface on guyots. Continuous operation of the endo-upwelling process requires: (a) heat from the volcanic foundation; (b) an external impermeable apron on the submerged flanks to confine the convective flow within the pile; and (c) a porous cap from which water exiting the plumbing system returns to the ocean. At ODP Hole 866A on Resolution Guyot, Mid-Pacific Mountains, the Sr isotopic signature of massive white-coloured, coarsely crystalline dolomite indicates a considerable time delay of approximately 100 Ma between carbonate deposition and dolomitization. This time delay is determined by comparing the Sr isotopic value of the dolomite and the time that ocean seawater displayed a similar Sr isotopic value. This interpretation of the Sr isotopic values assumes that all of the Sr is viewed as coming from seawater and none from any precursor limestone. The massive white replacement dolomite from Resolution Guyot possibly provides confirmation of the origin of dolomite by way of thermally driven convective flow within submerged carbonate platforms. Endo-upwelling seawater probably enters the carbonate pile at some depth, thermally circulates upwards, and produces carbonate dissolution and could conceivably produce massive dolomite replacement.

  9. USGS-NoGaDat - A global dataset of noble gas concentrations and their isotopic ratios in volcanic systems

    USGS Publications Warehouse

    Abedini, Atosa A.; Hurwitz, S.; Evans, William C.

    2006-01-01

    The database (Version 1.0) is a MS-Excel file that contains close to 5,000 entries of published information on noble gas concentrations and isotopic ratios from volcanic systems in Mid-Ocean ridges, ocean islands, seamounts, and oceanic and continental arcs (location map). Where they were available we also included the isotopic ratios of strontium, neodymium, and carbon. The database is sub-divided both into material sampled (e.g., volcanic glass, different minerals, fumarole, spring), and into different tectonic settings (MOR, ocean islands, volcanic arcs). Included is also a reference list in MS-Word and pdf from which the data was derived. The database extends previous compilations by Ozima (1994), Farley and Neroda (1998), and Graham (2002). The extended database allows scientists to test competing hypotheses, and it provides a framework for analysis of noble gas data during periods of volcanic unrest.

  10. Measuring Isotope Ratios Across the Solar System

    NASA Technical Reports Server (NTRS)

    Webster, Chris R.; Mahaffy, Paul R.

    2012-01-01

    Stable isotope ratios in C, H, N, O and S are powerful indicators of a wide variety of planetary geophysical processes that can identify origin, transport, temperature history, radiation exposure, atmospheric escape, environmental habitability and biology [1]. For the Allan Hills 84001 meteorite, for example, the (sup 1)(sup 3)C/(sup 1)(sup 2)C ratio identifies it as a Mars (SNC) meteorite; the ??K/??Ar ratio tells us the last time the rock cooled to solid, namely 4 Gya; isotope ratios in (sup 3)He, (sup 2)(sup 1)Ne and (sup 3)?Ar show it was in space (cosmic ray exposure) for 10-20 million years; (sup 1)?C dating that it sat in Antarctica for 13,000 years before discovery; and clumped isotope analysis of (sup 1)?O(sup 1)(sup 3)C(sup 1)?O in its carbonate that it was formed at 18+/-4 ?C in a near-surface aqueous environment [2]. Solar System Formation

  11. Isotopic fractionation of tritium in biological systems.

    PubMed

    Le Goff, Pierre; Fromm, Michel; Vichot, Laurent; Badot, Pierre-Marie; Guétat, Philippe

    2014-04-01

    Isotopic fractionation of tritium is a highly relevant issue in radiation protection and requires certain radioecological considerations. Sound evaluation of this factor is indeed necessary to determine whether environmental compartments are enriched/depleted in tritium or if tritium is, on the contrary, isotopically well-distributed in a given system. The ubiquity of tritium and the standard analytical methods used to assay it may induce biases in both the measurement and the signification that is accorded to the so-called fractionation: based on an exhaustive review of the literature, we show how, sometimes large deviations may appear. It is shown that when comparing the non-exchangeable fraction of organically bound tritium (neOBT) to another fraction of tritium (e.g. tritiated water) the preparation of samples and the measurement of neOBT reported frequently led to underestimation of the ratio of tritium to hydrogen (T/H) in the non-exchangeable compartment by a factor of 5% to 50%. In the present study, corrections are proposed for most of the biological matrices studied so far. Nevertheless, the values of isotopic fractionation reported in the literature remain difficult to compare with each other, especially since the physical quantities and units often vary between authors. Some improvements are proposed to better define what should encompass the concepts of exchangeable and non-exchangeable fractions.

  12. Measuring Isotope Ratios Across the Solar System

    NASA Technical Reports Server (NTRS)

    Webster, Chris R.; Mahaffy, Paul R.

    2012-01-01

    Stable isotope ratios in C, H, N, O and S are powerful indicators of a wide variety of planetary geophysical processes that can identify origin, transport, temperature history, radiation exposure, atmospheric escape, environmental habitability and biology [1]. For the Allan Hills 84001 meteorite, for example, the (sup 1)(sup 3)C/(sup 1)(sup 2)C ratio identifies it as a Mars (SNC) meteorite; the ??K/??Ar ratio tells us the last time the rock cooled to solid, namely 4 Gya; isotope ratios in (sup 3)He, (sup 2)(sup 1)Ne and (sup 3)?Ar show it was in space (cosmic ray exposure) for 10-20 million years; (sup 1)?C dating that it sat in Antarctica for 13,000 years before discovery; and clumped isotope analysis of (sup 1)?O(sup 1)(sup 3)C(sup 1)?O in its carbonate that it was formed at 18+/-4 ?C in a near-surface aqueous environment [2]. Solar System Formation

  13. Thermochemistry of perovskites in the lanthanum-strontium-manganese-iron oxide system

    NASA Astrophysics Data System (ADS)

    Marinescu, Cornelia; Vradman, Leonid; Tanasescu, Speranta; Navrotsky, Alexandra

    2015-10-01

    The enthalpies of formation from binary oxides of perovskites (ABO3) based on lanthanum strontium manganite La(Sr)MnO3 (LSM) and lanthanum strontium ferrite La(Sr)FeO3 (LSF) and mixed lanthanum strontium manganite ferrite La(Sr)Mn(Fe)O3 (LSMF) were measured by high temperature oxide melt solution calorimetry. Using iodometric titration, the oxygen content was derived. The perovskites with A-site cation deficiency have greater oxygen deficiency than the corresponding A-site stoichiometric series. Stability of LSMF decreases with increasing iron content. Increasing oxygen deficiency clearly destabilizes the perovskites. The results suggest an enthalpy of oxygen incorporation that is approximately independent of composition. 0.35La2O3 (xl, 25 °C)+Mn2O3 (xl, 25 °C)+0.3SrO (xl, 25 °C)+Fe2O3 (xl, 25 °C)+O2 (g, 25 °C)→La0.7Sr0.3Mn1-yFeyO3-δ (xl, 25 °C). (b) ∆ Hf,ox* (La0.7Sr0.3Mn1-yFeyO3-δ) .0.35 La2O3 (xl, 25 ººC) + (0.7-y+ 2δ)/2 Mn2O3 (xl, 25 ºC) + 0.3 SrO (xl, 25 ºC) + y/2Fe2O3 (xl, 25 ºC) + (0.3-2δ) MnO2 (xl, 25 ºC)→La0.7Sr0.3Mn1-yFeyO3-δ (xl, 25 ºC).

  14. A compact atomic beam based system for Doppler-free laser spectroscopy of strontium atoms

    NASA Astrophysics Data System (ADS)

    Verma, Gunjan; Vishwakarma, Chetan; Dharmadhikari, C. V.; Rapol, Umakant D.

    2017-03-01

    We report the construction of a simple, light weight, and compact atomic beam spectroscopy cell for strontium atoms. The cell is built using glass blowing technique and includes a simple titanium sublimation pump for the active pumping of residual and background gases to maintain ultra-high vacuum. A commercially available and electrically heated dispenser source is used to generate the beam of Sr atoms. We perform spectroscopy on the 5 s2S10 →5 s 5 pP11 transition to obtain a well resolved Doppler free spectroscopic signal for frequency stabilization of the laser source. This design can be easily extended to other alkali and alkaline earth metals.

  15. Impact of kinetic isotope effects in isotopic studies of metabolic systems.

    PubMed

    Millard, Pierre; Portais, Jean-Charles; Mendes, Pedro

    2015-09-26

    Isotope labeling experiments (ILEs) are increasingly used to investigate the functioning of metabolic systems. Some enzymes are subject to kinetic isotope effects (KIEs) which modulate reaction rates depending on the isotopic composition of their substrate(s). KIEs may therefore affect both the propagation of isotopes through metabolic networks and their operation, and ultimately jeopardize the biological value of ILEs. However, the actual impact of KIEs on metabolism has never been investigated at the system level. First, we developed a framework which integrates KIEs into kinetic and isotopic models of metabolism, thereby accounting for their system-wide effects on metabolite concentrations, metabolic fluxes, and isotopic patterns. Then, we applied this framework to assess the impact of KIEs on the central carbon metabolism of Escherichia coli in the context of (13)C-ILEs, under different situations commonly encountered in laboratories. Results showed that the impact of KIEs strongly depends on the label input and on the variable considered but is significantly lower than expected intuitively from measurements on isolated enzymes. The global robustness of both the metabolic operation and isotopic patterns largely emerge from intrinsic properties of metabolic networks, such as the distribution of control across the network and bidirectional isotope exchange. These results demonstrate the necessity of investigating the impact of KIEs at the level of the entire system, contradict previous hypotheses that KIEs would have a strong effect on isotopic distributions and on flux determination, and strengthen the biological value of (13)C-ILEs. The proposed modeling framework is generic and can be used to investigate the impact of all the isotopic tracers ((2)H, (13)C, (15)N, (18)O, etc.) on different isotopic datasets and metabolic systems. By allowing the integration of isotopic and metabolomics data collected under stationary and/or non-stationary conditions, it may

  16. Application of TREECS Modeling System to Strontium-90 for Borschi Watershed near Chernobyl, Ukraine.

    PubMed

    Johnson, Billy E; Dortch, Mark S

    2014-05-01

    The Training Range Environmental Evaluation and Characterization System (TREECS™) (http://el.erdc.usace.army.mil/treecs/) is being developed by the U.S. Army Engineer Research and Development Center (ERDC) for the U.S. Army to forecast the fate of munitions constituents (MC) (such as high explosives (HE) and metals) found on firing/training ranges, as well as those subsequently transported to surface water and groundwater. The overall purpose of TREECS™ is to provide environmental specialists with tools to assess the potential for MC migration into surface water and groundwater systems and to assess range management strategies to ensure protection of human health and the environment. The multimedia fate/transport models within TREECS™ are mathematical models of reduced form (e.g., reduced dimensionality) that allow rapid application with less input data requirements compared with more complicated models. Although TREECS™ was developed for the fate of MC from military ranges, it has general applicability to many other situations requiring prediction of contaminant (including radionuclide) fate in multi-media environmental systems. TREECS™ was applied to the Borschi watershed near the Chernobyl Nuclear Power Plant, Ukraine. At this site, TREECS™ demonstrated its use as a modeling tool to predict the fate of strontium 90 ((90)Sr). The most sensitive and uncertain input for this application was the soil-water partitioning distribution coefficient (Kd) for (90)Sr. The TREECS™ soil model provided reasonable estimates of the surface water export flux of (90)Sr from the Borschi watershed when using a Kd for (90)Sr of 200 L/kg. The computed export for the year 2000 was 0.18% of the watershed inventory of (90)Sr compared to the estimated export flux of 0.14% based on field data collected during 1999-2001. The model indicated that assumptions regarding the form of the inventory, whether dissolved or in solid phase form, did not appreciably affect export rates

  17. Open system diagenesis and the los of provenance signatures: isotopic and elemental data from sandstones, Frio Formation, south Texas

    SciTech Connect

    Land, L.S.; Mack, L.E.; Milliken, K.L. ); MacPherson, G.L. )

    1990-05-01

    Oligocene Frio sandstones in which detrital feldspars are completely altered typically contain authigenic minerals that exceed 30% of the rock volume. Elemental and isotopic analyses of whole rocks show that authigenesis is accompanied by both gain and loss of material. Subsurface sandstones for elemental and isotopic analysis were sampled from approximately 3,000-14,000 ft (0.9-4.3 km). Over this depth range, dissolution and minor albitization of detrital K-feldspar is accompanied by loss of 2 to 3 wt.% of K{sub 2}O from the whole rock. Loss of about 50% of the initial strontium also correlates with alteration of detrital feldspars. {sup 87}Sr/{sup 86}Sr for whole-rock and silicate fractions change with depth as strontium characteristic of the detrital fraction is replaced by more radiogenic strontium derived from deeper in the basin. Aluminum, titanium, phosphorous, manganese, and barium also exhibit trends compatible with net export, but uncertainties about initial variation remain. Trends for silicon, sodium, iron, boron, and lithium are equivocal. Magnesium gain accompanies precipitation of authigenic chlorite. Whole-rock calcium values are dominated by calcite that includes both detrital and authigenic components. Significant dissolution of the detrital carbonate component does not occur, and calcium in authigenic carbonate exceeds by about five times the calcium released during destruction of detrital silicates, thus requiring considerable calcium and CO{sub 2} import. Material transfer on the scale observed suggests that simple burial diagenesis is not a closed-system process for several major elements and introduces a major obstacle to the use of elemental data for provenance interpretation.

  18. Strontium-89 and Strontium-90 Levels in Breast Milk and in Mineral-Supplement Preparations

    PubMed Central

    Jarvis, Anita A.; Brown, John R.; Tiefenbach, Bella

    1963-01-01

    Strontium-90, strontium-89 and S.U. values were determined in human milk before and after the resumption of atmospheric nuclear testings in 1961, and the levels were compared to cows' milk values reported during the same time. S.U.90 levels in human milk were approximately one-fifth of those found in cows' milk. Assuming an average dietary intake of 11-13 S.U.90 during the period tested, the mean strontium/calcium ratio of 1.78 found in human milk represents an Observed Ratio milk-diet of approximately 0.14-0.16. Although strontium-89 was present in cows' milk already in September 1961, it did not appear in human milk until November 1961. It seems, therefore, that there was a two-month lag period between the appearance of fresh fallout in cows' milk and human milk. Calcium-supplement mineral preparations used by pregnant and lactating women were tested to find their strontium-89, strontium-90 and S.U. levels, because strontium isotopes, if present in these products, will be transferred to the fetus and to breast-fed infants. The compounds tested had S.U.90 levels of 0.13-2.62; in none of the preparations was Sr89 present. PMID:14041888

  19. Neodymium, strontium and chromium isotopic studies of the LEW86010 and Angra dos Reis meteorites and the chronology of the angrite parent body

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Bansal, B.; Wiesmann, H.; Shih, C.-Y.

    1994-01-01

    Neodymium, stontium, and chromium isotopic studies of the LEW86010 angrite established its absolute age and the formation interval between its crystallization and condensation of Allende CAIs from the solar nebula. Pyroxene and phosphate were found to contain approximately 8% of its Sm and Nd inventory. A conventional Sm-147-Nd-143 isochron yielded an age of 4.53 +/- 0.04 Ga (2 sigma and Epsilon(sub Nd sup 143)) = 0.45 +/- 1.1. An Sm-146-Nd-142 isochron gives initial Sm-146/Sm-144 = 0.0076 +/- 0.0009 and Epsilon (sub Nd sup 142) = -2.5 +/- 0.4. The Rb-Sr analyses give initial Sr-87/Sr-86 Iota(sub Sr sup 87) = 0.698972 +/- 8 and 0.698970 +/- 18 for LEW and ADOR, respectively, relative to Sr-87/Sr-86 = 0.71025 for NBS987. The difference, Delta Iota(sub Sr Sup 87), between Iota (sub sr sup 87) for the angrites and literature values for Allende CAIs, corresponds to approximately Ma of growth in a solar nebula with a CI chondrite value of Rb-87/Sr-86 = 0.91, or approximately 5 Ma in a nebula with solar photospheric Rb-87/Sr-86 = 1.51. Excess Cr-53 from extinct Mn-53(t(sub 1/2) = 3.7 Ma)in LEW86010 corresponds to initial Mn-53/Mn-55 = 4.4 +/- 1.0 x 10(exp -5) for the inclusions as previously reported by the Paris group (Birck and Allegre, 1988). The Sm-146/Sm-144 value found for LEW86010 corresponds to solar system initial (Sm-146/Sm-144) = 0.0080 +/- 0.0009 for crystallization 8 Ma after Allende, the difference between Pb-Pb ages of angrites and Allende, or 0.0086 +/- 0.0009 for crystallation 18 Ma after Allende, using the Mn-Cr formation interval. The isotopic data are discussed in the context of a model in which an undifferentiated 'chondritic' parent body formed from the solar nebula approximately Ma after Allende CAIs and subsequently underwent differentiation accompanied by loss of volatiles. Parent bodies with Rb/Sr similar to that of CI, CM, or CO chondrites could satisfy the Cr and Sr isotopic systematics. If the angrite parent body had Rb/Sr similar to that of

  20. Neodymium, strontium and chromium isotopic studies of the LEW86010 and Angra dos Reis meteorites and the chronology of the angrite parent body

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Bansal, B.; Wiesmann, H.; Shih, C.-Y.

    1994-01-01

    Neodymium, stontium, and chromium isotopic studies of the LEW86010 angrite established its absolute age and the formation interval between its crystallization and condensation of Allende CAIs from the solar nebula. Pyroxene and phosphate were found to contain approximately 8% of its Sm and Nd inventory. A conventional Sm-147-Nd-143 isochron yielded an age of 4.53 +/- 0.04 Ga (2 sigma and Epsilon(sub Nd sup 143)) = 0.45 +/- 1.1. An Sm-146-Nd-142 isochron gives initial Sm-146/Sm-144 = 0.0076 +/- 0.0009 and Epsilon (sub Nd sup 142) = -2.5 +/- 0.4. The Rb-Sr analyses give initial Sr-87/Sr-86 Iota(sub Sr sup 87) = 0.698972 +/- 8 and 0.698970 +/- 18 for LEW and ADOR, respectively, relative to Sr-87/Sr-86 = 0.71025 for NBS987. The difference, Delta Iota(sub Sr Sup 87), between Iota (sub sr sup 87) for the angrites and literature values for Allende CAIs, corresponds to approximately Ma of growth in a solar nebula with a CI chondrite value of Rb-87/Sr-86 = 0.91, or approximately 5 Ma in a nebula with solar photospheric Rb-87/Sr-86 = 1.51. Excess Cr-53 from extinct Mn-53(t(sub 1/2) = 3.7 Ma)in LEW86010 corresponds to initial Mn-53/Mn-55 = 4.4 +/- 1.0 x 10(exp -5) for the inclusions as previously reported by the Paris group (Birck and Allegre, 1988). The Sm-146/Sm-144 value found for LEW86010 corresponds to solar system initial (Sm-146/Sm-144) = 0.0080 +/- 0.0009 for crystallization 8 Ma after Allende, the difference between Pb-Pb ages of angrites and Allende, or 0.0086 +/- 0.0009 for crystallation 18 Ma after Allende, using the Mn-Cr formation interval. The isotopic data are discussed in the context of a model in which an undifferentiated 'chondritic' parent body formed from the solar nebula approximately Ma after Allende CAIs and subsequently underwent differentiation accompanied by loss of volatiles. Parent bodies with Rb/Sr similar to that of CI, CM, or CO chondrites could satisfy the Cr and Sr isotopic systematics. If the angrite parent body had Rb/Sr similar to that of

  1. Bacterially Induced Calcite Precipitation and Strontium Co-Precipitation under Flow Conditions in a Porous Media System

    NASA Astrophysics Data System (ADS)

    Gerlach, R.; Mitchell, A. C.; Schultz, L.; Cunningham, A.

    2009-12-01

    The process of in situ carbonate mineral formation has implications in many environmental applications, including, but not limited to aquifer decontamination, enhancement of soil stability, and carbon capture and storage (CCS). The high stability of carbonates and the potential for co-precipitation of contaminants within carbonates are attractive attributes for several potential engineering applications. Ureolytic precipitation of calcium and strontium carbonates by Sporosarcina pasteurii was examined in two-dimensional flat plate porous media reactors. Complete reactor plugging due to biofilm formation and calcium carbonate precipitation was achieved in Sr-free systems after 14 hours and in Sr-inclusive systems after 15 hours. Comparison of the reactor influent and effluent after 11 hours indicated that Ca2+ concentrations in the Sr-free reactor effluent were reduced to approximately 0.48% of the influent concentration while the Ca2+ and Sr2+ concentrations of the Sr-inclusive effluent were reduced to 0.64% and 2.34% of the influent concentration indicating a slight inhibitory effect of strontium on calcium carbonate precipitation . Despite this slight inhibition, more than 98% of the Ca2+ entering the reactors was precipitated. Calcite was identified as the main mineral formed and a larger mean crystal size and density were observed near the reactor influent. Homogenous partition coefficients calculated from extracted precipitates suggest higher Sr2+ partitioning near the inlet region, where higher precipitation kinetics exist. Results confirm the possibility of effective calcite-based co-precipitation of Sr2+ under flow conditions and contributes towards the development of field-scale calcium carbonate mineral-based immobilization strategies.

  2. Bacterially Induced Calcite Precipitation and Strontium Co-Precipitation under Flow Conditions in a Porous Media System

    NASA Astrophysics Data System (ADS)

    Gerlach, Robin; Mitchell, Andrew C.; Schultz, Logan N.; Cunningham, Al B.

    2010-05-01

    The process of in situ carbonate mineral formation has implications in many environmental applications, including, but not limited to aquifer decontamination, enhancement of soil stability, and carbon capture and storage (CCS). The high stability of carbonates and the potential for co-precipitation of contaminants within carbonates are attractive attributes for several potential engineering applications. Ureolytic precipitation of calcium and strontium carbonates by Sporosarcina pasteurii was examined in two-dimensional flat plate porous media reactors. Complete reactor plugging due to biofilm formation and calcium carbonate precipitation was achieved in Sr-free systems after 14 hours and in Sr-inclusive systems after 15 hours. Comparison of the reactor influent and effluent after 11 hours indicated that Ca2+ concentrations in the Sr-free reactor effluent were reduced to approximately 0.48% of the influent concentration while the Ca2+ and Sr2+ concentrations of the Sr-inclusive effluent were reduced to 0.64% and 2.34% of the influent concentration indicating a slight inhibitory effect of strontium on calcium carbonate precipitation . Despite this slight inhibition, more than 98% of the Ca2+ entering the reactors was precipitated. Calcite was identified as the main mineral formed and a larger mean crystal size and density were observed near the reactor influent. Homogenous partition coefficients calculated from extracted precipitates suggest higher Sr2+ partitioning near the inlet region, where higher precipitation kinetics exist. Results confirm the possibility of effective calcite-based co-precipitation of Sr2+ under flow conditions and contributes towards the development of field-scale calcium carbonate mineral-based immobilization strategies.

  3. Ca isotope fractionation in a high-alkalinity lake system: Mono Lake, California

    NASA Astrophysics Data System (ADS)

    Nielsen, Laura C.; DePaolo, Donald J.

    2013-10-01

    Precipitation of calcium carbonate minerals from aqueous solutions causes surface-controlled kinetic stable Ca isotope fractionation. The magnitude of fractionation depends on the relative rates of ion attachment to and detachment from the mineral surface, which in turn is predicted to depend on both the saturation state and the solution stoichiometry or the Ca:CO32- activity ratio. Experimental studies have not directly investigated the effects of varying solution stoichiometry on calcium isotope partitioning during calcite or aragonite growth, but natural alkaline lake systems such as Mono Lake, California provide a test bed for the hypothesized stoichiometry dependence. Mono Lake has a Ca:CO32- activity ratio of about 0.0001, seven orders of magnitude lower than ocean water and typical terrestrial freshwater. We present chemical and isotopic measurements of streams, springs, lake water, and precipitated carbonates from the Mono Basin that yield evidence of stoichiometry-dependent Ca isotope fractionation during calcite, aragonite and Mg-calcite precipitation from the alkaline lake water. To estimate the Ca isotope fractionation factors, it is necessary to characterize the lake Ca balance and constrain the variability of lake water chemistry both spatially and temporally. Streams and springs supply Ca to the lake, and a substantial fraction of this supply is precipitated along the lake shore to form tufa towers. Lake water is significantly supersaturated with respect to carbonate minerals, so CaCO3 also precipitates directly from the water column to form carbonate-rich bottom sediments. Growth rate inhibition by orthophosphate likely preserves the high degree of supersaturation in the lake. Strontium isotope ratios are used to estimate the proportions of fresh and alkaline lake water from which each solid carbonate sample precipitated. Carbonate minerals that precipitate directly from lake water (low Ca:CO32-) experience relatively large Ca isotope fractionation

  4. Microstructural, dielectric and magnetic properties of multiferroic composite system barium strontium titanate – nickel cobalt ferrite

    SciTech Connect

    Pahuja, Poonam Tandon, R. P.

    2015-05-15

    Multiferroic composites (1-x) Ba{sub 0.95}Sr{sub 0.05}TiO{sub 3} + (x) Ni{sub 0.8}Co{sub 0.2}Fe{sub 2}O{sub 4} (where x = 0.1, 0.2, 0.3, 0.4) has been prepared by solid state reaction method. X-ray diffraction analysis of the composite samples confirmed the presence of both barium strontium titanate (BST) and nickel cobalt ferrite (NCF) phases. FESEM images indicated the well dispersion of NCF grains among BST grains. Dielectric constant and loss of the composite samples decreases with increase in frequency following Maxwell-Wagner relaxation mechanism. Composite sample with highest ferrite content possesses highest values of remanent and saturation magnetization.

  5. Fractionation of Boron Isotopes in Icelandic Hydrothermal Systems

    SciTech Connect

    Aggarwal, J.K.; Palmer, M.R.

    1995-01-01

    Boron isotope ratios have been determined in a variety of different geothermal waters from hydrothermal systems across Iceland. Isotope ratios from the high temperature meteoric water recharged systems reflect the isotope ratio of the host rocks without any apparent fractionation. Seawater recharged geothermal systems exhibit more positive {delta}{sup 11}B values than the meteoric water recharged geothermal systems. Water/rock ratios can be assessed from boron isotope ratios in the saline hydrothermal systems. Low temperature hydrothermal systems also exhibit more positive {delta}{sup 11}B than the high temperature systems, indicating fractionation of boron due to adsorption of the lighter isotope onto secondary minerals. Fractionation of boron in carbonate deposits may indicate the level of equilibrium attained within the systems.

  6. Nuclear Volume Effects in Equilibrium Stable Isotope Fractionations of Hg, Tl and Pb Isotope Systems

    NASA Astrophysics Data System (ADS)

    Yang, S.; Liu, Y.

    2014-12-01

    Many evidences showed that heavy isotope systems could be significantly fractionated as the consequence of the nuclear volume effect (NVE) or so-called nuclear field shift effect. Here we investigate NVEs of Hg, Tl and Pb isotope systems by using quantum chemistry computational methods with careful evaluation on quantum relativistic effects via the Dirac's formalism of full-electron wavefunction. Our results generally agree with previous studies but with noticeable differences in many cases. With the unique NVE driving force, equilibrium 202Hg/198Hg and 205Tl/203Tl isotopes can be fractionated up to 3.94‰ and 2.78‰ at 0℃, respectively, showing potentially large equilibrium isotope fractionations can be expected for future studies of these two isotope systems. Moreover, the NVE causes large mass-independent fractionations (MIF) for odd-mass isotopes (e.g., ∆199NVHg and ∆201NVHg) and small MIFs for even-mass isotopes (e.g., ∆200NVHg). For Pb isotope system, NVEs induce isotope fractionations up to 1.62‰ (207Pb/206Pb) and 4.06‰ (208Pb/206Pb) at 0℃. However, contributions from classical mass-dependent driving force are small, about 0.1-0.5‰ for 207Pb/206Pb and 0.2-0.9‰ for 208Pb/206Pb. We find that Pb4+-bearing species can be significantly enriched heavy isotopes than Pb2+-bearing species. Comparing to Pb0, Pb2+-bearing species even enrich lighter Pb isotopes. A very strange and interesting thing is that the beta value of Pb2+-bearing species can be smaller than the unity (1.000). Similar thing has been found on Tl+-bearing species. This is an impossible and unexplained situation if only based on classical mass-dependent isotope fractionation theory (e.g., Bigeleisen-Mayer equation). The consequence is that the different direction of beta values of Pb2+-bearing species will let the Pb isotope fractionation even larger when they fractionate with Pb4+-bearing species. Moreover, NVEs also cause mass-independent fractionation (MIF) of odd 207Pb

  7. Strontium-containing, carbohydrate-based polymer networks as tooth-adherent systems for the treatment of dentine hypersensitivity.

    PubMed

    Jones, Dary K F; Andrews, Gavin P; Jones, David S

    2017-02-10

    This study describes the design/physicochemical properties of strontium-containing, mucoadhesive carbohydrate polymeric platforms, designed as treatments for dentine hypersensitivity. Interactive networks were composed of strontium chloride (10% w/w), one of two base polymers (sodium carboxymethylcellulose, NaCMC or hydroxyethylcellulose, HEC), polycarbophil (PC) and, when required, polyvinylpyrrolidone (PVP). The physicochemical properties were characterised using oscillatory and flow rheometry, texture profile analysis, mucoadhesion analysis and, additionally, the strontium release properties were examined. All platforms exhibited pseudoplastic flow. Increasing polymer concentrations increased network viscoelasticity, consistency, hardness, compressibility, gel strength, adhesiveness, mucoadhesion and, retarded strontium release. Principally zero-order strontium release was observed from all platforms. Incorporation of strontium reduced the network elasticity, consistency, hardness, compressibility, gel strength and mucoadhesion; HEC-based platforms being affected to a greater extent than NaCMC platforms. NaCMC-based platforms containing 10% strontium chloride, PVP (3% w/w) and PC (3% w/w) potentially displayed the correct balance of physicochemical properties for the treatment of dentine sensitivity.

  8. Stable Chlorine Isotope Study: Application to Early Solar System Materials

    NASA Technical Reports Server (NTRS)

    Mala,ira. M/; Nyquist, L. E.; Reese, Y.; Shih, C-Y; Fujitani, T.; Okano, O.

    2010-01-01

    A significantly large mass fractionation between two stable chlorine isotopes is expected during planetary processes In addition, in view of the isotopic heterogeneity of other light elements, the chlorine isotopes can potentially be used as a tracer for the origins and evolutionary processes of early solar system materials. Due to analytical difficulties, however, current chlorine isotope studies on planetary materials are quite controversial among IRMS (gas source mass spectrometry) and/or TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1-3]. Although a cross-calibration of IRMS and TIMS indicates that both techniques are sufficiently consistent with each other [4], some authors have claimed that the Cl-37/Cl-35 ratio of geological samples obtained by TIMS technique are, in general, misleadingly too high and variable compared to those of IRMS [3]. For example, almost no differences of Cl isotope composition were observed among mantle materials and carbonaceous meteorites by [3]. On the other hand, according to more recent IRMS work [2], significant Cl isotope variations are confirmed for mantle materials. Therefore, additional careful investigation of Cl isotope analyses are now required to confirm real chlorine isotope variations for planetary materials including carbonaceous chondrites [5]. A significantly large mass fractionation between two stable chlorine isotopes is expected during planetary processes In addition, in view of the isotopic heterogeneity of other light elements, the chlorine isotopes can potentially be used as a tracer for the origins and evolutionary processes of early solar system materials. Due to analytical difficulties, however, current chlorine isotope studies on planetary materials are quite controversial among IRMS (gas source mass spectrometry) and/or TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1-3]. Although a cross-calibration of IRMS and TIMS indicates that both techniques are sufficiently consistent with each

  9. Stable light isotope biogeochemistry of hydrothermal systems

    NASA Technical Reports Server (NTRS)

    Des Marais, D. J.

    1996-01-01

    The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of hydrothermal systems. Hydrothermal alteration of the 18O/16O and D/H values of minerals can be used to detect fossil systems and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of hydrothermal fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at hydrothermal temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2.

  10. Stable light isotope biogeochemistry of hydrothermal systems.

    PubMed

    Des Marais, D J

    1996-01-01

    The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of hydrothermal systems. Hydrothermal alteration of the 18O/16O and D/H values of minerals can be used to detect fossil systems and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of hydrothermal fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at hydrothermal temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2.

  11. System and method for high precision isotope ratio destructive analysis

    DOEpatents

    Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

    2013-07-02

    A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

  12. Radiogenic Isotope Constraints on Fluid Sources in the Yellowstone Hydrothermal System

    NASA Astrophysics Data System (ADS)

    Scott, S. R.; Sims, K. W. W.; Role, A.; Shock, E.; Boyd, E. S.

    2015-12-01

    For decades, researchers in Yellowstone National Park (YNP) have used major and trace element and light stable isotope geochemistry to evaluate fluid sources and geochemical reactions in the Yellowstone hydrothermal system. However, the results can be affected by mixing, boiling and vapor-phase separation. We present new strontium (Sr), neodymium (Nd), and lead (Pb) isotopic data from hydrothermal waters and fumarole condensates that allow us to evaluate fluid sources independent of near-surface mixing and boiling. Our sample set was selected to explore the range of fluid compositions found in the Yellowstone hydrothermal system, including waters/fluids that are thought to be exclusively meteoric, exclusively from the deep hydrothermal system, and those which are a mixture of these end members and/or that have been influenced by various hydrothermal processes such as boiling or gas/water interaction. We have identified at least three isotopic endmembers that persist in various features throughout the YNP hydrothermal system. The first endmember has relatively unradiogenic Pb with Sr, Nd, and Pb isotopic compositions that are consistent with Yellowstone basalts and rhyolites. This endmember is typified by low pH features. We interpret this fluid as surface water and shallow groundwater that has interacted with volcanic rocks associated with the YNP magmatic system, with the acidity derived from oxidation of volcanic gases. The second endmember has relatively radiogenic Pb, radiogenic Sr, and unradiogenic Nd. This endmember is typified by neutral pH features and near neutral fumarole condensates. We interpret this endmember to represent the hypothesized deep hydrothermal reservoir that interacts with and reflects the isotopic composition of the host rock. The third endmember contains radiogenic Pb, unradiogenic Nd, and unradiogenic Sr. We observe this endmember in neutral features, which are interpreted as hydrothermal waters (shallow, deep, or mixtures) that have

  13. Strontium ranelate in osteoporosis.

    PubMed

    Reginster, J-Y

    2002-01-01

    Strontium ranelate is composed of an organic moiety (ranelic acid) and of two atoms of stable non-radioactive strontium. In vitro, strontium ranelate increases collagen and non-collagenic proteins synthesis by mature osteoblast enriched cells. The effects of strontium ranelate on bone formation were confirmed as strontium ranelate enhanced pre-osteoblastic cells replication. The stimulation by strontium ranelate of the replication of osteoprogenitor cells and collagen as well as non-collagenic protein synthesis in osteoblasts provides substantial evidence to categorise SR ranelate as a bone forming agent. In the mouse calvaria culture system, SR ranelate induces a dose-dependent inhibition of labelled calcium release. The inhibitory effects of SR ranelate on bone resorption were close to those of salmon calcitonin. In the isolated rat osteoclast assay, a pre-incubation of bone slices with SR ranelate induced a dose-dependent inhibition of the bone resorbing activity of a treated rat osteoclast. SR ranelate also dose-dependently inhibited, in a chicken bone marrow culture, the expression of both CA II and the alpha-subunit of the vitronectin receptor. These effects showing that SR ranelate significantly affects bone resorption due to direct and/or matrix-mediated inhibition of osteoclast activity and also inhibits osteoclasts differentiation are compatible with the profile of an anti-resorptive drug. In normal rats, administration of SR ranelate induces an improvement in the mechanical properties of the humerus and/or the lumbar vertebra associated with a commensurate increase in bone dimension, shaft and volume. This was not related to any change in the stiffness, suggesting the absence of a mineralisation defect. After oral administration of SR ranelate in humans, the absolute bio-availability of SR ranelate is 27 % after a dose of 2g is given as sachets. The simultaneous intake of SR ranelate and calcium remarkably reduces the bio-availability of SR. SR ranelate

  14. Hazardous Waste Management System - Removal of Strontium Sulfide From the List of Hazardous Waste - Federal Register Notice, February 25, 1991

    EPA Pesticide Factsheets

    The Environmental Protection Agency is correcting an amendment to regulations under the Resource Conservation and Recovery Act (RCRA) to remove strontium sulfide (CAS No. 1314-96-1) from 40 CFR 261.33.

  15. Amino acid isotopic analysis in agricultural systems

    USDA-ARS?s Scientific Manuscript database

    A relatively new approach to stable isotopic analysis—referred to as compound-specific isotopic analysis (CSIA)—has emerged, centering on the measurement of 15N:14N ratios in amino acids (glutamic acid and phenylalanine). CSIA has recently been used to generate trophic position estimates among anima...

  16. Metal stable isotopes in low-temperature systems: A primer

    USGS Publications Warehouse

    Bullen, T.D.; Eisenhauer, A.

    2009-01-01

    Recent advances in mass spectrometry have allowed isotope scientists to precisely determine stable isotope variations in the metallic elements. Biologically infl uenced and truly inorganic isotope fractionation processes have been demonstrated over the mass range of metals. This Elements issue provides an overview of the application of metal stable isotopes to low-temperature systems, which extend across the borders of several science disciplines: geology, hydrology, biology, environmental science, and biomedicine. Information on instrumentation, fractionation processes, data-reporting terminology, and reference materials presented here will help the reader to better understand this rapidly evolving field.

  17. Injectable hybrid system for strontium local delivery promotes bone regeneration in a rat critical-sized defect model.

    PubMed

    Henriques Lourenço, Ana; Neves, Nuno; Ribeiro-Machado, Cláudia; Sousa, Susana R; Lamghari, Meriem; Barrias, Cristina C; Trigo Cabral, Abel; Barbosa, Mário A; Ribeiro, Cristina C

    2017-07-11

    Strontium (Sr) has been described as having beneficial influence in bone strength and architecture. However, negative systemic effects have been reported on oral administration of Sr ranelate, leading to strict restrictions in clinical application. We hypothesized that local delivery of Sr improves osteogenesis without eliciting detrimental side effects. Therefore, the in vivo response to an injectable Sr-hybrid system composed of RGD-alginate hydrogel cross-linked in situ with Sr and reinforced with Sr-doped hydroxyapatite microspheres, was investigated. The system was injected in a critical-sized bone defect model and compared to a similar Sr-free material. Micro-CT results show a trend towards higher new bone formed in Sr-hybrid group and major histological differences were observed between groups. Higher cell invasion was detected at the center of the defect of Sr-hybrid group after 15 days with earlier bone formation. Higher material degradation with increase of collagen fibers and bone formation in the center of the defect after 60 days was observed as opposed to bone formation restricted to the periphery of the defect in the control. These histological findings support the evidence of an improved response with the Sr enriched material. Importantly, no alterations were observed in the Sr levels in systemic organs or serum.

  18. Production of very-high- n strontium Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Ye, Shuzhen; Zhang, Xinyue; Killian, Thomas; Dunning, F.; Hiller, Moritz; Yoshida, Shuhei; Burgdoerfer, Joachim

    2013-05-01

    The production of very-high- n, n ~ 300, strontium Rydberg atoms is explored using a crossed laser-atom beam geometry. n1S0 and n1D2 states are created by two-photon excitation via the 5s5p 1P1 intermediate state using radiation at 461 and 413 nm. Rydberg series in the different strontium isotopes present in the beam can be selectively excited by tuning the 461 nm light allowing measurements of the isotope shifts in the series limits, that for 88Sr-86Sr being ~ + 210MHz, and that for 88Sr-84Sr being ~ + 440 MHz. Well-resolved Rydberg series can be seen for values of n approaching ~ 500. Photoexcitation spectra calculated using a two-active-electron model reproduce the relative strengths of the measured 1S0 and 1D2 lines. The surprisingly large photoexcitation rates provide new opportunities to study quasi-stable two-electron excited states and to explore the behavior of strongly coupled Rydberg systems at high n. Research supported by the NSF, the Robert A. Welch Foundation and the FWF (Austria).

  19. The isotopic homogeneity in the early solar system: Revisiting the CAI oxygen isotopic anomaly

    NASA Astrophysics Data System (ADS)

    Ozima, M.; Yamada, A.

    2009-12-01

    Since the first discovery of the mass-independently fractionated oxygen isotopes in anhydrous, high temperature Ca-Al rich inclusion minerals in carbonaceous meteorites (CAIs) by Clayton et al. (1), their common occurrence in primitive meteorites has generally been regarded to reflect some fundamental process prevalent in the early solar nebula. The CAI oxygen isotopic composition is uniquely characterized by (i) large mass independent isotopic fractionation and (ii) their isotopic data in an oxygen three isotope plot (δ17O - δ18O (δ17O ≡ {(17O/16O)/(17O/16O)SMOW - 1} × 1000) yield nearly a straight line with a slope 1.0. In establishing these characteristics, ion microprobe analyses has played a central role, especially an isotopic mapping technique (isotopography) was crucial (e.g., 2). The extraordinary oxygen isotopic ratio in CAIs is widely attributed to the self-shielding absorption of UV radiation in CO, one of the dominant chemical compounds in the early solar nebula (3). However, the self-shielding scenario necessarily leads to the unusual prediction that a mean solar oxygen isotopic composition differs from most of planetary bodies including Earth, Moon, and Mars. If the self-shielding process were indeed responsible to the CAI oxygen isotopic anomaly, this would require a fundamental revision of the current theory of the origin of the solar system, which generally assumes the initial total vaporization of nebula material to give rise to isotopic homogenization. The GENESIS mission launched in 2001(4), which collected oxygen in the solar wind was hoped to resolve the isotopic composition of the Sun. However, because of difficulties in correcting for instrumental and more importantly for intrinsic isotopic fractionation between the SW and the Sun, a final answer is yet to be seen (5). Here, we show on the basis of the oxygen isotopic fractionation systematics that the self shielding hypothesis cannot explain the key characteristics of the CAI oxygen

  20. Quantification of isotopic turnover in agricultural systems

    NASA Astrophysics Data System (ADS)

    Braun, A.; Auerswald, K.; Schnyder, H.

    2012-04-01

    The isotopic turnover, which is a proxy for the metabolic rate, is gaining scientific importance. It is quantified for an increasing range of organisms, from microorganisms over plants to animals including agricultural livestock. Additionally, the isotopic turnover is analyzed on different scales, from organs to organisms to ecosystems and even to the biosphere. In particular, the quantification of the isotopic turnover of specific tissues within the same organism, e.g. organs like liver and muscle and products like milk and faeces, has brought new insights to improve understanding of nutrient cycles and fluxes, respectively. Thus, the knowledge of isotopic turnover is important in many areas, including physiology, e.g. milk synthesis, ecology, e.g. soil retention time of water, and medical science, e.g. cancer diagnosis. So far, the isotopic turnover is quantified by applying time, cost and expertise intensive tracer experiments. Usually, this comprises two isotopic equilibration periods. A first equilibration period with a constant isotopic input signal is followed by a second equilibration period with a distinct constant isotopic input signal. This yields a smooth signal change from the first to the second signal in the object under consideration. This approach reveals at least three major problems. (i) The input signals must be controlled isotopically, which is almost impossible in many realistic cases like free ranging animals. (ii) Both equilibration periods may be very long, especially when the turnover rate of the object under consideration is very slow, which aggravates the first problem. (iii) The detection of small or slow pools is improved by large isotopic signal changes, but large isotopic changes also involve a considerable change in the input material; e.g. animal studies are usually carried out as diet-switch experiments, where the diet is switched between C3 and C4 plants, since C3 and C4 plants differ strongly in their isotopic signal. The

  1. Carbon, oxygen and strontium isotopic constraints on fluid sources, temperatures and biogeochemical processes during the formation of seep carbonates - Secchia River site, Northern Apennines

    NASA Astrophysics Data System (ADS)

    Viola, Irene; Capozzi, Rossella; Bernasconi, Stefano M.; Rickli, Jörg

    2017-07-01

    Understanding authigenic seep carbonate formation provides clues for hydrocarbon exploration and insights into contributions to gas budgets of marine environments and the atmosphere. Seep carbonates discovered in the outcropping succession along the Secchia riverbanks (near Modena, Italy) belong to the Argille Azzurre Formation of Early Pleistocene age deposited in an upper shelf environment overlying the Miocene foredeep successions, which include hydrocarbon fields. The fluid migration from the hydrocarbon fields, up to the surface, is presently active on land and started in the marine succession during the Late Miocene. Authigenic globular carbonate concretions and carbonate chimneys are interspersed along the strata throughout the section. A comprehensive geochemical characterisation of the carbonates has been carried out to understand the processes leading to their formation. The carbonate concretions are the record of past hydrocarbon vents linked to the Miocene petroleum system of the Northern Apennines. The samples are composed of > 50% microcrystalline dolomite. The δ13C signatures identify two groups in the samples according to different type of formation processes. Globular concretions have positive values that suggest an influence of CO2 associated to secondary methanogenesis due to microbial degradation of higher hydrocarbons. The analysed chimney, with negative δ13C values, is interpreted as former conduit where carbonate precipitation is promoted by Anaerobic Oxidation of Methane coupled with Sulfate Reduction. The δ18O range, coupled with 87/86Sr signatures, indicate that the contribution of deep connate water from the Miocene reservoirs is up to 23% during the formation of the globular concretions. The connate water occurrence is also documented by higher ambient temperatures. The different isotope signatures in seep carbonates result from the relative contribution of the recognised gas and water components, linked to different plumbing systems

  2. Sulphur isotope applications in two Philippine geothermal systems

    SciTech Connect

    Bayon, F.E.B.

    1996-12-31

    A general and very preliminary study of sulphur isotope geochemistry is presented in this paper. Data from the Mt. Apo and Palinpinon geothermal fields are used to demonstrate the use of sulphur isotopes in geothermometry and correlation of sulphur species. Sulphur and oxygen isotope geothermometers applied to Mt. Apo data show very good agreement with temperatures estimated using other established geothermometers, as well as bore measured temperatures. This signifies that sulphur isotopes in S-species in fluids of the Mt. Apo hydrothermal system are in equilibrium at drilled depths. In Palinpinon, on the other hand, temperature estimates from fluid and mineral sulphur isotope geothermometry calculations do not agree with, and are commonly higher than, well measured temperatures and temperatures estimated from other geothermometers. Sulphur isotopes in the presently-exploited Palinpinon fluid are not in equilibrium, and sulphur isotope geothermometry may be reflective of isotopic equilibrium of the deeper portions of the hydrothermal system. Dissolved sulphate in both the Palinpinon and Mt. Apo geothermal fluids appear to originate from the disproportionation of magmatic SO{sub 2} at temperatures below 400{degrees}C. Hydrogen sulphide in well discharge fluids are dominantly directly derived from the magma, with a minor amount coming from SO{sub 2} disproportionation.

  3. Mineral resource of the month: Strontium

    USGS Publications Warehouse

    Ober, Joyce A.

    2014-01-01

    Strontium occurs commonly in nature, ranking as the 15th most abundant chemical element on Earth. Only two minerals contain sufficient strontium, however, to be used commercially to produce strontium compounds: Strontianite (strontium carbonate) has a higher strontium content, but celestite (strontium sulfate) is by far the most abundant strontium mineral.

  4. Comparisons of multiple isotope systems in the aragonitic shells of cultured Arctica islandica clams

    NASA Astrophysics Data System (ADS)

    Liu, Y. W.; Aciego, S.; Wanamaker, A. D.

    2014-12-01

    Previous work using oxygen and stable carbon isotopes from Arctica islandica shells has shown that this archive can provide information on past seawater temperatures, carbon cycling and ocean circulation. However, relatively less attention has been devoted to other "non-traditional" isotope systems within this proxy archive. In this study, we report the boron (δ11B) and strontium isotopic values (87Sr/86Sr and δ88/86Sr) from A. islandicashells collected and cultured from the Gulf of Maine. The long-lived ocean quahog, A. islandica was collected and cultured in the Gulf of Maine for 8 months. Our high-resolution δ11B records from the experiment show 5-7‰ of increase through the culture, with low values from January to May and higher values after May. The 87Sr/86Sr ratios from both tank water and shell samples suggest that the shell material reflects ambient ocean chemistry without interferences from terrestrial sources. Although It has been suggested that stable Sr isotopic ratios (δ88/86Sr) in biogenic carbonates are influenced by the temperature of the precipitating fluid, our nearly identical δ88/86Sr data do not support this hypothesis despite a 15 °C temperature change during the experiment. Based on the in-situ measurements of culture seawater temperature, salinity and pH, and two commonly used fractionation factors (α3-4) for corals and forams, we predicted the range in shell δ11B values for the experiment. Our boron results are at the extreme ends of the two prediction lines suggesting the potential usage of the bivalve shells as seawater pH indicator. However, the wider range in δ11B in this experiment than the predictions based on other carbonate organisms (only 2 to 3‰) suggests that a species-specific fractionation factor may be required. Recent work from an additional constant temperature experiment (10 and 15 °C) in the Gulf of Maine will allow us to further evaluate temperature influences and potential vital effects on the shell boron

  5. Rb, Sr and strontium isotopic composition, K/Ar age and large ion lithophile trace element abundances in rocks and glasses from the Wanapitei Lake impact structure

    NASA Technical Reports Server (NTRS)

    Winzer, S. R.; Lum, R. K. L.; Schuhmann, S.

    1976-01-01

    Shock metamorphosed rocks and shock-produced melt glasses from the Wanapitei Lake impact structure have been examined petrographically and by electron microprobe. Eleven clasts exhibiting varying degrees of shock metamorphism and eight impact-produced glasses have been analyzed for Rb, Sr and Sr isotopic composition. Five clasts and one glass have also been analyzed for large ion lithophile (LIL) trace element abundances including Li, Rb, Sr, and Ba and the REE's. The impact event forming the Wanapitei Lake structure occurred 37 m.y. ago based on K/Ar dating of glass and glassy whole-rock samples. Rb/Sr isotopic dating failed to provide a meaningful whole-rock or internal isochron. The isotopic composition of the glasses can be explained by impact-produced mixing and melting of metasediments.

  6. Strontium and neodymium isotopic variations in early Archean gneisses affected by middle to late Archean high-grade metamorphic processes: West Greenland and Labrador

    NASA Technical Reports Server (NTRS)

    Collerson, K. D.; Mcculloch, M. T.; Bridgwater, D.; Mcgregor, V. R.; Nutman, A. P.

    1986-01-01

    Relicts of continental crust formed more than 3400 Ma ago are preserved fortuitously in most cratons. The cratons provide the most direct information about crust and mantle evolutionary processes during the first billion years of Earth history. In view of their polymetamorphic character, these terrains are commonly affected by subsequent tectonothermal events. Hence, their isotope systematics may be severely disturbed as a result of bulk chemical change or local isotopic homogenization. This leads to equivocal age and source information for different components within these terrains. The Sr and Nd isotopic data are presented for early Archean gneisses from the North Atlantic Craton in west Greenland and northern Labrador which were affected by younger metamorphic events.

  7. A strontium and neodymium isotopic study of Apollo 17 high-Ti mare basalts - Resolution of ages, evolution of magmas, and origins of source heterogeneities

    NASA Technical Reports Server (NTRS)

    Paces, James B.; Neal, Clive R.; Taylor, Lawrence A.; Nakai, Shun'ichi; Halliday, Alex N.

    1991-01-01

    The geochronological and compositional differences between previously identified magma types (A, B1, B2, and C) were investigated using high-precision Rb-Sr and Sm-Nd isotopic data for a set of Apollo 17 high-Ti mare basalt samples chosen to span the range of each of the magma types. These data, combined with previously reported geochemical ages, suggest that Apollo 17 volcanism was initially dominated by an eruption of Type B basalts. Data obtained from new whole-rock Sr and Nd isotopic analyses exhibited distinct differences in initial Sr and Nd isotopic compositions between Types A, B1, B2, and C basalts and were found to be consistent with existing petrogenetic models.

  8. Rb, Sr and strontium isotopic composition, K/Ar age and large ion lithophile trace element abundances in rocks and glasses from the Wanapitei Lake impact structure

    NASA Technical Reports Server (NTRS)

    Winzer, S. R.; Lum, R. K. L.; Schuhmann, S.

    1976-01-01

    Shock metamorphosed rocks and shock-produced melt glasses from the Wanapitei Lake impact structure have been examined petrographically and by electron microprobe. Eleven clasts exhibiting varying degrees of shock metamorphism and eight impact-produced glasses have been analyzed for Rb, Sr and Sr isotopic composition. Five clasts and one glass have also been analyzed for large ion lithophile (LIL) trace element abundances including Li, Rb, Sr, and Ba and the REE's. The impact event forming the Wanapitei Lake structure occurred 37 m.y. ago based on K/Ar dating of glass and glassy whole-rock samples. Rb/Sr isotopic dating failed to provide a meaningful whole-rock or internal isochron. The isotopic composition of the glasses can be explained by impact-produced mixing and melting of metasediments.

  9. Ion implantation system and process for ultrasensitive determination of target isotopes

    DOEpatents

    Farmer, III, Orville T.; Liezers, Martin

    2016-09-13

    A system and process are disclosed for ultrasensitive determination of target isotopes of analytical interest in a sample. Target isotopes may be implanted in an implant area on a high-purity substrate to pre-concentrate the target isotopes free of contaminants. A known quantity of a tracer isotope may also be implanted. Target isotopes and tracer isotopes may be determined in a mass spectrometer. The present invention provides ultrasensitive determination of target isotopes in the sample.

  10. Water-Rock Interactions in the Peridotite Aquifer of the Oman-UAE Ophiolite: Strontium Isotopic Ratio and Geochemical Evolution of Groundwater

    NASA Astrophysics Data System (ADS)

    Bompard, Nicolas; Matter, Juerg; Teagle, Damon

    2016-04-01

    The peridotite aquifer in Wadi Tayin, Sultanate of Oman, is a perfect example of natural carbonation of ultramafic rocks. In situ mineral carbonation is considered the most safest and permanent option of CO2 Capture and Sequestration (CCS). However, the process itself is yet to be characterised and a better understanding of the mechanisms involved in natural mineral carbonation is needed before geo-engineering it. We used the 87Sr/86Sr system to follow the water-rock interactions along the groundwater flowpath in the peridotite aquifer and to determine the sources of divalent cations (Mg2+, Ca2+) required for mineral carbonation. The Sr-isotope data of groundwater show that the aquifer rocks are the main source for divalent cations (Mg2+, Ca2+ and Sr2+) and secondary carbonates are their main sink. The groundwater 87Sr/86Sr ratio evolves with its pH: from 87Sr/86Sr = 0.7087 (n=3) to 0.7082 (n=8) between pH 7 and 8, and from 0.7086 (n=6) at pH 9 to 0.07075 (n=9) at pH 11. This evolution seems to support a two-step model for the water-rock interactions in the peridotite aquifer. From pH 7 to 8, secondary Ca-carbonate precipitation buffers the pH rise resulting from peridotite serpentinisation. From pH 9 to 11, peridotite serpentinisation drives the pH to alkaline condition. The change from a Mg-rich to a Ca-rich groundwater at pH 9 seems to confirm the two-step model.

  11. Strontium and neodymium isotope systematics of target rocks and impactites from the El'gygytgyn impact structure: Linking impactites and target rocks

    NASA Astrophysics Data System (ADS)

    Wegner, Wencke; Koeberl, Christian

    2016-12-01

    The 3.6 Ma El'gygytgyn structure, located in northeastern Russia on the Chukotka Peninsula, is an 18 km diameter complex impact structure. The bedrock is formed by mostly high-silica volcanic rocks of the 87 Ma old Okhotsk-Chukotka Volcanic Belt (OCVB). Volcanic target rocks and impact glasses collected on the surface, as well as drill core samples of bedrock and impact breccias have been investigated by thermal ionization mass spectrometry (TIMS) to obtain new insights into the relationships between these lithologies in terms of Nd and Sr isotope systematics. Major and trace element data for impact glasses are added to compare with the composition of target rocks and drill core samples. Sr isotope data are useful tracers of alteration processes and Nd isotopes reveal characteristics of the magmatic sources of the target rocks, impact breccias, and impact glasses. There are three types of target rocks mapped on the surface: mafic volcanics, dacitic tuff and lava of the Koekvun' Formation, and dacitic to rhyolitic ignimbrite of the Pykarvaam Formation. The latter represents the main contributor to the impact rocks. The drill core is divided into a suevite and a bedrock section by the Sr isotope data, for which different postimpact alteration regimes have been detected. Impact glasses from the present-day surface did not suffer postimpact hydrothermal alteration and their data indicate a coherent alteration trend in terms of Sr isotopes with the target rocks from the surface. Surprisingly, the target rocks do not show isotopic coherence with the Central Chukotka segment of the OCVB or with the Berlozhya magmatic assemblage (BMA), a late Jurassic felsic volcanic suite that crops out in the eastern part of the central Chukotka segment of the OCVB. However, concordance for these rocks exists with the Okhotsk segment of the OCVB. This finding argues for variable source magmas having contributed to the build-up of the OCVB.

  12. Lead and strontium isotopes and related trace elements as genetic tracers in the Upper Cenozoic rhyolite-basalt association of the Yellowstone Plateau volcanic field.

    USGS Publications Warehouse

    Doe, B.R.; Leeman, W.P.; Christiansen, R.L.; Hedge, C.E.

    1982-01-01

    Pb, U, Th, Rb and Sr contents and Pb- and Sr-isotopic compositions, together with field and petrological data, are consistent with the hypothesis of derivation of the basaltic and rhyolitic magmas of this volcanic field from source regions in the upper mantle and lower crust, respectively. It is suggested that the isotopic signatures of the basalts were inherited from a 2600 m.y.-old mantle 'keel' attached to the continental crust and were essentially unaffected by passage of the magma through the latter.R.J.P.

  13. Selenium Isotopes as Biosignatures in Seafloor Hydrothermal Systems

    NASA Astrophysics Data System (ADS)

    Rouxel, O.; Ludden, J.; Fouquet, Y.

    2001-12-01

    Chemically similar to sulphur, Se occurs as +6, +4, 0 and -2 valences in a variety of organic compounds and geological settings. This makes the study of Se stable isotope ratios a potential indicator of geological and biological processes. Se isotopes were first determined in the early 60's (Krouse and Thode, 1962; Rashid et al., 1978) using gas-source MS and recently by N-TIMS (Herbel et al., 2000; Johnson et al., 1999) using the double spike technique. The previous results showed that the 82Se/76Se ratio vary by as much as 15‰ and indicate that abiotic and bacterial reduction of soluble oxyanions is the dominant cause of Se isotope fractionation. Our isotopic analyses of Se were performed using a continuous flow hydride generation system coupled to a Micromass MC-ICP-MS after chemical purification. The estimated external precision of the 82Se/76Se isotope ratio is 0.25‰ (2σ ) for a quantity of Se per analysis as low as 50 ng and the data are reported relative to our internal standards (MERCK elemental standard solution). In this study we have used Se isotopes in conjunction with S isotopes to provide additional constraints on the fractionation processes in seafloor hydrothermal systems. Several fields were studied along the Mid Atlantic Ridge and include the Lucky Strike field where the setting is in a caldera system with abundant low-permeability layers of cemented breccia which result in fluid cooling and mixing below the hydrothermal vents. Based on vent structures, mineral abundance, and geochemistry, two types of hydrothermal deposits were identified: (1) high-T vents with δ 34S between 1.5 and 4.5‰ and Se values up to 2000 ppm; (2) low-T vents where pyrite and marcasite generally have lower δ 34S values (down to -1.0‰ ) and low concentration of Se (<50ppm). Se-depletion in low temperature hydrothermal deposits is interpreted as a result of subsurface precipitation of sulfides (scavenging Se from the fluid) during the conductive cooling of the

  14. Cadmium Isotope Fractionation in Soil-Wheat Systems.

    PubMed

    Wiggenhauser, Matthias; Bigalke, Moritz; Imseng, Martin; Müller, Michael; Keller, Armin; Murphy, Katy; Kreissig, Katharina; Rehkämper, Mark; Wilcke, Wolfgang; Frossard, Emmanuel

    2016-09-06

    Analyses of stable metal isotope ratios constitute a novel tool in order to improve our understanding of biogeochemical processes in soil-plant systems. In this study, we used such measurements to assess Cd uptake and transport in wheat grown on three agricultural soils under controlled conditions. Isotope ratios of Cd were determined in the bulk C and A horizons, in the Ca(NO3)2-extractable Cd soil pool, and in roots, straw, and grains. The Ca(NO3)2-extractable Cd was isotopically heavier than the Cd in the bulk A horizon (Δ(114/110)Cdextract-Ahorizon = 0.16 to 0.45‰). The wheat plants were slightly enriched in light isotopes relative to the Ca(NO3)2-extractable Cd or showed no significant difference (Δ(114/110)Cdwheat-extract = -0.21 to 0.03‰). Among the plant parts, Cd isotopes were markedly fractionated: straw was isotopically heavier than roots (Δ(114/110)Cdstraw-root = 0.21 to 0.41‰), and grains were heavier than straw (Δ(114/110)Cdgrain-straw = 0.10 to 0.51‰). We suggest that the enrichment of heavy isotopes in the wheat grains was caused by mechanisms avoiding the accumulation of Cd in grains, such as the chelation of light Cd isotopes by thiol-containing peptides in roots and straw. These results demonstrate that Cd isotopes are significantly and systematically fractionated in soil-wheat systems, and the fractionation patterns provide information on the biogeochemical processes in these systems.

  15. Utilizing Stable Isotopes and Isotopic Anomalies to Study Early Solar System Formation Processes

    NASA Technical Reports Server (NTRS)

    Simon, Justin

    2017-01-01

    Chondritic meteorites contain a diversity of particle components, i.e., chondrules and calcium-, aluminum-rich refractory inclusions (CAIs), that have survived since the formation of the Solar System. The chemical and isotopic compositions of these materials provide a record of the conditions present in the protoplanetary disk where they formed and can aid our understanding of the processes and reservoirs in which solids formed in the solar nebula, an important step leading to the accretion of planetesimals. Isotopic anomalies associated with nucleosynthetic processes are observed in these discrete materials, and can be compared to astronomical observations and astrophysical formation models of stars and more recently proplyds. The existence and size of these isotopic anomalies are typically thought to reflect a significant state of isotopic heterogeneity in the earliest Solar System, likely left over from molecular cloud heterogeneities on the grain scale, but some could also be due to late stellar injection. The homogenization of these isotopic anomalies towards planetary values can be used to track the efficiency and timescales of disk wide mixing,

  16. Unbiased isotope equilibrium factors from partial isotope exchange experiments in 3-exchange site systems

    NASA Astrophysics Data System (ADS)

    Agrinier, Pierre; Javoy, Marc

    2016-09-01

    Two methods are available in order to evaluate the equilibrium isotope fractionation factors between exchange sites or phases from partial isotope exchange experiments. The first one developed by Northrop and Clayton (1966) is designed for isotope exchanges between two exchange sites (hereafter, the N&C method), the second one from Zheng et al. (1994) is a refinement of the first one to account for a third isotope exchanging site (hereafter, the Z method). In this paper, we use a simple model of isotope kinetic exchange for a 3-exchange site system (such as hydroxysilicates where oxygen occurs as OH and non-OH groups like in muscovite, chlorite, serpentine, or water or calcite) to explore the behavior of the N&C and Z methods. We show that these two methods lead to significant biases that cannot be detected with the usual graphical tests proposed by the authors. Our model shows that biases originate because isotopes are fractionated between all these exchanging sites. Actually, we point out that the variable mobility (or exchangeability) of isotopes in and between the exchange sites only controls the amplitude of the bias, but is not essential to the production of this bias as previously suggested. Setting a priori two of the three exchange sites at isotopic equilibrium remove the bias and thus is required for future partial exchange experiments to produce accurate and unbiased extrapolated equilibrium fractionation factors. Our modeling applied to published partial oxygen isotope exchange experiments for 3-exchange site systems (the muscovite-calcite (Chacko et al., 1996), the chlorite-water (Cole and Ripley, 1998) and the serpentine-water (Saccocia et al., 2009)) shows that the extrapolated equilibrium fractionation factors (reported as 1000 ln(α)) using either the N&C or the Z methods lead to bias that may reach several δ per mil in a few cases. These problematic cases, may be because experiments were conducted at low temperature and did not reach high

  17. Strontium isotope (87Sr/86Sr) variability in the Nile Valley: identifying residential mobility during ancient Egyptian and Nubian sociopolitical changes in the New Kingdom and Napatan periods.

    PubMed

    Buzon, Michele R; Simonetti, Antonio

    2013-05-01

    As a successful technique for identifying residential mobility in other areas, this study investigates the feasibility of using 87Sr/86Sr analysis to track the movements of the ancient peoples of Egypt and Nubia in the Nile Valley, who interacted via trade, warfare, and political occupations over millennia. Dental enamel from faunal remains is used to examine variability in strontium sources in seven regional sites; human enamel samples are analyzed from eight Nile Valley sites in order to trace human movements. The faunal samples show a wide range of 87Sr/86Sr values demonstrating that some animals were raised in a variety of locales. The results of the human samples reveal overlap in 87Sr/86Sr values between Egyptian and Nubian sites; however, Egyptian 87Sr/86Sr values (mean/median [0.70777], sd [0.00027]) are statistically higher than the Nubian 87Sr/86Sr values (mean [0.70762], median [0.70757], sd [0.00036], suggesting that it is possible to identify if immigrant Egyptians were present at Nubian sites. Samples examined from the site of Tombos provide important information regarding the sociopolitical activities during the New Kingdom and Napatan periods. Based on a newly established local 87Sr/86Sr range, human values, and bioarchaeological evidence, this study confirms the preliminary idea that immigrants, likely from Egypt, were present during the Egyptian New Kingdom occupation of Nubia. In the subsequent Napatan period when Nubia ruled Egypt as the 25th Dynasty, 87Sr/86Sr values are statistically different from the New Kingdom component and indicate that only locals were present at Tombos during this developmental time.

  18. Neodymium, strontium, and oxygen isotopic variations in the crust of the western United States: Origin of Proterozoic continental crust and tectonic implications

    SciTech Connect

    Bennett, V.C.

    1989-01-01

    Initial Nd isotopic ratios of crystalline rocks from an area of about 1.5 {times} 10{sup 6} km{sup 2} of the western United States have been determined in order to map Precambrian age province boundaries and thus document the growth and modification of the North American continent in the Proterozoic. Three age provinces have been delineated. It is demonstrated that large regions of Early Proterozoic continental crust were formed with anomalous isotopic compositions ({sup 143}Nd/{sup 144}Nd ratios lower than Early Proterozoic depleted-mantle). The variations in the initial {epsilon}{sub Nd} and {delta}{sup 18}O values correlate with each other, and correspond to the previously determined Nd isotopic provinces. The Pelona, Rand, Chocolate Mountain and Orocopia Schists are represented by 15 lithologically and structurally similar schist bodies exposed along the San Andreas and Garlock faults in southern California. The grayschists have measured {epsilon}{sub Nd} values from -1.7 to -11.7 with depleted-mantle model ages of 0.9 to 1.7 Ga. The Nd isotopic compositions can be modeled as variable mixtures of Early Proterozoic continental crust with a Mesozoic are component. The measured {sup 87}Sr/{sup 86}Sr ratios are from 0.7087 to 0.7129 and reflect the presence of an old continental source. Independent of age, the high initial {epsilon}{sub Nd} values ({sup +}9 {plus minus} 1.5) are consistent with derivation at an oceanic spreading center, either at a MORB or in a back-arc basin environment. The presence of both Early Proterozoic continental detritus and a younger sedimentary component in the grayschist protolith, and the MORB affinity of the metabasalts are compatible with formation of the protoliths of the Pelona and related schists in a Mesozoic basin adjacent to the southwestern United States continental margin.

  19. Chlorine stable isotopes in sedimentary systems: does size matter?

    NASA Technical Reports Server (NTRS)

    Coleman, Max

    2004-01-01

    Stable isotope abundances vary because of size differences. The chlorine stable isotope system was one of the first described theoretically, but had a slow, disappointment strewn development, relative to other elements. Method improvement gave only small, but significant, differences in compositions of geological materials. Eventually, brines and groundwater chlorides gave larger differences. Physical processes like diffusion and adsorption, probably are the main controls of groundwater compositions. Recent work on anthropogenic groundwater contaminants shows variations resulting from manufacturing processes; implying possibilities of tracing sources.

  20. Chlorine stable isotopes in sedimentary systems: does size matter?

    NASA Technical Reports Server (NTRS)

    Coleman, Max

    2004-01-01

    Stable isotope abundances vary because of size differences. The chlorine stable isotope system was one of the first described theoretically, but had a slow, disappointment strewn development, relative to other elements. Method improvement gave only small, but significant, differences in compositions of geological materials. Eventually, brines and groundwater chlorides gave larger differences. Physical processes like diffusion and adsorption, probably are the main controls of groundwater compositions. Recent work on anthropogenic groundwater contaminants shows variations resulting from manufacturing processes; implying possibilities of tracing sources.

  1. Extreme oxygen isotope ratios in the early Solar System.

    PubMed

    Aléon, Jérôme; Robert, François; Duprat, Jean; Derenne, Sylvie

    2005-09-15

    The origins of the building blocks of the Solar System can be studied using the isotopic composition of early planetary and meteoritic material. Oxygen isotopes in planetary materials show variations at the per cent level that are not related to the mass of the isotopes; rather, they result from the mixture of components having different nucleosynthetic or chemical origins. Isotopic variations reaching orders of magnitude in minute meteoritic grains are usually attributed to stellar nucleosynthesis before the birth of the Solar System, whereby different grains were contributed by different stars. Here we report the discovery of abundant silica-rich grains embedded in meteoritic organic matter, having the most extreme 18O/16O and 17O/16O ratios observed (both approximately 10(-1)) together with a solar silicon isotopic composition. Both O and Si isotopes indicate a single nucleosynthetic process. These compositions can be accounted for by one of two processes: a single exotic evolved star seeding the young Solar System, or irradiation of the circumsolar gas by high energy particles accelerated during an active phase of the young Sun. We favour the latter interpretation, because the observed compositions are usually not expected from nucleosynthetic processes in evolved stars, whereas they are predicted by the selective trapping of irradiation products.

  2. Strontium-89 Chloride

    MedlinePlus

    ... ever had bone marrow disease, blood disorders, or kidney disease.you should know that strontium-89 chloride may interfere with the normal menstrual cycle (period) in women and may stop sperm production ...

  3. Implications of isotope data for the origin of the moon

    NASA Technical Reports Server (NTRS)

    Turcotte, D. L.; Kellogg, L. H.

    1986-01-01

    Lunar isotope data are studied in terms of lunar reservoir models. An analysis is performed to determine how the samarium-neodymium and rubidium-strontium systems evolve in terms of a two-reservoir model. Isotope data from lunar rocks show much more variability than similar data from terrestrial rocks. The midocean ridge basalts yield consistent isotope signatures on a worldwide basis suggesting that vigorous mantle convection has mixed and homogeneized the upper mantle beneath the lithosphere plates. The variability of the lunar data is taken as evidence for distinct source regions which in effect support a relatively cool origin of the moon.

  4. Implications of isotope data for the origin of the moon

    NASA Technical Reports Server (NTRS)

    Turcotte, D. L.; Kellogg, L. H.

    1986-01-01

    Lunar isotope data are studied in terms of lunar reservoir models. An analysis is performed to determine how the samarium-neodymium and rubidium-strontium systems evolve in terms of a two-reservoir model. Isotope data from lunar rocks show much more variability than similar data from terrestrial rocks. The midocean ridge basalts yield consistent isotope signatures on a worldwide basis suggesting that vigorous mantle convection has mixed and homogeneized the upper mantle beneath the lithosphere plates. The variability of the lunar data is taken as evidence for distinct source regions which in effect support a relatively cool origin of the moon.

  5. Mineral dissolution in the Cape Cod aquifer, Massachusetts, USA: I . Reaction stoichiometry and impact of accessory feldspar and glauconite on strontium isotopes, solute concentrations, and REY distribution

    USGS Publications Warehouse

    Bau, Michael; Alexander, Brian; Chesley, John T.; Dulski, Peter; Brantley, Susan L.

    2004-01-01

    To compare relative reaction rates of mineral dissolution in a mineralogically simple groundwater aquifer, we studied the controls on solute concentrations, Sr isotopes, and rare earth element and yttrium (REY) systematics in the Cape Cod aquifer. This aquifer comprises mostly carbonate-free Pleistocene sediments that are about 90% quartz with minor K-feldspar, plagioclase, glauconite, and Fe-oxides. Silica concentrations and pH in the groundwater increase systematically with increasing depth, while Sr isotopic ratios decrease. No clear relationship between 87Sr/86Sr and Sr concentration is observed. At all depths, the 87Sr/86Sr ratio of the groundwater is considerably lower than the Sr isotopic ratio of the bulk sediment or its K-feldspar component, but similar to that of a plagioclase-rich accessory separate obtained from the sediment. The Si-87Sr/86Sr-depth relationships are consistent with dissolution of accessory plagioclase. In addition, solutes such as Sr, Ca, and particularly K show concentration spikes superimposed on their respective general trends. The K-Sr-87Sr/86Sr systematics suggests that accessory glauconite is another major solute source to Cape Cod groundwater. Although the authigenic glauconite in the Cape Cod sediment is rich in Rb, it is low in in-grown radiogenic 87Sr because of its young Pleistocene age. The low 87Sr/86Sr ratios are consistent with equilibration of glauconite with seawater. The impact of glauconite is inferred to vary due to its variable abundance in the sediments. In the Cape Cod groundwater, the variation of REY concentrations with sampling depth resembles that of K and Rb, but differs from that of Ca and Sr. Shale-normalized REY patterns are light REY depleted, show negative Ce anomalies and super-chondritic Y/Ho ratios, but no Eu anomalies. REY input from feldspar, therefore, is insignificant compared to input from a K-Rb-bearing phase, inferred to be glauconite. These results emphasize that interpretation of groundwater

  6. Mineral dissolution in the Cape Cod aquifer, Massachusetts, USA: I . Reaction stoichiometry and impact of accessory feldspar and glauconite on strontium isotopes, solute concentrations, and REY distribution

    NASA Astrophysics Data System (ADS)

    Bau, Michael; Alexander, Brian; Chesley, John T.; Dulski, Peter; Brantley, Susan L.

    2004-03-01

    To compare relative reaction rates of mineral dissolution in a mineralogically simple groundwater aquifer, we studied the controls on solute concentrations, Sr isotopes, and rare earth element and yttrium (REY) systematics in the Cape Cod aquifer. This aquifer comprises mostly carbonate-free Pleistocene sediments that are about 90% quartz with minor K-feldspar, plagioclase, glauconite, and Fe-oxides. Silica concentrations and pH in the groundwater increase systematically with increasing depth, while Sr isotopic ratios decrease. No clear relationship between 87Sr/ 86Sr and Sr concentration is observed. At all depths, the 87Sr/ 86Sr ratio of the groundwater is considerably lower than the Sr isotopic ratio of the bulk sediment or its K-feldspar component, but similar to that of a plagioclase-rich accessory separate obtained from the sediment. The Si- 87Sr/ 86Sr-depth relationships are consistent with dissolution of accessory plagioclase. In addition, solutes such as Sr, Ca, and particularly K show concentration spikes superimposed on their respective general trends. The K-Sr- 87Sr/ 86Sr systematics suggests that accessory glauconite is another major solute source to Cape Cod groundwater. Although the authigenic glauconite in the Cape Cod sediment is rich in Rb, it is low in in-grown radiogenic 87Sr because of its young Pleistocene age. The low 87Sr/ 86Sr ratios are consistent with equilibration of glauconite with seawater. The impact of glauconite is inferred to vary due to its variable abundance in the sediments. In the Cape Cod groundwater, the variation of REY concentrations with sampling depth resembles that of K and Rb, but differs from that of Ca and Sr. Shale-normalized REY patterns are light REY depleted, show negative Ce anomalies and super-chondritic Y/Ho ratios, but no Eu anomalies. REY input from feldspar, therefore, is insignificant compared to input from a K-Rb-bearing phase, inferred to be glauconite. These results emphasize that interpretation of

  7. Boron and strontium isotope ratios and major/trace elements concentrations in tea leaves at four major tea growing gardens in Taiwan.

    PubMed

    Chang, Cheng-Ta; You, Chen-Feng; Aggarwal, Suresh Kumar; Chung, Chuan-Hsiung; Chao, Hung-Chun; Liu, Hou-Chun

    2016-06-01

    Isotopic compositions of B and Sr in rocks and sediments can be used as tracers for plant provincial sources. This study aims to test whether tea leaf origin can be discriminated using (10)B/(11)B and Sr isotopic composition data, along with concentrations of major/trace elements, in tea specimens collected from major plantation gardens in Taiwan. The tea leaves were digested by microwave and analyzed by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The data showed significant variations in (87)Sr/(86)Sr ratios (from 0.70482 to 0.71462), which reflect changes in soil, groundwater or irrigation conditions. The most radiogenic tea leaves were found at the Taitung garden and the least radiogenic ones were from the Hualien garden. The δ (11)B was found to change appreciably (δ (11)B = 0.38-23.73 ‰) which could be due to fertilizers. The maximum δ (11)B was also observed in tea samples from the Hualien garden. Principal component analysis combining (87)Sr/(86)Sr, δ (11)B and major/trace elements results successfully discriminated different sources of major tea gardens in Taiwan, except the Hualien gardens, and this may be due to rather complicated local geological settings.

  8. CONTROL SYSTEM FOR ISOTOPE SEPARATING APPARATUS

    DOEpatents

    Barnes, S.W.

    1960-01-26

    A method is described for controlling the position of the ion beams in a calutron used for isotope separation. The U/sup 238/ beams is centered over the U/sup 235/ receiving pocket, the operator monitoring the beam until a maximum reading is achieved on the meter connected to that pocket. Then both beams are simultaneously shifted by a preselected amount to move the U/sup 235/ beam over the U/sup 235/ pocket. A slotted door is placed over the entrance to that pocket during the U/sup 238/ beam centering to reduce the contamination to the pocket, while allowing enough beam to pass for monitoring purposes.

  9. Nitrogen isotopic components in the early solar system

    NASA Technical Reports Server (NTRS)

    Kerridge, J. F.

    1994-01-01

    It is quite common to take the terrestrial atmospheric value of (15)N/(14)N (0.00366) as typical of nitrogen in the early solar system, but in fact there is little reason to suppose that this value had a nebula-wide significance. Indeed, it is not clear that there was a unique solar-system-wide (15)N/(14)N ratio, of whatever value. Here we review what is known about the distribution of the nitrogen isotopes among those solar-system objects that have been sampled so far and conclude that those isotopes reveal widespread inhomogeneity in the early solar system. Whether the isotopically distinct primordial components implied by this analysis were solid or gaseous or a mixture of both is not known. The isotopic composition of N in the Earth's mantle is controversial: estimates range from a 1.1 percent depletion in (15)N to a 1.4 percent enrichment. (Isotopic compositions will be expressed throughout as percent deviations from the terrestrial atmospheric value.) The present-day Martian atmosphere is characterized by a value of plus 62 percent but this enrichment in (15)N is attributed to selective loss of (14)N from the Martian exosphere. Modelling of this fractionation leads to an estimated primordial composition similar to the terrestrial atmospheric value, through the precision of this model-dependent result is unclear.

  10. Unique Features and Spacecraft Applications of Dynamic Isotope Power Systems

    SciTech Connect

    Raab, B.

    1982-01-01

    The dynamic isotope power system represents the most recent attempt to develop a heat-engine generator for space electric power. A major objective in this most recent effort was to increase the power and to reduce the cost of nuclear space power systems to the point where the unique features of this power source could be brought to bear for Earth-orbit missions which could benefit therefrom. This objective was largely achieved; both weight and cost of the dynamic isotope systems are comparable to solar power systems. The dynamic isotope power system, designed for spacecraft requiring prime power in the 500-2000 W range, has been successfully built and ground tested. A number of studies, summarized herein, have demonstrated the advantages of using such a power system instead of the conventional solar system for a variety of Earth-orbit missions. These advantages stem from the unique nature of the dynamic isotope system, different in kind from solar power systems. As a result, in many cases, the spacecraft design can be significantly simplified and more closely harmonized with mission requirements. This overall advantage can be crucial in missions which have stringent pointing, stability, viewing, and/or positioning requirements.

  11. Recovery of strontium activity from a strontium-82/rubidium-82 generator

    DOEpatents

    Taylor, Wayne A.; Phillips, Dennis R.; Sosnowski, Kenneth M.

    1999-10-12

    Strontium-82 is recovered from spent strontium-82/rubidium-82 generators to provide a source of strontium-82 for additional strontium-82/rubidium-82 generators. The process involves stripping of the strontium-82 from used strontium-82/rubidium-82 generators followed by purification of the strontium-82 material to remove additional metal contaminants to desired levels.

  12. Uranium and Strontium Isotopic Study of the Hydrology of the Alluvial Aquifer at the Rifle Former U Mine Tailings Site, Colorado

    NASA Astrophysics Data System (ADS)

    Christensen, J. N.; Shiel, A. E.; Conrad, M. E.; Williams, K. H.; Dong, W.; Tokunaga, T. K.; Wan, J.; Long, P. E.; Hubbard, S. S.

    2014-12-01

    The Rifle Site consists of a floodplain along the Colorado River that was remediated through the removal of surface material underlying former uranium-vanadium mill tailings. The semi-arid (precip. = ~30 cm/year) catchment for the site has an area of ~1km2. The Rifle Site provides an excellent field laboratory for the study of the fluxes of water and carbon from the vadose zone to groundwater (LBNL SFA2.0, http://esd.lbl.gov/research/projects/sssfa2/). A network of monitoring wells, particularly a set instrumented in the vadose zone, provide the opportunity to closely sample groundwater and vadose zone porewater both in space and time. In order to better understand the spatial and temporal variation of vadose zone interaction with groundwater within the Rifle floodplain and provide constraints for a Rifle hydrological model, we have analyzed the Sr isotopic compositions, 234U/238U activity ratios, and d238U of groundwater, vadose zone porewater (sampled through depth-distributed lysimeters) and surface water including the Colorado River. Significant contrasts in 87Sr/86Sr and 234U/238U allow the identification of different sources contributing to Rifle groundwater, while d238U provides an additional tracer and insights into redox processes. Vadose zone porewater is characterized by high 87Sr/86Sr and Sr concentrations and falls at one end of a mixing line with Rifle groundwater, while upgradient groundwater with lower 87Sr/86Sr and Sr concentrations falls at the other end. A mixing model using vadose zone porewater and upgradient groundwater as endmembers suggests that the contribution of vertical recharge through the floodplain increases to ~20% systematically across the floodplain towards the Colorado River. An exception to this pattern is a well located 150m from the river with recent high U concentrations (>300 ppb) and U and Sr isotopic compositions consistent with a 38% vadose zone contribution. U and Sr isotopes show that an irrigation-return ditch that cuts

  13. The genesis of the amethyst geodes at Artigas (Uruguay) and the paleohydrology of the Guaraní aquifer: structural, geochemical, oxygen, carbon, strontium isotope and fluid inclusion study

    NASA Astrophysics Data System (ADS)

    Morteani, Giulio; Kostitsyn, Y.; Preinfalk, C.; Gilg, H. A.

    2010-06-01

    The amethyst-bearing geodes found in the flood basalts of the Arapey formation at Artigas (Uruguay) were formed as protogeodes by bubbles of CO2-rich basalt-derived fluids. The formation of the celadonite rim and the lining of the geodes by agate followed by quartz and amethyst were driven by the artesian water of the Guaraní aquifer percolating the basalts from below. The temperature of the amethyst formation is estimated from fluid inclusion data to be between 50° and 120°C. Oxygen stable isotope data suggest a crystallization temperature of calcite of about only 24°C. The actual wellhead temperature of the water produced from the Guaraní aquifer in the study area is around 29°C.

  14. Rubidium-87/strontium-87 age of juvinas basaltic achondrite and early igneous activity in the solar system.

    PubMed

    Allégre, C J; Birck, J L; Fourcade, S; Semet, M P

    1975-02-07

    A (4.60+/-0.07)x10(9) year internal isochron has been drawn for the achondrite Juvinas by the rubidium-87/strontium-87 method. Earlier petrographic investigation of achondrites supplemented by a new ion microprobe study of Juvinas strongly suggest an igneous origin for this class of meteorites. The results thus indicate that igneous activity may have rapidly followed the formation of the achondrites' parent body 4.6x10(9) years ago.

  15. Mo isotope fractionation during hydrothermal evolution of porphyry Cu systems

    NASA Astrophysics Data System (ADS)

    Shafiei, Behnam; Shamanian, GholamHossein; Mathur, Ryan; Mirnejad, Hassan

    2015-03-01

    We present Mo isotope compositions of molybdenite types from three successive stages of ore deposition in several porphyry copper deposits of the Kerman region, Iran. The data provide new insights into controlling processes on Mo isotope fractionation during the hydrothermal evolution of porphyry systems. The Mo isotope compositions of 27 molybdenite samples show wide variations in δ97Mo ranging from -0.37 to +0.92 ‰. The data reveal that molybdenites in the early and transitional stages of mineralization (preferentially 2H polytypes; δ97Mo mean = 0.35 ‰) have higher δ97Mo values than late stage (mainly 3R polytypes; δ97Mo mean = 0.02 ‰) molybdenites. This trend suggests that fractionation of Mo isotopes occurred in high-temperature stages of mineralization and that hydrothermal systems generally evolve towards precipitation of molybdenite with lower δ97Mo values. Taking into account the genetic models proposed for porphyry Cu deposits along with the temperature-dependent fractionation of Mo isotope ratios, it is proposed that large variations of Mo isotopes in the early and the transitional stages of ore deposition could be controlled by the separation of the immiscible ore-forming fluid phases with different density, pH, and ƒO2 properties (i.e., brine and vapor). The fractionation of Mo isotopes during fluid boiling and Rayleigh distillation processes likely dominates the Mo isotope budget of the remaining ore-forming fluids for the late stage of mineralization. The lower δ97Mo values in the late stage of mineralization can be explained by depletion of the late ore-forming hydrothermal solutions in 97Mo, as these fluids have moved to considerable distance from the source. Finally, the relationship observed between MoS2 polytypes (2H and 3R) and their Mo isotopic compositions can be explained by the molecular vibration theory, in which heavier isotopes are preferentially partitioned into denser primary 2H MoS2 crystals.

  16. Strontium-loaded mineral bone cements as sustained release systems: Compositions, release properties, and effects on human osteoprogenitor cells.

    PubMed

    Tadier, Solène; Bareille, Reine; Siadous, Robin; Marsan, Olivier; Charvillat, Cédric; Cazalbou, Sophie; Amédée, Joelle; Rey, Christian; Combes, Christèle

    2012-02-01

    This study aims to evaluate in vitro the release properties and biological behavior of original compositions of strontium (Sr)-loaded bone mineral cements. Strontium was introduced into vaterite CaCO3 -dicalcium phosphate dihydrate cement via two routes: as SrCO3 in the solid phase (SrS cements), and as SrCl2 dissolved in the liquid phase (SrL cements), leading to different cement compositions after setting. Complementary analytical techniques implemented to thoroughly investigate the release/dissolution mechanism of Sr-loaded cements at pH 7.4 and 37°C during 3 weeks revealed a sustained release of Sr and a centripetal dissolution of the more soluble phase (vaterite) limited by a diffusion process. In all cases, the initial burst of the Ca and Sr release (highest for the SrL cements) that occurred over 48 h did not have a significant effect on the expression of bone markers (alkaline phosphatase, osteocalcin), the levels of which remained overexpressed after 15 days of culture with human osteoprogenitor (HOP) cells. At the same time, proliferation of HOP cells was significantly higher on SrS cements. Interestingly, this study shows that we can optimize the sustained release of Sr(2+) , the cement biodegradation and biological activity by controlling the route of introduction of strontium in the cement paste.

  17. AVLIS enrichment of medical isotopes

    SciTech Connect

    Haynam, C.A.; Scheibner, K.F.; Stern, R.C.; Worden, E.F.

    1996-12-31

    Under the Sponsorship of the United states Enrichment Corporation (USEC), we are currently investigating the large scale separation of several isotopes of medical interest using atomic vapor isotope separation (AVLIS). This work includes analysis and experiments in the enrichment of thallium 203 as a precursor to the production of thallium 201 used in cardiac imaging following heart attacks, on the stripping of strontium 84 from natural strontium as precursor to the production of strontium 89, and on the stripping of lead 210 from lead used in integrated circuits to reduce the number of alpha particle induced logic errors.

  18. Precision frequency measurement of visible intercombination lines of strontium.

    PubMed

    Ferrari, G; Cancio, P; Drullinger, R; Giusfredi, G; Poli, N; Prevedelli, M; Toninelli, C; Tino, G M

    2003-12-12

    We report the direct frequency measurement of the visible 5s(2) 1S0-5s5p 3P1 intercombination line of strontium that is considered a possible candidate for a future optical-frequency standard. The frequency of a cavity-stabilized laser is locked to the saturated fluorescence in a thermal Sr atomic beam and is measured with an optical-frequency comb generator referenced to the SI second through a global positioning system signal. The 88Sr transition is measured to be at 434 829 121 311 (10) kHz. We measure also the 88Sr-86Sr isotope shift to be 163 817.4 (0.2) kHz.

  19. Observation system simulation experiments using water vapor isotope information

    NASA Astrophysics Data System (ADS)

    Yoshimura, Kei; Miyoshi, Takemasa; Kanamitsu, Masao

    2014-07-01

    Measurements of water vapor isotopes (δ18O and δD) have dramatically increased in recent years with the availability of new spectroscopic technology. To utilize these data more efficiently, this study first developed a new data assimilation system using a local transform ensemble Kalman filter (LETKF) and the Isotope-incorporated Global Spectral Model (IsoGSM). An observation system simulation experiment (OSSE) was then conducted. The OSSE used a synthetic data set of vapor isotope measurements, mimicking Tropospheric Emission Spectrometer (TES)-retrieved δD from the mid-troposphere, SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY)-retrieved δD from the water vapor column, and the virtual Global Network of Isotopes in Precipitation (GNIP)-like surface vapor isotope (both δD and δ18O) monitoring network. For TES and SCIAMACHY, we assumed a similar spatiotemporal coverage as that of the real data sets. For the virtual GNIP-like network, we assumed ~200 sites worldwide and 6-hourly measurements. An OSSE with 20 ensemble members was then conducted for January 2006. The results showed a significant improvement in not only the vapor isotopic field but also meteorological fields, such as wind speed, temperature, surface pressure, and humidity, when compared with a test with no observations. For surface air temperature, the global root mean square error has dropped by 10%, with 40-60% of the decrease occurring in the east-southeast Asia where the concentration of observations is relatively higher. When there is a conventional radiosonde network, the improvement gained by adding isotopic measurements was small but positive for all variables.

  20. Modeling of strontium sorption and speciation in a natural sediment-groundwater system

    NASA Astrophysics Data System (ADS)

    Koss, V.; Kim, J. I.

    1990-10-01

    The sorption of Sr in 21 natural sediment-groundwater systems from Gorleben, F.R.G., has been modeled using a simple surface complexation model. An apparent constant of Sr sorption has been computed taking into account bulk cation-exchange capacity of the sediment, the analytical composition of groundwater and experimental sorption data obtained from related systems. The method of determining the prevailing surface complex has been described in detail, using changing properties of the natural systems. Apparent sorption constants of natural groundwater components — Ca 2+, Mg 2+, K + and Na + — have been estimated. Competition from natural groundwater components for sorption sites has been taken into account. The main parameters governing Sr 2+ sorption are cation-exchange capacity of the sediment and ionic strength of the groundwater. The model describes the influence of experimental volume to mass ratio and of Sr 2+ concentration on sorption and allows one to compare the varying sorption data of similar systems. Computations were performed using the geochemical code MINEQL.

  1. Carbon isotope effects in carbonate systems

    NASA Astrophysics Data System (ADS)

    Deines, Peter

    2004-06-01

    Global carbon cycle models require a complete understanding of the δ 13C variability of the Earth's C reservoirs as well as the C isotope effects in the transfer of the element among them. An assessment of δ 13C changes during CO 2 loss from degassing magmas requires knowledge of the melt-CO 2 carbon isotope fractionation. In order to examine the potential size of this effect for silicate melts of varying composition, 13C reduced partition functions were computed in the temperature range 275 to 4000 K for carbonates of varying bond strengths (Mg, Fe, Mn, Sr, Ba, Pb, Zn, Cd, Li, and Na) and the polymorphs of calcite. For a given cation and a given pressure the 13C content increases with the density of the carbonate structure. For a given structure the tendency to concentrate 13C increases with pressure. The effect of pressure (‰/10 kbar) on the size of the reduced partition function of aragonite varies with temperature; in the pressure range 1 to 10 5 bars the change is given by: Δ 13C p average=-0.01796+0.06635∗ 10 3/T+0.006875∗ 10 6/T2 For calcite III the pressure effect is on average 1.4× larger than that for aragonite at all temperatures. The nature of the cation in a given structure type has a significant effect on the carbon isotope fractionation properties. The tendency to concentrate 13C declines in the series magnesite, aragonite, dolomite, strontianite, siderite, calcite, smithonite, witherite, rhodochrosite, otavite, cerrusite. For divalent cations a general expression for an estimation of the reduced partition function (β) from the reduced mass (μ = [M Cation × M Carbonate]/[M Cation + M Carbonate]) is: 1000 lnβ=(0.032367-0.072563∗ 10 3/T-0.01073∗ 10 6/T2)∗μ-14.003+29.953∗ 10 3/T+9.4610∗ 10 6/T2 For Mg-calcite the 13C content varies with the Mg concentration. The fractionation between Mg-calcite (X = mole fraction of MgCO 3) and calcite is given by: 1000 ln(α MgCalite- Calcite)=[0.013702-0.10957× 10 3/T+1.35940× 10 6/T2

  2. Phase Pattern of Barium Strontium Titanate System and Dielectric Responses of Its Solid Solutions

    NASA Astrophysics Data System (ADS)

    Sadykov, Kh. A.; Verbenko, I. A.; Reznichenko, L. A.; Pavelko, A. A.; Shilkina, L. A.; Konstantinov, G. M.; Abubakarov, A. G.; Shevtsova, S. I.; Pavlenko, A. V.; Khasbulatov, S. V.

    2017-04-01

    Samples of solid solutions of the system Ba1- x Sr x TiO3 (0 ≤ x ≤1.0) are produced by solid-phase synthesis followed by sintering using conventional ceramic technology. Their crystal structure and grain structure are studied at room temperature and dielectric properties - in a wide range of external influences (temperature and frequency of the alternating electric field). Based on these results, the state diagram of the system is constructed including three single-phase fields with different-symmetry (tetragonal, pseudocubic, and cubic) and two morphotropic fields with coexistence of the tetragonal and pseudocubic, pseudocubic and cubic phases. Peculiarities of the grain landscape associated with the formation of morphotropic areas and melting of barium hydroxide are revealed. The dependence of the dielectric properties of solid solutions on their crystal-chemical specifics and position in the phase diagram of the system is demonstrated. A conclusion is made about the possibility of using the compositions with x = 0.2 to create materials with high dielectric constants promising for applications in microelectronics.

  3. A new dimension to the Sr isotope system - (88/86)Sr record of marine carbonates in the Phanerozoic

    NASA Astrophysics Data System (ADS)

    Vollstaedt, H.; Eisenhauer, A.; Krabbenhoeft, A.; Farkas, J.; Veizer, J.

    2009-12-01

    For the first time we extend and complete the application of the radiogenic Sr isotope system (87Sr/86Sr) with a simultaneous measurement of radiogenic and stable strontium (Sr) isotopes (δ(88/86)Sr[‰]=(88Sr/86Srsample/88Sr/86Sr(NBS987)-1)*1000). Taking Sr isotope fractionation into account this opens a new dimension for the Sr isotope system allowing to gain quantitative information about the Sr output from the ocean. Applying a 87Sr/84Sr-double spike we measured paired δ(88/86)Sr-87Sr/86Sr* ratios of Phanerozoic marine carbonates samples which were screened for diagenesis prior to the measurement. The 87Sr/86Sr* ratios are renormalized to δ(88/86)Sr=0‰ (88Sr/86Sr=8.375209) in order to be compatible to the radiogenic Sr isotope system values. Data reduction and denormalization follows an iterative algorithm by Krabbenhöft et al. (2009). External δ(88/86)Sr reproducibility based on an internal coral carbonate standard (JCp-1) corresponds to 0.008‰ (2SEM). Our data reveal that the δ(88/86)Sr values of Phanerozoic brachiopods and belemnites samples are in the range of modern marine carbonates (JCp-1 coral standard value: 0.192±0.008‰) but isotopically lighter than modern seawater (δ(88/86)Sr(IAPSO)= 0.385±0.007‰) being in the range between ~0.080‰ and ~0.370‰ (mean of 0.168). We observe a decrease in δ(88/86)Sr from Ordovician (0.200‰) to Silurian period (0.080‰) with a consequent increase in δ(88/86)Sr towards the upper Permian period. Highest values (~0.370‰) of δ(88/86)Sr are reached close to the Permian/Triassic boundary. This study examines the main factors that control δ(88/86)Sr on Phanerozoic timescale. It was found that temperature is not the main factor that drives δ(88/86)Sr of marine carbonates. Rather we suggest that the δ(88/86)Sr of Phanerozoic seawater is controlled by changes in the Sr fluxes in and out of the ocean. Modeling of our data allows a quantification of the Phanerozoic imbalance between the Sr input and

  4. Strontium isotopic ages of the Torinosu-type limestones (latest Jurassic to earliest Cretaceous, Japan): Implication for biocalcification event in northwestern Palaeo-Pacific

    NASA Astrophysics Data System (ADS)

    Kakizaki, Yoshihiro; Ishikawa, Tsuyoshi; Nagaishi, Kazuya; Tanimizu, Masaharu; Hasegawa, Takashi; Kano, Akihiro

    2012-03-01

    The ages of the Late Jurassic to the Early Cretaceous shallow marine limestones in Japan (the Torinosu-type limestones) were evaluated by Sr isotopic stratigraphy. The 87Sr/86Sr ratios of 17 brachiopods collected from three sections revealed ages that are consistent with the previous assumption based on biostratigraphy. The age of the upper horizon of the Koike Limestone Member (the Soma-Nakamura Group, NE Japan) ranges from 150.6 Ma to 149.2 Ma (the latest Kimmeridgian to the early Tithonian). The limestones from two sections (the Torinosu and Imaidani Group) on Shikoku Island of SW Japan yield the younger ages, which evaluate the depositional rate of the two limestones 6.3-14.5 m/m.y. By applying these rates, the depositional period was estimated for the whole limestone of each section; from 151.1 Ma (the latest Kimmeridgian) to 140.3 Ma (the latest Berriasian) for the Torinosu Group, from 151.5 Ma (the late Kimmeridgian) to 143.0 Ma (the early Berriasian) for the Imaidani Group. These results confirm active carbonate deposition in the shallow fore-arc platform in SW Japan from the Tithonian to the Berriasian. The biocalcification event recognized in relevant age in the Tethyan region was likely expanded to the Palaeo-Pacific. The carbonate deposition in the platform was terminated by sea level fall during the early Valanginian.

  5. Photostriction of strontium ruthenate

    PubMed Central

    Wei, Tzu-Chiao; Wang, Hsin-Ping; Liu, Heng-Jui; Tsai, Dung-Sheng; Ke, Jr-Jian; Wu, Chung-Lun; Yin, Yu-Peng; Zhan, Qian; Lin, Gong-Ru; Chu, Ying-Hao; He, Jr-Hau

    2017-01-01

    Transition metal oxides with a perovskite crystal structure exhibit a variety of physical properties associated with the lattice. Among these materials, strontium ruthenate (SrRuO3) displays unusually strong coupling of charge, spin and lattice degrees of freedom that can give rise to the photostriction, that is, changes in the dimensions of material due to the absorption of light. In this study, we observe a photon-induced strain as high as 1.12% in single domain SrRuO3, which we attribute to a nonequilibrium of phonons that are a result of the strong interaction between the crystalline lattice and electrons excited by light. In addition, these light-induced changes in the SrRuO3 lattice affect its electrical resistance. The observation of both photostriction and photoresistance in SrRuO3 suggests the possibility of utilizing the mechanical and optical functionalities of the material for next-generation optoelectronics, such as remote switches, light-controlled elastic micromotors, microactuators and other optomechanical systems. PMID:28436430

  6. System for recovery of daughter isotopes from a source material

    SciTech Connect

    Tranter, Troy J; Todd, Terry A; Lewis, Leroy C; Henscheid, Joseph P

    2009-08-04

    A method of separating isotopes from a mixture containing at least two isotopes in a solution is disclosed. A first isotope is precipitated and is collected from the solution. A daughter isotope is generated and collected from the first isotope. The invention includes a method of producing an actinium-225/bismuth-213 product from a material containing thorium-229 and thorium-232. A solution is formed containing nitric acid and the material containing thorium-229 and thorium-232, and iodate is added to form a thorium iodate precipitate. A supernatant is separated from the thorium iodate precipitate and a second volume of nitric acid is added to the thorium iodate precipitate. The thorium iodate precipitate is stored and a decay product comprising actinium-225 and bismuth-213 is generated in the second volume of nitric acid, which is then separated from the thorium iodate precipitate, filtered, and treated using at least one chromatographic procedure. A system for producing an actinium-225/bismuth-213 product is also disclosed.

  7. ``Recycling'' Geophysics: Monitoring and Isotopic Analysis of Engineered Biological Systems

    NASA Astrophysics Data System (ADS)

    Doherty, R.; Singh, K. P.; Ogle, N.; Ntarlagiannis, D.

    2010-12-01

    The emerging sub discipline of biogeophysics has provoked debate on the mechanisms of microbial processes that may contribute to geophysical signatures. At field scales geophysical signatures are often non unique due to the many parameters (physical, chemical, and biological) that are involved. It may be easier to apply geophysical techniques such as electrodic potential (EP), self potential (SP) and induced polarization (IP) to engineered biological systems where there is a degree of control over the design of the physical and chemical domain. Here we present results of a column experiment that was designed to anaerobically biodegrade dissolved organic matter in landfill leachate. The column utilises a recycled porous media (concrete) to help sequester organic carbon. Electrodic potential, self potential and induced polarisation are used in conjunction with chemical and isotopic techniques to monitor the effectiveness of this approach. Preliminary carbon and oxygen isotopic analysis on concrete from the column in contact with leachate show isotopic enrichment suggesting abiotic precipitation of carbonates.

  8. Calcium versus strontium handling by the heart muscle.

    PubMed

    Hendrych, Michal; Olejnickova, Veronika; Novakova, Marie

    2016-01-01

    Calcium plays a crucial role in numerous processes in living systems, from both intracellular and intercellular signalling to blood clotting. Calcium can be replaced by strontium in various intracellular processes due to high level of their similarity and strontium thus may serve as a valuable tool for different experimental studies. On the other hand, strontium is also used in clinical medicine and is commonly taken to the human body with food and water. The negative cardiac side effects of strontium therapy of osteoporosis and bone metastases are well known, but still not fully explained. This fact explains enhanced interest in this element and its impact on human body. This article reviews effects of calcium and strontium on several biochemical and physiological processes, with special emphasis on cardiac muscle.

  9. Multiple sources for ore-forming fluids in the Neves Corvo VHMS Deposit of the Iberian Pyrite Belt (Portugal): strontium, neodymium and lead isotope evidence

    NASA Astrophysics Data System (ADS)

    Relvas, Jorge M.; Tassinari, Colombo C.; Munhá, José; Barriga, Fernando J.

    2001-08-01

    Lead, Rb-Sr, and Sm-Nd isotopes have been used to constrain the sources and the timing of mineralisation at the Neves Corvo VHMS deposit of the Iberian Pyrite Belt (IPB). Sulfide- and cassiterite-rich ores, together with a mineralised felsic volcanic rock, yield a Rb-Sr errorchron age of 347±25 Ma with an initial 87Sr/86Sr=0.71031±65. The Rb-Sr results agree with palynological age constraints for ore formation at Neves Corvo, and are indistinguishable from several other mineralisation ages, indicating that major orebodies in the IPB formed coevally at ~350 Ma. In contrast, wide variations in initial 143Nd/144Nd indicate limited rare-earth-element redistribution during ore deposition. Initial ɛNd (350 Ma) values range from -0.2 to -9.7 for copper ores, -8.9 to -9.4 for copper-tin ores, and -6.9 (cassiterite) to -9.5 for tin ores, implying that neither the IPB volcanic host rocks [ɛNd (350 Ma) >-2.1; 87Sr/86Sr0<0.70664], nor contemporaneous seawater (87Sr/86Sr0 ~0.708), could have been the exclusive sources for the Neves Corvo ores. Distinct mixing arrays in the ɛNd (350 Ma)-Sm/Nd and 206Pb/204Pb-207Pb/204Pb diagrams demonstrate that sulfide and tin ore deposition involved ore-forming solutions from different sources. Whereas sulfide-ore compositional variations are consistent with significant incorporation of "typical" IBP volcanic-seawater derived hydrothermal components, the highly radiogenic lead and (exclusively) low-ɛNd values preserved in tin ores require a predominant derivation from external sources. This could be either a magmatic source (which must have been different from the typical IPB felsic magmas), or a metamorphic fluid deeply circulated through older basement rocks.

  10. Film growth and structure design in the barium oxide-strontium oxide-titanium dioxide system

    NASA Astrophysics Data System (ADS)

    Fisher, Patrick J.

    This thesis describes the growth and characterization of thin films in the SrO-BaO-TiO2 system. The films are grown by molecular beam cpitaxy (MBE) and pulsed laser deposition (PLD) on ceramic substrates, and characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), reflection-high energy electron diffraction (RHEED), and transmission electron microscopy (TEM). Films are grown with varied global and initial local stoichiometries, with the goal of determining the stability of specific cation organizations. Simple oxides, TiO2 (anatase) and SrO (rock salt) were grown on oxide substrates using MBE. Growth conditions, including substrate material, substrate temperature, O3 flux, and metal flux, are varied in each case. It is observed that the growth morphology of anatase is highly dependent on the ozone flux, with fluxes of 1.00 sccm and greater resulting in flat anatase surfaces. Increased roughness at higher substrate was determined to be a result of rutile inclusions. Growth oscillations are observed in the RHEED intensity for both TiO2 and SrO in overlapping regions of growth space, indicating 2D growth modes. Varied shuttering sequences were used during MBE growth of perovskites: globally non-stoichiometric films, as well as locally non-stoichiometric but globally stoichiometric perovskite. Films were grown within a (SrO) m(TiO2)n framework, where growth cycles involved m monolayers of SrO followed by n monolayers of TiO2. XRD results indicate that Ruddlesden-Popper defects, that is, rock salt double layers, enable incorporation of all levels of Sr excess, whereas excess Ti is observed to incorporate into the perovskite structure only at extreme excesses. A series of films with m equal to n were grown; that is, multiple monolayers of SrO deposited followed by multiple monolayers of TiO2. These initially locally non-stoichiometric arrangements interreact to form highly crystalline perovskite, even with layer thicknesses of up to 33 monolayers. The

  11. Geochemical and isotopic (oxygen, hydrogen, carbon, strontium) constraints for the origin, salinity, and residence time of groundwater from a carbonate aquifer in the Western Anti-Atlas Mountains, Morocco

    NASA Astrophysics Data System (ADS)

    Ettayfi, N.; Bouchaou, L.; Michelot, J. L.; Tagma, T.; Warner, N.; Boutaleb, S.; Massault, M.; Lgourna, Z.; Vengosh, A.

    2012-05-01

    SummaryGroundwater in many arid basins, particularly in developing countries, is the only available water resource that sustains local communities. Yet, information on the basic hydrological parameters and the sustainability of the groundwater exploitation are often lacking. This study investigates the origin of groundwater from the Lower Cambrian carbonate aquifer of the Lakhssas Plateau in the Anti-Atlas Mountains of southwestern Morocco. The study aims to reveal the origin of the groundwater, salinity sources, and the residence time of the water. The study is based on a comprehensive geochemical and isotopic (oxygen, hydrogen, carbon, and strontium) investigation of groundwater from different parts of the basin. The hydrochemical and isotopes results indicated three types of groundwater in the Lakhssas Plateau: (1) thermal water in the southern part of the basin with solute composition that reflects dissolution of calcium-sulfate and calcium carbonate minerals; (2) low-temperature groundwater at the southern margin of the basin with low salinity (chloride content up to 100 mg/L) and chemical composition that is expected from equilibrium with limestone-dolomite rocks; and (3) low-temperature groundwater in the northern, western, and eastern margins of the basin with a wide range of salinity (chloride up to 800 mg/L). The different water types had also different stable isotope composition; the thermal water was depleted in 18O and 2H (δ18O as low as -7.6‰) relative to the southern (-5.9 to -5.3‰) and northern waters (-5.7 to -3.8‰). The differences in δ18O and δ2H between the southern and northern waters are related to elevation that induced fractionation of oxygen and hydrogen isotopes in recharge water originated from coastal moisture. The data suggest that the high salinity in groundwater from the northern, western and eastern margins of the Lakhssas Plateau is related to the presence of schist rocks in these areas. The distinctive low Na/Cl and Br

  12. Diffusion in isotopically controlled semiconductor systems

    NASA Astrophysics Data System (ADS)

    Bracht, H.

    1999-12-01

    Isotopically controlled heterostructures of 28Si/natSi and Al71GaAs/Al69GaAs/71GaAs have been used to study the self-diffusion process in this elemental and compound semiconductor material. The directly measured Si self-diffusion coefficient is compared with the self-interstitial and vacancy contribution to self-diffusion which were deduced from metal diffusion experiments. The remarkable agreement between the Si self-diffusion coefficients and the individual contributions to self-diffusion shows that both self-interstitials and vacancies mediate Si self-diffusion. The Ga self-diffusion in undoped AlGaAs was found to decrease with increasing Al concentration. The activation enthalpy of Ga and Al diffusion in GaAs and of Ga diffusion in AlGaAs all lie in the range of (3.6±0.1) eV, but with different pre-exponential factors. The doping dependence of Ga self-diffusion reveals a retardation (enhancement) of Ga diffusion under p-type (n-type) doping compared to intrinsic conditions. All experimental results on the group-III atom diffusion are accurately described if vacancies on the group-III sublattice are assumed to mediate the Ga self- and Al-Ga interdiffusion in undoped AlGaAs and the Ga self-diffusion in Be- and Si-doped GaAs with an active dopant concentration of 3×1018 cm-3. The doping dependence of Ga self-diffusion in GaAs provides strong evidence that neutral, singly and doubly charged Ga vacancies govern the self-diffusion process.

  13. Groundwater transport of strontium 90 in a glacial outwash environment

    USGS Publications Warehouse

    Kipp, Kenneth L.; Stollenwerk, Kenneth G.; Grove, David B.

    1986-01-01

    As part of the investigation of groundwater contamination at a uranium-scrap recovery plant at Wood River Junction, Rhode Island, laboratory experiments led to the development of a model for predicting the transport of strontium 90 in glacial outwash sediments based on an approximate mechanism for ion exchange. The multicomponent system was simplified to two components by regarding all exchangeable cations other than strontium 90 as a single component. The binary ion-exchange parameter was a function of the variable, total ion concentration. A one-dimensional solute transport model was formulated to evaluate the time necessary for natural groundwater flow to remove the strontium 90 contamination plume from the groundwater system to the Pawcatuck River. The finite difference transport equations were solved sequentially for total ion concentrations, then strontium 90 concentrations. Clay-free quartz and feldspar sands at the study site have little potential for strontium 90 sorption, and high calcium, magnesium, and sodium concentrations compete for the few ion exchange sites. As the total ion concentration plume moves out of the system, ion exchange of strontium 90 increases, reducing the strontium 90 concentration in the groundwater. Cleanout times predicted using the binary ion exchange mechanism were about two thirds of those predicted using a constant distribution coefficient. It is suggested that this type of model can simulate solute transport more realistically in many groundwater systems where the total ion concentration is not constant.

  14. Groundwater Transport of Strontium 90 in a Glacial Outwash Environment

    NASA Astrophysics Data System (ADS)

    Kipp, Kenneth L., Jr.; Stollenwerk, Kenneth G.; Grove, David B.

    1986-04-01

    As part of the investigation of groundwater contamination at a uranium-scrap recovery plant at Wood River Junction, Rhode Island, laboratory experiments led to the development of a model for predicting the transport of strontium 90 in glacial outwash sediments based on an approximate mechanism for ion exchange. The multicomponent system was simplified to two components by regarding all exchangeable cations other than strontium 90 as a single component. The binary ion-exchange parameter was a function of the variable, total ion concentration. A one-dimensional solute transport model was formulated to evaluate the time necessary for natural groundwater flow to remove the strontium 90 contamination plume from the groundwater system to the Pawcatuck River. The finite difference transport equations were solved sequentially for total ion concentrations, then strontium 90 concentrations. Clay-free quartz and feldspar sands at the study site have little potential for strontium 90 sorption, and high calcium, magnesium, and sodium concentrations compete for the few ion exchange sites. As the total ion concentration plume moves out of the system, ion exchange of strontium 90 increases, reducing the strontium 90 concentration in the groundwater. Cleanout times predicted using the binary ion exchange mechanism were about two thirds of those predicted using a constant distribution coefficient. It is suggested that this type of model can simulate solute transport more realistically in many groundwater systems where the total ion concentration is not constant.

  15. Chromium isotopic fractionation in aquatic systems and foraminiferal calcite

    NASA Astrophysics Data System (ADS)

    Wang, X.; Wu, W.; Reinhard, C. T.; Planavsky, N.

    2016-12-01

    The stable chromium (Cr) isotope system is an emerging proxy for studying the reduction/oxidation (redox) state of the early earth. However, the distribution and isotopic composition of Cr in many modern environments is still poorly known. For this reason, Cr isotope fractionation during biological processes, in rivers, estuaries, seawaters, and modern sediments need to be constrained to calibrate this potentially very useful paleoredox proxy. Here we report concentrations and isotope systematics of dissolved and suspended Cr in the Connecticut River system, and from core-top planktonic foraminiferal calcite from the global ocean. In the Connecticut River system, soil profile samples are unfractionated from bulk silicate Earth (BSE) values. River waters range from -0.2‰ to 0.9‰ (δ53Cr expressed as 53Cr/52Cr relative to NIST SRM 979 standard), with some, but not all tributaries showing seasonal differences. Suspended particulate samples range from -0.1 to 0‰ in autumn and from 0 to 0.1‰ in spring. Modern planktonic foraminifera show a wide range of δ53Cr values, from 0.2‰ to 2.2‰. Such variability seems to be controlled by both seawater heterogeneity and biological fractionation. In summary, weathering environments studied so far suggest wide variability of δ53Cr in rivers and weathered rocks, but with indiscernible correlation with climate types (temperate vs. tropical). In addition, large spatial variability has been detected in the modern seawater and large biological fractionation has been observed during marine biological calcification. These observations provide important guidelines for interpreting the ancient Cr isotope record.

  16. Strontium-90 and promethium-147 recovery

    SciTech Connect

    Hoisington, J.E.; McDonell, W.R.

    1982-08-30

    Strontium-90 and promethium-147 are fission product radionuclides with potential for use as heat source materials in high reliability, non-interruptible power supplies. Interest has recently been expressed in their utilization for Department of Defense (DOD) applications. This memorandum summarizes the current inventories, the annual production rates, and the possible recovery of Sr-90 and Pm-147 from nuclear materials production operations at Hanford and Savannah River. Recovery of these isotopes from LWR spend fuel utilizing the Barnwell Nuclear Fuels Plant (BNFP) is also considered. Unit recovery costs at each site are provided.

  17. Quarterly report on the strontium heat source development program, Space and Terrestrial Systems Division for January-March 1981

    SciTech Connect

    Fullam, H.T.

    1981-05-01

    At Hanford, strontium is separated from the high-level waste, converted to the fluo-ride, and doubly encapsulated in small, high-integrity containers for subsequent long-term storage. The fluoride conversion, encapsulation, and storage takes place in the Waste Encapsulation and Storage Facilities (WESF). The encapsulated strontium fluoride represents an economical source of /sup 90/Sr if the WESF capsule can be licensed for heat-source applications under anticipated-use conditions. The objects of this program are to obtain the data needed to license /sup 90/SrF/sub 2/ heat sources and specifically the WESF /sup 90/SrF/sub 2/ capsules. The information needed for licensing can be divided into three general task areas: Task 1--Chemical and Physical Properties of /sup 90/SrF/sub 2/; Task 2--/sup 90/SrF/sub 2/ Compatibility Studies; and Task 3--Capsule Qualification and Licening. Efforts are proceeding concurrently on all three tasks to obtain the required information.

  18. New Approaches for Producing Quantum Degenerate Gases of Strontium

    NASA Astrophysics Data System (ADS)

    Ding, Roger; Woehl, Germano, Jr.; Camargo, Francisco; Whalen, Joseph; Dunning, F. Barry; Killian, Thomas

    2015-05-01

    We investigate two novel methods for laser cooling strontium to quantum degeneracy. The first takes advantage of the isotope shifts and the narrow 1S0 -3P1 intercombination line (7.5 kHz at 689 nm) to produce an isotope selective optical dipole trap (ODT). We demonstrate this technique by sympathetically cooling 88Sr or 87Sr using 86Sr to produce quantum degenerate gases. The second uses an acousto-optic modulator driven with multiple RF frequencies to dynamically shape a far-off resonance ODT. This is easy to implement in existing traps and allows for optimized loading and evaporation tailored for each isotope. The simple setup has been applied in various atomic physics experiments, and we describe its application in strontium. Research supported by the AFOSR under grant no. FA9550-12-1-0267, the NSF under grants nos. 1301773 and 1205946, and the Robert A. Welch Foundation under grant no. C-0734.

  19. Geochemical and isotopic characterization of groundwater origins in a Mediterranean karst system (southern France)

    NASA Astrophysics Data System (ADS)

    Seidel, J. L.; Ladouche, B.; Batiot-Guilhe, C.

    2013-12-01

    Geochemical and isotopic ratio (11B/10B and 87Sr/86Sr) results are reported for better determining the groundwater origins in the Lez Karst system (southern France). The Lez spring is the main perennial outlet of the system and supplies with drinking water the metropolitan area of Montpellier. According to the hydrodynamic conditions, five water-types discharge at the Lez spring with important mineralization fluctuations (Caetano Bicalho et al., 2012). This geochemical response suggests that hydrodynamics targets groundwater circulation, resulting from different water end-member solicitation and mixing. Previous studies using conventional natural tracers do not succeed to identify all the water compartments supporting the flow during the hydrologic cycle (Marjolet & Salado, 1977; Joseph et al., 1988) and to explain the mineralization variation of the Lez spring. The present study combines a basic geochemical survey data with boron and strontium isotope ratio data for a better characterization of the Lez spring geochemical functioning. Groundwater samples were collected at the Lez spring and surrounding springs and wells under different hydrologic conditions from 2009 to 2011. Major, trace and rare earth elements were determined at AETE analytical platform (OREME, Univ. Montpellier 2) by ionic chromatography and Q-ICP-MS respectively. d11B and 87Sr/86Sr were determined at BRGM/MMA Orleans by TIMS. The geochemical survey has been extended at a larger scale by sampling the main geochemical end- members already identified to replace the Lez spring waters in the regional geochemical context. From this geochemical study, valuable informations have been provided on the reservoir types and water origins flowing in high and low stage periods. For the highly mineralized waters occurring in the fall first rainy events or severe low stages, a deep contribution is highlighted but B and Sr isotopic data do not ascertain the two Triassic end-members (halite or gypsum) as possible

  20. Technology verification phase. Dynamic isotope power system. Final report

    SciTech Connect

    Halsey, D.G.

    1982-03-10

    The Phase I requirements of the Kilowatt Isotope Power System (KIPS) program were to make a detailed Flight System Conceptual Design (FSCD) for an isotope fueled organic Rankine cycle power system and to build and test a Ground Demonstration System (GDS) which simulated as closely as possible the operational characteristics of the FSCD. The activities and results of Phase II, the Technology Verification Phase, of the program are reported. The objectives of this phase were to increase system efficiency to 18.1% by component development, to demonstrate system reliability by a 5000 h endurance test and to update the flight system design. During Phase II, system performance was improved from 15.1% to 16.6%, an endurance test of 2000 h was performed while the flight design analysis was limited to a study of the General Purpose Heat Source, a study of the regenerator manufacturing technique and analysis of the hardness of the system to a laser threat. It was concluded from these tests that the GDS is basically prototypic of a flight design; all components necessary for satisfactory operation were demonstrated successfully at the system level; over 11,000 total h of operation without any component failure attested to the inherent reliability of this type of system; and some further development is required, specifically in the area of performance. (LCL)

  1. Component and system simulation models for High Flux Isotope Reactor

    SciTech Connect

    Sozer, A.

    1989-08-01

    Component models for the High Flux Isotope Reactor (HFIR) have been developed. The models are HFIR core, heat exchangers, pressurizer pumps, circulation pumps, letdown valves, primary head tank, generic transport delay (pipes), system pressure, loop pressure-flow balance, and decay heat. The models were written in FORTRAN and can be run on different computers, including IBM PCs, as they do not use any specific simulation languages such as ACSL or CSMP. 14 refs., 13 figs.

  2. Quality assurance program for isotopic power systems

    SciTech Connect

    Hannigan, R.L.; Harnar, R.R.

    1982-12-01

    This report summarizes the Sandia National Laboratories Quality Assurance Program that applies to non-weapon (reimbursable) Radioisotopic Thermoelectric Generators. The program has been implemented over the past 16 years on power supplies used in various space and terrestrial systems. The quality assurance (QA) activity of the program is in support of the Department of Energy, Office of Space Nuclear Projects. Basic elements of the program are described in the report and examples of program decumentation are presented.

  3. Quality assurance program for isotopic power systems

    NASA Astrophysics Data System (ADS)

    Hannigan, R. L.; Harnar, R. R.

    1982-12-01

    The Sandia National Laboratories Quality Assurance Program that applies to non-weapon (reimbursable) Radioisotopic Thermoelectric Generators is summarized. The program was implemented over the past 16 years on power supplies used in various space and terrestrial systems. The quality assurance (QA) activity of the program is in support of the Department of Energy, Office of Space Nuclear Projects. Basic elements of the program are described and examples of program documentation are presented.

  4. Local application of strontium in a calcium phosphate cement system accelerates healing of soft tissue tendon grafts in anterior cruciate ligament reconstruction: experiment using a rabbit model.

    PubMed

    Kuang, Guan-Ming; Yau, W P; Lu, William W; Chiu, K Y

    2014-12-01

    Healing of soft tissue tendon grafts within the bone tunnel in anterior cruciate ligament (ACL) reconstruction is known to be slower than that of bone-patellar tendon-bone grafts. There are attempts to accelerate healing of the graft within the bone tunnel. One of the methods is the use of strontium-enriched calcium phosphate cement (Sr-CPC). Early results in animal studies have been encouraging, although it is not known whether the accelerated healing was solely caused by the effect of strontium within the cement or by the calcium phosphate cement (CPC) itself. There would be differences between Sr-CPC and conventional CPC in terms of the effect on healing of soft tissue tendon grafts within the bone tunnels in ACL reconstruction. Controlled laboratory study. A total of 30 single-bundle ACL reconstruction procedures were performed in 15 rabbits with the use of an Achilles tendon allograft. The graft on the left limb was coated with Sr-CPC, while that on the right limb was coated with CPC. Three animals each were sacrificed for histological and histomorphometric analyses at 3, 6, 9, 12, and 24 weeks after surgery. In the Sr-CPC group, early formation of Sharpey fibers was present at 6 weeks after surgery, while early remodeling of a graft-fibrocartilage-bone junction was noted at 12 weeks. In the CPC group, early formation of Sharpey fibers was only found at 9 to 12 weeks after surgery. At 24 weeks, a direct enthesis was found in both groups. According to the histomorphometric score, graft healing in the Sr-CPC group took place 3 weeks faster than that in the CPC group at and before 12 weeks; however, there was no difference between the groups at 24 weeks. The local application of strontium in a CPC system leads to accelerated graft healing within the bone tunnels. The use of Sr-CPC to enhance graft-bone healing may improve the clinical results of ACL reconstruction using soft tissue tendon grafts. © 2014 The Author(s).

  5. Production of high-n strontium Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Ye, S.; Zhang, X.; Killian, T. C.; Dunning, F. B.; Hiller, M.; Yoshida, S.; Burgdörfer, J.

    2014-04-01

    The photoexcitation of strontium Rydberg atoms with n ~ 300 is being examined using a crossed laser-atom beam approach to enable study of quasi-stable two-electron excited states and of strongly-coupled Rydberg systems.

  6. On the mean oxygen isotope composition of the Solar System

    NASA Astrophysics Data System (ADS)

    Ozima, M.; Podosek, F. A.; Higuchi, T.; Yin, Q.-Z.; Yamada, A.

    2007-02-01

    Since the first discovery of extraordinary oxygen isotope compositions in carbonaceous meteorites by Clayton et al. [Clayton, R.N., Grossman, L., Mayeda, T.K., 1973. Science 182, 485-488], numerous studies have been done to explain the unusual mass-independent isotope fractionation, but the problem is still unresolved to this day. Clayton's latest interpretation [Clayton, R.N., 2002. Nature 415, 860-861] sheds new light on the problem, and possible hypotheses now seem to be fairly well defined. A key issue is to resolve whether the oxygen isotopes in the Solar System represented by the Sun (solar oxygen) are the same as oxygen isotopes in planetary objects such as bulk meteorites, Mars, Earth, and Moon, or whether the solar oxygen is more similar to the lightest oxygen isotopes observed in CAIs (Calcium Aluminum-rich Inclusions) in primitive meteorites. Here, we examined the problem using oxygen isotope analytical data of about 400 bulk meteorite samples of various classes or types (data compiled by K. Lodders). We used in our discussion exclusively the parameter Δ 17O, a direct measure of the degree of mass-independent isotope fractionation of oxygen isotopes. When Δ 17O is arranged according to a characteristic size of their host planetary object, it shows a systematic trend: (1) Δ 17O values scatter around zero; (2) the scatter from the mean (Δ 17O=0) decreases with increasing representative size of the respective host planetary object. This systematic trend is easily understood on the basis of a hierarchical scenario of planetary formation, that is, larger planetary objects have formed by progressive accretion of planetesimals by random sampling over a wide spectrum of proto-solar materials. If this progressive random sampling of planetesimals were the essential process of planetary formation, the isotopic composition of planetary oxygen should approach that of the solar oxygen. To test this random sampling hypothesis, we applied a multiscale, multistep

  7. Geochemistry, age and strontium isotope composition of late tertiary and quaternary basalts and andesites in western Nevada and their relation to geothermal potential. Final report, October 1, 1982-December 31, 1983

    SciTech Connect

    Fultz, L.A.; Bell, E.J.; Trexler, D.T.

    1984-01-01

    This research was undertaken to characterize the late Cenozoic volcanic rocks associated with active geothermal systems in west-central Nevada. Petrographic and microprobe, geochemical and isotopic analysis and age dating techniques were used to characterize these young volcanic rocks. These data were combined with the limited data previously reported in the literature on these same volcanic areas to interpret their petrogenesis. The overall characterization resulted from integrating the petrogenesis with a structural-tectonic model of the region. Potassium-argon isotopic ages ranging up to 14 million years were determined for eight localities within the Reno 1 x 2/sup 0/ study region. These ages are consistent with the morphology of the volcanic landforms, the active geothermal systems associated with them, and with other isotopic ages reported in the literature for these and similar rocks within the study region. Petrographic analysis of hand specimens and thin-sections indicated mineralogic assemblages of the respective rock types and specific mineral textures and phenocryst compositions and characteristics. These identifications were further substantiated by microprobe analysis of selected phenocrysts and groundmass phases. Classification of the respective rock types was also based on chemical composition and normative calculations using the program PETCAL. Basaltic andesites are identified and described for Steamboat Hills, Table Mountain, Silver Springs, Churchill Butte, Cleaver Peak, Desert Peak and Carson City sites.

  8. Experimental Constraints on Fe Isotope Fractionation in Carbonatite Melt Systems

    NASA Astrophysics Data System (ADS)

    Stuff, M.; Schuessler, J. A.; Wilke, M.

    2015-12-01

    Iron isotope data from carbonatite rocks show the largest variability found in igneous rocks to date [1]. Thus, stable Fe isotopes are promising tracers for the interaction of carbonate and silicate magmas in the mantle, particularly because their fractionation is controlled by oxidation state and bonding environment. The interpretation of Fe isotope data from carbonatite rocks remains hampered, since Fe isotope fractionation factors between silicate and carbonate melts are unknown and inter-mineral fractionation can currently only be assessed by theoretical calculations [1;2]. We present results from equilibration experiments in three natrocarbonatite systems between immiscible silicate and carbonate melts, performed at 1200°C and 0.7 GPa in an internally heated gas pressure vessel at intrinsic redox conditions. The Fe isotope compositions of the silicate melt (sil.m.), quenched to a glass, and the carbonate melt (carb.m.), forming fine-grained quench crystals, were analysed by solution MC-ICP-MS. Our first data indicate a remarkable fractionation of Δ56Fesil.m.‒carb.m.= 0.29 ±0.07 ‰ near equilibrium. At short run durations, even stronger fractionation up to Δ56Fesil.m.‒carb.m. = 0.41 ±0.07 ‰ occurs, due to kinetic effects. Additionally, Δ56Fesil.m.‒carb.m. changes with bulk chemical composition, likely reflecting considerable differences between the studied systems in terms of the Fe3+/Fe2+-ratios in the two immiscible liquids. Our findings provide experimental support for a carbonatite genesis model, in which extremely negative δ56Fe values in carbonatites result from differentiation processes, such as liquid immiscibility [1]. This effect can be enhanced by disequilibrium during fast ascent of carbonatite magmas. Their sensitivity to chemical and redox composition makes Fe isotopes a potential tool for constraining the original compositions of carbonatite magmas. [1] Johnson et al. (2010) Miner. Petrol. 98, 91-110. [2] Polyakov & Mineev (2000

  9. Observation System Simulation Experiment (OSSE) using water vapor isotopes

    NASA Astrophysics Data System (ADS)

    Yoshimura, K.

    2013-12-01

    Measurements of water vapor isotopes (δ18O and δD) have been drastically increased these years with new technology, i.e., spectroscopic instruments both satellite-onboard and ground-based (in-situ) to improve our understanding of the hydrologic cycle in the atmosphere and land surface. To more efficiently utilize these data, this study first developed a new data assimilation system with Local Transform Ensemble Kalman Filter (LETKF) and Isotope-incorporated Global Spectral Model (IsoGSM). Then an observation system simulation experiment (OSSE) was conducted. This OSSE uses a mock dataset of vapor isotope measurements, namely TES/Aura retrieved δD at mid-troposphere, SCIAMACHY/Envisat retrieved δD at vapor column, and virtual GNIP-like vapor isotope (both δD and δ18O) monitoring network. We used historical retrieval numbers for TES and SCIAMACHY measurements, which are 15,000 and 10,000 data in January 2006. For virtual GNIP-like network, we assumed about 200 sites over the world, and 6-hourly measurement at 2m from surface. The accuracy of the measurements are 10‰ and 100‰ for δ18O and δD, respectively, including the uncertainty associated with representativeness of the data in space and time. Then the OSSE with 20 ensemble member was conducted for January 2006. The results are indeed remarkable. It showed significant improvement in not only vapor isotopic field but also meteorological fields, such as wind speed, temperature, surface pressure and humidity, comparing with a test without any observation. For surface air temperature, the global RMSE has dropped 10%, in which as large as 40-60% decrease is observed in east-southeast Asia area where the observation concentration is relatively higher. Most of the variables showed consistently similar feature. These results clearly show that the vapor isotope measurement definitely help to improve our understanding of hydrologic cycle through constraining with the data assimilation. RMSE of 6-hourly data for 2

  10. Pb Isotopes as Tracers of Weathering in Glacial Systems

    NASA Astrophysics Data System (ADS)

    Martin, E. E.; Deuerling, K. M.; Scribner, C. A.; Martin, J. B.; Clements, K.

    2013-12-01

    Incongruent chemical weathering of freshly exposed continental material produces weathering solutions with Sr and Pb isotopic values that are distinctly more radiogenic than the parent material. As soils age, weathering becomes more congruent and the isotopic ratio in the solution approaches the composition of parent material. In light of this response, rapid increases in seawater Pb isotopes in the North Atlantic over the last deglacial have been attributed to incongruent weathering of fine grained glacial sediment exposed as the ice sheet retreated. This theory has not been tested using modern glacial river systems due to concerns about contamination by anthropogenic Pb. In this study we analyzed Pb isotopes from: 1) leachates of moraine material, 2) bedload and river water samples along a proglacial river, and 3) sediment and water samples from closed basin lakes in deglaciated terrains, from the Kangerlussuaq region of western Greenland. As expected, 0.1N HCl leachates of moraine soils exhibit 206,207,208Pb/204Pb ratios that are more radiogenic than the bulk soil. Samples from a Little Ice Age moraine close to the Russell Glacier exhibit greater offsets between the leachate and bulk soil Pb isotopes than samples from Orkendalen moraines (6.8 ka), which also record a slightly greater offset than Umivit-Keglen moraines (7.3 ka). Proglacial Watson (Akuliarusuarsuup Kuua) River water samples collected closest to the Russell Glacier also record the most radiogenic Pb isotopes and the largest increase relative to bedload values. Bedload 206Pb/204Pb ratios along the 40 km length of the proglacial river are 14.7+/0.6. Values for all water samples are distinctly more radiogenic than bedload, with the highest value (18.02) closest to the glacier and a general decreasing trend to ~15.82 farthest from the glacier. For comparison to anthropogenic Pb isotopes, 206Pb/207Pb ratios are 1.00+/-.03 for bedload, with water values ranging from 1.18 to 1.06 in a decreasing trend

  11. Boron isotope systematics of hydrothermal fluids from submarine hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Yamaoka, K.; Hong, E.; Ishikawa, T.; Gamo, T.; Kawahata, H.

    2013-12-01

    Boron is highly mobile in submarine hydrothermal systems and useful to trace the process of water-rock reaction. In this study, we measured the boron content and isotopic composition of vent fluids collected from arc-backarc hydrothermal systems in the western Pacific. In sediment-starved hydrothermal systems (Manus Basin, Suiyo Seamount, and Mariana Trough), the boron content and isotopic composition of vent fluids are dependent on type of host rock. The end member fluids from MORB-like basalt-hosted Vienna Woods in the Manus Basin showed low boron content and high δ11B value (0.53 mM, 29.8‰), while dacite-hosted PACMANUS and the Suiyo Seamount showed high boron contents and low δ11B values (1.45 and 1.52 mM, 13.6 and 18.5‰, respectively). The Alice Springs and Forecast Vent field in the Mariana Trough showed values intermediate between them (0.72 and 0.63 mM, 19.9 and 24.0‰, respectively), reflecting reaction of seawater and basalt influenced by slab material. In phase separated hydrothermal systems (North Fiji Basin), boron content and isotopic composition of vent fluids (0.44-0.56 mM, 34.5-35.9‰) were similar to those in the Vienna Woods. Considering little fractionation of boron and boron isotope during phase separation demonstrated by the previous experimental studies, it is suggested that the host rock in the North Fiji Basin is MORB-like basalt. In sediment-hosted hydrothermal system (Okinawa Trough), the reaction with boron-enriched sediment following seawater-rock reaction resulted in significantly high boron contents and low δ11B values of vent fluids (4.4-5.9 mM, 1.5-2.6‰). The water-sediment ratio was estimated to be ~2. In spite of the different geological settings, the end member fuids from all vent fields are enriched in B relative to seawater (0.41 mM, 39.6‰) and the δ11B values are inversely propotional to the boron concentrations. It suggests that boron isotopic composition of vent fluid predominantly depends on the amount of

  12. CHROMIUM ISOTOPE SYSTEMATICS OF ACHONDRITES: CHRONOLOGY AND ISOTOPIC HETEROGENEITY OF THE INNER SOLAR SYSTEM BODIES

    SciTech Connect

    Yamakawa, Akane; Yamashita, Katsuyuki; Makishima, Akio; Nakamura, Eizo

    2010-09-01

    The standard planetary formation models assume that primitive materials, such as carbonaceous chondrites, are the precursor materials of evolved planetesimals. Past chronological studies have revealed that planetesimals of several hundred kilometers in size, such as the Howardite-Eucrite-Diogenite (HED) parent body (Vesta) and angrite parent body, began their differentiation as early as {approx}3 million years of the solar system formation, and continued for at least several million years. However, the timescale of planetesimal formation in distinct regions of the inner solar system, as well as the isotopic characteristics of the reservoirs from which they evolved, remains unclear. Here we present the first report for the precise {sup 53}Mn-{sup 53}Cr ages of monomict ureilites. Chemically separated phases from one monomict ureilite (NWA 766) yielded the Mn-Cr age of 4564.60 {+-} 0.67 Ma, identical within error to the oldest age preserved in other achondrites, such as angrites and eucrites. The {sup 54}Cr isotopic data for this and seven additional bulk ureilites show homogeneous {epsilon}{sup 54}Cr of {approx}-0.9, a value distinct from other achondrites and chondrites. Using the {epsilon}{sup 54}Cr signatures of Earth, Mars, and Vesta (HED), we noticed a linear decrease in the {epsilon}{sup 54}Cr value with the heliocentric distance in the inner region of the solar system. If this trend can be extrapolated into the outer asteroid belt, the {epsilon}{sup 54}Cr signatures of monomict ureilites will place the position of the ureilite parent body at {approx}2.8 AU. These observations imply that the differentiation of achondrite parent bodies began nearly simultaneously at {approx}4565 Ma in different regions of the inner solar system. The distinct {epsilon}{sup 54}Cr value between ureilite and carbonaceous chondrite also implies that a genetic link commonly proposed between the two is unlikely.

  13. Strontium ranelate discontinued.

    PubMed

    2017-08-02

    Strontium ranelate discontinued ● Limited treatment options for molluscum contagiosum ● Finasteride drug safety alert ● Does doxycycline delay the next COPD exacerbation? ● Support for WHO standards on reporting clinical trial results ● Delayed antibiotic prescription for lower respiratory tract infections ● Nystatin dose change - much ado about nothing? Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  14. Producing Quantum Degenerate Gases of Strontium

    NASA Astrophysics Data System (ADS)

    Camargo, Francisco; Ding, Roger; Whalen, Joseph; Woehl, Germano; Dunning, Barry; Killian, Thomas

    2015-05-01

    We present our progress towards producing quantum degenerate gases of all four stable isotopes of strontium (84Sr, 86Sr, 87Sr, 88Sr) and isotopic mixtures. We characterize the performance of our broad-line (461 nm, 30.5 MHz), narrow-line (689 nm, 7.5 kHz) magneto-optical traps, and examine evaporative cooling for all four isotopes. The new apparatus will be used to create and study tunable long-range interactions by dressing with strongly-interacting Rydberg states. The ability to trap the four different isotopes allows a measure of control of these interactions through access to a range of attractive and repulsive interactions. Simultaneous trapping of different isotopes provides opportunities for novel laser cooling schemes for studying Bose-Bose and Bose-Fermi mixtures. Research supported by the AFOSR under grant no. FA9550-12-1-0267, the NSF under grants nos. 1301773 and 1205946, and the Robert A. Welch Foundation under grant no. C-0734.

  15. The TR13 control system for automatic isotope production

    NASA Astrophysics Data System (ADS)

    Dale, D. J.; Ewert, T.; Harrison, D.; Lam, J.; Keitel, R.

    1994-12-01

    The TR13 is a 13 MeV H cyclotron which produces short-lived isotopes for use in PET scanners. Machines of this type are usually installed in hospitals and call for automatic operation with a minimum of operator intervention and maintenance. The control system implementation follows the approach of the TR30 line of cyclotrons, using commercial software and hardware wherever possible. The two-processor system uses an Allen Bradley PLC for control and an IBM PC as console computer. Aspects of automatic operation are discussed in detail.

  16. NMR-based Stable Isotope Resolved Metabolomics in systems biochemistry.

    PubMed

    Lane, Andrew N; Fan, Teresa W-M

    2017-08-15

    Metabolism is the basic activity of live cells, and monitoring the metabolic state provides a dynamic picture of the cells or tissues, and how they respond to external changes, for in disease or treatment with drugs. NMR is an extremely versatile analytical tool that can be applied to a wide range of biochemical problems. Despite its modest sensitivity its versatility make it an ideal tool for analyzing biochemical dynamics both in vitro and in vivo, especially when coupled with its isotope editing capabilities, from which isotope distributions can be readily determined. These are critical for any analyses of flux in live organisms. This review focuses on the utility of NMR spectroscopy in metabolomics, with an emphasis on NMR applications in stable isotope-enriched tracer research for elucidating biochemical pathways and networks with examples from nucleotide biochemistry. The knowledge gained from this area of research provides a ready link to genomic, epigenomic, transcriptomic, and proteomic information to achieve systems biochemical understanding of living cells and organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Ca isotopic geochemistry of an Antarctic aquatic system

    NASA Astrophysics Data System (ADS)

    Lyons, W. Berry; Bullen, Thomas D.; Welch, Kathleen A.

    2017-01-01

    The McMurdo Dry Valleys, Antarctica, are a polar desert ecosystem. The hydrologic system of the dry valleys is linked to climate with ephemeral streams that flow from glacial melt during the austral summer. Past climate variations have strongly influenced the closed-basin, chemically stratified lakes on the valley floor. Results of previous work point to important roles for both in-stream processes (e.g., mineral weathering, precipitation and dissolution of salts) and in-lake processes (e.g., mixing with paleo-seawater and calcite precipitation) in determining the geochemistry of these lakes. These processes have a significant influence on calcium (Ca) biogeochemistry in this aquatic ecosystem, and thus variations in Ca stable isotope compositions of the waters can aid in validating the importance of these processes. We have analyzed the Ca stable isotope compositions of streams and lakes in the McMurdo Dry Valleys. The results validate the important roles of weathering of aluminosilicate minerals and/or CaCO3 in the hyporheic zone of the streams, and mixing of lake surface water with paleo-seawater and precipitation of Ca-salts during cryo-concentration events to form the deep lake waters. The lakes in the McMurdo Dry Valleys evolved following different geochemical pathways, evidenced by their unique, nonsystematic Ca isotope signatures.

  18. Towards Understanding Artifacts in the Clumped Isotope System

    NASA Astrophysics Data System (ADS)

    Swart, P. K.; Staudigel, P. T.; Murray, S.

    2015-12-01

    The clumped isotope system in carbonates (Δ47) relies on the extraction of CO2 from the carbonate minerals using phosphoric acid. Despite the fact that this method dates back to the original stable isotopic work in the 1950s, there are significant aspects of the fractionation of the 18O/16O (and by inference the ratio of mass 47 to 44) which are not understood. We believe that subtle variations in the isotopic fractionation as a function of temperature, acid density (and acid preparation method), and extraction line design cause variation between the clumped isotope data produced by different laboratories. One of the most obvious of these is difference in reaction temperatures. While most laboratories employ temperatures of between 75 and 90oC, the original method employed a temperature of 25oC. Although various estimate of the difference in fractionation of Δ47 between 25 and 90oC have been made, we have measured significantly different values for dolomites compared to published data. In order to understand this we have performed experiments in sealed Pyrex vessels to measure the exchange between CO2 and 103% phosphoric acid. We have determined there to be significant and measurable changes in the Δ47 of CO2 when exposed to phosphoric acid. This exchange is a function of temperature, time, acid strength, and the surface area of the acid exposed to the CO2. We postulate that, perhaps as a result of the lower reaction rate of dolomite, compared to calcite, that there is greater opportunity for CO2 to exchange with the phosphoric acid as bubbles of CO2 are retained within the acid for longer periods of time. Such a mechanism would predict that well-ordered dolomites will have different fractionation compared to protodolomite. Similar differences might account for different fractionation for other carbonate minerals.

  19. Chemical and Isotopic Fractionation by Diffusion in Silicate Systems

    NASA Astrophysics Data System (ADS)

    Richter, F. M.

    2006-12-01

    unit measured by Andrew Davis by SIMS) associated with the interdiffusion of basalt and rhyolite. We have now extended these studies to include isotopic fractionations of Mg and Fe, and have begun to explore the potential for similar isotopic fractionations by grain boundary diffusion. The grain boundary fractionation experiments are motivated by the recent report by Teng et al. that the Li that diffused from Tin Mountain pegmatite into a surrounding amphibolite is fractionated by up to 30° in a diffusive boundary layer. A further similarity of the Tin Mountain Li diffusion and what we found in our basalt- rhyolite couples, is that Li was found to be the fastest diffuser by far of all the elements that were analyzed. The fact that large kinetic isotope fractionations during chemical diffusion have now been documented in both laboratory experiments and in a natural setting, together with recent advances in the ease and precision with which stable isotopic compositions can be measured, suggests that a lot more attention should be paid to isotope fractionations as a fingerprint for diffusive transport in silicate systems.

  20. Interpretation of isotopic data in groundwater-rock systems: Model development and application to Sr isotope data from Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Johnson, Thomas M.; Depaolo, Donald J.

    1994-05-01

    A model enabling extraction of hydrologic information from spatial and temporal patterns in measurements of isotope ratios in water-rock systems is presented. The model describes the evolution of isotope ratios in response to solute transport and water-rock interaction. In advective systems, a single dimensionless parameter (a Damköhler number, ND) dominates in determining the distance over which isotopic equilibrium between the water and rock is approached. Some isotope ratios act as conservative tracers (ND ≪ 1), while others reflect only interaction with the local host rock (ND ≫ 1). If ND is close to one (i.e., the distance for equilibration is close to the length scale of observation), isotope ratio measurements can be used to determine ND, which in turn may yield information concerning reaction rates, or spatial variations in water velocity. Zones of high velocity (e.g., as a result of greater fracture density), or less reactive zones, may be identified through observation of their lower ND values. The model is applied to paleohydrologic interpretations of Sr isotope data from calcite fracture fillings in drill cores from Yucca Mountain, Nevada (Marshall et al., 1992). The results agree with other studies suggesting "fast path" transport in the unsaturated zone. Also, we find that the data do not give a conclusive indication of paleowater table elevation because of the effects of water-rock interaction.

  1. Flooding of lignite mines: isotope variations and processes in a system influenced by saline groundwater.

    PubMed

    Trettin, Rolf; Glässer, Walter; Lerche, Ian; Seelig, Ulrike; Treutler, Hanns-Christian

    2006-06-01

    The quality of both groundwaters and surface waters that arise during flooding of abandoned lignite open pits are influenced by regional and local factors. A typical regional factor is due to oxidised sedimentary sulfides. A more local factor is the interaction of shallow water with highly saline groundwater, which is important in Merseburg-Ost (Germany). Investigation of this system is aided by the use of many environmental isotope tracers but special problems can arise. In order to reveal processes in the mine environment (shallow groundwater, lake water) and to characterise mixtures with saline groundwater results are described using the tracers deltaD, delta18O, delta13C, delta34S, 87Sr/86Sr, 3H, 14C, 39Ar, and 222Rn. Deep highly saline groundwater had a radiocarbon concentration typically below 10 pMC. The values of delta13C(DIC) are around-5 per thousand. As delta13C of the aquifer rock samples (Permian, Zechstein carbonates) was in the range of-6...+5 per thousand, residence time corrections based on delta13C are questionable. Additional checks with 39Ar, as well as results from the variationof delta18O (or deltaD) with respect to the salinity, emphasise a Holocene age; as is also the case for most mineralised groundwaters and also for water having a low delta18O (and deltaD). For saline groundwater residing in the Zechstein aquifer the measured delta34S values of about 12 per thousand are close to those expected from the literature. In contrast, the 87Sr/86Sr ratio of dissolved strontium is far from the values anticipated for the aquifer rocks despite there being proportionality between the chloride concentration and the strontium concentration. Furthermore, the proportionality is not valid in lower mineralised water. The 87Sr/86Sr ratio can, therefore, hardly be used as a tracer for the distribution of ascending saline water. The amount of salt-water coming from below into the residual quarry basins is an essential contribution to the lake inventories

  2. Effect of strontium ranelate on bone mineral: Analysis of nanoscale compositional changes.

    PubMed

    Rossi, André L; Moldovan, Simona; Querido, William; Rossi, Alexandre; Werckmann, Jacques; Ersen, Ovidiu; Farina, Marcos

    2014-01-01

    Strontium ranelate has been used to prevent bone loss and stimulate bone regeneration. Although strontium may integrate into the bone crystal lattice, the chemical and structural modifications of the bone when strontium interacts with the mineral phase are not completely understood. The objective of this study was to evaluate apatite from the mandibles of rats treated with strontium ranelate in the drinking water and compare its characteristics with those from untreated rats and synthetic apatites with and without strontium. Electron energy loss near edge structures from phosphorus, carbon, calcium and strontium were obtained by electron energy loss spectroscopy in a transmission electron microscope. The strontium signal was detected in the biological and synthetic samples containing strontium. The relative quantification of carbon by analyzing the CK edge at an energy loss of ΔE = 284 eV showed an increase in the number of carbonate groups in the bone mineral of treated rats. A synthetic strontium-containing sample used as control did not exhibit a carbon signal. This study showed physicochemical modifications in the bone mineral at the nanoscale caused by the systemic administration of strontium ranelate.

  3. New Isotopic Tracers for Shale Gas and Hydraulic Fracturing Fluids

    EPA Pesticide Factsheets

    The combined application of geochemistry, stable isotopes (δ18O, δ2H), strontium isotopes (87Sr/86Sr), boron isotopes (δ11B), and radium isotopes (228Ra/226Ra) provides a unique methodology for tracing and monitoring shale gas and fracking fluids in the environment.

  4. Silicon Isotopic Fractionation in a Tropical Soil-Plant System

    NASA Astrophysics Data System (ADS)

    Opfergelt, S.; Delstanche, S.; Cardinal, D.; Andre, L.; Delvaux, B.

    2006-12-01

    Silica fluxes to soil solutions and water streams are controlled by both abiotic and biotic processes occurring in a Si soil-plant cycle that can be significant in comparison with Si weathering input and hydrological output. The quantification of Si-isotopic fractionation by these processes is highly promising to study the Si soil-plant cycle. Therein, the fate of aqueous monosilicic acid H4SiO4, as produced by silicate weathering, may take four paths: (1) uptake by plants and recycling through falling litter, (2) formation of clay minerals, (3) specific adsorption onto Al and Fe oxides, (4) leaching in drainage waters and export from watersheds. Here we report on detailed Si-isotopic compositions of various Si pools in a tropical soil-plant system involving old stands of banana (Musa acuminata Colla, cv Grande Naine) cropped on a weathering sequence of soils derived from andesitic volcanic ash and pumice deposits in Cameroon, West Africa. Si-isotopic compositions were measured by MC-ICP-MS in dry plasma mode with external Mg doping with a reproducibility of 0.08 permil (2stdev). Results were expressed as delta29Si vs NBS28. The compositions were determined in plant parts, bulk soils, clay fractions (less than 2um) and stream waters used for crop irrigation. Of the weathering sequence, we selected young (Y) and old (O) volcanic soils (vs). Yvs are rich in weatherable minerals, and contain large amounts of pumice gravels; their clay fraction (10-35 percent) contains allophane, halloysite and ferrihydrite. Oppositely, Ovs are strongly weathered and fine clayey soils (75-96 percent clay) rich in halloysite, kaolinite, gibbsite and goethite. Intra-plant fractionation between roots and shoots and within shoots confirmed our previous data measured on banana plants grown in hydroponics. The bulk plant isotopic composition was heavier at Ovs than at Yvs giving a fractionation factor per atomic mass unit between plants and their irrigation water Si source (+0.61 permil) of

  5. Development of the detector system for β -decay spectroscopy at the KEK Isotope Separation System

    NASA Astrophysics Data System (ADS)

    Kimura, S.; Ishiyama, H.; Miyatake, H.; Hirayama, Y.; Watanabe, Y. X.; Jung, H. S.; Oyaizu, M.; Mukai, M.; Jeong, S. C.; Ozawa, A.

    2016-06-01

    The KEK Isotope Separation System has been developed to study the β -decay properties of the neutron-rich nuclei around the neutron magic number N = 126. These properties are essential for understanding the origin of the third peak in the r-process element abundance pattern. The detector system for β -decay spectroscopy at the KEK Isotope Separation System should have high detection efficiency for low-energy β -rays, and should be operated under a low-background environment. The detector system of the KEK Isotope Separation System consists of β -ray telescopes and a tape transport system. The solid angle covered by the β -ray telescopes is as large as 75% of 4 π in total. The Qβ -value dependence of the detection efficiency was estimated by Geant4 simulation. The background rate was 0.09 cps using a veto counter system and Pb shields. This background rate allows us to measure the lifetime of 202Os.

  6. DRESS syndrome with autoimmune hepatitis from strontium ranelate.

    PubMed

    di Meo, Nicola; Gubertini, Nicoletta; Crocè, Lory; Tiribelli, Claudio; Trevisan, Giusto

    2016-05-01

    Strontium ranelate, which is used for postmenopausal osteoporosis, has been associated with drug rash with eosinophilia and systemic symptoms (DRESS) syndrome, a severe, acute, potentially fatal, multisystem adverse drug reaction characterized by skin rash, fever, hematological abnormalities, and lymphadenopathy with involvement of several internal organs. We report the case of a woman who developed DRESS syndrome with a generalized maculopapular rash, eosinophilia, dyspnea, bilateral cervical lymphadenopathy, and reactivation of Epstein-Barr virus (EBV) with liver damage 3 weeks after administration of strontium ranelate for postmenopausal osteoporosis. Approximately 6 months after total remission of cutaneous symptoms, the patient developed autoimmune hepatitis. This case confirms that strontium ranelate should be considered as a possible factor in the etiopathology of DRESS syndrome as well as in the subsequent development of autoimmune hepatitis. The possibility of developing autoimmune hepatitis as a part of DRESS syndrome related to strontium ranelate use can occur months after the acute episode.

  7. Isotopic Biogeochemistry

    NASA Technical Reports Server (NTRS)

    Hayes, J. M.

    1985-01-01

    An overview is provided of the biogeochemical research. The funding, productivity, personnel and facilities are reviewed. Some of the technical areas covered are: carbon isotopic records; isotopic studies of banded iron formations; isotope effects in microbial systems; studies of organic compounds in ancient sediments; and development in isotopic geochemistry and analysis.

  8. Presynaptic strontium dynamics and synaptic transmission.

    PubMed

    Xu-Friedman, M A; Regehr, W G

    1999-04-01

    Strontium can replace calcium in triggering neurotransmitter release, although peak release is reduced and the duration of release is prolonged. Strontium has therefore become useful in probing release, but its mechanism of action is not well understood. Here we study the action of strontium at the granule cell to Purkinje cell synapse in mouse cerebellar slices. Presynaptic residual strontium levels were monitored with fluorescent indicators, which all responded to strontium (fura-2, calcium orange, fura-2FF, magnesium green, and mag-fura-5). When calcium was replaced by equimolar concentrations of strontium in the external bath, strontium and calcium both entered presynaptic terminals. Contaminating calcium was eliminated by including EGTA in the extracellular bath, or by loading parallel fibers with EGTA, enabling the actions of strontium to be studied in isolation. After a single stimulus, strontium reached higher peak free levels than did calcium (approximately 1.7 times greater), and decayed more slowly (half-decay time 189 ms for strontium and 32 ms for calcium). These differences in calcium and strontium dynamics are likely a consequence of greater strontium permeability through calcium channels, lower affinity of the endogenous buffer for strontium, and less efficient extrusion of strontium. Measurements of presynaptic divalent levels help to explain properties of release evoked by strontium. Parallel fiber synaptic currents triggered by strontium are smaller in amplitude and longer in duration than those triggered by calcium. In both calcium and strontium, release consists of two components, one more steeply dependent on divalent levels than the other. Strontium drives both components less effectively than does calcium, suggesting that the affinities of the sensors involved in both phases of release are lower for strontium than for calcium. Thus, the larger and slower strontium transients account for the prominent slow component of release triggered by

  9. Presynaptic strontium dynamics and synaptic transmission.

    PubMed Central

    Xu-Friedman, M A; Regehr, W G

    1999-01-01

    Strontium can replace calcium in triggering neurotransmitter release, although peak release is reduced and the duration of release is prolonged. Strontium has therefore become useful in probing release, but its mechanism of action is not well understood. Here we study the action of strontium at the granule cell to Purkinje cell synapse in mouse cerebellar slices. Presynaptic residual strontium levels were monitored with fluorescent indicators, which all responded to strontium (fura-2, calcium orange, fura-2FF, magnesium green, and mag-fura-5). When calcium was replaced by equimolar concentrations of strontium in the external bath, strontium and calcium both entered presynaptic terminals. Contaminating calcium was eliminated by including EGTA in the extracellular bath, or by loading parallel fibers with EGTA, enabling the actions of strontium to be studied in isolation. After a single stimulus, strontium reached higher peak free levels than did calcium (approximately 1.7 times greater), and decayed more slowly (half-decay time 189 ms for strontium and 32 ms for calcium). These differences in calcium and strontium dynamics are likely a consequence of greater strontium permeability through calcium channels, lower affinity of the endogenous buffer for strontium, and less efficient extrusion of strontium. Measurements of presynaptic divalent levels help to explain properties of release evoked by strontium. Parallel fiber synaptic currents triggered by strontium are smaller in amplitude and longer in duration than those triggered by calcium. In both calcium and strontium, release consists of two components, one more steeply dependent on divalent levels than the other. Strontium drives both components less effectively than does calcium, suggesting that the affinities of the sensors involved in both phases of release are lower for strontium than for calcium. Thus, the larger and slower strontium transients account for the prominent slow component of release triggered by

  10. Lithium isotope traces magmatic fluid in a seafloor hydrothermal system

    PubMed Central

    Yang, Dan; Hou, Zengqian; Zhao, Yue; Hou, Kejun; Yang, Zhiming; Tian, Shihong; Fu, Qiang

    2015-01-01

    Lithium isotopic compositions of fluid inclusions and hosted gangue quartz from a giant volcanogenic massive sulfide deposit in China provide robust evidence for inputting of magmatic fluids into a Triassic submarine hydrothermal system. The δ7Li results vary from +4.5‰ to +13.8‰ for fluid inclusions and from +6.7‰ to +21.0‰ for the hosted gangue quartz(9 gangue quartz samples containing primary fluid inclusions). These data confirm the temperature-dependent Li isotopic fractionation between hydrothermal quartz and fluid (i.e., Δδ7Liquartz-fluid = –8.9382 × (1000/T) + 22.22(R2 = 0.98; 175 °C–340 °C)), which suggests that the fluid inclusions are in equilibrium with their hosted quartz, thus allowing to determine the composition of the fluids by using δ7Liquartz data. Accordingly, we estimate that the ore-forming fluids have a δ7Li range from −0.7‰ to +18.4‰ at temperatures of 175–340 °C. This δ7Li range, together with Li–O modeling , suggest that magmatic fluid played a significant role in the ore formation. This study demonstrates that Li isotope can be effectively used to trace magmatic fluids in a seafloor hydrothermal system and has the potential to monitor fluid mixing and ore-forming process. PMID:26347051

  11. Sulfur isotope fractionation in modern euxinic systems: Implications for paleoenvironmental reconstructions of paired sulfate-sulfide isotope records

    NASA Astrophysics Data System (ADS)

    Gomes, Maya L.; Hurtgen, Matthew T.

    2015-05-01

    The sulfur (S) isotope difference between sulfates and sulfides preserved in sedimentary rocks (Δ34S) has been utilized to reconstruct ancient marine sulfate levels with implications for oxygenation of the Earth surface and biogeochemical cycling. S isotope data from modern, low-sulfate euxinic systems illustrate that preserved Δ34S values are positively correlated with sulfate concentration. However, absolute constraints on the range of low-sulfate levels over which preserved Δ34S values vary with sulfate concentration remain poorly constrained. Here, we present a compilation of S isotope data for modern euxinic systems demonstrating that preserved Δ34S values increase with sulfate concentration at low sulfate levels and approach values that are similar to in situ S isotope fractionation values from microbial sulfate reduction at high sulfate levels. We compare these results to a closed system model of S isotope cycling in a euxinic ocean in order to evaluate when the size of the sulfate reservoir is sufficiently small that Rayleigh fractionation affects the preservation of S isotope signatures. We conclude that the reservoir effect places constraints on Δ34S values deposited in euxinic settings at sulfate concentrations <5 mM. Thus, over this range, Δ34S values can be used to evaluate ancient sulfate levels. At higher sulfate levels (>10 mM), Δ34S values are similar to the kinetic isotope fractionation due to microbial sulfate reduction and therefore provide information about biological and environmental controls on sulfate reduction rates and location of pyrite formation. The results of this compilation provide an improved model for the use of Δ34S records to evaluate paleoenvironmental conditions in euxinic depositional environments.

  12. Interferometry with Strontium Ions

    NASA Astrophysics Data System (ADS)

    Jackson, Jarom; Lambert, Enoch; Otterstrom, Nils; Jones, Tyler; Durfee, Dallin

    2014-05-01

    We describe progress on a cold ion matter-wave interferometer. Cold Strontium atoms are extracted from an LVIS. The atoms will be photo-ionized with a two-photon transition to an auto-ionizing state in the continuum. The ions will be split and recombined using stimulated Raman transitions from a pair of diode lasers injection locked to two beams from a master laser which have been shifted up and down by half the hyperfine splitting. We are developing laser instrumentation for this project including a method to prevent mode-hopping by analyzing laser frequency noise, and an inexpensive, robust wavelength meter. Supported by NSF Award No. 1205736.

  13. An EBIS system for rare isotope science project in Korea

    SciTech Connect

    Kim, Jongwon E-mail: jehan@ibs.re.kr E-mail: khyi@ibs.re.kr; Han, Jae-Eun E-mail: jehan@ibs.re.kr E-mail: khyi@ibs.re.kr; Son, Hyock-Jun E-mail: jehan@ibs.re.kr E-mail: khyi@ibs.re.kr; Yi, Kun-Hui E-mail: jehan@ibs.re.kr E-mail: khyi@ibs.re.kr; Zhao, Liangji E-mail: kim@far-tech.com; Kim, Jin-Soo E-mail: kim@far-tech.com

    2015-01-09

    An EBIS system has been designed to be used as a charge breeder for the post accelerator of an ISOL system. An electron gun, which is designed to produce a maximum current of 3 A at the beam energy of 20 kV, will be acquired from the Budker Institute, Novosibirsk. Electron beam optics calculations of the EBIS system as well as of the gun assembly have been performed using PBGUNS and TRAK. A superconducting solenoid with a maximum field of 6 T is to be used to compress the electron beam. A test stand, which includes the gun assembly and a high-power electron beam collector, is being designed and will be ready for the gun test in the end of this year. Charge breeding simulation using EBIS0D and CBSIM has been performed for a few key isotopes.

  14. Isotopic abundances - Inferences on solar system and planetary evolution

    NASA Astrophysics Data System (ADS)

    Wasserburg, G. J.

    1987-12-01

    For matter that has been removed from a region of nucleosynthetic activity and the effects of interactions with nuclear active particles, the only changes in nuclear abundances that can occur in an isolated system derive from the decay of radioactive nuclei of an element to yield the nucleus of another element. These two related nuclei furnish the absolute chronometers of geologic and cosmic time, through the decay of spontaneously radioactive parent nuclei and the accumulation of daughter nuclei. For systems related to such cosmic processes as the formation of the solar system from the precursor interstellar medium, and involving the very early evolution of the sun, there may arise considerable complexity, due to the intrinsic isotopic heterogeneity of the medium and the presence of short-lived nuclei.

  15. Phase Stability of the Lanthanum Strontium Manganites

    NASA Astrophysics Data System (ADS)

    Zheng, Feng; Pederson, Larry

    1996-03-01

    Phase diagram and thermodynamic data of the La-Sr-Mn-O system has been studied. The ABO3 -type perovskite of this system is presently the preferred cathode material for application in solid oxide fuel cells. And the phase stability of the lanthanum strontium manganites at elevated temperature is vital to fuel cell operation. Measuring the electromotive force through solid galvanic cell (-) Air,Pt|SrF_2,SrO||CaF_2||La_1-xSr_xMnO_3,SrF_2|Pt,Air (+) and the like enable us to derive the strontium oxide activity and other thermodynamic parameters such as Gibbs free energy of reaction, etc, which help us to understand the materials in using.

  16. Strontium- and zinc-alginate hydrogels for bone tissue engineering.

    PubMed

    Place, Elsie S; Rojo, Luis; Gentleman, Eileen; Sardinha, José P; Stevens, Molly M

    2011-11-01

    The development of bone replacement materials is an important healthcare objective due to the drawbacks of treating defects with bone autografts. In this work we propose a bone tissue engineering approach in which arginine-glycine-aspartic acid (RGD)-modified alginate hydrogels are crosslinked with bioactive strontium and zinc ions as well as calcium. Strontium was chosen for its ability to stimulate bone formation, and zinc is essential for alkaline phosphatase (ALP) activity. Calcium and strontium gels had similar stiffnesses but different stabilities over time. Strontium gels made with alginate with a high percentage of guluronic acid residues (high G) were slow to degrade, whereas those made with alginate rich in mannuronic acid (high M) degraded more quickly, and supported proliferation of Saos-2 osteoblast-like cells. After an initial burst, strontium release from alginate gels was steady and sustained, and the magnitude of release from high M gels was biologically relevant. Saos-2 cultured within alginate gels upregulated the osteoblast phenotypic marker genes RUNX2, collagen I (COL1A1) and bone sialoprotein (BSP), and ALP protein activity was highest in alginate gels cast with strontium ions. This strategy has the potential to be combined with other alginate-based systems for bone tissue engineering, or adapted to other tissue engineering applications.

  17. Thermoelectricity in strontium titanate

    NASA Astrophysics Data System (ADS)

    Scullin, Matthew Leo

    This dissertation treats the synthesis, experimental characterization, thermoelectric properties, potential applications of, and theoretical basis for strontium titanate thermoelectric materials. It is found that doubly-doped strontium titanate, Sr1-xLaxTiO3-d is an efficient n-type thermoelectric material, yielding a dimensionless thermoelectric figure of merit zT higher than other oxides and among the highest of any thermoelectric material in general. The improvement in thermoelectric efficiency of this material over other oxides is attributed in large part to the oxygen vacancy, which increases the electronic effective mass m* and in turn thermopower, increases electrical conductivity through donating electrons, and decreases lattice thermal conductivity. Through proper selection of La and oxygen vacancy doping, m* can be tuned in the material in the range of 2-20 me and thermal conductivity reduced by over a factor of three compared to stoichiometric SrTiO3. The potential applications of thin-film thermoelectrics in energy conversion are explored. In addition, the remarkable oxygen reduction of SrTiO3 single-crystal substrates is reported as resulting from pulsed laser deposition growth of oxide thin-films on their surfaces.

  18. Boron implanted strontium titanate

    NASA Astrophysics Data System (ADS)

    Cooper, C. J. M.

    Single crystals of strontium titanate implanted with boron were found to have highly conductive surface layers. The effects of varying dose from 10 to the 16th power to 10 to the 17th power ions/sq cm, implantation voltage from 50 to 175 keV and annealing conditions on the room temperature surface resistance and Hall mobility are presented. Variation of the implantation voltage did not have a major effect on the sheet resistances obtained by boron implantation of strontium titanate, while dose and annealing conditions have major effects. Doses of 5 x 10 to the 16th power ions/sq cm required annealing on the order of one hour at 500 K for maximum reduction of the room temperature resistance in the implanted layer. Samples implanted with a dose of 1 x 10 to the 17th power ions/sq cm required slightly higher temperatures (approximately 575 K) to obtain a minimum resistance at room temperature. Long term (several weeks) room temperature annealing was found to occur in high dose samples. After one to two months at room temperature followed by an anneal to 575 K, the surface resistances were found to be lower than those produced by the annealing of a freshly implanted sample to 575 K.

  19. Isotope heat source simulator for testing of space power systems

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Smith, R. B.

    1973-01-01

    A reliable isotope heat source simulator was designed for use in a Brayton power system. This simulator is composed of an electrically heated tungsten wire which is wound around a boron nitride core and enclosed in a graphite jacket. Simulator testing was performed at the expected operating temperature of the Brayton power system. Endurance testing for 5012 hours was followed by cycling the simulator temperature. The integrity of this simulator was maintained throughout testing. Alumina beads served as a diffusion barrier to prevent interaction between the tungsten heater and boron nitride core. The simulator was designed to maintain a surface temperature of 1311 to 1366 K (1900 to 2000 F) with a power input of approximately 400 watts. The design concept and the materials used in the simulator make possible man different geometries. This flexibility increases its potential use.

  20. Calibration of the 125I-induced X-ray fluorescence spectrometry-based system of in vivo bone strontium determinations using hydroxyapatite as a phantom material: A simulation study.

    PubMed

    Da Silva, Eric; Pejovic-Milic, Ana

    2017-03-01

    The calibration of in vivo X-ray fluorescence systems of bone strontium quantification, based on 125I excitation, is dependent on a coherent normalization procedure. Application of this procedure with the use of plaster of Paris (poP) as a phantom material requires the application of a coherent conversion factor (CCF) to make the calibration functions transferable between the phantom material and human bone. In this work we evaluate, with the use of Monte Carlo simulation, the potential benefit of employing a newly developed hydroxyapatite phantom material into the calibration protocol. Simulations being performed on bare bone phantoms, as the emission spectrum in this case is equivalent to an emission spectrum of an adequately corrected measurement for soft tissue attenuation of emitted strontium signal. We report that the application of hydroxyapatite phantoms does in fact remove the need for a coherent correction factor (CCF). The newly developed phantoms can thus be used for the calibration of in vivo bone strontium systems removing one step of the calibration protocol. Calibration is however limited to cases in which the concentration is relative to the amount of calcium in the specimen, which is, the most useful quantity in a clinical sense. Determining concentrations on a per-mass-of-material basis, that is, a concentration not normalized to the calcium content of the phantom/bone, results in large biases in estimated bone strontium content. The use of an HAp phantom material was found to remove the need for a CCF. It was also found that in the case of an incomplete conversion ratio when preparing the phantom material that there would be little effect on the differential coherent cross-section and thereby the coherent normalization-based calibration protocol.

  1. Boron isotope variations in geothermal systems on Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Purnomo, Budi Joko; Pichler, Thomas; You, Chen-Feng

    2016-02-01

    This paper presents δ11B data for hot springs, hot acid crater lakes, geothermal brines and a steam vent from Java, Indonesia. The processes that produce a large range of the δ11B values were investigated, including the possible input of seawater as well as the contrast δ11B compositions of acid sulfate and acid chloride crater lakes. The δ11B values of hot springs ranged from - 2.4 to + 28.7‰ and acid crater lakes ranged from + 0.6 to + 34.9‰. The δ11B and Cl/B values in waters from the Parangtritis and Krakal geothermal systems confirmed seawater input. The δ11B values of acid sulfate crater lakes ranged from + 5.5 to + 34.9‰ and were higher than the δ11B of + 0.6‰ of the acid chloride crater lake. The heavier δ11B in the acid sulfate crater lakes was caused by a combination of vapor phase addition and further enrichment due to evaporation and B adsorption onto clay minerals. In contrast, the light δ11B of the acid chloride crater lake was a result of acid water-rocks interaction. The correlations of δ11B composition with δ18O and δ2H indicated that the B isotope corresponded to their groundwater mixing sources, but not for J21 (Segaran) and J48 (Cikundul) that underwent 11B isotope enrichment by B adsorption into minerals.

  2. Small Stirling dynamic isotope power system for robotic space missions

    NASA Technical Reports Server (NTRS)

    Bents, D. J.

    1992-01-01

    The design of a multihundred-watt Dynamic Isotope Power System (DIPS), based on the U.S. Department of Energy (DOE) General Purpose Heat Source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE), is being pursued as a potential lower cost alternative to radioisotope thermoelectric generators (RTG's). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions ranging from scientific probes to Space Exploration Initiative precursor missions. Power level for these missions is less than a kilowatt. The incentive for any dynamic system is that it can save fuel and reduce costs and radiological hazard. Unlike DIPS based on turbomachinery conversion (e.g. Brayton), this small Stirling DIPS can be advantageously scaled to multihundred-watt unit size while preserving size and mass competitiveness with RTG's. Stirling conversion extends the competitive range for dynamic systems down to a few hundred watts--a power level not previously considered for dynamic systems. The challenge for Stirling conversion will be to demonstrate reliability and life similar to RTG experience. Since the competitive potential of FPSE as an isotope converter was first identified, work has focused on feasibility of directly integrating GPHS with the Stirling heater head. Thermal modeling of various radiatively coupled heat source/heater head geometries has been performed using data furnished by the developers of FPSE and GPHS. The analysis indicates that, for the 1050 K heater head configurations considered, GPHS fuel clad temperatures remain within acceptable operating limits. Based on these results, preliminary characterizations of multihundred-watt units have been established.

  3. Strontium-90 fluoride data sheet

    SciTech Connect

    Fullam, H.T.

    1981-06-01

    This report is a compilation of available data and appropriate literature references on the properties of strontium-90 fluoride and nonradioactive strontium fluoride. The objective of the document is to compile in a single source pertinent data to assist potential users in the development, licensing, and use of /sup 90/SrF/sub 2/-fueled radioisotope heat sources for terrestrial power conversion and thermal applications. The report is an update of the Strontium-90 Fluoride Data Sheet (BNWL-2284) originally issued in April 1977.

  4. The questa magmatic system: Petrologic, chemical and isotopic variations in cogenetic volcanic and plutonic rocks of the latir volcanic field and associated intrusives, northern New Mexico

    SciTech Connect

    Johnson, C.M.

    1986-01-01

    Field, chemical and isotopic data demonstrate that nearly all igneous rocks at Questa resulted from interactions between mantle-derived parental magmas and the crust. Strontium, neodymium and lead isotope ratios of early andesites to rhyolites (28 to 26 Ma) indicate that these magmas assimilated > 25% lower crust. Injection of basaltic magmas extensively modified the strontium and neodymium but not the lead isotope compositions of the lower crust. Eruption of comendite magmas and the peralkaline Amalia Tuff 26 Ma is correlated with inception of regional extension. Lead isotope ratios identify different sources for the metaluminous granites and the peralkaline rocks. 26 Ma metaluminous granite to granodiorite intrusions have chemical and isotopic compositions to those of the precaldera intermediate-composition rocks, and are interpreted as representing the solidified equivalents of the precaldera magmatic episode. However, both conventional and ion-microprobe isotopic data prohibit significant assimilation of crustal rocks at the level of exposure, suggesting that the plutons were emplaced a relatively crystal-rich mushes which did not have sufficient heat to assimilate country rocks. This suggest that in some cases plutonic rocks are better than volcanic rocks in representing the isotopic compositions of their source regions, because the assimilation potential of crystal-rich magmas is significantly less than that of largely liquid magmas.

  5. ON THE OXYGEN ISOTOPIC COMPOSITION OF THE SOLAR SYSTEM

    SciTech Connect

    Gaidos, Eric; Krot, Alexander N.; Huss, Gary R. E-mail: sasha@higp.hawaii.ed

    2009-11-10

    The {sup 18}O/{sup 17}O ratio of the solar system is 5.2 while that of the interstellar medium (ISM) and young stellar objects is approx4. This difference cannot be explained by pollution of the Sun's natal molecular cloud by {sup 18}O-rich supernova ejecta because (1) the necessary B-star progenitors live longer than the duration of star formation in molecular clouds, (2) the delivery of ejecta gas is too inefficient and the amount of dust in supernova ejecta is too small compared to the required pollution (2% of total mass or approx20% of oxygen), and (3) the predicted amounts of concomitant short-lived radionuclides (SLRs) conflicts with the abundances of {sup 26}Al and {sup 41}Ca in the early solar system. Proposals for the introduction of {sup 18}O-rich material must also be consistent with any explanation for the origin of the observed slope-one relationship between {sup 17}O/{sup 16}O and {sup 18}O/{sup 16}O in the high-temperature components of primitive meteorites. The difference in {sup 18}O/{sup 17}O ratios can be explained by enrichment of the ISM by the {sup 17}O-rich winds of asymptotic giant branch (AGB) stars, the sequestration of comparatively {sup 18}O-rich gas from star-forming regions into long-lived, low-mass stars, and a monotonic decrease in the {sup 18}O/{sup 17}O ratio of interstellar gas. At plausible rates of star formation and gas infall, Galactic chemical evolution does not follow a slope-one line in a three-isotope plot, but instead moves along a steeper trajectory toward an {sup 17}O-rich state. Evolution of the ISM and star-forming gas by AGB winds also explains the difference in the carbon isotope ratios of the solar system and ISM.

  6. Fundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems

    USGS Publications Warehouse

    Ni, Y.; Ma, Q.; Ellis, G.S.; Dai, J.; Katz, B.; Zhang, S.; Tang, Y.

    2011-01-01

    Based on quantum chemistry calculations for normal octane homolytic cracking, a kinetic hydrogen isotope fractionation model for methane, ethane, and propane formation is proposed. The activation energy differences between D-substitute and non-substituted methane, ethane, and propane are 318.6, 281.7, and 280.2cal/mol, respectively. In order to determine the effect of the entropy contribution for hydrogen isotopic substitution, a transition state for ethane bond rupture was determined based on density function theory (DFT) calculations. The kinetic isotope effect (KIE) associated with bond rupture in D and H substituted ethane results in a frequency factor ratio of 1.07. Based on the proposed mathematical model of hydrogen isotope fractionation, one can potentially quantify natural gas thermal maturity from measured hydrogen isotope values. Calculated gas maturity values determined by the proposed mathematical model using ??D values in ethane from several basins in the world are in close agreement with similar predictions based on the ??13C composition of ethane. However, gas maturity values calculated from field data of methane and propane using both hydrogen and carbon kinetic isotopic models do not agree as closely. It is possible that ??D values in methane may be affected by microbial mixing and that propane values might be more susceptible to hydrogen exchange with water or to analytical errors. Although the model used in this study is quite preliminary, the results demonstrate that kinetic isotope fractionation effects in hydrogen may be useful in quantitative models of natural gas generation, and that ??D values in ethane might be more suitable for modeling than comparable values in methane and propane. ?? 2011 Elsevier Ltd.

  7. Fundamental studies on kinetic isotope effect (KIE) of hydrogen isotope fractionation in natural gas systems

    NASA Astrophysics Data System (ADS)

    Ni, Yunyan; Ma, Qisheng; Ellis, Geoffrey S.; Dai, Jinxing; Katz, Barry; Zhang, Shuichang; Tang, Yongchun

    2011-05-01

    Based on quantum chemistry calculations for normal octane homolytic cracking, a kinetic hydrogen isotope fractionation model for methane, ethane, and propane formation is proposed. The activation energy differences between D-substitute and non-substituted methane, ethane, and propane are 318.6, 281.7, and 280.2 cal/mol, respectively. In order to determine the effect of the entropy contribution for hydrogen isotopic substitution, a transition state for ethane bond rupture was determined based on density function theory (DFT) calculations. The kinetic isotope effect (KIE) associated with bond rupture in D and H substituted ethane results in a frequency factor ratio of 1.07. Based on the proposed mathematical model of hydrogen isotope fractionation, one can potentially quantify natural gas thermal maturity from measured hydrogen