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Sample records for accurate sr isotope

  1. Development of an on-line flow injection Sr/matrix separation method for accurate, high-throughput determination of Sr isotope ratios by multiple collector-inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Galler, Patrick; Limbeck, Andreas; Boulyga, Sergei F; Stingeder, Gerhard; Hirata, Takafumi; Prohaska, Thomas

    2007-07-01

    This work introduces a newly developed on-line flow injection (FI) Sr/Rb separation method as an alternative to the common, manual Sr/matrix batch separation procedure, since total analysis time is often limited by sample preparation despite the fast rate of data acquisition possible by inductively coupled plasma-mass spectrometers (ICPMS). Separation columns containing approximately 100 muL of Sr-specific resin were used for on-line FI Sr/matrix separation with subsequent determination of (87)Sr/(86)Sr isotope ratios by multiple collector ICPMS. The occurrence of memory effects exhibited by the Sr-specific resin, a major restriction to the repetitive use of this costly material, could successfully be overcome. The method was fully validated by means of certified reference materials. A set of two biological and six geological Sr- and Rb-bearing samples was successfully characterized for its (87)Sr/(86)Sr isotope ratios with precisions of 0.01-0.04% 2 RSD (n = 5-10). Based on our measurements we suggest (87)Sr/(86)Sr isotope ratios of 0.713 15 +/- 0.000 16 (2 SD) and 0.709 31 +/- 0.000 06 (2 SD) for the NIST SRM 1400 bone ash and the NIST SRM 1486 bone meal, respectively. Measured (87)Sr/(86)Sr isotope ratios for five basalt samples are in excellent agreement with published data with deviations from the published value ranging from 0 to 0.03%. A mica sample with a Rb/Sr ratio of approximately 1 was successfully characterized for its (87)Sr/(86)Sr isotope signature to be 0.718 24 +/- 0.000 29 (2 SD) by the proposed method. Synthetic samples with Rb/Sr ratios of up to 10/1 could successfully be measured without significant interferences on mass 87, which would otherwise bias the accuracy and uncertainty of the obtained data.

  2. Sr isotopic tracer study of the Samail ophiolite, Oman

    International Nuclear Information System (INIS)

    Lanphere, M.A.; Coleman, R.G.; Hopson, C.A.

    1981-01-01

    We have measured Rb and Sr concentrations and Sr isotopic compositions in 41 whole-rock samples and 12 mineral separates from units of the Samail ophiolite, including peridotite, gabbro, plagiogranite diabase dikes, and gabbro and websterite dikes within the metamorphic peridotite. Ten samples of cummulate gabbro from the Wadir Kadir section and nine samples from the Wadi Khafifah section have mean 87 Sr/ 86 Sr ratios and standard deviations of 0.70314 +- 0.00030 and 0.70306 +- 0.00034, respectively. The dispersion in Sr isotopic composition may reflect real heterogeneities in the magma source region. The average Sr isotopic composition of cumulate gabbro falls in the range of isotopic compositions of modern midocean ridge basalt. The 87 Sr/ 86 Sr ratios of noncumulate gabbro, plagiogranite, and diabase dikes range from 0.7034 to 0.7047, 0.7038 to 0.7046, and 0.7037 to 0.7061, respectively. These higher 87 Sr/ 86 Sr ratios are due to alteration of initial magmatic compositions by hydrothermal exchange with seawater. Mineral separates from dikes that cut harzburgite tectonite have Sr isotopic compositions which agree with that of cumulate gabbro. These data indicate that the cumulate gabbro and the different dikes were derived from partial melting of source regions that had similar long-term histories and chemical compositions

  3. 87Sr/86Sr isotope fingerprinting of Scottish and Icelandic migratory shorebirds

    International Nuclear Information System (INIS)

    Evans, Jane; Bullman, Rhys

    2009-01-01

    Biosphere Sr isotope composition data from Iceland and Scotland suggest that terrestrially feeding birds from these two countries will have significantly different 87 Sr/ 86 Sr isotope composition in their tissues. The aim of this study is to test if these differences can be measured within the bone and feather of migratory wading birds, who feed terrestrially as juveniles, thus providing a provenance tool for these birds. The study shows that birds can be distinguished on the basis of the Sr isotope composition of their bone. The field for Icelandic birds is defined by data from juvenile common redshank (Tringa totanus) and whimbrel (Numenius phaeopus) which give 0.7056 ± 0.0012, (2σ, n = 7). The majority of Scottish birds in this study are from coastal regions and have a signature close to that of seawater of 0.7095 ± 0.0006 (2σ, n = 9). The Sr ratios in the body tissue of these two populations of all Icelandic and Scottish adult and juvenile birds analysed are significantly different (p 87 Sr/ 86 Sr values as high as 0.7194 which reflect their non-marine diet. Icelandic redshank (Tringa totanus robusta) that have flown to Scotland and returned to Iceland show the effect of the Scottish contribution to their diet with elevated values of 0.7086 ± 0.0004, (2σ, n = 6). Redshank found in Scotland that cannot be classified on the basis biometric analysis are shown to be of Icelandic origin and analysis of the primary feathers from two birds demonstrates that isotope variation between feathers could be used to track changes in diet related to the timing of individual feather growth.

  4. C, Sr and Sr isotopic composition on probable vendian- tommotian carbonate sequences in Nw Argentina

    International Nuclear Information System (INIS)

    Sial, A. N.; Ferreira, V.P; Toselli, A.J.; Acenolaza, F.G; Pimentel, M.M; Parada, M.A; Alonso, R.N

    2001-01-01

    C-isotope stratigraphy is one of the most powerfool tools in Precambrian chronostratigraphy, especially when sediments lack recognizable animal fossils. The δ 13 C secular variation curves for marine carbonates in the Neoproterozoic-Cambrian interval show strong positive-negative excursions, several of them interpreted as the stratigraphic position of ancient ice ages (Hoffman et al. 1998). The Sr isotope composition of the seawater for this age interval is characterized by a continuous increase of 87 Sr/ 86 Sr that is interrupted, several times, by sharp rises, which represent important changes in the Earth history (Montanez et al. 2000). Only limited data on the behavior of C and Sr isotopes in carbonates are available in South America. We examine here carbonate sequences from the Argentine Precordillera, San Juan province, and from other carbonate sequences in NW Argentina that could be, potentially, proxies for the Precambrian-Cambrian transition. We have studied their δ 13 C and 87 Sr/ 86 Sr chemostratigraphy and compare it to global C and Sr isotope secular variation curves for this time span. This study aims to improve the relatively coarse stratigraphic resolution provided only by the study of the fossil record in some of the carbonate successions under consideration (au)

  5. A new method of accurate determination of isotopic composition and concentration of strontium in a spike solution used for geochronological works

    International Nuclear Information System (INIS)

    Yanagi, Takeru

    1990-01-01

    A new method of accurate determination of isotopic composition and concentration of a strontium-84 spike solution was devised for simultaneous determination of strontium contents and isotopic compositions in rocks and minerals by measuring strontium isotopic ratios in spiked samples. In this method, the isotopic composition of strontium in the spike were determined so as to minimize the sum of squares of deviations of spike strontium-84 concentrations which were calculated from measured isotopic ratios of strontium in five different mixtures of the spike and the standard solution. The method can eliminate all mass discriminations occurred during the measurements on a surface ionization mass spectrometer. The results were tested by measuring 87 Sr/ 86 Sr ratios of Eimer and Amend SrCO 3 and JB-1 geochemical reference material, and by determining the strontium content in JB-1. The measurements of strontium isotope ratios in spiked samples give average values of 0.708007±0.000052 and 0.70417±0.00004 for 87 Sr/ 86 Sr ratios of E and A SrCO 3 and JB-1, respectively. The strontium content in JB-1 was estimated at 457.1±1.3 ppm. These values are very close to reported respective values. (author)

  6. Vadose Zone Infiltration Rates from Sr isotope Measurements

    Science.gov (United States)

    Maher, K.; Maher, K.; DePaolo, D. J.; DePaolo, D. J.; Conrad, M.

    2001-12-01

    Predicting infiltration rates and recharge through the vadose zone in arid regions is difficult and hence developing methods for the measurement of infiltration rates is important. We have been investigating the use of Sr isotope measurements for determining infiltration at the 200 Area plateau on the Hanford reservation in central Washington. In this context, infiltration affects the transport of contaminants to the water table as well as recharge of the groundwater system. Using Sr isotopes for this purpose requires drill core and water samples from the vadose zone, although leaches of the cores can substitute for water samples. Complementary information, including some constraints on regional recharge, can also be obtained using water samples from groundwater monitoring wells. The VZ method is based on the fact that the Sr isotope ratio of soil water just below the surface is often set by dissolution of aeolian material including carbonate, and this ratio is different from the average value in the deeper underlying vadose zone rock matrix. As water infiltrates, the Sr isotopic composition of the water changes toward the rock values as a result of Sr released from the rocks by weathering reactions. The rate of change with depth of the Sr isotope ratio of the vadose zone water is a function ultimately of q/R; the ratio of the infiltration flux (q) to the bulk rock weathering rate (R). Where it is possible to evaluate R, q can be estimated. As data accumulate it may be possible to improve the calibration of the method. At Hanford the vadose zone rock material is mostly unconsolidated sand, silt, and gravel of broadly granitic composition, which constitute the Hanford and Ringold formations. Annual precipitation is about 160 mm/yr. Drilling and coring of a ca. 70m hole to the water table in 1999 as part of the Hanford groundwater monitoring program, in a relatively undisturbed area of the site, allowed us to generate a unique Sr isotope data set. The Sr isotope

  7. Strontium isotope fractionation during strontianite (SrCO3) dissolution, precipitation and at equilibrium

    Science.gov (United States)

    Mavromatis, Vasileios; Harrison, Anna L.; Eisenhauer, Anton; Dietzel, Martin

    2017-12-01

    In this study we examine the behavior of stable Sr isotopes between strontianite [SrCO3] and reactive fluid during mineral dissolution, precipitation, and at chemical equilibrium. Experiments were performed in batch reactors at 25 °C in 0.01 M NaCl solutions wherein the pH was adjusted by bubbling of a water saturated gas phase of pure CO2 or atmospheric air. The equilibrium Sr isotope fractionation between strontianite and fluid after dissolution of the solid under 1 atm CO2 atmosphere was estimated as Δ88/86SrSrCO3-fluid = δ88/86Sr SrCO3 - δ88/86Srfluid = -0.05 ± 0.01‰. On the other hand, during strontianite precipitation, an enrichment of the fluid phase in 88Sr, the heavy isotopomer, was observed. The evolution of the δ88/86Srfluid during strontianite precipitation can be modeled using a Rayleigh distillation approach and the estimated, kinetically driven, fractionation factor αSrCO3-fluid between solid and fluid is calculated to be 0.99985 ± 0.00003 corresponding to Δ88/86SrSrCO3-fluid = -0.15‰. The obtained results further support that under chemical equilibrium conditions between solid and fluid a continuous exchange of isotopes occurs until the system approaches isotopic equilibrium. This isotopic exchange is not limited to the outer surface layer of the strontianite crystal, but extends to ∼7-8 unit cells below the crystal surface. The behavior of Sr isotopes in this study is in excellent agreement with the concept of dynamic equilibrium and it suggests that the time needed for achievement of chemical equilibrium is generally shorter compared to that for isotopic equilibrium. Thus it is suggested that in natural Sr-bearing carbonates an isotopic change may still occur close to thermodynamic equilibrium, despite no observable change in aqueous elemental concentrations. As such, a secondary and ongoing change of Sr isotope signals in carbonate minerals caused by isotopic re-equilibration with fluids has to be considered in order to use Sr

  8. Sr - an element shows the way - Applications of Sr isotopes for provenance, tracing and migration (Invited)

    Science.gov (United States)

    Prohaska, T.; Irrgeher, J.; Zitek, A.; Teschler Nicola, M.

    2010-12-01

    Strontium - named after the small Scottish town Strontian - as such is an element with little popularity. Firstly described by Martin Heinrich Klaproth in 1798, the metal is used in metallurgy to some extent whereas its compounds are interesting in glass industries, electronics and pyrotechnics. The element has chemical similarity to Ca and makes up 1/60 of the earth’s amount of the latter. Nonetheless, it is its isotopic composition which makes Sr so interesting for a large number of scientists. The natural composition of the four naturally occurring isotopes (84Sr, 86Sr 87Sr and 88Sr) varies in nature due to the radioactive decay of 87Rb to 87Sr. Thus, it was early recognized as geochronometer especially in Ca rich matrices. With increasing precision of applied methodology, the natural variation of the 87Sr/86Sr isotope ratio (analyzed at first mainly by thermal ionization mass spectrometry (TIMS)) became more and more popular in provenance studies. The natural variation of the ratio is mainly determined by the geological age and the original composition of the rock and can be used therefore as fingerprint of the local geology. The ratio is transferred with no significant fractionation via the water into plants and finally via the food chain into animal and human tissues (especially bones and teeth). As the element is chemically similar to Ca, it appears in most matrices. The use for provenance studies is supported by the fact that the long half life (4.8 x 1010 years) does not lead to an alteration during the time scales which are investigated (from recent samples to human or animal skeletal remains which date back up to 30.000 BC). The uniqueness of the system besides the natural variation is defined by the ubiquity in nature and the relatively high (and thus measurable) elemental concentration in most tissues. It was finally the advent of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) which augmented the number of applications

  9. An analytical approach to Sr isotope ratio determination in Lambrusco wines for geographical traceability purposes.

    Science.gov (United States)

    Durante, Caterina; Baschieri, Carlo; Bertacchini, Lucia; Bertelli, Davide; Cocchi, Marina; Marchetti, Andrea; Manzini, Daniela; Papotti, Giulia; Sighinolfi, Simona

    2015-04-15

    Geographical origin and authenticity of food are topics of interest for both consumers and producers. Among the different indicators used for traceability studies, (87)Sr/(86)Sr isotopic ratio has provided excellent results. In this study, two analytical approaches for wine sample pre-treatment, microwave and low temperature mineralisation, were investigated to develop accurate and precise analytical method for (87)Sr/(86)Sr determination. The two procedures led to comparable results (paired t-test, with tisotopic values were compared with isotopic data coming from (i) soils of their territory of origin and (ii) wines obtained by same grape varieties cultivated in different districts. The obtained results have shown no significant variability among the different vintages of wines and a perfect agreement between the isotopic range of the soils and wines has been observed. Nevertheless, the investigated indicator was not enough powerful to discriminate between similar products. To this regard, it is worth to note that more soil samples as well as wines coming from different districts will be considered to obtain more trustworthy results. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Potential of Sr isotopic analysis in ceramic provenance studies: Characterisation of Chinese stonewares

    Science.gov (United States)

    Li, Bao-Ping; Zhao, Jian-Xin; Greig, Alan; Collerson, Kenneth D.; Zhuo, Zhen-Xi; Feng, Yue-Xin

    2005-11-01

    We compare the trace element and Sr isotopic compositions of stoneware bodies made in Yaozhou and Jizhou to characterise these Chinese archaeological ceramics and examine the potential of Sr isotopes in provenance studies. Element concentrations determined by ICP-MS achieve distinct characterisation for Jizhou samples due to their restricted variation, yet had limited success with Yaozhou wares because of their large variability. In contrast, 87Sr/86Sr ratios in Yaozhou samples have a very small variation and are all significantly lower than those of Jizhou samples, which show a large variation and cannot be well characterised with Sr isotopes. Geochemical interpretation reveals that 87Sr/86Sr ratios will have greater potential to characterise ceramics made of low Rb/Sr materials such as kaolin clay, yet will show larger variations in ceramics made of high Rb/Sr materials such as porcelain stone.

  11. Potential of Sr isotopic analysis in ceramic provenance studies: Characterisation of Chinese stonewares

    International Nuclear Information System (INIS)

    Li Baoping; Zhao Jianxin; Greig, Alan; Collerson, Kenneth D.; Zhuo Zhenxi; Feng Yuexin

    2005-01-01

    We compare the trace element and Sr isotopic compositions of stoneware bodies made in Yaozhou and Jizhou to characterise these Chinese archaeological ceramics and examine the potential of Sr isotopes in provenance studies. Element concentrations determined by ICP-MS achieve distinct characterisation for Jizhou samples due to their restricted variation, yet had limited success with Yaozhou wares because of their large variability. In contrast, 87 Sr/ 86 Sr ratios in Yaozhou samples have a very small variation and are all significantly lower than those of Jizhou samples, which show a large variation and cannot be well characterised with Sr isotopes. Geochemical interpretation reveals that 87 Sr/ 86 Sr ratios will have greater potential to characterise ceramics made of low Rb/Sr materials such as kaolin clay, yet will show larger variations in ceramics made of high Rb/Sr materials such as porcelain stone

  12. Tracing subduction zone fluid-rock interactions using trace element and Mg-Sr-Nd isotopes

    Science.gov (United States)

    Wang, Shui-Jiong; Teng, Fang-Zhen; Li, Shu-Guang; Zhang, Li-Fei; Du, Jin-Xue; He, Yong-Sheng; Niu, Yaoling

    2017-10-01

    Slab-derived fluids play a key role in mass transfer and elemental/isotopic exchanges in subduction zones. The exhumation of deeply subducted crust is achieved via a subduction channel where fluids from various sources are abundant, and thus the chemical/isotopic compositions of these rocks could have been modified by subduction-zone fluid-rock interactions. Here, we investigate the Mg isotopic systematics of eclogites from southwestern Tianshan, in conjunction with major/trace element and Sr-Nd isotopes, to characterize the source and nature of fluids and to decipher how fluid-rock interactions in subduction channel might influence the Mg isotopic systematics of exhumed eclogites. The eclogites have high LILEs (especially Ba) and Pb, high initial 87Sr/86Sr (up to 0.7117; higher than that of coeval seawater), and varying Ni and Co (mostly lower than those of oceanic basalts), suggesting that these eclogites have interacted with metamorphic fluids mainly released from subducted sediments, with minor contributions from altered oceanic crust or altered abyssal peridotites. The positive correlation between 87Sr/86Sr and Pb* (an index of Pb enrichment; Pb* = 2*PbN/[CeN + PrN]), and the decoupling relationships and bidirectional patterns in 87Sr/86Sr-Rb/Sr, Pb*-Rb/Sr and Pb*-Ba/Pb spaces imply the presence of two compositionally different components for the fluids: one enriched in LILEs, and the other enriched in Pb and 87Sr/86Sr. The systematically heavier Mg isotopic compositions (δ26Mg = - 0.37 to + 0.26) relative to oceanic basalts (- 0.25 ± 0.07) and the roughly negative correlation of δ26Mg with MgO for the southwestern Tianshan eclogites, cannot be explained by inheritance of Mg isotopic signatures from ancient seafloor alteration or prograde metamorphism. Instead, the signatures are most likely produced by fluid-rock interactions during the exhumation of eclogites. The high Rb/Sr and Ba/Pb but low Pb* eclogites generally have high bulk-rock δ26Mg values

  13. Potential of Sr isotopic analysis in ceramic provenance studies: Characterisation of Chinese stonewares

    Energy Technology Data Exchange (ETDEWEB)

    Li Baoping [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia)]. E-mail: b.li@uq.edu.au; Zhao Jianxin [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia); Greig, Alan [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia); Collerson, Kenneth D. [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia); Zhuo Zhenxi [Shaanxi Provincial Institute of Archaeology, Xi' an 710054 (China); Feng Yuexin [Advanced Centre for Queensland University Isotope Research Excellence (ACQUIRE), University of Queensland, Brisbane, Qld 4072 (Australia)

    2005-11-15

    We compare the trace element and Sr isotopic compositions of stoneware bodies made in Yaozhou and Jizhou to characterise these Chinese archaeological ceramics and examine the potential of Sr isotopes in provenance studies. Element concentrations determined by ICP-MS achieve distinct characterisation for Jizhou samples due to their restricted variation, yet had limited success with Yaozhou wares because of their large variability. In contrast, {sup 87}Sr/{sup 86}Sr ratios in Yaozhou samples have a very small variation and are all significantly lower than those of Jizhou samples, which show a large variation and cannot be well characterised with Sr isotopes. Geochemical interpretation reveals that {sup 87}Sr/{sup 86}Sr ratios will have greater potential to characterise ceramics made of low Rb/Sr materials such as kaolin clay, yet will show larger variations in ceramics made of high Rb/Sr materials such as porcelain stone.

  14. Transgenerational isotopic marking of carp Cyprinus carpio, L. using a 86Sr /84Sr double spike

    Science.gov (United States)

    Zitek, Andreas; Cervicek, Magdalena; Irrgeher, Johanna; Horsky, Monika; Kletzl, Manfred; Weismann, Thomas; Prohaska, Thomas

    2013-04-01

    Transgenerational isotopic marking has been recognized recently as an effective tool for mass marking and tracking of individual fish to their original source. Compared to other conventional marking techniques, transgenerational marking offers several advantages. Most importantly, it is possible to mark all offspring of one individual female without the necessity of handling eggs or larval fish. Furthermore it is possible to vary the concentrations of individual isotopes to obtain specific marks for individual female fish. An enriched isotopic spike solution is usually applied to gravid female spawners by injection into the body cavity for transgenerational marking. The isotope is then incorporated into the central otolith region of the offspring which is known to be built up by maternally derived material. Within this study transgenerational marking of a typical cyprinid fish species, Cyprinus carpio, L., was tested using a 86Sr /84Sr double spike. Buffered solutions with different isotopic composition and concentrations were administered to 4 female individuals by intraperitoneal injection 5 days before spawning, while one female was injected a blank solution. After spawning, otoliths (Lapilli) from juvenile fish were sampled at the age of about 5 months at fish sizes between 3 and 4 cm and analyzed for their isotopic composition by LA-ICPMS applying cross sectional line scans. Central otolith regions of the progeny showed a shift in the natural isotope ratios for the administered isotopes. Deconvolution of the blank corrected measurement data of the Sr isotopes was done to trace back the original spike ratio. The different spike ratios could be well distinguished reflecting the original composition of the spike solution. This study proved that it is possible to create batch-specific unique transgenerational marks in otolith cores by varying the concentrations of two naturally occurring Sr isotopes. This method has high potential to reduce the marking effort for

  15. Tracking selenium in the Chalk aquifer of northern France: Sr isotope constraints

    International Nuclear Information System (INIS)

    Cary, L.; Benabderraziq, H.; Elkhattabi, J.; Gourcy, L.; Parmentier, M.; Picot, J.; Khaska, M.; Laurent, A.; Négrel, Ph.

    2014-01-01

    Highlights: • We report the chemistry of the Chalk groundwater affected by Se contamination. • Strontium isotopes were used to identify the groundwater bodies and their mixings. • The spatial and temporal Se variability is mainly linked to the presence of Se-rich clays. • Saturation or desaturation of Se-rich clays control Se mobility. - Abstract: Groundwater at the southern and eastern edges of France’s Paris Basin has a selenium content that at times exceeds the European Framework Directive’s drinking-water limit value of 10 μg/L. To better understand the dynamics of the Chalk groundwater being tapped to supply the city of Lille and the Se origins, we used a combination of geochemical and isotopic tools. Strontium isotopes, coupled with Ca/Sr, Mg/Sr and Se/Sr ratios, were used to identify the main groundwater bodies and their mixings, with the Mg/Sr and Se/Sr ratios constraining a ternary system. Groundwater in the agricultural aquifer-recharge zone represents a first end-member and displays the youngest water ages of the catchment along with the highest Sr isotopic signature (0.70842) and low Se contents. Anaerobic groundwater constitutes a second major end-member affected by water-rock interactions over a long residence time, with the lowest Sr isotopic signature (0.70789) and the lowest Se content, its low SF6 content confirming the contribution of old water. Se-rich groundwater containing up to 30 μg/L of Se represents a third major end-member, with an intermediate Sr isotopic ratio (0.70826), and is mainly constrained by the clayey Se-rich formation overlying the Chalk aquifer. The spatial and temporal Se variability in the groundwater is clearly linked to the presence of this formation identified as Tertiary and also to the hydrological conditions; saturation of the Se-rich clays by oxygenated groundwater enhances Se mobility and also Sr adsorption onto the clays. This multi-tool study including Sr isotopes successfully identified the Se

  16. Comparison of the Sr isotopic signatures in brines of the Canadian and Fennoscandian shields

    International Nuclear Information System (INIS)

    Negrel, Philippe; Casanova, Joel

    2005-01-01

    A synthesis of Sr isotope data from shallow and deep groundwaters, and brines from the Fennoscandian and Canadian Shields is presented. A salinity gradient is evident in the water with concentrations varying from approximately 1-75 g L -1 below 1500 m depth in the Fennoscandian Shield and from 10 up to 300 g L -1 below 650 m depth in the Canadian Shield. Strontium isotope ratios were measured to assess the origin of the salinity and evaluate the degree of water-rock interaction in the systems. In both shields, the Sr concentrations are enriched relative to Cl, defining a positive trend parallel to the seawater dilution line and indicative of Sr addition through weathering processes. The depth distribution for Sr concentration increases strongly with increasing depth in both shields although the variation in Sr-isotope composition does not mirror that of Sr concentrations. Strontium-isotope compositions are presented for surface waters, and groundwaters in several sites in the Fennoscandian and Canadian Shields. Numerous mixing lines can be drawn reflecting water-rock interaction. A series of calculated lines links the surface end-members (surface water and shallow groundwater) and the deep brines; these mixing lines define a range of 87 Sr/ 86 Sr ratios for the deep brines in different selected sites. All sites show a specific 87 Sr/ 86 Sr signature and the occurrence of large 87 Sr/ 86 Sr variations is site specific in both shields. In Canadian Shield brines, the Sr isotope ratios clearly highlight large water rock interaction that increases the 87 Sr/ 86 Sr ratio from water that could have been of marine origin. In contrast to the Canadian Shield, groundwater does not occur in closed pockets in the Fennoscandian, and the well-constrained 87 Sr/ 86 Sr signatures in deep brines should correspond to a large, well-mixed and homogeneous water reservoir, whose Sr isotope signature results from water-rock interaction

  17. Isotope ratio 87Sr/86Sr in limestones from Bambui group, Brazil (MG)

    International Nuclear Information System (INIS)

    Kawashita, K.; Mizusaki, A.M.P.; Kiang, C.H.

    1987-01-01

    The Sr composition of ancient seawater can be estimated from the analysis of carbonate rocks and, in some cases, used to estimate the age of the analyzed carbonate. The normalized 87Sr/86Sr ratios in calcium carbonate fractions from 14 core samples in the Bambui Group near Montalvania, MG, were found to range between .7077 and .7280. The higher values are attributable to Sr isotopic exchange between silicate and carbonate phases during diagenesis. The ratio of .7077 obtained in two pure calcium carbonate samples is here suggested as the best aproximation for the 87Sr/86Sr value for the Bambui sea. This ratio is compatible with an age of about 700 Ma., estimated from the published 87Sr/86Sr curve of Veizer and others, an age in accordance with Quadros recent (1987, in preparation) identification of marine acritarchs from the latest Precambrian (Vendian). (author) [pt

  18. Pb and Sr isotopic compositions of ancient pottery: a method to discriminate production sites

    International Nuclear Information System (INIS)

    Zhang Xun; Chen Jiangfeng; Ma Lin; He Jianfeng; Wang Changsui; Qiu Ping

    2004-01-01

    The discriminating of production sites of ancient pottery samples using multi-isotopic systematics was described. Previous work has proven that Pb isotopic ratios can be used for discriminating the production sites of ancient pottery under certain conditions. The present work suggests that although Nd isotopic ratios are not sensitive to the production sites of ancient pottery, Sr isotopic ratios are important for the purpose. Pb isotopic ratios are indistinguishable for the pottery excavated from the Jiahu relict, Wuyang, Henan Province and for famous Qin Terra-cotta Figures. But, the 87 Sr/ 86 Sr ratios for the former (about 0.715) are significantly lower than that of the latter (0.717-0.718). The authors concluded that a combined use of Pb and Sr isotopes would be a more powerful method for discriminating the production site of ancient pottery. (authors)

  19. 87Sr/86Sr isotope ratio analysis by laser ablation MC-ICP-MS in scales, spines, and fin rays as a nonlethal alternative to otoliths for reconstructing fish life history

    Science.gov (United States)

    Willmes, Malte; Glessner, Justin J. G.; Carleton, Scott A.; Gerrity, Paul C.; Hobbs, James A.

    2016-01-01

    Strontium isotope ratios (87Sr/86Sr) in otoliths are a well-established tool to determine origins and movement patterns of fish. However, otolith extraction requires sacrificing fish, and when working with protected or endangered species, the use of nonlethal samples such as scales, spines, and fin rays is preferred. Unlike otoliths that are predominantly aragonite, these tissues are composed of biological apatite. Laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) analysis of biological apatite can induce significant interference on mass 87, causing inaccurate 87Sr/86Sr measurements. To quantify this interference, we applied LA-MC-ICP-MS to three marine samples (white seabass (Atractoscion nobilis) otolith; green sturgeon (Acipenser medirostris) pectoral fin ray; salmon shark (Lamna ditropis) tooth), and freshwater walleye (Sander vitreus) otoliths, scales, and spines). Instrument conditions that maximize signal intensity resulted in elevated 87Sr/86Sr isotope ratios in the bioapatite samples, related to a polyatomic interference (40Ca31P16O, 40Ar31P16O). Retuning instrument conditions to reduce oxide levels removed this interference, resulting in accurate 87Sr/86Sr ratios across all tissue samples. This method provides a novel, nonlethal alternative to otolith analysis to reconstruct fish life histories.

  20. The temperature dependent strontium isotope fractionation (δ88/86Sr) during calcium carbonate precipitation

    International Nuclear Information System (INIS)

    Fietzke, J.; Eisenhauer, A.

    2006-01-01

    Full text: In order to study the influence of stable isotope fractionation during inorganic and biologically controlled CaCO 3 precipitation we have developed the analytical principles for the measurement of strontium (Sr) isotope fractionation. We have established a measurement protocol for the application on a MC-ICP-MS (AXIOM) using the common bracketing standard technique. The Sr-standard CRM NBS987 was used as reference material for all measurements and to calculate the Sr fractionation. Latter value is expressed by the δ-notation defined as: δ 88/86 Sr = [( 88 Sr/ 86 Sr)sample / ( 88 Sr/ 86 Sr)standard ] * 1000 -1. A first set of experiments focused on the temperature dependency of Sr-isotope fractionation. For this purpose inorganically precipitated aragonite and calcite was prepared under controlled conditions in a temperature range from 10 to 50 o C. In addition, cultured and naturally grown corals were analyzed for their δ 88/86 Sr values. Repeated measurements of IAPSO seawater standard showed a mean δ 88/86 Sr value of 0.383 ± 0.008 (2 SEM) being the isotopically heaviest material measured so far. The first results of the inorganically precipitated aragonite and the natural corals revealed a clear temperature dependency of the δ 88/86 Sr values. For inorganic aragonite the slope of this correlation is about 0.0055 permil/ o C. However, for naturally grown corals (Pavona clavus) a 6 fold steeper slope of 0.033 permil/ o C was determined. This strong temperature dependency implies the potential to use stable Sr isotopes as a new marine (paleo)temperature proxy. (author)

  1. Study on Sr-Nd isotopes of mesozoic-cenozoic granites in Qinghai-Tibetan plateau

    International Nuclear Information System (INIS)

    Qiu Ruizhao; Deng Jinfu; Zhou Su; Xiao Qinghui; Cai Zhiyong

    2003-01-01

    Mesozoic-Cenozoic magmatic activities were intensive in Qinghai-Tibetan plateau. Nd-Sr isotopic compositions of representative granitic plutons in western Qinghai-Tibetan plateau are reported in this paper. Combining with past isotopic data, which has reported in eastern Qinghai-Tibetan plateau, Sr-Nd isotopic compositions and material source and genesis of Mesozoic and Cenozoic granites in Qinghai-Tibetan plateau have been studied. The research result indicates there are three types of granite existing in Qinghai-Tibetan plateau, the granites of Late stage of Yanshan Period which distributing on north and south boundary of Gandes block (namely in north and south granitic belts of Dangdes) and cause of oceanic crust subduction, have ( 87 Sr/ 86 Sr)i of 0.7041-0.7064, ε (Nd) t of +2.5 - +5.7 and TDM age of 312-562 Ma, positive ε Nd, low ( 87 Sr/ 86 Sr)i ratio and young Nd model ages suggest relatively high contents of mantle-derived components in their sources, and this type granite might melt from subduction oceanic crust. The granites occurred intra-Gangdes block which were caused by collision of continent and post-collision, have ( 87 Sr/ 86 Sr)i of 0.706-0.719, ε (Nd) t of -5.3 - -8.3 and TDM age of 1323-1496 Ma, negative ε Nd, relative high ( 87 Sr/ 86 Sr)i ratio with an mid-Proterozoic Nd model ages, suggest granite has the mixing genesis of mantle-derived components and old crustal components in their sources. With relatively small variation range in ε (Nd) t and TDM age, it might imply granitic isotopic source in Gandes block to keep relative homogenization in long period. The granites in Himalayan block which there is not oceanic material to join in melting and to cause of intra-continental subduction, has most ( 87 Sr/ 86 Sr)i ratio more than 0.720, ε (Nd) t of -10.3 - -16.3 and TDM age of 1792-2206 Ma, high ( 87 Sr/ 86 Sr)i ratio, low negative ε (Nd)t with old Nd isotopic model ages and consistent with the Sr, Nd isotopic compositions of basement

  2. Observation of Isotope Ratios (δ2H, δ18O, 87Sr/86Sr) of Tap Water in Urban Environments

    Science.gov (United States)

    Mancuso, C. J.; Tipple, B. J.; Ehleringer, J. R.

    2014-12-01

    Urban environments are centers for rapidly growing populations. In order to meet the culinary water needs of these areas, municipal water departments use water from multiple locations and/or sources, often piped differentially to different locations within a municipality. This practice creates isotopically distinct locations within an urban area and therefore provides insight to urban water management practices. In our study we selected urban locations in the Salt Lake Valley, UT (SLV) and San Francisco Bay Area, CA (SFB) where we hypothesized geographically distinct water isotopic ratio differences existed. Within the SLV, municipal waters come from the same mountainous region, but are derived from different geologically distinct watersheds. In contrast, SFB waters are derived from regionally distinct water sources. We hypothesized that the isotope ratios of tap waters would differ based upon known municipal sources. To test this, tap water samples were collected throughout the urban regions in SLV and SFB and analyzed for δ2H, δ18O and 87Sr/86Sr isotope ratios. Seasonal collections were also made to assess if isotope ratios differed throughout the year. Within SLV and SFB, different regions were characterized by distinct paired δ18O and 87Sr/86Sr values. These different realms also agreed with known differences in municipal water supplies within the general geographic region. Waters from different cities within Marin County showed isotopic differences, consistent with water derived from different local reservoirs. Seasonal variation was observed in paired δ18O and 87Sr/86Sr values of tap water for some locations within SLV and SFB, indicating management decisions to shift from one water source to another depending on demand and available resources. Our study revealed that the δ18O and 87Sr/86Sr values of tap waters in an urban region can exhibit significant differences despite close spatial proximity if districts differ in their use of local versus

  3. Sr isotopes and U series radionuclides in the Sangemini area (Central Italy: Hydrogeology implications

    Directory of Open Access Journals (Sweden)

    Maurizio Barbieri

    2014-06-01

    Full Text Available The strontium isotopic ratio (expressed as 87Sr/86Sr of groundwater represents a useful method for studying and understanding the groundwater circulations, also, the U and Ra isotopic compositions can vary as function of the groundwater residence time. This paper reports an evaluation of the probable recharge area of the Sangemini mineral water springs (Terni-Umbria Central Italy and an estimate of the residence time of the aquifer by coupling Sr and U series isotopic systematics. For this study have been analyzed four water sample for the isotope ratio of 87Sr/86Sr, and eleven samples, shallow waters and groundwaters, for U and Ra, furthermore were determined the values of isotopic ratio for sample of typical rocks of the area. The results of this study allow to identify: a recharge area in a restricted sector of the Meso-Cenozoic carbonates a longer and more effective water/rock interaction in the Quaternary series. U and Ra recoil models allow to estimate a groundwater residence time of about 350 years and a total water volume whose value (64*106 m3 agrees with the limited extension of the aquifer. The extension of the aquifer was constrained by comparing Sr isotopic composition of waters and local geological formations. Groundwaters seem mainly to circulate in clayey sandy Quaternary series characterized by low redox conditions.

  4. Sr-Nd-Hf isotopic fingerprinting of transatlantic dust derived from North Africa

    Science.gov (United States)

    Zhao, Wancang; Balsam, William; Williams, Earle; Long, Xiaoyong; Ji, Junfeng

    2018-03-01

    Long-range transport of African dust plays an important role in understanding dust-climate relationships including dust source areas, dust pathways and associated atmospheric and/or oceanic processes. Clay-sized Sr-Nd-Hf isotopic compositions can be used as geochemical fingerprints to constrain dust provenance and the pathways of long-range transported mineral dust. We investigated the clay-sized Sr-Nd-Hf isotopic composition of surface samples along four transects bordering the Sahara Desert. The transects are from Mali, Niger/Benin/Togo, Egypt and Morocco. Our results show that the Mali transect on the West African Craton (WAC) produces lower εNd (εNd-mean = -16.38) and εHf (εHf-mean = -9.59) values than the other three transects. The Egyptian transect exhibits the lowest 87Sr/86Sr ratios (87Sr/86Srmean = 0.709842), the highest εHf (εHf-mean = -0.34) and εNd values of the four transects. Comparison of the clay-sized Sr-Nd-Hf isotopic values from our North African samples to transatlantic African dust collected in Barbados demonstrates that the dust's provenance is primarily the western Sahel and Sahara as well as the central Sahel. Summer emission dust is derived mainly from the western Sahel and Sahara regions. The source of transatlantic dust in spring and autumn is more varied than in the summer and includes dust not only from western areas, but also south central areas. Comparison of the Sr-Nd-Hf isotopic fingerprints between the source and sink of transatlantic dust also suggests that a northwestward shift in dust source occurs from the winter, through the spring and into the summer. The isotopic data we develop here provide another tool for discriminating changes in dust archives resulting from paleoenvironmental evolution of source regions.

  5. 44/40Ca and 87Sr/86Sr isotopes as tracers of silicate weathering in small catchments of the Massif Central, France

    Science.gov (United States)

    Négrel, Philippe; Guerrot, Catherine; Millot, Romain; Petelet-Giraud, Emmanuelle; Bullen, Thomas

    2013-04-01

    We present calcium stable isotope and strontium radiogenic isotope data for soils and sediments developed on volcanic and igneous rocks forming small catchments in the Massif Central (France). Measurements of 44/40Ca isotope ratios (44/40Ca measured by the double spike method on TIMS and normalized to the value for seawater Ca in delta units) in rocks, sediments and soils from silicate catchments (e.g. granite and basalts) together with 87Sr/86Sr isotope ratios permit an examination of the relationships of these isotope systematics during weathering of silicate rocks. We have analysed the granite, weathered granite (arene) and saprolite, sediment and soil overlying the granite on one hand and the basanite, sediment and soil overlying the basanite on the other. The main bedrock in the volcanic zone (e.g. Allanche catchment) is 11 to 2.5 Ma basanite (nephelinitic to leucitic basalts) having SiO2 between 41-45 wt. %, Na2O + K2O bank have 87Sr/86Sr ratios greater than that of the arene with values increasing in the sediment from the surface down to soil. The 87Sr/86Sr vs. Rb/Sr variation observed in the volcanic area likewise confirms the weathering of low 87Sr/86Sr, low Rb/Sr phases in the bedrock, and there is a linear increase in 87Sr/86Sr and Rb/Sr ratios from those in the sediment up to the values observed in the soils. In the volcanic area, the basanite bedrock has 44/40Ca = -0.94 ± 0.05‰ (n = 7), while the soils and sediments have 44/40Ca of -0.75 to -1.13‰ and -0.79 to -1.01‰, respectively. These results suggest that Ca isotopes are not strongly fractionated during weathering of the basalt. The granite whole-rock has 44/40Ca of -1.29‰, while the soil and sediments have 44/40Ca of -1.93 to -2.07‰ and -1.98 to -2.81‰, respectively, with values decreasing as the Ca content decreases. The 44/40Ca ratios of arene, soil and sediment are similar to or less than that of K- feldspar, reflecting complete loss of the relatively heavy Ca from plagioclase and

  6. New aragonite 87Sr/86Sr records of Mesozoic ammonoids and approach to the problem of N, O, C and Sr isotope cycles in the evolution of the Earth

    Science.gov (United States)

    Zakharov, Yuri D.; Dril, Sergei I.; Shigeta, Yasunari; Popov, Alexander M.; Baraboshkin, Eugenij Y.; Michailova, Irina A.; Safronov, Peter P.

    2018-02-01

    New Sr isotope data from well-preserved aragonite ammonoid shell material from the Mesozoic are compared with that from a living Nautilus shell. The prominent negative Sr isotope excursions known from the Middle Permian, Jurassic and Cretaceous probably have their origins in intensive plate tectonic activity, followed by enhanced hydrothermal activity at the mid-ocean ridges (mantle volcanism) which supplied low radiogenic Sr to seawater. The maximum positive (radiogenic) shift in the lower Mesozoic Sr isotope curve (Lower Triassic peak) was likely caused by a significant expansion of dry land surfaces (Dabie-Sulu Triassic orogeny) and their intensive silicate weathering in conditions of extreme warming and aridity in the very end of the Smithian, followed by warm and humid conditions in the late Spathian, which apparently resulted in a significant oceanic input of radiogenic Sr through riverine flux. The comparatively high 87Sr/86Sr ratio obtained from the living Nautilus shell is probably a function of both the Alpine orogeny, which was accompanied by significant continental weathering and input of radiogenic Sr to the oceans, and the weakening of mantle volcanism.

  7. 87Sr/86Sr isotopes in grapes of different cultivars: A geochemical tool for geographic traceability of agriculture products.

    Science.gov (United States)

    Tescione, Ines; Marchionni, Sara; Casalini, Martina; Vignozzi, Nadia; Mattei, Massimo; Conticelli, Sandro

    2018-08-30

    87 Sr/ 86 Sr was determined on fresh red and white grapes, soils and rocks from three selected vineyards to verify the isotopic relationships between the fruit of the vine and geologic substrata of vineyards. 87 Sr/ 86 Sr were determined on sampled grapes of four different harvest years and different grape varieties, on bioavailable fraction of soils, on whole soils, and on bedrocks from the geo-pedological substratum of the vineyards. The vineyards chosen for the experimental works belong to an organic farming winery and thus cultivation procedures were strictly controlled. Grapes were sampled during the harvests of four different but consecutive years with 87 Sr/ 86 Sr that does not change reflecting the values of the soil bioavailable fraction. No variations among grapes from different vine cultivars were observed. A strict isotope relationship with soil bio-available fraction was observed. These findings demonstrate the reliability of 87 Sr/ 86 Sr, even at a very small scale, for food products geographic origin assessment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Identification of Marchfeld asparagus using Sr isotope ratio measurements by MC-ICP-MS.

    Science.gov (United States)

    Swoboda, S; Brunner, M; Boulyga, S F; Galler, P; Horacek, M; Prohaska, T

    2008-01-01

    This work focuses on testing and application of Sr isotope signatures for the fast and reliable authentication and traceability of Asparagus officinalis originating from Marchfeld, Austria, using multicollector inductively coupled plasma mass spectrometry after optimised Rb/Sr separation. The major sample pool comprises freeze-dried and microwave-digested asparagus samples from Hungary and Slovakia which are compared with Austrian asparagus originating from the Marchfeld region, which is a protected geographical indication. Additional samples from Peru, The Netherlands and Germany were limited in number and allowed therefore only restricted statistical evaluation. Asparagus samples from Marchfeld were harvested within two subsequent years in order to investigate the annual variation. The results show that the Sr isotope ratio is consistent within these 2 years of investigation. Moreover, the Sr isotope ratio of total Sr in soil was found to be significantly higher than in an NH4NO3 extract, reflecting the mobile (bioavailable) phase. The isotope composition in the latter extract corresponds well to the range found in the asparagus samples in Marchfeld, even though the concentration of Sr in asparagus shows no direct correlation to the concentration of Sr in the mobile phase of the soil. The major question was whether the 'Marchfelder Spargel' can be distinguished from samples from the neighbouring countries of Hungary and Slovakia. According to our findings, they can be clearly (100%) singled out from the Hungarian samples and can be distinguished from the Slovakian asparagus samples with a probability of more than 80%.

  9. Geothermal waters from the Taupo Volcanic Zone, New Zealand: Li, B and Sr isotopes characterization

    International Nuclear Information System (INIS)

    Millot, Romain; Hegan, Aimee; Négrel, Philippe

    2012-01-01

    Chemical and isotopic data for 23 geothermal water samples collected in New Zealand within the Taupo Volcanic Zone (TVZ) are reported. Major and trace elements including Li, B and Sr and their isotopic compositions (δ 7 Li, δ 11 B, 87 Sr/ 86 Sr) were determined in high temperature geothermal waters collected from deep boreholes in different geothermal fields (Ohaaki, Wairakei, Mokai, Kawerau and Rotokawa geothermal systems). Lithium concentrations are high (from 4.5 to 19.9 mg/L) and Li isotopic compositions (δ 7 Li) are homogeneous, ranging between −0.5‰ and +1.4‰. In particular, it is noteworthy that, except for the samples from the Kawerau geothermal field having slightly higher δ 7 Li values (+1.4%), the other geothermal waters have a near constant δ 7 Li signature around a mean value of 0‰ ± 0.6 (2σ, n = 21). Boron concentrations are also high and relatively homogeneous for the geothermal samples, falling between 17.5 and 82.1 mg/L. Boron isotopic compositions (δ 11 B) are all negative, and display a range between −6.7‰ and −1.9‰. These B isotope compositions are in agreement with those of the Ngawha geothermal field in New Zealand. Lithium and B isotope signatures are in a good agreement with a fluid signature mainly derived from water/rock interaction involving magmatic rocks with no evidence of seawater input. On the other hand, Sr concentrations are lower and more heterogeneous and fall between 2 and 165 μg/L. The 87 Sr/ 86 Sr ratios range from 0.70549 to 0.70961. These Sr isotope compositions overlap those of the Rotorua geothermal field in New Zealand, confirming that some geothermal waters (with more radiogenic Sr) have interacted with bedrocks from the metasedimentary basement. Each of these isotope systems on their own reveals important information about particular aspects of either water source or water/rock interaction processes, but, considered together, provide a more integrated understanding of the geothermal systems from

  10. Accurate isotope ratio mass spectrometry. Some problems and possibilities

    International Nuclear Information System (INIS)

    Bievre, P. de

    1978-01-01

    The review includes reference to 190 papers, mainly published during the last 10 years. It covers the following: important factors in accurate isotope ratio measurements (precision and accuracy of isotope ratio measurements -exemplified by determinations of 235 U/ 238 U and of other elements including 239 Pu/ 240 Pu; isotope fractionation -exemplified by curves for Rb, U); applications (atomic weights); the Oklo natural nuclear reactor (discovered by UF 6 mass spectrometry at Pierrelatte); nuclear and other constants; isotope ratio measurements in nuclear geology and isotope cosmology - accurate age determination; isotope ratio measurements on very small samples - archaeometry; isotope dilution; miscellaneous applications; and future prospects. (U.K.)

  11. Sr-Nd isotope systematics of xenoliths in Cenozoic volcanic rocks from SW Japan

    International Nuclear Information System (INIS)

    Kagami, Hiroo; Iwata, Masatoshi; Iizumi, Shigeru; Nureki, Terukazu.

    1993-01-01

    Based on new and previously published Sr and Nd isotope data, we examined the petrogenetic relationship between deep crust- and upper mantle-derived xenoliths contained in Cenozoic volcanic rocks and Cretaceous-Paleogene granitoid rocks in SW Japan. The deep crust- and upper mantle-derived mafic to ultramafic xenoliths contained in Cenozoic volcanic rocks from SW Japan have comparable initial Sr and Nd isotope ratios to the Cretaceous-Paleogene granitoid rocks in their respective districts. This may suggest that these xenoliths were genetically related to the Cretaceous-Paleogene granitoid rocks in SW Japan, and that regional variations in Sr and Nd isotope ratios observed in the granitoid rocks are attributed to differences in the geochemistry of the magma sources. (author)

  12. Pb, Sr and Nd isotope geological characteristics and its evolution of Jianchaling rock

    International Nuclear Information System (INIS)

    Pang Chunyong; Chen Minyang; Xu Wenxin

    2003-01-01

    It has been a long time debatable subject on the raw material source and its genesis of Jianchaling ultrabasic rock, because the original rock phases, the original mineral compositions, texture and structure, even part of the chemical components of the rocks had been changed completely after many periods and phases of metamorphism. According to the content of Pb, Rb, Sr, Nd elements and their Pb, Sr, Nd isotope compositions of the rocks, together with the isotope geological age of late magmatic activities, the authors analyze the evolution of Pb, Sr, Nd isotope compositions, The inferred initiate Nd isotope ratio of ultrabasic rocks is 0.510233, lower than that of meteorite unity at a corresponding period, its ε Nd(T)>O; The initiate Sr ratios inferred by the isotope geological age ranges from 0.702735 to 0.719028; Projecting the lead isotope compositions on the Pb tectonic evolution model, the result indicates that the raw material of Jianchaling ultrabasic rock coming from the deplete upper mantle. The ultrabasic magma which enrich of Mg, Ni and less S intruded the crust and formed the Jianchaling ultrabasic rock at late Proterozoic era (927 Ma±). The forming time of serpentinite is mostly equal to the granitoid intruding time, showing the intrusion o flate acidic magma caused a large scale alteration of the ultrabasic rocks and formed the meta-ultrabasic phase rock observed today. (authors)

  13. Identification of Marchfeld asparagus using Sr isotope ratio measurements by MC-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Swoboda, S; Brunner, M; Boulyga, S F; Galler, P; Prohaska, T [University of Natural Resources and Applied Life Sciences, Department of Chemistry-VIRIS Project, Vienna (Austria); Horacek, M [Austrian Research Centers GmbH, Seibersdorf (Austria)

    2008-01-15

    This work focuses on testing and application of Sr isotope signatures for the fast and reliable authentication and traceability of Asparagus officinalis originating from Marchfeld, Austria, using multicollector inductively coupled plasma mass spectrometry after optimised Rb/Sr separation. The major sample pool comprises freeze-dried and microwave-digested asparagus samples from Hungary and Slovakia which are compared with Austrian asparagus originating from the Marchfeld region, which is a protected geographical indication. Additional samples from Peru, the Netherlands and Germany were limited in number and allowed therefore only restricted statistical evaluation. Asparagus samples from Marchfeld were harvested within two subsequent years in order to investigate the annual variation. The results show that the Sr isotope ratio is consistent within these 2 years of investigation. Moreover, the Sr isotope ratio of total Sr in soil was found to be significantly higher than in an NH{sub 4}NO{sub 3} extract, reflecting the mobile (bioavailable) phase. The isotope composition in the latter extract corresponds well to the range found in the asparagus samples in Marchfeld, even though the concentration of Sr in asparagus shows no direct correlation to the concentration of Sr in the mobile phase of the soil. The major question was whether the 'Marchfelder Spargel' can be distinguished from samples from the neighbouring countries of Hungary and Slovakia. According to our findings, they can be clearly (100%) singled out from the Hungarian samples and can be distinguished from the Slovakian asparagus samples with a probability of more than 80%. (orig.)

  14. Identification of Marchfeld asparagus using Sr isotope ratio measurements by MC-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Swoboda, S.; Brunner, M.; Boulyga, S.F.; Galler, P.; Prohaska, T. [University of Natural Resources and Applied Life Sciences, Department of Chemistry-VIRIS Project, Vienna (Austria); Horacek, M. [Austrian Research Centers GmbH, Seibersdorf (Austria)

    2008-01-15

    This work focuses on testing and application of Sr isotope signatures for the fast and reliable authentication and traceability of Asparagus officinalis originating from Marchfeld, Austria, using multicollector inductively coupled plasma mass spectrometry after optimised Rb/Sr separation. The major sample pool comprises freeze-dried and microwave-digested asparagus samples from Hungary and Slovakia which are compared with Austrian asparagus originating from the Marchfeld region, which is a protected geographical indication. Additional samples from Peru, the Netherlands and Germany were limited in number and allowed therefore only restricted statistical evaluation. Asparagus samples from Marchfeld were harvested within two subsequent years in order to investigate the annual variation. The results show that the Sr isotope ratio is consistent within these 2 years of investigation. Moreover, the Sr isotope ratio of total Sr in soil was found to be significantly higher than in an NH{sub 4}NO{sub 3} extract, reflecting the mobile (bioavailable) phase. The isotope composition in the latter extract corresponds well to the range found in the asparagus samples in Marchfeld, even though the concentration of Sr in asparagus shows no direct correlation to the concentration of Sr in the mobile phase of the soil. The major question was whether the 'Marchfelder Spargel' can be distinguished from samples from the neighbouring countries of Hungary and Slovakia. According to our findings, they can be clearly (100%) singled out from the Hungarian samples and can be distinguished from the Slovakian asparagus samples with a probability of more than 80%. (orig.)

  15. Pb, Nd and Sr isotopes in oceanic ferromanganese deposits and ocean floor basalts

    International Nuclear Information System (INIS)

    O'Nions, R.K.; Carter, S.R.; Cohen, R.S.; Evensen, N.M.; Hamilton, P.J.

    1978-01-01

    The Pb-, Nd-, and Sr-isotope compositions of oceanic ferromanganese deposits, together with the Nd- and Sr-isotope compositions of altered ocean-floor basalts, are here reported. These data are used to evaluate these metals as sources in both the oceans and ocean ferromanganese deposits and the extent to which ocean-floor basalts may be a source of, or a sink for, these metals. (author)

  16. Effect of Wood Aging on Wine Mineral Composition and 87Sr/86Sr Isotopic Ratio.

    Science.gov (United States)

    Kaya, Ayse D; Bruno de Sousa, Raúl; Curvelo-Garcia, António S; Ricardo-da-Silva, Jorge M; Catarino, Sofia

    2017-06-14

    The evolution of mineral composition and wine strontium isotopic ratio 87 Sr/ 86 Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates. Sampling was carried out after 30, 60, and 90 days of aging, and the wines were evaluated in terms of general analysis, phenolic composition, total polysaccharides, multielement composition, and Sr IR. Li, Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, and Pb elements and 87 Sr/ 86 Sr were determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and Na, K, Ca, and Fe by flame atomic absorption spectrometry (FAAS). Two-way ANOVA was applied to assess wood aging and time effect on Sr IR and mineral composition. Wood aging resulted in significantly higher concentrations of Mg, V, Co, Ni, and Sr. At the end of the aging period, wine exhibited statistically identical Sr IR compared to control. Study suggests that wood aging does not affect 87 Sr/ 86 Sr, not precluding the use of this parameter for wine traceability purposes.

  17. Barite mineralization in Kalana speleothems, Central Estonia: Sr, S and O isotope characterization

    Directory of Open Access Journals (Sweden)

    Mikk Gaškov

    2017-06-01

    Full Text Available Barite mineralization in association with calcitic speleothem precipitates in cave structures in Silurian Aeronian carbonate rocks in Kalana quarry, Central Estonia, was studied. Barite mineralization in Kalana occurs in two generations – euhedral bladed-tabular barite zonal crystals from a few to 10 cm in size, growing on the limestone-dolomite wall-rock (generation I, and sparsely placed thin tabular crystals a few millimetres thick and up to 1 cm in size, growing on calcitic crusts (generation II. The barite crystals of generation I are frequently found embedded by paragenetically later calcitic botryoidal crusts. The Sr and S isotopic composition of barite crystals shows a trend of increasing Sr isotope ratios (from 0.7114 to 0.7120 and δ34S values (from 13‰ to 33‰ from the central parts towards the edges of zonal crystals. This suggests barite precipitation by mixing of two endmember fluids at varying ratios during barite formation: warm (up to 70 °C reducing fluid bearing Ba, characterized by an elevated radiogenic Sr- and 34S-enriched isotopic signal, and a cooler ambient fluid bearing an isotopically lighter dissolved sulphate, characterized by lower Sr isotope ratios. The excess of radiogenic 87Sr in barite compared to Phanerozoic seawater values suggests Sr derived from a continental source, whereas sulphate was derived either from oxidized H2S or a modified seawater source. Gradual increase in δ34S values towards the outer zones could also indicate the 34S enrichment due to bacterial sulphate reduction, even though there is no paired 34S and 18O enrichment of sulphate, characteristic of bacterial reworking. This can be interpreted as indicating an open system with limited sulphate resupply where the δ18O composition of sulphate was equilibrated with warm ascending hydrothermal fluid.

  18. Heterogeneity of the Caribbean plateau mantle source: Sr, O and He isotopic compositions of olivine and clinopyroxene from Gorgona Island

    Science.gov (United States)

    Révillon, S.; Chauvel, C.; Arndt, N. T.; Pik, R.; Martineau, F.; Fourcade, S.; Marty, B.

    2002-12-01

    The composition of the mantle plumes that created large oceanic plateaus such as Ontong Java or the Caribbean is still poorly known. Geochemical and isotopic studies on accreted portions of the Caribbean plateau have shown that the plume source was heterogeneous and contained isotopically depleted and relatively enriched portions. A distinctive feature of samples from the Caribbean plateau is their unusual Sr isotopic compositions, which, at a given Nd isotopic ratio, are far higher than in samples from other oceanic plateaus. Sr, O and He isotopic compositions of whole rocks and magmatic minerals (clinopyroxene or olivine) separated from komatiites, gabbros and peridotites from Gorgona Island in Colombia were determined to investigate the origin of these anomalously radiogenic compositions. Sequentially leached clinopyroxenes have Sr isotopic compositions in the range 87Sr/ 86Sr=0.70271-0.70352, systematically lower than those of leached and unleached whole rocks. Oxygen isotopic ratios of clinopyroxene vary within the range δ 18O=5.18-5.35‰, similar to that recorded in oceanic island basalts. He isotopic ratios are high ( R/ Ra=8-19). The lower 87Sr/ 86Sr ratios of most of the clinopyroxenes shift the field of the Caribbean plateau in Nd-Sr isotope diagrams toward more 'normal' values, i.e. a position closer to the field defined by mid-ocean ridge basalts and oceanic-island basalts. Three clinopyroxenes have slightly higher 87Sr/ 86Sr ratios that cannot be explained by an assimilation model. The high 87Sr/ 86Sr and variations of 143Nd/ 144Nd are interpreted as a source characteristic. Trace-element ratios, however, are controlled mainly by fractionation during partial melting. We combine these isotopic data in a heterogeneous plume source model that accounts for the diversity of isotopic signatures recorded on Gorgona Island and throughout the Caribbean plateau. The heterogeneities are related to old recycled oceanic lithosphere in the plume source; the high 3

  19. Isotopic reconstruction of ancient human migrations: A comprehensive Sr isotope reference database for France and the first case study at Tumulus de Sables, south-western France

    Science.gov (United States)

    Willmes, M.; Boel, C.; Grün, R.; Armstrong, R.; Chancerel, A.; Maureille, B.; Courtaud, P.

    2012-04-01

    Strontium isotope ratios (87Sr/86Sr) can be used for the reconstruction of human and animal migrations across geologically different terrains. Sr isotope ratios in rocks are a product of age and composition and thus vary between geologic units. From the eroding environment Sr is transported into the soils, plants and rivers of a region. Humans and animals incorporate Sr from their diet into their bones and teeth, where it substitutes for calcium. Tooth enamel contains Sr isotope signatures acquired during childhood and is most resistant to weathering and overprinting, while the dentine is often diagenetically altered towards the local Sr signature. For the reconstruction of human and animal migrations the tooth enamel 87Sr/86Sr ratio is compared to the Sr isotope signature in the vicinity of the burial site and the surrounding area. This study focuses on the establishment of a comprehensive reference map of bioavailable 87Sr/86Sr ratios for France. In a next step we will compare human and animal teeth from key archaeological sites to this reference map to investigate mobility. So far, we have analysed plant and soil samples from ~200 locations across France including the Aquitaine basin, the western and northern parts of the Paris basin, as well as three transects through the Pyrenees Mountains. The isotope data, geologic background information (BRGM 1:1M), field images, and detailed method descriptions are available through our online database iRhum (http://rses.anu.edu.au/research/ee). This database can also be used in forensic studies and food sciences. As an archaeological case study teeth from 16 adult and 8 juvenile individuals were investigated from an early Bell Beaker (2500-2000 BC) site at Le Tumulus des Sables, south-west France (Gironde). The teeth were analysed for Sr isotope ratios using laser ablation ICP-MS. Four teeth were also analysed using solution ICP-MS, which showed a significant offset to the laser ablation results. This requires further

  20. Sr isotopic evidence on the spilitic degradation of the Deccan basalt

    International Nuclear Information System (INIS)

    Subbarao, K.V.

    2000-01-01

    Similar Sr isotopic ratios (∼0.7055) for the tholeiite-spilite flow unit and the associated mineral phases, of Bombay (Deccan Traps) provide a direct evidence for the spilitic degradation of tholeiite. In contrast, a dramatic increase in the rare earth elements (REE) from basalt to spilite is rather puzzling as rare earths are considered to be relatively immobile. The geochemistry thus suggests that the process of spilitization is due to the reaction with a complex fluid having identical Sr-isotopic composition as that of the basaltic magma-thereby masking the details of the mixing process. (author)

  1. Sr and Nd isotope systematics in fish teeth

    International Nuclear Information System (INIS)

    Staudigel, H.; Zindler, A.

    1985-01-01

    High concentrations of Sr and Nd in fish teeth apatite (up to 2000 and 3800 ppm, respectively) make them relatively impervious to diagenetic overprints and allow high-precision analysis of 87 Sr/ 86 Sr and 143 Nd/ 144 Nd of very small amounts of material. 87 Sr/ 86 Sr ratios of 14 Cenozoic samples ( 87 Sr/ 86 Sr stratigraphic dating. A compilation of published 143 Nd/ 144 Nd data from recent Mn-nodules and marine Fe/Mn deposits shows that the North-Central Pacific Ocean and the major portion of the Atlantic Ocean display distinctly different, narrow ranges in isotopic compositions. Between these two areas, the 143 Nd/ 144 Nd of Mn-nodules vary systematically towards intermediate compositions in the Southern Oceans, reflecting the communication between the Atlantic and Pacific Oceans through the eastward moving Antarctic Circumpolar Current. The 143 Nd/ 144 Nd of the 2-55 Ma old fish teeth analyzed are typically close to the range of 143 Nd/ 144 Nd in Recent Mn-nodules and seawater for the respective ocean and, thus, indicate no significant change through this time period. The 143 Nd/ 144 Nd of fish teeth from the North Pacific Ocean are highest during periods of high aeolian sedimentation. (orig.)

  2. The use of Pb, Sr, and Hg isotopes in Great Lakes precipitation as a tool for pollution source attribution

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Laura S., E-mail: lsaylors@umich.edu [University of Michigan, Department of Earth and Environmental Sciences, 1100 N. University Ave., Ann Arbor, MI 48109 (United States); Blum, Joel D. [University of Michigan, Department of Earth and Environmental Sciences, 1100 N. University Ave., Ann Arbor, MI 48109 (United States); Dvonch, J. Timothy [University of Michigan, Air Quality Laboratory, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Gratz, Lynne E. [University of Washington-Bothell, 18115 Campus Way NE, Bothell, WA 98011 (United States); Landis, Matthew S. [U.S. EPA, Office of Research and Development, Research Triangle Park, NC 27709 (United States)

    2015-01-01

    The anthropogenic emission and subsequent deposition of heavy metals including mercury (Hg) and lead (Pb) present human health and environmental concerns. Although it is known that local and regional sources of these metals contribute to deposition in the Great Lakes region, it is difficult to trace emissions from point sources to impacted sites. Recent studies suggest that metal isotope ratios may be useful for distinguishing between and tracing source emissions. We measured Pb, strontium (Sr), and Hg isotope ratios in daily precipitation samples that were collected at seven sites across the Great Lakes region between 2003 and 2007. Lead isotope ratios ({sup 207}Pb/{sup 206}Pb = 0.8062 to 0.8554) suggest that Pb deposition was influenced by coal combustion and processing of Mississippi Valley-Type Pb ore deposits. Regional differences in Sr isotope ratios ({sup 87}Sr/{sup 86}Sr = 0.70859 to 0.71155) are likely related to coal fly ash and soil dust. Mercury isotope ratios (δ{sup 202}Hg = − 1.13 to 0.13‰) also varied among the sites, likely due to regional differences in coal isotopic composition, and fractionation occurring within industrial facilities and in the atmosphere. These data represent the first combined characterization of Pb, Sr, and Hg isotope ratios in precipitation collected across the Great Lakes region. We demonstrate the utility of multiple metal isotope ratios in parallel with traditional trace element multivariate statistical modeling to enable more complete pollution source attribution. - Highlights: • We measured Pb, Sr, and Hg isotopes in precipitation from the Great Lakes region. • Pb isotopes suggest that deposition was impacted by coal combustion and metal production. • Sr isotope ratios vary regionally, likely due to soil dust and coal fly ash. • Hg isotopes vary due to fractionation occurring within facilities and the atmosphere. • Isotope results support conclusions of previous trace element receptor modeling.

  3. Vadose Zone Infiltration Rate at Hanford, Washington, Inferred from Sr Isotope Measurements

    International Nuclear Information System (INIS)

    Maher, Katharine; DePaolo, Donald J.; Conrad, Mark E.; Serne, R. Jeffrey

    2003-01-01

    Sr isotope ratios were measured in the pore water, acid extracts, and sediments of a 70-m vadose zone core to obtain estimates of the long-term infiltration flux for a site in the Hanford/DOE complex in eastern Washington State. The 87Sr/86Sr values of the pore waters decrease systematically with depth, from a high value of 0.721 near the surface toward the bulk sediment average value of 0.711. Estimates of the bulk weathering rate combined with Sr isotopic data were used to constrain the long-term (century to millenial scale) natural diffuse infiltration flux for the site given both steady state and nonsteady state conditions. The models suggest that the infiltration fluc for the site is 7+- 3 mm/yr. The method shows potential for providing long-term in situ estimates of infiltration rates for deep heterogeneous vadose zones

  4. Rb-Sr and Sm-Nd Isotopic Studies of Lunar Green and Orange Glasses

    Science.gov (United States)

    Shih, C.-Y.; Nyquist, L. E.; Reese, Y.

    2012-01-01

    Lunar volcanic glassy beads have been considered as quenched basaltic magmas derived directly from deep lunar mantle during fire-fountaining eruptions [1]. Since these sub-mm size glassy melt droplets were cooled in a hot gaseous medium during free flight [2], they have not been subject to mineral fractionations. Thus, they represent primary magmas and are the best samples for the investigation of the lunar mantle. Previously, we presented preliminary Rb- Sr and Sm-Nd isotopic results for green and orange glassy samples from green glass clod 15426,63 and orange soil 74220,44, respectively [3]. Using these isotopic data, initial Sr-87/Sr-86 and Nd ratios for these pristine mare glass sources can be calculated from their respective crystallization ages previously determined by other age-dating techniques. These isotopic data were used to evaluate the mineralogy of the mantle sources. In this report, we analyzed additional glassy samples in order to further characterize isotopic signatures of their source regions. Also, we'll postulate a relationship between these two major mare basalt source mineralogies in the context of lunar magma ocean dynamics.

  5. Sr isotopes in natural waters: Applications to source characterisation and water-rock interaction in contrasting landscapes

    International Nuclear Information System (INIS)

    Shand, P.; Darbyshire, D.P.F.; Love, A.J.; Edmunds, W.M.

    2009-01-01

    Strontium isotopes ( 87 Sr/ 86 Sr) are routinely measured in hydrochemical studies to determine sources and mixing relationships. They have proved particularly useful in determining weathering processes and quantifying end-member mixing processes. A number of routine case studies are presented which highlight that Sr isotopes represent a powerful tool in the geochemists toolbox helping to constrain weathering reactions, weathering rates, flow pathways and mixing scenarios. Differences in methodologies for determining the weathering component in natural environments, inherent differences in weathering rates of different minerals, and mineral heterogeneity often cause difficulties in defining the weathering component of different catchments or aquifer systems. Nevertheless, Sr isotopes are useful when combined with other hydrochemical data, to constrain models of water-rock interaction and mixing as well as geochemical processes such as ion-exchange. This paper presents a summary of recent work by the authors in constraining the sources of waters and weathering processes in surface catchments and aquifers, and indicates cases where Sr isotopes alone are insufficient to solve hydrological problems.

  6. Sr isotopes in natural waters: Applications to source characterisation and water-rock interaction in contrasting landscapes

    Energy Technology Data Exchange (ETDEWEB)

    Shand, P., E-mail: paul.shand@csiro.au [CSIRO Land and Water/CRC LEME, Private Bag 2, Glen Osmond, SA 5064 (Australia); Darbyshire, D.P.F. [NERC Isotope Geosciences Laboratory, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG (United Kingdom); Love, A.J. [Department of Water, Land and Biodiversity Conservation, P.O. Box 2843, Adelaide 5001 (Australia); Edmunds, W.M. [School of Geography, Oxford University Centre for the Environment, South Parks Road, Oxford (United Kingdom)

    2009-04-15

    Strontium isotopes ({sup 87}Sr/{sup 86}Sr) are routinely measured in hydrochemical studies to determine sources and mixing relationships. They have proved particularly useful in determining weathering processes and quantifying end-member mixing processes. A number of routine case studies are presented which highlight that Sr isotopes represent a powerful tool in the geochemists toolbox helping to constrain weathering reactions, weathering rates, flow pathways and mixing scenarios. Differences in methodologies for determining the weathering component in natural environments, inherent differences in weathering rates of different minerals, and mineral heterogeneity often cause difficulties in defining the weathering component of different catchments or aquifer systems. Nevertheless, Sr isotopes are useful when combined with other hydrochemical data, to constrain models of water-rock interaction and mixing as well as geochemical processes such as ion-exchange. This paper presents a summary of recent work by the authors in constraining the sources of waters and weathering processes in surface catchments and aquifers, and indicates cases where Sr isotopes alone are insufficient to solve hydrological problems.

  7. Sr isotope tracing of multiple water sources in a complex river system, Noteć River, central Poland

    Energy Technology Data Exchange (ETDEWEB)

    Zieliński, Mateusz, E-mail: mateusz.zielinski@amu.edu.pl [Institute of Geoecology and Geoinformation, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań (Poland); Dopieralska, Jolanta, E-mail: dopieralska@amu.edu.pl [Poznań Science and Technology Park, Adam Mickiewicz University Foundation, Rubież 46, 61-612 Poznań (Poland); Belka, Zdzislaw, E-mail: zbelka@amu.edu.pl [Isotope Laboratory, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań (Poland); Walczak, Aleksandra, E-mail: awalczak@amu.edu.pl [Isotope Laboratory, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań (Poland); Siepak, Marcin, E-mail: siep@amu.edu.pl [Institute of Geology, Adam Mickiewicz University, Maków Polnych 16, 61-606 Poznań (Poland); Jakubowicz, Michal, E-mail: mjakub@amu.edu.pl [Institute of Geoecology and Geoinformation, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań (Poland)

    2016-04-01

    Anthropogenic impact on surface waters and other elements in the environment was investigated in the Noteć River basin in central Poland. The approach was to trace changes in the Sr isotope composition ({sup 87}Sr/{sup 86}Sr) and concentration in space and time. Systematic sampling of the river water shows a very wide range of {sup 87}Sr/{sup 86}Sr ratios, from 0.7089 to 0.7127. This strong variation, however, is restricted to the upper course of the river, whereas the water in the lower course typically shows {sup 87}Sr/{sup 86}Sr values around 0.7104–0.7105. Variations in {sup 87}Sr/{sup 86}Sr are associated with a wide range of Sr concentrations, from 0.14 to 1.32 mg/L. We find that strong variations in {sup 87}Sr/{sup 86}Sr and Sr concentrations can be accounted for by mixing of two end-members: 1) atmospheric waters charged with Sr from the near-surface weathering and wash-out of Quaternary glaciogenic deposits, and 2) waters introduced into the river from an open pit lignite mine. The first reservoir is characterized by a low Sr content and high {sup 87}Sr/{sup 86}Sr ratios, whereas mine waters display opposite characteristics. Anthropogenic pollution is also induced by extensive use of fertilizers which constitute the third source of Sr in the environment. The study has an important implication for future archeological studies in the region. It shows that the present-day Sr isotope signatures of river water, flora and fauna cannot be used unambiguously to determine the “baseline” for bioavailable {sup 87}Sr/{sup 86}Sr in the past. - Highlights: • Sr isotopes fingerprint water sources and their interactions in a complex river system. • Mine waters and fertilizers are critical anthropogenic additions in the river water. • Limited usage of environmental isotopic data in archeological studies. • Sr budget of the river is dynamic and temporary.

  8. A Sr-isotopic comparison between thermal waters, rocks, and hydrothermal calcites, Long Valley caldera, California

    Science.gov (United States)

    Goff, F.; Wollenberg, H.A.; Brookins, D.C.; Kistler, R.W.

    1991-01-01

    The 87Sr/86Sr values of thermal waters and hydrothermal calcites of the Long Valley caldera geothermal system are more radiogenic than those of young intracaldera volcanic rocks. Five thermal waters display 87Sr/86Sr of 0.7081-0.7078 but show systematically lighter values from west to east in the direction of lateral flow. We believe the decrease in ratio from west to east signifies increased interaction of deeply circulating thermal water with relatively fresh volcanic rocks filling the caldera depression. All types of pre-, syn-, and post-caldera volcanic rocks in the west and central caldera have (87Sr/86Sr)m between about 0.7060 and 0.7072 and values for Sierra Nevada granodiorites adjacent to the caldera are similar. Sierran pre-intrusive metavolcanic and metasedimentary rocks can have considerably higher Sr-isotope ratios (0.7061-0.7246 and 0.7090-0.7250, respectively). Hydrothermally altered volcanic rocks inside the caldera have (87Sr/86Sr)m slightly heavier than their fresh volcanic equivalents and hydrothermal calcites (0.7068-0.7105) occupy a midrange of values between the volcanic/plutonic rocks and the Sierran metamorphic rocks. These data indicate that the Long Valley geothermal reservoir is first equilibrated in a basement complex that contains at least some metasedimentary rocks. Reequilibration of Sr-isotope ratios to lower values occurs in thermal waters as convecting geothermal fluids flow through the isotopically lighter volcanic rocks of the caldera fill. ?? 1991.

  9. Analytical procedures for determining Pb and Sr isotopic compositions in water samples by ID-TIMS

    Directory of Open Access Journals (Sweden)

    Veridiana Martins

    2008-01-01

    Full Text Available Few articles deal with lead and strontium isotopic analysis of water samples. The aim of this study was to define the chemical procedures for Pb and Sr isotopic analyses of groundwater samples from an urban sedimentary aquifer. Thirty lead and fourteen strontium isotopic analyses were performed to test different analytical procedures. Pb and Sr isotopic ratios as well as Sr concentration did not vary using different chemical procedures. However, the Pb concentrations were very dependent on the different procedures. Therefore, the choice of the best analytical procedure was based on the Pb results, which indicated a higher reproducibility from samples that had been filtered and acidified before the evaporation, had their residues totally dissolved, and were purified by ion chromatography using the Biorad® column. Our results showed no changes in Pb ratios with the storage time.

  10. Stable and Radiogenic Sr Isotopes in Barite - Clues on the Links Between Weathering, Climate and the C Cycle

    Science.gov (United States)

    Paytan, A.; Eisenhauer, A.; Wallmann, K. J. G.; Griffith, E. M.; Ridgwell, A.

    2017-12-01

    The radiogenic Sr-isotopic signature (87Sr/86Sr) of seawater fluctuates primarily in response to changes in the inputs of Sr from weathering and hydrothermal activity, which have distinct 87Sr/86Sr values. Changes in the isotopic ratio of the weathered terrain also contribute to observed changes in 87Sr/86Sr. The stable Sr-isotope ratios in seawater (mass dependent isotopic fractionation; δ88/86Sr) fluctuate primarily in response to the rate of calcium carbonate (CaCO3) accumulation at the seafloor. Together the radiogenic and stable Sr can constrain the coupling between weathering and sedimentation and shed light on the relation between weathering, CaCO3 deposition, the global carbon (C) cycle and climate. Reconstruction of the coupled stable and radiogenic Sr seawater curves over the past 35 Ma of Earth history indicates that the location and rate of CaCO3 burial in the ocean fluctuated considerably over the past 35 Ma. Between 35 to 18 Ma a reduction in neritic CaCO3 burial and increased burial in pelagic settings is observed. The trend was reversed between 20 and 3 Ma and finally over the last 3 million years a rapid change from neritic to pelagic burial is seen. The lack of continues increase of pelagic CaCO3 burial rates suggests that silicate weathering rates have not increased monotonically over the past 35 Ma implying strong feedbacks operating in the climate system - lower atmospheric pCO2 and cooling trends (which control chemical weathering as seen from carbonate deposition in the ocean) countered the effects of uplift (which controls physical weathering) - modulating weathering rates and preventing a runaway ice-house. In addition the data suggests considerable fluctuations in seawater Sr concentrations over time. These data demonstrate how using multiple isotope proxies can help constrain interpretations of the geological record.

  11. Grain size effect on Sr and Nd isotopic compositions in eolian dust. Implications for tracing dust provenance and Nd model age

    International Nuclear Information System (INIS)

    Feng Jinliang; Zhu Liping; Zhen Xiaolin; Hu Zhaoguo

    2009-01-01

    Strontium (Sr) and neodymium (Nd) isotopic compositions enable identification of dust sources and reconstruction of atmospheric dispersal pathways. The Sr and Nd isotopic compositions in eolian dust change systematically with grain size in ways not yet fully understood. This study demonstrates the grain size effect on the Sr and Nd isotopic compositions in loess and 2006 dust fall, based on analyses of seven separated grain size fractions. The analytical results indicate that Sr isotopic ratios strongly depend on the grain size fractions in samples from all types of eolian dust. In contrast, the Nd isotopic ratios exhibit little variation in loess, although they vary significantly with grain size in samples from a 2006 dust fall. Furthermore, Nd model ages tend to increase with increasing grain size in samples from all types of eolian dust. Comparatively, Sr isotopic compositions exhibit high sensitively to wind sorting, while Nd isotopic compositions show greater sensitively to dust origin. The principal cause for the different patterns of Sr and Nd isotopic composition variability with grain size appears related to the different geochemical behaviors between rubidium (Rb) and Sr, and the similar geochemical behaviors between samarium (Sm) and Nd. The Nd isotope data indicate that the various grain size fractions in loess have similar origins for each sample. In contrast, various provenance components may separate into different grain size fractions for the studied 2006 dust fall. The Sr and Nd isotope compositions further confirm that the 2006 dust fall and Pleistocene loess in Beijing have different sources. The loess deposits found in Beijing and those found on the Chinese Loess Plateau also derive from different sources. Variations between Sr and Nd isotopic compositions and Nd model ages with grain size need to be considered when directly comparing analyses of eolian dust of different grain size. (author)

  12. Derivation of Apollo 14 High-Al Basalts at Discrete Times: Rb-Sr Isotopic Constraints

    Science.gov (United States)

    Hui. Hejiu; Neal, Clive, R.; Shih, Chi-Yu; Nyquist, Laurence E.

    2012-01-01

    Pristine Apollo 14 (A-14) high-Al basalts represent the oldest volcanic deposits returned from the Moon [1,2] and are relatively enriched in Al2O3 (>11 wt%) compared to other mare basalts (7-11 wt%). Literature Rb-Sr isotopic data suggest there are at least three different eruption episodes for the A-14 high-Al basalts spanning the age range approx.4.3 Ga to approx.3.95 Ga [1,3]. Therefore, the high-Al basalts may record lunar mantle evolution between the formation of lunar crust (approx.4.4 Ga) and the main basin-filling mare volcanism (groups [5,6], and then regrouped into three with a possible fourth comprising 14072 based on the whole-rock incompatible trace element (ITE) ratios and Rb-Sr radiometric ages [7]. However, Rb-Sr ages of these basalts from different laboratories may not be consistent with each other because of the use of different 87Rb decay constants [8] and different isochron derivation methods over the last four decades. This study involved a literature search for Rb-Sr isotopic data previously reported for the high-Al basalts. With the re-calculated Rb-Sr radiometric ages, eruption episodes of A-14 high-Al basalts were determined, and their petrogenesis was investigated in light of the "new" Rb-Sr isotopic data and published trace element abundances of these basalts.

  13. Nd and Sr isotopic variations in acidic rocks from Japan: significance of upper-mantle heterogeneity

    Science.gov (United States)

    Terakado, Yasutaka; Nakamura, Noboru

    1984-10-01

    Initial Nd and Sr isotopic ratios have been measured for Cretaceous acidic and related intermediate rocks (24 volcanic and two plutonic rocks) from the Inner Zone of Southwest Japan (IZSWJ) to investigate the genesis of acidic magmas. The initial Nd and Sr isotopic ratios for these rocks show three interesting features: (1) ɛ Nd values for acidic rocks (+2 to -9) are negatively correlated with ɛ Sr values (+10 to +90) together with those for intermediate rocks ( ɛ Nd=+3 to -8; ɛ Sr=0 to +65). (2) The ɛ Nd values for silica rich rocks (>60% SiO2) correlate with the longitude of the sample locality, decreasing from west to east in a stepwise fashion: Four areas characterized by uniform ɛ Nd values are discriminated. (3) Low silica rocks (Japan suggest that the acidic rocks can be formed neither by fractional crystallization processes from more basic magmas nor by crustal assimilation processes. The isotopic variations of the acidic rocks may reflect regional isotopic heterogeneity in the lower crust, and this heterogeneity may ultimately be attributed to the regional heterogeneity of the uppermost-mantle beneath the Japanese Islands.

  14. Further Sr and Nd isotopic results from peridotites of the Ronda Ultramafic Complex

    International Nuclear Information System (INIS)

    Reisberg, L.; Zindler, A.

    1989-01-01

    Clinopyroxenes derived from peridotites of the spinel and garnet facies of the Ronda Ultramafic Complex yield Sr and Nd isotopic ratios which extend the range of compositions found in the massif to values as depleted as 0.70205 for Sr and 0.51363 for Nd. Large-amplitude, short-wavelength isotopic variations are found to be uniquitous throughout the massif. In the garnet facies, some of these variations are shown to be produced by the tectonic disaggregation of mafic layers in an isotopically depleted peridotite matrix. Ages obtained from garnet-clinopyroxene Sm-Nd isochrons (about 22 m.y.) agree with previous determinations of the time of crustal emplacement. In the plagioclase facies, where the Sr and Nd isotopic compositions have been very strongly affected by recent cryptic metasomatism, detailed study of one sample reveals that intermineral Nd isotopic equilibrium exists between clinopyroxene, orthopyroxene, and plagioclase. This indicates that the metasomatism occurred at high temperatures, and thus probably within the mantle. A rough correlation between 143 Nd/ 144 Nd and 147 Sm/ 144 N, with an apparent 'age' of 1.3 b.y. and an initial ε Nd (0) value of +6.0, is observed among clinopyroxenes derived from river sediments from throughout the massif. This age is interpreted as the time that the massif left the convecting mantle and became incorporated into the sub-continental lithosphere. (orig.)

  15. Archean and proterozoic in the West-European Hercynian chain: isotopic geochemistry (Sr-Nd-Pb) and U-Pb geochronology on zircons

    International Nuclear Information System (INIS)

    Guerrot, C.

    1989-01-01

    The first part of this research thesis reports the study of isotopic (Sr-Nd-Pb) geochemistry and U-Pb geochronology on zircons in the immersed granulites of the Bay of Biscay: U-Pb geochronology on zircons, Nd isotopic geochemistry, Sr isotopic geochemistry, common Pb, Rb-Sr, Sm-Nd and rare earth data on minerals, comparison with other European granulites, comparison with West-Africa, study of Archean and proterozoic in the Hercynian chain. The second part reports the study of the U-Pb geochronology on zircon in the Cadomian, and the third part addresses the Sr-Nd isotopic geochemistry of some Cadomian granitoid, and the crust contamination in different regions [fr

  16. Multiple enrichment of the Carpathian-Pannonian mantle: Pb-Sr-Nd isotope and trace element constraints

    Science.gov (United States)

    Rosenbaum, Jeffrey M.; Wilson, Marjorie; Downes, Hilary

    1997-07-01

    Pb isotope compositions of acid-leached clinopyroxene and amphibole mineral separates from spinel peridotite mantle xenoliths entrained in Tertiary-Quaternary alkali basalts from the Carpathian-Pannonian Region of eastern Europe provide important constraints on the processes of metasomatic enrichment of the mantle lithosphere in an extensional tectonic setting associated with recent subduction. Principal component analysis of Pb-Sr-Nd isotope and rare earth element compositions of the pyroxenes is used to identify the geochemical characteristics of the original lithospheric mantle protolith and a spectrum of infiltrating metasomatic agents including subduction-related aqueous fluids and silicate melts derived from a subduction-modified mantle wedge which contains a St. Helena-type (HIMU) plume component. The mantle protolith is highly depleted relative to mid-ocean ridge basalt-source mantle with Pb-Nd-Sr isotope compositions consistent with an ancient depletion event. Silicate melt infiltration into the protolith accounts for the primary variance in the Pb-Sr-Nd isotope compositions of the xenoliths and has locally generated metasomatic amphibole. Infiltration of aqueous fluids has introduced radiogenic Pb and Sr without significantly perturbing the rare earth element signature of the protolith. The Pb isotope compositions of the fluid-modified xenoliths suggest that they reacted with aqueous fluids released from a subduction zone which had equilibrated with sediment derived from an ancient basement terrain. We propose a model for mantle lithosphere evolution consistent with available textural and geochemical data for the xenolith population. The Pb-Sr-Nd isotope compositions of both alkaline mafic magmas and rare, subduction-related, calc-alkaline basaltic andesites from the region provide important constraints for the nature of the asthenospheric mantle wedge and confirm the presence of a HIMU plume component. These silicate melts contribute to the metasomatism

  17. Sr isotope zoning in plagioclase from andesites at Cabo De Gata, Spai

    DEFF Research Database (Denmark)

    Waight, Tod Earle; Tørnqvist, Jakob

    2018-01-01

    Plagioclase crystals in andesites from the Cabo De Gata region show generally radiogenic Sr isotope compositions and consistent core to rim increases in 87Sr/86Sr that are indicative of open system processes in the lithosphere and crustal contamination during crystallization. High-grade metamorphic...... rocks of the Alpujárride and Nevado-Filábride complexes represent the most likely crustal contaminants. The plagioclases are characterized by subtly zoned and resorbed calcic cores (An73-86). These cores also have radiogenic 87Sr/86Sr (0.7127-0.7129), although less radiogenic than plagioclase rims......, groundmass plagioclase and whole rock compositions (up to 87Sr/86Sr = 0.7135). These cores are interpreted to represent early crystallization of plagioclase from hydrous melts emplaced into the lower crust. The parental melts to these andesites must therefore have already inherited their radiogenic Sr...

  18. Ca and Sr isotope records support ocean acidification during end-Permian mass extinction

    Science.gov (United States)

    Wang, J.; Jacobson, A. D.; Zhang, H.; Ramezani, J.; Sageman, B. B.; Hurtgen, M.; Bowring, S. A.; Shen, S.

    2017-12-01

    The end-Permian mass extinction represents the most devastating loss of biodiversity during the Phanerozoic. A negative carbon isotope (δ13C) excursion that accompanies the event suggests a significant perturbation to the global carbon cycle, likely induced by CO2 emissions during eruption of the Siberian Traps large igneous province. The carbon cycle is linked with the Ca and Sr cycles through chemical weathering and carbonate precipitation. Therefore, analyses of Ca (δ44/40Ca), radiogenic Sr (87Sr/86Sr), and stable Sr (δ88/86Sr) isotope abundance variations in marine carbonate rocks spanning the Permian-Triassic Boundary (PTB) can reveal key information about biogeochemical changes that occurred during this time. We report δ44/40Ca, 87Sr/86Sr, and δ88/86Sr records analyzed by TIMS for the Meishan and Dajiang sections in China. δ44/40Ca values exhibit similar patterns in both sections. The values remain unchanged across the extinction event layer (EXT) and then decrease by 0.20‰ before increasing by 0.20‰ to 0.40‰ around the PTB. In the Meishan section, 87Sr/86Sr ratios increase after the EXT and return to pre-excursion levels by the PTB. Simultaneously, δ88/86Sr values decrease by 0.12‰ across the EXT and increase by 0.08‰ by the PTB. The patterns of our data support the hypothesis that elevated atmospheric CO2 levels enhanced chemical weathering inputs and might have caused transient ocean acidification, with an "alkalinity overshoot" and increased carbonate deposition occurring after the extinction. Additional measurements and model calculations are underway to help refine and improve these preliminary interpretations.

  19. Optical isotope shifts of sup(80,82)Sr from coincidence laser spectroscopy

    International Nuclear Information System (INIS)

    Eastham, D.A.; Walker, P.M.; Smith, J.R.H.; Griffith, J.A.R.; Evans, D.E.; Wells, S.A.; Fawcett, M.J.; Grant, I.S.

    1986-01-01

    The isotope shifts of radioactive sup(80,82)Sr have been measured by a new, ultrasensitive, laser fluorescence technique. The results have been used to calculate changes in nuclear charge radii. The values, together with those of nearby stable isotopes, are discussed in terms of changes in the static and dynamic nuclear deformations. (author)

  20. Ca, Sr and Ba stable isotopes reveal the fate of soil nutrients along a tropical climosequence

    Science.gov (United States)

    Bullen, Thomas D.; Chadwick, Oliver A.

    2016-01-01

    Nutrient biolifting is an important pedogenic process in which plant roots obtain inorganic nutrients such as phosphorus (P) and calcium (Ca) from minerals at depth and concentrate those nutrients at the surface. Here we use soil chemistry and stable isotopes of the alkaline earth elements Ca, strontium (Sr) and barium (Ba) to test the hypothesis that biolifting of P has been an important pedogenic process across a soil climosequence developed on volcanic deposits at Kohala Mountain, Hawaii. The geochemical linkage between these elements is revealed as generally positive site-specific relationships in soil mass gains and losses, particularly for P, Ba and Ca, using the ratio of immobile elements titanium and niobium (Ti/Nb) to link individual soil samples to a restricted compositional range of the chemically and isotopically diverse volcanic parent materials. At sites where P is enriched in surface soils relative to abundances in deeper soils, the isotope compositions of exchangeable Ca, Sr and Ba in the shallowest soil horizons ( 10 cm depth) at those sites is consistently heavier than the volcanic parent materials. The isotope compositions of exchangeable Ca and Sr trend toward heavier compositions with depth more gradually, reflecting increasing leakiness from these soils in the order Ba < Sr < Ca and downward transfer of light biocycled Ca and Sr to deeper exchange sites. Given the long-term stability of ecosystem properties at the sites where P is enriched in surface soils, a simple box model demonstrates that persistence of isotopically light exchangeable Ca, Sr and Ba in the shallowest soil horizons requires that the uptake flux to plants from those near-surface layers is less than the recycling flux returned to the surface as litterfall. This observation implicates an uptake flux from an additional source which we attribute to biolifting. We view the heavy exchangeable Ba relative to soil parent values in deeper soils at sites where P is enriched in

  1. Temporal variations of Sr isotopic compositions for the rocks from Dogo, Oki islands Shimane Prefecture

    International Nuclear Information System (INIS)

    Fujimaki, Hirokazu; Xu Hong; Aoki, Ken-ichiro

    1991-01-01

    Fifty-three volcanic rocks from Dogo island, Oki, Shimane Prefecture, southwestern Japan were analyzed for Sr isotopic compositions with two basement rocks. The rock samples consist of calc-alkali rock suite, Nagaoda shoshonite-banakite suite, Oki trachyte-rhyolite suite, Dogo mugearite suite, Hei trachyte and Tsuzurao rhyolite series, and Daimanjiyama, Ohmine, Kuroshima, Shiroshimazaki, Saigo, and Misaki alkali basalt groups in the order of probable eruption sequence. The volcanic rocks of calc-alkali suite and shoshonite-banakite suite were produced before Japan Sea opening (ca. 15 Ma), and both have 87 Sr/ 86 Sr ratios higher than 0.7068. Long after Japan Sea opening Oki-trachyte-rhyolite suite was erupted (ca. 6.6 Ma); they have rather low 87 Sr/ 86 Sr ratios (0.7066-0.7081). Mugearites followed and have similar Sr isotopic composition, whereas 4.6 Ma old Daimanjiyama basalts have clearly low 87 Sr/ 86 Sr ratios (0.7050-0.7051). The rocks erupted 3-4 Ma seem to have the lowest 87 Sr/ 86 Sr ratios; they are Ohmine, Kuroshima, Shiroshimazaki alkali basalt suites (0.7044-0.7048). The 87 Sr/ 86 Sr ratios of the Saigo basalts erupted 0.84 Ma are higher than those erupted 3-4 Ma. The latest volcanic products in Dogo island, Misaki basalt suite has even higher 87 Sr/ 86 Sr ratios (0.7054-0.7057) than the Saigo basalt suite. Thus, temporal and systematic variation of Sr isotopic compositions of the volcanic rocks from Dogo can be recognized. The 87 Sr/ 86 Sr ratios of the rocks were once as high as 0.7066 or even higher than 0.708, but they started decreasing down to ca. 0.7044-0.7048 4-3 Ma ago. Since then the ratios rebounded to 0.7049-0.7055. The Hei trachyte and Tsuzurao rhyolite series are not included in this temporal and systematic change. The mantle diapir associated with Japan Sea spreading might have caused the decrease in the ratios, and either Pacific Ocean plate or Philippine Sea plate subduction may be responsible for this rebound. (author)

  2. Sr-Nd-Hf Isotopic Analysis of <10 mg Dust Samples: Implications for Ice Core Dust Source Fingerprinting

    DEFF Research Database (Denmark)

    Ujvari, Gabor; Wegner, Wencke; Klötzli, Urs

    2018-01-01

    Combined Sr‐Nd‐Hf isotopic data of two reference materials (AGV‐1/BCR2) and 50, 10, and 5 mg aliquots of carbonate‐free fine grain (isotopic...... compositions (ICs) demonstrate that robust isotopic ratios can be obtained from 5 to 10 mg size rock samples using the ion exchange/mass spectrometry techniques applied. While 87Sr/86Sr ratios of dust aluminosilicate fractions are affected by even small changes in pretreatments, Nd isotopic ratios are found...... to be insensitive to acid leaching, grain‐size or weathering effects. However, the Nd isotopic tracer is sometimes inconclusive in dust source fingerprinting (BEI and NUS both close to ɛNd(0) –10). Hafnium isotopic values (

  3. Petrogenesis of ultramafic xenoliths from Hawaii inferred from Sr, Nd, and Pb isotopes

    Science.gov (United States)

    Okano, Osamu; Tatsumoto, Mitsunobu

    Isotopic compositions of Nd, Sr, and Pb in xenoliths in the Honolulu volcanic series from the Salt Lake Crater (H-type) are similar to those of the host post-erosional basalts, but are distinct from the magma sources of Koolau shield tholeiites and MORB. In contrast, one spinel Iherzolite (K-type) has isotopic compositions of Nd and Sr that are close to those of Koolau tholeiite rather than to the other Hawaiian basalts. Previous studies have shown that Sr isotopic composition of the xenoliths and the host basalt and that trace element concentrations in minerals of garnet Iherzolites from Honolulu basalt were nearly in equilibrium with the host magma, indicating that Honolulu volcanics were derived from garnet Iherzolite or similar material. However, differences exist among the isotopic compositions (especially Nd) of the xenoliths indicating that they are accidental inclusions from upper layers. The similarity in isotopic compositions between xenoliths and Honolulu basalt suggests that the source areas in the mantle are chemically similar. Correlation of 238U/204Pb vs. 206Pb/204Pb of chrome diopside separated from the H-type spinel Iherzolites indicates that the xenoliths are 80±36 Ma, which corresponds to the lithosphere age of the Hawaiian site. This age is consistent with petrological studies [e.g., Sen and Leeman, 1991] which have found that the spinel Iherzolite inclusions are derived from the lithosphere wall rocks. The ɛNd = ˜+8 of the H-xenoliths is slightly lower than that for the East Pacific Rise MORB indicating that the xenoliths are derived from a trace element depleted source similar to the MORB residue. If the garnet Iherzolite xenoliths are derived from mixture of spinel Iherzolite with intrusive pyroxenite, then the source of the pyroxenite contained little plume component. The one exceptional spinel Iherzolite xenolith may be a residue of Koolau-like tholeiitic magma or may have been metasomatized by Koolau volcanism in the deep lithosphere

  4. The Origin and Evolution of Nucleosynthetic Sr Isotope Variability in Calcium and Aluminum-rich Refractory Inclusions

    Science.gov (United States)

    Myojo, Kunihiro; Yokoyama, Tetsuya; Okabayashi, Satoki; Wakaki, Shigeyuki; Sugiura, Naoji; Iwamori, Hikaru

    2018-01-01

    Nucleosynthetic isotope anomalies in meteorites are useful for investigating the origin of materials in the protoplanetary disk and dynamical processes of planetary formation. In particular, calcium and aluminum-rich inclusions (CAIs) found in chondrites are key minerals for decoding the initial conditions of the solar system before the accretion of small planetary bodies. In this study, we report isotopic analyses for three Allende CAIs, fluffy type A (FTA), type B, and fine-grained spinel rich (FS) inclusions, with a specific emphasis on the measurements of 84Sr/86Sr ratios. It was found that the average μ 84Sr values (106 relative deviations from a standard material) were 175, 129, and 56 ppm for the samples of FTA, type B, and FS inclusions, respectively. Additionally, the FTA samples exhibited heterogeneous μ 84Sr values, while those for the type B and FS inclusions were homogeneous within individual inclusions. The elevated μ 84Sr values were most likely explained by the relative enrichment of r-process nuclides in the CAI formation region. The variation of μ 84Sr values between the FTA and type B inclusions, as well as within the FTA inclusion, suggests the presence of multiple CAI source reservoirs with distinct isotopic compositions, which is either inherited from isotopic heterogeneity in the molecular cloud or caused by the selective destruction of r-process-enriched supernova grains via nebular thermal processing. On the other hand, the reaction between a refractory precursor of the FS inclusion and a gaseous reservoir enriched in Mg, Si, and 16O resulted in the lowest μ 84Sr values for the FS inclusion.

  5. Geological, Geochemical 1 and Rb-Sr isotopic studies on tungsten 2 ...

    Indian Academy of Sciences (India)

    37

    Geological, Geochemical and Rb-Sr isotopic studies on tungsten. 1 mineralised ..... From the field relations it is demonstrated that SG (biotite-bearing granitic gneiss) and. 120 ..... cases Ba) and vice-versa for the low concentration. 291.

  6. Environmental isotopes (18O, 2H, and 87Sr/86Sr) as a tool in groundwater investigations in the Keta Basin, Ghana

    Science.gov (United States)

    Jørgensen, Niels; Banoeng-Yakubo, Bruce

    2001-03-01

    Analyses of environmental isotopes (18O, 2H, and 87Sr/86Sr) are applied to groundwater studies with emphasis on saline groundwater in aquifers in the Keta Basin, Ghana. The 87Sr/86Sr ratios of groundwater and surface water of the Keta Basin primarily reflect the geology and the mineralogical composition of the formations in the catchments and recharge areas. The isotopic compositions of 18O and 2H of deep groundwater have small variations and plot close to the global meteoric water line. Shallow groundwater and surface water have considerably larger variations in isotopic compositions, which reflect evaporation and preservation of seasonal fluctuations. A significant excess of chloride in shallow groundwater in comparison to the calculated evaporation loss is the result of a combination of evaporation and marine sources. Groundwaters from deep wells and dug wells in near-coastal aquifers are characterized by relatively high chloride contents, and the significance of marine influence is evidenced by well-defined mixing lines for strontium isotopes, and hydrogen and oxygen stable isotopes, with isotopic compositions of seawater as one end member. The results derived from environmental isotopes in this study demonstrate that a multi-isotope approach is a useful tool to identify the origin and sources of saline groundwater. Résumé. L'analyse des isotopes du milieu (18O, 2H, et 87Sr/86Sr) a été mise en œuvre pour des études hydrogéologiques portant sur des eaux souterraines salées des aquifères du bassin de Keta (Ghana). Les rapports isotopiques 87Sr/86Sr de l'eau souterraine et de l'eau de surface du bassin de Keta reflètent principalement la géologie et la composition minéralogique des formations des bassins d'alimentation et des zones de recharge. Les compositions isotopiques en 18O et en 2H des eaux souterraines profondes présentent de faibles variations et se placent près de la droite des eaux météoriques mondiales. Les eaux des nappes peu profondes

  7. 87Sr/86Sr Concentrations in the Appalachian Basin: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Mordensky, Stanley P. [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); National Energy Technology Lab. (NETL), Albany, OR (United States); Lieuallen, A. Erin [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); National Energy Technology Lab. (NETL), Albany, OR (United States); Verba, Circe [National Energy Technology Lab. (NETL), Albany, OR (United States); Hakala, Alexandra [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2016-06-16

    This document reviews 87Sr/86Sr isotope data across the Appalachian Basin from existing literature to show spatial and temporal variation. Isotope geochemistry presents a means of understanding the geochemical effects hydraulic fracturing may have on shallow ground substrates. Isotope fractionation is a naturally occurring phenomenon brought about by physical, chemical, and biological processes that partition isotopes between substances; therefore, stable isotope geochemistry allows geoscientists to understand several processes that shape the natural world. Strontium isotopes can be used as a tool to answer an array of geological and environmental inquiries. In some cases, strontium isotopes are sensitive to the introduction of a non-native fluid into a system. This ability allows strontium isotopes to serve as tracers in certain systems. Recently, it has been demonstrated that strontium isotopes can serve as a monitoring tool for groundwater and surface water systems that may be affected by hydraulic fracturing fluids (Chapman et al., 2013; Kolesar Kohl et al., 2014). These studies demonstrated that 87Sr/86Sr values have the potential to monitor subsurface fluid migration in regions where extraction of Marcellus Shale gas is occurring. This document reviews publicly available strontium isotope data from 39 sample locations in the Appalachian Basin (Hamel et al., 2010; Chapman et al., 2012; Osborn et al., 2012; Chapman et al., 2013; Capo et al., 2014; Kolesar Kohl et al., 2014). The data is divided into two sets: stratigraphic (Upper Devonian/Lower Mississippi, Middle Devonian, and Silurian) and groundwater. ArcMap™ (ESRI, Inc.) was used to complete inverse distance weighting (IDW) analyses for each dataset to create interpolated surfaces in an attempt to find regional trends or variations in strontium isotopic values across the Appalachian Basin. 87Sr/86Sr varies up to ~ 0.011 across the

  8. Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the Southern Andes

    Science.gov (United States)

    Futa, K.; Stern, C.R.

    1988-01-01

    Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46??S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54??S) range for 87Sr 86Sr from 0.70280 to 0.70591 and for 143Nd 144Nd from 0.51314 to 0.51255. The ranges are significantly greater than previously reported from the southern Andes but are different from the isotopic compositions of volcanoes in the central and northern Andes. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have 87Sr 86Sr, 143Nd 144Nd, La Yb, Ba La, and Hf Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35??S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33?? and 34??S, basaltic andesites and andesites have higher 87Sr 86Sr, Rb Cs, and Hf Lu, and lower 143Nd 144Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54??S) has Sr and Nd isotopic compositions and K Rb and Ba La similar to MORB. The high La Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO2, K2O, Rb, Ba, Ba La, and 87Sr 86Sr and decrease in MgO, Sr, K Rb, Rb Cs, and 143Nd 144Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra

  9. 143Nd/144Nd and 87Sr/86Sr isotope ratio variations in magmatic rocks of Aleutian island arc as regard to the problem of their petrogenesis

    International Nuclear Information System (INIS)

    Zhuravlev, D.Z.; Chernyshev, I.V.; Tsvetkov, A.A.; Borsuk, A.M.; Agapova, A.A.; Serdyuk, N.I.

    1983-01-01

    The results of precision measurement of isotope composition of neodymium in rocks of Pre-Quaternary magmatic formations of the Aleutian island arc (AIA) (Commander Islands). It has been found summing the Nd and Sr analysis results in AIA magmatic rocks that AIA magmatic melts are of mantle origin. The AIA magma source the full its length off and for all the history of geological development remained isotopically homogeneousm Crust contamination of magmatic melts played a significant role only in the initial and early stages of the AIA development, in the later and conclusive stages this process has been sharply reduced. Sedimentary material practically did not take part in the magmaproduction process at the initial stage of the AIA development, it is hardly probable that its role increased at the later stages. The cause of important 87 Sr/ 86 Sr ratio variations in the rocks of one AIA petrographic type is the propylitization process with participation of sea water. Variance of 87 Sr/ 86 Sr ratios without taking into account other isotope systems data is not an indisputable proof of magma source heterogeneity

  10. Source Signature of Sr Isotopes in Fluids Emitting From Mud volcanoes in Taiwan

    Science.gov (United States)

    Chung, C.; You, C.; Chao, H.

    2003-12-01

    Located at the boundary between the Philippine Sea Plate and the Asia Continental Plate, abundance of mud volcanoes were erupted on land in Taiwan. According to their occurrences and associated tectonic settings, these mud volcanoes were classified into four groupies. The group (I) mud volcanoes are located in the western coastal plane, whereas group (II) and (III) are situated near the Kutinkung anticline axis and the Chishan fault respectively. The group (IV) mud volcanoes are discovered at the Coastal Range. Although there are numerous studies focused on morphology, possible fluid migration paths and sources are poorly understood. We have collected and analyzed major ions and Sr isotopic ratios in fluids separated from various mud volcanoes in Taiwan. Chemical contents of these fluids were measured by IC and the emitted gasses were analyzed by GC. The Sr concentrations in these fluids were determined using AA and the isotopic compositions were analyzed by TIMS. The dominated ions in fluids are Na and Cl which account for 98% of dissolved materials. All fluids show similar Na/Cl ratios(0.7-0.8), slightly higher than seawater but each group has unique Sr isotopic signature. Waters expelled from group I mud volcanoes featured with low salinity and high Sr isotopic ratios ranged from 0.71150 to 0.71175. Groups II and III were outcroped in the Kutinkung formation but show distinctive chemical compositions. Group II fluids have four times Cl concentrations(358-522mM) compared with those of group III(85-162mM). The latter fluids appear to be more radiogenic(0.71012- 0.71075) indicating possible influence due to water-rock interactions. Low 87Sr/86Sr(0.70692-0.70939) is typical characteristic of mud volcano fluids in group IV where large Mg and K depletion were discovered, suggesting effects due to sediment diagenetic processes. The chemical compositions of mud volcano associated gasses show similar distribution pattern. The major gas constituents in mud volcano zones

  11. Sr and Nd isotope geochemistry of coexisting alkaline magma series, Cantal, Massif Central, France

    International Nuclear Information System (INIS)

    Downes, H.

    1984-01-01

    Sr and Nd isotope analyses are presented for Tertiary continental alkaline volcanics from Cantal, Massif Central, France. The volcanics belong to two main magma series, silica-saturated and silica-undersaturated (with rare nephelinites). Trace element and isotopic data indicate a common source for the basic parental magmas of both major series; the nephelinites in contrast must have been derived from a mantle source which is isotopically and chemically distinct from that which gave rise to the basalts and basanites. 87 Sr/ 86 Sr initial ratios range from 0.7034 to 0.7056 in the main magma series (excluding rhyolites) and 143 Nd/ 144 Nd ratios vary between 0.512927 and 0.512669; both are correlated with increasing SiO 2 in the lavas. The data can be explained by a model of crustal contamination linked with fractional crystallisation. This indicates that crustal magma chambers are the sites of differentiation since only rarely do evolved magmas not show a crustal isotopic signature and conversely basic magmas have primitive isotopic ratios unless they contain obviuos crustal-derived xenocrysts. Potential contaminants include lower crustal granulites or partial melts of upper crustal units. Equal amounts of contamination are required for both magma series, refuting hypotheses of selective contamination of the silica-saturated series. The isotopic characteristics of the apparently primary nephelinite lavas demonstrates widespread heterogeneity in the mantle beneath Cantal. Some rhyolites, previously thought to be extremely contaminated or to be crustally derived, are shown to have undergone post-emplacement hydrothermal alteration. (orig.)

  12. Sr and Nd isotopes in basalts form the East Pacific Rise: Significance for mantle heterogeneity

    International Nuclear Information System (INIS)

    Macdougall, J.D.; Lugmair, G.W.

    1986-01-01

    Isotopic data for Sr and Nd from fresh glassy East Pacific Rise basalts suggest that this part of the suboceanic mantle is characterized by subtle but distinct large-scale regional isotopic variability which may reflect differences between cells of the convecting mantle. In spite of a systematic N-S change in spreading rate of a factor of three along the sampled portion of the EPR, no correlation is observed between spreading rate and range of isotopic composition, indicating that the regional variations override homogenization effects which may be correlated with rate of magma generation and hence spreading rate. There is no clear signature in our data of effects from the postulated global ''Dupal Anomaly''. However, for a restricted ridge segment at the latitude of Easter Island, anomalously high 87 Sr/ 86 Sr and low 143 Nd/ 144 Nd occur, coupled with high incompatible element concentrations. These features are most easily understood as being the result of inclusion of a ''plume'' component in these ridge basalts. (orig.)

  13. Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of $^{96}$Sr

    CERN Multimedia

    Clement, E; Siem, S; Czosnyka, T

    2007-01-01

    The nuclei in the mass region A $\\cong$ 100 around Sr and Zr show a dramatic change of the nuclear ground-state shape from near spherical for N $\\leq$ 58 to strongly deformed for N $\\geq$ 60. Theoretical calculations predict the coexistence of slightly oblate and strongly prolate deformed configurations in the transitional region. However, excited rotational structures based on the highly deformed configuration, which becomes the ground state at N = 60, are not firmly established in the lighter isotopes, and the earlier interpretation of a very abrupt change of shape has been challenged by recent experimental results in favor of a rather gradual change. We propose to study the electromagnetic properties of the neutron-rich nucleus $_{38}^{96}$Sr$_{58}$ by low-energy Coulomb excitation using the REX-ISOLDE facility and the MINIBALL detector array. Both transitional and diagonal matrix elements will be extracted, resulting in a complete description of the transition strengths and quadrupole moments of the low-l...

  14. Geographical variations in Sr and Nd isotopic ratios of cryoconite on Asian glaciers

    International Nuclear Information System (INIS)

    Nagatsuka, Naoko; Takeuchi, Nozomu; Nakano, Takanori; Shin, Kicheol; Kokado, Emi

    2014-01-01

    Cryoconite is a dark-coloured surface dust deposited on glaciers that consists of wind-blown mineral particles, as well as organic matter derived from microbes living on glaciers. In this paper, we analyse the Sr and Nd isotopic ratios of four mineral fractions (i.e., the saline, carbonate, phosphate, and silicate mineral fractions), as well as the organic fraction, of cryoconite samples obtained from six Asian glaciers (the Altai, Pamir, Tien Shan, Qillian Shan, and Himalayan regions), and discuss their geographical variations in terms of the geological origins of the mineral particles and the biogeochemical processes on the glaciers. The silicate mineral fraction showed lower Sr and higher Nd ratios for the glaciers located to the north (Altai, 87 Sr/ 86 Sr: 0.713 490–0.715 284, εNd(0): −6.4 to −5.6), while higher Sr and lower Nd ratios for the glaciers located to the south (Himalayas, 87 Sr/ 86 Sr: 0.740 121–0.742 088, εNd(0): −16.4 to −15.7); the ratios were similar to those of desert sand, loess, and river sediments in the respective regions of the glaciers. This result suggests that the silicate minerals within the cryoconites were derived from different sources depending on the geographical locations of the glaciers. The isotopic ratios of the saline, carbonate, and phosphate mineral fractions were distinct from those of the silicate fraction, and were similar to those of evaporites and apatite deposits from the Asian deserts, but also varied geographically, indicating that they are likely to reflect their geological origin. The Sr isotopic ratios of the organic fraction were similar to those of the saline and carbonate fractions from glaciers in the central area (Tien Shan and Qillian Shan), but were higher than those of the saline and carbonate fractions, and lower than the phosphate mineral fraction, in the northern and southern areas. The ratios of organic fraction may be determined from the mixing ratio of calcium sources

  15. The combined use of 87Sr/86Sr and carbon and water isotopes to study the hydrochemical interaction between groundwater and lakewater in mantled karst

    Science.gov (United States)

    Katz, Brian G.; Bullen, Thomas D.

    1996-12-01

    The hydrochemical interaction between groundwater and lakewater influences the composition of water that percolates downward from the surficial aquifer system through the underlying intermediate confining unit and recharges the Upper Floridan aquifer along highlands in Florida. The 87Sr/86Sr ratio along with the stable isotopes, D, 18O, and 13C were used as tracers to study the interaction between groundwater, lakewater, and aquifer minerals near Lake Barco, a seepage lake in the mantled karst terrane of northern Florida. Upgradient from the lake, the 87Sr/86Sr ratio of groundwater decreases with depth (mean values of 0.71004, 0.70890, and 0.70852 for water from the surficial aquifer system, intermediate confining unit, and Upper Floridan aquifer, respectively), resulting from the interaction of dilute oxygenated recharge water with aquifer minerals that are less radiogenic with depth. The concentrations of Sr2+ generally increase with depth, and higher concentrations of Sr2+ in water from the Upper Floridan aquifer (20-35 μg/L), relative to water from the surficial aquifer system and the intermediate confining unit, result from the dissolution of Sr-bearing calcite and dolomite in the Eocene limestone. Dissolution of calcite [δ13C= -1.6permil(‰)] is also indicated by an enriched δ13CDIC(-8.8 to -11.4 ‰) in water from the Upper Floridan aquifer, relative to the overlying hydrogeologic units (δ13CDICaquifer material become less radiogenic and the Sr2+ concentrations generally increase with depth. However, Sr2+ concentrations are substantially less than in upgradient groundwaters at similar depths. The lower Sr2+ concentrations result from the influence of anoxic lakewater leakage on the mobility of Sr2+ from clays. Based on results from mass-balance modeling, it is probable that cation exchange plays the dominant role in controlling the 87Sr/86Sr ratio of groundwater, both upgradient and downgradient from Lake Barco. Even though groundwater from the three

  16. Ca isotope fractionation and Sr/Ca partitioning associated with anhydrite formation at mid-ocean ridge hydrothermal systems: An experimental approach

    Science.gov (United States)

    Syverson, D. D.; Scheuermann, P.; Pester, N. J.; Higgins, J. A.; Seyfried, W. E., Jr.

    2016-12-01

    The elemental and isotopic mass balance of Ca and Sr between seawater and basalt at mid-ocean ridge (MOR) hydrothermal systems is an integrated reflection of the various physiochemical processes, which induce chemical exchange, in the subseafloor. Specifically, the processes of anhydrite precipitation and recrystallization are recognized to be important controls on governing the Ca and Sr elemental and isotope compositions of high temperature vent fluids, however, few experimental data exist to constrain these geochemical effects. Thus, to better understand the associated Sr/Ca partitioning and Ca isotope fractionation and rate of exchange between anhydrite and dissolved constituents, anhydrite precipitation and recrystallization experiments were performed at 175, 250, and 350°C and 500 bar at chemical conditions indicative of active MOR hydrothermal systems. The experimental data suggest that upon entrainment of seawater into MOR hydrothermal systems, anhydrite will precipitate rapidly and discriminate against the heavy isotopes of Ca (Δ44/40Ca(Anh-Fluid) = -0.68 - -0.25 ‰), whereas Sr/Ca partitioning depends on the saturation state of the evolving hydrothermal fluid with respect to anhydrite at each PTX (KD(Anh-Fluid) = 1.24 - 0.55). Coupling experimental constraints with the temperature gradient inferred for high temperature MOR hydrothermal systems in the oceanic crust, data suggest that the Ca isotope and Sr elemental composition of anhydrite formed near the seafloor will be influenced by disequilibrium effects, while, at higher temperatures further into the oceanic crust, anhydrite will be representative of equilibrium Sr/Ca partitioning and Ca isotope fractionation conditions. These experimental observations are consistent with analyzed Sr/Ca and Ca isotope compositions of anhydrites and vent fluids sampled from modern MOR hydrothermal systems1,2 and can be used to further constrain the geochemical effects of hydrothermal circulation in the oceanic crust

  17. Sr isotope zoning in plagioclase from andesites at Cabo De Gata, Spain: Evidence for shallow and deep contamination

    Science.gov (United States)

    Waight, Tod E.; Tørnqvist, Jakob B.

    2018-05-01

    Plagioclase crystals in andesites from the Cabo De Gata region show generally radiogenic Sr isotope compositions and consistent core to rim increases in 87Sr/86Sr that are indicative of open system processes in the lithosphere and crustal contamination during crystallization. High-grade metamorphic rocks of the Alpujárride and Nevado-Filábride complexes represent the most likely crustal contaminants. The plagioclases are characterized by subtly zoned and resorbed calcic cores (An73-86). These cores also have radiogenic 87Sr/86Sr (0.7127-0.7129), although typically less radiogenic than plagioclase rims, groundmass plagioclase and whole rock compositions (up to 87Sr/86Sr = 0.7135). These cores are interpreted to represent early crystallization of plagioclase from hydrous melts emplaced into the lower crust. The parental melts to these andesites must therefore have already inherited their radiogenic Sr isotope compositions prior to entering the lower crust and before the onset of crystallization of plagioclase, which is inconsistent with previous models suggesting that the generally radiogenic nature of Sr in these volcanics reflects large amounts of crustal contamination. Instead, the isotope systematics are consistent with models invoked significant addition of a subducted sediment component to the mantle source. The high-An% plagioclase cores are characterized by resorption textures, which are consistent with dissolution during rapid decompression and/or devolatisation during magma migration from the lower crust into upper crustal magma chambers.

  18. Trace-element and Sr-Nd isotopic evidence for the origin of the Sardinian fluorite mineralization (Italy)

    International Nuclear Information System (INIS)

    Castorina, F.; Masi, U.; Padalino, G.; Palomba, M.

    2008-01-01

    The fluorite-bearing hydrothermal mineralization in Sardinia mainly occurs within Paleozoic volcanic and metasedimentary rocks. Only 3 occurrences are located in volcanic and siliciclastic Cenozoic rocks. Most Sardinian fluorites exhibit relatively high rare earth and Y (REY) contents, strong positive Y anomalies, slightly negative Ce and generally positive Eu anomalies. These features indicate that the REY were mobilized mainly from non-carbonate rocks. Neither Sr nor Nd isotopes can be used to date radiometrically the Sardinian fluorites. However, the measured Sr-isotope ratios of the fluorites hosted by Paleozoic rocks fit mixing lines in the 1000/Sr versus 87 Sr/ 86 Sr plot once recalculated at 280 Ma, suggesting that the age inferred for the correction probably represents that of the formation of the fluorite mineralization. Mixing likely occurred between diluted surficial waters and brines circulating mainly through the Lower Paleozoic metasedimentary basement. The Cenozoic fluorites exhibit chemical and isotopic features similar to those of the Paleozoic fluorites, except the Nuraghe Onigu fluorite displaying a possible contribution of Sr from Cenozoic magmatic rocks. The initial ε Nd values of the Paleozoic fluorites fit the age proposed for the formation of the deposits. Moreover, the values suggest that radiogenic Nd was provided to the fluids from the Ordovician siliciclastic basement, except for 3 deposits where the potential source rocks of Nd were mainly Ordovician acidic magmatic rocks. The initial ε Nd values of the Cenozoic fluorites suggest a provenance of Nd essentially from the leaching of Variscan granitoids

  19. Use of Sr isotopes as a tool to decipher the soil weathering processes in a tropical river catchment, southwestern India

    International Nuclear Information System (INIS)

    Gurumurthy, G.P.; Balakrishna, K.; Tripti, M.; Riotte, Jean; Audry, Stéphane; Braun, Jean-Jacques; Udaya Shankar, H.N.

    2015-01-01

    River water composition (major ion and "8"7Sr/"8"6Sr ratio) was monitored on a monthly basis over a period of three years from a mountainous river (Nethravati River) of southwestern India. The total dissolved solid (TDS) concentration is relatively low (46 mg L"−"1) with silica being the dominant contributor. The basin is characterised by lower dissolved Sr concentration (avg. 150 nmol L"−"1), with radiogenic "8"7Sr/"8"6Sr isotopic ratios (avg. 0.72041 at outlet). The composition of Sr and "8"7Sr/"8"6Sr and their correlation with silicate derived cations in the river basin reveal that their dominant source is from the radiogenic silicate rock minerals. Their composition in the stream is controlled by a combination of physical and chemical weathering occurring in the basin. The molar ratio of SiO_2/Ca and "8"7Sr/"8"6Sr isotopic ratio show strong seasonal variation in the river water, i.e., low SiO_2/Ca ratio with radiogenic isotopes during non-monsoon and higher SiO_2/Ca with less radiogenic isotopes during monsoon season. Whereas, the seasonal variation of Rb/Sr ratio in the stream water is not significant suggesting that change in the mineral phase being involved in the weathering reaction could be unlikely for the observed molar SiO_2/Ca and "8"7Sr/"8"6Sr isotope variation in river water. Therefore, the shift in the stream water chemical composition could be attributed to contribution of ground water which is in contact with the bedrock (weathering front) during non-monsoon and weathering of secondary soil minerals in the regolith layer during monsoon. The secondary soil mineral weathering leads to limited silicate cation and enhanced silica fluxes in the Nethravati river basin. - Highlights: • Systematic monthly geochemical monitoring of a mountainous tropical river. • Soil weathering has dominant control on the surface water chemistry in the basin. • Soil redox process plays a dominant role in leaching of soil minerals. • Soil mineral weathering in

  20. New Rb-Sr isotopic ages and geochemistry of granitic gneisses from southern Bastar: implications for crustal evolution

    International Nuclear Information System (INIS)

    Sarkar, G.; Gupta, S.N.; Bishui, P.K.

    1994-01-01

    Deformed gneisses from the southern Bastar craton yield Rb-Sr whole-rock ages of 2560 Ma and 2659 Ma with initial Sr ratios ranging between 0.70899 and 0.70726 respectively. The isotopic data are found to be scattered even at the outcrop scale which possibly indicate large-scale reworking of the gneisses during the period. The high initial Sr ratios that associate with scattering of the isotopic data reflect reworking of older gneisses. Geochemically, these gneisses are considered to be derived from an amphibolitic or basaltic protolith. The 2095 Ma (initial Sr ratio of 0.74312) old leucocratic granite intrusive into these gneisses represent early Proterozoic magmatic activity. Based on the available isotopic and geochemical data, it is suggested that the Bastar craton represents a polyphase, multicomponent terrain developed by repeated magmatism at a much earlier, probably during mid-Archaean, time and was extensively reworked during the time span between end-Archaean and early Proterozoic period. This reworking may be synchronous with coalescing of smaller crustal components possibly during the end-Archaean time. (author). 21 refs., 5 figs., 2 tabs

  1. TIMS analysis of Sr and Nd isotopes in melt inclusions from Italian potassium-rich lavas using prototype 1013Ω amplifiers

    NARCIS (Netherlands)

    Koornneef, Janne M.; Nikogosian, Igor; van Bergen, Manfred J.; Smeets, Richard; Bouman, Claudia; Davies, Gareth R.

    2015-01-01

    Sr and Nd isotopes were determined using new thermal ionisation mass spectrometry (TIMS) techniques for a suite of 21 olivine-hosted (85-92mol% Fo) melt inclusions selected from potassic and ultra-potassic lavas from the Italian peninsula. Sr isotopes were measured using default 1011Ω resistors,

  2. Sr ISOTOPIC EVIDENCE FOR STUDYING THE SALINIZATION OF SOILS: AN EXAMPLE FROM THE SAN VITALE PINEWOOD (RAVENNA

    Directory of Open Access Journals (Sweden)

    Umberto Masi

    2009-12-01

    Full Text Available In the frame of a multidisciplinary project of research on the San Vitale Pinewood ecosystem, north of Ravenna, the Sr isotope study of a soil profile developed on an old coastal dune aiming at detecting the effect of salinization is presented. The Sr isotope ratios of the bulk soil samples decreased significantly from upper (0.717 to lower (0.712 horizons because of the abundant marine salts deposited by the brackish water present in the deep soil. While the main source of Sr in the upper horizons is the silicates, especially the feldspaths contained in the old dune sediments; in contrast, Sr in the lower horizons is significantly also of evaporitic origin (0.707-0.709. This latter is dominantly the strontium bio-available to the plants.

  3. Musa's granite and Rio Maria's granodiorite Rb/Sr isotopic ages and geochemistry

    International Nuclear Information System (INIS)

    Gastal, M.C.P.; Macambira, M.J.B.; Medeiros, H.; Dall'Agnol, R.

    1987-01-01

    The Musa Granite and the Rio Maria Granodiorite are located at the eastern margin of the Amazonian craton, in the Rio Maria region, where a typical granite-greenstone terrain is characterized. Rb-Sr dating of six samples from different facies of Rio Maria Granodiorite furnished an age of 2564 ± 68 Ma with initial 87 Sr/ 86 Sr radio (IR) of 0.70288 ± 0.00092 (whole rock isochron; 1 ο error; MSWD = 2.26). Thirteen samples from the three facies of Musa Granite (monzogranites, syenogranites and intermediate to felsic hypabyssal rocks) gave Rb-Sr whole rock isochron with an age of 1692 ± 11 Ma and IR of 0.70777 ± 0.00023 (1 ο error, MSWD = 1.89). A preliminary attempt to individualize geochronologically the three facies was done resulting different ages and IRs. There is a coincidence between these ages and the emplacement sequence of these facies of the pluton. The actual meaning of the Rio Maria Granodiorite Rb-Sr age is still uncertain. It could be related to the end of the magmatic crystallization of the batholith as well as to the metamorphic-mylonitic event that affect it. Considering that the Jamon and Musa Granites are petrologically similar that they occur in the same area, it is interesting to note that latter is apparently a little older than the former. The IRs obtained for the two plutons are also not coincident. The isotopic Rb-Sr available data show that the exposed rocks of the Rio Maria Granodiorite have not been able to generate magmas with the compositions of the monzongranitic and the hypabyssal facies of the Musa pluton. On the other hand, rocks isotopically similar to the Rio Maria Granodiorite would theorically be able to generate the Jamon and a magma with the characteristics of the syenogranitic facies of the Musa pluton. (author) [pt

  4. A compilation of Sr and Nd isotope data on Mexico

    International Nuclear Information System (INIS)

    Verma, S.P.; Verma, M.P.

    1986-01-01

    A compilation is given of the available Sr and Nd isotope data on Mexican volcanic-plutonic terranes which cover about one-third of Mexico's territory. The available data are arranged according to a subdivision of the Mexican territory in terms of geological provinces. Furthermore, site and province averages and standard deviations are calculated and their petrogenetic implications are pointed out. (author)

  5. The size-isotopic evolution connection among layered mafic instrusions: Clues from a Sr-Nd isotopic study of a small complex

    Science.gov (United States)

    Poitrasson, Franck; Pin, Christian; Duthou, Jean-Louis; Platevoet, Bernard

    1994-05-01

    Several theoretical and experimental works have focused on the processes occuring in continental mafic magma chambers. In contrast, systematic isotopic studies of natural remnants of these latter remain scarce, although they can give fundamental constraints for theoretical studies. This is especially true if different layered complex with contrasting characteristics (e.g., different size) are compared. For this reason, we present the results of a Sr-Nd isotopic profile across a small layered mafic intrusion of Permian age exposed near Fozzano (SW Corsica). In the main zone of the layered section, decreasing Sr-87/Sr(sub i)-86 and increasing Nd-143/Nd(sub i)-144 are observed from less evolved (bottom) to more evolved (top) rocks. This peculiar pattern precludes assimilation and fractional crystallization (AFC) as a dominant mechanism in the petrogenesis of this body. Instead, we interpret this trend as reflecting the dilution of an early stage contaminated magma by several reinjections of fresh basalt in the chamber. In agreement with mineralogical and structural data, every cyclic unit is interpreted as a new magmatic input. On the basis of rough refill and fractional crystallization (RFC) calculations, the average volume for each reinjection is estimated to have been about 0.04 cu km. The cumulative volume of these injections would amount to about 75% of the total volume of the layered complex. This implies that reinjections were accompanied by an important increase of the volume of the chamber or by magma withdrawal by surface eruptions. The RFC mechanism documented within this small layered body constrasts with the isotopic pattern observed between several intrusions at the regional scale in SW Corsica, and within large continental mafic magma chambers elsewhere. In these cases the isotopic evolution is dominated by AFC processes, and there is no clear isotopic evidence for reinjections, unless major influx of fresh magma occurred. It is suggested that there is

  6. The geographic distribution of Sr isotopes from surface waters and soil extracts over the island of Bornholm (Denmark) – A base for provenance studies in archaeology and agriculture

    DEFF Research Database (Denmark)

    Frei, Robert; Frei, Karin Margarita

    2013-01-01

    In this paper we report the Sr isotope signatures, and Sr, Al and Na concentrations of 30 surface waters (lakes/ponds and rivers/creeks) and 19 soil sample extracts from the island of Bornholm (Denmark) and present a categorized 87Sr/86Sr value distribution map that may serve as a base...... for provenance studies, including archaeological migration and authenticity proof for particular food products. The Sr isotopic compositions of surface waters range from 87Sr/86Sr = 0.7097–0.7281 (average 0.7175 ± 0.0049; 1σ), whereas 0.1 M HNO3, 0.05 M HNO3, and 0.01 M CaCl2 soil extracts range from 87Sr/86Sr...... Sr isotope composition vs. Sr, Na and Al concentration relationships of soil extracts imply that lowering of the isotopic composition of leachable Sr on Bornholm results as a consequence of significant admixture to this fraction of Sr deposited as marine salts (aerosols), and that rainwater only has...

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

    Science.gov (United States)

    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.

  8. A correlation of Sr isotope stratigraphy and foraminiferal biostratigraphy in tertiary limestones of Papua New Guinea

    International Nuclear Information System (INIS)

    Allan, T.L.; Trotter, J.A.; Whitford, D.J.; Korsch, M.J.

    2000-01-01

    Strontium isotopic and stratigraphic data collected from the Darai Limestone of Papua New Guinea clearly demonstrate a systematic relationship between bulk 87 Sr/ 86 Sr ratio and index foraminiferal composition that closely reflects the relative stratigraphical range of the foraminifera in this region. A graphic correlation of stratigraphic, strontium isotopic and age ranges of the major index taxa permits direct evaluation of limestone age and isotopic composition in the Darai Limestone. The age of the Tf 1 /Tf 2 boundary (∼12.2 Ma) is significantly younger than the accepted estimate of ∼15.0 Ma (plankton Zone N9) and the Te/Tf boundary (∼20.3 Ma) is older than the generally accepted age of ∼l 8.5 Ma (plankton Zone N6)

  9. S- and Sr-isotopic compositions in barite-silica chimney from the Franklin Seamount, Woodlark Basin, Papua New Guinea: constraints on genesis and temporal variability of hydrothermal fluid

    Science.gov (United States)

    Ray, Durbar; Banerjee, Ranadip; Balakrishnan, S.; Paropkari, Anil L.; Mukhopadhyay, Subir

    2017-07-01

    Isotopic ratios of strontium and sulfur in six layers across a horizontal section of a hydrothermal barite-silica chimney from Franklin Seamount of western Woodlark Basin have been investigated. Sr-isotopic ratios in barite samples (87Sr/86Sr = 0.70478-0.70493) are less radiogenic than seawater (87Sr/86Sr = 0.70917) indicating that substantial leaching of sub-seafloor magma was involved in the genesis of hydrothermal fluid. The SO2 of magma likely contributed a considerable amount of lighter S-isotope in fluid and responsible for the formation of barite, which is isotopically lighter (δ34S = 19.4-20.5 ‰) than modern seawater (δ34S 21 ‰). The systematic changes in isotopic compositions across the chimney wall suggest temporal changes in the mode of mineral formation during the growth of the chimney. Enrichment of heavy S- and Sr-isotopes (δ34S = 20.58 ‰; 87Sr/86Sr = 0.70493) in the outermost periphery of the chimney indicates that, at the initial stage of chimney development, there was a significant contribution of seawater sulfate during barite mineralization. Thereafter, thickening of chimney wall occurred due to precipitation of fluid carrying more magmatic components relative to seawater. This led to a gradual enrichment of lighter isotopes (δ34S = 20.42-19.48 ‰; 87Sr/86Sr = 0.70491-0.704787) toward the inner portion of the chimney wall. In contrast, the innermost layer surrounding the fluid conduit is characterized by heavier and more radiogenic isotopes (δ34S = 20.3 ‰; 87Sr/86Sr = 0.7049). This suggests there was increasing influence of percolating seawater on the mineral paragenesis at the waning phase of the chimney development.

  10. 87Sr/86Sr ratios in permo-carboniferous sea water from the analyses of well-preserved brachiopod shells

    International Nuclear Information System (INIS)

    Popp, B.N.; Anderson, T.F.

    1986-01-01

    Sr isotopic analyses of well-preserved portions of Permo-Carboniferous brachiopods distributed globally confirm the general shape of the Sr isotope age curve established by previous workers for this time interval. There is little variation between the SR isotopic composition of unaltered portions of brachiopods and that of portions of the same shell interpreted to be diagenetically altered (based on cathodoluminescence, elemental, and stable isotopic data). However, the Sr isotopic composition in diagenetically altered micritic matrix adjacent to the shell is more radiogenic. The Sr isotopic composition in the unaltered portions of calcitic megafossils has potential as a stratigraphic tool. (author)

  11. Nd and Sr isotopes and K-Ar ages of the Ulreungdo alkali volcanic rocks in the East Sea, South Korea

    International Nuclear Information System (INIS)

    Kim Kyuhan; Jang Sunkyung; Tanaka, Tsuyoshi; Nagao, Keisuke

    1999-01-01

    Temporal geochemical and isotopical variations in the Ulreundgo alkali volcanic rocks provide important constraints on the origin and evolution of the volcanic rocks in relation to backarc basin tectonism. We determined the K-Ar ages, major and trace element contents, and Nd and Sr isotopic rations of the alkali volcanic rocks. The activities of Ulreungdo volcanoes can be divided, on the basis of radiometric ages and field occurrences, into five stages, though their activities range from 1.4 Ma to 0.01 Ma with short volcanic hiatus (ca. 0.05-0.3 Ma). The Nd-Sr isotopic data for Ulreungdo volcanic rocks enable us to conclude that: (1) the source materials of Ulreungdo volcanics are isotopically heterogeneous in composition, which is explained by the mixing of mantle derived magma and continental crustal source rocks. There is no systematic isotopic variations with eruption stages. Particularly, some volcanic rocks of stage 2 and 3 have extremely wide initial 87 Sr/ 86 Sr isotopic variations ranging from 0.7038 to 0.7092, which are influenced by seawater alterations; (2) the Ulreungdo volcanic rocks show EMI characteristic, while volcanic rocks from the Jejudo, Yeong-il and Jeon-gok areas have slightly depleted mantle source characteristics; (3) the trachyandesite of the latest eruption stage was originated from the mantle source materials which differ from other stages. A schematic isotopic evolution model for alkali basaltic magma is presented in the Ulreungdo volcanic island of the backarc basin of Japanese island arc system. (author)

  12. Characterizing multiple sources and interaction in the critical zone through Sr-isotope tracing of surface and groundwater

    Science.gov (United States)

    Negrel, Philippe; Pauwels, Hélène

    2017-04-01

    The Critical Zone (CZ) is the lithosphere-atmosphere boundary where complex physical, chemical and biological processes occurs and control the transfer and storage of water and chemical elements. This is the place where life-sustaining resources are, where nutrients are being released from the rocks. Because it is the place where we are living, this is a fragile zone, a critical zone as a perturbed natural ecosystem. Water resources in hard-rocks commonly involve different hydrogeological compartments such as overlying sediments, weathered rock, the weathered-fissured zone, and fractured bedrock. Streams, lakes and wetlands that drain such environments can drain groundwater, recharge groundwater, or do both. Groundwater resources in many countries are increasingly threatened by growing demand, wasteful use, and contamination. Surface water and shallow groundwater are particularly vulnerable to pollution, while deeper resources are more protected from contamination. Here, we first report on Sr isotope data as well as major ions, from shallow and deep groundwater in several granite and schist areas over France with intensive agriculture covering large parts of these catchments. In three granite and Brioverian 'schist' areas of the Armorican Massif, the range in Sr contents in groundwater from different catchments agrees with previous work on groundwater sampled from granites in France. The Sr content is well correlated with Mg and both are partly related to agricultural practices and water rock interaction. The relationship between Sr- isotope and Mg/Sr ratios allow defining the different end-members, mainly rain, agricultural practice and water-rock interaction. The data from the Armorican Massif and other surface and groundwater for catchment draining silicate bedrocks (300-450Ma) like the Hérault, Seine, Moselle, Garonne, Morvan, Margeride, Cantal, Pyrénées and Vosges are scattered between at least three geochemical signatures. These include fertilizer and

  13. Nd and Sr isotopes and K-Ar ages of the Ulreungdo alkali volcanic rocks in the East Sea, South Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim Kyuhan; Jang Sunkyung [Ewha Womans Univ., Seoul (Korea); Tanaka, Tsuyoshi; Nagao, Keisuke

    1999-07-01

    Temporal geochemical and isotopical variations in the Ulreundgo alkali volcanic rocks provide important constraints on the origin and evolution of the volcanic rocks in relation to backarc basin tectonism. We determined the K-Ar ages, major and trace element contents, and Nd and Sr isotopic rations of the alkali volcanic rocks. The activities of Ulreungdo volcanoes can be divided, on the basis of radiometric ages and field occurrences, into five stages, though their activities range from 1.4 Ma to 0.01 Ma with short volcanic hiatus (ca. 0.05-0.3 Ma). The Nd-Sr isotopic data for Ulreungdo volcanic rocks enable us to conclude that: (1) the source materials of Ulreungdo volcanics are isotopically heterogeneous in composition, which is explained by the mixing of mantle derived magma and continental crustal source rocks. There is no systematic isotopic variations with eruption stages. Particularly, some volcanic rocks of stage 2 and 3 have extremely wide initial {sup 87}Sr/{sup 86}Sr isotopic variations ranging from 0.7038 to 0.7092, which are influenced by seawater alterations; (2) the Ulreungdo volcanic rocks show EMI characteristic, while volcanic rocks from the Jejudo, Yeong-il and Jeon-gok areas have slightly depleted mantle source characteristics; (3) the trachyandesite of the latest eruption stage was originated from the mantle source materials which differ from other stages. A schematic isotopic evolution model for alkali basaltic magma is presented in the Ulreungdo volcanic island of the backarc basin of Japanese island arc system. (author)

  14. Ground-state properties of axially deformed Sr isotopes in Skyrme-Hartree-Fock-Bogolyubov method

    International Nuclear Information System (INIS)

    Yilmaz, A.H.; Bayram, T.; Demirci, M.; Engin, B.; Bayram, T.

    2010-01-01

    Binding energies, the mean-square nuclear radii, neutron radii, quadrupole moments and deformation parameters to axially deformed Strontium isotopes were evaluated using Hartree-Fock-Bogolyubov method. Shape coexistence was also discussed. The results were compared with experimental data and some estimates obtained within some nuclear models. The calculations were performed for SIy4 set of Skyrme forces and for wide range of the neutron numbers of Sr isotopes

  15. Sources, migration and transformation of antimony contamination in the water environment of Xikuangshan, China: Evidence from geochemical and stable isotope (S, Sr) signatures

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Bing [Geological Survey, China University of Geosciences (Wuhan), Lumo Rd 388, Wuhan 430074, Hubei (China); State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Lumo Rd 388, Wuhan 430074, Hubei (China); Zhou, Jianwei, E-mail: jw.zhou@cug.edu.cn [School of Environmental Studies, China University of Geosciences (Wuhan), Lumo Rd 388, Wuhan 430074, Hubei (China); Zhou, Aiguo; Liu, Cunfu [School of Environmental Studies, China University of Geosciences (Wuhan), Lumo Rd 388, Wuhan 430074, Hubei (China); Xie, Lina [School of Environmental Studies, China University of Geosciences (Wuhan), Lumo Rd 388, Wuhan 430074, Hubei (China); State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Lumo Rd 388, Wuhan 430074, Hubei (China)

    2016-11-01

    The Xikuangshan (XKS) mine in central China is the largest antimony (Sb) mine in the world. The mining activity has seriously contaminated the waters in the area. To determine the sources, migration and transformation of Sb contamination, 32 samples from groundwater (aquifer water), surface water and mine water were collected for water chemistry, trace element and S{sub SO4} and Sr stable isotope analyses. The results showed that the groundwater and surface water were in an oxidized environment. The S{sub SO4} and Sr isotope compositions in the water indicated that dissolved Sb and SO{sub 4}{sup 2} originated from sulfide mineral (Sb{sub 2}S{sub 3}) oxidation, whereas radiogenic Sr may have been sourced from silicified limestone and stibnite in the Shetianqiao aquifer. Furthermore, a positive correlation between δ{sup 34}S{sub SO4} and δ{sup 87}Sr values revealed that the Sr, S and Sb in the waters had a common contamination source, i.e., silicified limestone and stibnite, whereas the Sr, S and Sb in rock and ore were sourced from Proterozoic basement clastics. The analysis also indicated that the isotope composition of dissolved SO{sub 4}{sup 2} {sup −} had been influenced by slight bacterial SO{sub 4} reduction in the Magunao aquifer. Mining or rock collapse may have caused Shetianqiao aquifer water to contaminate the Magunao aquifer water via mixing. This study has demonstrated that the stable isotopes of {sup 34}S{sub SO4} and {sup 87}Sr, combined with hydrochemical methods, are effective in tracking the sources, migration and transformation of Sb contamination. - Highlights: • Mining activities at XKS mine have caused serious water contamination. • The characteristics of Sb contamination in water environment are still unclear. • Combine S isotopes of sulfate and Sr isotopes with hydrochemical methods. • Sr, S, and Sb in natural water had a common source: silicified limestone and stibnite. • Shetianqiao aquifer water contaminated the Magunao

  16. Sources, migration and transformation of antimony contamination in the water environment of Xikuangshan, China: Evidence from geochemical and stable isotope (S, Sr) signatures

    International Nuclear Information System (INIS)

    Wen, Bing; Zhou, Jianwei; Zhou, Aiguo; Liu, Cunfu; Xie, Lina

    2016-01-01

    The Xikuangshan (XKS) mine in central China is the largest antimony (Sb) mine in the world. The mining activity has seriously contaminated the waters in the area. To determine the sources, migration and transformation of Sb contamination, 32 samples from groundwater (aquifer water), surface water and mine water were collected for water chemistry, trace element and S_S_O_4 and Sr stable isotope analyses. The results showed that the groundwater and surface water were in an oxidized environment. The S_S_O_4 and Sr isotope compositions in the water indicated that dissolved Sb and SO_4"2 originated from sulfide mineral (Sb_2S_3) oxidation, whereas radiogenic Sr may have been sourced from silicified limestone and stibnite in the Shetianqiao aquifer. Furthermore, a positive correlation between δ"3"4S_S_O_4 and δ"8"7Sr values revealed that the Sr, S and Sb in the waters had a common contamination source, i.e., silicified limestone and stibnite, whereas the Sr, S and Sb in rock and ore were sourced from Proterozoic basement clastics. The analysis also indicated that the isotope composition of dissolved SO_4"2 "− had been influenced by slight bacterial SO_4 reduction in the Magunao aquifer. Mining or rock collapse may have caused Shetianqiao aquifer water to contaminate the Magunao aquifer water via mixing. This study has demonstrated that the stable isotopes of "3"4S_S_O_4 and "8"7Sr, combined with hydrochemical methods, are effective in tracking the sources, migration and transformation of Sb contamination. - Highlights: • Mining activities at XKS mine have caused serious water contamination. • The characteristics of Sb contamination in water environment are still unclear. • Combine S isotopes of sulfate and Sr isotopes with hydrochemical methods. • Sr, S, and Sb in natural water had a common source: silicified limestone and stibnite. • Shetianqiao aquifer water contaminated the Magunao aquifer water via mixing.

  17. Pb and Sr isotopic systematics of some basalts and sulfides from the East Pacific Rise at 210N (project RITA)

    International Nuclear Information System (INIS)

    Vidal, P.; Clauer, N.

    1981-01-01

    Tholeiitic basalts and sulfide deposits from the 'Cyana' and 'Alvin' diving programs (RITA project) on the East Pacific Rise were analyzed for Pb and Sr isotopes. The basalt data plot within the field defined previously by other East Pacific Rise basalts ( 206 Pb/ 204 Pb: 18.35-18.58; 207 Pb/ 204 Pb: 15.48-15.53; 208 Pb/ 204 Pb: 37.8-38.1; 87 Sr/ 86 Sr: 0.7022-0.7025). Pb, U and Sr contents (approx. equal to 0.5, approx. equal to 0.05 and approx. equal to 110 ppm, respectively) and μ values (approx. equal to 6) are typical of MORB, whereas Th/U ratios (approx. equal to 3.5) are significantly higher. The Pb isotopic ratios of the sulfide samples are very homogeneous ( 206 Pb/ 204 Pb approx. equal to 18.47, 207 Pb/ 204 Pb approx. equal to 15.49, 208 Pb/ 204 Pb approx. equal to 37.90), and plot in the middle of the basalt field. This indicates that the sulfide Pb was derived from the basaltic crust without any significant contribution from either seawater or hemipelagic sediments, and the solutions from which the sulfiedes were deposited had uniform Pb isotopic composition. The Pb contents of three sulfide samples is relatively high (170-1310 ppm). The Sr contents of five sulfide samples are widely scattered from 12 to 210 ppm, with 87 Sr/ 86 Sr ratios intermediate between basaltic and seawater values (0.70554 +- 0.00005 to 0.70795 +- 0.00011). Leaching experiments show that both basalt-derived Sr and seawater Sr were present in the solutions which deposited the sulfides. In some cases, Sr was also adsorbed from seawater onto the sulfides following their deposition. Basalt-derived Sr and seawater Sr are also present in associated non-sulfide phases. (orig.)

  18. Clay mineralogical and Sr, Nd isotopic investigations in two deep-sea sediment cores from Northeast Indian Ocean

    International Nuclear Information System (INIS)

    Anil Babu, G.; Masood Ahmad, S.; Padmakumari, V.M.; Dayal, A.M.

    2004-01-01

    Sr and Nd isotopic studies in terrigenous component of the ocean sediments provide useful information about weathering patterns near source rock and climatic conditions existed on the continents. Variations in 87 Sr/ 86 Sr and 143 Nd/ 144 Nd isotopic ratios in clastic sediments depend on the source from the continents, volcanic input and circulation changes. The composition of clay minerals mainly depends on climate, geology and topography of the surrounding region. Chlorite and Illite are formed under physical weathering in arid cold climate and kaolinite and smectite are the characteristic products of chemical weathering in humid wet climatic conditions. Therefore, the variations in clay mineral composition in deep-sea sediments can be interpreted in terms of changes in the climatic conditions prevailed in the continental source areas

  19. Sr isotope characterization of atmospheric inputs to soils along a climate gradient of the Chilean Coastal Range

    Science.gov (United States)

    Oeser, Ralf; Schuessler, Jan A.; Floor, Geerke H.; von Blanckenburg, Friedhelm

    2017-04-01

    The rate and degree of rock weathering controls the release, distribution, and cycling of mineral nutrients at the Earth's surface, being essential for developing and sustaining of ecosystems. Climate plays an important role as water flow and temperature determine both the biological community and activity, and also set the speed of weathering. Because of this double control by climate, the impact of biological activity on rock weathering and the feedbacks between the geosphere and the biosphere under different climatic conditions are not well understood. We explore the impact of biota on rock weathering in the four EarthShape primary study areas which are situated along the Chilean Coastal Range, featuring an outstanding vegetation gradient controlled by climate, ranging over 2000 km from hyper-arid, to temperate, to humid conditions. The study sites are within 80 km of the Pacific coast and are located in granitic lithology. Moreover, the sites were unglaciated during the last glacial maximum. However, as substrates get depleted in mineral nutrients, ecosystems are increasingly nourished by atmospheric inputs, sources, such as solutes contained in rain, dust, and volcanic ash. We aim to quantify the primary nutrient inputs to the ecosystem from these different potential sources. Radiogenic strontium (Sr) isotope ratios are a powerful tool to trace chemical weathering, soil formation, as well as cation provenance and mobility [1]. We determined 87Sr/86Sr ratios on bulk bedrock, saprolite, and soil and performed sequential extractions of the the easily bioavailable soil phases up to 2 m depth on two soil depth profiles in each of the four study sites. Our first results from the La Campana study site indicate that the radiogenic Sr isotope ratios of saprolite samples decrease from 0.70571 (n = 4) at the base of the profile to lower values of 0.70520 (n = 4) at the top of the immobile saprolite, indicating increasing biotite weathering. 87Sr/86Sr increases in the

  20. Ash layer at ∼ 8 Ma in ODP site 758 from the Bay of Bengal: evidence from Sr, Nd isotopic compositions and rare earth elements

    International Nuclear Information System (INIS)

    Padmakumari, V.M.; Ahmad, S.M.

    2004-01-01

    Strontium and neodymium isotopic compositions are widely used to delineate the provenance of sedimentary formations. These isotopes have characteristic signatures for crust and mantle material and therefore can distinguish between volcanic and other rock types. 87 Sr/ 86 Sr. ε Nd (0) and rare earth elements REE of clay sediments from ODP site 758 in the Bay of Bengal is reported here. Our results clearly show that Sr and Nd isotopes can identify thin ash layers that otherwise may not easily be recognized

  1. Sr isotopes at Copahue Volcanic Center, Neuquen, Argentina: Preliminary report

    International Nuclear Information System (INIS)

    Linares, E.; Ostera, H.A.; Cagnoni, M.C

    2001-01-01

    The Copahue Volcanic Center is located in the Cordillera Principal, at 38 L.S., in the Argentina- Chilean border. Detailed geological, geochronological and structural studies were carried out during the last decade (Pesce, 1989; Delpino y Bermudez, 1993; Linares et al., 1995, 1999; Folguera y Ramos, 2000; among others). We present Sr isotopes data on the main units of the Volcanic Center, coupled with a major element geochemistry, to constrain the evolution of the volcanic center (au)

  2. Derivation of Apollo 14 High-Al Basalts at Discrete Times: Rb-Sr Isotopic Constraints

    Science.gov (United States)

    Hui, H.; Neal, C. R.; Shih, C.-Y.; Nyquist, L. E.

    2012-03-01

    Four eruption episodes were identified for A-14 high-Al basalts. Rb-Sr isotopic data and ITE ratios show that their parental melt compositions of are correlated through mixing of evolved components with a relatively primitive magma ocean cumulate.

  3. Sr and Nd isotope composition of the metamorphic, sedimentary and ultramafic xenoliths of Lanzarote (Canary Islands): Implications for magma sources

    Science.gov (United States)

    Aparicio, Alfredo; Tassinari, Colombo C. G.; García, Roberto; Araña, Vicente

    2010-01-01

    The lavas produced by the Timanfaya eruption of 1730-1736 (Lanzarote, Canary Islands) contain a great many sedimentary and metamorphic (metasedimentary), and mafic and ultramafic plutonic xenoliths. Among the metamorphosed carbonate rocks (calc-silicate rocks [CSRs]) are monomineral rocks with forsterite or wollastonite, as well as rocks containing olivine ± orthopyroxene ± clinopyroxene ± plagioclase; their mineralogical compositions are identical to those of the mafic (gabbros) and ultramafic (dunite, wherlite and lherzolite) xenoliths. The 87Sr/ 86Sr (around 0.703) and 143Nd/ 144Nd (around 0.512) isotope ratios of the ultramafic and metasedimentary xenoliths are similar, while the 147Sm/ 144Nd ratios show crustal values (0.13-0.16) in the ultramafic xenoliths and mantle values (0.18-0.25) in some CSRs. The apparent isotopic anomaly of the metamorphic xenoliths can be explained in terms of the heat source (basaltic intrusion) inducing strong isotopic exchange ( 87Sr/ 86Sr and 143Nd/ 144Nd) between metasedimentary and basaltic rocks. Petrofabric analysis also showed a possible relationship between the ultramafic and metamorphic xenoliths.

  4. Improvements in Precise and Accurate Isotope Ratio Determination via LA-MC-ICP-MS by Application of an Alternative Data Reduction Protocol

    Science.gov (United States)

    Fietzke, J.; Liebetrau, V.; Guenther, D.; Frische, M.; Zumholz, K.; Hansteen, T. H.; Eisenhauer, A.

    2008-12-01

    An alternative approach for the evaluation of isotope ratio data using LA-MC-ICP-MS will be presented. In contrast to previously applied methods it is based on the simultaneous responses of all analyte isotopes of interest and the relevant interferences without performing a conventional background correction. Significant improvements in precision and accuracy can be achieved when applying this new method and will be discussed based on the results of two first methodical applications: a) radiogenic and stable Sr isotopes in carbonates b) stable chlorine isotopes of pyrohydrolytic extracts. In carbonates an external reproducibility of the 87Sr/86Sr ratios of about 19 ppm (RSD) was achieved, an improvement of about a factor of 5. For recent and sub-recent marine carbonates a mean radiogenic strontium isotope ratio 87Sr/86Sr of 0.709170±0.000007 (2SE) was determined, which agrees well with the value of 0.7091741±0.0000024 (2SE) reported for modern sea water [1,2]. Stable chlorine isotope ratios were determined ablating pyrohydrolytic extracts with a reproducibility of about 0.05‰ (RSD). For basaltic reference material JB1a and JB2 chlorine isotope ratios were determined relative to SMOC (standard mean ocean chlorinity) δ37ClJB-1a = (-0.99±0.06) ‰ and δ37ClJB-1a = (-0.60±0.03) ‰ (SD), respectively, in accordance with published data [3]. The described strategies for data reduction are considered to be generally applicable for all isotope ratio measurements using LA-MC-ICP-MS. [1] J.M. McArthur, D. Rio, F. Massari, D. Castradori, T.R. Bailey, M. Thirlwall, S. Houghton, Palaeogeo. Palaeoclim. Palaeoeco., 2006, 242 (126), doi: 10.1016/j.palaeo.2006.06.004 [2] J. Fietzke, V. Liebetrau, D. Guenther, K. Guers, K. Hametner, K. Zumholz, T.H. Hansteen and A. Eisenhauer, J. Anal. At. Spectrom., 2008, 23, 955-961, doi:10.1039/B717706B [3] J. Fietzke, M. Frische, T.H. Hansteen and A. Eisenhauer, J. Anal. At. Spectrom., 2008, 23, 769-772, doi:10.1039/B718597A

  5. Sr isotope geochemistry of East Alpine mineral deposits and mass spectrometric analyses of fluid inclusions

    International Nuclear Information System (INIS)

    Grum, W.

    1995-05-01

    Strontium isotope geochemistry and deformational history of selected carbonate-hosted deposits from different tectonic positions in the Eastern Alps were studied. In this context an equipment has been constructed to analyze the composition of volatile components of fluid inclusions (FI). Based on the results of Sr-isotopic investigations two groups of deposits are discriminated: Deposits formed by formation waters and/or metamorphogenic fluids: Tux (magnesite, scheelite), Otterzug (barite), Lassing (magnesite), Rabenwald (talc), Laussa and Mooseck (fluorite). The mineralizing fluids are derived from different sedimentary rock series and therefore 87 Sr/ 86 Sr-ratios vary between 0.707 and 0.719. Deposits situated along fault zones: Lassing (talc), Gasteiner Tal (Silberpfennig area; gold), Schlaining (stibnite) and Waldenstein (specularite). Sr isotope ratios of the mineralizing fluids from Lassing, Waldenstein and Schlaining ranges from 0.7112 to 0.7127 and are therefore thought to have scavenged the East Alpine crystalline. The mineralizing solutions of the Gasteiner Tal deposit may either have equilibrated with low radiogenic sedimentary or with (ultra-)basic rocks. A cracking chamber has been constructed in order to open FI by cracking for mass spectrometric analysis of volatile components. Gases are analysed using a quadrupole mass spectrometer. The desorption of gas from metal and sample surfaces during cracking can be neglected. The amount of gas released from the mineral lattices was studied. With that fast method ore bearing from barren host rocks have been distinguished by different composition of the FI at the Brixlegg barite mineralization (Eastern Alps). Within the Galway fluorite deposit (Ireland) different fluids were involved and mass spectrometric analysis were carried out to characterize these different fluids and to identify their origin. (author)

  6. Groundwater in the Broken Hill region, Australia: recognising interaction with bedrock and mineralisation using S, Sr and Pb isotopes

    International Nuclear Information System (INIS)

    Caritat, Patrice de; Kirste, Dirk; Carr, Graham; McCulloch, Malcolm

    2005-01-01

    The supergiant Pb-Zn-Ag Broken Hill orebody and numerous other minor mineral deposits occur within the limited outcrop of the Proterozoic Curnamona Province of Australia. The vast majority of this Province is concealed by up to 200 m of transported regolith, hampering conventional exploration strategies. Approximately 300 groundwater samples were collected over the southern Curnamona Province to test whether this medium could be helpful in the search for hidden mineral deposits. Sulphur, Sr and Pb isotope composition of the groundwaters were determined and S excess (S XS ), i.e., the amount of S that can be ascribed neither to evaporation nor to mixing, was calculated. Many samples were recognised to have undergone an addition of 34 S-depleted S, which can be attributed to oxidation of sulfides with a Broken Hill type δ 34 S signature (average ∼0%o V-CDT). Furthermore, Sr isotopes identify the broad types of bedrock that the groundwater has been interacting with, from the less radiogenic Adelaidean rocks (and minerals) in the west (groundwater 87 Sr/ 86 Sr ratio as low as 0.708) to the highly radiogenic Willyama Supergroup in the east ( 87 Sr/ 86 Sr ratio up to 0.737). The groundwaters have 207 Pb/ 204 Pb and 206 Pb/ 204 Pb ratios comparable to, or intermediate between, various mineralisation types recognised in the area (Broken Hill, Rupee, Thackaringa, etc., types). The few samples taken in the vicinity of known mineralisation yield positive indicators (positive S XS , low δ 34 S, 87 Sr/ 86 Sr signature of bedrock type and Pb isotope fingerprinting of mineralisation type). This study also highlights several new locations under sedimentary cover where these indicators suggest interaction with mineralisation

  7. Petrochemical and Sr-Nd isotope investigations of Cretaceous intrusive rocks and their enclaves in the Togouchi-Yoshiwa district, northwest Hiroshima prefecture, SW Japan

    International Nuclear Information System (INIS)

    Ishioka, Jun; Iizumi, Shigeru

    2003-01-01

    Petrographic, petrochemical and Sr-Nd isotopic data are presented for granitoids and microdioritic enclaves from two Cretaceous stocks (Togouchi granodiorite and Tateiwayama granite porphyry) from the Togouchi-Yoshiwa district, northwest Hiroshima prefecture, SW Japan. The data are used to examine the genetic relationships between the microdioritic enclaves and their granitoid hosts. The granodiorite, granite porphyry and the microdioritic enclaves are all calc-alkaline in nature, and belong to the I-type ilmenite series. The Togouchi graniodiorite has a Rb-Sr whole rock isochron age of 85.6±4.7 Ma with an initial Sr isotope ratio (SrI) of 0.70634±0.00012 (2σ). The Tateiwayama granite porphyry has a slightly younger Rb-Sr whole isochron age (77.4±3.1 Ma) but similar SrI of 0.70653±0.00015, suggesting that both stocks may have been derived from the same source. Despite diverse whole rock chemistry, the microdioritic enclaves in the respective intrusives have quite similar initial Sr and Nd isotope ratios, suggesting that they formed by fractional crystallization of a single magma, and also that the source of the enclaves in both intrusives had similar geochemical characteristics. In both stocks, however, the enclaves have distinctly lower initial Sr isotope ratios than their respective host rocks, indicating that they were derived from a different source than their hosts. In view of the geochemical and Sr-Nd isotope data, we infer that the enclave magmas were derived from a similar LILE- and LREE-enriched source to that of the Cretaceous basalts and gabbroic-dioritic rocks that are sporadically distributed in SW Japan. Such mafic to intermediate magmas were probably derived from the upper mantle, and transferred both heat and material to the lower crust, thus producing granitic magmas by partial melting. Successive mafic magmas or their differentiates could then have been injected into the granitic magma chamber, trapped and quenched, resulting in the formation

  8. Interaction between different groundwaters in brittany catchments (france): characterizing multiple sources through Sr- and S isotope tracing

    Science.gov (United States)

    Negrel, Ph; Pauwels, H.

    2003-04-01

    Water resources in hard-rocks commonly involve different hydrogeological compartments such as overlying sediments, weathered rock, the weathered-fissured zone, and fractured bedrock. Streams, lakes and wetlands that drain such environments can drain groundwater, recharge groundwater, or do both. Groundwater resources in many countries are increasingly threatened by growing demand, wasteful use, and contamination. Surface water and shallow groundwater are particularly vulnerable to pollution, while deeper resources are more protected from contamination. Sr- and S-isotope data as well as major ions, from shallow and deep groundwater in three granite and Brioverian "schist" areas of the Armorican Massif (NW France) with intensive agriculture covering large parts are presented. The stable-isotope signatures of the waters plot close to the general meteoric-water line, reflecting a meteoric origin and the lack of significant evaporation or water-rock interaction. The water chemistry from the different catchments shows large variation in the major-element contents. Plotting Na, Mg, NO_3, K, SO_4 and Sr vs. Cl contents concentrations reflect agricultural input from hog and livestock farming and fertilizer applications, with local sewage-effluent influence, although some water samples are clearly unpolluted. The δ34S(SO_4) is controlled by several potential sources (atmospheric sulphate, pyrite-derived sulphates, fertilizer sulphates). Some δ18O and δ34S values are expected to increase through sulphate reduction, with higher effect on δ34S for the dissimilatory processes and on δ18O for assimilatory processes. The range in Sr contents in groundwater from different catchments agrees with previous work on groundwater sampled from granites in France. The Sr content is well correlated with Mg and both are related to agricultural practises. As in granite-gneiss watersheds in France, 87Sr/86Sr ratios range from 0.71265 to 0.72009. The relationship between 87Sr/86Sr and Mg/Sr

  9. Coral Sr-U Thermometry

    Science.gov (United States)

    DeCarlo, T. M.; Gaetani, G. A.; Cohen, A. L.; Foster, G. L.; Alpert, A.; Stewart, J.

    2016-12-01

    Coral skeletons archive the past two millennia of climate variability in the oceans with unrivaled temporal resolution. However, extracting accurate temperature information from coral skeletons is confounded by "vital effects", which often override the temperature dependence of geochemical proxies. Here, we present a new approach to coral paleothermometry based on results of abiogenic precipitation experiments interpreted within a framework provided by a quantitative model of the coral biomineralization process. We conducted laboratory experiments to test the temperature and carbonate chemistry controls on abiogenic partitioning of Sr/Ca and U/Ca between aragonite and seawater, and we modeled the sensitivity of skeletal composition to processes occurring at the site of calcification. The model predicts that temperature can be accurately reconstructed from coral skeleton by combining Sr/Ca and U/Ca ratios into a new proxy, Sr-U. We tested the model predictions with measured Sr/Ca and U/Ca ratios of fourteen Porites sp. corals collected from the tropical Pacific Ocean and the Red Sea, with a subset also analyzed using the boron isotope (δ11B) pH proxy. Observed relationships among Sr/Ca, U/Ca, and δ11B agree with model predictions, indicating that the model accounts for the key features of the coral biomineralization process. We calibrated Sr-U to instrumental temperature records and found that it captures 93% of mean annual variability (26-30 °C) and predicts temperature within 0.5 °C (1 σ). Conversely, Sr/Ca alone has an error of prediction of 1 °C and often diverges from observed temperature by 3 °C or more. Many of the problems afflicting Sr/Ca - including offsets among neighboring corals and decouplings from temperature during coral stress events - are reconciled by Sr-U. By accounting for the influence of the coral biomineralization process, the Sr-U thermometer may offer significantly improved reliability for reconstructing ocean temperatures from coral

  10. Input of 87Sr/86Sr ratios and Sr geochemical signatures to update knowledge on thermal and mineral waters flow paths in fractured rocks (N-Portugal)

    International Nuclear Information System (INIS)

    Marques, J.M.; Carreira, P.M.; Goff, F.; Eggenkamp, H.G.M.; Antunes da Silva, M.

    2012-01-01

    Strontium isotopes and other geochemical signatures are used to determine the relationships between CO 2 -rich thermal (Chaves: 76 °C) and mineral (Vilarelho da Raia, Vidago and Pedras Salgadas: 17 °C) waters discharging along one of the major NNE–SSW trending faults in the northern part of mainland Portugal. The regional geology consists of Hercynian granites (syn-tectonic-310 Ma and post-tectonic-290 Ma) intruding Silurian metasediments (quartzites, phyllites and carbonaceous slates). Thermal and mineral waters have 87 Sr/ 86 Sr isotopic ratios between 0.716713 and 0.728035. 87 Sr/ 86 Sr vs. 1/Sr define three end-members (Vilarelho da Raia/Chaves, Vidago and Pedras Salgadas thermal and mineral waters) trending from rainfall composition towards that of the CO 2 -rich thermal and mineral waters, indicating different underground flow paths. Local granitic rocks have 87 Sr/ 86 Sr ratios of 0.735697–0.789683. There is no indication that equilibrium was reached between the CO 2 -rich thermal and mineral waters and the granitic rocks. The mean 87 Sr/ 86 Sr ratio of the thermal and mineral waters (0.722419) is similar to the Sr isotopic ratios of the plagioclases of the granitic rocks (0.71261–0.72087). The spatial distribution of Sr isotope and geochemical signatures of waters and the host rocks suggests that the thermal and mineral waters circulate in similar but not the same hydrogeological system. Results from this study could be used to evaluate the applicability of this isotope approach in other hydrogeologic investigations.

  11. Sr isotope variations in the Carnian-Norian succession at Pizzo Mondello, Sicani Mountains, Sicily

    Science.gov (United States)

    Onoue, T.; Yamashita, K.; Rigo, M.; Abate, B.

    2017-12-01

    The Norian stage in the Late Triassic is exceptionally long (23 Myr) and was subdivided into three substages: the Lacian, Alaunian, and Sevatian. In order to infer the Norian environmental changes in the western Tethys Ocean, the stratigraphic variations of 87Sr/86Sr in the Upper Triassic limestone succession in Sicily were examined. The Pizzo Mondello section studied here mainly consists of a pelagic carbonate sequence of the Scillato Formation, and ranges in age from Tuvalian (late Carnian) to Rhaetian. The Scillato Formation represents a deep-water pelagic facies deposited along the Sicanian Basin in the western Tethys Ocean. We selected fine-grained limestone samples from both the microfacies of lime-mudstone and wackestone to approximate the primary 87Sr/86Sr signature of the limestone beds. The 87Sr/86Sr values are relatively constant in the Tuvalian and Lacian (early Norian). However, the remarkable rise in 87Sr/86Sr occurred across the Lacian-Alaunian (early-middle Norian) transition. Variations in 87Sr/86Sr values show an increasing trend in 87Sr/86Sr from 0.7077 at the base of Lacian to 0.7080 in the Sevatian (late Norian). In the Sevatian, the 87Sr/86Sr ratios display a sudden negative excursion toward lower values and show a relatively quick recovery to pre-excursion 87Sr/86Sr ratios. Korte et al. (2003) suggested that the rise in the 87Sr/86Sr values from the middle Carnian to the late Norian coincide with the Cimmerian orogeny. Our new 87Sr/86Sr data from the Pizzo Mondello section reveal a comparable trend, with a sharp increase in 87Sr/86Sr within the Alaunian, suggesting the rapid uplift and erosion in the Cimmerian Mountains at this time. The cause of the 87Sr/86Sr excursion in the Sevatian remains uncertain. However, the biostratigraphic record of conodonts suggests that a morphological evolution towards platform-less elements occurred with the beginning of the Sr-isotope excursion.

  12. Use of the 87Sr/86Sr isotopic ratio as an environmental tracer: an example of the application to the Fossil Forest of the Dunarobba (FFD) sedimentary system near Aviglano Umbro (Terni-Central Italy)

    International Nuclear Information System (INIS)

    Barbieri, M.

    2002-01-01

    A recent discovery of Pliocene tree trunks (Taxodium, Glyptostrobus or Sequoia) perfectly preserved in the fluvial lacustrine sediments deposited in the old Tiberin Lake (near the town of Dunarobba, Central Italy) has led to the study of the conditions responsible for the trunks preservation. The present work has applied Sr isotope techniques to examine and confirm fluid migration in the different sediment types which cross the entire fluvial-lacustrine sequence. Based on the 87 Sr/ 86 Sr ratios measured in carbonate and in silicate fractions of samples collected from a bore hole (from 0 to 120 m) it is concluded that each sedimentary level has limited communication between zones and is characterised by different isotope values. This suggests that the intrinsic properties of these clays make them a good material for isolating waste, both for direct use and for a better buffer in other formations, possibly less secure, such as salt or granite. The results obtained in the present work have demonstrated some of the potential uses of the 87 Sr/ 86 Sr isotopic ratio as an environmental tracer for confirming results from some of the geotechnical (such as permeability) and geochemical parameters of these host sediments

  13. Precise and accurate isotope ratio measurements by ICP-MS.

    Science.gov (United States)

    Becker, J S; Dietze, H J

    2000-09-01

    The precise and accurate determination of isotope ratios by inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) is important for quite different application fields (e.g. for isotope ratio measurements of stable isotopes in nature, especially for the investigation of isotope variation in nature or age dating, for determining isotope ratios of radiogenic elements in the nuclear industry, quality assurance of fuel material, for reprocessing plants, nuclear material accounting and radioactive waste control, for tracer experiments using stable isotopes or long-lived radionuclides in biological or medical studies). Thermal ionization mass spectrometry (TIMS), which used to be the dominant analytical technique for precise isotope ratio measurements, is being increasingly replaced for isotope ratio measurements by ICP-MS due to its excellent sensitivity, precision and good accuracy. Instrumental progress in ICP-MS was achieved by the introduction of the collision cell interface in order to dissociate many disturbing argon-based molecular ions, thermalize the ions and neutralize the disturbing argon ions of plasma gas (Ar+). The application of the collision cell in ICP-QMS results in a higher ion transmission, improved sensitivity and better precision of isotope ratio measurements compared to quadrupole ICP-MS without the collision cell [e.g., for 235U/238U approximately 1 (10 microg x L(-1) uranium) 0.07% relative standard deviation (RSD) vs. 0.2% RSD in short-term measurements (n = 5)]. A significant instrumental improvement for ICP-MS is the multicollector device (MC-ICP-MS) in order to obtain a better precision of isotope ratio measurements (with a precision of up to 0.002%, RSD). CE- and HPLC-ICP-MS are used for the separation of isobaric interferences of long-lived radionuclides and stable isotopes by determination of spallation nuclide abundances in an irradiated tantalum target.

  14. The use of O, H and Sr isotopes and carbamazepine to identify the origin of water bodies supplying a shallow alluvial aquifer

    Science.gov (United States)

    Sassine, Lara; Le Gal La Salle, Corinne; Lancelot, Joël; Verdoux, Patrick

    2014-05-01

    Alluvial aquifers are of great socio-economic importance in France since they supply 82% of drinking water production, though they reveal to be very vulnerable to pesticides and emerging organic contaminants. The aim of this work is to identify the origin of water bodies which contribute to the recharge of an alluvial aquifer for a better understanding of its hydrochemistry and transfer of contaminants therein. The study is based on an isotopic and geochemical tracers approach, including major elements, trace elements (Br, Sr),and isotopes (δ18O, δ2H, 87Sr/86Sr), as well as organic molecules. Indeed, organic molecules such as pharmaceutical compounds, more precisely carbamazepine and caffeine, have shown their use as indicators of surface water in groundwater. The study area is a partially-confined shallow alluvial aquifer, the so-called Vistrenque aquifer, located at 15 km from the Mediterranean Sea, in the Quaternary alluviums deposited by an ancient arm of the Rhône River, in Southern France. This aquifer constitutes a shallow alluvial layer in a NE-SW graben structure. It is situated between a karst aquifer in lower Cretaceous limestones, on the NW border, and the Costières Plateau, on the SE border, having a similar geology as the Vistrenque. The alluvial plain is crossed by a surface water network with the Vistre as the main stream, and a canal used for irrigation essentially, the BRL canal, which is fed by the Rhône River. δ18O and δ2H allowed to differentiate the BRL canal water, depleted in heavy isotopes (δ2H = -71.5o vs V-SMOW), and the more enriched local rainwater (δ2H = -35.5o vs V-SMOW). In the Vistre surface water a binary mixing were evidenced with the BRL canal water and the rainwater, as end members. Then, in the Vistrenque groundwater both the BRL and the Vistre contributions could be identified, as they still show contrasting signature with local recharge. This allows to highlight the surface water contribution to a heavily exploited

  15. Investigating the hydrological significance of stalagmite geochemistry (Mg, Sr) using Sr isotope and particulate element records across the Late Glacial-to-Holocene transition

    Science.gov (United States)

    Belli, R.; Borsato, A.; Frisia, S.; Drysdale, R.; Maas, R.; Greig, A.

    2017-02-01

    The trace element and Sr isotope records in two coeval stalagmites characterized by different growth rates and flow regimes at Savi cave (Grotta Savi, NE Italy) reveal different sources and incorporation mechanisms for Mg and Sr. Mg is sourced primarily from dissolved cave host rock while particulate Mg derived from soil plays a subordinate role. The presence of particulate-borne Mg is inferred from the co-variation of Mg and particle-associated elements (Th, Al and Mn) which are preferentially concentrated in open columnar calcite layers. Variation in Mg concentrations corrected for particle-influenced components, the Mgc parameter, is controlled by water-rock interaction, with higher and lower Mgc during dry and wet phases, respectively. This is thought to reflect incongruent dissolution of Mg-rich phases. Correction of Sr concentrations for contributions from airborne exogenic Sr, based on 87Sr/86Sr ratios, yields the bedrock-only contribution (Src). Src variation in stalagmite calcite is influenced by speleothem growth rate and by variation of the calcite-water Sr partitioning in wet and dry phases, and only to a minor extent by incongruent dissolution of Mg-rich phases. Concentration profiles for Mgc and Srcg (corrected for growth rate effects) show inverse correlations and are inferred to show hydrological significance which is captured in a hydrological index, HI. We suggest HI provides robust information on water-rock interaction related to hydrological changes and can be utilized in both wet and semi-arid environments, provided the corrections for soil Mg and exogenic Sr can be applied with confidence. Application of the HI index allows correction of Grotta Savi oxygen isotope data, to yield a δ18Oc time series that shows when changes in moisture sources and atmospheric reorganization, or changes in moisture amount, were significant. This is especially evident during the Younger Dryas (YD). The Savi record supports the concept of a two-phase YD, marked by

  16. Tracking seasonal subglacial drainage evolution of alpine glaciers using radiogenic Nd and Sr isotope systematics: Lemon Creek Glacier, Alaska

    Science.gov (United States)

    Clinger, A. E.; Aciego, S.; Stevenson, E. I.; Arendt, C. A.

    2014-12-01

    The transport pathways of water beneath a glacier are subject to change as melt seasons progress due to variability in the balance between basal water pressure and water flux. Subglacial hydrology has been well studied, but the understanding of spatial distribution is less well constrained. Whereas radiogenic isotopic tracers have been traditionally used as proxies to track spatial variability and weathering rates in fluvial and riverine systems, these techniques have yet to be applied extensively to the subglacial environment and may help resolve ambiguity in subglacial hydrology. Research has shown the 143Nd/144Nd values can reflect variation in source provenance processes due to variations in the age of the continental crust. Correlating the 143Nd/144Nd with other radiogenic isotope systematics such as strontium (87Sr/86Sr) provides important constraints on the role of congruent and incongruent weathering processes. Our study presents the application of Nd and Sr systematics using isotopic ratios to the suspended load of subglacial meltwater collected over a single melt season at Lemon Creek Glacier, USA (LCG). The time-series data show an average ɛNd ~ -6.83, indicating a young bedrock (~60 MYA). Isotopic variation helps track the seasonal expansion of the subglacial meltwater channels and subsequent return to early season conditions due to the parabolic trend towards less radiogenic Nd in June and towards more radiogenic Nd beginning in mid-August. However, the high variability in July and early August may reflect a mixture of source as the channels diverge and derive sediment from differently aged lithologies. We find a poor correlation between 143Nd/144Nd and 87Sr/86Sr (R2= 0.38) along with a slight trend towards more radiogenic 87Sr/86Sr values with time ((R2= 0.49). This may indicate that, even as the residence time decreases over the melt season, the LCG subglacial system is relatively stable and that the bedrock is congruently weathered. Our study

  17. Rb-Sr and Nd-Sr isotope geochemistry and petrogenesis of the Misho Mountains mafic dikes (NW Iran

    Directory of Open Access Journals (Sweden)

    Maryam Ahankoub

    2017-02-01

    Full Text Available Introduction There are some theories about the Paleotethys event during the Paleozoic that have been proposed by geologists (Metcalfe, 2006. Some scientist offered some pieces of evidence about the northern margin of Gondwana (Zhu et al., 2010. The Paleotethys Ocean and Hercynian orogenic report first in Iran, have been Offered from the Morrow and Misho Mountain (Eftekharnejad, 1981. Misho Mountains is located between the north and south Misho faults and cause the formation of a positive flower structure (Moayyed and Hossainzade, 2011. There is theory about Misho southern fault as the best candidate of the Paleotethys suture zone (Moayyed and Hossainzade, 2011. Geochemistry and Sr –Nd isotopic data of the A2 granitic and Synite rocks of the East Misho, indicate that the magmatism post collision has occurred in the active continental margin by extensional zones of the following the closure of the Paleotethys (Ahankoub, 2012. Granite and syenite rocks have been cut by mafic dikes. Mafic dikes are often formed in extensional tectonic settings related to mantle plume or continental break –up (Zhu et al., 2009. In this paper, we use the geochemistry and Nd-Sr isotope data to determined petrogenesis, tectono-magmatic setting and age of Misho mafic dikes. Materials and methods After petrography study of 30 thin sections of mafic dike rocks, 8 samples were selected for whole-rock chemical analyses using ICP-MS and ICP-AES instruments by ACME Company in Vancouver, Canada. We prepared 6 sample For Sm-Nd and Rb-Sr analysis. Sr and Nd isotope ratios were measured with a thermal ionization mass spectrometer, VG Sector 54–30 at the Nagoya University. The isotope abundances of Rb, Sr, Nd, and Sm were measured by the ID method with a Finnigan MAT Thermoquad THQ thermal ionization quadrupole mass spectrometer at the Nagoya University. NBS987 and JNdi-1 were measured as natural Sr and Nd isotope ratio standards (Tanaka et al., 2000. Averages and 2σ errors

  18. Sr and Pb isotopic composition of five USGS glasses (BHVO-2G, BIR-1G, BCR-2G, TB-1G, NKT-1G)

    NARCIS (Netherlands)

    Elburg, M.A.; Vroon, P.Z.; van der Wagt, R.A.C.A.; Tchalikian, A.

    2005-01-01

    Sr isotopic compositions and Rb/Sr ratios of three USGS glasses (BHVO-2G, BIR-1G, BCR-2G) are identical to those of the original USGS reference materials. NKT-1G and TB-1G give values of 0.70351 and 0.70558, respectively. Pb isotopic ratios were measured by the standard-sample bracketing technique

  19. Use of Sr and Pb isotopes in gneissic-migmatic rocks in Itacambira-Barrocao, MG, Brazil

    International Nuclear Information System (INIS)

    Siga Junior, O.; Cordani, U.G.; Basei, M.A.S.; Kawashita, K.

    1987-01-01

    This work tries to show the potential of the Rb-Sr, Pb-Pb and K-Ar methods applied to basic geological mapping. The different interpretative values of these methodologies contribute to the understanding of the tectonic processes developed in the southeastern border of the Sao Francisco Craton. The Rb-Sr and Pb-Pb isotopic data for the gneissic-migmatitic unit of this sector indicates their generation during the Archean (-2.7 Ga) and Early Proterozoic (-2.1 Ga.). The high (Sr 87 /Sr 86 ) and μ 1 values also suggest an origin through reworking of older crustal rocks. The K-Ar data (and one fission track age) allow the thermal history of this domain to be delineated and suggest a vertical tectonic in the Late Brazilian Cycle, putting side by side blocks formed in different depths. (M.V.M.)

  20. Pb and Sr isotopic systematics of some basalts and sulfides from the East Pacific Rise at 21/sup 0/N (project RITA)

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, P. (Centre National de la Recherche Scientifique, 35 - Rennes (France). Centre Armoricain d' Etude Structurale des Socles); Clauer, N. (Centre National de la Recherche Scientifique, 67 - Strasbourg (France). Centre de Sedimentologie et Geochimie de la Surface)

    1981-10-01

    Tholeiitic basalts and sulfide deposits from the 'Cyana' and 'Alvin' diving programs (RITA project) on the East Pacific Rise were analyzed for Pb and Sr isotopes. The basalt data plot within the field defined previously by other East Pacific Rise basalts (/sup 206/Pb//sup 204/Pb: 18.35-18.58; /sup 207/Pb//sup 204/Pb: 15.48-15.53; /sup 208/Pb//sup 204/Pb: 37.8-38.1; /sup 87/Sr//sup 86/Sr: 0.7022-0.7025). Pb, U and Sr contents (approx. equal to 0.5, approx. equal to 0.05 and approx. equal to 110 ppm, respectively) and ..mu.. values (approx. equal to 6) are typical of MORB, whereas Th/U ratios (approx. equal to 3.5) are significantly higher. The Pb isotopic ratios of the sulfide samples are very homogeneous (/sup 206/Pb//sup 204/Pb approx. equal to 18.47, /sup 207/Pb//sup 204/Pb approx. equal to 15.49, /sup 208/Pb//sup 204/Pb approx. equal to 37.90), and plot in the middle of the basalt field. This indicates that the sulfide Pb was derived from the basaltic crust without any significant contribution from either seawater or hemipelagic sediments, and the solutions from which the sulfiedes were deposited had uniform Pb isotopic composition. The Pb contents of three sulfide samples is relatively high (170-1310 ppm). The Sr contents of five sulfide samples are widely scattered from 12 to 210 ppm, with /sup 87/Sr//sup 86/Sr ratios intermediate between basaltic and seawater values (0.70554 +- 0.00005 to 0.70795 +- 0.00011). Leaching experiments show that both basalt-derived Sr and seawater Sr were present in the solutions which deposited the sulfides. In some cases, Sr was also adsorbed from seawater onto the sulfides following their deposition. Basalt-derived Sr and seawater Sr are also present in associated non-sulfide phases.

  1. The suitability of annual tree growth rings as environmental archives: Evidence from Sr, Nd, Pb and Ca isotopes in spruce growth rings from the Strengbach watershed

    Science.gov (United States)

    Stille, Peter; Schmitt, Anne-Désirée; Labolle, François; Pierret, Marie-Claire; Gangloff, Sophie; Cobert, Florian; Lucot, Eric; Guéguen, Florence; Brioschi, Laure; Steinmann, Marc; Chabaux, François

    2012-05-01

    The combination of the Sr, Nd and Pb isotope systems, recognized as tracers of sources, with the Ca isotope system, known to reveal biology-related fractionations, allowed us to test the reliability of spruce (Picea abies) growth rings as environmental archives through time (from 1916 to 1983) in a forest ecosystem affected by acid atmospheric deposition. Sr and Pb isotopes have already been applied in former tree-ring studies, whereas the suitability of Nd and Ca isotope systems is checked in the present article. Our Sr and Nd isotope data indicate an evolution in the cation origin with a geogenic origin for the oldest rings and an atmospheric origin for the youngest rings. Ca isotopes show, for their part, an isotopic homogeneity which could be linked to the very low weathering flux of Ca. Since this flux is weak the spruces' root systems have pumped the Ca mainly from the organic matter-rich top-soil over the past century. In contrast, the annual growth rings studied are not reliable and suitable archives of past Pb pollution.

  2. Archean evolution of Enderby Land (Antarctica) and isotope-geochronological evidences for its ancient history

    International Nuclear Information System (INIS)

    Krylov, D.P.; Belyatskij, B.V.

    1987-01-01

    Revew of published isotope-geochronological data on Ender by Land (Antarctica), which is the region of highly metamorphic formations predominant development which includes ancient rock relicts, is presented. Three tectonic-thermal events present the Archeau evolution in the region. Correlation of isotope-geochronological (U-Pb, Rb-Sr, Sm-Nd) data with micro textural processing allows to estimate tectonic-thermal events age: 3000-3100 about 2900 and about 2500 million years. Metamorphism of 3000-3100 million years age has essentially modified all the isotope systems, while model calculations for evolution of U-Pb, Rb-Sr, Sm-Nd systems have shown that rocks primary formation accurred 3500-3900 million years ago

  3. Determination of 90Sr and Pu isotopes in contaminated groundwater samples by inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Zoriy, Miroslav V.; Ostapczuk, Peter; Halicz, Ludwik; Hille, Ralf; Becker, J. Sabine

    2005-04-01

    A sensitive analytical method for determining the artificial radionuclides 90Sr, 239Pu and 240Pu at the ultratrace level in groundwater samples from the Semipalatinsk Test Site area in Kazakhstan by double-focusing sector field inductively coupled plasma mass spectrometry (ICP-SFMS) was developed. In order to avoid possible isobaric interferences at m/z 90 for 90Sr determination (e.g. 90Zr+, 40Ar50Cr+, 36Ar54Fe+, 58Ni16O2+, 180Hf2+, etc.), the measurements were performed at medium mass resolution under cold plasma conditions. Pu was separated from uranium by means of extraction chromatography using Eichrom TEVA resin with a recovery of 83%. The limits of detection for 90Sr, 239Pu and 240Pu in water samples were determined as 11, 0.12 and 0.1 fg ml-1, respectively. Concentrations of 90Sr and 239Pu in contaminated groundwater samples ranged from 18 to 32 and from 28 to 856 fg ml-1, respectively. The 240Pu/239Pu isotopic ratio in groundwater samples was measured as 0.17. This isotope ratio indicates that the most probable source of contamination of the investigated groundwater samples was the nuclear weapons tests at the Semipalatinsk Test Site conducted by the USSR in the 1960s.

  4. Integrated elemental and Sr-Nd-Pb-Hf isotopic studies of Mesozoic mafic dykes from the eastern North China Craton: implications for the dramatic transformation of lithospheric mantle

    Science.gov (United States)

    Liu, Shen; Feng, Caixia; Santosh, M.; Feng, Guangying; Coulson, Ian M.; Xu, Mengjing; Guo, Zhuang; Guo, Xiaolei; Peng, Hao; Feng, Qiang

    2018-02-01

    Evolution of the lithospheric mantle beneath the North China Craton (NCC) from its Precambrian cratonic architecture until Paleozoic, and the transformation to an oceanic realm during Mesozoic, with implications on the destruction of cratonic root have attracted global attention. Here we present geochemical and isotopic data on a suite of newly identified Mesozoic mafic dyke swarms from the Longwangmiao, Weijiazhuang, Mengjiazhuang, Jiayou, Huangmi, and Xiahonghe areas (Qianhuai Block) along the eastern NCC with an attempt to gain further insights on the lithospheric evolution of the region. The Longwangmiao dykes are alkaline with LILE (Ba and K)- and LREE-enrichment ((La/Yb) N > 4.3) and EM1-like Sr-Nd-Pb-Hf isotopic signature ((87Sr/86Sr) i > 0.706; ε Nd (t) 16.6, (207Pb/204Pb) i > 15.4, (208Pb/204Pb) i > 36.8, ε Hf (t) 3.7), and display similar EM1-like isotopic features ((87Sr/86Sr) i > 0.706; ε Nd (t) 16.7, (207Pb/204Pb) i > 15.4, (208Pb/204Pb) i > 36.9, ε Hf (t) 2.4) and EM1-like isotopic features((87Sr/86Sr) i > 0.706; ε Nd (t) 16.7, (207Pb/204Pb) i > 15.4, (208Pb/204Pb) i > 36.9, ε Hf (t) 3.7) and EM1-like Sr-Nd-Pb-Hf isotopic features ((87Sr/86Sr) i > 0.706; ε Nd(t) 16.7, (207Pb/204Pb) i > 15.4, (208Pb/204Pb) i > 36.9, ε Hf (t) 9.3) and EM1-like isotopic composition ((87Sr/86Sr) i > 0.705; ε Nd (t) 16.9, (207Pb/204Pb) i > 15.5, (208Pb/204Pb) i > 36.9, ε Hf (t) 0.705; ε Nd (t) 16.9, (207Pb/204Pb) i > 15.5, (208Pb/204Pb) i > 36.9, ε Hf (t) < -8.6). Our data from the various mafic dyke suites suggest that the magmas were derived from EM1-like lithospheric mantle, corresponding to lithospheric mantle modified by the previously foundered lower crust beneath the eastern NCC. Our results suggest contrasting lithospheric evolution from Triassic (212 Ma) to Cretaceous (123 Ma) beneath the NCC. These mafic dykes mark an important phase of lithospheric thinning in the eastern North China Craton.

  5. Experimental study of the Mg and Sr isotopic evolution of seawater interacting with basalt between 150 and 300 ° C.

    Science.gov (United States)

    Voigt, Martin; Pearce, Christopher R.; Oelkers, Eric H.

    2016-04-01

    The chemical exchange of material between seawater and the oceanic crust plays a major role in marine geochemical cycles [1]. Isotopic signatures provide an important means of tracing elemental transfer in hydrothermal environments, yet only a limited amount of experimental data on the extent of isotopic fractionation under these conditions is currently available. This study consequently investigated the extent of δ26/24Mg and 87Sr/86Sr isotopic variation during a seawater-basalt interaction experiments at 150, 250 and 290 ° C. A suite of closed system experiments were run for several months at each temperature under saturated water pressure, using either crystalline or glassy basalt as the starting material and a water/rock ratio of 10 or 25. Our results demonstrate that the dissolution of basaltic material in hydrothermal environments occurs at the same time as the precipitation of alteration minerals (mainly smectite and anhydrite), which is consistent with results from similar studies in the past (e.g. [2]). As expected, the rate of reaction using crystalline basalt was slower than with basaltic glass, and both sample types reacted faster at higher temperatures. The 87Sr/86Sr composition of the experimental fluids decreased from the initial seawater value (0.70916) towards the lower basaltic signature during the experiments (0.70317), demonstrating the progressive release of Sr during basalt dissolution. Magnesium was steadily removed from the fluid via the precipitation of clay minerals, with the residual fluids having progressively lighter δ26/24Mg compositions. The mean Mg isotope fractionation factor (αsolid-solution) observed at 250 oC was 1.0005±0.0002, supporting low-temperature evidence that clay minerals preferentially incorporate isotopically heavy magnesium [3]. These experiments provide quantitative information on the extent of Mg isotopic fractionation between fluids and secondary silicate minerals in hydrothermal systems, and demonstrate the

  6. Sr and Ar isotope studies of detrital smectites from the Atlantic Ocean (D.S.D.P., Legs 43, 48 and 50)

    International Nuclear Information System (INIS)

    Clauer, N.; Lucas, J.

    1984-01-01

    Mineralogical, morphological and isotopic (Rb-Sr and K-Ar) determinations were made on some detrital smectites of Palaeocene and Cenomanian ages from D.S.D.P. drillings in the Atlantic Ocean. These minerals are not inert in their depositional environment; authigenic laths grow on detrital sheets with sharp borders. This authigenesis could occur slightly after deposition in a closed system, for some of these smectites. It has been tentatively quantified by the Rb-Sr and K-Ar isotopic methods, which seem also well suited to evaluate the chemical extent of this authigenesis. At least, no preferential loss of 40 Ar vs. 87 Sr could be detected in the minerals, even in those which are smaller than 0.2 μm. (Auth.)

  7. Research on evolutionary laws of Sr, Nd, Pb isotopes of uranium metallization and volcanic rocks in south china

    International Nuclear Information System (INIS)

    Ying Junlong

    1998-01-01

    According to research on evolutionary tracer of Sr, Nd, Pb isotopes, the author proposes that isotopic evolution of Mesozoic volcanics in south China is controlled by regionally metamorphic rocks of ancient land basement, early reformed derivates and recycled continental crust. Isotopic composition of uranium metallization shows the characteristics of crust sources, and Yanshanian accretion of continental margin caused the crust movement such as magmatic activity in lower crust within continent, extension-down-faulting, etc., promoting the migration, enrichment and ore formation of uranium

  8. Nd, Sr and Pb isotopic systematics in a three-component mantle: a new perspective

    International Nuclear Information System (INIS)

    Zindler, A.; Goldstein, S.

    1982-01-01

    Average Nd, Sr and Pb isotopic compositions for oceanic basalts indicate that the present day mantle consists of three chemically independent components. The recognition of a third mantle component obviates geochemical arguments which have been used to support chemical stratification and convective decoupling within the mantle, and the transport of lead to the core throughout geological time. (author)

  9. Tracing of aerosol sources in an urban environment using chemical, Sr isotope, and mineralogical characterization.

    Science.gov (United States)

    Duarte, Regina M B O; Matos, João T V; Paula, Andreia S; Lopes, Sónia P; Ribeiro, Sara; Santos, José Francisco; Patinha, Carla; da Silva, Eduardo Ferreira; Soares, Rosário; Duarte, Armando C

    2017-04-01

    In the framework of two national research projects (ORGANOSOL and CN-linkAIR), fine particulate matter (PM 2.5 ) was sampled for 17 months at an urban location in the Western European Coast. The PM 2.5 samples were analyzed for organic carbon (OC), water-soluble organic carbon (WSOC), elemental carbon (EC), major water-soluble inorganic ions, mineralogical, and for the first time in this region, strontium isotope ( 87 Sr/ 86 Sr) composition. Organic matter dominates the identifiable urban PM 2.5 mass, followed by secondary inorganic aerosols. The acquired data resulted also in a seasonal overview of the carbonaceous and inorganic aerosol composition, with an important contribution from primary biomass burning and secondary formation processes in colder and warmer periods, respectively. The fossil-related primary EC seems to be continually present throughout the sampling period. The 87 Sr/ 86 Sr ratios were measured on both the labile and residual PM 2.5 fractions as well as on the bulk PM 2.5 samples. Regardless of the air mass origin, the residual fractions are more radiogenic (representative of a natural crustal dust source) than the labile fractions, whose 87 Sr/ 86 Sr ratios are comparable to that of seawater. The 87 Sr/ 86 Sr ratios and the mineralogical composition data further suggest that sea salt and mineral dust are important primary natural sources of fine aerosols throughout the sampling period.

  10. Experiences with the determination of Sr-89 and Sr-90 using fast methods; Erfahrungen bei der Bestimmung von {sup 89}Sr und {sup 90}Sr mittels Schnellmethoden

    Energy Technology Data Exchange (ETDEWEB)

    Kowalik, C.; Fueger, J. [Thueringer Landesanstalt fuer Umwelt und Geologie, Jena (Germany). Landesmessstelle fuer Umweltradioaktivaet

    2014-01-20

    Quick methods of the measurement of {sup 89}Sr and {sup 90}Sr have a great importance in the supervision of the environmental radioactivity. It is necessary to receive in short time dependable analytical data to be able to carry out suitable assessments or to give recommendations. The aim of the investigations was to be guaranteed the demands for these methods (test preparation, measurement and evaluation). The use of the solid phase extraction by means of commercial Sr Resin trademark columns (4.4' (5')-Di-tert-butylcyclohexanol-18-kronen-6-aether) (Triskem) to the radiochemical separation of the Sr isotopes was suitable. The measurements occurred to the FHT 770 T12 - Multi Low Level Alpha/Beta Sample Counter (Thermo Scientific). The results contain the summary activities of all available Sr isotopes, as for example {sup 89}Sr and {sup 90}Sr. The calculations of the single activities occur about the mathematical algorithm of the linear development on the basis of the works of G. Kanisch. The first results show, this method is suitable for the analysis of {sup 89}Sr and {sup 90}Sr and is used therefore in future in Thuringia.

  11. Effects of interaction between ultramafic tectonite and mafic magma on Nd-Pb-Sr isotopic systems in the Neoproterozoic Chaya Massif, Baikal-Muya ophiolite belt

    Science.gov (United States)

    Amelin, Yuri V.; Ritsk, Eugeni Yu.; Neymark, Leonid A.

    1997-04-01

    Sm-Nd, Rb-Sr and U-Pb isotopic systems have been studied in minerals and whole rocks of harzburgites and mafic cumulates from the Chaya Massif, Baikal-Muya ophiolite belt, eastern Siberia, in order to determine the relationship between mantle ultramafic and crustal mafic sections. Geological relations in the Chaya Massif indicate that the mafic magmas were emplaced into, and interacted with older solid peridotite. Hand picked, acid-leached, primary rock-forming and accessory minerals (olivine, orthopyroxene, clinopyroxene and plagioclase) from the two harzburgite samples show coherent behavior and yield 147Sm/ 144Nd- 143Nd/ 144Nd and 238U/ 204Pb- 206Pb/ 204Pb mineral isochrons, corresponding to ages of 640 ± 58 Ma (95% confidence level) and 620 ± 71 Ma, respectively. These values are indistinguishable from the crystallization age of the Chaya mafic units of 627 ± 25 Ma (a weighted average of internal isochron Sm-Nd ages of four mafic cumulates). The Rb-Sr and Sm-Nd isotopic systems in the harzburgite whole-rock samples were disturbed by hydrothermal alteration. These alteration-related isotopic shifts mimic the trend of variations in primary isotopic compositions in the mafic sequence, thus emphasizing that isotopic data for ultramafic rocks should be interpreted with great caution. On the basis of initial Sr and Nd values, ultramafic and mafic rocks of the Chaya Massif can be divided into two groups: (1) harzburgites and the lower mafic unit gabbronorites withɛ Nd = +6.6 to +7.1 andɛ Sr = -11 to -16; and (2) websterite of the lower unit and gabbronorites of the upper mafic unit:ɛ Nd = +4.6 to +6.1 andɛ Sr = -8 to -9. Initial Pb isotopic ratios are identical in all rocks studied, with mean values of 206Pb/ 204Pb= 16.994 ± 0.023 and 207Pb/ 204Pb= 15.363 ± 0.015. The similarity of ages and initial isotopic ratios within the first group indicates that the isotopic systems in the pre-existing depleted peridotite were reset by extensive interaction with

  12. Rb-Sr Isotopic Systematics of Alkali-Rich Fragments in the Yamato-74442 LL-Chondritic Breccia

    Science.gov (United States)

    Yokoyama, T.; Misawa, K.; Okano, O.; Shih, C.-Y.; Nyquist, L. E.; Simo, J. I.; Tappa, M. J.; Yoneda, S.

    2012-01-01

    Alkali-rich igneous fragments were identified in the brecciated LL-chondrites, Kr henberg (LL5)], Bhola (LL3-6) and Yamato (Y)-74442 (LL4), and show characteristic fractionation patterns of alkaline elements. The K-Rb-Cs-rich fragments in Kr henberg, Bhola, and Y-74442 are very similar in mineralogy and petrography (olivine + pyroxene + glass), suggesting that they could have come from related precursor materials. We have undertaken Rb-Sr isotopic studies on alkali-rich fragments in Y-74442 to precisely determine their crystallization ages and the isotopic signatures of their precursor material(s).

  13. Use of the {sup 87}Sr/{sup 86}Sr isotopic ratio as an environmental tracer: an example of the application to the Fossil Forest of the Dunarobba (FFD) sedimentary system near Aviglano Umbro (Terni-Central Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Barbieri, M

    2002-12-01

    A recent discovery of Pliocene tree trunks (Taxodium, Glyptostrobus or Sequoia) perfectly preserved in the fluvial lacustrine sediments deposited in the old Tiberin Lake (near the town of Dunarobba, Central Italy) has led to the study of the conditions responsible for the trunks preservation. The present work has applied Sr isotope techniques to examine and confirm fluid migration in the different sediment types which cross the entire fluvial-lacustrine sequence. Based on the {sup 87}Sr/{sup 86}Sr ratios measured in carbonate and in silicate fractions of samples collected from a bore hole (from 0 to 120 m) it is concluded that each sedimentary level has limited communication between zones and is characterised by different isotope values. This suggests that the intrinsic properties of these clays make them a good material for isolating waste, both for direct use and for a better buffer in other formations, possibly less secure, such as salt or granite. The results obtained in the present work have demonstrated some of the potential uses of the {sup 87}Sr/{sup 86}Sr isotopic ratio as an environmental tracer for confirming results from some of the geotechnical (such as permeability) and geochemical parameters of these host sediments.

  14. Geochronological synthesis of Bahia state and the crustal evolution, based in evolution diagram of Sr and initial rate of Sr87/Sr86

    International Nuclear Information System (INIS)

    Sato, K.

    1986-01-01

    The crustal evolution of the ancient terrains of the State of Bahia, Brazil, is attempted with the aid of Sr isotopic results as natural tracers. Some Nd and Pb isotopic data are also available, and support the main conclusions based on Sr evolution diagrams. The analysis of the Sr evolution diagrams shows that the Archean Terrains are mainly formed by accretion from mantle-derived material, but crustal reworking is indicated by the high initial 87 Sr/ 86 Sr value of the Jequie Complex. The Transamazonian mobile belt include both types of materials, but the 87 Sr/ 86 Sr value, generally lower than those of the Jequie Complex, markes improbable a direct derivation. During Middle and Late Proterozoic, the continental crust was already well consolidated, and reworking of crustal material predominated within the Espinhaco and Brasiliano folded systems [pt

  15. A geochemical and Pb, Sr isotopic study of the evolution of granite-gneisses from the Bastar craton, Central India

    International Nuclear Information System (INIS)

    Sarkar, G.; Paul, D.K.; Misra, V.P.; de Laeter, J.R.; Mc Naughton, N.J.

    1990-01-01

    Preliminary Pb-Pb and Rb-Sr geochronology of granitic and gneissic rocks from the Sukma area of the Bastar craton, Central India, provides important constraints on crustal evolution. Much of the craton is made up of felsic orthogneisses and younger granitic intrusives, compositionally ranging from tonalite to granite. Pb-Pb isotopic data suggest the presence of ca. 3.0 Ga old gneisses. Younger granitic intrusives have been dated at ca. 2.6 Ga which represents a widespread resetting and/or emplacement event. Comparison of the Pb-Pb and Rb-Sr whole rock ages suggests that the latter were more perturbed after the gneiss-forming or emplacement events. All rock suites show significant geological scatter of isotopic data probably because of sampling on a regional scale, and reflect multi-stage isotopic evolution in a complex terrain. The present isotopic data indicate the presence of Archaean rock in the Bastar craton and suggest temporal similarity with the oldest crustal rocks in the Singhbhum and Dharwar cratons. (author). 18 refs., 4 tabs., 8 figs

  16. In situ Sr/Sr investigation of igneous apatites and carbonates using laser-ablation MC-ICP-MS

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Simonetti, A.; Stevenson, R.K.

    2003-01-01

    In situ Sr isotopic compositions of coexisting apatite and carbonate for carbonatites from the Sarfartoq alkaline complex, Greenland, have been determined by laser-ablation multicollector inductively coupled plasma mass spectrometry. This study is the first to examine the extent of Sr isotopic ho...

  17. Development of 87Sr/86Sr maps as targeted strategy to support wine quality.

    Science.gov (United States)

    Durante, Caterina; Bertacchini, Lucia; Cocchi, Marina; Manzini, Daniela; Marchetti, Andrea; Rossi, Maria Cecilia; Sighinolfi, Simona; Tassi, Lorenzo

    2018-07-30

    This study summarizes the results obtained from a systematic and long-term project aimed at the development of tools to assess the provenance of food in the oenological sector. In particular, 87 Sr/ 86 Sr isotope ratios were measured on statistically representative set of soils, vine branches and wines sampled in the production district of Modena, worldwide known for the Lambrusco wines production. The obtained data were used to build strontium isotopic maps able to objectively support the Lambrusco PDO wines origin as well as other products of the Modena district. Finally, a strong relationship was found between the 87 Sr/ 86 Sr isotope ratios of soils and vine branches on a large scale, highlighting and confirming once more the idea that plants can also represent an optimal sampling device to support geographical traceability. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Radiogenic isotope geochemistry of sedimentary and aquatic systems

    International Nuclear Information System (INIS)

    Stille, P.; Shields, G.

    1997-01-01

    The following topics are discussed: Basic principles of isotopic geochemistry; weathering; isotopic geochemistry of river water; isotopic geochemistry in the environment; isotopic composition of seawater past and present (Sr, Nd, Pb, Os, Ce); isotope geochemistry of detrital and authigenic clay minerals in marine sediemnts (Rb-Sr, K-Ar, O); the Sm-N isotope system in detrital and authigenic argillaceous sediments. (SR), provided they are of exceptional interest and focused on a single topic. (orig./SR)

  19. Radiogenic isotope geochemistry of sedimentary and aquatic systems

    Energy Technology Data Exchange (ETDEWEB)

    Stille, P.; Shields, G. [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France). Centre de Sedimentologie et Geochimie de la Surface

    1997-12-31

    The following topics are discussed: Basic principles of isotopic geochemistry; weathering; isotopic geochemistry of river water; isotopic geochemistry in the environment; isotopic composition of seawater past and present (Sr, Nd, Pb, Os, Ce); isotope geochemistry of detrital and authigenic clay minerals in marine sediemnts (Rb-Sr, K-Ar, O); the Sm-N isotope system in detrital and authigenic argillaceous sediments. (SR), provided they are of exceptional interest and focused on a single topic. (orig./SR)

  20. NGRI LAM-MC-ICPMS National Facility: reproducibility of Sr, Nd and Hf isotopic measurements

    International Nuclear Information System (INIS)

    Bhaskar Rao, Y.J.; Vijaya Gopal, B.; Babu, E.V.S.S.K.; Sukumaran, N.P.; Sreenivas, B.; Vijaya Kumar, T.; Krishna, K.V.S.S.; Tomson, J.K.

    2009-01-01

    A laboratory facility was established at the NGRI, primarily to support research in Isotope Geochemistry and Geochronology. Central to this facility are a Multiple Collector-Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS: Nu Plasma HR, Nu Instruments, UK) and a 213 nm Nd-YAG UV Laser Ablation Microprobe (LAM: UP-213, New Wave Research, USA) and a clean chemistry laboratory for dissolution and chromatographic extraction of a range of elements. This article presents a summary of the accuracy and precision of MC-ICPMS Sr, Nd and Hf isotopic measurements (solution mode) on Standard Reference Materials: SRM-987, JNd i and JMC-475 respectively, measured between October 2007 and August 2009

  1. Nd and Sr isotopes: implications of provenance and geological mapping

    International Nuclear Information System (INIS)

    Albuquerque, Marcio Fernando dos Santos; Horbe, Adriana Maria Coimbra; Dantas, Elton Luiz

    2015-01-01

    XRD, Nd and Sr isotopes, major, minor and traces elements quantification were applied to rocks, lateritic crusts and soils from Sumauma Supergroup and Alto Tapajos Group, in order to indicate provenance of the rocks and using lateritic products as geologic mapping tool. For the rocks, the results showed sources related to provinces Tapajos Parima, Rondonia Juruena, Sunsas, Carajas and Amazonia Central. However, the incision of Cachimbo graben allowed which the Sumauma Supergroup erosion also were source for the Alto Tapajos Group, allied to contribution of volcanics from Colider Group. Lateritic crusts and soils are correlates to bedrocks, allowing the use as geologic mapping tool. (author)

  2. Petrogenesis and origin of the Upper Jurassic-Lower Cretaceous magmatism in Central High Atlas (Morocco): Major, trace element and isotopic (Sr-Nd) constraints

    Science.gov (United States)

    Essaifi, Abderrahim; Zayane, Rachid

    2018-01-01

    During an uplift phase, which lasted ca. 40 Ma, from the Late Jurassic (165 Ma) to the Early Cretaceous (125 Ma), transitional to moderately alkaline magmatic series were emplaced in the Central High Atlas. The corresponding magmatic products include basaltic lava flows erupted within wide synclines and intrusive complexes composed of layered mafic intrusions and monzonitic to syenitic dykes emplaced along narrow anticlinal ridges. The igneous rock sequence within the intrusive complexes is composed of troctolites, olivine-gabbros, oxide-gabbros, monzonites and syenites. The chemical compositions of the various intrusive rocks can be accounted for by crystal accumulation, fractional crystallization and post-magmatic remobilization. The evolution from the troctolites to the syenites was mainly controlled by a fractional crystallization process marked by early fractionation of olivine, plagioclase and clinopyroxene, followed by separation of biotite, amphibole, apatite, and Ti-magnetite. Hydrothermal activity associated with emplacement of the intrusions within the Jurassic limestones modified the elemental and the Sr isotopic composition of the hydrothermally altered rocks In particular the monzonitic to syenitic dykes underwent an alkali metasomatism marked by depletion in K and Rb and enrichment in Na and Sr. As a result, their Sr isotopic composition was shifted towards higher initial Sr isotopic ratios (0.7067-0.7075) with respect to the associated gabbros (0.7036-0.7046). On the contrary, the Nd isotopic compositions were preserved from isotope exchange with the limestones and vary in a similar range to those of the gabbros (+1.6 < εNdi < +4.1). The isotopic and the trace element ratios of the uncontaminated samples were used to constrain the source characteristics of this magmatism. The Sr-Nd isotopic data and the incompatible element ratios (e.g. La/Nb, Zr/Nb, Th/U, Ce/Pb) are consistent with generation from an enriched upper mantle similar to an ocean

  3. Sr isotope geochemistry of voluminous acidic pyroclastics erupted at 1-3 Ma in Northeast Japan

    International Nuclear Information System (INIS)

    Shirahase, Teruo; Tamanyu, Shiro; Togashi, Shigeko

    1989-01-01

    Sr isotope ratios are analyzed for voluminous acidic pyroclastics erupted at 1 - 3 Ma in five areas on the volcanic front of Northeast Japan. The initial values of 87 Sr/ 86 Sr ratios range from 0.7040 to 0.7055. There is no significant difference in ratios between 1 - 3 Ma acidic pyroclastics and 0 - 1 Ma andesitic volcanics in each area in spite of differences in age and in mean SiO 2 content. On the other hand, the ratios in both of 1 - 3 Ma and 0 - 1 Ma volcanics vary along arc in the same manner. The changes of Sr and Rb contents in each area are consistent with systematic changes by fractional crystallization. The low 87 Sr/ 86 Sr ratios and chemistry suggest that 1 - 3 Ma acidic pyroclastics of Northeast Japan formed by a high degree of fractional crystallization from basic magma which is common in genesis with young andesitic volcanism. The mechanisms of the formation of the basic magma and the character of mantle source in each area have not changed for the past 3 Ma. Degrees of fractional crystallization changed with changes of the tectonic condition of shallow magma chamber from a weak horizontal compression stress field to a strong one. (author)

  4. Fractionation of cesium isotopes and 90Sr in snowmelt run-off and lake waters from a contaminated Norwegian mountain catchment

    International Nuclear Information System (INIS)

    Salbu, B.; Bjoernstad, H.E.; Brittain, J.E.

    1992-01-01

    Cesium isotopes and 90 Sr have been determined in the inflow and outflow rivers of a Norwegian subalpine lake. The lake is situated in an area contaminated by Chernobyl fallout. Sampling was carried out during the spring peak discharge period associated with snowmelt. Transported coarse particulate plant material was collected by traps. Particles and colloids were removed from water samples by hollow fibre ultrafiltration. The results illustrate that run-off during the spring snowmelt is an important pathway for these radionuclides. The cesium isotopes are predominantly transported as colloids, while 90 Sr is present in the form of low molecular weight mobile species. Based on lake budget calculations, more than 50% of the cesium input is retained in the lake, while more than 90% of the 90 Sr is transported through the lake and into lower parts of the drainage system. (author) 16 refs.; 6 figs.; 3 tabs

  5. Is the Modern Marine 87Sr/86Sr Cycle Balanced?

    Science.gov (United States)

    Peucker-Ehrenbrink, B.

    2017-12-01

    The marine 87Sr/86Sr record is one of the best-reconstructed isotope records with thousands of high quality measurements spanning the past 800 million years. It records a global signal of tectonic, biotic and climatic processes on Earth. Yet despite decades of research we still do not know whether the current marine Sr budget is in steady state. Studies of the marine 88Sr/86Sr record indicate that sources and sinks do not balance. The magnitude and isotope composition of the terrestrial inputs are being debated, and the magnitude and temporal variability of unradiogenic contributions are not well constrained. Here I provide a revised assessment of all continental sources of Sr to the ocean, including river runoff, submarine groundwater discharge (Beck et al., 2013), dissolution of riverine suspended matter in seawater and dissolution of volcanic ash deposited on the ocean (Jones et al., 2012). I contrast continental sources of Sr with estimates of marine sources of Sr to seawater, specifically high- and low-temperature submarine hydrothermal fluids, as well as diffusive diagenetic fluxes. Best current data imply that unradiogenic submarine hydrothermal inputs to seawater are insufficient to balance the flux of radiogenic continental Sr. The revised assessment of riverine contributions is based on Sr data for almost 230 rivers, an increasing amount of time-series data for such rivers, as well as river discharge and sediment flux data for more than 2000 rivers. Regional sampling biases have been corrected with the aid of digital bedrock maps, specifically along the western margin of North America, East Africa and the large drainage region of Arabia, India and SE Asia. Significant uncertainty in the chemical and isotopic compositions of runoff from Greenland and East Africa remains. The main uncertainty in the budget, however, is related to the possibility that modern rivers do not represent the pre-anthropogenic (natural) state of continental runoff (e.g. Ganges

  6. Insights into the diagenetic environment of fossil marine vertebrates of the Pisco Formation (late Miocene, Peru) from mineralogical and Sr-isotope data

    Science.gov (United States)

    Gioncada, A.; Petrini, R.; Bosio, G.; Gariboldi, K.; Collareta, A.; Malinverno, E.; Bonaccorsi, E.; Di Celma, C.; Pasero, M.; Urbina, M.; Bianucci, G.

    2018-01-01

    The late Miocene Pisco Formation of Peru is an outstanding example of richness and high-quality preservation of fossil marine vertebrates. In order to reconstruct the fossilization path, we present new textural, mineralogical and Sr-isotope data of diagenetic minerals formed in correspondence of fossil specimens such as marine vertebrates and mollusks. These fossil specimens were found at Cerro los Quesos, in the Ica Desert, within the diatomaceous strata of the Pisco Formation. Dolomite, gypsum, anhydrite and Mn minerals are the main phases found, while the calcium carbonate originally forming the mollusk valves is replaced by gypsum. An early formation of dolomite and of Mn minerals, triggered by the modifications of the geochemical environment due to organic matter degradation, is suggested by the textural relationships and is confirmed by the Sr isotopic ratio of dolomite, which agrees with that of seawater at the time of sedimentation. Instead, gypsum Sr isotopic ratios indicate a pre-Miocene seawater-derived brine circulating within the sedimentary sequence as a source for Sr. Oxidation of diagenetic sulfide causing a lowering of the pH of porewater is proposed as an explanation for Ca-carbonate dissolution. The diagenetic chemical environment was, nevertheless, favorable to bone preservation.

  7. Application of heavy stable isotopes in forensic isotope geochemistry: A review

    International Nuclear Information System (INIS)

    Aggarwal, Jugdeep; Habicht-Mauche, Judith; Juarez, Chelsey

    2008-01-01

    Light stable isotopes have been used for many years to characterize the source and transport of materials. More recently heavy isotope systems such as Sr, Nd and Pb have been added to this list in order to aid source identification. With the advent of multiple collector ICP-MS, the range of isotopic tools now available has increased considerably, however, until the isotope systematics of these new non-traditional isotope systems have become better understood, they will not be as useful in characterizing material source and transportation. Applications using heavy metal stable isotopes (mostly traditional heavy isotopes) have reached most avenues in science, including earth sciences, archaeology, anthropology, animal physiology, ecology and toxicology. This field will continue to grow as new applications are developed and techniques become simpler and quicker. This paper provides a review of how this field has grown and presents two new applications using Pb and Sr isotopes in glazes to determine the source of ore used in glazes, and using Sr isotopes to determine the origin of undocumented deceased Mexican border crossers

  8. Application of heavy stable isotopes in forensic isotope geochemistry: A review

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Jugdeep [W.M. Keck Isotope Laboratory, Department of Earth Sciences, University of California, Santa Cruz, CA 95064 (United States)], E-mail: jaggarwal@pmc.ucsc.edu; Habicht-Mauche, Judith; Juarez, Chelsey [Department of Anthropology, University of California, Santa Cruz, CA 95064 (United States)

    2008-09-15

    Light stable isotopes have been used for many years to characterize the source and transport of materials. More recently heavy isotope systems such as Sr, Nd and Pb have been added to this list in order to aid source identification. With the advent of multiple collector ICP-MS, the range of isotopic tools now available has increased considerably, however, until the isotope systematics of these new non-traditional isotope systems have become better understood, they will not be as useful in characterizing material source and transportation. Applications using heavy metal stable isotopes (mostly traditional heavy isotopes) have reached most avenues in science, including earth sciences, archaeology, anthropology, animal physiology, ecology and toxicology. This field will continue to grow as new applications are developed and techniques become simpler and quicker. This paper provides a review of how this field has grown and presents two new applications using Pb and Sr isotopes in glazes to determine the source of ore used in glazes, and using Sr isotopes to determine the origin of undocumented deceased Mexican border crossers.

  9. The use Pb- and Sr- isotopes for the study of Pacific Islander population

    International Nuclear Information System (INIS)

    Budd, P.; Gulson, B.L.; Montgomery, J.; Rainbird, P.; Thomas, R.G.; Young, S.

    1997-01-01

    Lead isotope measurements of dental enamel are regularly used as a means of determining information as to the source of the lead burden in modern human populations (Gulson and Wilson 1994). Lead ions have a considerable propensity to replace calcium ions in skeletal hard tissue; principally composed of hydroxy-apatite. The lead isotopic composition of teeth in adult humans has been shown to relate directly to the subject's exposure to the element at the time of eruption of their adult teeth and is unaffected by changes in the lead burden of an individual in latter life. In children, the analogous lead burden relates to the lead exposure of the mother during pregnancy and in the neo-natal period. Moreover due to its high crystallinity and density dental enamel does not undergo post-mortem recrystallization. This fact raised the exciting possibility that isotopic measurements of hard tissue could be used as a means of determining whether and individual is a migrant to a particular region. Despite a number of complications, briefly described, this paper presents the results of the ongoing study which uses measurements of Sr and Pb isotopes within dental enamel to determine the origin of Pacific Islander populations

  10. Chapter 9 The magma feeding system of Somma-Vesuvius (Italy) strato-volcano: new inferences from a review of geochemical and Sr, Nd, Pb and O isotope data

    Science.gov (United States)

    Piochi, M.; de Vivo, B.; Ayuso, R.A.

    2006-01-01

    A large database of major, trace and isotope (Sr, Nd, Pb, O) data exists for rocks produced by the volcanic activity of Somma-Vesuvius volcano. Variation diagrams strongly suggest a major role for evolutionary processes such as fractional crystallization, contamination, crystal trapping and magma maxing, occurring after magma genesis in the mantle. Most mafic magmas are enriched in LILE (Light Ion Lithophile Elements; K. Rb, Ba), REE (Ce, Sm) and Y, show small Nb-Ta negative anomalies, and have values of Nb/Zr at about 0.15. Enrichments in LILE, REE, Nb and Ta do not correlate with Sr isotope values or degree of both K enrichment and silica undersaturation. The results indicate mantle source heterogeneity produced by slab-derived components beneath the volcano. However, the Sr isotope values of Somma-Vesuvius increase from 0.7071 up to 0.7081 with transport through the uppermost 11-12 km of the crust. The Sr isotope variation suggests that the crustal component affected the magmas during ascent through the lithosphere to the surface. Our new geochemical assessment based on chemical, isotopic and fluid inclusion data points to the existence of three main levels of magma storage. Two of the levels are deep and may represent long-lived reservoirs; the uppermost crustal level probably coincides with the volcanic conduit. The deeper level of magma storage is deeper than 12 km and fed the 1944 AD eruption. The intermediate level coincides with the seismic discontinuity detected by Zollo et al. (1996) at about 8 km. This intermediate level supplies magmas with 87Sr/86Sr values between 0.7071 and 0.7074, and ??O18system. ?? 2006 Elsevier B.V. All rights reserved.

  11. Plume-related mantle source of super-large rare metal deposits from the Lovozero and Khibina massifs on the Kola Peninsula, Eastern part of Baltic Shield: Sr, Nd and Hf isotope systematics

    Science.gov (United States)

    Kogarko, L. N.; Lahaye, Y.; Brey, G. P.

    2010-03-01

    The two world’s largest complexes of highly alkaline nepheline syenites and related rare metal loparite and eudialyte deposits, the Khibina and Lovozero massifs, occur in the central part of the Kola Peninsula. We measured for the first time in situ the trace element concentrations and the Sr, Nd and Hf isotope ratios by LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometer) in loparite, eudialyte an in some other pegmatitic minerals. The results are in aggreement with the whole rock Sr and Nd isotope which suggests the formation of these superlarge rare metal deposits in a magmatic closed system. The initial Hf, Sr, Nd isotope ratios are similar to the isotopic signatures of OIB indicating depleted mantle as a source. This leads to the suggestion that the origin of these gigantic alkaline intrusions is connected to a deep seated mantle source—possibly to a lower mantle plume. The required combination of a depleted mantle and high rare metal enrichment in the source can be explained by the input of incompatible elements by metasomatising melts/fluids into the zones of alkaline magma generation shortly before the partial melting event (to avoid ingrowth of radiogenic isotopes). The minerals belovite and pyrochlore from the pegmatites are abnormally high in 87Sr /86Sr ratios. This may be explained by closed system isotope evolution as a result of a significant increase in Rb/Sr during the evolution of the peralkaline magma.

  12. Geochemistry of trace elements and Sr- Nd isotopes of foraminifera shell from the Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Trace elemental associations and Sr - Nd isotopic compositions are of important to recognition of biogenic material from mixed marine sediments. The foraminifera shell from the Okinawa Trough strongly enrichesSr, P, Mn andBa, enriches Li, U, Th, Sc, Co, Cu, Pb, Zn, Cr, Rb, Y, Sb and light rare earth elements, slightly enriches V, Ga, Zr, Nb, Cd and middle rare earth elements,is short of Mo, In, Sn, Cs, Hf, Ta, W, Ti, Bi and heavy rare earth elements. The mechanism of elemental enrichment in forminifera is the concentrations of trace elements in sea water and selective absorption of trace elements during foraminifera living, as well as the geochemical affinity between major elements and trace elements. The REE (rare earth elements) partition pattern of foraminifera shell of the Okinawa Trough shows enrichment of middle rare earth elements with slightly negative Ce anomaly,which are different from those of foraminifera of the Pacific Ocean. The Sr, Nd isotopic ratios of the Okinawa Trough foraminifera are 0.709 769 and 0.512 162, respectively, which are different not only from those of oceanic water, but also from those of river water of China's Mainland, the former is slightly higher than those of oceanic water, but much lower than those of river water; the latter is slightly lower than those of oceanic water, but higher than those of river water, demonstrating that the Okinawa Trough sea water has been influenced by river water of China's Mainland.

  13. Elemental and isotopic (C, O, Sr, Nd) compositions of Late Paleozoic carbonated eclogite and marble from the SW Tianshan UHP belt, NW China: Implications for deep carbon cycle

    Science.gov (United States)

    Zhu, Jianjiang; Zhang, Lifei; Lü, Zeng; Bader, Thomas

    2018-03-01

    Subduction zones are important for understanding of the global carbon cycle from the surface to deep part of the mantle. The processes involved the metamorphism of carbonate-bearing rocks largely control the fate of carbon and contribute to local carbon isotopic heterogeneities of the mantle. In this study, we present petrological and geochemical results for marbles and carbonated eclogites in the Southwestern Tianshan UHP belt, NW China. Marbles are interlayered with coesite-bearing pelitic schists, and have Sr-Nd isotopic values (εNd (T=320Ma) = -3.7 to -8.9, 87Sr/86Sr (i) = 0.7084-0.7089), typical of marine carbonates. The marbles have dispersed low δ18OVSMOW values (ranging from 14 to 29‰) and unaffected carbon isotope (δ13CVPDB = -0.2-3.6‰), possibly due to infiltration of external H2O-rich fluids. Recycling of these marbles into mantle may play a key role in the carbon budget and contributed to the mantle carbon isotope heterogeneity. The carbonated eclogites have high Sr isotopic compositions (87Sr/86Sr (i) = 0.7077-0.7082) and positive εNd (T = 320 Ma) values (from 7.6 to 8.2), indicative of strong seafloor alteration of their protolith. The carbonates in the carbonated eclogites are mainly dolomite (Fe# = 12-43, Fe# = Fe2+/(Fe2+ + Mg)) that were added into oceanic basalts during seafloor alteration and experienced calcite - dolomite - magnesite transformation during the subduction metamorphic process. The uniformly low δ18O values (∼11.44‰) of carbonates in the carbontaed eclogites can be explained by closed-system equilibrium between carbonate and silicate minerals. The low δ13C values (from -3.3 to -7.7‰) of the carbonated eclogites most likely reflect contribution from organic carbon. Recycling of these carbonated eclogites with C isotope similar to typical mantle reservoirs into mantle may have little effect on the mantle carbon isotope heterogeneity.

  14. Sr evolution in the Upper Permian and Lower Triassic carbonates, northeast Sichuan basin, China: Constraints from chemistry, isotope and fluid inclusions

    International Nuclear Information System (INIS)

    Li, Kaikai; Cai, Chunfang; Jiang, Lei; Cai, Liulu; Jia, Lianqi; Zhang, Bing; Xiang, Lei; Yuan, Yuyang

    2012-01-01

    Petrographic features, C, O and Sr isotopes, rare earth and trace elements were determined, and fluid inclusions were analyzed on various stages of interparticle cements and vug-fillings from the Upper Permian and Lower Triassic sour reservoirs in northeastern Sichuan basin. The aim was to assess the origin and evolution of palaeo-waters in the carbonates. The original water was contemporary seawater, from which marine cements precipitated with slightly high Sr contents (mean 1911 ppm), 87 Sr/ 86 Sr ratios from 0.7067 to 0.7082 and nonluminescent CL. The palaeo-seawater was diluted by meteoric water, as indicated by bright cathodoluminescence (CL) and Sr-depletion (0–516 ppm) in low-temperature calcite. When buried to temperatures of about 60–90 °C during Middle to Late Triassic, the palaeo-water was enriched in Sr released from the transformation of precursor aragonite and calcite to dolomite, resulting in precipitation of substantial pre-bitumen Sr-rich minerals (SrSO 4 and SrCO 3 ). For un-dolomitized limestone sections, aragonite neomorphism may have contributed Sr to the precipitation of small amounts of Sr-bearing minerals and calcite crystals with elevated homogenization temperatures (HTs, mainly from 90 to 130 °C) and wide Sr contents (from 34 to 3825 ppm), as recorded in stage III calcite. Since the Middle Jurassic, almost all of the early stage celestite and significant amounts of solid CaSO 4 have been consumed by reactions with hydrocarbons (i.e., TSR), resulting in water enriched in isotopically light CO 2 and HCO 3 - ,Sr 2+ ,Ba 2+ and Eu 2+ , as recorded in calcite with low δ 13 C values (down to −18.9‰), 87 Sr/ 86 Sr ratios from 0.7072 to 0.7076, high HTs (mainly 110–198 °C), positive Eu anomalies and high Sr and Ba contents. Subsequently, the water was uplifted and cooled down to about 115 °C, celestite and strontianite were precipitated with the occurrence of natural elemental S immiscible inclusions. TSR may have produced

  15. The 87Sr/86Sr aquatic isoscape of the Danube catchment from the source to the mouth as tool for studying fish migrations

    Science.gov (United States)

    Zitek, Andreas; Tchaikovsky, Anastassiya; Irrgeher, Johanna; Waidbacher, Herwig; Prohaska, Thomas

    2014-05-01

    Isoscapes - spatially distributed isotope patterns across landscapes - are increasingly used as important basis for ecological studies. The natural variation of the isotopic abundances in a studied area bears the potential to be used as natural tracer for studying e.g. migrations of animals or prey-predator relations. The 87Sr/86Sr ratio is one important tracer, since it is known to provide a direct relation of biological samples to geologically distinct regions, as Sr isotopes are incorporated into living tissues as a proxy for calcium and taken up from the environment without any significant fractionation. Although until now the focus has been mainly set on terrestrial systems, maps for aquatic systems are increasingly being established. Here we present the first 87Sr/86Sr aquatic isoscape of the Danube catchment, the second largest river catchment in Europe, from near its source starting at river km 2581 in Germany down to its mouth to river km 107 in Romania. The total length of the river Danube is 2780 km draining a catchment area 801 463 km2 (10 % of the European continent). The major purpose of this study was to assess the potential of the 87Sr/86Sr isotope ratio to be used as tool for studying fish migrations at different scales in the entire Danube catchment. Within the Joint Danube Research 3 (JDS 3), the biggest scientific multi-disciplinary river expedition of the World in 2013 aiming at the assessment of the ecological status and degree of human alterations along the river Danube, water samples were taken at 68 pre-defined sites along the course of the river Danube including the major tributaries as a basis to create the so called 'Isoscape of the Danube catchment'. The determination of 87Sr/86Sr isotope ratio in river water was performed by multicollector-sector field-inductively coupled plasma-mass spectrometry (MC-SF-ICP-MS). The JDS 3 data were combined with existing data from prior studies conducted within the Austrian part of the Danube catchment

  16. Sr- and Nd- isotope variations along the Pleistocene San Pedro - Linzor volcanic chain, N. Chile: Tracking the influence of the upper crustal Altiplano-Puna Magma Body

    Science.gov (United States)

    Godoy, Benigno; Wörner, Gerhard; Le Roux, Petrus; de Silva, Shanaka; Parada, Miguel Ángel; Kojima, Shoji; González-Maurel, Osvaldo; Morata, Diego; Polanco, Edmundo; Martínez, Paula

    2017-07-01

    Subduction-related magmas that erupted in the Central Andes during the past 10 Ma are strongly affected by crustal assimilation as revealed by an increase in 87Sr/86Sr isotope ratios with time that in turn are correlated with increased crustal thickening during the Andean orogeny. However, contamination is not uniform and can be strongly influenced locally by crustal composition, structure and thermal condition. This appears to be the case along the NW-SE San Pedro - Linzor volcanic chain (SPLVC) in northern Chile, which straddles the boundary of a major zone of partial melt, the Altiplano_Puna Magma Body (APMB). Herein we report 40Ar/39Ar ages, compositional and isotope data on lavas from the SPLVC that track the influence of this zone of partial melting on erupted lavas with geochronological and geochemical data. Ages reported here indicate that SPLVC has evolved in the last 2 M.y., similar to other volcanoes of the Western Cordillera (e.g. Lascar, Uturuncu, Putana). 87Sr/86Sr ratios increase systematically along the chain from a minimum value of 0.7057 in San Pedro dacites to a maximum of 0.7093-0.7095 for the Toconce and Cerro de Leon dacites in the SE. These changes are interpreted to reflect the increasing interaction of SPLVC parental magmas with partial melt within the APMB eastwards across the chain. The 87Sr/86Sr ratio and an antithetic trend in 143Nd/144Nd is therefore a proxy for the contribution of melt from the APMB beneath this volcanic chain. Similar 87Sr/86Sr increases and 143Nd/144Nd decreases are observed in other transects crossing the boundary of the APMB. Such trends can be recognized from NW to SE between Aucanquilcha, Ollagüe, and Uturuncu volcanoes, and from Lascar volcano to the N-S-trending Putana-Sairecabur-Licancabur volcanic chain to the north. We interpret these isotopic trends as reflecting different degrees of interaction of mafic parental melts with the APMB. High 87Sr/86Sr, and low 143Nd/144Nd reveal zones where the APMB is

  17. The 3550 year BP-1944 A.D.magma-plumbing system of Somma-Vesuvius: constraints on its behaviour and present state through a review of Sr-Nd isotope data

    Directory of Open Access Journals (Sweden)

    G. Mastrolorenzo

    2004-06-01

    Full Text Available Vesuvius, dominating the densely-populated Neapolitan area, is one of the most dangerous volcanoes in the World. Its destructive power derives from energetic subplinian and plinian eruptions, such as the one which occurred in 79 A.D. Generally such large-scale events follow a long period of quiescence; a behaviour interpreted as the gradual build-up of magma volumes between periods of major activity. After the 1631 subplinian eruption until the last 1944 A.D. eruption, it experienced an almost continuous and less energetic explosive/effusive activity. The erupted magmas are characterized by undersaturated potassic to ultrapotassic nature, and compositional and Sr-isotopic variability. Furthermore geobarometric studies indicate two different crystallization depths located at 4 and >11 km, respectively. According to most of the recent literature, the eruptions were triggered by the injection in a shallower magma chamber, of isotopically distinct magma batches derived from heterogeneous mantle source(s and/or contamination processes occurred within the deep reservoir. In our review of petrochemical data, we consider the period between the 3550 years BP plinian eruption and the 472 A.D. sub-plinian eruption, which includes 79 A.D. event, and the most recent period of activity which started in 1631 A.D. and lasted up to the 1944 A.D. eruption, characterized by a near continuous effusive/explosive activity. For both periods we identify a correlation between Sr-isotopical features of magmas and their crystallization depth. In particular, we show that pyroxenes have Sr-isotopic ratios lower than 0.7074 and an equilibrium crystallization depth of 22-11 km. Moreover feldspars have higher 87Sr/86Sr values (0.7075-7 and an equilibrium crystallization depth of about 4 km. Therefore the most radiogenic magmas did not derive from a deeper reservoir but their higher Sr-isotopic ratios have been acquired at a shallower depth likely by crustal contamination

  18. Petrogenesis of Miocene alkaline volcanic suites from western Bohemia. Whole rock geochemistry and Sr-Nd-Pb isotopic signatures.

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Krmíček, Lukáš; Tomek, Č.; Lloyd, F. E.; Ladenberger, A.; Ackerman, Lukáš; Balogh, K.

    2016-01-01

    Roč. 76, č. 1 (2016), s. 77-93 ISSN 0009-2819 Institutional support: RVO:67985831 Keywords : Bohemian Massif * Cenozoic alkaline volcanism * Geochemistry * K-Ar ages * Sr-Nd-Pb isotopes Subject RIV: DD - Geochemistry Impact factor: 1.380, year: 2016

  19. The origin of the Merensky cyclic unit: Sr-isotopic and mineralogical evidence for an alternative orthomagmatic model

    International Nuclear Information System (INIS)

    Kruger, F.J.

    1992-02-01

    Mineralogical, Sr-isotopic and field data on the Critical and Main Zones of the Bushveld Complex indicate that the major input of magma at the Merensky level was fundamentally different to the resident magma. The data indicate that the new magma was more evolved and probably compositionally and thermally denser than the resident magma. This implies that the influxes were of a 'fountain' type, and involved the input of cool dense 'gabbroic' magma with a high Sr-isotopic initial ratio into the chamber containing warm buoyant 'noritic' magma with a lower initial ratio. The first fountain of magma entrained and mixed with the resident magma in the chamber, and the blended liquid then flowed along the interface between the resident and the crystalline floor. This cooler magma fountain resulted in the evolution of the two phase blobs as well as immiscible sulphide from the overlaying warmer liquid. These plunged through the new liquid layer to form the Merensky Reef. 37 refs., 5 figs., 1 tab

  20. High-precision Al-Mg isotopic systematics in USNM 3898 - The benchmark "ALL" for initial 87Sr/86Sr in the earliest Solar System

    Science.gov (United States)

    MacPherson, G. J.; Defouilloy, C.; Kita, N. T.

    2018-06-01

    The Allende CAI USNM 3898 is the basis for "ALL", the lowest measured initial 87Sr/86Sr value in any solar system material including other CAIs (Gray et al., 1973). If the value ALL is correct (debated), then USNM 3898 must be 1-2 million years older than other CAIs (Podosek et al., 1991). This would require in turn that it have a much higher initial 26Al/27Al value than other CAIs, on the order of 4 × 10-4. Podosek et al. (1991) showed that this is not the case, with initial 26Al/27Al = (4.5 ± 0.7) × 10-5, but their Mg-isotopic data had large error bars and there was clear isotopic disturbance in the data having the highest 27Al/24Mg. Without the latter data, the slope of their isochron is higher (5.10 ± 1.19) × 10-5) and within (large) error of being supracanonical. We used high-precision SIMS to re-determine the initial 26Al/27Al in this CAI and obtained a value of (5.013 ± 0.099) × 10-5, with an intercept δ26Mg* = - 0.008 ± 0.048 and MSWD = 1.3. This value is indistinguishable from that measured in many other CAIs and conclusively shows that USNM 3898 is not uniquely ancient. We also confirmed evidence of later isotopic disturbance, similar to what Podosek et al. found, indicating a re-melting and evaporation event some 200,000 years after initial CAI solidification.

  1. Multiple isotopes (O, C, Li, Sr) as tracers of CO2 and brine leakage from CO2-enhanced oil recovery activities in Permian Basin, Texas, USA

    Science.gov (United States)

    Phan, T. T.; Sharma, S.; Gardiner, J. B.; Thomas, R. B.; Stuckman, M.; Spaulding, R.; Lopano, C. L.; Hakala, A.

    2017-12-01

    Potential CO2 and brine migration or leakage into shallow groundwater is a critical issue associated with CO2 injection at both enhanced oil recovery (EOR) and carbon sequestration sites. The effectiveness of multiple isotope systems (δ18OH2O, δ13C, δ7Li, 87Sr/86Sr) in monitoring CO2 and brine leakage at a CO2-EOR site located within the Permian basin (Seminole, Texas, USA) was studied. Water samples collected from an oil producing formation (San Andres), a deep groundwater formation (Santa Rosa), and a shallow groundwater aquifer (Ogallala) over a four-year period were analyzed for elemental and isotopic compositions. The absence of any change in δ18OH2O or δ13CDIC values of water in the overlying Ogallala aquifer after CO2 injection indicates that injected CO2 did not leak into this aquifer. The range of Ogallala water δ7Li (13-17‰) overlaps the San Andres water δ7Li (13-15‰) whereas 87Sr/86Sr of Ogallala (0.70792±0.00005) significantly differs from San Andres water (0.70865±0.00003). This observation demonstrates that Sr isotopes are much more sensitive than Li isotopes in tracking brine leakage into shallow groundwater at the studied site. In contrast, deep groundwater δ7Li (21-25‰) is isotopically distinct from San Andres produced water; thus, monitoring this intermitted formation water can provide an early indication of CO2 injection-induced brine migration from the underlying oil producing formation. During water alternating with gas (WAG) operations, a significant shift towards more positive δ13CDIC values was observed in the produced water from several of the San Andres formation wells. The carbon isotope trend suggests that the 13C enriched injected CO2 and formation carbonates became the primary sources of dissolved inorganic carbon in the area surrounding the injection wells. Moreover, one-way ANOVA statistical analysis shows that the differences in δ7Li (F(1,16) = 2.09, p = 0.17) and 87Sr/86Sr (F(1,18) = 4.47, p = 0.05) values of

  2. Use of Pb and Sr isotopes on the determination of lead mineralization sources from Ribeira valley - Sao Paulo and Parana states

    International Nuclear Information System (INIS)

    Tassinari, C.C.G.; Barbour, A.P.; Sato, K.; Daitx, E.C.

    1990-01-01

    A lead and strontium isotope study was carried out on galena, barite and calcite from Pb-Ag syngenetic stratiform (Perau type) and hydrothermal veins (Panela type) deposits from Vale do Ribeira region (Sao Paulo and Parana states). The leads from the Perau and Panelas type deposits have respectively isotope ratios (sup(206)Pb/ sup(204)Pb 16.157 to 16.505 amd 16.520 to 17.273; sup(207)Pb/ sup(204)Pb = 15.466 to 15.720 and 15.470 to 15.780 and sup(208)Pb/ sup(204)Pb = 36.370 to 36.763 and 37.043 to 38.243), that defined a Stacey and Kramers model ages mainly concentrate within 1.7-1.5Ga. A review of published Pb isotopic compositions for these deposits and considerations of new Sr isotope data and Pb results using plumbotectonics model, indicate that the Perau type mineralizations are related to the syngenetic process and the Pb are derived from upper crust with a short crustal residence time. For the Panelas type deposits the Pb and Sr isotope studies support the conclusion that the ores were emplaced during regional metamorphism and the Pb were derived from lithologically complex source which may include metasedimentary and basement rocks. (author)

  3. The dynamics of central Main Ethiopian Rift waters: Evidence from {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr ratios

    Energy Technology Data Exchange (ETDEWEB)

    Rango, Tewodros, E-mail: tewodros.godebo@duke.edu [Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708 (United States)] [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia); Petrini, Riccardo; Stenni, Barbara [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Bianchini, Gianluca [Istituto di Geoscienze e Georisorse-CNR, Pisa (Italy)] [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Slejko, Francesca [University of Trieste, Department of Geosciences, Via Weiss 1, I-34100 Trieste (Italy); Beccaluva, Luigi [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Ayenew, Tenalem [Addis Ababa University, Department of Earth Sciences, P.O. Box 1176, Addis Ababa (Ethiopia)

    2010-12-15

    Research highlights: {yields} Chemical and isotope ({delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr) techniques are applied to understand various hydrological processes in the Main Ethiopian Rift. {yields} Some of the studied groundwaters display a depleted {delta}D-{delta}{sup 18}O composition when compared to the present-day average precipitation, thus suggesting that the rift floor aquifers also contains paleo-meteoric waters recharge associated with deep flow system. {yields} The pristine waters coming from the highlands display isotopic compositions characterized by less radiogenic {sup 87}Sr/{sup 86}Sr (and more depleted {delta}D, {delta}{sup 18}O). This isotopic signature subsequently evolves towards higher {sup 87}Sr/{sup 86}Sr by an interaction with the more radiogenic rhyolites of the rift and their weathered and redeposited products. - Abstract: Water samples from cold and geothermal boreholes, hot springs, lakes and rivers were analyzed for {delta}D, {delta}{sup 18}O and {sup 87}Sr/{sup 86}Sr compositions in order to investigate lake water-groundwater mixing processes, water-rock interactions, and to evaluate groundwater flow paths in the central Main Ethiopian Rift (MER) of the Ziway-Shala basin. Different ranges of isotopic values were recorded for different water types: hot springs show {delta}{sup 18}O -3.36 to +3.69 and {delta}D -15.85 to +24.23, deep Aluto-Langano geothermal wells show {delta}{sup 18}O -4.65 to -1.24 and {delta}D -12.39 to -9.31, groundwater wells show {delta}{sup 18}O -3.99 to +5.14 and {delta}D -19.69 to +32.27, whereas the lakes show {delta}{sup 18}O and {delta}D in the range +3.98 to +7.92 and +26.19 to +45.71, respectively. The intersection of the Local Meteoric Water Line (LMWL: {delta}D = 7 {delta}{sup 18}O + 11.2, R{sup 2} = 0.94, n = 42) and the Local Evaporation Line (LEL: {delta}D = 5.63{delta}{sup 18}O + 8, n = 14, R{sup 2} = 0.82) was used to estimate the average isotopic composition of recharge water into the

  4. Isotope geochemistry of recent magmatism in the Aegean arc: Sr, Nd, Hf, and O isotopic ratios in the lavas of Milos and Santorini-geodynamic implications

    Science.gov (United States)

    Briqueu, L.; Javoy, M.; Lancelot, J.R.; Tatsumoto, M.

    1986-01-01

    In this comparative study of variations in the isotopic compositions (Sr, Nd, O and Hf) of the calc-alkaline magmas of the largest two volcanoes, Milos and Santorini, of the Aegean arc (eastern Mediterranean) we demonstrate the complexity of the processes governing the evolution of the magmas on the scale both of the arc and of each volcano. On Santorini, the crustal contamination processes have been limited, effecting the magma gradually during its differentiation. The most differentiated lavas (rhyodacite and pumice) are also the most contaminated. On Milos, by contrast, these processes are very extensive. They are expressed in the 143Nd/144Nd vs. 87Sr/86Sr diagram as a continuous mixing curve between a mantle and a crustal end member pole defined by schists and metavolcanic rocks outcropping on these volcanoes. In contrast with Santorini, the least differentiated lavas on Milos are the most contaminated. These isotopic singularities can be correlated with the geodynamic evolution of the Aegean subduction zone, consisting of alternating tectonic phases of distension and compression. The genesis of rhyolitic magmas can be linked to the two phases of distension, and the contamination of the calc-alkaline mantle-derived magmas with the intermediate compressive phase. The isotopic characteristics of uncontaminated calc-alkaline primitive magmas of Milos and Santorini are directly comparable to those of magmas generated in subduction zones for which a contribution of subducted sediments to partial melts from the mantle is suggested, such as in the Aleutian, Sunda, and lesser Antilles island arcs. However, in spite of the importance of the sediment pile in the eastern Mediterranen oceanic crust (6-10 km), the contribution of the subducted terrigenous materials remains of limited amplitude. ?? 1986.

  5. APPLICATION OF O-H-B-Sr ISOTOPE SYSTEMATICS TO THE EXPLORATION OF SALINIZATION AND FLUSHING IN COASTAL AQUIFERS : PRELIMINARY DATA FROM THE PIALASSA BAIONA ECOSYSTEM (ADRIATIC SEA

    Directory of Open Access Journals (Sweden)

    Riccardo Petrini

    2009-07-01

    Full Text Available O, H, B and Sr isotopes were identified from surface-waters, ground-waters and waters percolating in soils at the Pialassa Baiona lagoon and nearby inland areas. The preliminary data demonstrate the occurrence of both conservative mixtures between seawater and freshwaters and cation exchange at the salt/fresh water interface during the intrusion. The O and H isotopes indicate that the freshwater component in the binary mixing had the isotopic features of the rainwater from Apennine catchments. Coupled O-H-B isotopes also show that the major contribution of the moving seawater was confined to the deeper aquifers and some of the soil waters. The Sr isotopes highlight the role of cation exchanges when seawater flushes freshwater aquifers, and allow the recognition of the different components of the solute. Deviations from these processes as revealed by B isotopes are interpreted as the evidence of possible anthropogenic inputs.

  6. Slab-derived components in the subcontinental lithospheric mantle beneath Chilean Patagonia: Geochemistry and Sr-Nd-Pb isotopes of mantle xenoliths and host basalt

    Science.gov (United States)

    Jalowitzki, Tiago; Gervasoni, Fernanda; Conceição, Rommulo V.; Orihashi, Yuji; Bertotto, Gustavo W.; Sumino, Hirochika; Schilling, Manuel E.; Nagao, Keisuke; Morata, Diego; Sylvester, Paul

    2017-11-01

    In subduction zones, ultramafic xenoliths hosted in alkaline basalts can yield significant information about the role of potential slab-derived components in the subcontinental lithospheric mantle (SCLM). Chemical and isotopic heterogeneities in such xenoliths are usually interpreted to reflect melt extraction followed by metasomatic re-enrichment. Here we report new whole-rock major, trace element and isotopic (Sr-Nd-Pb) data for a Proterozoic suite of 17 anhydrous spinel-lherzolites and Eocene (new K-Ar data) host alkaline basalt found near Coyhaique ( 46°S), Aysén Region, Chile. These Patagonian nodules are located in a current back-arc position, 100 km east of the present day volcanic arc and 320 km from the Chile Trench. The mantle xenoliths consist of coarse- to medium-grained spinel-lherzolites with trace element compositions characteristic of a subduction zone setting, such as pronounced negative Nb, Ta and Ti anomalies coupled with significant enrichment of LILEs (e.g., U) and chalcophile elements (W, Pb and Sn). Most of them are characterized by flat to depleted light-rare earth element (LREE) patterns (Ce/YbN = 0.6-1.1) coupled with less radiogenic Sr-Pb (87Sr/86Sr = 0.702422-0.703479; 206Pb/204Pb = 18.212-18.539) and more radiogenic Nd isotopic compositions (143Nd/144Nd = 0.512994-0.513242), similar to the depleted mantle component (DMM or PREMA). In contrast, samples with slight LREE enrichment (Ce/YbN = 1.3-1.8) show more radiogenic Sr-Pb (87Sr/86Sr = 0.703791-0.704239; 206Pb/204Pb = 18.572-18.703) and less radiogenic Nd isotopic compositions (143Nd/144Nd = 0.512859-0.512934), similar to the EM-2 reservoir. These new geochemical and isotope data suggest that the Coyhaique spinel-lherzolites are derived from a heterogeneous SCLM resulting from mixing between a depleted mantle component and up to 10% of slab-derived components. The enriched component added to the SCLM represents variable extents of melts of both subducted Chile Trench sediments and

  7. Considerations on the age of the Bambui Group (MG, Brazil) based on isotopic analyses of Sr and Pb

    International Nuclear Information System (INIS)

    Couto, J.G.P.; Cordani, U.G.; Kawashita, K.

    1981-01-01

    Based on radiometric ages, the Bambui Group deposition time is related to the end of the Precambrian. However, the ages determined and released through scientific magazines are mot in agreement (600-1350 m.y.) and many doubts about the geochrological picture of this important lithostratigraphic unit remained for a long time. As a result of the work developed by Metamig, CPGeo (IG-USP) and IPEN (SP), Rb/Sr and Pb/Pb isotopic determinations were done on 31 rocks samples and 17 galenas collected from the Bambui Basin distributed in Minas Gerais State. The Rb/Sr ages of 590 m.y. for Pirapora Formation, 620 m.y. for Tres Marias Formation, and 640 m.y. for the Paraopeba Formation situated in the stable area are linked to sedimentation processes. In the Paracatu region the age of 680 m.y. found for the Paraopeba Formation is related to metamorphic events. The lead isotopic ratios from the galenas suggest an isotopic evolution in two stages. The first ended with the lead separation from the mantle and its incorporation to the crust during events of the Transamazonic Cycle. The second ended when the lead were incorporated to the galenas and seems to be related to one or more events of the Brazilian Cycle. (Author) [pt

  8. Accurate mass measurements on neutron-deficient krypton isotopes

    CERN Document Server

    Rodríguez, D.; Äystö, J.; Beck, D.; Blaum, K.; Bollen, G.; Herfurth, F.; Jokinen, A.; Kellerbauer, A.; Kluge, H.-J.; Kolhinen, V.S.; Oinonen, M.; Sauvan, E.; Schwarz, S.

    2006-01-01

    The masses of $^{72–78,80,82,86}$Kr were measured directly with the ISOLTRAP Penning trap mass spectrometer at ISOLDE/CERN. For all these nuclides, the measurements yielded mass uncertainties below 10 keV. The ISOLTRAP mass values for $^{72–75}$Kr being more precise than the previous results obtained by means of other techniques, and thus completely determine the new values in the Atomic-Mass Evaluation. Besides the interest of these masses for nuclear astrophysics, nuclear structure studies, and Standard Model tests, these results constitute a valuable and accurate input to improve mass models. In this paper, we present the mass measurements and discuss the mass evaluation for these Kr isotopes.

  9. Ca biogeochemical cycle at the beech tree - soil solution interface from the Strengbach CZO (NE France): a clue from stable Ca and radiogenic Sr isotopes

    Science.gov (United States)

    Schmitt, Anne-Désirée; Gangloff, Sophie; Labolle, François; Chabaux, François; Stille, Peter

    2017-04-01

    Stable calcium and radiogenic Sr are analysed in several organs from two beech trees that were collected in June and September in the Strengbach CZO (NE France) and in corresponding soil solutions. The combination of these two isotopic systems shows that the isotopic signatures of roots are dominated by Ca fractionation mechanisms and Sr, and thus Ca, source variations. In contrast, translocation mechanisms are only governed by Ca fractionation processes. This study also confirms in the field that the Ca uptake mechanisms from nutritive solutions are controlled by adsorption processes in small roots because of physico-chemical mechanisms. Similarly, a study of surface soil solutions suggests that recent soil waters are less affected by vegetation uptake than in the past, probably because of a decline in the growth of the vegetation that is linked to climate warming, which causes drought episodes. Thus, soil solutions reflect the role of soil components in addition to nutrient uptake by vegetation. This isotopic Ca-Sr study also helps to identify one-time events that are caused by snow cover melting and/or dry episodes that release cations.

  10. Provenance of cryoconite deposited on the glaciers of the Tibetan Plateau: new insights from Nd-Sr isotopic composition and size distribution

    Science.gov (United States)

    Dong, Z.

    2016-12-01

    This study presents the Nd-Sr isotopic compositions and size distributions of cryoconite deposited on the glaciers at different locations on the Tibetan Plateau, in order to trace its source areas and the provenance of long-range transported (LRT) Asian dust on the Tibetan Plateau. The result of SEM-EDS analysis indicated that mineral dust particles were dominant in the cryoconite. Most of the cryoconite samples from the Tibetan Plateau indicated different Sr and Nd isotopic composition compared with sand from large deserts (e.g., the Taklimakan and Qaidam deserts). Some cryoconite samples showed very similar Nd-Sr isotopic ratios compared with those of nearby glacier basins (e.g., at Laohugou Glacier No.12, Dongkemadi Glacier and Shiyi Glacier), indicating the potential input of local crustal dust to cryoconite. The volume-size distribution for the cryoconite particles also indicated bi-modal distribution graphs with volume median diameters ranging from 0.57 to 20 μm and from 20 to 100 μm, demonstrating the contribution of both LRT Asian dust and local dust inputs to cryoconite. Based on the particle size distribution, we calculated a mean number ratio of local dust contribution to cryoconite ranging from 0.7% (Baishui Glacier No.1) to 17.6% (Shiyi Glacier) on the Tibetan Plateau. In general, the marked difference in the Nd-Sr isotopic ratios of cryoconite compared with those of large deserts probably indicates that, materials from the western deserts have not been easily transported to the hinterland of Tibetan Plateau by the Westerlies under the current climatic conditions, and the arid deserts on the Tibetan Plateau are the most likely sources for cryoconite deposition. The resistance of the Tibetan Plateau to the Westerlies may have caused such phenomena, especially for LRT eolian dust transported over the Tibetan Plateau. Thus, this work is of great importance in understanding the large scale eolian dust transport and climate over the Tibetan Plateau.

  11. 230Th-238U radioactive disequilibria in tholeiites from the FAMOUS zone (Mid-Atlantic Ridge, 36050'N): Th and Sr isotopic geochemistry

    International Nuclear Information System (INIS)

    Condomines, M.; Morand, P.; Allegre, C.J.

    1981-01-01

    We analyzed, U, Th and 230 Th/ 232 Th activity ratios for a few tholeiites from the Mid-Atlantic Ridge FAMOUS zone at 36 0 50'N. The results show a fairly wider scatter for both Th/U and ( 230 Th/ 232 Th) ratios. Seawater contamination appears to be responsible for this scatter and, for the uranium, produces an increase in content yielding a ( 234 U/ 238 U) ratio greater than 1 and, for the Th, an increase of the ( 230 Th/ 232 Th) ratio which is a very sensitive indicator for contamination. Also, the latter often is selective: U, Th and Sr are not affected in the same manner. When discarding all data for contaminated samples, the FAMOUS zone appears to be very homogeneous with a Th/U ratio value of 3.05 and a ( 230 Th/ 232 Th) ratio value of 1.24. Comparison with other active volcanic areas reveals a negative correlation between ( 230 Th/ 232 Th) and 87 Sr/ 86 Sr ratios for present lavas which is indicative of a consistency in Th-U and Rb-Sr fractionation in the source regions of these magmas. The Th isotopic geochemistry can thus provide useful information for the study of present volcanism, information as valuable as that from Sr, Pb or Nd isotopes. (orig.)

  12. Reexamination of the source material of acid igneous rocks, based on the selected Sr isotopic data

    International Nuclear Information System (INIS)

    Kagami, Hiroo; Shuto, Kenji; Gorai, Masao

    1975-01-01

    The relation between the ages and the initial strontium isotopic compositions obtained from acid igneous rocks by the whole-rock isochron method is re-examined, on the basis of the selected data. The points based on the data having high values of standard deviation (on the isochrons) show considerable scattering. This is probably ascribed to admixture of sialic materials, or secondary alteration and other geologic causes. The points based on the data having lower values of standard deviation (sigma value: 0.0001 - 0.0019), on the other hand, are evidently plotted within a narrow region just above the presumed Sr evolutional region of the source material of oceanic tholeiites. It is noteworthy that the former region meets the latter region at an earlier stage of the evolutional history of the earth (about 40 x 10 8 yrs. ago or older). It may be conceivable that the former region is the Sr evolutional region of the source material of acid igneous rocks. Considering from the inclination of the above Sr evolutional region, the source material of most of acid igneous rocks may possibly be a certain basic material, chemically similar to the continental tholeiitic basalts or basaltic andesites. On the other hand, the source material of a few acid igneous rocks with low initial strontium isotopic ratios may be a certain basic material resembling the oceanic tholeiites. Another possibility is that these acid igneous rocks and oceanic tholeiites may have been formed, under different physical conditions, directly from a certain common source material presumably of peridotitic composition. (auth.)

  13. Ca, Sr, Mo and U isotopes evidence ocean acidification and deoxygenation during the Late Permian mass extinction

    Science.gov (United States)

    Silva-Tamayo, Juan Carlos; Payne, Jon; Wignall, Paul; Newton, Rob; Eisenhauer, Anton; Weyer, Stenfan; Neubert, Nadja; Lau, Kim; Maher, Kate; Paytan, Adina; Lehrmann, Dan; Altiner, Demir; Yu, Meiyi

    2014-05-01

    The most catastrophic extinction event in the history of animal life occurred at the end of the Permian Period, ca. 252 Mya. Ocean acidification and global oceanic euxinia have each been proposed as causes of this biotic crisis, but the magnitude and timing of change in global ocean chemistry remains poorly constrained. Here we use multiple isotope systems - Ca, Sr, Mo and U - measured from well dated Upper Permian- Lower Triassic sedimentary sections to better constrain the magnitude and timing of change in ocean chemistry and the effects of ocean acidification and de-oxygenation through this interval. All the investigated carbonate successions (Turkey, Italy and China) exhibit decreasing δ44/40Ca compositions, from ~-1.4‰ to -2.0‰ in the interval preceding the main extinction. These values remain low during most of the Griesbachian, to finally return to -1.4‰ in the middle Dienerian. The limestone succession from southern Turkey also displays a major decrease in the δ88/86Sr values from 0.45‰ to 0.3‰ before the extinction. These values remain low during the Griesbachian and finally increase to 0.55‰ by the middle Dienerian. The paired negative anomalies on the carbonate δ44/40Ca and δ88/86Sr suggest a decrease in the carbonate precipitation and thus an episode of ocean acidification coincident with the major biotic crisis. The Mo and U isotope records also exhibit significant rapid negative anomalies at the onset of the main extinction interval, suggesting rapid expansion of anoxic and euxinic marine bottom waters during the extinction interval. The rapidity of the isotope excursions in Mo and U suggests substantially reduced residence times of these elements in seawater relative to the modern, consistent with expectations for a time of widespread anoxia. The large C-isotope variability within Lower Triassic rocks, which is similar to that of the Lower-Middle Cambrian, may reflect biologically controlled perturbations of the oceanic carbon cycle

  14. Sr, Nd, Pb and Hf isotopic constraints on mantle sources and crustal contaminants in the Payenia volcanic province, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin; Thirlwall, Matthew F.

    2015-01-01

    The presented Sr, Nd, Hf and double-spike Pb-isotopic analyses of Quaternary basalts from the Payenia volcanic province in southern Mendoza, Argentina, confirm the presence of two distinct mantle types feeding the Payenia volcanism. The southern Payenia mantle source feeding the intraplate-type Río...

  15. Sr-Pb-Nd isotopic evidence that both MORB and OIB sources contribute to oceanic island arc magmas in Fiji

    International Nuclear Information System (INIS)

    Gill, J.B.

    1984-01-01

    Twenty-eight new Pb, 20 Sr, and 9 Nd isotopic compositions are presented for 32 rocks and one galena from Fiji and the South Fiji (back-arc) Basin. The Fijian rocks range in age from 35 to 143 Nd/ 144 Nd and low 206 Pb/ 204 Pb). Nearly constant 207 Pb/ 204 Pb, and an OIB source component lying within the conventional Sr-Nd-Pb mantle array. In later calc-alkaline and shoshonitic series rocks, these same trace element and isotopic ratios are more like those of OIB. The change was not accompanied by an increase in 207 Pb/ 204 Pb or Cs/K, indeed, 207 Pb/ 204 Pb is closer to the mantle array in these later series. Consequently, the change indicates a greater contribution from OIB sources, rather than from recycled ocean crust. These interpretations require that both MORB and OIB sources coexist in the uppermost mantle above subducted lithosphere. (orig./WB)

  16. Method to make accurate concentration and isotopic measurements for small gas samples

    Science.gov (United States)

    Palmer, M. R.; Wahl, E.; Cunningham, K. L.

    2013-12-01

    Carbon isotopic ratio measurements of CO2 and CH4 provide valuable insight into carbon cycle processes. However, many of these studies, like soil gas, soil flux, and water head space experiments, provide very small gas sample volumes, too small for direct measurement by current constant-flow Cavity Ring-Down (CRDS) isotopic analyzers. Previously, we addressed this issue by developing a sample introduction module which enabled the isotopic ratio measurement of 40ml samples or smaller. However, the system, called the Small Sample Isotope Module (SSIM), does dilute the sample during the delivery with inert carrier gas which causes a ~5% reduction in concentration. The isotopic ratio measurements are not affected by this small dilution, but researchers are naturally interested accurate concentration measurements. We present the accuracy and precision of a new method of using this delivery module which we call 'double injection.' Two portions of the 40ml of the sample (20ml each) are introduced to the analyzer, the first injection of which flushes out the diluting gas and the second injection is measured. The accuracy of this new method is demonstrated by comparing the concentration and isotopic ratio measurements for a gas sampled directly and that same gas measured through the SSIM. The data show that the CO2 concentration measurements were the same within instrument precision. The isotopic ratio precision (1σ) of repeated measurements was 0.16 permil for CO2 and 1.15 permil for CH4 at ambient concentrations. This new method provides a significant enhancement in the information provided by small samples.

  17. The determination of B and Sr isotopes of quaternary biologic fossils in Yanghuzhuang Yanqing basin and their living environment

    International Nuclear Information System (INIS)

    Xiao Yingkai; Xiao Jun; Zhao Zhiqi; He Maoyong; Li Shizhen

    2007-01-01

    The B and Sr isotopic compositions of early Quaternary biologic fossils in Yanghuzhuang and living bivalves in Weishui river were measured. Comparing with the data of marine foraminifer, the results show a non-marine living environment for these foraminifers lived in early Quaternary in Yanghuzhuang, Yanqing; Basin. (authors)

  18. Evaluating the use of strontium isotopes in tree rings to record the isotopic signal of dust deposited on the Wasatch Mountains

    International Nuclear Information System (INIS)

    Miller, Olivia L.; Solomon, Douglas Kip; Fernandez, Diego P.; Cerling, Thure E.; Bowling, David R.

    2014-01-01

    Highlights: • Dust was a major contributor of Sr to soil and tree rings over Sr poor bedrocks. • Tree rings were evaluated for their use as a record of dust strontium isotope history. • The isotopic signal of dust deposited on the Wasatch Mountains changed over the past ∼75 years. - Abstract: Dust cycling from the Great Basin to the Rocky Mountains is an important component of ecological and hydrological processes. We investigated the use of strontium (Sr) concentrations and isotope ratios ( 87 Sr/ 86 Sr) in tree rings as a proxy for dust deposition. We report Sr concentrations and isotope ratios ( 87 Sr/ 86 Sr) from atmospherically deposited dust, soil, bedrock, and tree rings from the Wasatch Mountains to investigate provenance of dust landing on the Wasatch Mountains and to determine if a dust Sr record is preserved in tree rings. Trees obtained a majority of their Sr from dust, making them a useful record of dust source and deposition. Dust contributions of Sr to soils were more than 94% over quartzite, 63% over granodiorite, and 50% over limestone. Dust contributions of Sr to trees were more than 85% in trees growing over quartzite, 55% over granodiorite, and between 0% and 92% over limestone. These findings demonstrate that a dust signal was preserved in some tree rings and reflects how Sr from dust and bedrock mixes within the soil. Trees growing over quartzite were most sensitive to dust. Changes in Sr isotope ratios for a tree growing over quartzite were interpreted as changes in dust source over time. This work has laid the foundation for using tree rings as a proxy for dust deposition over time

  19. Man, nutrition and mobility: A comparison of teeth and bone from the Medieval era and the present from Pb and Sr isotopes

    International Nuclear Information System (INIS)

    Aberg, G.; Stray, H.; Fosse, G.

    1998-01-01

    Naturally occurring isotopic systems, such as strontium (Sr) and lead (Pb), are very useful for characterizing different sources and to produce background information. Norwegian teeth from the Medieval era have 206 Pb/ 204 Pb ratios between 18.8 and 18.2, in comparison with present day ratios of between 18.0 and 17.6 showing the impact of Pb from modern industrialization and from traffic. Sr analyses of Medieval teeth show that an individual living in a coastal town on the west coast of Norway can easily be distinguished from one in a rural area at that time. The Sr signature shows that Medieval people lived on local products while present people to a greater degree live on imported or domestic industrially processed food. Medieval and modern teeth from one site give similar Pb signatures and concentrations indicating no increase in pollution over time. However, the impact of industrial pollution can be seen from Pb analyses on contemporary teeth, so that the method can be used to monitor emission of heavy metals from local industry. Whilst the Pb and Sr natural isotopic systems individually provide valuable information, a combination of the two techniques is a very powerful tool in environmental and archaeological research. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  20. Isotopic geochemistry of Fernando de Noronha

    International Nuclear Information System (INIS)

    Gerlach, D.C.; Stormer, J.C. Jr.; Mueller, P.A.

    1987-01-01

    Volcanic and hybabyssal rocks ranging in age from 12 to 3 Ma from the Fernando de Noronha archipelago in the western equatorial Atlantic Ocean can generally be devided into two age-compositional groups that have variable and distinct isotopic compositions. Predominantly older alkali basalts and trachytes are generally characterized by more radiogenic Sr-isotopic ( 87 Sr/ 86 Sr=0.70457-0.70485) compositions and less radiogenic Nd-isotopic ( 143 Nd/ 144 Nd=0.51271-0.51281) and Pb-isotopic ( 206 Pb/ 204 Pb=19.132-19.282) compositions relative to the generally younger, more alkaline Si-undersaturated rocks which include nephelinites, ankaratrites, and melilitites ( 87 Sr/ 86 Sr=0.70365-0.70418, 143 Nd/ 144 Nd=0.51277-0.51290, 206 Pb/ 204 Pb=19.317-19.565). These variations suggest the influence of at least two separate components in the source(s) of both series. One component is characterized by high Rb/Sr and low μ, possibly derived from delaminated subcontinental lithosphere, whereas the other has high μ and low Rb/Sr similar to the source of St. Helena lavas. A third component is suggested by correlated compositions in the latest alkaline, Si-undersaturated lavas, and this component may be derived from depleted mantle. These isotopic variations in conjunction with the generally increasing degree of alkalinity with time are consistent with the temporal depletion of a low-μ, high Rb/Sr component and increasing contributions from a high-μ component in the source of the volcanic rocks of Fernando de Noronha. (orig.)

  1. Pb and Sr isotope measurements by inductively coupled plasma mass spectrometer: efficient time management for precision improvement

    Science.gov (United States)

    Monna, F.; Loizeau, J.-L.; Thomas, B. A.; Guéguen, C.; Favarger, P.-Y.

    1998-08-01

    One of the factors limiting the precision of inductively coupled plasma mass spectrometry is the counting statistics, which depend upon acquisition time and ion fluxes. In the present study, the precision of the isotopic measurements of Pb and Sr is examined. The time of measurement is optimally shared for each isotope, using a mathematical simulation, to provide the lowest theoretical analytical error. Different algorithms of mass bias correction are also taken into account and evaluated in term of improvement of overall precision. Several experiments allow a comparison of real conditions with theory. The present method significantly improves the precision, regardless of the instrument used. However, this benefit is more important for equipment which originally yields a precision close to that predicted by counting statistics. Additionally, the procedure is flexible enough to be easily adapted to other problems, such as isotopic dilution.

  2. Strontium stable isotope behaviour accompanying basalt weathering

    Science.gov (United States)

    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.

  3. Sr-isotope stratigraphy and dating of Neo-proterozoic carbonates and glacials from the northern and western parts of the Congo Craton

    International Nuclear Information System (INIS)

    Poidevin, J.L.

    2007-01-01

    Numerous occurrences of Neo-proterozoic carbonate platforms and glacigenic litho-facies are present around the Congo craton. They are especially well developed on its western and northern borders, i.e. in the fore-lands of the West Congo and Oubanguides belts. Sr isotopic stratigraphy enables us to characterize the deposition age of some carbonate units from these two domains. The 87 Sr/ 86 Sr isotopic ratios of limestones from the late 'Haut Shiloango' (0.7068) and the 'Schisto-calcaire' (0.7075) of the West-Congo domain are of post-Sturtian and post-Marinoan ages, respectively. The Lenda carbonates (0.7066) from the Northeast of the Democratic Republic of Congo and the limestones (0.7076) from the Bangui Basin, both in the Oubanguides fore-land, are of pre-Sturtian and post-Marinoan ages, respectively. These data associated with lithostratigraphic correlations allow us to ascribe the 'Bas Congo' lower mixtite (tillite) and the Akwokwo tillite (Lindian) to the Sturtian ice age. In the same way, the 'Bas Congo' upper mixtite (tillite) and the Bondo tillite (Bakouma Basin) are likely Marinoan in age. A new synthetic stratigraphy for these Neo-proterozoic domains is developed. (author)

  4. Methodological development for 87Sr/86Sr measurement in olive oil and preliminary discussion of its use for geographical traceability of PDO Nîmes (France).

    Science.gov (United States)

    Medini, Salim; Janin, Myriam; Verdoux, Patrick; Techer, Isabelle

    2015-03-15

    The lack of a geographical identification protocol for olive oils can lead to fraud and health risks. As some works call for Sr isotopes for the geographical identification of agri-food products, this study focus on the feasibility of extracting Sr from olive oils for isotopic measurements by TIMS. In fact, existing protocols for purification of Sr are unsuitable for lipid matrix. The defined protocol is applied to samples of PDO Nîmes olive oil. The accuracy of the extraction procedure is tested against isotopic standards. The values obtained are in conformity with NIST certified values. This consistency demonstrates that no modification of (87)Sr/(86)Sr ratio is brought about by this protocol. Consequently, the method is preliminary used on PDO Nîmes and Moroccan oils to evaluate the feasibility of a discriminant Sr signature on the two geographical products. This study provides promising results for the geographical discrimination and identification of PDO olive oils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Pb-Sr-Nd isotopic data of Indian Ocean ridges: New evidence of large-scale mapping of mantle heterogeneities

    International Nuclear Information System (INIS)

    Hamelin, B.; Dupre, B.; Allegre, C.J.

    1986-01-01

    A Pb-Sr-Nd isotope study of South West and East Indian Ridges confirms that the Indian Ocean belongs to a specific regional isotopic domain, as previously suggested by the results from islands of this ocean. The isotopic domain defined by the Indian MORB is indeed different from that of the North Atlantic and East Pacific Oceans. This demonstrates that the convective circulation of the upper mantle does not allow a rapid homogenization from one region to the other. The isotopic data of the Indian ridges can be interpreted by a contamination model, in which the depleted upper mantle (identical to that under the North Atlantic) is contaminated by two different types of contaminant, one corresponding to the source of the ''central Indian Ocean'' islands (Amsterdam, St. Paul, Marion, Prince Edward, Reunion, Rodriguez, Mauritius), and the other to a source similar to that of Walvis or Ninety East aseismic ridges. These two contaminants would have contributed to the ridge volcanism in different proportion over time. (orig.)

  6. Use of 1012 ohm current amplifiers in Sr and Nd isotope analyses by TIMS for application to sub-nanogram samples

    NARCIS (Netherlands)

    Koornneef, J.M.; Bouman, C.; Schwieters, J.B.; Davies, G.R.

    2013-01-01

    We have investigated the use of current amplifiers equipped with 10 12 ohm feedback resistors in thermal ionisation mass spectrometry (TIMS) analyses of sub-nanogram sample aliquots for Nd and Sr isotope ratios. The results of analyses using the 1012 ohm resistors were compared to those obtained

  7. Nd and Sr isotopes: implications of provenance and geological mapping; Isotopos de Nd e Sr: implicacoes de proveniencia e mapeamento geologico

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Marcio Fernando dos Santos; Horbe, Adriana Maria Coimbra; Dantas, Elton Luiz, E-mail: mgeoroots@gmail.com, E-mail: ahorbe@unb.br, E-mail: elton@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Instituto de Geociencias

    2015-07-01

    XRD, Nd and Sr isotopes, major, minor and traces elements quantification were applied to rocks, lateritic crusts and soils from Sumauma Supergroup and Alto Tapajos Group, in order to indicate provenance of the rocks and using lateritic products as geologic mapping tool. For the rocks, the results showed sources related to provinces Tapajos Parima, Rondonia Juruena, Sunsas, Carajas and Amazonia Central. However, the incision of Cachimbo graben allowed which the Sumauma Supergroup erosion also were source for the Alto Tapajos Group, allied to contribution of volcanics from Colider Group. Lateritic crusts and soils are correlates to bedrocks, allowing the use as geologic mapping tool. (author)

  8. Rapid Simultaneous Determination of 89Sr and 90Sr in Milk: A Procedure Using Cerenkov and Scintillation Counting

    International Nuclear Information System (INIS)

    2013-01-01

    Since 2004, the IAEA programme related to the terrestrial environment has included activities aimed at developing and testing a set of procedures for the determination of radionuclides in environmental samples. Both 89Sr and 90Sr are fission products that can be, and have been, released to the environment during nuclear explosions and nuclear reactor accidents. Since strontium uptake from milk is an important pathway for incorporation of radioactive strontium into the human body, the rapid and accurate analysis of radioactive strontium isotopes in milk is of crucial importance in emergency situations in order to protect the public from radiation hazards. This report describes a new approach for the rapid determination of 89 Sr and 90Sr in milk using Cerenkov and scintillation counting methods that was tested and validated by the analysis of four spiked milk samples in terms of repeatability, reproducibility and trueness (relative bias) in accordance with ISO guidelines. The report also describes the calculation of the uncertainty budget. This research was proposed in 2007 at the Asia-Pacific regional meeting of the IAEA Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA) network. Several ALMERA network laboratories participated in the validation procedure by performing reproducibility tests. The resulting recommended procedure is designed to be of general use to a wide range of laboratories, including those in the ALMERA network. It is expected that this rapid method for determining 89 Sr and 90 Sr in milk will be useful in emergency conditions and for routine environmental monitoring of elevated levels of radioactivity

  9. Experimental autoabsorption curve 90Sr in SrCO3. Efficiency calculation to detection of 90Sr, 90Y and 90Sr + 90Y in a beta gas proportional counter

    International Nuclear Information System (INIS)

    Gasco, C.; Alvarez, A.

    1987-01-01

    Strontium-90 has been determined by radiochemical separation techniques in environmental samples. These techniques, of course, cannot separate the two strontium radionuclides from each other of from stable strontium. Consequently the end product of the chemical separation contains all strontium isotopes in SrCO 3 . The beta particules emitted by 90 Sr are absorbed by the SrCO 3 precipitate. This is the main source of error in the activity measurement. It has been prepared sources of 90 Sr in SrCO 3 in order to determinate the counting efficiency and autoabsorption curve. Also detection efficiencies have been calibrated using known activities of 90 Y and equilibrium mixture of 90 Sr+ 90 Y in the same geometry than our samples. The activity of 90 Sr by ingrowth of 90 Y has been calculated by our computer program. (author). 2 figs., 3 refs

  10. New sequential separation procedure for Sr, Nd and Pb isotope ratio measurement in geological material using MC-ICP-MS and TIMS

    Digital Repository Service at National Institute of Oceanography (India)

    Makishima, A.; Nath, B.N.; Nakamura, E.

    A new 3-step sequential separation chemistry for Sr, Nd and Pb from silicate samples, which is suitable for isotope analysis by MC-ICP-MS as well as TIMS, has been developed. The chemistry is designed to minimize the number of evaporation steps...

  11. Man, nutrition and mobility: A comparison of teeth and bone from the Medieval era and the present from Pb and Sr isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Aberg, G.; Stray, H. [Institute for Energy Technology, Box 40, N-2007 Kjeller (Norway); Fosse, G. [Department of Anatomy and Cell Biology, University of Bergen, N-5009 Bergen (Norway)

    1998-12-11

    Naturally occurring isotopic systems, such as strontium (Sr) and lead (Pb), are very useful for characterizing different sources and to produce background information. Norwegian teeth from the Medieval era have {sup 206}Pb/{sup 204}Pb ratios between 18.8 and 18.2, in comparison with present day ratios of between 18.0 and 17.6 showing the impact of Pb from modern industrialization and from traffic. Sr analyses of Medieval teeth show that an individual living in a coastal town on the west coast of Norway can easily be distinguished from one in a rural area at that time. The Sr signature shows that Medieval people lived on local products while present people to a greater degree live on imported or domestic industrially processed food. Medieval and modern teeth from one site give similar Pb signatures and concentrations indicating no increase in pollution over time. However, the impact of industrial pollution can be seen from Pb analyses on contemporary teeth, so that the method can be used to monitor emission of heavy metals from local industry. Whilst the Pb and Sr natural isotopic systems individually provide valuable information, a combination of the two techniques is a very powerful tool in environmental and archaeological research. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. Isotope exchange of molecular oxygen with oxygen of La0,7Sr0,3CoO3-δ

    International Nuclear Information System (INIS)

    Vdovin, G.K.; Kuzin, B.L.; Kurumchin, Eh.Kh.

    1991-01-01

    The exchange rate of the oxygen in La 0,7 Sr 0,3 CoO 3-δ has been measured by an isotopic exchange method at temperatures 620-1250 K and pressures 1.6-10 torr. The activation energy and the dependence of the exchange rate on pressures in gas have been defined. It is suggested that the knees on the temperature dependences of the exchange rate are attributed to the appearance of Co 2+ ions on the surface of the sample at elevated temperature as new centres of the exchange reaction. The activation energies of the adsorption and desorption processes on the La 0,7 Sr 0,3 CoO 3-δ surface have been estimated

  13. Dissolution of barite for the analysis of strontium isotopes and other chemical and isotopic variations using aqueous sodium carbonate

    Science.gov (United States)

    Breit, G.N.; Simmons, E.C.; Goldhaber, M.B.

    1985-01-01

    A simple procedure for preparing barite samples for chemical and isotopic analysis is described. Sulfate ion, in barite, in the presence of high concentrations of aqueous sodium carbonate, is replaced by carbonate. This replacement forms insoluble carbonates with the cations commonly in barite: Ba, Sr, Ca and Pb. Sulfate is released into the solution by the carbonate replacement and is separated by filtration. The aqueous sulfate can then be reprecipitated for analysis of the sulfur and oxygen isotopes. The cations in the carbonate phase can be dissolved by acidifying the solid residue. Sr can be separated from the solution for Sr isotope analysis by ion-exchange chromatography. The sodium carbonate used contains amounts of Sr which will affect almost all barite 87Sr 86Sr ratios by less than 0.00001 at 1.95?? of the mean. The procedure is preferred over other techniques used for preparing barite samples for the determination of 87Sr 86Sr ratios because it is simple, rapid and enables simultaneous determination of many compositional parameters on the same material. ?? 1985.

  14. Arsenic and other oxyanion-forming trace elements in an alluvial basin aquifer: Evaluating sources and mobilization by isotopic tracers (Sr, B, S, O, H, Ra)

    Energy Technology Data Exchange (ETDEWEB)

    Vinson, David S., E-mail: dsv3@duke.edu [Duke University, Division of Earth and Ocean Sciences, Box 90227, Durham, NC 27708 (United States); McIntosh, Jennifer C. [University of Arizona, Department of Hydrology and Water Resources, 1133 E. James E. Rogers Way, Tucson, AZ 85721 (United States); Dwyer, Gary S.; Vengosh, Avner [Duke University, Division of Earth and Ocean Sciences, Box 90227, Durham, NC 27708 (United States)

    2011-08-15

    Highlights: > Elevated natural As and F occur in the Willcox Basin aquifer of Arizona. > Oxyanion-forming elements are derived from volcanic-source aquifer sediments. > Sr isotopes trace sediment sources linked to oxyanion-forming trace elements. > {sup 87}Sr/{sup 86}Sr > 0.720 indicates Proterozoic crystalline-source sediment contributing low As. > Both sediment source and hydrogeochemical evolution (Ca/Na) affect As levels. - Abstract: The Willcox Basin is a hydrologically closed basin in semi-arid southeastern Arizona (USA) and, like many other alluvial basins in the southwestern USA, is characterized by oxic, near-neutral to slightly basic groundwater containing naturally elevated levels of oxyanion-forming trace elements such as As. This study evaluates the sources and mobilization of these oxyanionic trace elements of health significance by using several isotopic tracers of water-rock interaction and groundwater sources ({sup 87}Sr/{sup 86}Sr, {delta}{sup 34}S{sub SO4}, {delta}{sup 11}B, {delta}{sup 2}H, {delta}{sup 18}O, {sup 3}H). Values of {delta}{sup 2}H (-85 per mille to -64 per mille) and {delta}{sup 18}O (-11.8 per mille to -8.6 per mille) are consistent with precipitation and groundwater in adjacent alluvial basins, and low to non-detectable {sup 3}H activities further imply that modern recharge is slow in this semi-arid environment. Large variations in {sup 87}Sr/{sup 86}Sr ratios imply that groundwater has interacted with multiple sediment sources that constitute the basin-fill aquifer, including Tertiary felsic volcanic rocks, Paleozoic sedimentary rocks, and Proterozoic crystalline rocks. In general, low concentrations of oxyanion-forming trace elements and F{sup -} are associated with a group of waters exhibiting highly radiogenic values of {sup 87}Sr/{sup 86}Sr (0.72064-0.73336) consistent with waters in Proterozoic crystalline rocks in the mountain blocks (0.73247-0.75010). Generally higher As concentrations (2-29 {mu}g L{sup -1}), other

  15. Strontium isotopes reveal weathering processes in lateritic covers in southern China with implications for paleogeographic reconstructions

    Science.gov (United States)

    Wei, Xiao; Wang, Shijie; Ji, Hongbing; Shi, Zhenhua

    2018-01-01

    The isotope ratios of Sr are useful tracers for studying parent material sources, weathering processes, and biogeochemical cycling. Mineralogical and geochemical investigations of two lateritic weathering covers, in an area close to the Tropic of Cancer (Guangxi Province, southern China), were undertaken to study the regional weathering processes and Sr isotopic sources. We found that weathering and decomposition of Rb- and Sr-bearing minerals change the Sr isotopic composition in weathering products (lateritic soils). Weathering of illite lowered the 87Sr/86Sr ratio whereas dissolving and leaching of carbonate minerals increased the 87Sr/86Sr ratio. An Fe nodular horizon is widely developed on the top of the weathering covers in the studied area and it differs from the lateritic soil horizon in mineral composition, construction, and elemental concentration. Furthermore, both Fe2O3 and P2O5 (concentrations) are negatively correlated with the 87Sr/86Sr ratios, suggesting fixation of apatite by Fe oxides is a controlling factor of the Sr isotopic composition in the Fe nodular horizon. The 87Sr/86Sr and Nb/Sr ratios imply the contents and proportions of Fe nodules and clay are critical in controlling the changes of Sr isotopic composition in the Fe nodular horizon. The two stages of the weathering process of carbonate rocks are revealed by the87Sr/86Sr versus Nb/Sr diagram. The 87Sr/86Sr and Rb/Sr ratios suggest that Sr isotopes in the weathering covers within the studied area are derived mainly from parent rock weathering and that the contributions from allothogenic Sr isotopes are limited. A comparison of Sr isotopic composition signatures in the weathering covers of the studied area and Guizhou Province provided insight into the Sr isotopic source and paleogeographic evolution of southern China. From the Permian to the Triassic, the continental fragment sources of the South China sedimentary basin changed significantly. In the Permian, Southern China presented the

  16. Strontium isotopes reveal weathering processes in lateritic covers in southern China with implications for paleogeographic reconstructions.

    Directory of Open Access Journals (Sweden)

    Xiao Wei

    Full Text Available The isotope ratios of Sr are useful tracers for studying parent material sources, weathering processes, and biogeochemical cycling. Mineralogical and geochemical investigations of two lateritic weathering covers, in an area close to the Tropic of Cancer (Guangxi Province, southern China, were undertaken to study the regional weathering processes and Sr isotopic sources. We found that weathering and decomposition of Rb- and Sr-bearing minerals change the Sr isotopic composition in weathering products (lateritic soils. Weathering of illite lowered the 87Sr/86Sr ratio whereas dissolving and leaching of carbonate minerals increased the 87Sr/86Sr ratio. An Fe nodular horizon is widely developed on the top of the weathering covers in the studied area and it differs from the lateritic soil horizon in mineral composition, construction, and elemental concentration. Furthermore, both Fe2O3 and P2O5 (concentrations are negatively correlated with the 87Sr/86Sr ratios, suggesting fixation of apatite by Fe oxides is a controlling factor of the Sr isotopic composition in the Fe nodular horizon. The 87Sr/86Sr and Nb/Sr ratios imply the contents and proportions of Fe nodules and clay are critical in controlling the changes of Sr isotopic composition in the Fe nodular horizon. The two stages of the weathering process of carbonate rocks are revealed by the87Sr/86Sr versus Nb/Sr diagram. The 87Sr/86Sr and Rb/Sr ratios suggest that Sr isotopes in the weathering covers within the studied area are derived mainly from parent rock weathering and that the contributions from allothogenic Sr isotopes are limited. A comparison of Sr isotopic composition signatures in the weathering covers of the studied area and Guizhou Province provided insight into the Sr isotopic source and paleogeographic evolution of southern China. From the Permian to the Triassic, the continental fragment sources of the South China sedimentary basin changed significantly. In the Permian, Southern

  17. Automated Sample Preparation for Radiogenic and Non-Traditional Metal Isotopes: Removing an Analytical Barrier for High Sample Throughput

    Science.gov (United States)

    Field, M. Paul; Romaniello, Stephen; Gordon, Gwyneth W.; Anbar, Ariel D.; Herrmann, Achim; Martinez-Boti, Miguel A.; Anagnostou, Eleni; Foster, Gavin L.

    2014-05-01

    MC-ICP-MS has dramatically improved the analytical throughput for high-precision radiogenic and non-traditional isotope ratio measurements, compared to TIMS. The generation of large data sets, however, remains hampered by tedious manual drip chromatography required for sample purification. A new, automated chromatography system reduces the laboratory bottle neck and expands the utility of high-precision isotope analyses in applications where large data sets are required: geochemistry, forensic anthropology, nuclear forensics, medical research and food authentication. We have developed protocols to automate ion exchange purification for several isotopic systems (B, Ca, Fe, Cu, Zn, Sr, Cd, Pb and U) using the new prepFAST-MC™ (ESI, Nebraska, Omaha). The system is not only inert (all-flouropolymer flow paths), but is also very flexible and can easily facilitate different resins, samples, and reagent types. When programmed, precise and accurate user defined volumes and flow rates are implemented to automatically load samples, wash the column, condition the column and elute fractions. Unattended, the automated, low-pressure ion exchange chromatography system can process up to 60 samples overnight. Excellent reproducibility, reliability, recovery, with low blank and carry over for samples in a variety of different matrices, have been demonstrated to give accurate and precise isotopic ratios within analytical error for several isotopic systems (B, Ca, Fe, Cu, Zn, Sr, Cd, Pb and U). This illustrates the potential of the new prepFAST-MC™ (ESI, Nebraska, Omaha) as a powerful tool in radiogenic and non-traditional isotope research.

  18. Calcium biogeochemical cycle at the beech tree-soil solution interface from the Strengbach CZO (NE France): insights from stable Ca and radiogenic Sr isotopes

    Science.gov (United States)

    Schmitt, Anne-Désirée; Gangloff, Sophie; Labolle, François; Chabaux, François; Stille, Peter

    2017-09-01

    Calcium (Ca) is the fourth most abundant element in mineral nutrition and plays key physiological and structural roles in plant metabolism. At the soil-water-plant scale, stable Ca isotopes are a powerful tool for the identification of plant-mineral interactions and recycling via vegetation. Radiogenic Sr isotopes are often used as tracers of Ca sources and mixtures of different reservoirs. In this study, stable Ca and radiogenic Sr are combined and analysed in several organs from two beech trees that were collected in June and September in the Strengbach critical zone observatory (CZO) (NE France) and in corresponding soil solutions. At the beech-tree scale, this study confirms the field Ca adsorption (i.e., physico-chemical mechanism and not vital effects) on carboxyl acid groups of pectin in the apoplasm of small roots. The analysis of the xylem sap and corresponding organs shows that although the Strengbach CZO is nutrient-poor, Ca seems to be non-limiting for tree-growth. Different viscosities of xylem sap between the stemwood and branches or leaves can explain δ44/40Ca values in different tree-organs. The bark and phloem 40Ca-enrichments could be due to Ca-oxalate precipitation in the bark tissues and in the phloem. The results from this study regarding the combination of these two isotopic systems show that the isotopic signatures of the roots are dominated by Ca fractionation mechanisms and Sr, and thus Ca, source variations. In contrast, translocation mechanisms are only governed by Ca fractionation processes. This study showed that at the root-soil solution interface, litter degradation was not the main source of Ca and Sr and that the soil solutions are not the complement of uptake by roots for samples from the 2011/2013 period. The opposite is observed for older samples. These observations indicate the decreasing contribution of low radiogenic Sr fluxes, such as recycling, alimenting the soil solutions. Such reduced importance of nutrient uptake and

  19. Large-scale purification of 90Sr from nuclear waste materials for production of 90Y, a therapeutic medical radioisotope.

    Science.gov (United States)

    Wester, Dennis W; Steele, Richard T; Rinehart, Donald E; DesChane, Jaquetta R; Carson, Katharine J; Rapko, Brian M; Tenforde, Thomas S

    2003-07-01

    A major limitation on the supply of the short-lived medical isotope 90Y (t1/2 = 64 h) is the available quantity of highly purified 90Sr generator material. A radiochemical production campaign was therefore undertaken to purify 1,500 Ci of 90Sr that had been isolated from fission waste materials. A series of alkaline precipitation steps removed all detectable traces of 137Cs, alpha emitters, and uranium and transuranic elements. Technical obstacles such as the buildup of gas pressure generated upon mixing large quantities of acid with solid 90Sr carbonate were overcome through safety features incorporated into the custom-built equipment used for 90Sr purification. Methods are described for analyzing the chemical and radiochemical purity of the final product and for accurately determining by gravimetry the quantities of 90Sr immobilized on stainless steel filters for future use.

  20. Large-scale purification of 90Sr from nuclear waste materials for production of 90Y, a therapeutic medical radioisotope

    International Nuclear Information System (INIS)

    Wester, D.W.; Steele, R.T.; Rinehart, D.E.; DesChane, J.R.; Carson, K.J.; Rapko, B.M.; Tenforde, T.S.

    2003-01-01

    A major limitation on the supply of the short-lived medical isotope 90 Y (t 1/2 =64 h) is the available quantity of highly purified 90 Sr generator material. A radiochemical production campaign was therefore undertaken to purify 1500 Ci of 90 Sr that had been isolated from fission waste materials. A series of alkaline precipitation steps removed all detectable traces of 137 Cs, alpha emitters, and uranium and transuranic elements. Technical obstacles such as the buildup of gas pressure generated upon mixing large quantities of acid with solid 90 Sr carbonate were overcome through safety features incorporated into the custom-built equipment used for 90 Sr purification. Methods are described for analyzing the chemical and radiochemical purity of the final product and for accurately determining by gravimetry the quantities of 90 Sr immobilized on stainless steel filters for future use

  1. Formic acid hydrolysis/liquid chromatography isotope dilution mass spectrometry: An accurate method for large DNA quantification.

    Science.gov (United States)

    Shibayama, Sachie; Fujii, Shin-Ichiro; Inagaki, Kazumi; Yamazaki, Taichi; Takatsu, Akiko

    2016-10-14

    Liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) with formic acid hydrolysis was established for the accurate quantification of λDNA. The over-decomposition of nucleobases in formic acid hydrolysis was restricted by optimizing the reaction temperature and the reaction time, and accurately corrected by using deoxynucleotides (dNMPs) and isotope-labeled dNMPs as the calibrator and the internal standard, respectively. The present method could quantify λDNA with an expanded uncertainty of 4.6% using 10fmol of λDNA. The analytical results obtained with the present method were validated by comparing with the results of phosphate-base quantification by inductively coupled plasma-mass spectrometry (ICP-MS). The results showed good agreement with each other. We conclude that the formic acid hydrolysis/LC-IDMS method can quantify λDNA accurately and is promising as the primary method for the certification of DNA as reference material. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Petrogenesis of orogenic lamproites of the Bohemian Massif: Sr-Nd-Pb-Li isotope constraints for Variscan enrichment of ultra-depleted mantle domains

    Czech Academy of Sciences Publication Activity Database

    Krmíček, Lukáš; Romer, R. L.; Ulrych, Jaromír; Glodny, J.; Prelevič, D.

    2016-01-01

    Roč. 35, 1 July (2016), s. 198-216 ISSN 1342-937X Institutional support: RVO:67985831 Keywords : Silica-rich lamproites * Sr-Nb-Pb-Li isotopes * mantle metasomatism * Variscides Subject RIV: DB - Geology ; Mineralogy Impact factor: 6.959, year: 2016

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

    Science.gov (United States)

    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.

  4. A Rb-Sr isotope study of a young granite sheet at Marble Delta, southern Natal

    International Nuclear Information System (INIS)

    Naidoo, D.D.; Eglington, B.M.; Harmer, R.E.

    1989-01-01

    Rb-Sr isotope data are presented for two apophyses of a granite sheet intrusive into marble at Marble Delta, southern Natal. Granite samples collected near the margins of these apophyses contain calcite and are thought to have been contaminated by the marble during intrusion of the granite magma. In contrast, those further away from contacts lack calcite. The 'uncontaminated' granite samples define an isochron date of 899 ± 11 Ma. This data is thought to represent the intrusive age of the granite sheet. 11 refs., 5 figs., 2 tabs

  5. High-Precision In Situ 87Sr/86Sr Analyses through Microsampling on Solid Samples: Applications to Earth and Life Sciences

    Directory of Open Access Journals (Sweden)

    Sara Di Salvo

    2018-01-01

    Full Text Available An analytical protocol for high-precision, in situ microscale isotopic investigations is presented here, which combines the use of a high-performing mechanical microsampling device and high-precision TIMS measurements on micro-Sr samples, allowing for excellent results both in accuracy and precision. The present paper is a detailed methodological description of the whole analytical procedure from sampling to elemental purification and Sr-isotope measurements. The method offers the potential to attain isotope data at the microscale on a wide range of solid materials with the use of minimally invasive sampling. In addition, we present three significant case studies for geological and life sciences, as examples of the various applications of microscale 87Sr/86Sr isotope ratios, concerning (i the pre-eruptive mechanisms triggering recent eruptions at Nisyros volcano (Greece, (ii the dynamics involved with the initial magma ascent during Eyjafjallajökull volcano’s (Iceland 2010 eruption, which are usually related to the precursory signals of the eruption, and (iii the environmental context of a MIS 3 cave bear, Ursus spelaeus. The studied cases show the robustness of the methods, which can be also be applied in other areas, such as cultural heritage, archaeology, petrology, and forensic sciences.

  6. Isotopic compositions of Sr in waters and of Pb in sediments and ashes from an urban incinerator using an ICP-MS

    International Nuclear Information System (INIS)

    Fillion, N.; Clauer, N.; Samuen, J.

    1996-01-01

    The analytical precision of the Sr and the Pb isotopic compositions of natural samples obtained with a conventional ICP-MS is of 3 to 7 x 10 -3 (internal 2 σ) for the 87 Sr/ 86 Sr ratio, 6 to 8 x 10 -3 for the 206 Pb/ 207 Pb and 1 to 4 x 10 -1 for the 206 Pb/ 204 Pb and 207 Pb/ 204 Pb ratios. Such accuracy is obtained with a procedure including a resin-chromatographic purification, a correction with respect to standard values (NBS 987 and 981) and a routine of four determinations for each sample. This procedure should allow rapid geochemical investigations ahead of more precise determinations by thermo-ionization mass spectrometry. (authors). 8 refs., 6 figs., 5 tabs

  7. Sediment Sources, Depositional Environment, and Diagenetic Alteration of the Marcellus Shale, Appalachian Basin, USA: Nd, Sr, Li and U Isotopic Constraints

    Science.gov (United States)

    Phan, T. T.; Capo, R. C.; Gardiner, J. B.; Stewart, B. W.

    2017-12-01

    The organic-rich Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, is a major target of natural gas exploration. Constraints on local and regional sediment sources, depositional environments, and post-depositional processes are essential for understanding the evolution of the basin. In this study, multiple proxies, including trace metals, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U and Li isotopes were applied to bulk rocks and authigenic fractions of the Marcellus Shale and adjacent limestone/sandstone units from two locations separated by 400 km. The range of ɛNd values (-7.8 to -6.4 at 390 Ma) is consistent with a clastic sedimentary component derived from a well-mixed source of fluvial and eolian material of the Grenville orogenic belt. The Sm-Nd isotope system and bulk REE distributions appear to have been minimally affected by post-depositional processes, while the Rb-Sr isotope system shows evidence of limited post-depositional redistribution. While REE are primarily associated with silicate minerals (80-95%), REE patterns of sequentially extracted fractions reflect post-depositional alteration at the intergranular scale. Although the chemical index of alteration (CIA = 54 to 60) suggests the sediment source was not heavily weathered, Li isotope data are consistent with progressively increasing weathering of the source region during Marcellus Shale deposition. δ238U values in bulk shale and reduced phases (oxidizable fraction) are higher than those of modern seawater and upper crust. The isotopically heavy U accumulated in these authigenic phases can be explained by the precipitation of insoluble U in anoxic/euxinic bottom water. Unlike carbonate cement within the shale, the similarity between δ238U values and REE patterns of the limestone units and those of modern seawater indicates that the limestone formed under open ocean (oxic) conditions.

  8. Development of a fully automated open-column chemical-separation system—COLUMNSPIDER—and its application to Sr-Nd-Pb isotope analyses of igneous rock samples

    Science.gov (United States)

    Miyazaki, Takashi; Vaglarov, Bogdan Stefanov; Takei, Masakazu; Suzuki, Masahiro; Suzuki, Hiroaki; Ohsawa, Kouzou; Chang, Qing; Takahashi, Toshiro; Hirahara, Yuka; Hanyu, Takeshi; Kimura, Jun-Ichi; Tatsumi, Yoshiyuki

    A fully automated open-column resin-bed chemical-separation system, named COLUMNSPIDER, has been developed. The system consists of a programmable micropipetting robot that dispenses chemical reagents and sample solutions into an open-column resin bed for elemental separation. After the initial set up of resin columns, chemical reagents, and beakers for the separated chemical components, all separation procedures are automated. As many as ten samples can be eluted in parallel in a single automated run. Many separation procedures, such as radiogenic isotope ratio analyses for Sr and Nd, involve the use of multiple column separations with different resin columns, chemical reagents, and beakers of various volumes. COLUMNSPIDER completes these separations using multiple runs. Programmable functions, including the positioning of the micropipetter, reagent volume, and elution time, enable flexible operation. Optimized movements for solution take-up and high-efficiency column flushing allow the system to perform as precisely as when carried out manually by a skilled operator. Procedural blanks, examined for COLUMNSPIDER separations of Sr, Nd, and Pb, are low and negligible. The measured Sr, Nd, and Pb isotope ratios for JB-2 and Nd isotope ratios for JB-3 and BCR-2 rock standards all fall within the ranges reported previously in high-accuracy analyses. COLUMNSPIDER is a versatile tool for the efficient elemental separation of igneous rock samples, a process that is both labor intensive and time consuming.

  9. Isotopic evolution of Mauna Loa volcano

    International Nuclear Information System (INIS)

    Kurz, M.D.; Kammer, D.P.

    1991-01-01

    In an effort to understand the temporal helium isotopic variations in Mauna Loa volcano, we have measured helium, strontium and lead isotopes in a suite of Mauna Loa lavas that span most of the subaerial eruptive history of the volcano. The lavas range in age from historical flows to Ninole basalt which are thought to be several hundred thousand years old. Most of the samples younger than 30 ka in age (Kau Basalt) are radiocarbon-dated flows, while the samples older than 30 ka are stratigraphically controlled (Kahuku and Ninole Basalt). The data reveal a striking change in the geochemistry of the lavas approximately 10 ka before present. The lavas older than 10 ka are characterized by high 3 He/ 4 He (≅ 16-20 times atmospheric), higher 206 Pb/ 204 Pb (≅ 18.2), and lower 87 Sr/ 86 Sr(≅ 0.70365) ratios than the younger Kau samples (having He, Pb and Sr ratios of approximately 8.5 x atmospheric, 18.1 and 0.70390, respectively). The historical lavas are distinct in having intermediate Sr and Pb isotopic compositions with 3 He/ 4 He ratios similar to the other young Kau basalt (≅ 8.5 x atmospheric). The isotopic variations are on a shorter time scale (100 to 10,000 years) than has previously been observed for Hawaiian volcanoes, and demonstrate the importance of geochronology and stratigraphy to geochemical studies. The data show consistency between all three isotope systems, which suggests that the variations are not related to magma chamber degassing processes, and that helium is not decoupled from the other isotopes. However, the complex temporal evolution suggests that three distinct mantle sources are required to explain the isotopic data. Most of the Mauna Loa isotopic variations could be explained by mixing between a plume type source, similar to Loihi, and an asthenospheric source with helium isotopic composition close to MORB and elevated Sr isotopic values. (orig./WL)

  10. Rb-Sr, K-Ar, and stable isotope evidence for the ages and sources of fluid components of gold-bearing quartz veins in the northern Sierra Nevada foothills metamorphic belt, California

    Science.gov (United States)

    Böhlke, John Karl; Kistler, R. W.

    1986-01-01

    Gold-bearing quartz veins occur in and near major fault zones in deformed oceanic and island-arc rocks west of the main outcrop of the Sierra Nevada composite batholith. Veins typically occupy minor reverse faults that crosscut blueschist to amphibolite-grade metamorphic rocks whose metamorphic ages range from early Paleozoic to Jurassic. Vein micas and carbonate-quartz-mica assemblages that formed by hydrothermal metasomatism of ultramafic wall rocks in the Alleghany, Grass Valley, Washington, and Mother Lode districts yield concordant K-Ar and Rb-Sr ages. The dated veins are significantly younger than prograde metamorphism, penetrative deformation, and accretion of their host rocks to the continental margin. New and previously published mineralization ages from 13 localities in the Sierra foothills range from about 140 to 110 m.y. ago, with mean and median between 120 and 115 m.y. The age relations suggest that mineralizing fluids were set in motion by deep magmatic activity related to the resumption of east-dipping subduction along the western margin of North America following the Late Jurassic Nevadan collision event.CO 2 -bearing fluids responsible for metasomatism and much of the vein mica, carbonate, albite, and quartz deposition in several northern mines were isotopically heavy (delta 18 O [asymp] 8-14ppm; delta D between about -10 and -50ppm) and do not resemble seawater, magmatic, or meteoric waters. Metasomatic and vein-filling mica, dolomite, magnesite, and quartz in altered ultramafic rocks generally formed from fluids with similar Sr and O isotope ratios at a given locality. Consistent quartz-mica delta 18 O fractionations (delta 18 O (sub Q-M) = 4.5-4.9ppm) from various localities imply uniform equilibration temperatures, probably between 300 degrees and 350 degrees C. On a local (mine) scale, fluids responsible for both carbonate alteration of mafic and ultramafic wall rocks and albitic alteration of felsic and pelitic rocks had similar Sr isotope

  11. Pb, Sr, and Nd isotopic compositions of a suite of Large Archean, igneous rocks, eastern Beartooth Mountains - Implications for crust-mantle evolution

    Science.gov (United States)

    Wooden, J. L.; Mueller, P. A.

    1988-01-01

    Compositionally diverse Late Archean rocks (2.74-2.79 Ga old) from the eastern Beartooth Mountains (Montana and Wyoming) were studied and shown to have the same initial Pb, Sr, and Nd isotopic ratios. Lead and Sr initial ratios are higher and Nd initial values lower than predicted for rocks derived from model mantle sources and strongly indicate the involvement of an older crustal reservoir in the genesis of these rocks. A model involving subduction of continental detritus and contamination of the overlying mantle is suggested.

  12. Isotopic signature of Madeira basaltic magmatism

    International Nuclear Information System (INIS)

    Kogarko, L.N.; Karpenko, S.F.; Bibikova, E.V.; Mato, Zh.

    2000-01-01

    Chemical composition of the basalts of Madeira Island is studied. To assess the isotopic sources of magmatism the Pb-Sr, Sm-Nd, U-Th-Pb systems were investigated in a number of basalts. It is shown that the island's rocks are characterized by the mostly deplet sources in relation to Pb-Sr and Sm-Nd systems ( 87 Sr/ 86 Sr - 0.70282-0.70292, 143 Nd/ 144 Nd - 0.52303-0.51314). Isotopic composition of lead testifies that the magmatism reservoir is some enriched. It is concluded that the magmatism of Madeira Island is a new example of world ocean island's volcanism [ru

  13. Determination of the geographic origin of rice by chemometrics with strontium and lead isotope ratios and multielement concentrations.

    Science.gov (United States)

    Ariyama, Kaoru; Shinozaki, Miyuki; Kawasaki, Akira

    2012-02-22

    The objective of this study was to develop a technique for determining the country of origin of rice in the Japanese market. The rice samples included a total of 350 products grown in Japan (n = 200), the United States (n = 50), China (n = 50), and Thailand (n = 50). In this study, (87)Sr/(86)Sr and Pb isotope ((204)Pb, (206)Pb, (207)Pb, and (208)Pb) ratios and multielement concentrations (Al, Fe, Co, Ni, Cu, Rb, Sr, and Ba) were determined by high-resolution inductively coupled plasma mass spectrometry. By combining three chemometric techniques based on different principles and determination criteria, the countries of origin of rice were determined. The predictions made by 10-fold cross-validation were around 97% accurate. The presented method demonstrated the effectiveness of determining the geographic origin of an agricultural product by combining several chemometric techniques using heavy element isotope ratios and multielement concentrations.

  14. Onset of collectivity in neutron-rich Sr and Kr isotopes: Prompt spectroscopy after Coulomb excitation at REX-ISOLDE, CERN

    Directory of Open Access Journals (Sweden)

    Clément E.

    2013-12-01

    Full Text Available A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N = 60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

  15. Ion microprobe Sr isotope analysis of carbonates with about 5 μm spatial resolution: An example from an ayu otolith

    International Nuclear Information System (INIS)

    Sano, Yuji; Shirai, Kotaro; Takahata, Naoto; Amakawa, Hiroshi; Otake, Tsuguo

    2008-01-01

    A high lateral resolution secondary ion mass spectrometer (NanoSIMS NS50 ion microprobe) has been used to measure 87 Sr/ 86 Sr ratios in natural CaCO 3 samples. A ∼2 nA O - primary beam was used to sputter a 5-7-μm diameter crater on the sample surface and secondary positive ions were extracted for mass analysis using an accelerating voltage of 8 kV and a Mattauch-Herzog geometry. The multi-collector system was adjusted to detect 43 Ca + (by a detector EM2), 80 Ca 2 + (EM3), 86 Sr + (EM4), and 87 Sr + (EM4b) ions at the same time. Then the magnetic field was scanned for the EM4 to detect 85 Rb + , 86 Sr + and 87 Sr + , while the EM4b can measure 86 Sr + , 87 Sr + and 88 Sr + , respectively. A mass resolution of 3600 at 10% peak height was attained with a flat peak top, while the sensitivity of Sr was about 10 cps/nA/ppm. An aragonite sample (coral skeleton standard; JCp-1) was used as a reference for Sr isotope ratio calibration. Repeated analyses of the JCp-1 show that the 87 Sr/ 86 Sr ratio agrees well with the seawater signature within a precision of 0.3 per mille at 2σ, after the series of corrections such as the Ca dimer, 87 Rb, and a mass bias estimated by the 88 Sr/ 86 Sr ratio. The method was applied to an otolith (ear-stone) from ayu (Plecoglossus altivelis altivelis) collected from the Yodo river, Japan. Although experimental errors are relatively large, up to 3 per mille at 2σ, the ratios of the core region are higher than the seawater signature while more distal values agree well with seawater. The very outermost part again shows the relatively higher 87 Sr/ 86 Sr ratios. The spatial variation of 87 Sr/ 86 Sr ratios was consistent with amphidromous migration of the fish, namely, born in the lake and grown in the coastal sea and finally collected in a river

  16. Geographical traceability based on 87Sr/86Sr indicator: a first approach for PDO Lambrusco wines from Modena.

    Science.gov (United States)

    Durante, Caterina; Baschieri, Carlo; Bertacchini, Lucia; Cocchi, Marina; Sighinolfi, Simona; Silvestri, Michele; Marchetti, Andrea

    2013-12-01

    The main goal of this study was to evaluate (87)Sr/(86)Sr ratio in different matrices, namely soils, branches, and grape juices, of an oenological food chain in order to develop a robust analytical strategy able to link the investigated food to its territory of origin. The (87)Sr/(86)Sr has been used as traceability marker and several aspects, affected its variability, i.e. geological features of the investigated area, the bio-available fraction of elements in the soils and the up-take of the plant, have been taken into account. Optimisation of an analytical procedure for the separation of Sr from its interferences and investigation of the analytical performances in terms of precision of used methodology have been carried out as well. This work highlighted a good match between the isotopic values monitored in the bio-available fraction of soils and their respective grape juices for almost all the investigated areas. The correlation with food satisfyingly improves when isotopic relative abundance values of branches vine are considered. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Extraction chromatographic separation of Sr, Pu and Am in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Sidhu, Rajdeep

    2004-04-01

    An accurate determination of radionuclides from various sources in the environment is essential for assessment of the potential hazards and suitable countermeasures both in case of an authorised release, accidents and routine surveillance. Due to the short range of alpha and beta radiation, the accurate determination of pure alpha and beta emitters must always include radiochemical separations to separate the analytes from the matrix and from other interfering stable and radioactive nuclides. Hence, the procedures used for their determination are usually tedious and involve several preconcentration and separation steps. This work deals with the determination of {sup 90}Sr, {sup 241}Am, {sup 238}Pu, {sup 239,240}Pu and {sup 244}Cm, whic some of the most important artificial radionuclides. Due to either absence or low yield of gamma radiation, a secure determination of low concentrations of all these nuclides requires a dedicated chemistry. Selective extraction chromatographic resins (TRU- and Sr-Resin) have been utilised to develop new procedures for the analyses of Pu, Am and Cm isotopes in seawater and both these and {sup 90}Sr in soil, sediment, urine and low-level liquid radioactive effluents. The proposed method for the analyses of Pu and Am in seawater offers a quick and secure mode for the determination of these radionuclides in marine waters. Combined pre-concentration of actinides and strontium (oxalate or phosphate precipitation) followed by dual column separation on TRU- and Sr-Resin significantly reduces the through put time and costs compared to traditional ion exchange and precipitation methods. The greatest gain in productivity and environmental friendliness is achieved in Sr separations using Sr-Resin instead of precipitations involving fuming nitric acid and oxalate, hydroxide, chromate and carbonate precipitations. (author)

  18. Strontium and argon isotopes in naturally weathered biotites, muscovites and feldspars

    International Nuclear Information System (INIS)

    Clauer, N.

    1981-01-01

    A Rb-Sr and K-Ar isotopical study on progressively weathered biotites, muscovites and feldspars from plutonic and eruptive rocks shows that their continental weathering is a complex phenomenon controlled by environmental conditions. During weathering of biotites, the K-Ar couple often mimics the Rb-Sr couple. The radiogenic Sr and Ar isotopes are systematically leached out, but the behaviour of the elemental Rb, K, Sr and Ar depends upon the environment. In contrast, the Sr and Ar balances of muscovites are maintained, even during very intensive weathering. In mixtures of feldspars, the common Sr seems to be leached out preferentially to the radiogenic isotope, while the K-Ar balance is maintained. (Auth.)

  19. Pb-Sr-Nd-O isotopic characterization of Mesozoic rocks throughout the northern end of the Peninsular Ranges batholith: Isotopic evidence for the magmatic evolution of oceanic arc–continental margin accretion during the Late Cretaceous of southern California

    Science.gov (United States)

    Kistler, Ronald W.; Wooden, Joseph L.; Premo, Wayne R.; Morton, Douglas M.

    2014-01-01

    Within the duration of the U.S. Geological Survey (USGS)–based Southern California Areal Mapping Project (SCAMP), many samples from the northern Peninsular Ranges batholith were studied for their whole-rock radioisotopic systematics (rubidium-strontium [Rb-Sr], uranium-thorium-lead [U-Th-Pb], and samarium-neodymium [Sm-Nd]), as well as oxygen (O), a stable isotope. The results of three main studies are presented separately, but here we combine them (>400 analyses) to produce a very complete Pb-Sr-Nd-O isotopic profile of an arc-continent collisional zone—perhaps the most complete in the world. In addition, because many of these samples have U-Pb zircon as well as argon mineral age determinations, we have good control of the timing for Pb-Sr-Nd-O isotopic variations.The ages and isotopic variations help to delineate at least four zones across the batholith from west to east—an older western zone (126–108 Ma), a transitional zone (111–93 Ma), an eastern zone (94–91 Ma), and a much younger allochthonous thrust sheet (ca. 84 Ma), which is the upper plate of the Eastern Peninsular Ranges mylonite zone. Average initial 87Sr/86 Sr (Sri), initial 206Pb/204Pb (206 Pbi), initial 208Pb/204Pb (average 208Pbi), initial epsilon Nd (average εNdi), and δ18O signatures range from 0.704, 18.787, 38.445, +3.1, and 4.0‰–9.0‰, respectively, in the westernmost zone, to 0.7071, 19.199, 38.777, −5, and 9‰–12‰, respectively, in the easternmost zone. The older western zone is therefore the more chemically and isotopically juvenile, characterized mostly by values that are slightly displaced from a mantle array at ca. 115 Ma, and similar to some modern island-arc signatures. In contrast, the isotopic signatures in the eastern zones indicate significant amounts of crustal involvement in the magmatic plumbing of those plutons. These isotopic signatures confirm previously published results that interpreted the Peninsular Ranges batholith as a progressively

  20. Development of techniques for rapid analysis of 90Sr breakthrough and 90Y activity from a 90Sr-90Y generator

    International Nuclear Information System (INIS)

    Chism, S.E.; Goodwin, D.A.; Meares, C.F.

    1986-01-01

    Recently there has been interest in labelling monoclonal antibodies with therapeutic amounts of a pure beta emitting isotope. 90 Y offers many desirable features and may be conveniently and economically obtained from a 90 Sr- 90 Y generator. A potential hazard with this system is breakthrough of the parent 90 Sr which has a half life of 28 years and is an extremely toxic bone seeking isotope. Therefore it is essential that the daughter be completely separated from its parent. We have devised two simple techniques which allow us to monitor rapidly the amount of 90 Sr breakthrough and quantitate the 90 Y activity over a 5 log range. (author)

  1. Nd-Sr isotopic compositions of dissolved and particulate material transported by the Parana and Uruguay rivers during high (december 1993) and low (september 1994) water periods

    International Nuclear Information System (INIS)

    Henry, F.; Thouron, D.; Garcon, V.; Henry, F.; Probst, J.L.

    1996-01-01

    Our motivation is to better constrain the neodymium and strontium isotopic signatures of the closest continental riverine source (Parana and Uruguay rivers) to the Brazil/Malvinas Confluence zone in the Southwest Atlantic Ocean. We thus present new isotopic data on the Nd and Sr of the dissolved and suspended loads of the Parana and Uruguay rivers for two water periods forming the Rio de la Plata whose drainage basin is the second largest one in South America. The Parana dissolved material shows less radiogenic (ε Nd (0) ranging between -12.1 and -8.2) than the Uruguay one with a mean ε Nd (0) value of -6.3 ± 0.3. Suspended particulates display the same isotopic trend (mean ε Nd (0) value of -10.3 and -6.0 for the Parana and Uruguay rivers, respectively). Dissolved load 87 Sr/ 86 Sr in the Parana (0.7123) is found to be more radiogenic than the Uruguay one (0.7097); the suspended load follows the same trend with 87 Sr/ 86 Sr ratios of 0.7247 and 0.7115 in the Parana and Uruguay rivers, respectively. The relatively radiogenic Nd and non radiogenic Sr of the Uruguay River as compared to the Parana River could be attributed to a predominance of tholeiitic basalts in the drainage basin. A revisited estimation of the fluxes of Nd considering all South American rivers delivering into the western South and Tropical Atlantic Ocean yields a Nd particulate flux to estuarine water two orders of magnitude higher than the Nd dissolved flux. Considering the net dissolved and suspended fluxes of Nd reaching the Rio de la Plata, we have calculated a resulting ε Nd (0) equal to -10.2. The computation of ε Nd (0) of the Rio de la Plata outflow waters gives a value of -8.3, taking into account various removal processes within the estuary. (authors)

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

    Science.gov (United States)

    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.

  3. Assessing Covariation of Holocene Monsoon Intensity and Local Moisture Conditions in Eastern and Southwestern Amazon Basin Using Speleothem δ18O and 87Sr/86Sr Values

    Science.gov (United States)

    Ward, B. M.; Wong, C. I.; Novello, V. F.; Silva, L.; McGee, D.; Cheng, H.; Wang, X.; Edwards, R. L.; Cruz, F. W., Sr.; Santos, R. V.

    2017-12-01

    δ18O records from South America offer insight into past variability of the South American Monsoon System (SAMS). Potential, however, for understanding local moisture conditions is limited as precipitation δ18O is strongly influenced by regional climate dynamics. Here we create Holocene speleothem 87Sr/86Sr records at 200-yr resolution using TIMS methods in the Center for Isotope Geochemistry at Boston College to complement existing Holocene δ18O speleothem records and investigate local moisture conditions above caves located in the eastern Amazon Basin (PAR - 4°S, 55°W) and southwestern Brazil (JAR - 21°S, 56°W). Speleothem 87Sr/86Sr variability is interpreted to reflect differences in the extent of water-rock interaction due to differences in infiltration rates under wet and dry conditions. Drier conditions promote longer residence time, enhanced water-rock interaction, and greater evolution of dripwater 87Sr/86Sr values from an initial isotopic signature acquired from the soil to the signature of the cave host rock. PAR speleothem 87Sr/86Sr values range from 0.71024 to 0.71067 and are bracketed by soil (0.71710 to 0.70956) and bedrock (0.70852 to 0.70899) values. JAR speleothem 87Sr/86Sr values range from 0.71216 to 0.71539 and are greater than bedrock values (0.70825 to 0.71219), although some speleothem values exceed the single analysis conducted of the soil isotopic composition (0.71473). JAR speleothem 87Sr/86Sr values increase from the early to mid Holocene, consistent with increase in local moisture availability associated with intensification of the SAMS suggested by decreasing δ18O values in many records from the region. Speleothem 87Sr/86Sr values at JAR decrease from the mid to late Holocene, consistent with an increase in δ18O values at PAR that suggest a decline in monsoon intensity. 87Sr/86Sr variability at JAR, however, is positively correlated with the δ18O record. Preliminary 87Sr/86Sr results from PAR are only broadly consistent with

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

    Energy Technology Data Exchange (ETDEWEB)

    Moynier, Frederic; Podosek, Frank A. [Department of Earth and Planetary Science and McDonnell Center for Space Sciences, Washington University, St. Louis, MO 63130 (United States); Day, James M. D. [Geosciences Research Division, Scripps Institution of Oceanography, La Jolla, CA 92093-0244 (United States); Okui, Wataru; Yokoyama, Tetsuya [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Bouvier, Audrey [Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455-0231 (United States); Walker, Richard J., E-mail: moynier@levee.wustl.edu, E-mail: fap@levee.wustl.edu, E-mail: jmdday@ucsd.edu, E-mail: rjwalker@umd.edu, E-mail: okui.w.aa@m.titech.ac.jp, E-mail: tetsuya.yoko@geo.titech.ac.jp, E-mail: abouvier@umn.edu [Department of Geology, University of Maryland, College Park, MD 20742 (United States)

    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.

  5. Strontium isotope fractionation in soils and pedogenic processes

    Energy Technology Data Exchange (ETDEWEB)

    Shalev, Netta [Institute of Earth Sciences, The Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Geological Survey of Israel, 30 Malkhe Israel Street, 95501 Jerusalem (Israel); Lazar, Boaz [Institute of Earth Sciences, The Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Halicz, Ludwik; Stein, Mordechai; Gavrieli, Ittai; Sandler, Amir; Segal, Irena [Geological Survey of Israel, 30 Malkhe Israel Street, 95501 Jerusalem (Israel)

    2013-07-01

    The stable isotope composition of strontium (the ratio {sup 88}Sr/{sup 86}Sr expressed as δ{sup 88/86}Sr) showed significant fractionation in mountain soils of the Judea Highland. In order to understand this phenomenon, we studied the elemental composition and the stable and radiogenic Sr isotopic composition in soil transects conducted from semi-arid (desert fringe) to wetter (Mediterranean) climate zones. These transects were selected because the degree of soil leaching depends on the amount of precipitation and the permeability of the underlying bedrock. These soils are the pedogenic products of leaching of the accumulated desert dust and the underlying carbonate bed-rocks resulting in, among others, enrichment of the residual soils in Al-clays. A clear negative correlation was found between the δ{sup 88/86}Sr and Al{sub 2}O{sub 3} (Al-clay content) values of the soils, the high δ{sup 88/86}Sr-low Al{sub 2}O{sub 3} being the dust end-member. This preliminary study demonstrates the feasibility of using stable {sup 88}Sr-{sup 86}Sr isotopes as tracers of terrestrial weathering processes. (authors)

  6. Trace-element and Sr, Nd, Pb, and O isotopic composition of Pliocene and Quaternary alkali basalts of the Patagonian Plateau lavas of southernmost South America

    Science.gov (United States)

    Stern, C.R.; Frey, F.A.; Futa, K.; Zartman, R.E.; Peng, Z.; Kurtis, Kyser T.

    1990-01-01

    The Pliocene and Quaternary Patagonian alkali basalts of southernmost South America can be divided into two groups. The "cratonic" basalts erupted in areas of Cenozoic plateau volcanism and continental sedimentation and show considerable variation in 87Sr/86Sr (0.70316 to 0.70512), 143Nd/144Nd (e{open}Nd) and 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios (18.26 to 19.38, 15.53 to 15.68, and 38.30 to 39.23, respectively). These isotopic values are within the range of oceanic island basalts, as are the Ba/La, Ba/Nb, La/Nb, K/Rb, and Cs/Rb ratios of the "cratonic" basalts. In contrast, the "transitional" basalts, erupted along the western edge of the outcrop belt of the Pliocene and Quaternary plateau lavas in areas that were the locus of earlier Cenozoic Andean orogenic arc colcanism, have a much more restricted range of isotopic composition which can be approximated by 87Sr/86Sr=0.7039??0.0004, e{open}Nd, 206Pb/204Pb=18.60??0.08, 207Pb/204Pb=15.60??0.01, and 208Pb/204Pb=38.50??0.10. These isotopic values are similar to those of Andean orogenic are basalts and, compared to the "cratonic" basalts, are displaced to higher 87Sr/86Sr at a given 143Nd/144Nd and to higher 207Pb/204Pb at a given 208Pb/204Pb. The "transitional" basalts also have Ba/La, Ba/Nb, La/Nb, and Cs/Rb ratios higher than the "cratonic" and oceanic island basalts, although not as high as Andean orogenic are basalts. In contrast to the radiogenic isotopes, ??18O values for both groups of the Patagonian alkali basalts are indistinguishable and are more restricted than the range reported for Andean orogenic are basalts. Whole rock ??18O values calculated from mineral separates for both groups range from 5.3 to 6.5, while measured whole rock ??18O values range from 5.1 to 7.8. The trace element and isotopic data suggest that decreasing degrees of partial melting in association with lessened significance of subducted slabderived components are fundamental factors in the west to east transition from arc

  7. Applicability of 87Sr/86Sr in examining return flow of irrigation water in highly agricultural watersheds in Japan

    Science.gov (United States)

    Yoshida, T.; Nakano, T.; Shin, K. C.; Tsuchihara, T.; Miyazu, S.; Kubota, T.

    2017-12-01

    Water flows in watersheds containing extensive areas of irrigated paddies are complex because of the substantial volumes involved and the repeated cycles of water diversion from, and return to, streams. For better management of low-flow conditions, numerous studies have attempted to quantify the return flow using the stable isotopes of water; however, the temporal variation in these isotopic compositions due to fractionation during evaporation from water surfaces hinders their application to watersheds with extensive irrigated paddies. In this study, we tested the applicability of the strontium isotopes (87Sr/86Sr, hereafter Sr ratio) for studying hydrological processes in a typical agricultural watershed located on the alluvial fan of the Kinu River, namely the Gogyo River, in central Japan. The Sr ratio of water changes only because of interactions with the porous media it flows through, or because of mixing with water that has different Sr ratios. We sampled water both at a single rice paddy, and on the watershed scale in the irrigated and non-irrigated periods. The soil water under the paddy decreased as sampling depth increased, and the soil water at a depth of 1.5 m showed a similar Sr ratio to the spring. The water sampled in the drainage channel with a concrete lined bottom showed a similar Sr ratio to the irrigation water, whereas that with a soil bottom was plotted between the plots of the irrigation water and shallow aquifer. These results suggest the Sr ratio decreases as it mixes with the soil water through percolation; whereas the Sr ratio will be less likely to change when water drains from paddies via surface pathways. The streamflow samples were plotted linearly on the Sr ratio and 1/Sr plot, indicating that the streamflow was composed of two end-members; the irrigation water and the shallow aquifer. The continuous decline in the Sr ratio along the stream suggests an exfiltration of water from the shallow aquifers. The stream water during the non

  8. Strontium and neodymium isotopic compositions in sediments from Godavari, Krishna and Pennar rivers

    International Nuclear Information System (INIS)

    Masood Ahmad, S.; Padmakumari, V.M.; Anil Babu, G.

    2009-01-01

    We report here strontium (Sr) and neodymium (Nd) isotopic compositions in bed sediments from the Godavari, Krishna and Pennar rivers, draining into the Bay of Bengal. The isotopic compositions of these sediments range from 0.7190 to 0.7610 for 87 Sr/ 86 Sr and -12.04 to -23.68 for ε Nd . This wide range in Sr and Nd isotopes is derived from variable proportions of sediments from different rock types in their drainage basins. All the three rivers have their characteristic isotopic signatures. The results display highest 87 Sr/ 86 Sr (0.7610) and most negative ε Nd values (-23.68) for the sediments of Pennar river. This is attributed to the chemical weathering of gneisses and granites in its drainage basin. The 87 Sr/ 86 Sr and ε Nd values for the Godavari river sediments range from 0.7196 to 0.7210 and -15.31 to -18.22 respectively. 87 Sr/ 86 Sr and ε Nd values in Krishna river sediments lie from 0.7217 to 0.7301 and -12.04 to -12.78 respectively. Our results show that the sedimentary load from the Godavari and Krishna rivers is primarily derived from the older rocks in their drainage basins. It is possible that the sediments transported through peninsular Indian rivers predominantly control Sr and Nd isotope sedimentary budget in the western Bay of Bengal. (author)

  9. The Late Devonian Frasnian-Famennian (F/F) biotic crisis: Insights from δ13C carb, δ13C org and 87Sr / 86Sr isotopic systematics

    Science.gov (United States)

    Chen, Daizhao; Qing, Hairuo; Li, Renwei

    2005-06-01

    A severe biotic crisis occurred during the Late Devonian Frasnian-Famennian (F/F) transition (± 367 Myr). Here we present δ13C carb, δ13C org and 87Sr / 86Sr isotopic systematics, from identical samples of two sections across F/F boundary in South China, which directly demonstrate large and frequent climatic fluctuations (˜200 kyr) from warming to cooling during the F/F transition. These climate fluctuations are interpreted to have been induced initially by increased volcanic outgassing, and subsequent enhanced chemical weathering linked to the rapid expansion of vascular plants on land, which would have increased riverine delivery to oceans and primary bioproductivity, and subsequent burial of organic matter, thereby resulting in climate cooling. Such large and frequent climatic fluctuations, together with volcanic-induced increases in nutrient (e.g., biolimiting Fe), toxin (sulfide) and anoxic water supply, and subsequent enhanced riverine fluxes and microbial bloom, were likely responsible for the stepwise faunal demise of F/F biotic crisis.

  10. Sr isotope stratigraphy of some Rupelian carbonated laminites from the Limagne Basin: influence of seawater in the rift of the French Massif central?

    International Nuclear Information System (INIS)

    Briot, D.; Poidevin, J.L.

    1998-01-01

    87 Sr/ 86 Sr ratios of biogenic and abiotic calcites Upper Rupelian sediments in the Limagne rift (French Massif Central) define a smooth and regular negative correlation with time interrupted by repetitive sharp peaks; the progressive drop in isotopic ratio can be explained by the geological evolution of the river basin through time. Negative peaks are explained by synsedimentary volcanism, repeated marine incursions, or leaching of ancient evaporites. Comparison with available paleontologic data does not favour the volcanic explanation, but rather the influence of Rupelian marine waters. (authors)

  11. Ion microprobe Sr isotope analysis of carbonates with about 5 {mu}m spatial resolution: An example from an ayu otolith

    Energy Technology Data Exchange (ETDEWEB)

    Sano, Yuji [Center for Advanced Marine Research, Ocean Research Institute, University of Tokyo, Nakano-ku, Tokyo 164-8639 (Japan)], E-mail: ysano@ori.u-tokyo.ac.jp; Shirai, Kotaro [International Coastal Research Center, Ocean Research Institute, University of Tokyo, Otsuchi, Iwate 028-1102 (Japan); Takahata, Naoto; Amakawa, Hiroshi [Center for Advanced Marine Research, Ocean Research Institute, University of Tokyo, Nakano-ku, Tokyo 164-8639 (Japan); Otake, Tsuguo [International Coastal Research Center, Ocean Research Institute, University of Tokyo, Otsuchi, Iwate 028-1102 (Japan)

    2008-08-15

    A high lateral resolution secondary ion mass spectrometer (NanoSIMS NS50 ion microprobe) has been used to measure {sup 87}Sr/{sup 86}Sr ratios in natural CaCO{sub 3} samples. A {approx}2 nA O{sup -} primary beam was used to sputter a 5-7-{mu}m diameter crater on the sample surface and secondary positive ions were extracted for mass analysis using an accelerating voltage of 8 kV and a Mattauch-Herzog geometry. The multi-collector system was adjusted to detect {sup 43}Ca{sup +} (by a detector EM2), {sup 80}Ca{sub 2}{sup +} (EM3), {sup 86}Sr{sup +} (EM4), and {sup 87}Sr{sup +} (EM4b) ions at the same time. Then the magnetic field was scanned for the EM4 to detect {sup 85}Rb{sup +}, {sup 86}Sr{sup +} and {sup 87}Sr{sup +}, while the EM4b can measure {sup 86}Sr{sup +}, {sup 87}Sr{sup +} and {sup 88}Sr{sup +}, respectively. A mass resolution of 3600 at 10% peak height was attained with a flat peak top, while the sensitivity of Sr was about 10 cps/nA/ppm. An aragonite sample (coral skeleton standard; JCp-1) was used as a reference for Sr isotope ratio calibration. Repeated analyses of the JCp-1 show that the {sup 87}Sr/{sup 86}Sr ratio agrees well with the seawater signature within a precision of 0.3 per mille at 2{sigma}, after the series of corrections such as the Ca dimer, {sup 87}Rb, and a mass bias estimated by the {sup 88}Sr/{sup 86}Sr ratio. The method was applied to an otolith (ear-stone) from ayu (Plecoglossus altivelis altivelis) collected from the Yodo river, Japan. Although experimental errors are relatively large, up to 3 per mille at 2{sigma}, the ratios of the core region are higher than the seawater signature while more distal values agree well with seawater. The very outermost part again shows the relatively higher {sup 87}Sr/{sup 86}Sr ratios. The spatial variation of {sup 87}Sr/{sup 86}Sr ratios was consistent with amphidromous migration of the fish, namely, born in the lake and grown in the coastal sea and finally collected in a river.

  12. μSR spectroscopy on free radicals: a complement to ESR spectroscopy

    International Nuclear Information System (INIS)

    Cox, S.F.J.; Symons, M.C.R.

    1986-12-01

    The paper on ''μSR spectroscopy on free radicals'' was presented to the conference on ''Muon spin, rotation, relaxation and resonance'' Uppsala, 1986. The spectroscopic techniques for both ESR and μSR are described, along with the interpretation of the spectra, hyperfine coupling constants and radical structure. A comparison of ESR and μSR data is carried out with respect: to 1) isotope effects in organic radicals, 2) isotope effects in solids, -the isotropic muonium defect centres, and 3) the muonium defect centres in semiconductors. Radical categories examined using ESR and μSR are discussed, including new species, formation mechanisms, and ionic species. (U.K.)

  13. Grain-scale Sr isotope heterogeneity in amphibolite (retrograded UHP eclogite, Dabie terrane): Implications for the origin and flow behavior of retrograde fluids during slab exhumation

    Science.gov (United States)

    Guo, Shun; Yang, Yueheng; Chen, Yi; Su, Bin; Gao, Yijie; Zhang, Lingmin; Liu, Jingbo; Mao, Qian

    2016-12-01

    To constrain the origin and flow behavior of amphibolite-facies retrograde fluids during slab exhumation, we investigate the textures, trace element contents, and in situ strontium (Sr) isotopic compositions (using LA-MC-ICP-MS) of multiple types of epidote and apatite in the UHP eclogite and amphibolites from the Hualiangting area (Dabie terrane, China). The UHP epidote porphyroblasts in the eclogite (Ep-E), which formed at 28-30 kbar and 660-720 °C, contain high amounts of Sr, Pb, Th, Ba, and light rare earth elements (LREEs) and have a narrow range of initial 87Sr/86Sr ratios (0.70431 ± 0.00012 to 0.70454 ± 0.00010). Two types of amphibolite-facies epidote were recognized in the amphibolites. The first type of epidote (Ep-AI) developed in all the amphibolites and has slightly lower trace element contents than Ep-E. The Ep-AI has a same initial 87Sr/86Sr ratio range as the Ep-E and represents the primary amphibolite-facies retrograde product that is associated with an internally buffered fluid at 8.0-10.3 kbar and 646-674 °C. The other type of epidote (Ep-AII) occurs as irregular fragments, veins/veinlets, or reaction rims on the Ep-AI in certain amphibolites. Elemental X-ray maps reveal the presence of Ep-AI relics in the Ep-AII domains (appearing as a patchy texture), which indicates that Ep-AII most likely formed by the partial replacement of the Ep-AI in the presence of an infiltrating fluid. The distinctly lower trace element contents of Ep-AII are ascribed to element scavenging by a mechanism of dissolution-transport-precipitation during replacement. The Ep-AII in an individual amphibolite exhibits large intra- and inter-grain variations in the initial 87Sr/86Sr ratios (0.70493 ± 0.00030 to 0.70907 ± 0.00022), which are between those of the Ep-AI and granitic gneisses (wall rock of the amphibolites, 0.7097-0.7108). These results verify that the infiltrating fluid was externally derived from granitic gneisses. The matrix apatite in the amphibolites has

  14. Large-scale purification of {sup 90}Sr from nuclear waste materials for production of {sup 90}Y, a therapeutic medical radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Wester, D.W.; Steele, R.T.; Rinehart, D.E.; DesChane, J.R.; Carson, K.J.; Rapko, B.M.; Tenforde, T.S. E-mail: tenforde@ncrp.com

    2003-07-01

    A major limitation on the supply of the short-lived medical isotope {sup 90}Y (t{sub 1/2}=64 h) is the available quantity of highly purified {sup 90}Sr generator material. A radiochemical production campaign was therefore undertaken to purify 1500 Ci of {sup 90}Sr that had been isolated from fission waste materials. A series of alkaline precipitation steps removed all detectable traces of {sup 137}Cs, alpha emitters, and uranium and transuranic elements. Technical obstacles such as the buildup of gas pressure generated upon mixing large quantities of acid with solid {sup 90}Sr carbonate were overcome through safety features incorporated into the custom-built equipment used for {sup 90}Sr purification. Methods are described for analyzing the chemical and radiochemical purity of the final product and for accurately determining by gravimetry the quantities of {sup 90}Sr immobilized on stainless steel filters for future use.

  15. Magnesium stable isotope ecology using mammal tooth enamel

    Science.gov (United States)

    Martin, Jeremy E.; Vance, Derek; Balter, Vincent

    2015-01-01

    Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

  16. 878787Sr/868686Sr anomalies in Late Cretaceous-Early Tertiary ...

    Indian Academy of Sciences (India)

    paper documents the occurrences of two positive. 87. Sr/. 86 ... Analysis of trace elemental and stable isotopic profiles, sedimentation history ... et al (1980) and report of similar anomalies from ...... through the financial assistance of Alexander von. Humboldt ... and extinction events in earth history; Science 240. 996–1002.

  17. Age and origin of anorthosites, charnockites, and granulites in the Central Virginia Blue Ridge: Nd and Sr isotopic evidence

    Science.gov (United States)

    Pettingill, H.S.; Sinha, A.K.; Tatsumoto, M.

    1984-01-01

    Rb-Sr isotopic data for anorthosites, charnockites, ferrodioritic to quartz monzonitic plutons, and high-grade gneisses of the Blue Ridge of central Virginia show evidence of post-emplacement metamorphism, but in some cases retain Grenville ages. The Pedlar River Charnockite Suite yields an isochron age of 1021 +/-36 Ma, (initial 87Sr/86Sr ratio of 0.7047 +/-6), which agrees with published U-Pb zircon ages. Five samples of that unit which contain Paleozoic mylonitic fabrics define a regression line of 683 Ma, interpreted as a mixing line with no age significance. Samples of the Roseland Anorthosite Complex show excessive scatter on a Rb-Sr evolution diagram probably due to Paleozoic (475 m.y.) metamorphism. Data from the ferrodioritic to quartz monzonitic plutons of the area yield an age of 1009 +/-26 Ma (inital ratio=0.7058 +/-4), which is in the range of the U-Pb zircon ages of 1000-1100 Ma. The Stage Road Layered Gneiss yields an age of 1147 +/-34 Ma (initial ratio of 0.7047 +/- 5). Sm-Nd data for the Pedlar River Charnockite Suite reflect a pre-Grenville age of 1489 +/-118 Ma (e{open}Nd=+6.7 +/-1.2). Data for the Roseland Anorthosite Complex and the ferrodioritic to quartz monzonitic plutons yield Grenville isochron ages of 1045 +/44 Ma (e{open}Nd=+1.0 +/-0.3) and 1027 +/-101 Ma (e{open}Nd=+1.4 +/-1.0), respectively. Two Roseland Anorthosite samples plot far above the isochron, demonstrating the effects of post-emplacement disturbance of Sm-Nd systematics, while mylonitized Pedlar River Charnockite Suite samples show no evidence of Sm-Nd redistribution. The disparity of the Sm-Nd age and other isotopic ages for the Pedlar River Charnockite Suite probably reflects a Sm-Nd "source" age, suggesting the presence of an older crust within this portion of the ca. 1 Ga old basement. ?? 1984 Springer-Verlag.

  18. Novel approaches for 90Sr analyses in contaminated environmental samples

    International Nuclear Information System (INIS)

    Kavasi, N.; Sahoot, S.K.; Area, H.; Aono, T.

    2016-01-01

    Radioactive strontium isotopes are generated with high cumulative fission yield (5-6 %) during thermal neutron fission in a nuclear reactor. The physical half-life of 89 Sr (50.52 d) is short but that of 90 Sr (28.8 y) is long enough to generate radioecological repercussions. 90 Sr has a long-lasting biological half-life (∼18 y) in the human body, due to its chemical similarity to calcium the importance of 90 Sr analysis is emphasized in case of a nuclear disaster. The world-wide spread of 90 Sr, as a background, is derived from the global atmospheric fallout contributed by large-scale atmospheric nuclear weapons tests conducted from 1945. In case of local contamination, nuclear accidents are not the only source of 90 Sr isotope, misconducted underground nuclear weapon tests; improper handling of by-products of nuclear weapon production or normal operation of nuclear facilities (e.g. reprocessing plants) can be taken into account

  19. Preliminary economic feasibility study of MIP (Medical Isotopes Producer)

    International Nuclear Information System (INIS)

    Mon, G. H.; O, S. Y.

    2004-01-01

    Preliminary economic feasibility study of MIP (Medical Isotopes Producer), which is used liquid nuclear fuel to produce medical isotopes of Mo-99 and Sr-89, was performed. To do this, this study was estimated the IRR(Internal Rate of Return) and PBP(Pay-back Period) about optimistic and pessimistic cases for market penetration of Asia and U.S.A. isotope markets. And sensitivity analysis is also performed about capital cost and price of Mo-99 and Sr-89. According to the results, IRR was between 14.9% and 24.3%, and PBP was between 4.8 years and 7.8 years. These suggest that MIP has economic merits. MIP can produce other medical isotopes such as Sr-90, I-131, Xe-133, Cs-137. So, it is necessary to do cost-benefit analysis considering production of these other isotopes

  20. The Strontium Isotope Record of Zavkhan Terrane Carbonates: Strontium Isotope Stability Through the Ediacaran-Cambrian Transition

    OpenAIRE

    Petach, Tanya N.

    2015-01-01

    First order trends in the strontium isotopic (87Sr/86Sr) composition of seawater are controlled by radiogenic inputs from the continent and non-radiogenic inputs from exchange at mid-ocean ridges. Carbonates precipitated in seawater preserve trace amounts of strontium that record this isotope ratio and therefore record the relative importance of mid-ocean ridge and weathering chemical inputs to sea water composition. It has been proposed that environmental changes during the Ediacaran-Cambria...

  1. Sr-Nd-Pb isotopic constraints on the nature of the mantle sources involved in the genesis of the high-Ti tholeiites from northern Paraná Continental Flood Basalts (Brazil)

    Science.gov (United States)

    Rocha-Júnior, Eduardo R. V.; Marques, Leila S.; Babinski, Marly; Nardy, Antônio J. R.; Figueiredo, Ana M. G.; Machado, Fábio B.

    2013-10-01

    There has been little research on geochemistry and isotopic compositions in tholeiites of the Northern region from the Paraná Continental Flood Basalts (PCFB), one of the largest continental provinces of the world. In order to examine the mantle sources involved in the high-Ti (Pitanga and Paranapanema) basalt genesis, we studied Sr, Nd, and Pb isotopic systematics, and major, minor and incompatible trace element abundances. The REE patterns of the investigated samples (Pitanga and Paranapanema magma type) are similar (parallel to) to those of Island Arc Basalts' REE patterns. The high-Ti basalts investigated in this study have initial (133 Ma) 87Sr/86Sr ratios of 0.70538-0.70642, 143Nd/144Nd of 0.51233-0.51218, 206Pb/204Pb of 17.74-18.25, 207Pb/204Pb of 15.51-15.57, and 208Pb/204Pb of 38.18-38.45. These isotopic compositions do not display any correlation with Nb/Th, Nb/La or P2O5/K2O ratios, which also reflect that these rocks were not significantly affected by low-pressure crustal contamination. The incompatible trace element ratios and Sr-Nd-Pb isotopic compositions of the PCFB tholeiites are different to those found in Tristan da Cunha ocean island rocks, showing that this plume did not play a substantial role in the PCFB genesis. This interpretation is corroborated by previously published osmium isotopic data (initial γOs values range from +1.0 to +2.0 for high-Ti basalts), which also preclude basalt generation by melting of ancient subcontinental lithospheric mantle. The geochemical composition of the northern PCFB may be explained through the involvement of fluids and/or small volume melts related to metasomatic processes. In this context, we propose that the source of these magmas is a mixture of sublithospheric peridotite veined and/or interlayered with mafic components (e.g., pyroxenites or eclogites). The sublithospheric mantle (dominating the osmium isotopic compositions) was very probably enriched by fluids and/or magmas related to the

  2. Pb sbnd Sr sbnd Nd isotopic data of Indian Ocean ridges: new evidence of large-scale mapping of mantle heterogeneities

    Science.gov (United States)

    Hamelin, Bruno; Dupré, Bernard; Allègre, Claude J.

    1986-01-01

    A Pb sbnd Sr sbnd Nd isotope study of South West and East Indian Ridges confirms that the Indian Ocean belongs to a specific regional isotopic domain, as previously suggested by the results from islands of this ocean. The isotopic domain defined by the Indian MORB is indeed different from that of the North Atlantic and East Pacific Oceans. This demonstrates that the convective circulation of the upper mantle does not allow a rapid homogenization from one region to the other. The isotopic data of the Indian ridges can be interpreted by a contamination model, in which the depleted upper mantle (identical to that under the North Atlantic) is contaminated by two different types of contaminant, one corresponding to the source of the "central Indian Ocean" islands (Amsterdam, St. Paul, Marion, Prince Edward, Réunion, Rodriguez, Mauritius), and the other to a source similar to that of Walvis or Ninety East aseismic ridges. These two contaminants would have contributed to the ridge volcanism in different proportions over time.

  3. Isotopic coherence of refractory inclusions from CV and CK meteorites: Evidence from multiple isotope systems

    Science.gov (United States)

    Shollenberger, Quinn R.; Borg, Lars E.; Render, Jan; Ebert, Samuel; Bischoff, Addi; Russell, Sara S.; Brennecka, Gregory A.

    2018-05-01

    Calcium-aluminum-rich inclusions (CAIs) are the oldest dated materials in the Solar System and numerous previous studies have revealed nucleosynthetic anomalies relative to terrestrial rock standards in many isotopic systems. However, most of the isotopic data from CAIs has been limited to the Allende meteorite and a handful of other CV3 chondrites. To better constrain the isotopic composition of the CAI-forming region, we report the first Sr, Mo, Ba, Nd, and Sm isotopic compositions of two CAIs hosted in the CK3 desert meteorites NWA 4964 and NWA 6254 along with two CAIs from the CV3 desert meteorites NWA 6619 and NWA 6991. After consideration of neutron capture processes and the effects of hot-desert weathering, the Sr, Mo, Ba, Nd, and Sm stable isotopic compositions of the samples show clearly resolvable nucleosynthetic anomalies that are in agreement with previous results from Allende and other CV meteorites. The extent of neutron capture, as manifested by shifts in the observed 149Sm-150Sm isotopic composition of the CAIs is used to estimate the neutron fluence experienced by some of these samples and ranges from 8.40 × 1013 to 2.11 × 1015 n/cm2. Overall, regardless of CAI type or host meteorite, CAIs from CV and CK chondrites have similar nucleosynthetic anomalies within analytical uncertainty. We suggest the region that CV and CK CAIs formed was largely uniform with respect to Sr, Mo, Ba, Nd, and Sm isotopes when CAIs condensed and that CAIs hosted in CV and CK meteorites are derived from the same isotopic reservoir.

  4. Isotope migration and barrier in a VLLW site

    International Nuclear Information System (INIS)

    Kang Houjun; Zhang Dong; Yang Yong; Shi Zhengkun; Li Kuanliang; Zhang Peicong

    2010-01-01

    In this work, adsorption and migration of 238 U and 90 Sr in unsaturated soil at a VLLW (very low level waste) site was investigated, in an attempt to find geochemical features of the site. Migration of the isotopes in heterosphere was studied under instantaneous and sequential conditions of the sources. The migration barrier experiment was carried out in two steps on wall rock absorption of the isotopes and addictives to improve the barrier of the wall rock to 90 Sr. The results show that the migration speed of 238 U and 90 Sr in the soil is 0.365 and 0.385 mm/a, respectively. The heterosphere effects on the isotope migration not only alleviated the mainstream contamination, but also prolonged the time of contaminated affection. And false zeolite should be used as barrier additive material for 90 Sr migration. (authors)

  5. Changing styles of crustal growth in Southern Africa: constraints from geochemical and Sr-Nd isotope studies in Archaean to Pan African terrains

    International Nuclear Information System (INIS)

    McDermott, F.; Hawkesworth, C.J.; Harris, N.B.W.

    1988-01-01

    Nd isotopic data was presented for southern Africa in support of episodic crustal growth. Over 50 percent of the continental crust there had formed before 2.5 Ga, and less than 10 percent was produced after about 1.0 Ga. The data imply a mean crustal age of about 2.4 Ga for southern Africa, and a higher rate of crustal growth than that derived from Australian shale data, particularly during the Proterozoic. Isotopic data from Damara metasediments imply that there is no need to invoke decoupling of the Rb-Sr and Sm-Nd systems in the continental crust

  6. Changing styles of crustal growth in Southern Africa: Constraints from geochemical and Sr-Nd isotope studies in Archaean to Pan African terrains

    Science.gov (United States)

    Mcdermott, F.; Hawkesworth, C. J.; Harris, N. B. W.

    1988-01-01

    Nd isotopic data was presented for southern Africa in support of episodic crustal growth. Over 50 percent of the continental crust there had formed before 2.5 Ga, and less than 10 percent was produced after about 1.0 Ga. The data imply a mean crustal age of about 2.4 Ga for southern Africa, and a higher rate of crustal growth than that derived from Australian shale data, particularly during the Proterozoic. Isotopic data from Damara metasediments imply that there is no need to invoke decoupling of the Rb-Sr and Sm-Nd systems in the continental crust.

  7. Study on Nd and Sr isotopes of Yianshanian mafic rocks in east Lanling area and their implication

    International Nuclear Information System (INIS)

    Zhang Shuming; Wu Jianhua; Zhou Weixun

    2003-01-01

    East Nanling's Yianshanian mafic magna activity can be divided into four phase. The four phase are the Middle Jurassic, the Late Jurassic, the Early Cretaceous and the Late Cretaceous. They are also four important episodes of extensional activities. The four phase mafic rock possess similar Nd-Sr isotope characteristics, high I Sr (commonly from 0.705 to 0.710) and ε Nd values change range wide (from -7.90 to 5.16). It shows crust-mantle mixed magma origin character. The mafic rock possess the character of within-plate basalts,indicated that they are formed within-plate, and showed there were post-orogenic phase at the early Yianshanian's Middle Jurassic in east Nanling area. The rocks formed pattern is mafic magma rise to the crust bottom, were contaminate by crustal materials, and formed in the setting of lithosphere extended and crust extension. East Nanling's Yianshanian magna activity is mainly magma event concern with mantle magma underplating. (authors)

  8. Rb-Sr geochronology of the rocks of the Himalayas, Eastern Nepal, (1)

    International Nuclear Information System (INIS)

    Kai, Kunio

    1981-01-01

    Rb-Sr isotopic measurements were carried out for whole rock and small sliced rock from the Himalayan gneiss which constitutes the metamorphosed basement of the Tethyan sediments. The results of the measurements on whole rock from the Barun migmatite, the Barun gneiss and the Irkhua gneiss indicate that complete Sr isotopic redistribution occurred about 520 m.y. ago. This age is interpreted as the time of the regional metamorphism. The analytical results of the small sliced slabs of the Himalayan gneiss indicate that Sr isotopic redistribution occurred among the sliced slabs 33.3 +- 13.2 m.y. ago. This age is interpreted as the time of the metamorphism in the sillimanite-amphibolite facies. The high initial 87 Sr/ 86 Sr ratio of 0.7372 +- 0.0031 from the Barun migmatite of the Himalayan gneiss suggests the Precambrian Origin of the source rocks. The analytical results on the sliced slab of the Barun migmatite indicate that the original age of the rocks is about 800 m.y. The rock is interpreted as the remobilized Precambrian crustal rock. The high initial 87 Sr/ 86 Sr ratio of the Barun gneiss and the Irkhua gneiss of the Himalayan gneiss (0.7234 +- 0.0013) indicates also the Precambrian origin of the source rocks. (author)

  9. Anglo-Saxon animal husbandry techniques revealed though isotope and chemical variations in cattle teeth

    International Nuclear Information System (INIS)

    Evans, J.A.; Tatham, S.; Chenery, S.R.; Chenery, C.A.

    2007-01-01

    The Sr concentration and isotope composition of tooth enamel from domesticated animals from two neighbouring Anglo-Saxon settlements, at Empingham (6-7th century) and Ketton (10-12th century) in Rutland, central England, are compared both with each other, and with associated human populations. Data from the Empingham II site form discrete fields in Sr concentration and isotope composition space for cattle, pig and sheep with a partial overlap of the human and pig fields. By contrast there is significant overlap in all the animal and human data fields from the Ketton site. The differences in data distribution between the two sites are attributed to animal husbandry techniques, as the surface geology of the two areas is very similar, implying geological factors are an unlikely cause of the difference. It is suggested that the grazing and feeding patterns of animals at the Empingham II site were controlled and restricted, whereas at the Ketton site the animals grazed and foraged freely over a common area. Strontium isotope variation within cattle molars from the two settlements show marked differences that reflect the nature of their feeding and rearing. The enamel from a cattle molar from the Empingham II site has a well-defined, systematic variation of Sr isotope composition with Sr concentration, whereas no such patterns exist in a comparable cattle molar from Ketton. Chemical and O isotope variations in the cattle tooth from Empingham II show sympathetic variation of Sr and Ba concentrations with Sr isotope composition from cusp to cervix. The cusp has higher Sr and Ba concentrations log (Sr/Ca) ratio of -3.1 and 87 Sr/ 86 Sr ratio of 0.71151 where as the cervical region of the enamel has log (Sr/Ca) = -3.3 and 87 Sr/ 86 Sr = 0.71061

  10. Anglo-Saxon animal husbandry techniques revealed though isotope and chemical variations in cattle teeth

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J.A. [NERC Isotope Geosciences Laboratory, BGS, Keyworth, Nottingham NG12 5GG (United Kingdom)], E-mail: je@nigl.nerc.ac.uk; Tatham, S. [School of Archaeology and Ancient History, University of Leicester, Leicester LE1 7RH (United Kingdom); Chenery, S.R. [British Geological Survey, Keyworth, Nottingham NG12 5GG (United Kingdom); Chenery, C.A. [NERC Isotope Geosciences Laboratory, BGS, Keyworth, Nottingham NG12 5GG (United Kingdom)

    2007-09-15

    The Sr concentration and isotope composition of tooth enamel from domesticated animals from two neighbouring Anglo-Saxon settlements, at Empingham (6-7th century) and Ketton (10-12th century) in Rutland, central England, are compared both with each other, and with associated human populations. Data from the Empingham II site form discrete fields in Sr concentration and isotope composition space for cattle, pig and sheep with a partial overlap of the human and pig fields. By contrast there is significant overlap in all the animal and human data fields from the Ketton site. The differences in data distribution between the two sites are attributed to animal husbandry techniques, as the surface geology of the two areas is very similar, implying geological factors are an unlikely cause of the difference. It is suggested that the grazing and feeding patterns of animals at the Empingham II site were controlled and restricted, whereas at the Ketton site the animals grazed and foraged freely over a common area. Strontium isotope variation within cattle molars from the two settlements show marked differences that reflect the nature of their feeding and rearing. The enamel from a cattle molar from the Empingham II site has a well-defined, systematic variation of Sr isotope composition with Sr concentration, whereas no such patterns exist in a comparable cattle molar from Ketton. Chemical and O isotope variations in the cattle tooth from Empingham II show sympathetic variation of Sr and Ba concentrations with Sr isotope composition from cusp to cervix. The cusp has higher Sr and Ba concentrations log (Sr/Ca) ratio of -3.1 and {sup 87}Sr/{sup 86}Sr ratio of 0.71151 where as the cervical region of the enamel has log (Sr/Ca) = -3.3 and {sup 87}Sr/{sup 86}Sr = 0.71061.

  11. Hafnium isotope stratigraphy of ferromanganese crusts

    Science.gov (United States)

    Lee; Halliday; Hein; Burton; Christensen; Gunther

    1999-08-13

    A Cenozoic record of hafnium isotopic compositions of central Pacific deep water has been obtained from two ferromanganese crusts. The crusts are separated by more than 3000 kilometers but display similar secular variations. Significant fluctuations in hafnium isotopic composition occurred in the Eocene and Oligocene, possibly related to direct advection from the Indian and Atlantic oceans. Hafnium isotopic compositions have remained approximately uniform for the past 20 million years, probably reflecting increased isolation of the central Pacific. The mechanisms responsible for the increase in (87)Sr/(86)Sr in seawater through the Cenozoic apparently had no effect on central Pacific deep-water hafnium.

  12. Using Nd-Sr isotopes and rare earth elements to study sediment provenance of the modern radial sand ridges in the southwestern Yellow Sea

    International Nuclear Information System (INIS)

    Rao, Wenbo; Mao, Changping; Wang, Yigang; Huang, Huiming; Ji, Junfeng

    2017-01-01

    The radial sand ridges (RSRs) in the southwestern Yellow Sea off the Jiangsu Coast, East China have been intensively studied at least since 1975. Despite decades of studies, the provenance of the RSR sediments remains uncertain. In this study, the Nd-Sr isotopic and REE geochemical compositions of residual sediments (i.e., the acid-insoluble fractions) were investigated to determine the provenance of the RSR sediments. The Nd isotopic composition, PAAS-normalized REE patterns and characteristic parameters (e.g., Sm/Nd, (La/Sm)_N, (Gd/Yb)_N) were merely associated with source rocks but not with particle sorting while the Sr isotopic composition and REE contents of residual sediments were affected by particle sorting in addition to source rocks. The onshore RSR sediments originated mainly from mixing of the fine-grained sediments from various parts of the offshore RSR in terms of REE geochemical and isotopic analyses. Isotopic and REE geochemical comparison further reveals that the RSRs off the Jiangsu Coast were fed chiefly by the dispersal of surface sediments from the Yangtze River Mouth. Surface sediments from the Yangtze River Mouth were directly dispersed to the RSRs along the Jiangsu Coast and significantly affected the seaward part of the offshore RSR and the old Yellow River Delta area by a northward branch of the Changjiang Diluted Freshwater Plume. Only minor quantities of surface sediments from the modern Yellow River Mouth were introduced into the RSRs by the Jiangsu Coastal Current and mainly contaminated the landward part of the offshore RSR area. Our findings highlighted the potential of the Nd isotopes with REE geochemistry to trace the provenance of coastal sediments. - Highlights: • Nd isotopic and REE geochemical compositions of coastal and estuary sediments are mainly associated with source rocks. • Onshore RSR sediments originate from mixing of fine-grained sediments from various parts of the offshore RSR. • The RSRs off the Jiangsu Coast

  13. The radiogenic and stable Sr isotope geochemistry of basalt weathering in Iceland: Role of hydrothermal calcite and implications for long-term climate regulation

    Science.gov (United States)

    Andrews, M. Grace; Jacobson, Andrew D.

    2017-10-01

    Several studies have examined the geochemistry of Icelandic rivers to quantify the relationship between basalt weathering and long-term climate regulation. Recent research has suggested that the chemical weathering of hydrothermal and metamorphic calcite contributes significant quantities of HCO3- to the Icelandic riverine flux (Jacobson et al., 2015). Because the HCO3- derives from volcanic CO2 that was sequestered in mineral form prior to atmospheric injection, the strength of the basalt weathering feedback occurring in Iceland may be lower than previously realized. To test these hypotheses, we analyzed the radiogenic and stable Sr isotope composition (87Sr/86Sr and δ88/86Sr) of the same suite of water, rock, and mineral samples as examined in Jacobson et al. (2015), and we developed a simple model of the long-term C cycle that considers the transformation of volcanic CO2 to HCO3- during subsurface silicate weathering, which is a precursor to hydrothermal calcite formation. Interpretations based on 87Sr/86Sr and Ca/Sr ratios suggest that conservative, three-component mixing between basalt, calcite, and atmospheric deposition adequately explains river geochemistry. On average, the δ88/86Sr values of glacial and non-glacial rivers (0.414‰ and 0.388‰, respectively) are generally higher than those for basalt (0.276‰); however, calcite δ88/86Sr values (0.347‰) are also higher than those for basalt and span the range of riverine values. Thus, riverine δ88/86Sr values are also consistent three-component mixing between basalt, calcite, and atmospheric deposition. Isotopic fractionation is not required to explain riverine trends. Finally, model equations for the long-term C cycle demonstrate that subsurface silicate weathering reduces the magnitude of the volcanic CO2 degassing flux, which in turn causes the atmosphere to stabilize at lower pCO2 values compared to the case where no subsurface silicate weathering occurs. However, the proportion of the net

  14. Strontium isotopes as natural tracers in reservoir oilfield and in groundwater systems

    International Nuclear Information System (INIS)

    Santos, Marcos E.; Palmieri, Helena E.L.; Moreira, Rubens M.

    2009-01-01

    The radioactive beta (β - ) decay of 87 Rb to 87 Sr is an important isotope system that has been widely applied for geochronological purposes and in identifying ground water sources, aquifer interactions and as a tracer for a secondary recovery process in offshore oilfields via seawater injection. The 87 Sr/ 86 Sr ratio of present seawater is constant worldwide, while formation waters in hydrocarbon reservoirs have various values are in most cases higher than modern seawater. This can be the basis for a natural tracer technique aiming at evaluating the performance of seawater injection processes by evaluating the 87 Sr/ 86 Sr ratio and the total Sr content of formation waters in the reservoir prior to injection, followed by monitoring these values in the produced water as injection proceeds. Inductively Couple Plasma Mass Spectrometry ICP-MS is a technique that has potential to be used in studies with tracers in the environment in the determination of isotope ratios and element traces in a sample. This work describes the methodology that will be used for the determination of variations in the isotopic composition of Sr and presents the preliminary results obtained determination of the strontium isotope ratios ( 87 Sr/ 86 Sr) using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). (author)

  15. Zircon U-Pb geochronology and Sr-Nd-Pb-Hf isotopic constraints on the timing and origin of Mesozoic granitoids hosting the Mo deposits in northern Xilamulun district, NE China

    Science.gov (United States)

    Shu, Qihai; Lai, Yong; Zhou, Yitao; Xu, Jiajia; Wu, Huaying

    2015-12-01

    Located in the east section of the Central Asian orogen in northeastern China, the Xilamulun district comprises several newly discovered molybdenum deposits, primarily of porphyry type and Mesozoic ages. This district is divided by the Xilamulun fault into the southern and the northern parts. In this paper, we present new zircon U-Pb dating, trace elements and Hf isotope, and/or whole rock Sr-Nd-Pb isotopic results for the host granitoids from three Mo deposits (Yangchang, Haisugou and Shabutai) in northern Xilamulun. Our aim is to constrain the age and petrogenesis of these intrusions and their implications for Mo mineralization. Zircon U-Pb LA-ICP-MS dating shows that the monzogranites from the Shabutai and Yangchang deposits formed at 138.4 ± 1.5 and 137.4 ± 2.1 Ma, respectively, which is identical to the molybdenite Re-Os ages and coeval well with the other Mo deposits in this region, thereby indicating an Early Cretaceous magmatism and Mo mineralization event. Zircon Ce/Nd ratios from the mineralized intrusions are significantly higher than the barren granites, implying that the mineralization-related magmas are characterized by higher oxygen fugacity. These mineralized intrusions share similar zircon in-situ Hf and whole rock Sr-Nd isotopic compositions, with slightly negative to positive εHf(t) ranging from - 0.8 to + 10.0, restricted εNd(t) values from - 3.7 to + 1.6 but a little variable (87Sr/86Sr)i ratios between 0.7021 and 0.7074, indicative of formation from primary magmas generated from a dominantly juvenile lower crust source derived from depleted mantle, despite diverse consequent processes (e.g., magma mixing, fractional crystallization and crustal contamination) during their evolution. The Pb isotopes (whole rock) also show a narrow range of initial compositions, with (206Pb/204Pb)i = 18.03-18.88, (207Pb/204Pb)i = 15.48-15.58 and (208Pb/204Pb)i = 37.72-38.28, in agreement with Sr-Nd-Hf isotopes reflecting the dominance of a mantle component

  16. Internal bremsstrahlung from 89Sr and 90Sr

    International Nuclear Information System (INIS)

    Sayibaba, T.; Narasimha Murity, K.; Rao, C.R.; Satyaprakash; Gubbi, G.K.

    1987-01-01

    The internal bremsstrahlung (IB) spectra emitted in the beta-decays of 89 Sr and 90 Sr were measured with a HPGe detector and a multichannel analyser along with a standard geometrical set-up. Sufficient care has been taken to avoid spurious effects. After making all the necessary corrections, the experimental results were compared with the corresponding theoretical distributions due to Knipp and Uhlenbeck and Bloch (KUB), Lewis and Ford, Nilsson, and also due to Ford and Martin (detour theory). The total IB yields of intensity and energy from each of the isotopes in the investigated energy regions are also determined and compared with the corresponding theoretical values. The present results of IB from 89 Sr are satisfactorily accounted for by the KUB theory. In the case of 90 Sr the experimental results of IB coincide with the Coulomb-corrected theoretical distibution due to Nilsson in the energy range from 60 keV to 110 keV and Beyond 110 keV, they are found to be in excess over Nilsson's theory as well as the detour theory due to Ford and Martin up to the maximum photon energy studied, namely 350 keV

  17. Assessment of 137Cs and 90Sr Fluxes in the Barents Sea

    Science.gov (United States)

    Matishov, Gennady; Usiagina, Irina; Kasatkina, Nadezhda; Ilin, Gennadii

    2014-05-01

    On the basis of published and own data the annual balance of radionuclide income/outcome was assessed for 137Cs and 90Sr in the Barents Sea for the period from 1950s to the presnt. The scheme of the isotope balance calculation in the Barents Sea included the following processes:atmospheric fallout; river run-off; liquid radioactive wastes releases, income from the Norwegian and the White Seas; outflow to the adjacent areas through the Novaya Zemlya straits and the transects Svalbard-Franz Josef Land and Franz Josef Land-Novaya Zemlya; radioactive decay. According to the multiyear dynamics, the inflow of 137Cs and 90Sr to the Barents Sea was significantly preconditioned by currents from the Norwegian Sea. Three peaks of 137Cs and 90Sr isotope concentrations were registered for the surface waters on the western border of the Barents Sea. The first one was observed in the mid-1960s and was conditioned by testing of nuclear weapons. The increase of isotope concentrations in 1975 and 1980 was preconditioned by the discharge of atomic waste by the Sellafield nuclear reprocessing plant. Nowadays, after the sewage disposal plant was built, the annual discharge of nuclear waste from Sellafield plant is low. The Norwegian Sea was a major source of 137Cs and 90Sr isotope income into the Barents Sea for the period of 1960-2014. Currently, the transborder transfer of 90Sr and 137Cs from the Norwegian Sea into the Barents Sea constitutes about 99% of income for each element. Atmospheric precipitation had a major impact in the 1950-1960s after the testing of the nuclear weapons, and in 1986 after the accident at Chernobyl Nuclear Power Station. In 1963, the atmospheric precipitation of 137Cs reached 1050 TBq; and that of 90Sr, 630 TBq. In 1986, a significant amount of 137Cs inflow (up to 1010 TBq/year) was registered. The 137Cs isotope income exceeded the 90Sr income in the 1960s-1980s, and equal amounts penetrated into the Barents Sea from the Norwegian Sea in the 1990s. Before

  18. Isotopegeochemical investigations and dating on minerals and fossils from sedimentary rocks: 1. Glauconites from Jura, Molasse and Helveticum (K-Ar, Rb-Sr), 2. 87Sr/86Sr-Isotope stratigraphy on marine and limnetic micro- and macro-fossils, 3. Primary minerals from tertiary bentonites and tuffs (U-Pb, K-Ar)

    International Nuclear Information System (INIS)

    Fischer, H.

    1988-01-01

    Glauconite investigations: the main problem in dating glauconites lies in the identification of authigenic minerals which have not been influenced by post-sedimentary processes. The age determination on glauconites from the three different tectonic units: the Jura mountains, the molasse basin and the Helvetic nappes, yield inconsistent results. Up to 35% too young K-Ar ''ages'' of glauconites from limestones from the Helvetic nappes can be traced to partial Ar loss caused by sediment-lithification and tectonic events. Sr-isotope stratigraphy: multiple analyses of recent samples from the Mediterranean Sea and from the North Atlantic show that the 87 Sr/ 86 Sr isotope ratios correspond well. In a stratigraphic ideal section from the Upper marine molasse a resolution of 206 Pb/ 238 U method zircons from the Fish Canyon Tuff were measured and yielded ages of 28.49±0.10, 24.46±0.11 and 28.46±0.13 Ma. These values correspond well with the published mean value of zircon and apatite fission track age of 28.4±0.7 Ma. Thus, the U-Pb method for dating young volcanic minerals seems to be suitable. However, the published mean value (''solid state age'') of Naeser et al. (1981) is higher than the published (''gas age'') mean value of 27.2±0.7 Ma based on biotite, sanidine, hornblende and plagioclase. (author) figs., tabs., refs

  19. Decoupling of Mg-C and Sr-Nd-O isotopes traces the role of recycled carbon in magnesiocarbonatites from the Tarim Large Igneous Province

    Science.gov (United States)

    Cheng, Zhiguo; Zhang, Zhaochong; Hou, Tong; Santosh, M.; Chen, Lili; Ke, Shan; Xu, Lijuan

    2017-04-01

    The Tarim Large Igneous Province in NW China hosts numerous magmatic carbonatite dikes along its northern margin. The carbonatites are composed mainly of dolomite (90 vol.%) and minor calcite (5 vol.%), with apatite, barite, celestine, aegirine, monazite and bastnaesite as accessory minerals. The rocks correspond to magnesiocarbonatites with a compositional range of 13.73-19.59 wt.% MgO, and 20.03-30.11 wt.% CaO, along with 1.65-3.31 wt.% total Fe2O3, 0.02-2.39 wt.% SiO2 and other minor elements, such as P2O5, Na2O and K2O. These magnesiocarbonatites are characterized by extreme enrichment in incompatible elements with high total rare earth element (REE) contents of 372-36965 ppm. The strontium [(87Sr/86Sr)i = 0.70378-0.70386], neodymium [εNd(t) = +2.51 - +3.59] and oxygen (δ18OV-SMOW = 5.9‰-8.0‰) isotope values of these rocks are consistent with a mantle origin, whereas the magnesium (δ26Mg = -1.09‰ to -0.85‰) and carbon (δ13CV-PDB = -4.1‰ to -5.9‰) isotopes are decoupled from mantle values and reflect signature of recycled sedimentary carbonates. Global plate tectonic models predict that sedimentary carbonates in convergent margins are subducted to deep domains in the mantle, with phase transitions from calcite/dolomite to magnesite, and eventually to periclase/perovskite. The involvement of a mantle plume enhances the normal mantle geotherms and promotes decomposition reactions of magnesite. The decoupling of Mg-C and Sr-Nd-O isotopes in the mangesiocarbonatites provides insights on the origin of carbonatites, and also illustrates a case of interaction between mantle plume and subduction-related components.

  20. Seawater strontium isotopes at the Cretaceous-Tertiary boundary

    Science.gov (United States)

    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.

  1. Pb, Sr, Nd, and Hf isotopic constraints on the origin of Hawaiian basalts and evidence for a unique mantle source

    International Nuclear Information System (INIS)

    Stille, P.

    1986-01-01

    Pb, Sr, Nd, and Hf isotopic relationships among basalts from the Hawaiian Islands suggest that these basalts were derived from three sources; the oceanic lithosphere (Kea end member), the depleted asthenosphere (posterosional end member) and a deep-mantle plume (Koolau end member). Hawaiian tholeiites are derived within the lithosphere and the isotopic trends collectively defined by the tholeiite data are interpreted as a plume-lithosphere mixing trend. The isotopic characteristics of late-stage basalts are derived from the tholeiite source (lithosphere + plume) with additional input from the lithosphere, asthenosphere, or both. These basalts probably originate from near the asthenosphere-lithosphere boundary. Posterosional basalts are derived from the depleted asthenosphere, but their isotopic characteristics have been slightly modified by either the plume or the source of previously erupted volcanics. The isotopic data require little or no mixing of asthenospheric material into the plume during tholeiite production and thus are consistent with the concept of a rapidly ascending, fluid-rich plume. In addition to providing a source of heat, the plume may supply volatiles to both the sources of tholeiites and posterosional basalts. The isotopic characteristics of the Koolau (plume) component are unique among OIB sources. If undifferentiated or 'primitive' mantle material still exists, then the radiogenic-isotope data for Koolau in combination with rare gas data for Hawaiian basalts in general suggest that the Hawaiian plume may be derived from such material. In any case, the Hawaiian Islands data, when compared to those of other OIB, serve to illustrate the isotopically diverse nature of mantle sources. (author)

  2. 87Sr/88Sr a useful tool for the identification of geographic origin of Styrian pumpkin seed oils?

    Science.gov (United States)

    Meisel, T.; Bandoniene, D.; Zettl, D.; Maneiko, M.; Horschinegg, M.

    2012-04-01

    The authenticity and the geographic origin of Styrian pumpkin seed oil (PGI) a regional specialty needs to be protected, but the current specification of this high priced product does not include the proof of origin through analytical tools. As it turns out, this and many other products within the Protected Geographical Status (PGS) framework of the European Union, cannot be protected from fraud without forensic tools. In previous studies we were able to demonstrate, that distribution and content of trace elements in particular the rare earth elements, are useful parameters to discriminate Austrian from non-Austrian pumpkin seed oils and seeds. Unlike stable isotopes ratios (C and H), the trace element patterns are not influenced by changes in weather conditions and temperature during growing and harvesting cycle. Though the study of the distribution of element traces can be used not only for the identification of the geographic origin with very useful PLS and PCA models but also can identify fraud through mixing with other oils, this method need to be validated by other means. Radiogenic isotopes, in particular the 87Sr/86Sr isotope amount ratio has been successfully applied to food and other products for forensic studies. In this study we determined the 87Sr/86Sr isotope amount ratio in pumpkin seed oils extracted from seeds of known geographic origin from Austria, Russia and China, as these are the largest producers, to see if significant differences occur and if they can be used as a forensic tool. Although the total area of the Russian and the Chinese crop fields are magnitudes larger than the ones from Austria, it turns out that the variance of the Austrian 87Sr/86Sr data is much larger than that from other sources. Reasons are the large diversity of the Austrian geology (pre-varsican, alpine to sub-recent ages of the underlying bedrock of the soils can be found), the small farm sizes and the small scale production. In Russia large farms are situated on

  3. Calibration of amino acid racemization (AAR) kinetics in United States mid-Atlantic Coastal Plain Quaternary mollusks using 87Sr/ 86Sr analyses: Evaluation of kinetic models and estimation of regional Late Pleistocene temperature history

    Science.gov (United States)

    Wehmiller, J.F.; Harris, W.B.; Boutin, B.S.; Farrell, K.M.

    2012-01-01

    The use of amino acid racemization (AAR) for estimating ages of Quaternary fossils usually requires a combination of kinetic and effective temperature modeling or independent age calibration of analyzed samples. Because of limited availability of calibration samples, age estimates are often based on model extrapolations from single calibration points over wide ranges of D/L values. Here we present paired AAR and 87Sr/ 86Sr results for Pleistocene mollusks from the North Carolina Coastal Plain, USA. 87Sr/ 86Sr age estimates, derived from the lookup table of McArthur et al. [McArthur, J.M., Howarth, R.J., Bailey, T.R., 2001. Strontium isotopic stratigraphy: LOWESS version 3: best fit to the marine Sr-isotopic curve for 0-509 Ma and accompanying Look-up table for deriving numerical age. Journal of Geology 109, 155-169], provide independent age calibration over the full range of amino acid D/L values, thereby allowing comparisons of alternative kinetic models for seven amino acids. The often-used parabolic kinetic model is found to be insufficient to explain the pattern of racemization, although the kinetic pathways for valine racemization and isoleucine epimerization can be closely approximated with this function. Logarithmic and power law regressions more accurately represent the racemization pathways for all amino acids. The reliability of a non-linear model for leucine racemization, developed and refined over the past 20 years, is confirmed by the 87Sr/ 86Sr age results. This age model indicates that the subsurface record (up to 80m thick) of the North Carolina Coastal Plain spans the entire Quaternary, back to ???2.5Ma. The calibrated kinetics derived from this age model yield an estimate of the effective temperature for the study region of 11??2??C., from which we estimate full glacial (Last Glacial Maximum - LGM) temperatures for the region on the order of 7-10??C cooler than present. These temperatures compare favorably with independent paleoclimate information

  4. The crust role at Paramillos Altos intrusive belt: Sr and Pb isotope evidence

    International Nuclear Information System (INIS)

    Ostera, H.A.; Linares, E; Haller, M.J; Cagnoni, M.C

    2001-01-01

    Paramillos Altos Intrusive Belt (PAIB) (Ostera, 1996) is located in the thick skinned folded-thrust belt of Malargue, southwestern Mendoza, Argentina. Geochemical, geochronologic and isotopic studies were carried out in it (Ostera 1996, 1997, Ostera et al. 1999; Ostera et al. 2000) and these previous papers suggested a minor involvement of the crust in the genesis of the PAIB. According with Ostera et al. (2000) it is composed by stocks, laccoliths, dykes and sills which range in composition from diorites to granodiorites, and from andesites to rhyolites, and divided in five Members, which range in age from Middle Miocene to Early Miocene: a- Calle del Yeso Dyke Complex (CYDC), with sills and dykes of andesitic composition (age: 20±2 Ma). b- Puchenque-Atravesadas Intrusive Complex (PAIC), composed by dykes and stocks ranging from diorites to granodiorites (age: 12.5±1 Ma). c- Arroyo Serrucho Stock (SAS), an epizonal and zoned stock, with four facies, with K/Ar and Ar/Ar dates of 10±1 and 9.5±0.5 Ma. d- Portezuelo de los Cerros Bayos (PCB), that includes porphyritic rocks of rhyolitic composition, of 7.5±0.5 Ma. e- Cerro Bayo Vitrophyres (CBV), with andesitic sills and dykes (age: 4.8±0.2 Ma). We present in this paper new Sr and Pb isotopes data that constrain the evolution of the PAIB (au)

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

    Science.gov (United States)

    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.

  6. Isotopic Tracers to Identify Far-traveled Pollutant and Mineral Aerosols in Northern California (Invited)

    Science.gov (United States)

    Depaolo, D. J.; Christensen, J. N.; Ewing, S. A.; Cliff, S. S.; Brown, S. T.; Vancuren, R. A.

    2009-12-01

    .g., Pb, Sr, Nd isotopes), the precision and sensitivity of geographic attribution is increased, and different aerosol components can be targeted (e.g., Pb for industrial particulates, Sr and Nd for mineral dust). Isotopes can also give information about aerosol alteration during transport. As an illustration of these points we will present the results of a time series of isotopic (Pb and Sr), and chemical data for samples collected at several sites in California over the past 1.5 years. In this case the proportion of airborne Pb originating from Asia can be tracked accurately, and shown to vary seasonally and even weekly. The isotopic approach is sufficiently sensitive that the proportion of Asian Pb can be determined even close to urban areas where overall loading is high and local sources are strong. Sr isotopes provide other information, such as the effects of admixed marine aerosols, and based on samples collected in Asia, how materials from different Asian sources are mixed prior to crossing the Pacific.

  7. U/Pb zircon dating and Sr and Nd isotope characteristics of Permian volcanism in the Western Pyrenees: the Ossau and Anayet Massif. Datation U/Pb sur zircon et geochimie isotopique Sr et Nd du volcanisme permien des Pyrenees Occidentales (Ossau et Anayet)

    Energy Technology Data Exchange (ETDEWEB)

    Briqueu, L [Montpellier-2 Univ., 34 (France); Innocent, C [Aix-Marseille-3 Univ., 13 - Marseille (France)

    1993-03-01

    Several zircon populations have been extracted from a peraluminous rhyolite and from a dacite which are the rock types characteristic of the first two volcanic phases of the Pic du Midi d'Ossau (Eastern Pyrenees). Using a Concordia Diagram, their U/Pb isotopic study confirms that volcanism started in the Autunian age (272 to 278 My). These two volcanic cycles display initial Sr and Nd isotopic signatures which are comparable, and show a strong crustal imprint. Volcanism subsequently evolves towards an increasingly alkaline composition and the corresponding isotopic characteristics are compatible with a depleted asthenospheric mantle source.

  8. Strontium isotope geochemistry of alluvial groundwater: a tracer for groundwater resources characterisation

    Directory of Open Access Journals (Sweden)

    P. Négrel

    2004-01-01

    Full Text Available This study presents strontium isotope and major ion data of shallow groundwater and river water from the Ile du Chambon catchment, located on the Allier river in the Massif Central (France. There are large variations in the major-element contents in the surface- and groundwater. Plotting of Na vs. Cl contents and Ca, Mg, NO3, K, SO4, HCO3, Sr concentrations reflect water–rock interaction (carbonate dissolution for Ca, Mg, HCO3 and Sr because the bedrock contains marly limestones, agricultural input (farming and fertilising and sewage effluents (for NO3, K, SO4, although some water samples are unpolluted. Sr contents and isotope ratios (87Sr/86Sr vary from 0.70892 to 0.71180 along the hydrological cycle in the groundwater agree with previous work on groundwater in alluvial aquifers in the Loire catchment. The data plot along three directions in a 87Sr/86Sr v. 1/Sr diagram as a result of mixing, involving at least three geochemical signatures–Allier river water, and two distinct signatures that might be related to different water-rock interactions in the catchment. Mixing proportions are calculated and discussed. The alluvial aquifer of the Ile du Chambon catchment is considered, within the Sr isotope systematic, in a larger scheme that includes several alluvial aquifers of the Loire Allier catchment. Keywords: : Loire river, major and trace elements, Sr isotopic ratio, alluvial aquifer, hydrology

  9. Sr-Nd isotopic characteristic, U-Pb zircon geochronology, and petrogenesis of Najmabad Granodiorite batholith, Eastern Iran

    Directory of Open Access Journals (Sweden)

    Mehrab Moradi

    2011-11-01

    Full Text Available The study area is located south of Ghonabad in Eastern Iran. This area is situated between two major faults, Darouneh to the north and Dashtbyaz to the south. The movements of these faults cased major dislocation of this block. Najmabad granodiorite to granite batholith is elongated trending east-west 2×8 Km2. Mineralization is associated with granite and monzonite. Alteration zones are: propylitic, sericitic, argillic and silicification. Chemically, granite-granodiorite is met-aluminous,, spider diagram normalized to lower continental crust show enrichment of LILE such as Rb, Cs, K and LREE (La, Ce , depletion of Ti, Sr, Ta, Nb, Ba, Cs. Based on low values of magnetic susceptibility [(5 to 11 × 10-5 SI], therefore it is classified as belonging to the ilmenite-series (reduced type. The result of U-Pb zircon age dating of granodiorite is 161.85 Ma (Middle Jurassic, Callovian time. Based on Initial εNd isotope values for granodiorite is -6.51, initial 87Sr/86Sr and 143Nd/144Nd ratios for granodiorite is (0.70913 and 0.512095, the magma for granite and granodiorite originated from the continental crust. During Middle Jurassic (Callovian due to continental collision, Upper Triassic to Lower Jurassic rocks is regionally metamorphosed. During the continental collision, Middle Jurassic (164-162Ma reduced type granitoid magma (Ilmenite series, continental crust melting formed and intruded these regional metamorphosed rock in Najmabad, Shah Kuh and Sorkh Kuh area.

  10. Strontium isotope data for recent andesites in Ecuador and North Chile

    International Nuclear Information System (INIS)

    Francis, P.W.; Thorpe, R.S.; Moorbath, S.

    1977-01-01

    New Sr isotope data are presented for andesite lavas from active volcanoes in Ecuador and North Chile. Twenty-three samples from five Ecuadorian volcanoes have 87 Sr/ 86 Sr ratios most of which are essentially within analytical error, and average 0.7044. In contrast, 16 samples from the San Pedro-San Pablo volcano complex in North Chile have 87 Sr/ 86 Sr ratios between 0.7058 and 0.7072. These samples show no correlation between 87 Sr/ 86 Sr and 87 Rb/ 86 Sr, nor between 87 Sr/ 86 Sr and other elements or ratios. The major difference in setting between the two volcanic provinces lies in the thickness of the continental crust; 40-50 km beneath Ecuador, 70 km beneath North Chile. Andesites from both areas are derived primarily from the mantle, but those from North Chile show evidence of a significant Sr isotopic contribution from the continental crust. (Auth.)

  11. Accurate γ-ray spectrometry measurements of the half-life of 92Sr

    International Nuclear Information System (INIS)

    Leconte, P.; Hudelot, J.P.; Antony, M.

    2008-01-01

    Studies of the nuclear fuel cycle require an accurate knowledge of the energy release from the decay of radioactive nuclides produced in a reactor, including precise half-life data for the short-lived radionuclides. Moreover, short-lived fission products are crucial for fission rate distribution measurements performed in low-power facilities, such as EOLE and MINERVE of CEA Cadarache [Fougeras, P., 2005. EOLE, MINERVE and MASURCA facilities and their associated neutron experimental programs. In: 13th International Conference on Nuclear Engineering, Beijing, China, 16-20 May 2005], and their nuclear decay data need to be known to high precision. For these reasons, the half-life of 92 Sr has been measured to solve a recently observed inconsistency identified with the quoted value in the main nuclear applications libraries (including JEFF3.1): T 1/2 =2.71±0.01 h [Parsa, B., Ashari, A., Goolvard, L., Nobar, Y.M., 1971. Decay scheme of 2.71 h 92 Sr. Nucl. Phys. A 175, 629-640]. An overestimation of 4.5% has been identified in this work, based on two independent methods. Specific γ-ray spectrometry measurements on activated fissile foils have been carried out, using two HPGe detectors. Influencing factors such as net area measurements of photopeaks, pulse pile-up accuracy and dead time corrections in the presence of decaying activity are discussed. A new value has been obtained by combining eight series of measurements: T 1/2 =2.594±0.006 h. The uncertainty has been reduced by a factor of two with respect to previous evaluations. This measured value also shows good agreement with the most recent studies of T 1/2 =2.627±0.009 h [Nir-El, Y., 2003. Private Communications. Soreq Research Centre, Yavne, Israel

  12. Carboniferous climate teleconnections archived in coupled bioapatite δ18OPO4 and 87Sr/86Sr records from the epicontinental Donets Basin, Ukraine

    Science.gov (United States)

    Montanez, Isabel P.; Osleger, Dillon J.; Chen, J.-H.; Wortham, Barbara E.; Stamm, Robert G.; Nemyrovska, Tamara I.; Griffin, Julie M.; Poletaev, Vladislav I.; Wardlaw, Bruce R.

    2018-01-01

    Reconstructions of paleo-seawater chemistry are largely inferred from biogenic records of epicontinental seas. Recent studies provide considerable evidence for large-scale spatial and temporal variability in the environmental dynamics of these semi-restricted seas that leads to the decoupling of epicontinental isotopic records from those of the open ocean. We present conodont apatite δ18OPO4 and 87Sr/86Sr records spanning 24 Myr of the late Mississippian through Pennsylvanian derived from the U–Pb calibrated cyclothemic succession of the Donets Basin, eastern Ukraine. On a 2 to 6 Myr-scale, systematic fluctuations in bioapatite δ18OPO4 and 87Sr/86Sr broadly follow major shifts in the Donets onlap–offlap history and inferred regional climate, but are distinct from contemporaneous more open-water δ18OPO4 and global seawater Sr isotope trends. A −1 to −6‰ offset in Donets δ18OPO4 values from those of more open-water conodonts and greater temporal variability in δ18OPO4 and 87Sr/86Sr records are interpreted to primarily record climatically driven changes in local environmental processes in the Donets sea. Systematic isotopic shifts associated with Myr-scale sea-level fluctuations, however, indicate an extrabasinal driver. We propose a mechanistic link to glacioeustasy through a teleconnection between high-latitude ice changes and atmospheric pCO2 and regional monsoonal circulation in the Donets region. Inferred large-magnitude changes in Donets seawater salinity and temperature, not archived in the more open-water or global contemporaneous records, indicate a modification of the global climate signal in the epicontinental sea through amplification or dampening of the climate signal by local and regional environmental processes. This finding of global climate change filtered through local processes has implications for the use of conodont δ18OPO4 and 87Sr/86Sr values as proxies of paleo-seawater composition, mean temperature, and glacioeustasy.

  13. Carboniferous climate teleconnections archived in coupled bioapatite δ18OPO4 and 87Sr/86Sr records from the epicontinental Donets Basin, Ukraine

    Science.gov (United States)

    Montañez, Isabel P.; Osleger, Dillon J.; Chen, Jitao; Wortham, Barbara E.; Stamm, Robert G.; Nemyrovska, Tamara I.; Griffin, Julie M.; Poletaev, Vladislav I.; Wardlaw, Bruce R.

    2018-06-01

    Reconstructions of paleo-seawater chemistry are largely inferred from biogenic records of epicontinental seas. Recent studies provide considerable evidence for large-scale spatial and temporal variability in the environmental dynamics of these semi-restricted seas that leads to the decoupling of epicontinental isotopic records from those of the open ocean. We present conodont apatite δ18OPO4 and 87Sr/86Sr records spanning 24 Myr of the late Mississippian through Pennsylvanian derived from the U-Pb calibrated cyclothemic succession of the Donets Basin, eastern Ukraine. On a 2 to 6 Myr-scale, systematic fluctuations in bioapatite δ18OPO4 and 87Sr/86Sr broadly follow major shifts in the Donets onlap-offlap history and inferred regional climate, but are distinct from contemporaneous more open-water δ18OPO4 and global seawater Sr isotope trends. A -1 to -6‰ offset in Donets δ18OPO4 values from those of more open-water conodonts and greater temporal variability in δ18OPO4 and 87Sr/86Sr records are interpreted to primarily record climatically driven changes in local environmental processes in the Donets sea. Systematic isotopic shifts associated with Myr-scale sea-level fluctuations, however, indicate an extrabasinal driver. We propose a mechanistic link to glacioeustasy through a teleconnection between high-latitude ice changes and atmospheric pCO2 and regional monsoonal circulation in the Donets region. Inferred large-magnitude changes in Donets seawater salinity and temperature, not archived in the more open-water or global contemporaneous records, indicate a modification of the global climate signal in the epicontinental sea through amplification or dampening of the climate signal by local and regional environmental processes. This finding of global climate change filtered through local processes has implications for the use of conodont δ18OPO4 and 87Sr/86Sr values as proxies of paleo-seawater composition, mean temperature, and glacioeustasy.

  14. High-precision measurement of variations in calcium isotope ratios in urine by multiple collector inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Morgan, J.L.L.; Gordon, G.W.; Arrua, R.C.; Skulan, J.L.; Anbar, A.D.; Bullen, T.D.

    2011-01-01

    We describe a new chemical separation method to isolate Ca from other matrix elements in biological samples, developed with the long-term goal of making high-precision measurement of natural stable Ca isotope variations a clinically applicable tool to assess bone mineral balance. A new two-column procedure utilizing HBr achieves the purity required to accurately and precisely measure two Ca isotope ratios (44Ca/42Ca and 44Ca/43Ca) on a Neptune multiple collector inductively coupled plasma mass spectrometer (MC-ICPMS) in urine. Purification requirements for Sr, Ti, and K (Ca/Sr > 10000; Ca/Ti > 10000000; and Ca/K > 10) were determined by addition of these elements to Ca standards of known isotopic composition. Accuracy was determined by (1) comparing Ca isotope results for samples and standards to published data obtained using thermal ionization mass spectrometry (TIMS), (2) adding a Ca standard of known isotopic composition to a urine sample purified of Ca, and (3) analyzing mixtures of urine samples and standards in varying proportions. The accuracy and precision of δ44/42Ca measurements of purified samples containing 25 μg of Ca can be determined with typical errors less than ±0.2‰ (2σ).

  15. Crustal contamination and crystal entrapment during polybaric magma evolution at Mt. Somma-Vesuvius volcano, Italy: Geochemical and Sr isotope evidence

    Science.gov (United States)

    Piochi, M.; Ayuso, R.A.; de Vivo, B.; Somma, R.

    2006-01-01

    New major and trace element analyses and Sr-isotope determinations of rocks from Mt. Somma-Vesuvius volcano produced from 25 ky BP to 1944 AD are part of an extensive database documenting the geochemical evolution of this classic region. Volcanic rocks include silica undersaturated, potassic and ultrapotassic lavas and tephras characterized by variable mineralogy and different crystal abundance, as well as by wide ranges of trace element contents and a wide span of initial Sr-isotopic compositions. Both the degree of undersaturation in silica and the crystal content increase through time, being higher in rocks produced after the eruption at 472 AD (Pollena eruption). Compositional variations have been generally thought to reflect contributions from diverse types of mantle and crust. Magma mixing is commonly invoked as a fundamental process affecting the magmas, in addition to crystal fractionation. Our assessment of geochemical and Sr-isotopic data indicates that compositional variability also reflects the influence of crustal contamination during magma evolution during upward migration to shallow crustal levels and/or by entrapment of crystal mush generated during previous magma storage in the crust. Using a variant of the assimilation fractional crystallization model (Energy Conservation-Assimilation Fractional Crystallization; [Spera and Bohrson, 2001. Energy-constrained open-system magmatic processes I: General model and energy-constrained assimilation and fractional crystallization (EC-AFC) formulation. J. Petrol. 999-1018]; [Bohrson, W.A. and Spera, F.J., 2001. Energy-constrained open-system magmatic process II: application of energy-constrained assimilation-fractional crystallization (EC-AFC) model to magmatic systems. J. Petrol. 1019-1041]) we estimated the contributions from the crust and suggest that contamination by carbonate rocks that underlie the volcano (2 km down to 9-10 km) is a fundamental process controlling magma compositions at Mt. Somma

  16. The effect of secondary apatite on the initial 87Sr/86Sr ratio determination in granitic rocks: a case study of the Tadamigawa pluton, northeastern Japan

    Science.gov (United States)

    Wakasugi, Y.; Ichino, K.; Tanioka, Y.; Wakaki, S.; Tsuboi, M.; Ishikawa, T.

    2017-12-01

    Apatite is a major accessory mineral in igneous rocks. Because Rb contents in apatite are very low, 87Sr/86Sr ratios of magmatic apatite are useful to estimate the initial 87Sr/86Sr ratio (SrI) of igneous rocks. Secondary post-magmatic event such as hydrothermal alteration may also crystallize secondary apatite, which may inhibit the estimation of SrI of igneous rocks. In this study, we examine the effects of secondary apatite on the initial 87Sr/86Sr ratio determination of granitic rocks by using acid leaching technique. Leached apatite samples were first separated from the whole rock powder as a heavy mineral fraction by heavy liquid technique, and the heavy mineral fraction was then leached by 3 M HNO3. The isotopic ratios of Sr and the concentrations of Rb and Sr were analyzed by TIMS and ICP-MS at Kochi Core Center, respectively. The Tadamigawa Older-stage granites, which locate in the Taishaku Mountains at the northeastern part of Japan, intrude into the Ashio Jurassic complex, and the ages of these rocks are late Cretaceous to Paleogene. The U-Pb ages of zircon and the K-Ar ages of biotite for these rocks are c. 100 Ma [1, 2]. Rb-Sr whole-rock isochron age of the pluton is 96.5 ± 1.3 Ma (SrI = 0.70534 ± 0.00003) and it is concordant with other radiometric ages. Rb-Sr mineral isochron ages range from 84.4 to 97.3 Ma and these ages are relatively younger than the Rb-Sr whole-rock isochron age. The difference among radiometric ages may reflect the difference of the closure temperature in each isotopic system. The Tadamigawa Older-stage granites have SrI for Rb-Sr mineral isochron range from 0.7053 to 0.7061 and are very similar to that (0.70534) for Rb-Sr whole-rock isochron. These may suggest that the Tadamigawa Older-stage granites are generated from same parental magma. However, 87Sr/86Sr ratios of the leached apatite samples were 0.70544-0.70856 and are relatively higher than SrI obtained from the Rb-Sr mineral isochrons (0.7053-0.7061). This result

  17. The composition and distribution of the rejuvenated component across the Hawaiian plume: Hf-Nd-Sr-Pb isotope systematics of Kaula lavas and pyroxenite xenoliths

    Science.gov (United States)

    Bizimis, Michael; Salters, Vincent J. M.; Garcia, Michael O.; Norman, Marc D.

    2013-10-01

    Rejuvenated volcanism refers to the reemergence of volcanism after a hiatus of 0.5-2 Ma following the voluminous shield building stage of Hawaiian volcanoes. The composition of the rejuvenated source and its distribution relative to the center of the plume provide important constraints on the origin of rejuvenated volcanism. Near-contemporaneous lavas from the Kaula-Niihau-Kauai ridge and the North Arch volcanic field that are aligned approximately orthogonally to the plume track can constrain the lateral geochemical heterogeneity and distribution of the rejuvenated source across the volcanic chain. Nephelinites, phonolites and pyroxenite xenoliths from Kaula Island have radiogenic Hf, Nd and unradiogenic Sr isotope compositions consistent with a time-integrated depleted mantle source. The pyroxenites and nephelinites extend to the lowest 208Pb/204Pb reported in Hawaiian rocks. These data, along with new Pb isotope data from pyroxenites from the Salt Lake Crater (Oahu) redefine the composition of the depleted end-member of the Hawaiian rejuvenated source at 208Pb/204Pb=37.35±0.05, 206Pb/204Pb = 17.75±0.03, ɛNd = 9-10, ɛHf ˜16-17 and 87Sr/88Sr Niihau-Kauai-North Arch transect are consistent with a larger proportion of the rejuvenated depleted component in the periphery of the plume track rather than along its axis.

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

    Science.gov (United States)

    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.

  19. The Strontium Fingerprint and Footprint: Using 87Sr/86Sr to Find the Sources and Range of Architectural Timber Acquisition of Great House Construction at Chaco Canyon, New Mexico

    Science.gov (United States)

    English, N. B.; Reynolds, A. C.; Quade, J.; Betancourt, J. L.

    2006-12-01

    We describe the spatial and temporal patterns of timber acquisition by great house builders in Chaco Canyon, New Mexico. The 87Sr/86Sr ratios from annually-dated, architectural logs in 10^{th} to 12^{th} century structures are compared to the 87Sr/86Sr of modern tree stands from the surrounding mountains. Although not a stable isotope system, the long half-life of the 87Sr parent (87Rb, t1/2 = 48.8 Ga) yields a stable isotope system on the timescales used to determine the geographic origin of ecosystem resources. The small mass difference among strontium's isotopes eliminates measurable biologic or kinetic fractionation at earth surface conditions. Strontium tracer studies, however, do require distinct end-member ratios to be feasible. Strontium isotopes, alone or in combination with other isotopes, provide a simple way to study and trace the geographic origin of ecosystem resources. Over the 150 km-wide Chaco Basin, 87Sr/86Sr ratios of modern trees range from 0.7055 to 0.7192. 87Sr/86Sr ratios from this and other studies show that during great house construction Chaco Canyon was provisioned with plant materials that came from more than 75 km away in all directions. This includes (1) corn (Zea mays) grown on the eastern flanks of the Chuska Mountains and floodplain of the San Juan River to the west and north, (2) spruce (Picea sp.) and fir (Abies sp.) architectural beams from the high crests of the Chuska and San Mateo Mountains to the west and south, and (3) ponderosa pine (Pinus ponderosa) from the low slopes of the La Platas and San Juan Mountains to the north, the San Pedro Mountains to the east, the Chuska and San Mateo Mountains and nearby mesas. There are no systematic patterns in spruce/fir or ponderosa provenance by great house (Pueblo Bonito, Chetro Ketl, Pueblo del Arroyo) or by time, suggesting the use of stockpiles from a few preferred sources from the beginning of large scale construction in or around Chaco Canyon. This is contrary to the view that

  20. Petrogenesis and tectonic implications of Late Devonian arc volcanic rocks in southern Beishan orogen, NW China: Geochemical and Nd-Sr-Hf isotopic constraints

    Science.gov (United States)

    Guo, Qian-Qian; Chung, Sun-Lin; Xiao, Wen-Jiao; Hou, Quan-Lin; Li, Shan

    2017-05-01

    Late Devonian (ca. 370 Ma) volcanic rocks provide important information about the nature of magmatism during the tectonic transition between the Early and Late Paleozoic in the Beishan orogen, southern Central Asian Orogenic Belt. They are predominantly an andesitic-dacitic-rhyolitic assemblage, characterized by alkali contents ranging from slightly calcic to slightly alkaline. The rhyolitic rocks are generally ferroan, whereas the andesitic rocks are magnesian. These volcanic rocks exhibit similar trace element characteristics to those of continental arcs. Strongly negative εNd(t) values (- 2.8 to - 3.6) and high Sr isotopic compositions (initial 87Sr/86Sr = 0.7036-0.7108) suggest that they are mainly derived from an ancient crust. However, the positive zircon εHf(t) values (+ 1.4 to + 16.4) support the role of juvenile components in their genesis, indicating the significant input of new mantle-derived magmas. These characteristics imply a hybrid derivation, from an ancient crustal source with the addition of juvenile materials during magma genesis, or perhaps heterogeneous contamination or hybridization during magma emplacement. Combined with the regional geology, our results indicate that the Late Devonian magmatism resulted from a southward retreat of the subduction zone, which records significant continental crustal growth in a transitional arc or an accretionary arc setting. The distinct geochemical compositions, especially the Nd-Hf isotope decoupling of the Dundunshan volcanic rocks, imply a significant change in the geodynamic setting in the Late Paleozoic.

  1. Rb-Sr and K-Ar isotopic evidence for neoproterozoic (Pan-African) granulite metamorphism from the basement of Mumbai offshore basin, India

    International Nuclear Information System (INIS)

    Rathore, S.S.; Vijan, A.R.; Singh, M.P.; Misra, K.N.; Prabhu, B.N.

    2000-01-01

    Precambrian basement from well HBM-1 in the Heera oil field of Mumbai offshore basin has been dated by Rb-Sr and K-Ar methods. Five granulitic basement samples from three conventional drill cores have yielded Rb-Sr isochron age of 502±25 Ma with an initial Sr ratio of 0.70855±0.00013. This age has been interpreted as the time of granulite facies metamorphism of the basement rocks in the region. Two whole rock samples from the basement of this well have yielded mutually concordant K-Ar ages of 505±16 Ma and 507±17 Ma. The K-Ar ages are significantly similar to Rb-Sr age obtained from this well, suggesting complete isotopic reequilibration around 500 Ma ago. The time of secondary thermal heating around 500 Ma ago in the basement of Heera field coincides with the widespread neoproterozoic (Pan-African) thermo-tectonic event extending from the Arabian Peninsula and eastern Africa covering Madagascar, southern India. Sri Lanka and East Antarctica. This study widens the limit of the Pan-African zone, which hitherto was thought to be confined to the western part (presently southern part) of the Indian subcontinent, towards further east. (author)

  2. Anthropogenic versus natural control on trace element and Sr-Nd-Pb isotope stratigraphy in peat sediments of southeast Florida (USA), ˜1500 AD to present

    Science.gov (United States)

    Kamenov, George D.; Brenner, Mark; Tucker, Jaimie L.

    2009-06-01

    is oil combustion. The decline in V accumulation after 1970 in the BCM peat corresponds to the introduction of low-sulfur fuels and the change from heavy to distilled oils since the 1970s. After the 1920s, Pb distribution in the peat follows closely the history of alkyl lead consumption in the US, which peaked in the 1970s. Pb isotopes support this inference and furthermore, record changes in the ore sources used to produce leaded gasoline. Idaho ores dominated the peat Pb isotope record until the 1960s, followed by Pb from Mississippi Valley Type deposits from the 1960s to the 1980s. Enhanced fluxes of Cu, Zn, Cd, Sn, Sb, Bi, and to some extent Ni during the last century are likely also related to fossil fuel combustion. Local agricultural activities may also have influenced the geochemical cycles of Cu and Zn. The peat record shows enhanced U accumulation during the last century, possibly related to phosphate mining in western Florida. Sr isotopes in the peat core also reflect anthropogenic influence. The 87Sr/ 86Sr ratio decreases from natural background values in the basal part of the core to lower values in the upper part of the core. The Sr isotope shift is probably related to quarrying operations in Florida, and marks the first time an anthropogenic signal has been detected using the Sr isotope record in a peat core.

  3. Hydrologic and environmental controls on uranium-series and strontium isotope ratios in a natural weathering environment

    Science.gov (United States)

    White, A. M.; Ma, L.; Moravec, B. G.; McIntosh, J. C.; Chorover, J.

    2017-12-01

    In a remote, volcanic headwater catchment of the Jemez River Basin Critical Zone Observatory (JRB-CZO) in NM, stable water isotopes and solute chemistry have shown that snowmelt infiltrates and is stored before later discharging into springs and streams via subsurface flowpaths that vary seasonally. Therefore, water-rock reactions are also expected to change with season as hydrologic flowpaths transport water, gases and solutes through different biogeochemical conditions, rock types and fracture networks. Uranium-series isotopes have been shown to be a novel tracer of water-rock reactions and source water contributions while strontium isotopes are frequently used as indicators of chemical weathering and bedrock geology. This study combines both isotopes to understand how U and Sr isotope signatures evolve through the Critical Zone (CZ). More specifically, this work examines the relationship between seasonality, water transit time (WTT), and U-series and Sr isotopes in stream and spring waters from three catchments within the JRB-CZO, as well as lithology, rock type and CZ structure in solid phase cores. Samples from ten springs with known WTTs were analyzed for U and Sr isotopes to determine the effect of WTT on the isotopic composition of natural waters. Results suggest that WTT alone cannot explain the variability of U and Sr isotopes in JRB-CZO springs. Stream samples were also collected across two water years to establish how seasonality controls surface water isotopic composition. U and Sr isotope values vary with season, consistent with a previous study from the La Jara catchment; however, this study revealed that these changes do not show a systematic pattern among the three catchments suggesting that differences in the mineralogy and structure of the deep CZ in individual catchments, and partitioning of water along deep vs surficial and fracture vs matrix flow paths, likely also control isotopic variability. The distribution of U-series and Sr isotopes in

  4. Across-arc versus along-arc Sr-Nd-Pb isotope variations in the Ecuadorian volcanic arc

    Science.gov (United States)

    Ancellin, Marie-Anne; Samaniego, Pablo; Vlastélic, Ivan; Nauret, François; Gannoun, Adbelmouhcine; Hidalgo, Silvana

    2017-03-01

    Previous studies of the Ecuadorian arc (1°N-2°S) have revealed across-arc geochemical trends that are consistent with a decrease in mantle melting and slab dehydration away from the trench. The aim of this work is to evaluate how these processes vary along the arc in response to small-scale changes in the age of the subducted plate, subduction angle, and continental crustal basement. We use an extensive database of 1437 samples containing 71 new analyses, of major and trace elements as well as Sr-Nd-Pb isotopes from Ecuadorian and South Colombian volcanic centers. Large geochemical variations are found to occur along the Ecuadorian arc, in particular along the front arc, which encompasses 99% and 71% of the total variations in 206Pb/204Pb and 87Sr/86Sr ratios of Quaternary Ecuadorian volcanics, respectively. The front arc volcanoes also show two major latitudinal trends: (1) the southward increase of 207Pb/204Pb and decrease of 143Nd/144Nd reflect more extensive crustal contamination of magma in the southern part (up to 14%); and (2) the increase of 206Pb/204Pb and decrease of Ba/Th away from ˜0.5°S result from the changing nature of metasomatism in the subarc mantle wedge with the aqueous fluid/siliceous slab melt ratio decreasing away from 0.5°S. Subduction of a younger and warmer oceanic crust in the Northern part of the arc might promote slab melting. Conversely, the subduction of a colder oceanic crust south of the Grijalva Fracture Zone and higher crustal assimilation lead to the reduction of slab contribution in southern part of the arc.

  5. Depletion, cryptic metasomatism, and modal metasomatism (refertilization) of Variscan lithospheric mantle: Evidence from major elements, trace elements, and Sr-Nd-Os isotopes in a Saxothuringian garnet peridotite

    Czech Academy of Sciences Publication Activity Database

    Medaris Jr., L. G.; Ackerman, Lukáš; Jelínek, E.; Michels, Z. D.; Erban, V.; Kotková, J.

    2015-01-01

    Roč. 226, SI (2015), s. 81-97 ISSN 0024-4937 Institutional support: RVO:67985831 Keywords : garnet peridotite * Variscan * Bohemian Massif * Sr-Nd-Os isotopes * depletion cryptic metasomatism and refertilization * P-T conditions Subject RIV: DD - Geochemistry Impact factor: 3.723, year: 2015

  6. The Rb-Sr system

    International Nuclear Information System (INIS)

    Graham, I.J.

    1983-11-01

    This manual is intended to serve as a guide to the chemical procedures involved in Rb-Sr isotopic analysis as conducted at the Institute of Nuclear Sciences. Included are notes on the experimental developments made over the last 2.5 years, especially those involving rock dissolution and cation exchange chromatography

  7. Petrogenesis and geodynamic implications of Ediacaran highly fractionated A-type granitoids in the north Arabian-Nubian Shield (Egypt): Constraints from whole-rock geochemistry and Sr-Nd isotopes

    Science.gov (United States)

    Sami, Mabrouk; Ntaflos, Theodoros; Farahat, Esam S.; Mohamed, Haroun A.; Hauzenberger, Christoph; Ahmed, Awaad F.

    2018-04-01

    Mineral chemistry, whole-rock geochemical and Sr-Nd isotopic data are reported for the Abu-Diab granitoids in the northern Arabian-Nubian Shield (ANS) of Egypt, to investigate their petrogenesis and geodynamic significance. Gabal Abu-Diab constitute a multiphase pluton, consisting largely of two-mica granites (TMGs) enclosing microgranular enclaves and intruded by garnet bearing muscovite granites (GMGs) and muscovite granites (MGs). The granitoids are weakly peraluminous (A/CNK = 1.01-1.12) and show high SiO2 (>72.9 wt%) and alkali (K2O + Na2O = 8.60-9.13) contents. The geochemical features show that they are post-collisional and highly fractionated A-type granitoids. Compared to their host TMGs, the microgranular enclaves are strongly peraluminous (A/CNK = 1.18-1.24) with lower SiO2 and higher abundances of trace elements. The TMGs are depleted in Ba, Nb, P and Ti and are enriched in LREEs relative to HREEs with weakly negative Eu anomalies (Eu/Eu* = 0.45-0.64). In contrast, the GMGs and MGs are extremely depleted in Ba, Sr and Ti and have tetrad-type REE patterns (TE1-3 = 1.1-1.3) with strongly pronounced negative Eu anomalies (Eu/Eu* = 0.03-0.26), similar to rare metals bearing granites. The Ediacaran (585 ± 24 Ma) TMGs, are characterized by restricted and relatively low initial 87Sr/86Sr ratios (0.70337-0.70382) that suggests their derivation from a depleted mantle source, with little contamination from the older continental crust. In contrast, the GMGs and MGs have extremely high 87Rb/86Sr and 87Sr/86Sr ratios that reflect the disturbance of the Rb-Sr isotopic system and may give an indication for magmatic-fluid interaction. However, all the granitoids display positive εNd(t) (4.41-6.57) and depleted mantle model ages TDM2 between 777 and 956 Ma, which indicate their derivation from a Neoproterozoic juvenile magma sources and preclude the occurrence of pre-Neoproterozoic crustal rocks in the ANS. The microgranular enclaves represent globules of hot mafic

  8. The strontium isotopic composition of seawater, and seawater-oceanic crust interaction

    International Nuclear Information System (INIS)

    Spooner, E.T.C.

    1976-01-01

    The 87 Sr/ 86 Sr ratio of seawater strontium (0.7091) is less than the 87 Sr/ 86 Sr ratio of dissolved strontium delivered to the oceans by continental run-off (approximately 0.716). Isotope exchange with strontium isotopically lighter oceanic crust during hydrothermal convection within spreading oceanic ridges can explain this observation. In quantitative terms, the current 87 Sr/ 86 Sr ratio of seawater (0.7091) may be maintained by balancing the continental run-off flux of strontium (0.59 x 10 12 g/yr) against a hydrothermal recirculation flux of 3.6 x 10 12 g/yr, during which the 87 Sr/ 86 Sr ratio of seawater drops by 0.0011. A concomitant mean increase in the 87 Sr/ 86 Sr ratio of the upper 4.5 km of oceanic crust of 0.0010 (0.7029-0.7039) should be produced. This required 87 Sr enrichment has been observed in hydrothermally metamorphosed ophiolitic rocks from the Troodos Massif, Cyprus. The post-Upper Cretaceous increase in the strontium isotopic composition of seawater (approximately 0.7075-0.7091) covaries smoothly with inferred increase in land area. This suggests that during this period the main factor which has caused variability in the 87 Sr/ 86 Sr ratio of seawater strontium could have been variation in the magnitude of the continental run-off flux caused by variation in land area. Variations in land area may themselves have been partly a consequence of variations in global mean sea-floor spreading rate. (Auth.)

  9. Boninite petrogenesis: Chemical and Nd-Sr isotopic constraints

    International Nuclear Information System (INIS)

    Cameron, W.E.; Walker, D.A.; McCulloch, M.T.

    1983-01-01

    Major and trace element abundances and Nd and Sr isotopic compositions have been determined for boninites from the Bonin Islands, Cape Vogel (Papua New Guinea) and New Caledonia and for similar lavas from Cyprus and New Zealand. SiO 2 , CaO, incompatible element abundances and epsilonsub(Nd) values are shown to vary systematically with the degree of light rare earth element (LREE) enrichment. Lasub(N)/Ybsub(N) varies from 5.4 to 0.3. The range of epsilonsub(Nd) values is from +8.0 to +1.9. These features are interpreted in terms of mixing of two components: a LREE-depleted magma, derived by partial melting of an already-depleted peridotite source, and a hydrous. LREE-enriched fluid. If La for the fluid is taken as 100 x chondrites, REE abundances observed in boninites can be reproduced by 1-15% addition of the LREE-enriched component. Using a LREE-depleted component inferred from the Cyprus samples (Lasub(N)/Ybsub(N)=0.10), the LREE-enriched component for Tertiary boninites has been calculated to have a Lasub(N)/Ybsub(N) approx.= 20. The LREE-depleted component contains most of the CaO, Sc, HREE and TiO 2 , and has an epsilonsub(Nd) of >= +8. The enriched component contains H 2 O and most of the Zr, Nb and LREE, and has an epsilonsub(Nd) ranging from +6 to at least -5. Origins for the LREE-enriched fluid include derivation from mantle sources similar to those proposed for ocean islands or, more likely, from subducted oceanic or continental crust in island-arc settings. (orig.)

  10. Uncertainty and Detection Limit in Determination of 89,90Sr by Cherenkov Counting

    International Nuclear Information System (INIS)

    Grahek, Z.; Karanovic, G.; Nodilo, M.

    2013-01-01

    The methodology for the rapid determination of 89,90Sr in normal and emergency situations is given. Methodology is based on simultaneous separation of strontium and yttrium from samples and quantitative 89,90Sr determination by Cherenkov counting within three days. Methodology for quantitative determination by Cherenkov counting based on following changes of sample activity during the time is described and discussed. It has been shown that 89,90Sr can be determined with acceptable accuracy when 89Sr/90Sr ratio is over 10:1. Obtained results show that by using low level liquid scintillation counter it can be possible to determine 89Sr and 90Sr in broad range of concentration activities (1 - 1000 Bq (kgL) -1 ) with uncertainties below 10% within 2-3 days. Results also show that accuracy of determination of 89Sr (and 90Sr) depends on determination of difference between separation and counting time when activity ratio of 89Sr/90Sr is high. Analysis of combined uncertainty shows that it mainly depends on uncertainty of efficiency and recovery determination, uncertainty of activities determination for both isotopes and level of background radiation. Portion of each in combined uncertainty depend on level of activity of each isotope and its activity ratio.(author)

  11. A summary of Rb-Sr isotope studies in the Archean Hopedale Block and the adjacent proterozoic Makkovik subprovince, Labrador

    International Nuclear Information System (INIS)

    Grant, N.K.; Hickman, M.H.; Marzano, M.S.; Ermanovics, I.F.

    1983-01-01

    Rb-Sr isotope study of thirteen whole-rock suites of Archean and Proterozoic rocks from Hopedale block and Makkovik Subprovince shows that the crustal history began about 3115 Ma ago. We tentatively recognize younger crustal segments that formed 2920 Ma ago, from which Kanairktok intrusives were derived at 2832 +- 178 Ma. In Makkovik Subprovince the Island Harbour granites range in age from 1843 +- 90 to 1794 +- 71 Ma. These ages overlap with the 1847 +-87 Ma age for Kanairktok shear zone mylonites. The Island Harbour granodiorites from inland localities to the southwest are contaminated with Archean rocks in Makkovik Subprovince and their initial 87 Sr/ 86 ratios imply a crustal contribution to their source. In contrast, the Island Harbour granites of Striped Island were derived from a mantle source. The sills of Striped Island are 1635 +- 47 Ma old. An undeformed northeast trending Kikkertavak dolerite dyke from Hopedale block is 1206 +- 120 Ma

  12. 87Sr/86Sr ratios in hydrothermal waters and deposits from the east pacific rise at 210N

    International Nuclear Information System (INIS)

    Albarede, F.; Michard, A.; Minster, J.F.; Michard, G.

    1981-01-01

    87 Sr/ 86 Sr ratios of three hydrothermal waters collected on the East Pacific Rise at 21 0 N define a mixing line between seawater and a hydrothermal end-member at 0.7030 which is derived by seawater-basalt interaction at ca. 350 0 C and water/rock ratio of about 1.5. Sr concentrations are not affected in the process while Mg uptake from seawater is almost complete. Up to 2/3 of this hydrothermal component is involved in anhydrite precipitation while the Sr isotopic ratio in sulfides (chalcopyrite + sphalerite) cannot be distinguished from that of sulfate. It is estimated that ca. 1 x 10 10 moles of strontium are yearly cycled in the hydrothermal systems of mid-oceanic ridges, thereby affecting the 87 Sr/ 86 Sr budget of seawater. Mass balance between river runoff, limestone precipitation and ridge basalt alteration suggests that the 87 Sr/ 86 Sr ratios of the river runoff are in the range 0.7097-0.7113, and are largely dominated by limestone alteration. (orig.)

  13. On kinetics of 90Sr exchange between Elodea and water surroundings

    International Nuclear Information System (INIS)

    Chebotina, N.Ya.; Yagov, A.P.

    1979-01-01

    The extraction of 90 Sr from elodea was studied in dependence on the of plant preexposition in isotope-bearing water. Elodea plants were submerged in 90 SrCl 2 solution with the concentration of 20 μCi/l for different periods of time (5 and 30 min; 1,5,10,50,100 and 400 h.); after that they were transfered into pure lake water which at first was changed every minute and then in 2,4,8,20,46,72 and 120 hours. Determined was the isotope content in disorbiny solution, and residual plant radioactivity. Radiometry of preparations was carried out 12-14 days after sampling by PST-100 device with BFL-T-25 counter. Periods of biological half-life of 90 Sr(Tsub(1/2) were determined graphically. It was shown that the retention durability of the isotope in plants increased with plant exposure time in Sr-bearing water. It was determined both by total quantity of radionuclide migrated from elodea into water media and forms of its retention in plants. At small plant expositions in radioactive solutions (from 5 min to 5 h) 90% of 90 Sr migrated during the experiment from elodea into water media, but at 400 hour exposition, only 56%. Two forms of radiostrontium bound with biosubstrate with different degree of retention durability were separated

  14. A method for combined Sr-Nd-Hf isotopic analysis of <10 mg dust samples: implication for ice core science

    Science.gov (United States)

    Ujvari, Gabor; Wegner, Wencke; Klötzli, Urs

    2017-04-01

    Aeolian mineral dust particles below the size of 10-20 μm often experience longer distance transport in the atmosphere, and thus Aeolian dust is considered an important tracer of large-scale atmospheric circulation. Since ice core dust is purely Aeolian in origin, discrimination of its potential source region(s) can contribute to a better understanding of past dust activity and climatic/environmental causes. Furthermore, ice core dust source information provides critical experimental constraints for model simulations of past atmospheric circulation patterns [1,2]. However, to identify dust sources in past dust archives such as ice cores, the mineralogy and geochemistry of the wind-blown dust material must be characterized. While the amount of dust in marine cores or common terrestrial archives is sufficient for different types of analyses and even for multiple repeat measurements, dust content in ice cores is usually extremely low even for the peak dusty periods such as the Last Glacial Maximum (LGM) (5-8 mg dust/kg ice; [3]). Since the most powerful dust fingerprinting methods, such as REE composition and Sr-Nd-Pb isotopic analyses are destructive there is a clear need to establish sequential separation techniques of Sr, Nd, Pb and other REEs to get the most information out of small (5-10 mg) dust samples recovered from ice cores. Although Hf isotopes have recently been added as a robust tool of aerosol/dust source discrimination (e.g. [4,5,6,7]), precise Hf isotopic measurements of small (reliable 176Hf/177Hf (and also 87Sr/86Sr, 143Nd/144Nd) ratios. Along with the standards 50, 10 and 5 mg aliquots of the fine (affected by acid treatment and these signatures are extremely stable both within run (0.000008 variability for the three aliquots, i.e. 0.15 ɛNd unit) and between runs of different laboratories (0.00006, ca 1 ɛNd unit). Hf isotopic compositions varied within 1 (NUS) and 5 ɛHf units (BEI) between the three aliquots, but the BEI sample always gave more

  15. Beta strength distributions in neutron-deficient Kr and Sr isotopes using a total absorption spectrometer

    CERN Document Server

    Maréchal, F

    2003-01-01

    Far from the line of stability, beta -decay studies are often a primary source of information on nuclear structure. The measured beta -strength distribution for a given decay can be used to verify the accuracy of our theoretical description of the parent nucleus ground state and the states populated in the daughter nucleus. Total absorption spectrometers based on large NaI crystals are well suited tools to determine the beta -strength distribution over the whole Q /sub EC/ decay window. The newly built spectrometer TAgS, dedicated to such studies, is presented and its performances and possibilities are discussed in the light of experiments performed at the ISOLDE /CERN mass separator. The resulting information on ground state deformations for the /sup 74/Kr and /sup 76/Sr isotopes are discussed. (22 refs).

  16. 87Sr enrichment of ophiolitic sulphide deposits in Cyprus confirms ore formation by circulating seawater

    International Nuclear Information System (INIS)

    Chapman, H.J.; Spooner, E.T.C.

    1977-01-01

    The hypothesis that seawater was the source of the hydrothermal fluid which formed the Upper Cretaceous ophiolitic cupriferous pyrite ore deposits of the Troodos Massif (Cyprus) has been tested by analysing the strontium isotopic composition of thirteen mineralized samples from four mines. Initial 87 Sr/ 86 Sr ratios range from 0.7052+-0.0001 to 0.7075+-0.00002, the latter value being indistinguishable from that of Upper Cretaceous seawater at 0.7076+-0.0006 (2 sigma). Hence, the mineralized metabasalt samples have been contaminated with 87 Sr, relative to initial magmatic strontium isotope ratios of the Troodos ophiolitic complex (0.70338+-0.00010 to 0.70365+-0.00005). Since seawater was the only source of strontium available during formation of the Troodos Complex which was isotopically relatively enriched in 87 Sr, the data confirm that seawater was the source of the hydrothermal oreforming fluid. (Auth.)

  17. Using noble gases and 87Sr/86Sr to constrain heat sources and fluid evolution at the Los Azufres Geothermal Field, Mexico

    Science.gov (United States)

    Wen, T.; Pinti, D. L.; Castro, M. C.; Lopez Hernandez, A.; Hall, C. M.; Shouakar-Stash, O.; Sandoval-Medina, F.

    2017-12-01

    Geothermal wells and hot springs were sampled for noble gases' volume fraction and isotopic measurements and 87Sr/86Sr in the Los Azufres Geothermal Field (LAGF), Mexico, to understand the evolution of fluid circulation following three decades of exploitation and re-injection of used brines. The LAGF, divided into the Southern Production Zone (SPZ) and the Northern Production Zone (NPZ), is hosted in a Miocene to Pliocene andesitic volcanic complex covered by Quaternary rhyolitic-dacitic units. Air contamination corrected 3He/4He ratios (Rc) normalized to the atmospheric ratio (Ra=1.384 x 10-6), show a median value of 6.58 indicating a dominant mantle helium component. Contributions of crustal helium up to 53% and 18% are observed in NPZ and SPZ, respectively. Observations based on Rc/Ra and 87Sr/86Sr ratios points to the mixing of three magmatic sources supplying mantle helium to the LAGF: (1) a pure mantle He (Rc/Ra = 8) and Sr (87Sr/86Sr = 0.7035) source; (2) a pure mantle helium (Rc/Ra = 8) with some radiogenic Sr (87Sr/86Sr = 0.7049) source possibly resulting from Quaternary rhyolitic volcanism; and (3) a fossil mantle He component (Rc/Ra = 3.8) with some radiogenic Sr (87Sr/86Sr = 0.7038), corresponding possibly to the Miocene andesite reservoir. Intrusions within the last 50 kyrs from sources (1) and (2) are likely responsible for the addition of mantle volatiles and heat to the hydrothermal system of Los Azufres. He and Ar isotopes indicate that heat flow is transported by both convection and conduction. Atmospheric noble gas elemental ratios suggest that geothermal wells located closer to the western re-injection zone are beginning to be dominated by re-injection of used brines (injectate). The area affected by boiling in LAGF has further extended to the north and west since the last noble gas sampling campaign in 2009.

  18. 87Sr/86Sr sourcing of ponderosa pine used in Anasazi great house construction at Chaco Canyon, New Mexico

    Science.gov (United States)

    Reynolds, Amanda C.; Betancourt, Julio L.; Quade, Jay; Patchett, P. Jonathan; Dean, Jeffery S.; Stein, John

    2005-01-01

    Previous analysis of 87Sr/86Sr ratios shows that 10th through 12th century Chaco Canyon was provisioned with plant materials that came from more than 75 km away. This includes (1) corn (Zea mays) grown on the eastern flanks of the Chuska Mountains and floodplain of the San Juan River to the west and north, and (2) spruce (Picea sp.) and fir (Abies sp.) beams from the crest of the Chuska and San Mateo Mountains to the west and south. Here, we extend 87Sr/86Sr analysis to ponderosa pine (Pinus ponderosa) prevalent in the architectural timber at three of the Chacoan great houses (Pueblo Bonito, Chetro Ketl, Pueblo del Arroyo). Like the architectural spruce and fir, much of the ponderosa matches the 87Sr/86Sr ratios of living trees in the Chuska Mountains. Many of the architectural ponderosa, however, have similar ratios to living trees in the La Plata and San Juan Mountains to the north and Lobo Mesa/Hosta Butte to the south. There are no systematic patterns in spruce/fir or ponderosa provenance by great house or time, suggesting the use of stockpiles from a few preferred sources. The multiple and distant sources for food and timber, now based on hundreds of isotopic values from modern and archeological samples, confirm conventional wisdom about the geographic scope of the larger Chacoan system. The complexity of this procurement warns against simple generalizations based on just one species, a single class of botanical artifact, or a few isotopic values.

  19. pH-Dependent isotope exchange and hydrogenation catalysed by water-soluble NiRu complexes as functional models for [NiFe]hydrogenases.

    Science.gov (United States)

    Kure, Bunsho; Matsumoto, Takahiro; Ichikawa, Koji; Fukuzumi, Shunichi; Higuchi, Yoshiki; Yagi, Tatsuhiko; Ogo, Seiji

    2008-09-21

    The pH-dependent hydrogen isotope exchange reaction between gaseous isotopes and medium isotopes and hydrogenation of the carbonyl compounds have been investigated with water-soluble bis(mu-thiolate)(mu-hydride)NiRu complexes, Ni(II)(mu-SR)(2)(mu-H)Ru(II) {(mu-SR)(2) = N,N'-dimethyl-N,N'-bis(2-mercaptoethyl)-1,3-propanediamine}, as functional models for [NiFe]hydrogenases. In acidic media (at pH 4-6), the mu-H ligand of the Ni(II)(mu-SR)(2)(mu-H)Ru(II) complexes has H(+) properties, and the complexes catalyse the hydrogen isotope exchange reaction between gaseous isotopes and medium isotopes. A mechanism of the hydrogen isotope exchange reaction between gaseous isotopes and medium isotopes through a low-valent Ni(I)(mu-SR)(2)Ru(I) complex is proposed. In contrast, in neutral-basic media (at pH 7-10), the mu-H ligand of the Ni(II)(mu-SR)(2)(mu-H)Ru(II) complexes acts as H(-), and the complexes catalyse the hydrogenation of carbonyl compounds.

  20. Geographic variation of strontium and hydrogen isotopes in avian tissue: implications for tracking migration and dispersal.

    Directory of Open Access Journals (Sweden)

    Megan J Sellick

    Full Text Available 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.Here, we describe variation in both stable-hydrogen (deltaD(F and strontium ((87Sr/(86Sr(F 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 deltaD(F was correlated with latitude of the sampling site, whereas (87Sr/(86Sr(F was correlated with longitude. deltaD(F was related to deltaD of meteoric waters where molting occurred and (87Sr/(86Sr(F 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 deltaD or (87Sr/(86Sr alone to 74% using both isotopes.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.

  1. Dating and source determination of volcanic rocks from Khunik area (South of Birjand, South Khorasan using Rb-Sr and Sm-Nd isotopes

    Directory of Open Access Journals (Sweden)

    Somayeh Samiee

    2016-12-01

    Full Text Available The Khunik area is located in the south of Birjand, Khorasan province, in the eastern margin of Lut block. Tertiary volcanic rocks have andesite to trachy-andesite composition. Dating analyzing by Rb-Sr method on plagioclase and hornblende as well as whole-rock isochron method was performed on pyroxene-hornblende andesite rock unit. On this basis the emplacement age is Upper Paleocene (58±11 Ma. These rocks have initial 87Sr/86Sr and εNd 0.7046-0.7049 and 2.16-3.12, respectively. According to isotopic data, volcanic rocks originated from depleted mantle and have the least crust contamination while it was fractionated. Geochemically, Khunik volcanic rocks have features typical of calk-alkaline to shoshonite and are metaluminous. Enrichment in LILEs and typical negative anomalies of Nb and Ti are evidences that the volcanic rocks formed in a subduction zone and active continental margin. Modeling suggests that these rocks were derived dominantly from 1–5% partial melting of a mainly spinel garnet lherzolite mantle source that is metasomatized by slab-derived fluid.

  2. Isotopic composition of Pb and Th in interplinian volcanics from Somma-Vesuvius volcano, Italy

    International Nuclear Information System (INIS)

    Cortini, M.; De Vivo, B.; Somma, R.; Ayuso, R.A.; Holden, P.

    2004-01-01

    We present a detailed isotopic study of volcanic rocks emitted from Somma-Vesuvius volcano during three periods of interplinian activity: 'Protohistoric' (3550 y B.P. to 79 A.D.), 'Ancient Historic' (79 to 472 A.D.) and 'Medieval' (472 to 1631 A.D.). Pb isotopic compositions of two acid leached fractions and whole rock residues of 37 whole rock samples (determined by Somma et al., 2001) show that each of the three interplinian periods is distinguished by small, systematic, and unique uranogenic and thorogenic Pb isotopic trends. This key and novel feature is compatible with the notion that the Pb isotopic data reflect small-scale source heterogeneity operating over relatively short periods of time. From this representative group of samples, a selected set of nine whole rocks were analyzed for Th isotopes. 232 Th/ 238 U ratios in the source can be obtained independently from Pb and from Th isotopes. Those obtained from Pb isotopes represent source ratios, time-integrated over the whole age of the earth; they range from 3.9 to 4.1. 232 Th/ 238 U obtained from Th isotopes are those of the present source. They are lower, and cluster around 3.5; this difference probably indicates recent U enrichment of the present source. The behavior of Pb, as inferred by its isotopic ratios, is quite distinct from that of Sr and Nd isotopes: Pb isotope variations are not correlated to Sr or Nd isotope variations. The isotopic contrast is compatible with the idea that the isotopes were decoupled during magmatic production, evolution, and ascent through the crust. Thus, the Pb isotopes do not reflect the effects of the same processes as in the case of the Sr and Nd isotopes, or, as we also favor, they do not necessarily reflect the same source contributions into the magmas. Moreover, the Pb isotopic evolution of the interplinian rocks chiefly reflects mixing, driven by processes that are superimposed on, and independent of, other source contributions that determine the isotopic

  3. Stable isotope analysis of Dacryoconarid carbonate microfossils: a new tool for Devonian oxygen and carbon isotope stratigraphy.

    Science.gov (United States)

    Frappier, Amy Benoit; Lindemann, Richard H; Frappier, Brian R

    2015-04-30

    warrant further exploration of dacryoconarid stable isotope proxy sensitivity, the isotopic contrast among dacryoconarids, other taxa, and bulk rock, as well as other potential dacryoconarid proxies (Mg/Ca, Sr/Ca, (87) Sr/(86) Sr, microlaser and ion microprobe isotope techniques, and clumped isotopes) for stratigraphic research. Copyright © 2015 John Wiley & Sons, Ltd.

  4. Pb-Sr isotopic and geochemical constraints on sources and processes of lead contamination in well waters and soil from former fruit orchards, Pennsylvania, USA: A legacy of anthropogenic activities

    Science.gov (United States)

    Ayuso, Robert A.; Foley, Nora K.

    2016-01-01

    Isotopic discrimination can be an effective tool in establishing a direct link between sources of Pb contamination and the presence of anomalously high concentrations of Pb in waters, soils, and organisms. Residential wells supplying water containing up to 1600 ppb Pb to houses built on the former Mohr orchards commercial site, near Allentown, PA, were evaluated to discern anthropogenic from geogenic sources. Pb (n = 144) and Sr (n = 40) isotopic data and REE (n = 29) data were determined for waters from residential wells, test wells (drilled for this study), and surface waters from pond and creeks. Local soils, sediments, bedrock, Zn-Pb mineralization and coal were also analyzed (n = 94), together with locally used Pb-As pesticide (n = 5). Waters from residential and test wells show overlapping values of 206Pb/207Pb, 208Pb/207Pb and 87Sr/86Sr. Larger negative Ce anomalies (Ce/Ce*) distinguish residential wells from test wells. Results show that residential and test well waters, sediments from residential water filters in water tanks, and surface waters display broad linear trends in Pb isotope plots. Pb isotope data for soils, bedrock, and pesticides have contrasting ranges and overlapping trends. Contributions of Pb from soils to residential well waters are limited and implicated primarily in wells having shallow water-bearing zones and carrying high sediment contents. Pb isotope data for residential wells, test wells, and surface waters show substantial overlap with Pb data reflecting anthropogenic actions (e.g., burning fossil fuels, industrial and urban processing activities). Limited contributions of Pb from bedrock, soils, and pesticides are evident. High Pb concentrations in the residential waters are likely related to sediment build up in residential water tanks. Redox reactions, triggered by influx of groundwater via wells into the residential water systems and leading to subtle changes in pH, are implicated in precipitation of Fe oxyhydroxides

  5. Isotopes as Tracers of the Hawaiian Coffee-Producing Regions

    Science.gov (United States)

    2011-01-01

    Green coffee bean isotopes have been used to trace the effects of different climatic and geological characteristics associated with the Hawaii islands. Isotope ratio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry ((MC)-ICP-SFMS and ICP-QMS) were applied to determine the isotopic composition of carbon (δ13C), nitrogen (δ15N), sulfur (δ34S), and oxygen (δ18O), the isotope abundance of strontium (87Sr/86Sr), and the concentrations of 30 different elements in 47 green coffees. The coffees were produced in five Hawaii regions: Hawaii, Kauai, Maui, Molokai, and Oahu. Results indicate that coffee plant seed isotopes reflect interactions between the coffee plant and the local environment. Accordingly, the obtained analytical fingerprinting could be used to discriminate between the different Hawaii regions studied. PMID:21838232

  6. Strontium isotope ratios - a possible tool to study the authenticity of Indian tea using MC-ICP-MS

    International Nuclear Information System (INIS)

    Lagad, Rupali A.; Alamelu, D.; Aggarwal, Suresh K.; Singh, Sunil K.

    2011-01-01

    In the present study, an analytical procedure based on determination of the Sr isotope ratio 87 Sr/ 86 Sr in the Indian tea samples by MC-ICP-MS was developed and applied to 28 tea samples from four different Indian regions. The 87 Sr/ 86 Sr isotope ratio of the tea samples in different Indian regions is strongly dependent on the soil and growth environment condition. The analysis results of 28 Indian tea samples revealed that 87 Sr/ 86 Sr atom ratio follows the order Darjeeling > Kangra > Assam > Munnar

  7. Rb-Sr age of a basic dyke, Schirmacher oasis, east Antarctica

    International Nuclear Information System (INIS)

    Dayal, A.M.; Hussain, S.M.

    1996-01-01

    In order to understand the crustal evolution in east Antartica, detailed geological, geochemical and isotopic studies of the various rocks in the area are necessary. This paper reports the Rb-Sr isotopic data on a gabbroic dyke in the Schirmacher oasis

  8. New neutron capture and total cross section measurements on 88Sr and their impact on s-process nucleosynthesis

    International Nuclear Information System (INIS)

    Koehler, P.E.; Spencer, R.R.; Guber, K.H.

    1998-01-01

    The authors have made new and improved measurements of the neutron capture and total cross sections of 88 Sr at the Oak Ridge Electron Linear Accelerator (ORELA). Improvements over previous measurements include a wider incident neutron energy range, the use of metallic rather than carbonate samples, better background subtraction, reduced sensitivity to sample-dependent backgrounds, and better pulse-height weighting functions. Because of its small cross section, the 88 Sr(n,γ) reaction is an important bottleneck during the s-process nucleosynthesis. Hence, an accurate determination of this rate is needed to better constrain the neutron exposure in s-process models and to more fully exploit the recently discovered isotopic anomalies in certain meteorites. They describe the experimental procedures, compare the results to previous data, and discuss their astrophysical impact

  9. Contamination in mafic mineral-rich calc-alkaline granites: a geochemical and Sr-Nd isotope study of the Neoproterozoic Piedade Granite, SE Brazil

    Directory of Open Access Journals (Sweden)

    Leite Renato J.

    2006-01-01

    Full Text Available The Piedade Granite (~600 Ma was emplaced shortly after the main phase of granite magmatism in the Agudos Grandes batholith, Apiaí-Guaxupé Terrane, SE Brazil. Its main units are: mafic mineral-rich porphyritic granites forming the border (peraluminous muscovite-biotite granodiorite-monzogranite MBmg unit and core (metaluminous titanite-bearing biotite monzogranite BmgT unit and felsic pink inequigranular granite (Bmg unit between them. Bmg has high LaN/YbN (up to 100, Th/U (>10 and low Rb, Nb and Ta, and can be a crustal melt derived from deep-seated sources with residual garnet and biotite. The core BmgT unit derived from oxidized magmas with high Mg# (~45, Ba and Sr, fractionated REE patterns (LaN/YbN= 45, 87Sr/86Sr(t~ 0.710, epsilonNd(t ~ -12 to -14, interpreted as being high-K calc-alkaline magmas contaminated with metasedimentary rocks that had upper-crust signature (high U, Cs, Ta. The mafic-rich peraluminous granites show a more evolved isotope signature (87Sr/86Sr(t = 0.713-0.714; epsilonNd(t= -14 to -16, similar to Bmg, and Mg# and incompatible trace-element concentrations intermediate between Bmg and BmgT. A model is presented in whichMBmgis envisaged as the product of contamination between a mafic mineral-rich magma consanguineous with BmgT and pure crustal melts akin to Bmg.

  10. Accurate hydrocarbon estimates attained with radioactive isotope

    International Nuclear Information System (INIS)

    Hubbard, G.

    1983-01-01

    To make accurate economic evaluations of new discoveries, an oil company needs to know how much gas and oil a reservoir contains. The porous rocks of these reservoirs are not completely filled with gas or oil, but contain a mixture of gas, oil and water. It is extremely important to know what volume percentage of this water--called connate water--is contained in the reservoir rock. The percentage of connate water can be calculated from electrical resistivity measurements made downhole. The accuracy of this method can be improved if a pure sample of connate water can be analyzed or if the chemistry of the water can be determined by conventional logging methods. Because of the similarity of the mud filtrate--the water in a water-based drilling fluid--and the connate water, this is not always possible. If the oil company cannot distinguish between connate water and mud filtrate, its oil-in-place calculations could be incorrect by ten percent or more. It is clear that unless an oil company can be sure that a sample of connate water is pure, or at the very least knows exactly how much mud filtrate it contains, its assessment of the reservoir's water content--and consequently its oil or gas content--will be distorted. The oil companies have opted for the Repeat Formation Tester (RFT) method. Label the drilling fluid with small doses of tritium--a radioactive isotope of hydrogen--and it will be easy to detect and quantify in the sample

  11. The use of Rb-Sr and K-Ar dating methods as a stratigraphic tool applied to sedimentary rocks and minerals

    International Nuclear Information System (INIS)

    Bonhomme, M.G.

    1982-01-01

    Rb-Sr and K-Ar methods can be used for direct numerical chronostratigraphy of sediments using the clay silicates they contain. The interpretation of the ages calculated depends on the satisfaction of the following requirements: (1) The series studied must include diagenetic clay sediments. Coarsely-detrital or slightly-metamorphic formations must be excluded. Studies in progress concerning decarbonatation may lead to the application of direct dating of sediments being extended to carbonate sediments. (2) Careful mineralogical study of the clay minerals must prove early diagenetic recrystallization or new formation. This part of the study must precede any isotopic work. (3) The isotopic study must involve the use of both Rb-Sr and K-Ar methods. The extreme sensibility of the K-Ar isotopic system to late diagenesis helps to choose between early or late diagenesis: a younger K-Ar age may generally be regarded as that of the late diagenesis, whereas the Rb-Sr age may be that of the early diagenesis. (4) The initial 87 Sr/ 86 Sr isotopic ratio is not always a reliable criterion, owing to the effects of the dilution of the radiogenic 87 Sr by the great amounts of primary Sr contained in carbonates. (5) The regularly-decreasing succession of isotopic ages must follow the stratigraphic succession. When this condition is satisfied, there is a high probability that the calculated ages are indeed those of the deposition dates. (Auth.)

  12. Accurate determination and certification of bromine in plastic by isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Ohata, Masaki; Miura, Tsutomu

    2014-01-01

    Highlights: • Accurate analytical method of Br in plastic was studied by isotope dilution ICPMS. • A microwave acid digestion using quartz vessel was suitable for Br analysis. • Sample dilution by NH 3 solution could remove memory effect for ICPMS measurement. • The analytical result of the ID-ICPMS showed consistency with that of INAA. • The ID-ICPMS developed could apply to certification of Br in candidate plastic CRM. - Abstract: The accurate analytical method of bromine (Br) in plastic was developed by an isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The figures of merit of microwave acid digestion procedures using polytetrafluoroethylene (PTFE) or quartz vessels were studied and the latter one was suitable for Br analysis since its material was free from Br contamination. The sample dilution procedures using Milli-Q water or ammonium (NH 3 ) solution were also studied to remove memory effect for ICPMS measurement. Although severe memory effect was observed on Milli-Q water dilution, NH 3 solution could remove it successfully. The accuracy of the ID-ICPMS was validated by a certified reference material (CRM) as well as the comparison with the analytical result obtained by an instrumental neutron activation analysis (INAA) as different analytical method. From these results, the ID-ICPMS developed in the present study could be evaluated as accurate analytical method of Br in plastic materials and it could apply to certification of Br in candidate plastic CRM with respect to such regulations related to RoHS (restriction of the use of hazardous substances in electrical and electronics equipment) directive

  13. SU-F-I-56: High-Precision Gamma-Ray Analysis of Medical Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, N; Chillery, T; Chowdhury, P; Lister, C [University of Massachusetts-Lowell, Lowell, MA (United States); McCutchan, E [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY (United States); Smith, C [BLIP Facility, Brookhaven National Laboratory, Upton, NY (United States)

    2016-06-15

    Purpose: Advanced, time-resolved, Compton-suppressed gamma-ray spectroscopy with germanium detectors is implemented for assaying medical isotopes to study the radioactive decay process leading to a more accurate appraisal of the received dose and treatment planning. Lowell’s Array for Radiological Assay (LARA), a detector array that is comprised of six Compton-suppressed high-purity germanium detectors, is currently under development at UMass-Lowell which combines Compton-suppression and time-and-angle correlations to allow for highly efficient and highly sensitive measurements. Methods: Two isotopes produced Brookhaven Linac Isotope Producer (BLIP) were investigated. {sup 82}Sr which is the parent isotope for producing {sup 82}Rb is often used in cardiac PET. {sup 82}Sr gamma-ray spectrum is dominated by the 511keV photons from positron annihilation which prevent precise measurement of co-produced contaminant isotopes. A second project was to investigate the production of platinum isotopes. Natural platinum was bombarded with protons from 53MeV to 200MeV. The resulting spectrum was complicated due to the large number of stable platinum isotopes in the target, the variety of open reaction channels (p,xn), (p,pxn), (p,axn). Results: By using face-to-face NaI(Tl) counters 90-degrees to the Compton-suppressed germaniums to detect the 511keV photons, a much cleaner and more sensitive measurement of {sup 85}Sr and other contaminants was obtained. For the platinum target, we identified the production of {sup 188–189–191–195}Pt, {sup 191–192–193–194–195–196}Au and {sup 186–188–189–190–192–194–189–190–192–194}Ir. For example, at the lower energies (53 and 65MeV), we measured {sup 191}Pt production cross-sections of 144mb and 157mb. Considerable care was needed in following the process of dissolving and diluting the samples to get consistent results. The new LARA array will help us better ascertain the absolute efficiency of the counting

  14. 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:

    Science.gov (United States)

    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.

  15. Fast and sensitive determination of Sr-90 and SR-89 activity in milk by ion-chromatography and liquid scintillation

    International Nuclear Information System (INIS)

    Figueiredo, V.; Herrmann, A.

    1992-01-01

    A method for fast and exact determination of both strontium isotopes in milk and other foodstuffs, combination high performance ion chromatographic separation with by liquid scintillation counting, which enables the desired results to be obtained with very satisfactory precision and reproducibility within 24 hours, has been developed. The lowest detectable activity lies by 3 Bq/liter for Sr-90 and 1 Bq/liter for Sr-89 which is satisfactory for assessing a situation in a time crisis. (author)

  16. Electromagnetic transition strengths in 75Kr and 79Sr

    International Nuclear Information System (INIS)

    Cardona, M.A.; Filevich, Alberto; Garcia Bermudez, Gerardo; Achterberg, Erhard

    1989-01-01

    Experimental and theoretical studies of nuclear structure in light Kr and Sr isotopes have revealed a region of large quadrupole deformation. In this work, deformation properties of odd-nuclei 75 Kr and 79 Sr have been investigated. For this purpose, lifetime of excited states in both nuclei have been measured by means of the recoil distance Doppler shift technique. These nuclei were populated via the reactions: 54 Fe( 24 Mg,2pn) 75 Kr at 75 MeV and 54 Fe( 28 Si,2pn) 79 Sr at 97 MeV, the beams were provided by the Tandar accelerator. The experimental B(E2) values for these nuclei were well reproduced in the framework of the triaxial-rotor-plus quasiparticle model. In order to fix the parameters of the model a study of neighboring even-even Kr isotopes was performed. The whole N=3 and N=4 oscillator shell was used for the space configuration of the odd particle for negative and positive bands respectively. (Author) [es

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

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Andrew J. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Capo, Rosemary C. [Univ. of Pittsburgh, PA (United States); Stewart, Brian W. [Univ. of Pittsburgh, PA (United States); Phan, Thai T. [Univ. of Pittsburgh, PA (United States); Jain, Jinesh C. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Hakala, Alexandra [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Guthrie, George D. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hakala, Jacqueline Alexandra [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    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.

  19. Final Progress Report: Isotope Identification Algorithm for Rapid and Accurate Determination of Radioisotopes Feasibility Study

    International Nuclear Information System (INIS)

    Rawool-Sullivan, Mohini; Bounds, John Alan; Brumby, Steven P.; Prasad, Lakshman; Sullivan, John P.

    2012-01-01

    This is the final report of the project titled, 'Isotope Identification Algorithm for Rapid and Accurate Determination of Radioisotopes,' PMIS project number LA10-HUMANID-PD03. The goal of the work was to demonstrate principles of emulating a human analysis approach towards the data collected using radiation isotope identification devices (RIIDs). It summarizes work performed over the FY10 time period. The goal of the work was to demonstrate principles of emulating a human analysis approach towards the data collected using radiation isotope identification devices (RIIDs). Human analysts begin analyzing a spectrum based on features in the spectrum - lines and shapes that are present in a given spectrum. The proposed work was to carry out a feasibility study that will pick out all gamma ray peaks and other features such as Compton edges, bremsstrahlung, presence/absence of shielding and presence of neutrons and escape peaks. Ultimately success of this feasibility study will allow us to collectively explain identified features and form a realistic scenario that produced a given spectrum in the future. We wanted to develop and demonstrate machine learning algorithms that will qualitatively enhance the automated identification capabilities of portable radiological sensors that are currently being used in the field.

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

    Science.gov (United States)

    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

  1. Dating the Indo-Asia collision in NW Himalaya: constraints from Sr-Nd isotopes and detrital zircon (U-Pb) and Hf isotopes of Paleogene-Neogene rocks in the Katawaz basin, NW Pakistan

    Science.gov (United States)

    Zhuang, Guangsheng; Najman, Yani; Millar, Ian; Chauvel, Catherine; Guillot, Stephane; Carter, Andrew

    2015-04-01

    The time of collision between the Indian and Asian plates is key for understanding the convergence history and the impact on climatic systems and marine geochemistry. Despite much active research, the fundamental questions still remain elusive regarding when and where the Indian plate collided with the Asian plate. Especially in the west Himalaya, the questions become more complex due to disputes on the amalgamation history of interoceanic Kohistan-Ladakh arcs (KLA) with Karakoram of the Asian plate and the Indian plate. Here, we present a result of multiple-isotopic geochemistry and geochronology study in the Katawaz Basin in NW Pakistan, a remnant oceanic basin on the western Indian plate which was the repository for the sediments eroded from the west Himalaya ( Qayyum et al., 1996, 1997a, 1997b, 2001; Carter et al., 2010), to evaluate the time and character of collision in this region. In this study, we analyzed 22 bulk mudstone samples for Sr-Nd isotopes and 11 medium-grained sandstones for detrital zircon (U-Pb) geochronology and Hf isotopes. We constructed the Cenozoic chronology in the Katawaz Basin based on our newly collected detrital zircon U-Pb ages and fission track ages. We present the first record of Katawaz chronology that constrained the Khojak Formation to be current study revealed that the Katawaz sedimentary sequence ranges in age from Eocene to the earliest Miocene. The samples from the Nisai Formation show the 87Sr/86Sr - ɛNd values overlapping those of the end member of the Karakoram of Asian origin, revealing the arrival of Asian detritus on the Indian plate prior to 50 Ma. There are two parallel lines of evidence supporting this conclusion: (1) young zircon grains (Journal of the Geological Society 154, 753-756. Qayyum, M., Lawrence, R.D., Niem, A.R., 1997b. Molasse-Delta-flysch continuum of the Himalayan orogeny and closure of the Paleogene Katawaz Remnant Ocean, Pakistan. International geology review 39, 861-875. Qayyum, M., Niem, A

  2. Radiogenic age and isotopic studies

    International Nuclear Information System (INIS)

    Parrish, R.R.

    1990-01-01

    This is one of an annual collection of reports presenting data from the Geochronology Section of the Continental Geoscience Division of the Geological Survey of Canada (GSC). The main purpose of this collection is to make geochronological and other radiogenic isotope data produced by the section available promptly to the geological community. Reports make full presentation of the data, relate these to field settings and make comparatively short interpretations. Other geochronological and isotope data produced in the laboratory but published in outside journals or separate GSC publications are summarized at the end of this report. Reports in this issue cover methods for Rb-Sr and Sm-Nd isotopic analyses; 40 Ar- 39 Ar ages for the New Quebec Crater and for basaltic rocks; U-Pb ages for a differentiated mafic sill in the Ogilvie Mountains, plutonic rocks in the Contwoyto-Nose Lakes are, zircons from the Anton Complex, the Clinton-Colden gabbro-anorthosite intrusion, the Himag plutonic suite, the Campbell granite, the Central Gneiss Belt, Silurian granites, a metarhyolite, plagiogranite and gabbro, and the Wage shear zone; Rb-Sr ages for granitic rocks; K-Ar and Rb-Sr geochronology of granites; a compilation of K-Ar ages; ages of archean and proterozoic mylonites and pre-Misi granitoid domes; and reconnaissance geochronology of Baffin Island

  3. Strontium and neodymium isotopic evidence for the heterogeneous nature and development of the mantle beneath Afar (Ethiopia)

    International Nuclear Information System (INIS)

    Betton, P.J.; Civetta, L.

    1984-01-01

    Neodymium isotope and REE analyses of recent volcanic rocks and spinel lherzolite nodules from the Afar area are reported. The 143 Nd/ 144 Nd ratios of the volcanic rocks range from 0.51286 to 0.51304, similar to the range recorded from Iceland. However, the 87 Sr/ 86 Sr ratios display a distinctly greater range (0.70328-0.70410) than those reported from the primitive rocks of Iceland. Whole rock samples and mineral separates from the spinel lherzolite nodules exhibit uniform 143 Nd/ 144 Nd ratios (ca. 0.5129) but varied 87 Sr/ 86 Sr ratios in the range 0.70427-0.70528. The Sr-Nd isotope variations suggest that the volcanic rocks may have been produced by mixing between two reservoirs with distinct isotopic compositions. Two possible magma reservoirs in this area are the source which produced the 'MORB-type' volcanics in the Red Sea and Gulf of Aden and the anomalous source represented by the nodule suite. The isotopic composition of the volcanics is compatible with mixing between these two reservoirs. It is shown that the anomalous source with a high 87 Sr/ 86 Sr ratio cannot have been produced by simple processes of partial melting and mixing within normal mantle. Instead the high 87 Sr/ 86 Sr is equated with a fluid phase. A primitive cognate fluid, subducted seawater or altered oceanic lithosphere may have been responsible for the generation of the source with a high 87 Sr/ 86 Sr ratio. (orig.)

  4. Sr and Nd isotopic compositions, age and petrogenesis of A-type granitoids of the Vernon Supersuite, New Jersey Highlands, USA

    Science.gov (United States)

    Volkert, R.A.; Feigenson, M.D.; Patino, L.C.; Delaney, J.S.; Drake, Avery A.

    2000-01-01

    Voluminous late Mesoproterozoic monzonite through granite of the Vernon Supersuite underlies an area of approximately 1300 km2 in the Highlands of northern New Jersey. The Vernon Supersuite consists of hastingsite ?? biotite-bearing granitoids of the Byram Intrusive Suite (BIS) and hedenbergite-bearing granitoids of the Lake Hopatcong Intrusive Suite (LHIS). These rocks have similar major and trace element abundances over a range of SiO2 from 58 to 75 wt.%, are metaluminous to weakly peraluminous, and have a distinctive A-type chemistry characterized by high contents of Y, Nb, Zr, LREE, and Ga/Al ratios, and low MgO, CaO, Sr and HREE. Whole-rock Rb-Sr isochrons of BIS granite yield an age of 1116 ?? 41 Ma and initial 87Sr/86Sr ratio of 0.70389, and of LHIS granite an age of 1095 ?? 9 Ma and initial 87Sr/86Sr ratio of 0.70520. Both suites have similar initial 143Nd/144Nd ratios of 0.511267 to 0.511345 (BIS) and 0.511359 to 0.511395 (LHIS). Values of ??(Nd) are moderately high and range from +1.21 to +2.74 in the BIS and +2.24 +2.95 in the LHIS. Petrographic evidence, field relationships, geochemistry, and isotopic data support an interpretation of comagmatism and the derivation of both suites from a mantle-derived or a juvenile lower crustal parent with little crustal assimilation. Both suites crystallized under overlapping conditions controlled by P-T-f(H(2)O). Lake Hopatcong magma crystallized at a liquidus temperature that approached 900??C and a pressure of about 6 kbar, and remained relatively anhydrous throughout its evolution. Initial P-T conditions of the Byram magma were ??? 850??C and about 5.5 kbar. BIS magma was emplaced contemporaneous with, or slightly preceding LHIS magma, and both magmas were emplaced during a compressional tectonic event prior to granulite facies metamorphism that occurred in the Highlands between 1080 and 1030 Ma. (C) 2000 Elsevier Science B.V. All rights reserved.

  5. 90Y and 90Sr separation from hydrochloric acid solutions using TODGA as the extractant by solvent extraction and SLM methods

    International Nuclear Information System (INIS)

    Dutta, S.; Raut, D.R.; Mohapatra, P.K.; Manchanda, V.K.

    2010-01-01

    Yttrium-90 is an important radionuclide known for its therapeutic application in nuclear medicine. It is a pure β-emitter with no associated gamma rays and decays to stable daughter 90 Zr. Suitability of this isotope is because of its short half-life (t 1/2 = 64.2 hrs) and high β emissions (E max = 2.28 MeV. An important source of 90 Y is through the decay of 90 Sr, which produces carrier free isotope. 90 Sr (t 1/2 28 yrs) attains secular equilibrium with 90 Y in a short period and can serve as a long term source for the latter isotope because of relatively long half-life of the parent isotope. Solvent extraction studies with N,N,N',N'-tetra-octyldiglycolamide (TODGA) has shown that Y(III) is well extracted in 6 M HCI while at the same time, extraction of Sr(II) is very low leading to a separation factor (D Y /D Sr = 60,000). This property of TODGA can be exploited for the separation of Y from Sr. In the present work, Supported Liquid Membrane (SLM) based separation of Y and Sr has been explored using TODGA as the carrier

  6. The isotopic and chemical evolution of Mount St. Helens

    International Nuclear Information System (INIS)

    Halliday, A.N.; Fallick, A.E.; Dickin, A.P.; Mackenzie, A.B.; Stephens, W.E.

    1983-01-01

    Isotopic and major and trace element analysis of nine samples of eruptive products spanning the history of the Mt. St. Helens volcano suggest three different episodes; (1) 40,000-2500 years ago: eruptions of dacite with epsilonsub(Nd) = +5, epsilonsub(Sr) = -10, variable delta 18 O, 206 Pb/ 204 Pb approx.= 18.76, Ca/Sr approx.= 60, Rb/Ba- approx.= 0.1, La/Yb approx.= 18, (2) 2500-1000 years ago: eruptions of basalt, andesite and dacite with epsilonsub(Nd) = +4 to + 8, epsilonsub(Sr) = -7 to -22, variable delta 18 O (thought to represent melting of differing mantle-crust reservoirs), 206 Pb/ 204 Pb = 18.81-18.87, variable Ca/Sr, Rb/Ba, La/Yb and high Zr, (3) 1000 years ago to present day: eruptions of andesite and dacite with epsilonsub(Nd) = + 6, epsilonsub(Sr) = -13, delta 18 O approx.= 6per mille, variable 206 Pb/ 204 Pb, Ca/Sr approx.= 77, Rb/Ba = 0.1, La/Yb approx.= 11. None of the products exhibit Eu anomalies and all are LREE enriched. There is a strong correlation between 87 Sr/ 86 Sr and differentiation indices. These data are interpreted in terms of a mantle heat source melting young crust bearing zircon and garnet, but not feldspar, followed by intrusion of this crustal reservoir by mantle-derived magma which caused further crustal melting and contaminated the crustal magma system with mafic components. Since 1000 years ago all the eruptions have been from the same reservoir which has displayed a much more gradual re-equilibration of Pb isotopic compositions than other components suggesting that Pb is being transported via a fluid phase. The Nd and Sr isotopic compositions lie along the mantle array and suggest that the mantle underneath Mt. St. Helens is not as depleted as MORB sources. There is no indication of seawater involvement in the source region. (orig.)

  7. The isotopic and chemical evolution of Mount St. Helens

    Science.gov (United States)

    Halliday, A.N.; Fallick, A.E.; Dickin, A.P.; Mackenzie, A.B.; Stephens, W.E.; Hildreth, W.

    1983-01-01

    Isotopic and major and trace element analysis of nine samples of eruptive products spanning the history of the Mt. St. Helens volcano suggest three different episodes; (1) 40,000-2500 years ago: eruptions of dacite with ??{lunate}Nd = +5, ??{lunate}Sr = -10, variable ??18O, 206Pb/204Pb ??? 18.76, Ca/Sr ??? 60, Rb/Ba ??? 0.1, La/Yb ??? 18, (2) 2500-1000 years ago: eruptions of basalt, andesite and dacite with ??{lunate}Nd = +4 to +8, ??{lunate}Sr = -7 to -22, variable ??18O (thought to represent melting of differing mantle-crust reservoirs), 206Pb/204Pb = 18.81-18.87, variable Ca/Sr, Rb/Ba, La/Yb and high Zr, (3) 1000 years ago to present day: eruptions of andesite and dacite with ??{lunate}Nd = +6, ??{lunate}Sr = -13, ??18O ???6???, variable 206Pb/204Pb, Ca/Sr ??? 77, Rb/Ba = 0.1, La/Yb ??? 11. None of the products exhibit Eu anomalies and all are LREE enriched. There is a strong correlation between 87Sr/86Sr and differentiation indices. These data are interpreted in terms of a mantle heat source melting young crust bearing zircon and garnet, but not feldspar, followed by intrusion of this crustal reservoir by mantle-derived magma which caused further crustal melting and contaminated the crustal magma system with mafic components. Since 1000 years ago all the eruptions have been from the same reservoir which has displayed a much more gradual re-equilibration of Pb isotopic compositions than other components suggesting that Pb is being transported via a fluid phase. The Nd and Sr isotopic compositions lie along the mantle array and suggest that the mantle underneath Mt. St. Helens is not as depleted as MORB sources. There is no indication of seawater involvement in the source region. ?? 1983.

  8. Isotope geochemistry of xenoliths from East Africa. Implications for development of mantle reservoirs and their interaction

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, R S; O' Nions, R K [Cambridge Univ. (UK). Dept. of Earth Sciences; Dawson, J B [Sheffield Univ. (UK). Dept. of Geology

    1984-05-01

    Pd, Nd and Sr isotope analyses together with U, Pb, Sm, Nd, Rb and Sr concentrations have been obtained for separated phases of lherzolite and bulk rock mafic granulite xenoliths in Recent volcanics from Tanzania. A garnet lherzolite from the Lashaine vent has yielded the least radiogenic Pb (/sup 206/Pb//sup 204/PB=15.55) and Nd (/sup 143/Nd//sup 144/Nd=0.51127; epsilon/sup 0/sub(Nd)=-26.7) isotope compositions recorded so far for an ultramafic xenolith, and /sup 87/Sr//sup 86/Sr=0.83604. The Pb isotope compositions of the mafic granulites are variable 15.77isotope results suggest that the mantle part of the continental lithosphere beneath Tanzania has components that have undergone a complex history that includes major chemical fractionations ca. 2.0 Ga ago. A phlogopite-amphibole vein from the Pello Hill sample has Sr, Nd and Pb isotope compositions similar to those of mid-ocean ridge basalts, indicating both a young emplacement age for the vein material and a source which had an isotopic signature characteristic of depleted mantle. The Sr, Nd and Pb isotope systematics of ultramafic xenoliths do not conform with those of MORB, particularly in terms of their Pb-Sr, and Nd-Pb relationship. In this regard they are similar to some ocean islands and could be a viable source material for some ocean island basalts at least. The mantle part of the continental lithosphere is as likely to contain recycled components derived from the continental crust as are other regions of mantle. If the mantle part of continental lithosphere is invoked as a source for ocean islands, it does not negate the possibility that substantial recycled components are involved.

  9. U-Pb, Sm-Nd and Rb-Sr systematics of mid-ocean ridge basalt glasses

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, R S; Evensen, N M; Hamilton, P J; O' Nions, R K [Columbia Univ., Palisades, NY (USA). Lamont-Doherty Geological Observatory

    1980-01-10

    The measurement of Pb, Nd and Sr isotopes in basalt glasses from mid-ocean ridges reveals correlations in isotope parameters which have important implications for the differentiation history of the mantle.

  10. Pb and Sr isotopes and trace metals in molluscs: constraints on metal sources and water fluxes in a coastal lagoon (Thau, France); Isotope du Pb, du Sr et metaux traces dans les mollusques: contraintes sur les sources de metaux et les mouvements d'eaux dans une lagune cotiere (Thau, France)

    Energy Technology Data Exchange (ETDEWEB)

    Labonne, M

    1998-07-01

    Because of its unique ability to characterize the origins and quantify the fluxes of waters and their loads, isotopic geochemistry is being increasingly used in environmental problems. On the other hand, molluscs are known to concentrate metals in a very strong manner and equilibrate relatively rapidly with their environment. They are used in many programs of coastal survey (Mussel Watch, RNO,...). The originality of our work is to apply isotopic systems (Pb, Sr) to living organisms, in order to: 1- identify the metal sources; 2- determine their proportions in the lagoon and 3- to trace the water movements. The Thau lagoon (Herault, S. France) presents various potential sources of metals inputs: heavy traffic road, Sete harbour, various industries (cement factory, fertilizers...), agriculture, camping areas and leisure ports, not to mention natural (rock) sources. Our study deals with the metal and alkali, alkali-earth concentrations, Pb and Sr isotopes determined on both mussels implanted in the lagoon and wild mussels. We also compare our mussel results with those determined on clams which live at the water/sediments interface. A first study deals with the metal accumulation in laboratory experiments using mono-isotopic tracers 'spike'. It shows that the new metal is being superimposed to the metals initially present in the organisms; this effect is seen within a few days, although variable depending on elements (Zn, Cd, Pb). We have sampled the introduced mussels 4 times a year and we see that the concentration fluctuations are principally related to animal weight variations. The flesh isotopic compositions usually define nice alignments depending on season, indicative of a progressive mixing between two main components: one natural, one anthropogenic. Depending on winds,two influences of seawater entries orlocal water treatment plants effluents can be shown. We have compared past and present metal levels and origins in the area by analysing also

  11. The First New Zealanders? An Alternative Interpretation of Stable Isotope Data from Wairau Bar, New Zealand.

    Directory of Open Access Journals (Sweden)

    Andrew A Brown

    Full Text Available PLOS ONE Volume 8 includes an article "The First New Zealanders: Patterns of Diet and Mobility Revealed through Isotope Analysis". The paper proposes that burial groups within the settlement phase site of Wairau Bar differ in terms of dietary stable isotopes and 87Sr/86Sr. The authors argue this difference is probably due to one group being a founding population while the other burials are later. Here we review the work of Kinaston et al. and present an alternative analysis and interpretation of the isotopic data. Treating the isotope data independently from cultural and biological factors we find that sex best explains dietary variation. Our reassessment of 87Sr/86Sr confirms the authors original finding of high mobility of early New Zealanders but suggests a larger range of individuals should be considered 'non-local' on current evidence.

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

    Science.gov (United States)

    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.

  13. Accurate determination and certification of bromine in plastic by isotope dilution inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ohata, Masaki, E-mail: m-oohata@aist.go.jp; Miura, Tsutomu

    2014-07-21

    Highlights: • Accurate analytical method of Br in plastic was studied by isotope dilution ICPMS. • A microwave acid digestion using quartz vessel was suitable for Br analysis. • Sample dilution by NH{sub 3} solution could remove memory effect for ICPMS measurement. • The analytical result of the ID-ICPMS showed consistency with that of INAA. • The ID-ICPMS developed could apply to certification of Br in candidate plastic CRM. - Abstract: The accurate analytical method of bromine (Br) in plastic was developed by an isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The figures of merit of microwave acid digestion procedures using polytetrafluoroethylene (PTFE) or quartz vessels were studied and the latter one was suitable for Br analysis since its material was free from Br contamination. The sample dilution procedures using Milli-Q water or ammonium (NH{sub 3}) solution were also studied to remove memory effect for ICPMS measurement. Although severe memory effect was observed on Milli-Q water dilution, NH{sub 3} solution could remove it successfully. The accuracy of the ID-ICPMS was validated by a certified reference material (CRM) as well as the comparison with the analytical result obtained by an instrumental neutron activation analysis (INAA) as different analytical method. From these results, the ID-ICPMS developed in the present study could be evaluated as accurate analytical method of Br in plastic materials and it could apply to certification of Br in candidate plastic CRM with respect to such regulations related to RoHS (restriction of the use of hazardous substances in electrical and electronics equipment) directive.

  14. Controls over δ44/40Ca and Sr/Ca variations in coccoliths: New perspectives from laboratory cultures and cellular models

    Science.gov (United States)

    Mejía, Luz María; Paytan, Adina; Eisenhauer, Anton; Böhm, Florian; Kolevica, Ana; Bolton, Clara; Méndez-Vicente, Ana; Abrevaya, Lorena; Isensee, Kirsten; Stoll, Heather

    2018-01-01

    Coccoliths comprise a major fraction of the global carbonate sink. Therefore, changes in coccolithophores' Ca isotopic fractionation could affect seawater Ca isotopic composition, affecting interpretations of the global Ca cycle and related changes in seawater chemistry and climate. Despite this, a quantitative interpretation of coccolith Ca isotopic fractionation and a clear understanding of the mechanisms driving it are not yet available. Here, we address this gap in knowledge by developing a simple model (CaSri-Co) to track coccolith Ca isotopic fractionation during cellular Ca uptake and allocation to calcification. We then apply it to published and new δ 44 / 40 Ca and Sr/Ca data of cultured coccolithophores of the species Emiliania huxleyi and Gephyrocapsa oceanica. We identify changes in calcification rates, Ca retention efficiency and solvation-desolvation rates as major drivers of the Ca isotopic fractionation and Sr/Ca variations observed in cultures. Higher calcification rates, higher Ca retention efficiencies and lower solvation-desolvation rates increase both coccolith Ca isotopic fractionation and Sr/Ca. Coccolith Ca isotopic fractionation is most sensitive to changes in solvation-desolvation rates. Changes in Ca retention efficiency may be a major driver of coccolith Sr/Ca variations in cultures. We suggest that substantial changes in the water structure strength caused by past changes in temperature could have induced significant changes in coccolithophores' Ca isotopic fractionation, potentially having some influence on seawater Ca isotopic composition. We also suggest a potential effect on Ca isotopic fractionation via modification of the solvation environment through cellular exudates, a hypothesis that remains to be tested.

  15. The geographic distribution of strontium isotopes in Danish surface waters - A base for provenance studies in archaeology, hydrology and agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Frei, Karin M., E-mail: kmfrei@hum.ku.dk [Danish National Research Foundation Centre for Textile Research, SAXO Institute, University of Copenhagen, Njalsgade 80, DK-2300 Copenhagen (Denmark); Frei, Robert [Institute of Geography and Geology and Nordic Center for Earth Evolution (NordCEE), University of Copenhagen, Oster Voldgade 10, DK-1350 Copenhagen (Denmark)

    2011-03-15

    Research highlights: {yields} Strontium isotope data of 192 surface waters from Denmark. {yields} Geographic baseline distribution of bio-available fractions. {yields} Applicable for provenance studies within archaeology, geology, agriculture and hydrology. {yields} Proposal of a band of strontium isotope values to characterize 'local' Danish signatures. - Abstract: In this paper Sr isotope signatures are reported for 192 surface water (lakes/ponds and rivers/creeks) samples from within Denmark and an isotope distribution map is presented that may serve as a base for provenance applications, including archaeological migration studies, ground water - surface water - seawater interaction/contamination monitoring, and potentially for agricultural applications, including cases of authenticity proof for particular food products. The Sr isotopic compositions of surface waters range from {sup 87}Sr/{sup 86}Sr = 0.7078 to 0.7125 (average 0.7096 {+-} 0.0016; 2{sigma}). This average value lies above the range of {sup 87}Sr/{sup 86}Sr values between 0.7078 and 0.7082 expected from Late Cretaceous to Early Tertiary (Oligocene) limestones which form the dominant bedrock type in a NW-SE trending belt in Denmark. The elevated {sup 87}Sr/{sup 86}Sr signatures >{approx}0.7095 are explained by additions to the surface waters of radiogenic Sr predominantly derived from the near-surface weathering and wash-out of Quarternary glaciogenic tills and soils deposited and formed during and after the last two ice age stages (Saale and Weichsel). The Sr isotopic compositions and concentrations of the surface waters can, therefore, best be modeled by a two-component mixing involving carbonaceous bedrock and glaciogenic cover sediments as the two predominant Sr sources. A feasibility study for using Sr isotopic compositions of surface waters as a proxy for bio-available Sr signatures was conducted in a representative test area on Zealand (Land of Legends, Lejre) where there is no use

  16. The geographic distribution of strontium isotopes in Danish surface waters - A base for provenance studies in archaeology, hydrology and agriculture

    International Nuclear Information System (INIS)

    Frei, Karin M.; Frei, Robert

    2011-01-01

    Research highlights: → Strontium isotope data of 192 surface waters from Denmark. → Geographic baseline distribution of bio-available fractions. → Applicable for provenance studies within archaeology, geology, agriculture and hydrology. → Proposal of a band of strontium isotope values to characterize 'local' Danish signatures. - Abstract: In this paper Sr isotope signatures are reported for 192 surface water (lakes/ponds and rivers/creeks) samples from within Denmark and an isotope distribution map is presented that may serve as a base for provenance applications, including archaeological migration studies, ground water - surface water - seawater interaction/contamination monitoring, and potentially for agricultural applications, including cases of authenticity proof for particular food products. The Sr isotopic compositions of surface waters range from 87 Sr/ 86 Sr = 0.7078 to 0.7125 (average 0.7096 ± 0.0016; 2σ). This average value lies above the range of 87 Sr/ 86 Sr values between 0.7078 and 0.7082 expected from Late Cretaceous to Early Tertiary (Oligocene) limestones which form the dominant bedrock type in a NW-SE trending belt in Denmark. The elevated 87 Sr/ 86 Sr signatures >∼0.7095 are explained by additions to the surface waters of radiogenic Sr predominantly derived from the near-surface weathering and wash-out of Quarternary glaciogenic tills and soils deposited and formed during and after the last two ice age stages (Saale and Weichsel). The Sr isotopic compositions and concentrations of the surface waters can, therefore, best be modeled by a two-component mixing involving carbonaceous bedrock and glaciogenic cover sediments as the two predominant Sr sources. A feasibility study for using Sr isotopic compositions of surface waters as a proxy for bio-available Sr signatures was conducted in a representative test area on Zealand (Land of Legends, Lejre) where there is no use and application of commercial fertilizers. It is demonstrated that

  17. Strontium isotopes in carbonate deposits at Crater Flat, Nevada

    International Nuclear Information System (INIS)

    Marshall, B.D.; Futa, K.; Peterman, Z.E.; Stuckless, J.S.

    1991-01-01

    Strontium isotope studies of carbonates from soils, veins, eolian dust and Paleozoic basement sampled near Crater Flat, southwest of Yucca Mountain, provide evidence for the origins of these materials. Vein and soil carbonates have nearly identical ranges of 87 Sr/ 86 Sr, and eolian material has 87 Sr/ 86 Sr ratios at the lower end of the pedogenic range. The average 87 Sr/ 86 Sr of Paleozoic basement from Black Marble Hill is similar to the 87 Sr/ 86 Sr in the eolian dust, perhaps indicating a local source for this material. Possible spring deposits have generally higher 87 Sr/ 86 Sr than the other carbonates. These data are compared with similar data from areas east of Yucca Mountain

  18. Effect of mycorrhizal infection on root uptake by pine seedlings and redistribution of three contrasting radio-isotopes: 85Sr, 95mTc and 137Cs

    International Nuclear Information System (INIS)

    Plassard, C.; Ladeyn, I.; Staunton, S.

    2004-01-01

    Mycorrhizal infection is known to improve phosphate nutrition and water supply of higher plants. It has been reported to both increase the uptake of potentially toxic pollutant elements and to protect plants against toxic effects. Little is known about the effect of mycorrhizal infection on the dynamics of radioactive pollutants in soil-plant systems. The aim of this study was to compare the root uptake and root-shoot transfer of three radio-isotopes with contrasting chemical properties ( 85 Sr, 95m Tc and 137 Cs) in mycorrhizal and control, non mycorrhizal plants. The plant studied was Pinus pinaster and the associated ecto-mycorrhizal fungus was Rhizopogon roseolus (strain R18-2). Plants were grown under anoxic conditions for 3 months then transferred to thin layers of autoclaved soil and allowed to grow for four months. After this period, the rhizotrons were dismantled, and plant tissue analysed. Biomass, nutrient content (K, P, N, Ca) and activities of each isotope in roots, shoots and stems were measured, and the degree of mycorrhizal infection assessed. The transfer factors decreased in the order Tc>Sr>Cs as expected from the degree of immobilisation by soil. No effect of mycorrhizal infection on root uptake was observed for Sr. Shoot activity concentration of Tc was decreased by mycorrhizal infection but root uptake correlated well with mycelial soil surface area. In contrast, Cs shoot activity was greater in mycorrhizal than control plants. The uptake and root to shoot distribution shall be discussed in relation to nutrient dynamics. (author)

  19. Using 87Sr/86Sr ratios to investigate changes in stream chemistry during snowmelt in the Provo River, Utah, USA

    Science.gov (United States)

    Hale, C. A.; Carling, G. T.; Fernandez, D. P.; Nelson, S.; Aanderud, Z.; Tingey, D. G.; Dastrup, D.

    2017-12-01

    Water chemistry in mountain streams is variable during spring snowmelt as shallow groundwater flow paths are activated in the watershed, introducing solutes derived from soil water. Sr isotopes and other tracers can be used to differentiate waters that have interacted with soils and dust (shallow groundwater) and bedrock (deep groundwater). To investigate processes controlling water chemistry during snowmelt, we analyzed 87Sr/86Sr ratios, Sr and other trace element concentrations in bulk snowpack, dust, soil, soil water, ephemeral channels, and river water during snowmelt runoff in the upper Provo River watershed in northern Utah, USA, over four years (2014-2017). Strontium concentrations in the river averaged 20 ppb during base flow and decreased to 10 ppb during snowmelt runoff. 87Sr/86Sr ratios were around 0.717 during base flow and decreased to 0.715 in 2014 and 0.713 in 2015 and 2016 during snowmelt, trending towards less radiogenic values of mineral dust inputs in the Uinta Mountain soils. Ephemeral channels, representing shallow flow paths with soil water inputs, had Sr concentrations between 7-20 ppb and 87Sr/86Sr ratios between 0.713-0.716. Snowpack Sr concentrations were generally soils that contain accumulated dust deposits with a less radiogenic 87Sr/86Sr ratio. These results suggest that flow paths and atmospheric dust are important to consider when investigating variable solute loads in mountain streams.

  20. Zircon U-Pb chronology, geochemistry and Sr-Nd-Pb isotopic compositions of the Volcanic Rocks in the Elashan area, NW China: petrogenesis and tectonic implications

    Science.gov (United States)

    Zhou, H.; Wei, J.; Shi, W.; Li, P.; Chen, M.; Zhao, X.

    2017-12-01

    Elashan area is located in the intersection of the East Kunlun Orogenic Belt (EKOB) and the West Qinling Orogenic (WQOB). We present petrology, zircon U-Pb ages, whole-rock geochemistry and Sr-Nd-Pb isotopic compositions from the andesite and felsic volcanic rocks (rhyolite and rhyolitic tuffs) in Elashan group volcanic rock. The LA-ICP-MS zircon U-Pb age data indicate that the volcanic rocks are emplaced at 250 247 Ma. The volcanic rocks have high -K and aluminum - peraluminous characteristics, A/CNK = 1.07 1.82, δ ranges from 1.56 2.95, the main body is calc-alkaline rock. They are enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in some high field strength elements (HFSEs, e.g., Nb, Ta, P and Ti), while having a flat heavy REE (HREEs) pattern. The ∑REE values of 178.68 to 298.11 ppm, average 230.50 ppm. The LREE/HREE values of 4.39 to 11.78 ppm, average 6.77 ppm. REE fractionation is obvious, REE distribution curve was right smooth, and have slightly negative Eu anomalies (Eu/Eu*=0.44-0.80, average 0.60), which as similar to the island arc volcanic rocks. The volcanic rocks have initial 87Sr/86Sr ratios of 0.71028-0.71232, ɛNd(t) values of -6.7 to -7.6, with T2DM-Nd ranging from 1561 to 1640 Ma. Pb isotopic composition (206 Pb / 204 Pb)t = 18.055 18.330, (207 Pb / 204 Pb)t = 15.586 15.618, (208 Pb / 204 Pb)t = 37.677 38.332. Geochemical and Sr-Nd-Pb isotopes indicates that Elashan group volcanic magma derived mainly from the lower crust. Elashan group volcanic rocks is the productive East Kunlun block and West Qinling block collision, which makes the thicken crust caused partial melting in the study area. The source rocks is probably from metamorphic sandstone of Bayankala. But with Y-Nb and Rb-(Y+Nb), R1-R2 and Rb/10-Hf-Ta*3 diagrams showing that intermediate-acid rocks mainly formed in volcanic arc-collision environment, probably the collision event is short , therefore rocks retain the original island

  1. Clay mineralogy, strontium and neodymium isotope ratios in the sediments of two High Arctic catchments (Svalbard)

    Science.gov (United States)

    Hindshaw, Ruth S.; Tosca, Nicholas J.; Piotrowski, Alexander M.; Tipper, Edward T.

    2018-03-01

    The identification of sediment sources to the ocean is a prerequisite to using marine sediment cores to extract information on past climate and ocean circulation. Sr and Nd isotopes are classical tools with which to trace source provenance. Despite considerable interest in the Arctic Ocean, the circum-Arctic source regions are poorly characterised in terms of their Sr and Nd isotopic compositions. In this study we present Sr and Nd isotope data from the Paleogene Central Basin sediments of Svalbard, including the first published data of stream suspended sediments from Svalbard. The stream suspended sediments exhibit considerable isotopic variation (ɛNd = -20.6 to -13.4; 87Sr / 86Sr = 0.73421 to 0.74704) which can be related to the depositional history of the sedimentary formations from which they are derived. In combination with analysis of the clay mineralogy of catchment rocks and sediments, we suggest that the Central Basin sedimentary rocks were derived from two sources. One source is Proterozoic sediments derived from Greenlandic basement rocks which are rich in illite and have high 87Sr / 86Sr and low ɛNd values. The second source is Carboniferous to Jurassic sediments derived from Siberian basalts which are rich in smectite and have low 87Sr / 86Sr and high ɛNd values. Due to a change in depositional conditions throughout the Paleogene (from deep sea to continental) the relative proportions of these two sources vary in the Central Basin formations. The modern stream suspended sediment isotopic composition is then controlled by modern processes, in particular glaciation, which determines the present-day exposure of the formations and therefore the relative contribution of each formation to the stream suspended sediment load. This study demonstrates that the Nd isotopic composition of stream suspended sediments exhibits seasonal variation, which likely mirrors longer-term hydrological changes, with implications for source provenance studies based on fixed

  2. Strontium and neodymium isotopic evidence for the heterogeneous nature and development of the mantle beneath Afar (Ethiopia)

    Energy Technology Data Exchange (ETDEWEB)

    Betton, P.J. (Leeds Univ. (UK). Dept. of Earth Sciences); Civetta, L. (Naples Univ. (Italy). Dipartimento di Geofisica e Vulcanologia)

    1984-11-01

    Neodymium isotope and REE analyses of recent volcanic rocks and spinel lherzolite nodules from the Afar area are reported. The /sup 143/Nd//sup 144/Nd ratios of the volcanic rocks range from 0.51286 to 0.51304, similar to the range recorded from Iceland. However, the /sup 87/Sr//sup 86/Sr ratios display a distinctly greater range (0.70328-0.70410) than those reported from the primitive rocks of Iceland. Whole rock samples and mineral separates from the spinel lherzolite nodules exhibit uniform /sup 143/Nd//sup 144/Nd ratios (ca. 0.5129) but varied /sup 87/Sr//sup 86/Sr ratios in the range 0.70427-0.70528. The Sr-Nd isotope variations suggest that the volcanic rocks may have been produced by mixing between two reservoirs with distinct isotopic compositions. Two possible magma reservoirs in this area are the source which produced the 'MORB-type' volcanics in the Red Sea and Gulf of Aden and the anomalous source represented by the nodule suite. The isotopic composition of the volcanics is compatible with mixing between these two reservoirs. It is shown that the anomalous source with a high /sup 87/Sr//sup 86/Sr ratio cannot have been produced by simple processes of partial melting and mixing within normal mantle. Instead the high /sup 87/Sr//sup 86/Sr is equated with a fluid phase. A primitive cognate fluid, subducted seawater or altered oceanic lithosphere may have been responsible for the generation of the source with a high /sup 87/Sr//sup 86/Sr ratio.

  3. Isotopic studies of marbles in the Sanbagawa metamorphic terrain, central Shikoku, Japan

    International Nuclear Information System (INIS)

    Wada, Hideki; Enami, Masaki; Yanagi, Takeru.

    1984-01-01

    Carbon, oxygen and strontium isotopic studies were carried out on marbles occurring in crystalline schists and epidote amphibolites of the Sanbagawa metamorphic terrain, central Shikoku, Japan, in order to estimate metamorphic temperatures and to elucidate their origin. Carbon isotopic fractionation between calcite and graphite shows the metamorphic temperature of 460 deg C at the transitional part between the garnet and albite-biotite zones. Marbles are isotopically classified into two groups. (1) some marbles in epidote amphibolite masses show characteristically negative delta 13 C values and low 87 Sr/ 86 Sr ratios. These marbles are interpreted as have been derived from magmatic or deep-seated carbonates. (2) marbles collected from the crystalline schists and from the marginal part of epidote amphibolite masses, have high 87 Sr/ 86 Sr ratios and delta 13 C values similar to those of typical sedimentary carbonates. They were probably derived from sedimentary carbonates and/or carbonates re-equilibrated with metamorphic fluid segregated from crystalline schists during the Sanbagawa metamorphism. (author)

  4. Limitation of secondary electron multiplier non-linearity on accurate U-Th isotopic determination by MC-ICP-MS

    Science.gov (United States)

    Shen, C.; Wu, C.; Gallet, S.; Cheng, H.; Edwards, R.; Hsieh, Y.; Lin, K.

    2008-12-01

    Contemporary multicollector-inductively coupled plasma mass spectrometry (MC-ICP-MS) with discrete dynode secondary electron multipliers (SEMs) can offer U-Th isotopic determinations with subpermil-permil- level precision in femtogram quantities. However, accurate isotopic measurement requires fully understanding SEM mass and intensity biases. In additional to dead-time effect, Richter et al (2001, Int. J. Mass Spectrom., 206, 105-127) reported a nonlinearity on SEMs produced by ETP and MasCom for count rates > 20 thousand counts per second (cps). We evaluated the possible biases for ion beams of 500- 1,600,000 cps on a latest MasCom SEM, SEV TE-Z/17, with more effective ion optical acceptance area (>50%) and better peak shape than previous models, used in a MC-ICP-MS, Thermo Fisher NEPTUNE. With the retarding potential quadruple lens (RPQ) turned off, ion beam intensity can be biased by only dead- time effect, which can be precisely corrected online or offline. With the RPQ on, two additional biases, an exponential-like increase of ion beam intensity from 100-100,000 s cps and an apparent dead-time effect (-2 to 2 ns) at high count rates, are observed. They are likely caused by the slightly defocused ions with a wide kinetic energy spread of ~5 eV, 10 times worse than that with thermal source, passing through the RPQ lens to the SEM, which is installed behind the focal plane. Fortunately, the two biases, which are stable during the daily measurements with the same settings of inlet system, source lenses, zoom optics, and RPQ, can be corrected effectively offline to earn accurate U-Th isotopic measurement.

  5. Identification of the neutron-rich nuclides /sup 147; 148/Ba and half- life determination of the heavy isotopes of Rb, Sr, Y, Cs, Ba and La

    CERN Document Server

    Amiel, S; Nir-El, Y; Shmid, M

    1976-01-01

    The neutron nuclides /sup 147; 148/Ba were produced in the thermal neutron induced fission of /sup 235/U. A new surface ionization integrated target ion source operating at temperatures in the region of 1800 degrees C permits the measurement of half-lives of isotopes down to about 0.1 sec due to the very fast release of atoms from the target. Isotopes of Rb, Sr, Cs, and Ba were separated by positive surface ionization and their half-lives measured using beta activity detected by a silicon surface barrier detector with a depletion depth of 300 mu . The isotopes /sup 147/Ba and /sup 148/Ba were identified for the first time and their half-lives were found to be 0.72+or-0.07 sec and 0.47+or-0.20 sec, respectively. (0 refs).

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

    Science.gov (United States)

    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. Age of meta-rhyolite of Marata sequence, Araxa Group, Goias: geochronology study by U-Pb in zircon, Rb-Sr and Sm-Nd methods

    International Nuclear Information System (INIS)

    Pimentel, M.M.; Heaman, L.; Fuck, R.A.

    1992-01-01

    U-Pb isotopic analyses in eight zircon fractions separated from a meta-rhyolite sample of the Marata sequence (Araxa Group, Goias) are presented. Two morphologically distinct zircon populations were identified: stubby prismatic crystals (width:length of 1:2 to 1:3) in which core-overgrowth relationships are observed; long prismatic crystals (needles) with width:length ratios of ca. 1:10. Analyses performed on group zircons indicated the presence of a ca. 2.0 Ga. old inherited component. Analyses of group zircons plot very close to the concordia and yield an upper intercepts age of 794 ± 10 Ma for the crystallization of the volcanic protolith. The study was complemented with whole-rock isotopic analyses by the Rb-Sr and Sm-Nd methods. Rb-Sr isochron obtained with samples from two different outcrops gave data of 829 ± 82 Ma (initial 87 Sr/ 86 Sr of 0.7057 ± 0.0157) and 691 ± 30 Ma (initial 87 Sr/ 86 Sr of 0.7337 ± 0.0034). The latter reflects a later Sr-isotopic re-homogenization episode, possibly associated with the intense deformation and metamorphism suffered by these rocks. Sm-Nd isotopic analyses on three samples reveal EN d (T) (T =794 Ma) values in the range of -6.1 to -9.5 which indicate the presence of older (early Proterozoic) crustal Nd. This is consistent with the inheritance pattern shown in the U-Pb isotopic results. (author)

  8. Rb-Sr age estimation of granites-gneisses of Belopotokskij type (Soviet Carpathians)

    International Nuclear Information System (INIS)

    Stepanyuk, L.M.; Kotlovskaya, F.I.; Dovbush, T.I.

    1987-01-01

    Using rubidium-strontium method the age of granito-gneisses of Belopotokskij type of 470 ± 6 mln. years, which agree with isotopic age (459 ± 6 mln. years) obtained by uranium-lead isochronous method using syngenetic zircon, is established. The latter testifies to the manifestation of magmatic activity 460-470 mln. years ago. The low initial ratio of strontium isotopes 87 Sr/ 86 Sr and results of petrographic study of fel spars are indicative of magmatic nature of initial granites and plutonic (mantle or lower crust) source of magma, crystallization of which was the beginning of the Belopotokskij type granito-gneiss formation

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

    Science.gov (United States)

    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.

  10. High-precision γ -ray spectroscopy of the cardiac PET imaging isotope 82Rb and its impact on dosimetry

    Science.gov (United States)

    Nino, M. N.; McCutchan, E. A.; Smith, S. V.; Lister, C. J.; Greene, J. P.; Carpenter, M. P.; Muench, L.; Sonzogni, A. A.; Zhu, S.

    2016-02-01

    82Rb is a positron-emitting isotope used in cardiac positron emission tomography (PET) imaging which has been reported to deliver a significantly lower effective radiation dose than analogous imaging isotopes like 201Tl and 99 mTc sestamibi. High-quality β -decay data are essential to accurately appraise the total dose received by the patients. A source of 82Sr was produced at the Brookhaven Linac Isotope Producer (BLIP), transported to Argonne National Laboratory, and studied with the Gammasphere facility. Significant revisions have been made to the level scheme of 82Kr including 12 new levels, 50 new γ -ray transitions, and the determination of many new spin assignments through angular correlations. These new high-quality data allow a precise reappraisal of the β -decay strength function and thus the consequent dose received by patients.

  11. Rb-Sr and Sm-Nd chronology and genealogy of mare basalts from the Sea of Tranquility

    Science.gov (United States)

    Papanastassiou, D. A.; Depaolo, D. J.; Wasserburg, G. J.

    1977-01-01

    Rb-Sr and Sm-Nd ages of two Apollo 11 mare basalts, high-K basalt 10072 and low-K basalt 10062, are reported. Rb-Sr, Sm-Nd, and Ar-40-Ar-39 ages are in good agreement and indicate an extensive time interval for filling of the Sea of Tranquility, presumably by thin lava flows, in agreement with similar observations for the Ocean of Storms. Initial Sr and Nd isotopic compositions on Apollo 11 basalts reveal at least two parent sources producing basalts. The Sm-Nd isotopic data demonstrate that low-K and high-Ti basalts from Apollo 11 and 17 derived from distinct reservoirs, while low-Ti Apollo 15 mare basalt sources have Sm/Nd similar to the sources of Apollo 11 basalts. Groupings of mare basalt based on Ti content and on isotopic data do not coincide.

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

    Science.gov (United States)

    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

  13. Permian alkali granitoids of the transbaikal region (new Rb-Sr dates)

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, M K; Ryakhovskij, V M; Abramov, A V

    1984-01-01

    Rubidium-strontium isotopic investigations of granitoids from Khorinsk and Middle Oninsk massifs were conducted. Isochrones for two chief-modifications of rocks - subalkaline syenites and alkaline granites-were constructed. The age of syenites is determined to be (293 + 20) x 10/sup 6/ at (/sup 87/Sr//sup 86/Sr)/sub 0/=0.7044 +- 0.0106 that of alkaline granites - (253 +- 3) x 10/sup 6/ at (/sup 87/Sr//sup 86/Sr)/sub 0/=0.7077 +- 0.0033. Analytical data for determination of rubidium-strontium age of rocks of the mentioned massits are presented as well.

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

    Science.gov (United States)

    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.

  15. Accurate quantification of polycyclic aromatic hydrocarbons in dust samples using microwave-assisted solvent extraction combined with isotope-dilution mass spectrometry

    International Nuclear Information System (INIS)

    Itoh, Nobuyasu; Fushimi, Akihiro; Yarita, Takashi; Aoyagi, Yoshie; Numata, Masahiko

    2011-01-01

    Highlights: → We applied MAE-IDMS for accurate quantification of PAHs in dust samples. → Both partitioning and isotopic equilibria can be achieved using this technique. → MAE-IDMS can provide accurate concentrations even if extraction efficiencies were low. → Characteristics of samples strongly affected for low extraction efficiencies of PAHs. - Abstract: For accurate quantification of polycyclic aromatic hydrocarbons (PAHs) in dust samples, we investigated the use of microwave-assisted solvent extraction (MAE) combined with isotope-dilution mass spectrometry (IDMS) using deuterium-labelled PAHs (D-PAHs). Although MAE with a methanol/toluene mixture (1:3 by volume) at 160 deg. C for 40 min was best for extracting PAHs from tunnel dust among examined, the recovery yields of D-PAHs decreased with increasing molecular weight (<40% for MW ≥ 264; that of deuterium-labelled indeno[123-cd]pyrene (D-IcdP) was only 7.1%). Although the residues were extracted a second time, the observed concentrations did not change dramatically (<5%), and the recovery yields of heavier D-PAHs (i.e., MW ≥ 264) were approximately half of those of the first extract, including D-IcdP (3.4%). These results suggest that both partitioning and isotopic equilibria of PAHs and D-PAHs between sample and solvent were achieved for extractable heavier PAHs under the condition. Thus, the observed concentrations of PAHs obtained by MAE-IDMS were reasonable, even though recovery yields of D-PAHs were <50%. From the results of carbon analyses and extractable contents, lower recovery yields of D-PAHs from the tunnel dust were due to a large content of char with low extractable contents.

  16. 87Sr/86Sr in gypsic soils of hyperarid settings as an altitude proxy: results for northern Chile (19-22°S) and paleoaltimetry applications

    Science.gov (United States)

    Cosentino, N. J.; Jordan, T. E.; Derry, L. A.

    2012-12-01

    Quantification of uplift of a continental surface relative to sea level is still challenging. We have developed a new altimeter based on the 87Sr/86Sr ratio of modern accumulations of salts (incipient soils) in hyperarid settings like those present in northern Chile's Atacama Desert, which lies in the forearc of the Nazca-South America plate system. The proposed altimeter is based on the first order topographic control on the extent of coastal fog. Advective events bring offshore-generated stratocumulus clouds to the continent, generating fog between 400 and 1100 m.a.s.l.. In the hyperarid desert, thin layers of calcium sulfate, among other salts, accumulate on the surface. The main sources of the calcium sulfates are i) Pacific-sourced fog that transports aerosols and dissolved salts inland, which are precipitated upon evaporation, ii) wind that transports salts derived from the weathering of Andean magmatic arc rocks, which may be recycled through salars, and to a lesser extent, iii) salts derived from volcanic emissions. While the latter two have an average 87Sr/86Sr isotopic ratio of 0.70749, the fog source has a value corresponding to seawater (0.70917). Due to the high atomic weight of Sr and to the low relative mass difference of isotopes 87Sr and 86Sr, environmental isotopic fractionation is minimal. This makes 87Sr/86Sr an excellent proxy for the primary source of the calcium sulfates and the calcium sulfates' Sr. Samples from four E-W transects of the forearc between 19.75° to 23.75° S demonstrate variations in 87Sr/86Sr for altitudes between 200 and 2700 m.a.s.l.. There is a correlation between the modern salts' 87Sr/86Sr and its altitude of formation for altitudes between ~400 and ~800 m.a.s.l., above which the 87Sr/86Sr falls abruptly until reaching values similar to or lower than the Andean average. The fact that this correlation is observed for the whole dataset (including all four transects) suggests that the relationship is regional rather than

  17. Zircon Lu-Hf isotope systematics and U-Pb geochronology, whole-rock Sr-Nd isotopes and geochemistry of the early Jurassic Gokcedere pluton, Sakarya Zone-NE Turkey: a magmatic response to roll-back of the Paleo-Tethyan oceanic lithosphere

    Science.gov (United States)

    Karsli, Orhan; Dokuz, Abdurrahman; Kandemir, Raif

    2017-05-01

    The early Mesozoic was a critical era for the geodynamic evolution of the Sakarya Zone as transition from accretion to collision events in the region. However, its complex evolutionary history is still debated. To address this issue, we present new in situ zircon U-Pb ages and Lu-Hf isotope data, whole-rock Sr-Nd isotopes, and mineral chemistry and geochemistry data of plutonic rocks to better understand the magmatic processes. The Gokcedere pluton is mainly composed of gabbro and gabbroic diorite. LA-ICP-MS zircon U-Pb dating reveals that the pluton was emplaced in the early Jurassic (177 Ma). These gabbros and gabbroic diorites are characterized by relatively low SiO2 content of 47.09 to 57.15 wt% and high Mg# values varying from 46 to 75. The samples belong to the calc-alkaline series and exhibit a metaluminous I-type character. Moreover, they are slightly enriched in large ion lithophile elements (Rb, Ba, Th and K) and light rare earth elements and depleted in high field strength elements (Nb and Ti). Gabbroic rocks of the pluton have a depleted Sr-Nd isotopic composition, including low initial 87Sr/86Sr ranging from 0.705124 to 0.705599, relatively high ɛ Nd ( t) values varying from 0.1 to 3.5 and single-stage Nd model ages ( T DM1 = 0.65-0.95 Ga). In situ zircon analyses show that the rocks have variable and positive ɛ Hf ( t) values (4.6 to 13.5) and single-stage Hf model ages ( T DM1 = 0.30 to 0.65 Ga). Both the geochemical signature and Sr-Nd-Hf isotopic composition of the gabbroic rocks reveal that the magma of the studied rocks was formed by the partial melting of a depleted mantle wedge metasomatized by slab-derived fluids. The influence of slab fluids is mirrored by their trace-element characteristics. Trace-element modeling suggests that the primary magma was generated by a low and variable degree of partial melting ( 5-15%) of a depleted and young lithospheric mantle wedge consisting of phlogopite- and spinel-bearing lherzolite. Heat to melt the

  18. Strontium isotopes in carbonate deposits at Crater Flat, Nevada

    International Nuclear Information System (INIS)

    Marshall, B.D.; Futa, K.; Peterman, Z.E.; Stuckless, J.S.

    1991-01-01

    Strontium isotope studies of carbonates from soils, veins, eolian dust and Paleozoic basement samples near Crater Flat, southwest of Yucca Mountain, provide evidence for the origins of these materials. Vein and soil carbonates have nearly identical ranges of 87 Sr/ 86 Sr ratios at the lower end of the pedogenic range. The average 87 Sr/ 86 Sr of Paleozoic basement from Black Marble Hill is similar to the 87 Sr/ 86 Sr in the eolian dust, perhaps indicating a local source for this material. Possible spring deposits have generally higher 87 Sr/ 86 Sr than the other carbonates. These data are compared with similar data from areas east of Yucca Mountain. 7 refs., 5 figs

  19. Rb-Sr geochronological study on Tatehira granodiorite, Oshima Peninsula, Southwest Hokkaido, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Iizumi, Shigeru; Kobayashi, Hideo; Toyoda, Minoru

    1984-10-01

    It has been known that Tatehira granodiorite, a pluton which occurs sporadically in the southwest region of Hokkaido, is related with Kanoite formation. The radiometric age of this granodiorite still remains unknown. The Tatehira granodiorite intrudes into late Paleozoic or early Mesozoic Matsumae group, and is overlain by Miocene Usubetsu formation unconformably. It occurs as several separated small plutons. The samples for Rb-Sr analysis were collected from one of the plutons in southern part. The determination of the isochron age of rock-minerals and the initial Sr isotopic ratio of Tatehira granodiorite were carried out. This granodiorite is able to be classified into two phases, namely melanocratic (WRM) and leucocratic (WRL) phases. The samples of WRM and WRL were powdered and subjected to X-ray analysis. It was found that the chemical compositions were similar except slight differences in FeO + Fe2O3, CaO and K2O. The Sr isotopic ratio was determined with a MAT 261 mass spectrometer, and the results were analyzed statistically. The Rb and Sr concentrations and the Sr isotopic ratio of WRM, WRL, and PRF (plagio-clase rich fraction) and BRF (biotite rich fraction) separated from the WRL were determined, and the age of 102.5 +- 0.3 Ma and the initial ratio of 0.70538 +- 0.00001 were obtained. The ratio of Tatehira granodiorite is comparable to that of Okushiri Island. Comparing with the data obtained from other region, the granodiorites of Tatehira and Okushiri Island should be related with the granitoids of Abukuma granite province.

  20. Behaviour of the Sm-Nd and Rb-Sr systems of the mafic-ultramafic layered sequence from Ribeirao dos Motas (Archaean), meridional craton Sao Francisco: evidences of mantle source enrichment and isotopic fractionation; Comportamento dos sistemas Sm-Nd e Rb-Sr da sequencia acamadada mafico-ultramafico Ribeirao dos Motas (Arqueano), craton Sao Francisco Meridional: evidencias de enriquecimento mantelico e fracionamento isotopico

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Mauricio Antonio; Carvalho Junior, Irneu Mendes de; Oliveira, Arildo Henrique de [Ouro Preto Univ., (UFOP), MG (Brazil). Dept. de Geologia]. E-mail: mauricio@degeo.ufop.br; Teixeira, Wilson [Sao Paulo Univ., SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotectonica; Pimentel, Marcio Martins [Brasilia Univ., DF (Brazil). Inst. de Geociencias. Lab. de Geocronologia

    2004-10-15

    The Ribeirao dos Motas layered sequence (SARM) crops out in the southern part of the Sao Francisco Craton, Brazil. This sequence comprises phaneritic meta ultramafic and metamafic rocks, which, although slightly deformed and metamorphosed, retain primary igneous layers. Porphyritic rocks with idiomorphic pyroxene crystals and heteradcumulate and adcumulate textures are also present. Eighteen isotopic analyses were performed in the SARM, comprising rocks with primary (relict) textures, as well as rocks in amphibolite facies and retro-metamorphosed to green-schist facies. Seven samples yield a Sm/Nd isochron age of 2.79 +- 0.30 Ga (MSWD=1.2 e epsilon {sub Ndt}=+0.48), constraining the accretion time of the SARM rocks. The positive epsilon {sub Ndt} value coupled with the Rb/Sr evidence is consistent with mantle source relatively enriched in Nd and Sr isotopes. Nevertheless, some SARM samples display isotopic fractionation and disturbance, which can be ascribed to the following processes or their combinations: a) mobilization of the incompatible elements due to regional high grade metamorphism; b) isotopic changes during upper amphibolite facies overprint; c) isotopic resetting by low-grade fluids associated to the Claudio Shear zone, which is located nearby the SARM. (author)

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

    Science.gov (United States)

    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 CAIextinction 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., 2009 Earth Science J. of CUG [5] Zhao et al., 2013 GPC.

  2. The clay mineral and Sr-Nd isotopic composition for fine-grained fraction of sediments from northwestern South China Sea: implications for sediment provenance

    Science.gov (United States)

    Cai, G.

    2013-12-01

    *Guanqiang Cai caiguanqiang@sina.com Guangzhou Marine Geological Survey, Guangzhou, 510760, P.R. China As the largest marginal sea in the western pacific, the South China Sea (SCS) receives large amount of terrigenous material annually through numerous rivers from surrounding continents and islands, which make it as the good place for the study of source to sink process. Yet few studies put emphasis on the northwestern continental shelf and slope in the SCS, even though most of the detrital materials derived from the Red River and Hainan Island are deposited in this area, and northwestern shelf plays a significant role in directly linking the South China, the Indochina and the South China Sea and thus controlling the source to sink process of terrestrial sediment. We presented the clay mineral and Sr-Nd isotopic composition of fine-grained fraction for sediments from northwestern SCS, in order to identify sediment source and transportation. The results show that the clay mineral of northwestern SCS sediments are mainly illite (30%~59%), smectite (20%~40%) and kaolinite (8%~35%), with minor chlorite. The illite chemical index varies between 0.19 and 0.75 with an average of 0.49, indicating an intensive hydrolysis in the source region. The 87Sr/86Sr ratios of sediments range from 0.716288 to 0.734416 (average of 0.724659), and ɛ Nd(0) values range from -10.31 to -11.62 (average of -10.93), which suggest that the source rocks of these sediments are derived from continental crust. The Hainan Island is an important source for sediments deposited in the nearshore and western shelf, especially for illite, kaolinite and smectite clay minerals. Furthermore, the relatively high contents of kaolinite and smectite in sediments from eastern shelf and southern slope of Hainan Island are also controlled by the supply of terrigenous materials from Hainan, which cannot be resulted from sedimentary differentiation of the Pearl and Red river sediments. And the correlation analysis

  3. Coupled S and Sr isotope evidences for elevated arsenic concentrations in groundwater from the world's largest antimony mine, Central China

    Science.gov (United States)

    Wen, Bing; Zhou, Aiguo; Zhou, Jianwei; Liu, Cunfu; Huang, Yuliu; Li, Ligang

    2018-02-01

    The Xikuangshan(XKS) mine, the world's largest antimony mine, was chosen for a detailed arsenic hydrogeochemical study because of the elevated arsenic in bedrock aquifers used by local residents. Hydrochemical data, δ34S values of dissolved SO42- and 87Sr/86Sr ratios have been analyzed to identify the predominant geochemical processes that control the arsenic mobilization within the aquifers. Groundwater samples can be divided into three major types: low arsenic groundwater (0-50 μg/L), high arsenic groundwater (50-1000 μg/L) and anomalous high arsenic groundwater (>1000 μg/L). Arsenic occurs under oxidizing conditions at the XKS Sb mine as the HAsO42- anion. The Ca/Na ratio correlates significantly with HCO3-/Na and Sr/Na ratios, indicating that carbonate dissolution and silicate weathering are the dominant processes controlling groundwater hydrochemistry. The δ34S values of the groundwater indicate that dissolved SO42- in groundwater is mainly sourced from the oxidation of sulfide minerals, and elevated As concentrations in groundwater are influenced by the mixing of mine water and surface water. Furthermore, the δ34S values are not correlated with dissolved As concentrations and Fe concentrations, suggesting that the reduction dissolution of Fe(III) hydroxides is not the dominant process controlling As mobilization. The 87Sr/86Sr ratios imply that elevated As concentrations in groundwater are primarily derived from the interaction with the stibnite and silicified limestone. More specifically, the excess-Na ion, the feature of Ca/Na ratio, and the spatial association of elevated As concentrations in groundwater collectively suggest that high and anomalous high arsenic groundwater are associated with smelting slags and, in particular, the arsenic alkali residue. In general, the hydrochemistry analysis, especially the S and Sr isotope evidences elucidate that elevated As concentrations and As mobilization are influenced by several geochemical processes

  4. Areal distribution of 60Co, 137Cs, and 90Sr in streambed gravels of White Oak Creek Watershed, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Cerling, T.E.; Spalding, B.P.

    1981-01-01

    The concentrations of 90 Sr, 60 Co, and 137 Cs in streambed gravels from contaminated drainages in White Oak Creek Watershed were determined. Methods to determine the relative contributions of various sources to the total discharge from the watershed were developed. Principal sources of 90 Sr were: ORNL plant effluents (50%), leaching from solid waste disposal area (SWDA) 4 (30%), and leaching from SWDA 5 (10%). Minor sources included SWDA 3, the Molten Salt Reactor Facility, and intermediate-level liquid waste pit 1 with each representing 4% or less of the total basin discharge. The cooling water effluent from the High-Flux Isotope Reactor was the dominant source of 60 Co contamination in the watershed. ORNL plant effluents accounted for almost all the 137 Cs discharge from White Oak Creek basin. Downstream radionuclide concentrations were constant until significant dilution by other tributaries occurred. Any future activities giving rise to additional contamination can now be identified. Distribution coefficients between streambed gravels and streamwater for 85 Sr, 60 Co, and 137 Cs were 50, 560, and 8460 ml/g, respectively. An abridged radiochemical fractionation developed for 90 Sr was found to be as accurate and precise for these samples as the standard 90 Sr method above levels of 2 dpm/g

  5. Spectroscopic Quadrupole Moments in {96,98}Sr: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60.

    Science.gov (United States)

    Clément, E; Zielińska, M; Görgen, A; Korten, W; Péru, S; Libert, J; Goutte, H; Hilaire, S; Bastin, B; Bauer, C; Blazhev, A; Bree, N; Bruyneel, B; Butler, P A; Butterworth, J; Delahaye, P; Dijon, A; Doherty, D T; Ekström, A; Fitzpatrick, C; Fransen, C; Georgiev, G; Gernhäuser, R; Hess, H; Iwanicki, J; Jenkins, D G; Larsen, A C; Ljungvall, J; Lutter, R; Marley, P; Moschner, K; Napiorkowski, P J; Pakarinen, J; Petts, A; Reiter, P; Renstrøm, T; Seidlitz, M; Siebeck, B; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Vermeulen, M; Voulot, D; Warr, N; Wenander, F; Wiens, A; De Witte, H; Wrzosek-Lipska, K

    2016-01-15

    Neutron-rich {96,98}Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60.

  6. Comparisons of multiple isotope systems in the aragonitic shells of cultured Arctica islandica clams

    Science.gov (United States)

    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

  7. Nature and Significance of the High-Sr Aleutian Lavas

    Science.gov (United States)

    Yogodzinski, G. M.; Arndt, S.; Turka, J. R.; Kelemen, P. B.; Vervoort, J. D.; Portnyagin, M.; Hoernle, K.

    2011-12-01

    Results of the Western Aleutian Volcano Expedition and German-Russian KALMAR cruises include the discovery of seafloor volcanism at the Ingenstrem Depression and at unnamed seamounts 300 km west of Buldir, the westernmost emergent volcano in the Aleutian arc. These discoveries indicate that the surface expression of active Aleutian volcanism goes below sea level just west of Buldir, but is otherwise continuous along the full length of the arc. Many lavas dredged from western Aleutian seamounts are basalts, geochemically similar to basalts from elsewhere in Aleutians and other arcs (La/Yb 4-8, Sr/Y700 ppm Sr), which are mostly plagioclase-hornblende andesites and dacites with low Y and middle-heavy rare-earth elements, fractionated trace element patterns (Sr/Y=50-200, La/Yb=9-25) and MORB-like isotopes (87Sr/86Sr 0.65) with 1250-1700 ppm Sr, 4-7 ppm Y, low abundances of all rare-earth elements (LaMexico. [1] Zimmer et al., 2010, J. Petrology, v. 51, p. 2411

  8. Isotopic clues to magmatic source regions for neogene Andean volcanic rocks in the El Teniente area near 38oS latitude

    International Nuclear Information System (INIS)

    Kay, Suzanne Mahlburg; Kurtz, A.C

    2001-01-01

    The origin of isotopic variations in Central Andean arc lavas is a long-standing problem that involves identifying mantle and crustal source regions. Advances have come from analyzing temporal and spatial variations in constrained tectonic settings. The purpose here is to highlight the similarities of temporal variations in an east-west transect of Neogene magmatic units near 34 O S latitude with those from a south-north transect along the modern Southern Volcanic Zone (SVZ, e.g. Hildreth and Moorbath 1988, Tormey et al. 1991). The comparison shows the importance of crustal thickening processes associated with compressional shortening and of lithospheric scale adjustments associated with eastward migration of the arc front on magma sources. Sr, Nd and Pb isotopic analyses of 27 Neogene volcanic and plutonic samples from the El Teniente area are presented in Table 1 and plotted along with some analyses from Skewes and Stern (1994) and Stern and Skewes (1995) in Figure 2. The data show a clear progression from older samples with more 'depleted' isotopic signatures (lower 87 Sr/ 86 Sr and Pb isotopic ratios, higher εNd) to younger samples with more 'enriched' signatures (higher 87 Sr/ 86 Sr and Pb isotopic ratios, lower εNd). In detail, four temporal and spatial groups marked by discontinuities in isotopic trends can be defined. Within each group, εNd tends to decrease and 87 Sr/ 86 Sr ratios to increase with SiO2 concentration (au)

  9. Pattern changes in quantitative and qualitative markers of hematopoietic stem cells during acute and chronic exposure to Sr"9"0 isotope in cell culture

    International Nuclear Information System (INIS)

    Russu, Yi.Z.; Byil'ko, D.Yi.; Byil'ko, N.M.; Rodyionova, N.K.

    2015-01-01

    To study the condition of stem cells and their immediate progenitors we implemented cell culture methodology in vivo in gel diffusion capsules with subsequent analysis of the colonies and clusters. On the basis of experiments it was established that long-term effects of incorporated "9"0 Sr isotope leads to significant disturbances in the hematopoietic system and in particular, revealing changes in hematological parameters of irradiated animals such as the appearance of circulating progenitor cells in peripheral blood, reducing the colony-forming efficiency of the bone marrow derived progenitor cells, as well as quantitative and qualitative changes in the clones. Indices confirm the connection of the detected effects in individuals exposed to ionizing radiation described in the earlier publications and can serve as basis for developing criteria for the formation of risk groups among people exposed to "9"0 Sr

  10. Strontium isotope evidence on the history of oilfield brines, Mediterranean Coastal Plain, Israel

    International Nuclear Information System (INIS)

    Starinsky, A.; Bielski, M.; Lazar, B.; Steinitz, G.; Raab, M.

    1983-01-01

    The isotopic composition of Sr in oil field brines from the Mediterranean Coastal Plain was determined in 18 drillholes. The brines are characterized by salinities ranging from 35 to 93 g/l (TDS), Sr from 28 to 350 mg/l, Sr/Ca molar ratios from 0.011 to 0.053 and 87 Sr/ 86 Sr ratios from 0.7075 to 0.7090. E and A = 0.7081 +- 0.0004 (2σ). The brines are classified into two groups: (a) Mavqi'im group - brines with relatively high 87 Sr/ 86 Sr ratios, sampled from clastics, dolomites and anhydrites of Upper Miocene age. (b) Heletz group - brines with relatively low 87 Sr/ 86 Sr ratios, sampled from sandstones and dolomites of Lower Cretaceous age. Equations were derived to show the relations between 87 Sr/ 86 Sr ratio of the brines and the processes through which they evolved. It is suggested that both groups of brines originated from Mediterranean evaporated seawater during the Messinian desiccation. The strontium isotope composition of the seawater is reflected in that of both groups of brines, the Mavqi'im group containing the original 87 Sr/ 86 Sr ratio. The Heletz group evolved later on, through exchange reactions of those primary brines with a carbonate sequence of Cretaceous age and consequently new 87 Sr/ 86 Sr ratios could have been developed. (author)

  11. Autoradiography of 90Sr in developing rats

    International Nuclear Information System (INIS)

    Olsen, I.; Jonsen, J.

    1979-01-01

    The distribution patterns of 90 Sr in five littermate, 8-day-old Wistar rats were studied by whole body autoradiography. Rats were killed 15 min, 1, 4, 24, and 72 h after a single intraperitoneal injection of the isotope. Immediately after administration, 90 Sr was distributed throughout most of the soft tissues of the body. The soft tissue deposits had practically disappeared after 4 h. In the hard tissues of the body 90 Sr accumulated up to 24-72 h. Fifteen minutes after injection the uptake of 90 Sr in the enamel of the teeth was highest in the occlusal and incisal regions. 90 Sr gradually accumulated throughout the enamel and after 72 h its distribution in this layer was fairly uniform. Immediately after injection a narrow zone of radioactivity appeared in the dentin near the pulp. This zone broadened with time towards the dentinoenamel junction and included the intire dentin layer 72 h after injection. Initially, the uptake of 90 Sr was higher in the dentin than in the enamel, particularly in the cervical areas of the crown. This difference became less apparent with time. There was good correlation between the uptake in the teeth and bones, supporting the use of teeth as indicators of the 90 Sr body burden. (author)

  12. A high 87Sr 86Sr mantle source for low alkali tholeiite, northern Great Basin

    Science.gov (United States)

    Mark, R.K.; Lee, Hu C.; Bowman, H.R.; Asaro, F.; McKee, E.H.; Coats, R.R.

    1975-01-01

    Olivine tholeiites, the youngest Tertiary units (about 8-11 m.y. old) at five widely spaced localities in northeastern Nevada, are geologically related to the basalts of the Snake River Plain, Idaho, to the north and are similar in major element and alkali chemistry to mid-ocean ridge basalts (MORB) and island arc tholeiites. The measured K (1250-3350 ppm), Rb (1??9-6??2 ppm) and Sr (140-240 ppm) concentrations overlap the range reported for MORB. Three of the five samples have low, unfractionated rare earth element (REE) patterns, the other two show moderate light-REE enrichment. Barium concentration is high and variable (100-780 ppm) and does not correlate with the other LIL elements. The rocks have 87Sr/86Sr = 0??7052-0??7076, considerably higher than MORB (~0??702-0??703). These samples are chemically distinct (i.e. less alkalic) from the olivine tholeiites from the adjacent Snake River Plain, but their Sr isotopic compositions are similar. They contain Sr that is distinctly more radiogenic than the basalts from the adjacent Great Basin. About 10 b.y. would be required for the mean measured Rb/Sr (~ 0??02) of these samples to generate, in a closed system, the radiogenic Sr they contain. The low alkali content of these basalts makes crustal contamination an unlikely mechanism. If the magma is uncontaminated, the time-averaged Rb/Sr of the source material must have been ~0??04. A significant decrease in Rb/Sr of the source material (a factor 2??) thus most probably occurred in the relatively recent (1??09 yr) past. Such a decrease of Rb/Sr in the mantle could accompany alkali depletion produced by an episode of partial melting and magma extraction. In contrast, low 87Sr 86Sr ratios indicate that the source material of the mid-ocean ridge basalts may have been depleted early in the Earth's history. ?? 1975.

  13. Isotopic dependence of photoneutron cross sections around Strontium (Z=38) and Cesium (Z=55) nuclei

    International Nuclear Information System (INIS)

    Nakamura, T.; Uno, Y.; Yamadera, A.; Kase, T.

    1992-01-01

    We measured the average cross sections of (γ,n) reactions for 84 Sr, 86 Sr, 88 Sr, 85 Rb, 87 Rb, 98 Ru and 104 Ru isotopes in giant resonance region (9 to 25 MeV) using Bremsstrahlung radiation of 60 MeV maximum energy. We investigated the isotopic dependence of the average (γ,n) cross sections in giant resonance region from our experimental data and those estimated from other experimental data for Ge, Se, Zr, Mo, Sn, Te, Ce, Nd and Sm isotopes. As a result, we found that the average cross section data become highest for nuclei of neutron magic number of N = 50 and 82 except for Mo nucleus

  14. Sr isotope evidence for a lacustrine origin for the upper Miocene to Pliocene Bouse Formation, lower Colorado River trough, and implications for timing of Colorado Plateau uplift

    Science.gov (United States)

    Spencer, J.E.; Patchett, P.J.

    1997-01-01

    The upper Miocene to Pliocene Bouse Formation in the lower Colorado River trough, which consists largely of siltstone with basal tufa and marl, has been interpreted as estuarine on the basis of paleontology. This interpretation requires abrupt marine inundation that has been linked to early rifting in the Gulf of California and Salton trough. New strontium isotope measurements reported here from carbonates and invertebrate shells in the Bouse Formation reveal no evidence of marine water, but are consistent with deposition in a lake or chain of lakes fed by the Colorado River. Furthermore, the absence of a southward decrease in 87Sr/86Sr within the Bouse Formation does not support the estuarine model in which low 87Sr/86Sr marine Sr would have dominated the mouth of the hypothetical Bouse estuary. Elevation of originally marine 87Sr/86Sr in the Bouse Formation to its present level, due to postdepositional interaction with ground water, is unlikely because Sr from secondary calcite above, below, and within the Bouse Formation is consistently less radiogenic, not more, than Bouse marl and shells. In contrast to Bouse Sr, strontium from mollusks in tidal-flat and delta-front paleoenvironments in the contemporaneous Imperial Formation in the Salton trough and from the subsurface south of Yuma was derived from sea water and confirms the dominance of marine strontium near or at the mouth of the late Miocene to early Pliocene Colorado River. Inferred post-early Pliocene uplift of the Bouse Formation from below sea level to modern elevations of up to 550 m has been used to support a late Cenozoic uplift age for the nearby Colorado Plateau. This constraint on uplift timing is eliminated if the Bouse Formation is lacustrine.

  15. Isotope hydrology of the Chalk River Laboratories site, Ontario, Canada

    Science.gov (United States)

    Peterman, Zell; Neymark, Leonid; King-Sharp, K.J.; Gascoyne, Mel

    2016-01-01

    This paper presents results of hydrochemical and isotopic analyses of groundwater (fracture water) and porewater, and physical property and water content measurements of bedrock core at the Chalk River Laboratories (CRL) site in Ontario. Density and water contents were determined and water-loss porosity values were calculated for core samples. Average and standard deviations of density and water-loss porosity of 50 core samples from four boreholes are 2.73 ± 12 g/cc and 1.32 ± 1.24 percent. Respective median values are 2.68 and 0.83 indicating a positive skewness in the distributions. Groundwater samples from four deep boreholes were analyzed for strontium (87Sr/86Sr) and uranium (234U/238U) isotope ratios. Oxygen and hydrogen isotope analyses and selected solute concentrations determined by CRL are included for comparison. Groundwater from borehole CRG-1 in a zone between approximately +60 and −240 m elevation is relatively depleted in δ18O and δ2H perhaps reflecting a slug of water recharged during colder climatic conditions. Porewater was extracted from core samples by centrifugation and analyzed for major dissolved ions and for strontium and uranium isotopes. On average, the extracted water contains 15 times larger concentration of solutes than the groundwater. 234U/238U and correlation of 87Sr/86Sr with Rb/Sr values indicate that the porewater may be substantially older than the groundwater. Results of this study show that the Precambrian gneisses at Chalk River are similar in physical properties and hydrochemical aspects to crystalline rocks being considered for the construction of nuclear waste repositories in other regions.

  16. Indications of a major Neolithic trade route? An archaeometric geochemical and Sr, Pb isotope study on amphibolitic raw material from present day Europe

    International Nuclear Information System (INIS)

    Christensen, A.-M.; Holm, P.M.; Schuessler, U.; Petrasch, J.

    2006-01-01

    In order to interpret pre-historic cultural interactions, the provenance of amphibolitic raw material used for flat-axes and adzes in lower to middle Neolithic cultures throughout present day Germany were investigated by elemental and Sr, Pb isotopic methods. Within all settlements studied, a homogeneous actinolite-hornblende schist rock type (AHS) was found to be massively dominating, with a distinct petrography of needle-shaped actinolite interwoven with single larger grains of hornblende along with calcic plagioclase and large amounts of ilmenite. Geochemically, the AHS group is very homogeneous and has a signature of an enriched basaltic precursor with high concentrations of particularly the LIL-elements. The geochemical signature is relatively rare and can not be matched in nearby geological outcrops, wherefore the conclusion of 'imported material' is quickly reached. Strontium and Pb isotopic analyses of the AHS were compared to the isotopic composition of amphibolitic rocks with similar petrography and trace elemental signatures within possible archaeological trade regions. The isotopic data of the archaeological material point roughly to a Proterozoic age of the stone used; an age which can be reasonable matched to a single outcrop situated at Jistebsko within the Czech Republic. This area further shows archaeological traces of prehistoric mining. Based on petrographic, geochemical and isotopic evidence, this area is here presented as the provenance area of the stone raw material, which later spread throughout prehistoric Europe - establishing contact and trade routes between Neolithic cultures

  17. Physico-chemical reactions in the underground movement of radioactive isotopes

    International Nuclear Information System (INIS)

    Gailledreau, C.

    The physico-chemical state of the radioelements moving underground can influence considerably their migration velocity. In the case of 90 Sr--held on by monmorillonites, apatites, activated aluminum oxide--the occurrence of electronegative colloids, sorbing selectively 90 Sr results in an immediate break-through of this isotope. This phenomenon has been demonstrated in the case of the calcite phosphate reaction. A high pH is generally favorable to 90 Sr sorption (apatite, aluminum oxide). The occurrence of Ca 2+ ions acts very unfavorably on 90 Sr sorption by minerals specifics of this isotope (apatite, aluminum oxide). The same thing occurs with organic matters 137 Cs sorption, attributed to illitic clays, is little sensitive to the nature of the solution. Ruthenium-106 seems to move underground chiefly as a nitrosylruthenium hydroxide complex. This complex would be weakly sorbed on soil colloids by London--Van der Waals forces

  18. Stages of weathering mantle formation from carbonate rocks in the light of rare earth elements (REE) and Sr-Nd-Pb isotopes

    Science.gov (United States)

    Hissler, Christophe; Stille, Peter

    2015-04-01

    Weathering mantles are widespread and include lateritic, sandy and kaolinite-rich saprolites and residuals of partially dissolved rocks. These old regolith systems have a complex history of formation and may present a polycyclic evolution due to successive geological and pedogenetic processes that affected the profile. Until now, only few studies highlighted the unusual high content of associated trace elements in weathering mantles originating from carbonate rocks, which have been poorly studied, compared to those developing on magmatic bedrocks. For instance, these enrichments can be up to five times the content of the underlying carbonate rocks. However, these studies also showed that the carbonate bedrock content only partially explains the soil enrichment for all the considered major and trace elements. Up to now, neither soil, nor saprolite formation has to our knowledge been geochemically elucidated. Therefore, the aim of this study was to examine more closely the soil forming dynamics and the relationship of the chemical soil composition to potential sources. REE distribution patterns and Sr-Nd-Pb isotope ratios have been used because they are particularly well suited to identify trace element migration, to recognize origin and mixing processes and, in addition, to decipher possible anthropogenic and/or "natural" atmosphere-derived contributions to the soil. Moreover, leaching experiments have been applied to identify mobile phases in the soil system and to yield information on the stability of trace elements and especially on their behaviour in these Fe-enriched carbonate systems. All these geochemical informations indicate that the cambisol developing on such a typical weathering mantle ("terra fusca") has been formed through weathering of a condensed Bajocian limestone-marl facies. This facies shows compared to average world carbonates important trace element enrichments. Their trace element distribution patterns are similar to those of the soil

  19. Isotopic constraints on contamination processes in the Tonian Goiás Stratiform Complex

    Science.gov (United States)

    Giovanardi, Tommaso; Mazzucchelli, Maurizio; Lugli, Federico; Girardi, Vicente A. V.; Correia, Ciro T.; Tassinari, Colombo C. G.; Cipriani, Anna

    2018-06-01

    The Tonian Goiás Stratiform Complex (TGSC, Goiás, central Brazil), is one of the largest mafic-ultramafic layered complexes in the world, emplaced during the geotectonic events that led to the Gondwana accretion. In this study, we present trace elements and in-situ U/Pb-Lu-Hf analyses of zircons and 87Sr/86Sr ratios of plagioclases from anorthosites and gabbros of the TGSC. Although formed by three isolated bodies (Cana Brava, Niquelândia and Barro Alto), and characterized by a Lower and Upper Sequence (LS and US), our new U/Pb zircon data confirm recent geochemical, geochronological, and structural evidences that the TGSC has originated from a single intrusive body in the Neoproterozoic. New Hf and Sr isotope ratios construe a complex contamination history for the TGSC, with different geochemical signatures in the two sequences. The low Hf and high Sr isotope ratios of the Lower Sequence (εHf(t) from -4.2 down to -27.5; 87Sr/86Sr = 0.706605-0.729226), suggest the presence of a crustal component and are consistent with contamination from meta-pelitic and calc-silicate rocks found as xenoliths within the Sequence. The more radiogenic Hf isotope ratios and low Sr isotope composition of the Upper Sequence (εHf(t) from 11.3 down to -8.4; 87Sr/86Sr = 0.702368-0.702452), suggest a contamination from mantle-derived metabasalts in agreement with the occurrences of amphibolite xenoliths in the US stratigraphy. The differential contamination of the two sequences is explained by the intrusion of the TGSC in a stratified crust dominated by metasedimentary rocks in its deeper part and metavolcanics at shallower levels. Moreover, the differential thermal gradient in the two crystallizing sequences might have contributed to the preservation and recrystallization of inherited zircon grains in the US and total dissolution or magmatic overgrowth of the LS zircons via melt/rock reaction processes.

  20. Isotopic-geochemical investigation of Vitosh pluton (Bulgaria)

    International Nuclear Information System (INIS)

    Amelin, Yu.V.; Drubetskoj, E.R.; Monchev, N.B.; Nejmark, L.A.; Ovchinnikova, G.V.; Levskij, L.K.

    1989-01-01

    A set of isotope-geochronological (Rb-Sr, K-Ar, uranium fission tracks) and isotope-geochemical (Sr, Pb, Nd, He) methods was used to establish genesis and age of multi-phase Vitosh pluton. The investigation results have shown that primary magma from which pluton rocks were formed is generated at the level of high mantle - low crust. Insignificant difference in time of implantation and crystallization between variuos pluton phases is established. In the interval 84-79 millions of years the velocity of rock cooling and the velocity of pluton lift to the surface were estimated. In the interval 79-0 millions of years these velocities decrease essentially. After formation the rocks were not subjected to additional heat affects

  1. Generator coordinate method for triaxial quadrupole collective dynamics in strontium isotopes

    International Nuclear Information System (INIS)

    Bonche, P.; Dobaczewski, J.; Flocard, H.; Heenen, P.H.

    1991-01-01

    We discuss the algebraic structure of the generator coordinate method for triaxial quadrupole collective motion. The collective solutions are classified according to the representations of the permutation group of the intrinsic axes. Our method amounts to an approximate angular momentum projection. We apply it to a study of the spherical to deformed shape transition in light even strontium isotopes 78-88 Sr. We find that triaxial configurations play a significant role in explaining the structure of the transitional isotopes 80-82 Sr

  2. Neodymium and strontium isotope study of ophiolite and orogenic lherzolite petrogenesis

    International Nuclear Information System (INIS)

    Richard, P.; Allegre, C.J.; Paris-7 Univ., 75

    1980-01-01

    Neodymium isotopic analyses have been measured on nine ophiolites and four orogenic lherzolites. Epsilonsub(Nd) varies from +12 to +3 in the ophiolites and from +18 to +2 in the orogenic lherzolites. The majority of the analyses plot on a epsilonsub(Nd)-epsilonsub(Sr) correlation line as defined by Nd and Sr isotopic analyses of oceanic basalts. However, certain ophiolitic and lherzolitic samples exhibit high 87 Sr/ 86 Sr ratios and as such lie to the right of the correlation line towards seawater compositions. From these data one can postulate several origins for ophiolites including that of mid-ocean ridges and ocean islands. If the orogenic lherzolites are interpreted as representative of the mantle occurring below active ridges a more complex model is required involving mantle heterogeneity and multi-episodic chemical fractionation starting prior to 2 Ga ago. (orig.)

  3. Isotope and ion selectivity in reverse osmosis desalination: geochemical tracers for man-made freshwater.

    Science.gov (United States)

    Kloppmann, Wolfram; Vengosh, Avner; Guerrot, Catherine; Millot, Romain; Pankratov, Irena

    2008-07-01

    A systematic measurement of ions and 2H/1H, 7Li/6Li, 11B/10B, 18O/ 16O, and 87Sr/86Sr isotopes in feed-waters, permeates, and brines from commercial reverse osmosis (RO) desalination plants in Israel (Ashkelon, Eilat, and Nitzana) and Cyprus (Larnaca) reveals distinctive geochemical and isotopic fingerprints of fresh water generated from desalination of seawater (SWRO) and brackish water (BWRO). The degree of isotope fractionation during the passage of water and solutes through the RO membranes depends on the medium (solvent-water vs. solutes), chemical speciation of the solutes, their charge, and their mass difference. O, H, and Sr isotopes are not fractionated during the RO process. 7Li is preferentially rejected in low pH RO, and B isotope fractionation depends on the pH conditions. Under low pH conditions, B isotopes are not significantly fractionated, whereas at high pH, RO permeates are enriched by 20 per thousand in 11B due to selective rejection of borate ion and preferential permeation of 11B-enriched boric acid through the membrane. The specific geochemical and isotopic fingerprints of SWRO provide a unique tool for tracing "man-made" fresh water as an emerging recharge component of natural water resources.

  4. A Rb-Sr geochronological study on Tatehira granodiorite, Oshima Peninsula, Southwest Hokkaido, Japan

    International Nuclear Information System (INIS)

    Iizumi, Shigeru; Kobayashi, Hideo; Toyoda, Minoru.

    1984-01-01

    It has been known that Tatehira granodiorite, a pluton which occurs sporadically in the southwest region of Hokkaido, is related with Kanoite formation. The radiometric age of this granodiorite still remains unknown. The Tatehira granodiorite intrudes into late Paleozoic or early Mesozoic Matsumae group, and is overlain by Miocene Usubetsu formation unconformably. It occurs as several separated small plutons. The samples for Rb-Sr analysis were collected from one of the plutons in southern part. The determination of the isochron age of rock-minerals and the initial Sr isotopic ratio of Tatehira granodiorite were carried out. This granodiorite is able to be classified into two phases, namely melanocratic (WRM) and leucocratic (WRL) phases. The samples of WRM and WRL were powdered and subjected to X-ray analysis. It was found that the chemical compositions were similar except slight differences in FeO + Fe 2 O 3 , CaO and K 2 O. The Sr isotopic ratio was determined with a MAT 261 mass spectrometer, and the results were analyzed statistically. The Rb and Sr concentrations and the Sr isotopic ratio of WRM, WRL, and PRF (plagio-clase rich fraction) and BRF (biotite rich fraction) separated from the WRL were determined, and the age of 102.5 +- 0.3 Ma and the initial ratio of 0.70538 +- 0.00001 were obtained. The ratio of Tatehira granodiorite is comparable to that of Okushiri Island. Comparing with the data obtained from other region, the granodiorites of Tatehira and Okushiri Island should be related with the granitoids of Abukuma granite province. (Ishimitsu, A.)

  5. Geochemistry of Late Mesozoic mafic dykes in western Fujian Province of China:Sr-Nd isotope and trace element constraints

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Bancun diabase dyke and the Bali hornblende gabbro dyke in western Fuiian Province were emplaced in the Early and Late Cretaceous periods,respectively;the former is designated to calc-alkaline series and the latter to K-high-calc-alkaline rock series.Both the dykes are characterized by such geochemical characteristics as high Al and Na2O>K2O.As for the Bancun dyke,A12O3=16.32%-17.54%and K2O/Na2O=0.65-0.77;as for the Bali dyke,A12O3=16.89%-17.81%and K2O,Na2O=O.93-O.99.Both the Bancun and Bali mafic dykes are relatively endched in LILE and LREE,but depleted in HSFE, displaying the geochemical characteristics of continental marginal arc,with high initial Sr isotopic ratios and low εNd values,The (87Sr/86Sr)i ratios of the Bancun diabase dyke are within the range of 0.708556-0.70903 and their εNd(t)values vary between-6.8 and-6.3;those of the Bali hornblende dyke are within the range of 0.708556-0.710746 and their εNd(t) values are -4.7--4.7,showing the characteristics of enriched mantle EM Ⅱ.The isotope and trace element data showed that the mafic dykes have not experienced obvious crustal contamination,and metasomatism caused by subduction fluids is the main factor leading to LILE and UREE enrichments.The enriched mantle is the source region for the mafic dykes,and mixing of subduction fluid metasomatized enriched mantle and EM Ⅱ-type mantle constituted the mantle source region of both the Bancun and Bali mafic dykes.Upwelling of the asthenosphere mantle provided sufficient heat energy for the generation of magmas.In accordance with the discrimination diagram of their tectonic settings as well as their trace element geochemical characteristics,it is considered that the dykes both at Bancun and Bali possess the characteristics of continental marginal arc,revealing the tectonic environment of formation of the mafic dykes,the continental dynamic background as an intraplate tensional belt in which the mafic dykes were emplaced.Meanwhile,it is also indicated

  6. Rb-Sr And Sm-Nd Ages, and Petrogenesis of Depleted Shergottite Northwest Africa 5990

    Science.gov (United States)

    Shih, C. Y.; Nyquist, L. E.; Reese, Y.; Irving, A. J.

    2011-01-01

    Northwest Africa (NWA) 5990 is a very fresh Martian meteorite recently found on Hamada du Draa, Morocco and was classified as an olivine-bearing diabasic igneous rock related to depleted shergottites [1]. The study of [1] also showed that NWA 5990 resembles QUE 94201 in chemical, textural and isotopic aspects, except QUE 94201 contains no olivine. The depleted shergottites are characterized by REE patterns that are highly depleted in LREE, older Sm-Nd ages of 327-575 Ma and highly LREE-depleted sources with Nd= +35+48 [2-7]. Age-dating these samples by Sm-Nd and Rb-Sr methods is very challenging because they have been strongly shocked and contain very low abundances of light rare earth elements (Sm and Nd), Rb and Sr. In addition, terrestrial contaminants which are commonly present in desert meteorites will compromise the equilibrium of isotopic systems. Since NWA 5990 is a very fresh meteorite, it probably has not been subject to significant desert weathering and thus is a good sample for isotopic studies. In this report, we present Rb-Sr and Sm-Nd isotopic results for NWA 5990, discuss the correlation of the determined ages with those of other depleted shergottites, especially QUE 94201, and discuss the petrogenesis of depleted shergottites.

  7. Radiogenic Isotopes in Weathering and Hydrology

    Science.gov (United States)

    Blum, J. D.; Erel, Y.

    2003-12-01

    as on the observation that radiogenic isotopes are sometimes preferentially released compared to nonradiogenic isotopes of the same element during acid leaching of rocks ( Hart and Tilton, 1966; Silver et al., 1984; Erel et al., 1991). A major finding of these investigations was that weathering often results in anomalously young Rb-Sr isochron ages, and discordant Pb-Pb ages. Rubidium is generally retained relative to strontium in whole-rock samples, and in some cases radiogenic strontium and lead are lost preferentially to common strontium and lead from weathered minerals.The most widely utilized of these isotopic systems is Rb-Sr, followed by U-Pb. The K-Ar system is not directly applicable to most studies of rock-water interaction, because argon is a noble gas, and upon release during mineral weathering mixes with atmospheric argon, limiting its usefulness as a tracer in most weathering applications. Argon and other noble gas isotopes have, however, found important applications in hydrology (see Chapter 5.15). Three other isotopic systems commonly used in geochronology and petrology include Sm-Nd, Lu-Hf, and Re-Os. These parent and daughter elements are in very low abundance and concentrated in trace mineral phases. Sm-Nd, Lu-Hf, and Re-Os have been used in a few weathering studies but have not been utilized extensively in investigations of weathering and hydrology.The decay of 87Rb to 87Sr has a half-life of 48.8 Gyr, and this radioactive decay results in natural variability in the 87Sr/86Sr ratio in rubidium-bearing minerals (e.g., Blum, 1995). The trace elements rubidium and strontium are geochemically similar to the major elements potassium and calcium, respectively. Therefore, minerals with high K/Ca ratios develop high 87Sr/86Sr ratios over geologic timescales. Once released into the hydrosphere, strontium retains its isotopic composition without significant fractionation by geochemical or biological processes, and is therefore a good tracer for sources and

  8. Activity ratios of {sup 137}Cs, {sup 90}Sr and {sup 239+240}Pu in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Bossew, P. [European Commission - DG Joint Research Centre, Institute for Environment and Sustainability (IES), I-21020 Ispra (Vatican City State, Holy See,) (Italy)], E-mail: peter.bossew@jrc.it; Lettner, H. [Institute of Physics and Biophysics, University of Salzburg, Hellbrunner Strasse 34, A-5020 Salzburg (Austria)], E-mail: herbert.lettner@sbg.ac.at; Hubmer, A.; Erlinger, C.; Gastberger, M. [Institute of Physics and Biophysics, University of Salzburg, Hellbrunner Strasse 34, A-5020 Salzburg (Austria)

    2007-09-15

    Both global and Chernobyl fallout have resulted in environmental contamination with radionuclides such as {sup 137}Cs, {sup 90}Sr and {sup 239+240}Pu. In environmental samples, {sup 137}Cs and {sup 239+240}Pu can be divided into the contributions of either source, if also the isotopes {sup 134}Cs and {sup 238}Pu are measurable, based on the known isotopic ratios in global and Chernobyl fallout. No analogous method is available for {sup 90}Sr. The activity ratios of Sr to Cs and Pu, respectively, are known for the actual fallout mainly from air filter measurements; but due to the high mobility of Sr in the environment, compared to Cs and Pu, these ratios generally do not hold for the inventory many years after deposition. In this paper we suggest a method to identify the mean contributions of global and Chernobyl fallout to total Sr in soil, sediment and cryoconite samples from Alpine and pre-Alpine regions of Austria, based on a statistical evaluation of Sr/Cs/Pu radionuclide activity ratios. Results are given for Sr:Cs, Sr:Pu and Cs:Pu ratios. Comparison with fallout data shows a strong depletion of Sr against Cs and Pu.

  9. Strontium isotope model of formation of Blatna granodiorite

    International Nuclear Information System (INIS)

    Bendl, J.; Vokurka, K.

    1989-01-01

    The Blatna granodiorite is the second most abundant rock type of the Central Bohemian pluton. It belongs to the tonalite group. The Rb-Sr isochrone was constructed from granodiorite and mixed aplopegmatite-granodiorite whole rock samples. The age of final Sr isotopic homogenisation was found to be 331±9 Ma and the initial ratio of 87 Sr/ 86 Sr 0.7072±0.0015. The solidification temperature of the granodiorite (Whitney -Stormer, 1977) is 550±50 degC and that of the aplopegmatite 460±50 degC. The average Sr concentration in granodiorite is 331 ppm, that of Rb is 186 ppm. Values of 170 and 14 were found for the ratios K/Rb and Srx10 3 /Ca, respectively. REE patterns reveal a crustal component overprint. Mass balance calculations based on Sr isotopes, its concentration and on the overall geochemistry of the pluton and of the Moldanubian rock show that magma might have been generated as a mixture of about 30-50% of mantle and of 50-70% of upper crust materials. A certain part of the mantle component was brought to the region in the form of volcanics. The precursors of the crustal component might have been represented by recycled previous volcanosedimentary material with complex crustal history. (author). 4 figs., 2 tabs., 13 refs

  10. Accurate masses of unstable rare earth isotopes by ISOLTRAP

    International Nuclear Information System (INIS)

    Beck, D.; Ames, F.; Audi, G.

    2000-05-01

    Direct mass measurements of neutron-deficient rare earth isotopes in the vicinity of 146 Gd were performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. This paper reports on the measurement of more than 40 isotopes of the elements Pr, Nd, Pm, Sm, Eu, Dy and Ho, that have been measured with a typical accuracy of δm ∼ 14 keV. An atomic mass evaluation has been performed taking into account other experimental mass values via a least-squares adjustment. The results of the adjustment are discussed. (orig.)

  11. Isotope analytics for the evaluation of the feeding influence on the isotope ratio in beef samples

    International Nuclear Information System (INIS)

    Herwig, Nadine

    2010-01-01

    Information about the origin of food and associated production systems has a high significance for food control. An extremely promising approach to obtain such information is the determination of isotope ratios of different elements. In this study the correlation of the isotope ratios C-13/C-12, N-15/N-14, Mg-25/Mg-24, and Sr-87/Sr-86 in bovine samples (milk and urine) and the corresponding isotope ratios in feed was investigated. It was shown that in the bovine samples all four isotope ratios correlate with the isotope composition of the feed. The isotope ratios of strontium and magnesium have the advantage that they directly reflect the isotope ratios of the ingested feed since there is no isotope fractionation in the bovine organism which is in contrast to the case of carbon and nitrogen isotope ratios. From the present feeding study it is evident, that a feed change leads to a significant change in the delta C-13 values in milk and urine within 10 days already. For the deltaN-15 values the feed change was only visible in the bovine urine after 49 days. Investigations of cows from two different regions (Berlin/Germany and Goestling/Austria) kept at different feeding regimes revealed no differences in the N-15/N-14 and Mg-26/Mg-24 isotope ratios. The strongest correlation between the isotope ratio of the bovine samples and the kind of ingested feed was observed for the carbon isotope ratio. With this ratio even smallest differences in the feed composition were traceable in the bovine samples. Since different regions usually coincide with different feeding regimes, carbon isotope ratios can be used to distinguish bovine samples from different regions if the delta C-13 values of the ingested feed are different. Furthermore, the determination of strontium isotope ratios revealed significant differences between bovine and feed samples of Berlin and Goestling due to the different geologic realities. Hence the carbon and strontium isotope ratios allow the best

  12. Results of Rb-Sr dating of metamorphic rocks of crystalline complexes of Male Karpaty Mts

    International Nuclear Information System (INIS)

    Bagdasaryan, G.P.; Gukasyan, P.Kh.; Cambel, B.; Veselsky, J.

    1983-01-01

    The paper follows up on a recently published paper on Rb-Sr isochrone dating of granitoid rocks of the Male Karpaty Mts. Data are given on comparative statistical analysis of isochrones obtained for the Bratislava and Modra massifs (isochrone of the latter is complemented with the analyses of two new samples) and the results of age determination of metasedimentary rocks of the Pezinok-Pernek zone and the Bratislava area by the Rb-Sr isochrone. Regression analysis shows that there is no statistically significant difference between the age of the Bratislava massif (347+-4 m.y.) and the Modra massif (326+-22 m.y.) and between their initial ratios 87 Sr/ 86 Sr (i.e., they are synchronous, having the same magma source) which makes it possible to calculate uniform value for age. Whole-rock samples of metamorphic and crystalline schists (gneisses) of the Male Karpaty Mts. also determine the isochrone corresponding to the age 387+-38 m.y. (2σ) and initial ratio ( 87 Sr/ 86 Sr)=0.7100+-0.00O8 (2σ). Rb-Sr isotope analyses of several pairs of biotite-crystalline schist (from which biotite was separated) point out that redistribution of Sr isotopes among the mineral phases of rocks takes place during the periplutonic metamorphism, while the whole-rock samples remain chemically closed systems. (author)

  13. Isotopic and Chemical Evidence for Primitive Aqueous Alteration in the Tagish Lake Meteorite

    Science.gov (United States)

    Sakuma, Keisuke; Hidaka, Hiroshi; Yoneda, Shigekazu

    2018-01-01

    Aqueous alteration is one of the primitive activities that occurred on meteorite parent bodies in the early solar system. The Tagish Lake meteorite is known to show an intense parent body aqueous alteration signature. In this study, quantitative analyses of the alkaline elements and isotopic analyses of Sr and Ba from acid leachates of TL (C2-ungrouped) were performed to investigate effects of aqueous alteration. The main purpose of this study is to search for isotopic evidence of extinct 135Cs from the Ba isotopic analyses in the chemical separates from the Tagish Lake meteorite. Barium isotopic data from the leachates show variable 135Ba isotopic anomalies (ε = ‑2.6 ∼ +3.6) which correlatewith 137Ba and 138Ba suggesting a heterogeneous distribution of s- and r-rich nucleosynthetic components in the early solar system. The 87Rb–87Sr and 135Cs–135Ba decay systems on TL in this study do not provide any chronological information. The disturbance of the TL chronometers is likely a reflection of the selective dissolution of Cs and Rb given the relatively higher mobility of Cs and Rb compared to Ba and Sr, respectively, during fluid mineral interactions.

  14. Sr-Nd-Pb isotopes of the post-paleozoic magmatism from eastern Paraguay

    International Nuclear Information System (INIS)

    Comin-Chiaramonti, P; Gasparon, M; Gomes, C.B; Antonini, P

    2001-01-01

    The Parana Angola-Namibia igneous province (PAN) is characterized by Early Cretaceous flood tholeiites and tholeiitic dyke swarms associated with alkaline rocks of Early and Late Cretaceous ages, respectively, and with scarce post-Mesozoic magmatic rocks (Comin-Chiaramonti et al., 1997; 1999; Marques et al., 1999). The Eastern Paraguay, at the westernmost side of the Parana Basin, is of special interest because: (1) it is located between two main cratonic blocks, i.e. the southernmost tip of the Amazon Craton, and the northermost exposure of the Rio de La Plata Craton; (2) it was the site of repeated Na-K-alkaline magmatism since Late-Permian-Triassic times (i.e.: 250-240 Ma, Na-alkaline; c. 145 Ma, K-alkaline; 128-126 Ma, K-alkaline; 120-90 Ma, Na-alkaline; 61-33 Ma, Na-alkaline; cf. Comin-Chiaramonti and Gomes, 1996; Comin-Chiaramonti et al., 1999), and of Early Cretaceous tholeiitic magmatism, both low- and high-Ti variants, L-Ti and H-Ti, respectively (133-131 Ma; cf. Marzoli et al., 1999); (3) the younger sodic magmatic rocks are closely associated in space to the potassic analogues (Comin- Chiaramonti et al., 1999). The paper aims discussing the most important Sr- Nd-Pb isotope features of the alkaline and tholeiitic magmas from Eastern Paraguay in comparison with the PAN analogues (au)

  15. Strontium isotope geochemistry of groundwater affected by human activities in Nandong underground river system, China

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yongjun, E-mail: jiangjyj@swu.edu.cn [School of Geographical Sciences, Southwest University, Chongqing 400715 (China)] [Institute of Karst Environment and Rock Desertification Rehabilitation, Chongqing 400715 (China)

    2011-03-15

    Research highlights: {yields} Spatio-temporal variations of Sr concentrations and Sr isotopic composition of groundwater were investigated in a karst underground river system. {yields} Agricultural fertilizers and sewage effluents significantly modified the natural Sr isotopic signature of karst groundwater. {yields} Sr in the carbonate aquifers was relatively non-radiogenic, with low Sr concentrations, while anthropogenic Sr correlated with agricultural fertilizers and sewage effluents was relatively radiogenic, with higher Sr concentrations. {yields} {sup 87}Sr/{sup 86}Sr ratios can provide key information for natural and anthropogenic sources in karst groundwater. - Abstract: The Nandong Underground River System (NURS) is located in a typical karst area dominated by agriculture in SE Yunnan Province, China. Groundwater plays an important role in the social and economical development in the area. The effects of human activities (agriculture and sewage effluents) on the Sr isotope geochemistry were investigated in the NURS. Seventy-two representative groundwater samples, which were collected from different aquifers (calcite and dolomite), under varying land-use types, both in summer and winter, showed significant spatial differences and slight seasonal variations in Sr concentrations and {sup 87}Sr/{sup 86}Sr ratios. Agricultural fertilizers and sewage effluents significantly modified the natural {sup 87}Sr/{sup 86}Sr ratios signature of groundwater that was otherwise dominated by water-rock interaction. Three major sources of Sr could be distinguished by {sup 87}Sr/{sup 86}Sr ratios and Sr concentrations in karst groundwater. Two sources of Sr are the Triassic calcite and dolomite aquifers, where waters have low Sr concentrations (0.1-0.2 mg/L) and low {sup 87}Sr/{sup 86}Sr ratios (0.7075-0.7080 and 0.7080-0.7100, respectively); the third source is anthropogenic Sr from agricultural fertilizers and sewage effluents with waters affected having radiogenic {sup 87

  16. Parental Sources of High-Alumina Alkaline Melts: Nd, Sr, Pb, and O Isotopic Evidence from the Devonian Kiya-Shaltyr Gabbro-Urtite Intrusion, South Siberia

    Science.gov (United States)

    Vrublevskii, V. V.; Gertner, I. F.; Chugaev, A. V.

    2018-04-01

    The isotope geochemistry (ɛNd( t) 4.8-5.4, 206Pb/204Pb in 18.05-18.36, 207Pb/204Pbin 15.53-15.57, 208Pb/204Pb in 37.59-37.83, 87Sr/86Sr( t) 0.7048-0.7057, δ18OSMOW 8-10.5‰) and trace element composition of the Kiya-Shaltyr gabbro-urtite pluton allow us to suggest a heterogeneous source and complex geodynamic settings of the Devonian alkali magmatism in the Kuznetsk Alatau. It is assumed that its evolution took place under conditions of partial mingling of matter of the depleted (PREMA) and enriched (EM) mantle with crustal contamination of the evolving melt. Such an interaction could have been a result of superposition of a mantle plume and an active margin (OIB and IAB components). In fold belts this led to the formation of hybrid high-alumina foidoite magmas.

  17. Paleoclimatic and paleoceanographic studies of estuarine and marine sediments using strontium isotopes

    International Nuclear Information System (INIS)

    Ingram, B.L.

    1992-01-01

    Strontium isotopic ratio ( 87 Sr/ 86 Sr) measurements in fossil carbonates and phosphates are used to evaluate paleoceanographic and paleoclimatic environments in Quaternary, Pliocene-Pleistocene, and mid-Cretaceous estuarine and marine sediments. The use of 87 Sr/ 86 Sr measurements as an estuarine paleosalinity and paleoclimatic indicator is developed and applied to San Francisco Bay. 87 Sr/ 86 Sr measurements of foraminifer and molluscan fossils contained in estuarine sediments of late Pleistocene (ca 115 to 125 ka) and late Holocene (4.5 ka) age show cyclic variations indicating that salinity fluctuated with periods of several hundred years, probably reflecting wet-dry cycles associated with fluctuations in solar irradiance caused by sunspot cycles. The average salinity in San Pablo and Richardson bays was significantly lower (by 6 to 8%) over much of the past 4.5 ka than at present, reflecting a combination of decreased freshwater inflow at present associated with water diversion and wetter climatic conditions prior to 2000 years ago. Salinity data are converted to river discharge using salinity-delta flow relations derived from historical records for San Francisco Bay. The data indicate that annual freshwater inflow was at least twice the modern pre-diversion average between 2.5 and 3.0 Ka; this time period is also identified as one of wetter climatic conditions by lake level and treeline records from the Sierra Nevada. Strontium isotopic measurements of marine carbonate and fish teeth to middle Cretaceous age are used to increase the resolution of the existing seawater Sr isotope versus time curve and to assess models for global oceanic anoxic events. The new data using fish teeth show less scatter and variability than previous data. Negative excursions in the 87 Sr/ 86 Sr ratio of 7-14 parts in 10 -5 during Aptian anoxic events suggest a link between increased submarine volcanism and oceanic anoxia

  18. Isotopic composition of carbon in dacitic gases from Usu volcano (Japan). Relationship between the 13C/12C ratio of volatiles and the 87Sr/86Sr ratio of silicates in arc volcanism

    International Nuclear Information System (INIS)

    Allard, Patrick

    1981-01-01

    CO 2 emitted at 568 deg C by the new dacitic intrusion in Usu volcano (Japan) has a 13 C/ 12 C ratio of -4.4 per mill vs PDB. Such a value, together with previous isotopic data from other volcanoes in Japan, Indonesia, Central America, Lesser Antilles and New Zealand, enhance that the carbon released by magmas in subduction zones is systematically 13 C-enriched with respect to the primary carbon from rift areas. Such a 13 C enrichment in volatiles is explained in terms of crustal contamination by sedimentary carbon, and can be sowewhat related to a simultaneous increase of 87 Sr in the magma [fr

  19. Accurate experimental determination of the isotope effects on the triple point temperature of water. I. Dependence on the "2H abundance

    International Nuclear Information System (INIS)

    Faghihi, V.; Aerts-Bijma, A.T.; Jansen, H.G.; Spriensma, J.J.; Meijer, H.A.J.; Peruzzi, A.; Geel, J. van

    2015-01-01

    Variation in the isotopic composition of water is one of the major contributors to uncertainty in the realization of the triple point of water (TPW). Although the dependence of the TPW on the isotopic composition of the water has been known for years, there is still a lack of a detailed and accurate experimental determination of the values for the correction constants. This paper is the first of two articles (Part I and Part II) that address quantification of isotope abundance effects on the triple point temperature of water. In this paper, we describe our experimental assessment of the "2H isotope effect. We manufactured five triple point cells with prepared water mixtures with a range of "2H isotopic abundances encompassing widely the natural abundance range, while the "1"8O and "1"7O isotopic abundance were kept approximately constant and the "1"8O - "1"7O ratio was close to the Meijer-Li relationship for natural waters. The selected range of "2H isotopic abundances led to cells that realised TPW temperatures between approximately -140 μK to + 2500 μK with respect to the TPW temperature as realized by VSMOW (Vienna Standard Mean Ocean Water). Our experiment led to determination of the value for the δ"2H correction parameter of A_2_H = 673 μK/(per thousand deviation of δ"2H from VSMOW) with a combined uncertainty of 4 μK (k = 1, or 1 s). (authors)

  20. Studies on Horizontal and Vertical Migration of 90Sr in Soil Systems

    International Nuclear Information System (INIS)

    Solecki, J.; Chibowski, S.

    2002-01-01

    Here are presented results of studies on vertical and horizontal migration of strontium 90 Sr isotope in soil systems of Bug river valleys. Mean radioactivity of strontium in these soils was 26.15 ± 22.2 Bq/kg. Atmospheric precipitation of strontium on this area was 0.35 kBq/m2/cm. Radioactivity in soil profiles ranged from 17 to 130 Bq/m2/cm and the isotope was detected even at 30 cm depth. Some tendency to vertical migration of strontium towards the river was noticed. Obtained results were compared with concentrations of calcium and strontium in the soil. Any clear influence of these elements on the migration of strontium 90 Sr was noticed. (author)

  1. High-precision isotopic characterization of USGS reference materials by TIMS and MC-ICP-MS

    Science.gov (United States)

    Weis, Dominique; Kieffer, Bruno; Maerschalk, Claude; Barling, Jane; de Jong, Jeroen; Williams, Gwen A.; Hanano, Diane; Pretorius, Wilma; Mattielli, Nadine; Scoates, James S.; Goolaerts, Arnaud; Friedman, Richard M.; Mahoney, J. Brian

    2006-08-01

    The Pacific Centre for Isotopic and Geochemical Research (PCIGR) at the University of British Columbia has undertaken a systematic analysis of the isotopic (Sr, Nd, and Pb) compositions and concentrations of a broad compositional range of U.S. Geological Survey (USGS) reference materials, including basalt (BCR-1, 2; BHVO-1, 2), andesite (AGV-1, 2), rhyolite (RGM-1, 2), syenite (STM-1, 2), granodiorite (GSP-2), and granite (G-2, 3). USGS rock reference materials are geochemically well characterized, but there is neither a systematic methodology nor a database for radiogenic isotopic compositions, even for the widely used BCR-1. This investigation represents the first comprehensive, systematic analysis of the isotopic composition and concentration of USGS reference materials and provides an important database for the isotopic community. In addition, the range of equipment at the PCIGR, including a Nu Instruments Plasma MC-ICP-MS, a Thermo Finnigan Triton TIMS, and a Thermo Finnigan Element2 HR-ICP-MS, permits an assessment and comparison of the precision and accuracy of isotopic analyses determined by both the TIMS and MC-ICP-MS methods (e.g., Nd isotopic compositions). For each of the reference materials, 5 to 10 complete replicate analyses provide coherent isotopic results, all with external precision below 30 ppm (2 SD) for Sr and Nd isotopic compositions (27 and 24 ppm for TIMS and MC-ICP-MS, respectively). Our results also show that the first- and second-generation USGS reference materials have homogeneous Sr and Nd isotopic compositions. Nd isotopic compositions by MC-ICP-MS and TIMS agree to within 15 ppm for all reference materials. Interlaboratory MC-ICP-MS comparisons show excellent agreement for Pb isotopic compositions; however, the reproducibility is not as good as for Sr and Nd. A careful, sequential leaching experiment of three first- and second-generation reference materials (BCR, BHVO, AGV) indicates that the heterogeneity in Pb isotopic compositions

  2. Rapid and Accurate Behavioral Health Diagnostic Screening: Initial Validation Study of a Web-Based, Self-Report Tool (the SAGE-SR).

    Science.gov (United States)

    Brodey, Benjamin; Purcell, Susan E; Rhea, Karen; Maier, Philip; First, Michael; Zweede, Lisa; Sinisterra, Manuela; Nunn, M Brad; Austin, Marie-Paule; Brodey, Inger S

    2018-03-23

    The Structured Clinical Interview for DSM (SCID) is considered the gold standard assessment for accurate, reliable psychiatric diagnoses; however, because of its length, complexity, and training required, the SCID is rarely used outside of research. This paper aims to describe the development and initial validation of a Web-based, self-report screening instrument (the Screening Assessment for Guiding Evaluation-Self-Report, SAGE-SR) based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and the SCID-5-Clinician Version (CV) intended to make accurate, broad-based behavioral health diagnostic screening more accessible within clinical care. First, study staff drafted approximately 1200 self-report items representing individual granular symptoms in the diagnostic criteria for the 8 primary SCID-CV modules. An expert panel iteratively reviewed, critiqued, and revised items. The resulting items were iteratively administered and revised through 3 rounds of cognitive interviewing with community mental health center participants. In the first 2 rounds, the SCID was also administered to participants to directly compare their Likert self-report and SCID responses. A second expert panel evaluated the final pool of items from cognitive interviewing and criteria in the DSM-5 to construct the SAGE-SR, a computerized adaptive instrument that uses branching logic from a screener section to administer appropriate follow-up questions to refine the differential diagnoses. The SAGE-SR was administered to healthy controls and outpatient mental health clinic clients to assess test duration and test-retest reliability. Cutoff scores for screening into follow-up diagnostic sections and criteria for inclusion of diagnoses in the differential diagnosis were evaluated. The expert panel reduced the initial 1200 test items to 664 items that panel members agreed collectively represented the SCID items from the 8 targeted modules and DSM criteria for the covered

  3. pH-Dependent isotope exchange and hydrogenation catalysed by water-soluble NiRu complexes as functional models for [NiFe]hydrogenases

    OpenAIRE

    Kure, Bunsho; Matsumoto, Takahiro; Ichikawa, Koji; Fukuzumi, Shunichi; Higuchi, Yoshiki; Yagi, Tatsuhiko; Ogo, Seiji

    2008-01-01

    The pH-dependent hydrogen isotope exchange reaction between gaseous isotopes and medium isotopes and hydrogenation of the carbonyl compounds have been investigated with water-soluble bis(mu-thiolate)(mu-hydride)NiRu complexes, Ni(II)(mu-SR)(2)(mu-H)Ru(II) {(mu-SR)(2) = N,N'-dimethyl-N,N'-bis(2-mercaptoethyl)-1,3-propanediamine}, as functional models for [NiFe]hydrogenases. In acidic media (at pH 4-6), the mu-H ligand of the Ni(II)(mu-SR)(2)(mu-H)Ru(II) complexes has H(+) properties, and the c...

  4. Effect of mycorrhizal infection on root uptake by pine seedlings and redistribution of three contrasting radio-isotopes: {sup 85}Sr, {sup 95m}Tc and {sup 137}Cs

    Energy Technology Data Exchange (ETDEWEB)

    Plassard, C.; Ladeyn, I.; Staunton, S. [Institut National de Recherches Agronomiques (INRA), UMR Rhizosphere and Symbiose 34 - Montpellier (France)

    2004-07-01

    Mycorrhizal infection is known to improve phosphate nutrition and water supply of higher plants. It has been reported to both increase the uptake of potentially toxic pollutant elements and to protect plants against toxic effects. Little is known about the effect of mycorrhizal infection on the dynamics of radioactive pollutants in soil-plant systems. The aim of this study was to compare the root uptake and root-shoot transfer of three radio-isotopes with contrasting chemical properties ({sup 85}Sr, {sup 95m}Tc and {sup 137}Cs) in mycorrhizal and control, non mycorrhizal plants. The plant studied was Pinus pinaster and the associated ecto-mycorrhizal fungus was Rhizopogon roseolus (strain R18-2). Plants were grown under anoxic conditions for 3 months then transferred to thin layers of autoclaved soil and allowed to grow for four months. After this period, the rhizotrons were dismantled, and plant tissue analysed. Biomass, nutrient content (K, P, N, Ca) and activities of each isotope in roots, shoots and stems were measured, and the degree of mycorrhizal infection assessed. The transfer factors decreased in the order Tc>Sr>Cs as expected from the degree of immobilisation by soil. No effect of mycorrhizal infection on root uptake was observed for Sr. Shoot activity concentration of Tc was decreased by mycorrhizal infection but root uptake correlated well with mycelial soil surface area. In contrast, Cs shoot activity was greater in mycorrhizal than control plants. The uptake and root to shoot distribution shall be discussed in relation to nutrient dynamics. (author)

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

    Science.gov (United States)

    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.

  6. Interrogating pollution sources in a mangrove food web using multiple stable isotopes.

    Science.gov (United States)

    Souza, Iara da C; Arrivabene, Hiulana P; Craig, Carol-Ann; Midwood, Andrew J; Thornton, Barry; Matsumoto, Silvia T; Elliott, Michael; Wunderlin, Daniel A; Monferrán, Magdalena V; Fernandes, Marisa N

    2018-06-01

    Anthropogenic activities including metal contamination create well-known problems in coastal mangrove ecosystems but understanding and linking specific pollution sources to distinct trophic levels within these environments is challenging. This study evaluated anthropogenic impacts on two contrasting mangrove food webs, by using stable isotopes (δ 13 C, δ 15 N, 87 Sr/ 86 Sr, 206 Pb/ 207 Pb and 208 Pb/ 207 Pb) measured in sediments, mangrove trees (Rhizophora mangle, Laguncularia racemosa, Avicennia schaueriana), plankton, shrimps (Macrobranchium sp.), crabs (Aratus sp.), oysters (Crassostrea rhizophorae) and fish (Centropomus parallelus) from both areas. Strontium and Pb isotopes were also analysed in water and atmospheric particulate matter (PM). δ 15 N indicated that crab, shrimp and oyster are at intermediate levels within the local food web and fish, in this case C. parallelus, was confirmed at the highest trophic level. δ 15 N also indicates different anthropogenic pressures between both estuaries; Vitória Bay, close to intensive human activities, showed higher δ 15 N across the food web, apparently influenced by sewage. The ratio 87 Sr/ 86 Sr showed the primary influence of marine water throughout the entire food web. Pb isotope ratios suggest that PM is primarily influenced by metallurgical activities, with some secondary influence on mangrove plants and crabs sampled in the area adjacent to the smelting works. To our knowledge, this is the first demonstration of the effect of anthropogenic pollution (probable sewage pollution) on the isotopic fingerprint of estuarine-mangrove systems located close to a city compared to less impacted estuarine mangroves. The influence of industrial metallurgical activity detected using Pb isotopic analysis of PM and mangrove plants close to such an impacted area is also notable and illustrates the value of isotopic analysis in tracing the impact and species affected by atmospheric pollution. Copyright © 2018 Elsevier B

  7. OIB signatures in basin-related lithosphere-derived alkaline basalts from the Batain basin (Oman) - Constraints from 40Ar/39Ar ages and Nd-Sr-Pb-Hf isotopes

    Science.gov (United States)

    Witte, M.; Jung, S.; Pfänder, J. A.; Romer, R. L.; Mayer, B.; Garbe-Schönberg, D.

    2017-08-01

    Tertiary rift-related intraplate basanites from the Batain basin of northeastern Oman have low SiO2 ( 9.73 wt.%) and moderate to high Cr and Ni contents (Cr > 261 ppm, Ni > 181 ppm), representing near primary magmas that have undergone fractionation of mainly olivine and magnetite. Rare earth element systematics and p-T estimates suggest that the alkaline rocks are generated by different degrees of partial melting (4-13%) of a spinel-peridotite lithospheric mantle containing residual amphibole. The alkaline rocks show restricted variations of 87Sr/86Sr and 143Nd/144Nd ranging from 0.70340 to 0.70405 and 0.51275 to 0.51284, respectively. Variations in Pb isotopes (206Pb/204Pb: 18.59-18.82, 207Pb/204Pb: 15.54-15.56, 208Pb/204Pb: 38.65-38.98) of the alkaline rocks fall in the range of most OIB. Trace element constraints together with Sr-Nd-Pb isotope composition indicate that assimilation through crustal material did not affect the lavas. Instead, trace element variations can be explained by melting of a lithospheric mantle source that was metasomatized by an OIB-type magma that was accumulated at the base of the lithosphere sometimes in the past. Although only an area of less than 1000 km2 was sampled, magmatic activity lasted for about 5.5 Ma with a virtually continuous activity from 40.7 ± 0.7 to 35.3 ± 0.6 Ma. During this period magma composition was nearly constant, i.e. the degree of melting and the nature of the tapped source did not change significantly over time.

  8. mu SR in Organic and Free Radical Chemistry

    CERN Multimedia

    2002-01-01

    Experiment SC82 was begun as a simple attempt to substitute positive muons into polymer molecules, and thereby to use the @mSR technique to study the mechanical relaxation of the different molecular groups. \\\\ \\\\ The experiment has since developed in several directions and has produced a wealth of information on the properties of muonic molecules, and adequately demonstrated the potential of @mSR as applied to molecular physics and chemistry. Physics aspects are now covered by a new experiment code SC95.\\\\ \\\\ The present experiment includes studies where the position occupied by the muon in the molecule (or crystal lattice) is readily established and the @mSR signal is exploited to reveal the intrinsic properties of the material. In this respect the @mSR techniques may be regarded simply as an experimental tool to probe the molecular behaviour of a chemical system. \\\\ \\\\ Two main classes of application include the measurement of isotope effects, where differences between muonic and corresponding photonic radi...

  9. Accurate experimental determination of the isotope effects on the triple point temperature of water. I. Dependence on the 2H abundance

    Science.gov (United States)

    Faghihi, V.; Peruzzi, A.; Aerts-Bijma, A. T.; Jansen, H. G.; Spriensma, J. J.; van Geel, J.; Meijer, H. A. J.

    2015-12-01

    Variation in the isotopic composition of water is one of the major contributors to uncertainty in the realization of the triple point of water (TPW). Although the dependence of the TPW on the isotopic composition of the water has been known for years, there is still a lack of a detailed and accurate experimental determination of the values for the correction constants. This paper is the first of two articles (Part I and Part II) that address quantification of isotope abundance effects on the triple point temperature of water. In this paper, we describe our experimental assessment of the 2H isotope effect. We manufactured five triple point cells with prepared water mixtures with a range of 2H isotopic abundances encompassing widely the natural abundance range, while the 18O and 17O isotopic abundance were kept approximately constant and the 18O  -  17O ratio was close to the Meijer-Li relationship for natural waters. The selected range of 2H isotopic abundances led to cells that realised TPW temperatures between approximately  -140 μK to  +2500 μK with respect to the TPW temperature as realized by VSMOW (Vienna Standard Mean Ocean Water). Our experiment led to determination of the value for the δ2H correction parameter of A2H  =  673 μK / (‰ deviation of δ2H from VSMOW) with a combined uncertainty of 4 μK (k  =  1, or 1σ).

  10. 87Sr/86Sr and 143Nd/144Nd for disentangling anthropogenic and natural REE contributions in river water during flood events.

    Science.gov (United States)

    Hissler, Christophe; Stille, Peter; Pfister, Laurent

    2017-04-01

    The sustainable management of water resources is one of the greatest challenges of the 21st century. Water is a vital resource that is increasingly put under pressure from multiple perspectives. While the global population is on the rise, socio-economic development makes equally rapid progress - eventually compromising access to clean water bodies. Multiple pollution sources constitute an immediate threat to aquatic ecosystems and are likely to cause long lasting contaminations of water bodies that are critical for drinking and/or irrigation water production. There is a pressing need for an adequate quantification of anthropogenic impacts on the critical zone of river basins and the identification of the temporal dynamics of these impacts. As an example, despite the work done to assess the environmental impact of REE pollutions in larger river systems, we are still lacking information on the dynamics of these anthropogenic compounds in relation to rapid hydrological changes. Filling these knowledge gaps is a pre-requisite for the design and implementation of sustainable water resources management strategies. In order to better constrain the relative contributions of both anthropogenic and geogenic trace element sources we propose using a multitracer approach combining elemental and 87Sr/86Sr, 143Nd/144Nd, and 206Pb/207Pb isotopic ratios. The use of these three separate isotopic systems together with REE concentrations is new in the field of anthropogenic source identification in river systems. We observed enrichments in Anthropogenic Rare Earth Elements (AREE) for dissolved Gd and suspended Nd loads of river water. With increasing discharge, AREE anomalies progressively disappeared and gave way to the geogenic chemical signature of the basin in both dissolved and suspended loads. The isotopic data confirm these observations and shed new light on the trace elements sources. On the one hand, dissolved loads have peculiar isotopic characteristics and carry mainly

  11. Constraints on Ca/Sr as a Proxy for Calcium in Forest Ecosystems

    Science.gov (United States)

    Hoff, C. J.; Hobbie, E. A.; Hallett, R.; Colpaert, J.; Bryce, J. G.

    2004-05-01

    Calcium is a key plant nutrient and important base cation in ecosystems. Our current efforts to quantify Ca cycling in ecosystems rely on indirect proxies, e.g., Ca/Sr or Sr isotopic systems (1). An important assumption in these applications is that the elemental ratio of calcium to strontium faithfully represents calcium cycling and that little fractionation occurs through biogeochemical and physiological processes. However, several researchers have reported variations in Ca/Sr, e.g. among different tree tissues (2) and during weathering processes (3), raising doubts about the suitability of the proxy. To address the question of reliability, we measured Ca/Sr values in a culture study in which Scots pines were grown at low or high nutrient supply rates (3% per day or 5% per day). Because mycorrhizal fungi are intimately involved in plant nutrient supply, plants were also grown either uncolonized or colonized with one of two different species of mycorrhizal fungi (Suillus luteus and Thelephora terrestris). Our preliminary results indicate that Ca/Sr values differ between high and low nutrient treatments, root and foliage, and mycorrhizal treatments. In individual seedlings, roots have lower Ca/Sr than foliage by absolute factors of 2-5. The magnitude of the effect is apparently determined by a combination of environmental factors including both the nutrient and mycorrhizal treatments. These results indicate that Ca and Sr are partitioned differently between nutrient and mycorrhizal treatments and between plant fractions despite the common nutrient broth and substrate. Thus, Ca/Sr values alone are not reliable tracers of Ca within an ecosystem because of partitioning of Ca and Sr during nutrient transport within the plant-mycorrhizal system. We are presently refining analytical techniques and conducting leachate experiments to improve the quantification of this Ca/Sr fractionation. We are also exploring the use of isotopic tracers to study calcium biogeochemical

  12. Hydrogeochemistry and isotope geochemistry of Velenje Basin groundwater

    Directory of Open Access Journals (Sweden)

    Tjaša Kanduč

    2016-08-01

    Full Text Available The geochemical and isotopic composition of groundwater in the Velenje Basin, Slovenia, was investigated between the years 2014 to 2015 to identify the geochemical processes in the major aquifers (Pliocene and Triassic and the water–rock interactions. Thirty-eight samples of groundwater were taken from the aquifers, 19 in the mine and 19 from the surface. Groundwater in the Triassic aquifer is dominated by HCO3–, Ca2+ and Mg2+ with δ13C DIC values in the range from -19.3 to -2.8 ‰, indicating degradation of soil organic matter and dissolution of carbonate minerals. In contrast, groundwater in the Pliocene aquifers is enriched in Mg2+, Na+, Ca2+, K+, and Si, and has high alkalinity, with δ13CDIC values in the range of -14.4 to +4.6 ‰. Based on the δ13CDIC values in all the aquifers (Pliocene and Triassic, both processes inflence the dissolution of carbonate minerals and dissolution of organic matter and in the Pliocene aquifers, methanogenesis as well. Based on Principal Component Analysis (PCA, and on geochemical and isotopic data we conclude that the following types of groundwater in Velenje Basin are present: Triassic aquifers with higher pH and lower conductivity and chloride, Pliocene, Pliocene 1 and Pliocene 2 aquifers with lower pH and higher conductivity and chloride contents, and Pliocene 3 and Pliocene 2, 3 aquifers with the highest pH values and lowest conductivities and chloride contents. 87Sr/86Sr tracer was used for the fist time in Slovenia to determine geochemical processes (dissolution of silicate versus carbonate fraction in Velenje Basin groundwater of different aquifers dewatering Pliocene and Triassic strata. 87Sr/86Sr values range from 0.70820 to 0.71056 in groundwater of Pliocene aquifers and from 0.70808 to 0.70910 in groundwater of the Triassic aquifer. This indicates that dissolution of the carbonate fraction prevails in both aquifers, while in Pliocene aquifers, an additional silicate weathering prevails with

  13. The initial 87Sr/86Sr ratios of the Kirwan Volcanics of Dronning Maud Land: Comparison with the Kirkpatrick Basalt, Transantarctic Mountains

    International Nuclear Information System (INIS)

    Faure, G.; Bowman, J.R.; Elliot, D.H.

    1979-01-01

    A series of lava flows from Mountain B (6 0 13.9'W, 74 0 06.9'S) of the Kirwan Escarpment in Dronning Maud Land, Antarctica, is composed of tholeiite basalts of Jurassic age. Their chemical compositions are similar to those of Jurassic basalts elsewhere in Dronning Maud Land but differ from those of the Kirkpatrick Basalt of the Transantarctic Mountains. The basalts on Mountain B contain 50.39% SiO 2 , 9.7 ppm Rb, 174.4 ppm Sr, have a Rb/Sr ratio of 0.057, and a K/Rb ratio of 417. Their average initial 87 Sr/ 86 Sr ratio is 0.7044 +- 0.0010 (1sigma) which suggests that the magma from which they formed could have been derived from the upper mantle without extensive contamination with 87 Sr and other elements. These results confirm earlier suggestions that the Jurassic basalts of Dronning Maud Land differ significantly from the Kirkpatrick Basalt and the Ferrar Dolerite of the Transantarctic Mountains. These differences in chemical and Sr-isotopic composition may be related to tectonic activity and magma formation during the break-up of Gondwanaland. (Auth.)

  14. Isotope shift of the 590-cm-1 Raman feature in underdoped Bi2Sr2CaCu2O8+δ

    Science.gov (United States)

    Hewitt, K. C.; Wang, N. L.; Irwin, J. C.; Pooke, D. M.; Pantoja, A. E.; Trodahl, H. J.

    1999-10-01

    Raman-scattering studies have been performed on underdoped Bi2Sr2CaCu2O8+δ. In single crystals underdoped by oxygen removal, a 590-cm-1 peak is observed in the B1g spectrum. The feature is observed to soften in frequency by 3.8% with isotopic exchange of 16O by 18O. In contrast, the 590-cm-1 peak is not observed in crystals underdoped by Y substitution which suggests that it is a vibrational mode activated by oxygen deficency. We have also found that underdoping leads to a depletion of low-energy spectral weight from regions of the Fermi surface located near the Brillouin-zone axes.

  15. The effect of natural weathering on the chemical and isotopic composition of biotites

    International Nuclear Information System (INIS)

    Clauer, N.; Bonnot-Courtois, C.

    1982-01-01

    The effect of progressive natural weathering on the isotopic (Rb-Sr, K-Ar, deltaD, delta 18 O) and chemical (REE, H 2 O + ) compositions of biotite has been studied on a suite of migmatitic biotites from the Chad Republic. During the early stages of weathering the Rb-Sr system is strongly affected, the hydrogen and oxygen isotope compositions change markedly, the minerals are depleted in light REE, the water content increases by a factor of two, and the K-Ar system is relatively little disturbed. During intensive weathering the K-Ar system is more strongly disturbed than the Rb-Sr system. Most of the isotopic and chemical modifications take place under nonequilibrium conditions and occur before newly formed kaolinite and/or smectite can be detected. These observations suggest that (a) 'protominerals' may form within the biotite structure during the initial period of weathering, and (b) only when chemical equilibrium is approached in the weathering profile are new minerals able to form. (author)

  16. Tracing changes in mantle and crustal influences in individual cone-building stages at Mt. Shasta using U-Th and Sr isotopes

    Science.gov (United States)

    Wende, Allison M.; Johnson, Clark M.; Beard, Brian L.

    2015-10-01

    230Th-excess is rare in most arc lavas, but common in the Cascades, yet the origin of such excesses remains unclear. At Mt. Shasta, age-corrected (230Th/232Th) and (238U/232Th) activity ratios range from 1.108 to 1.290 and from 0.987 to 1.309 (27.3% 230Th-excess to 6.1% 238U-excess), respectively. Although small degrees of zircon crystallization (ancestral cone (Sand Flat) was followed by four cone-building stages, three of which lie in the age range of U-series geochronology. Lavas within individual eruptive stages have relatively constant (230Th/232Th)0 ratios that are interpreted to reflect specific mixtures of mantle (m) and lower crustal (lc) melts that are characteristic of a specific stage (Mm:lc). High (230Th/232Th)0 ratios identify higher proportions of lower crust in the Misery Hill stage (Mm:lc = ∼ 85 : 15), whereas low (230Th/232Th)0 ratios reflect the more mantle-like composition of the Shastina lavas (Mm:lc = ∼ 95 : 5); in the case of Shastina lavas, very low 87Sr/86Sr ratios, down to 0.7029, support a substantial mantle contribution. Changes in (230Th/232Th)0 ratios correlate with eruptive volume, where the most voluminous stage (Misery Hill) is inferred to have the largest proportion of crustal melt and highest (230Th/232Th)0 ratios. Variable (230Th/238U)0 ratios within, and between, eruptive groups likely reflect a combination of residence time in the lower crust and differential assimilation of bulk, non-garnet-bearing crust that had (230Th/238U) = 1. The volume-(230Th/232Th)0 relations are accompanied by correlations with 87Sr/86Sr ratios, where the most radiogenic Sr is associated with the largest eruptive volumes, indicating that the largest magmatic episodes produced the largest amount of lower crustal interaction. The new U-Th and Sr isotope measurements of this study, along with U-series data for other Cascade centers suggest that interaction with the lower crust exerts greater control on Cascade magma chemistry than previously

  17. Isotopic and chemical investigations on Angra dos Reis

    International Nuclear Information System (INIS)

    Wasserburg, G.J.; Tera, F.; Papanastassiou, D.A.; Huneke, J.C.

    1977-01-01

    Extensive isotopic studies of Pb, Sr and Xe and chemical abundance measurements of K, Rb, Sr, Ba, Nd, Sm, U and Th for total meteorite and mineral separates of the Angra dos Reis achondrite are reported on. U-Pb, Th-Pb and Pb-Pb ages are concordant at 4.54 AE for the total meteorite and for high-purity whitlockite in Angra dos Reis. This establishes Angra dos Reis as an early planetary differentiate which has not been disturbed for these systems since 4.54 AE ago. Measured 87 Sr/ 86 Sr in pyroxene and whitlockite for Angra dos Reis (ADOR) are distinctly below BABI by two parts in 10 4 and only one part in 10 4 above the lowest 87 Sr/ 86 Sr (ALL) measured in an Allende inclusion. The difference in ADOR-ALL corresponds to an interval of condensation in the solar nebula of approximately 3 m.y. If 26 Al was the heat source for the magmatism on the parent planets of Angra dos Reis and the basaltic achondrites (BABI) then the relatively large difference in 87 Sr/ 86 Sr, BABI - ALL, must be the result of planetary evolution rather than condensation over approximately 10 m.y. Xe isotopic measurements confirm the presence of large amounts of 244 Pu-produced fission Xe and show that 244 Pu was enriched in the whitlockite relative to the pyroxene by a factor of approximately 18. Chemical element enrichment factors between the whitlockite and the fassaitic pyroxene in Angra dos Reis are presented. The enrichment factors demonstrate close analogy between the rare earth elements and their actinide analogs. The enrichment factor for Pu is intermediate to the enrichment factors of Nd and Sm. (Auth.)

  18. Accumulation of 90Sr in sheep bones from different regions of Turkey

    International Nuclear Information System (INIS)

    Acar, R.; Okay, G.; Akman, S.

    1989-01-01

    The accumulation of 90 Sr in front leg bones of sheep which were 1-6 years old and originated from different regions of Turkey, was investigated. It was shown that 90 Sr activity strongly depends on the age of the sheep as well as on their origin. Since 90 Sr is produced during the fissioning process of uranium isotopes in nuclear reactions, the effect of radiation due to nuclear bomb experiments, nuclear reactor accidents or other radioactive pollutants in different regions of Turkey can be concluded from results obtained. (author) 6 refs.; 3 figs.; 9 tabs

  19. Geochemical and isotopic characteristics and magma sources of the early Cretaceous trachybasalts of the Goby-Altai rift zone: an example of grabens in the Arts-Bogdo range

    International Nuclear Information System (INIS)

    Samojlov, V.S.; Yarmolyuk, V.V.; Kovalenko, V.I.; Ivanov, V.G.; Pakhol'chenko, Yu.A.

    1998-01-01

    Geochemical and isotopic-geochemical characteristics of the basalts of Early Cretaceous (Hoby-Altai rift zone; Arts-Bogdo region, Mongolia). Atomic absorption spectroscopy, X-ray fluorescence spectroscopy, photometry, mass spectroscopy and other methods were used. Mantle nature of the basalt geochemical specificity is shown as well as their initial melts. Data on the rubidium-strontium isotopic composition of Neocomian basalts are the following ones: 87 Sr/ 86 Sr 87 Sr/ 86 Sr > 0.707 and Rb/Sr > 0.06 [ru

  20. Strontium isotopic geochemistry of intrusive rocks, Puerto Rico, Greater Antilles

    International Nuclear Information System (INIS)

    Jones, L.M.; Kesler, S.E.

    1980-01-01

    The strontium isotope geochemistry is given for three Puerto Rican intrusive rocks: the granodioritic Morovis and San Lorenzo plutons and the Rio Blanco stock of quartz dioritic composition. The average calculated initial 87 Sr/ 86 Sr ratios are 0.70370, 0.70355 and 0.70408, respectively. In addition, the San Lorenzo data establish a whole-rock isochron of 71 +- 2 m.y., which agrees with the previously reported K-Ar age of 73 m.y. Similarity of most of the intrusive rocks in the Greater Antilles with respect to their strontium isotopic geochemistry regardless of their major element composition indicates that intrusive magmas with a wide range of composition can be derived from a single source material. The most likely source material, in view of the available isotopic data, is the mantle wedge overlying the subduction zone. (orig.)

  1. Isotopic approach to the provenance study of artifacts

    International Nuclear Information System (INIS)

    Mabuchi, Hisao

    1994-01-01

    Isotopic abundance ratios, which are proved to be generally constant, are known to vary, for certain elements, from one place to another. Light elements, such as hydrogen, lithium, boron, carbon, nitrogen, oxygen and sulfur, show measurable variations of their isotope ratios due to isotopic fractionation which takes place during geochemical or biochemical processes. Isotope ratios of strontium and lead vary due to the decay of long-lived radioactive nuclides 87 Rb and 238 U- 235 U- 232 Th, respectively. Such isotopic anomalies can be applicable to provenance studies of archaeological objects. Thus, 13 C/ 12 C, 18 O/ 16 O, or 87 Sr/ 86 Sr were used to examine the authenticity of Greek marble statues. Also, lead isotope ratios have been u