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Sample records for 32s 33s 34s

  1. Determination of the sulfur isotope ratio in carbonyl sulfide using gas chromatography/isotope ratio mass spectrometry on fragment ions 32S+, 33S+, and 34S+.

    PubMed

    Hattori, Shohei; Toyoda, Akari; Toyoda, Sakae; Ishino, Sakiko; Ueno, Yuichiro; Yoshida, Naohiro

    2015-01-01

    Little is known about the sulfur isotopic composition of carbonyl sulfide (OCS), the most abundant atmospheric sulfur species. We present a promising new analytical method for measuring the stable sulfur isotopic compositions (δ(33)S, δ(34)S, and Δ(33)S) of OCS using nanomole level samples. The direct isotopic analytical technique consists of two parts: a concentration line and online gas chromatography-isotope ratio mass spectrometry (GC-IRMS) using fragmentation ions (32)S(+), (33)S(+), and (34)S(+). The current levels of measurement precision for OCS samples greater than 8 nmol are 0.42‰, 0.62‰, and 0.23‰ for δ(33)S, δ(34)S, and Δ(33)S, respectively. These δ and Δ values show a slight dependence on the amount of injected OCS for volumes smaller than 8 nmol. The isotope values obtained from the GC-IRMS method were calibrated against those measured by a conventional SF6 method. We report the first measurement of the sulfur isotopic composition of OCS in air collected at Kawasaki, Kanagawa, Japan. The δ(34)S value obtained for OCS (4.9 ± 0.3‰) was lower than the previous estimate of 11‰. When the δ(34)S value for OCS from the atmospheric sample is postulated as the global signal, this finding, coupled with isotopic fractionation for OCS sink reactions in the stratosphere, explains the reported δ(34)S for background stratospheric sulfate. This suggests that OCS is a potentially important source for background (nonepisodic or nonvolcanic) stratospheric sulfate aerosols. PMID:25439590

  2. 34S/32S fractionation in sulfur cycles catalyzed by anaerobic bacteria.

    PubMed Central

    Fry, B; Gest, H; Hayes, J M

    1988-01-01

    Stable isotopic distributions in the sulfur cycle were studied with pure and mixed cultures of the anaerobic bacteria, Chlorobium vibrioforme and Desulfovibrio vulgaris. D. vulgaris and C. vibrioforme can catalyze three reactions constituting a complete anaerobic sulfur cycle: reduction of sulfate to sulfide (D. vulgaris), oxidation of sulfide to elemental sulfur (C. vibrioforme), and oxidation of sulfur to sulfate (C. vibrioforme). In all experiments, the first and last reactions favored concentration of the light 32S isotope in products (isotopic fractionation factor epsilon = -7.2 and -1.7%, respectively), whereas oxidation of sulfide favored concentration of the heavy 34S isotope in products (epsilon = +1.7%). Experimental results and model calculations suggest that elemental sulfur enriched in 34S versus sulfide may be a biogeochemical marker for the presence of sulfide-oxidizing bacteria in modern and ancient environments. PMID:11536596

  3. 34S/32S fractionation in sulfur cycles catalyzed by anaerobic bacteria

    NASA Technical Reports Server (NTRS)

    Fry, B.; Gest, H.; Hayes, J. M.

    1988-01-01

    Stable isotopic distributions in the sulfur cycle were studied with pure and mixed cultures of the anaerobic bacteria, Chlorobium vibrioforme and Desulfovibrio vulgaris. D. vulgaris and C. vibrioforme can catalyze three reactions constituting a complete anaerobic sulfur cycle: reduction of sulfate to sulfide (D. vulgaris), oxidation of sulfide to elemental sulfur (C. vibrioforme), and oxidation of sulfur to sulfate (C. vibrioforme). In all experiments, the first and last reactions favored concentration of the light 32S isotope in products (isotopic fractionation factor epsilon = -7.2 and -1.7%, respectively), whereas oxidation of sulfide favored concentration of the heavy 34S isotope in products (epsilon = +1.7%). Experimental results and model calculations suggest that elemental sulfur enriched in 34S versus sulfide may be a biogeochemical marker for the presence of sulfide-oxidizing bacteria in modern and ancient environments.

  4. The (32)S/(33)S abundance as a function of galactocentric radius in the Milky Way

    NASA Technical Reports Server (NTRS)

    Greenhouse, M. A.; Thronson, H. A., Jr.

    1986-01-01

    Astration of heavy elements by the stars of the Milky Way forms a fossil record which may preserve spacial distribution of the mass function for the stars in the galaxy. Sulfur is among the last common element for which the relative abundance of its various isotopes have yet to be completely measured within our galaxy. Explosive oxygen burning in massive stars is thought to be the process which dominates sulfur production within stars. There models predict that the various isotopes (S-32, S-33, S-34) are formed in relative abundance which depend strongly upon the mass of the parent star. This relative abundance is thought to be unaffected by subsequent stellar procesing since all important sinks of sulfur destroy it without regard for isotopic form. Hence the spacial variation of the mass function (MF) can be studied by measuring the abundance variation of sulfur isotopes in the galaxy provided that the product yields for these isotopes are known accurately as a function of stellar mass.

  5. δ34S and Δ33S records of Paleozoic seawater sulfate based on the analysis of carbonate associated sulfate

    NASA Astrophysics Data System (ADS)

    Wu, Nanping; Farquhar, James; Strauss, Harald

    2014-08-01

    This study updates the δ34S and Δ33S temporal records of Paleozoic and early Mesozoic seawater sulfate using analysis of carbonate associated sulfate of biogenic and whole rock carbonate. The time resolution of carbonate samples studied here is on the order of millions of years which is longer than the timescale for homogenization of seawater sulfate-sulfur (one tenth of a million years), but is comparable to the timescale for isotope evolution of sulfate in the oceans. This δ34S record confirms the long-term decreasing trend that is discernible over the 250 million year timescale of sampling, and the Δ33S record of seawater sulfate for the Paleozoic is consistent with an average value of -0.002±0.004‰ (2σ, 540-251 Ma) that is distinct from the positive Δ33S observed today and inferred for the rest of the Cenozoic. Both δ34S and Δ33S records of seawater sulfate suggest the presence of shorter-timescale variations that occur on timescales of tens of millions of years, arguably driven by changes in intensity of sulfide oxidation in cycling of sulfur and/or by rapid changes in sulfur influx to the oceans and its associated sulfur isotopes. The Permian-Triassic boundary marks a transition in co-trajectories of δ34S and Δ33S from in-phase to anti-phase. The biogeochemical forcing that causes this is unclear. This newly calibrated record remains consistent with an earlier assertion (Wu et al., 2010) that the sulfur isotope fractionation (Δ34SSW-PY) between oceanic sulfate (δ34SSW) and coeval sedimentary pyrite (δ34SPY) was smaller during the Paleozoic than in the Cenozoic, and reached lowest values during the Carboniferous. The δ34SIN and Δ33SIN estimates of influx sulfur to the oceans afforded by the isotope mass balance model for each geologic period throughout the Paleozoic reveal a change from higher positive values of δ34SIN (more negative values of Δ33SIN, approximately -0.030‰) to lower positive values of δ34SIN (slightly negative values of

  6. The abundance of 28Si32S, 29Si32S, 28Si34S, and 30Si32S in the inner layers of the envelope of IRC+10216

    PubMed Central

    Fonfría, J. P.; Cernicharo, J.; Richter, M. J.; Fernández-López, M.; Prieto, L. Velilla; Lacy, J. H.

    2016-01-01

    We present high spectral resolution mid-IR observations of SiS towards the C-rich AGB star IRC+10216 carried out with the Texas Echelon-cross-Echelle Spectrograph mounted on the NASA Infrared Telescope Facility. We have identified 204 ro-vibrational lines of 28Si32S, 26 of 29Si32S, 20 of 28Si34S, and 15 of 30Si32S in the frequency range 720 – 790 cm−1. These lines belong to bands v = 1 – 0, 2 – 1, 3 – 2, 4–3, and 5–4, and involve rotational levels with Jlow ≲ 90. About 30 per cent of these lines are unblended or weakly blended and can be partially or entirely fitted with a code developed to model the mid-IR emission of a spherically symmetric circumstellar envelope composed of expanding gas and dust. The observed lines trace the envelope at distances to the star ≲ 35R⋆(≃ 0″.7). The fits are compatible with an expansion velocity of 1+2.5(r/R⋆ −1) km s−1 between 1 and 5R⋆, 11 km s−1 between 5 and 20R⋆, and 14.5 km s−1 outwards. The derived abundance profile of 28Si32S with respect to H2 is 4.9 × 10−6 between the stellar photosphere and 5R⋆, decreasing linearly down to 1.6 × 10−6 at 20R⋆ and to 1.3 × 10−6 at 50R⋆. 28Si32S seems to be rotationally under LTE in the region of the envelope probed with our observations and vibrationally out of LTE in most of it. There is a red-shifted emission excess in the 28Si32S lines of band v = 1 – 0 that cannot be found in the lines of bands v = 2 – 1, 3 – 2, 4 – 3, and 5 – 4. This excess could be explained by an enhancement of the vibrational temperature around 20R⋆ behind the star. The derived isotopic ratios 28Si/29Si, and 32S/34S are 17 and 14, compatible with previous estimates. PMID:26997679

  7. Evaluation of the 34S/32S ratio of Soufre de Lacq elemental sulfur isotopic reference material by continuous flow isotope-ratio mass spectrometry

    USGS Publications Warehouse

    Qi, H.P.; Coplen, T.B.

    2003-01-01

    Soufre de Lacq elemental sulfur reference material (IAEA-S-4) isotopically is homogeneous in amounts as small as 41 ??g as determined by continuous flow isotope-ratio mass spectrometry. The ??34S value for this reference material is +16.90 ?? 0.12??? (1??) on a scale (Vienna Can??on Diablo troilite, VCDT) where IAEA-S-1 Ag2S is -0.3??? and IAEA-S-2 Ag2S is +22.67???. Published by Elsevier Science B.V.

  8. Empirical infrared line lists for five SO2 isotopologues: 32/33/34/36S16O2 and 32S18O2

    NASA Astrophysics Data System (ADS)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

    2015-05-01

    Using the latest published, empirically refined potential energy surface (PES) Ames-1 and purely ab initio CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), we have computed infrared line lists for five symmetric isotopologues of sulfur dioxide: 32S16O2 (626), 33S16O2 (636), 34S16O2 (646), 36S16O2 (666), and 32S18O2 (828). The line lists are based on J = 0-80 rovibrational variational calculations with E‧ ⩽ 8000 cm-1. The 34S16O2 and 33S16O2 line lists are compared to the experiment-based models in the HIgh-resolution TRANsmission molecular absorption database (HITRAN2012,

  9. Rotational Spectroscopy of HB 33S: The Quadrupole Coupling Constant of 33S in Thioborine

    NASA Astrophysics Data System (ADS)

    Bizzocchi, L.; Degli Esposti, C.; Dore, L.

    2002-10-01

    The unstable HBS molecule has been produced in the gas phase by a high-temperature reaction between crystalline boron and hydrogen sulfide. Ground state rotational spectra have been observed in the millimeter-wave region, from 75 to 460 GHz, for the previously unobserved H 11B 33S and H 10B 33S isotopic species. The analysis of the hyperfine structure produced by the 10/11B and 33S nuclear spins in the low- J rotational transitions has yielded the first evaluation of the quadrupole coupling constant of 33S in the thioborine molecule, which was 6.361(15) MHz in H 11B 33S and 6.329(17) MHz in H 10B 33S. In addition, further measurements have been performed for the most abundant isotopomers H 10/11B 32/34S, for which improved values of rotational, centrifugal, and hyperfine structure constants have been determined.

  10. Discrimination between 34S and 32S during bacterial metabolism of inorganic sulfur compounds.

    PubMed Central

    Fry, B; Cox, J; Gest, H; Hayes, J M

    1986-01-01

    Sulfur isotope effects during the oxidation of thiosulfate by Thiobacillus versutus were found to be negligible. This result is considered in relation to other oxidative and reductive processes to assess which reactions are most likely to control the isotopic compositions of sulfur compounds in microbial sulfureta. PMID:3941049

  11. Level-scheme investigation of 33S

    NASA Astrophysics Data System (ADS)

    Gavrilov, G. Tz; Goutev, N.; Dimitrov, B. I.; Tonev, D.; Petkov, P.; de Angelis, G.; Recchia, F.; Farnea, E.; Ur, C. A.; Aydin, S.; Bizzeti, P. G.; Bizzeti-Sona, A. M.; Deloncle, I.; Gottardo, A.; Laftchiev, H.; Lunardi, S.; Mengoni, D.; Michelangoli, C.; Napoli, D. R.; Orlandi, R.; Sahin, E.; Stefanova, E. A.; Valente-Dobon, J. J.; Marinov, Tz K.; Yavahchova, M. S.

    2014-09-01

    An angular correlation experiment was carried out for 33 S at Laboratori Nazionali di Legnaro with the gamma-ray detector array GASP. The reaction used was 24Mg(14N,α p)33S at a beam energy of 40MeV. An analysis of DCO ratios and triple gamma coincidences was performed. So far, a new level depopulated by 3 γ -ray transitions has been found and its spin was determined. The work for further extension of the level scheme is in progress.

  12. Electromagnetic transition strengths in 33S

    NASA Astrophysics Data System (ADS)

    Dimitrov, B. I.; Goutev, N.; Gavrilov, G. Tz; Tonev, D.; Petkov, P.; de Angelis, G.; Recchia, F.; Farnea, E.; Ur, C. A.; Aydin, S.; Bizzeti, P. G.; Bizzeti-Sona, A. M.; Deloncle, I.; Gottardo, A.; Laftchiev, H.; Lunardi, S.; Mengoni, D.; Michelangoli, C.; Napoli, D. R.; Orlandi, R.; Sahin, E.; Stefanova, E. A.; Valente-Dobon, J. J.; Marinov, Tz K.; Yavahchova, M. S.

    2014-09-01

    An experiment using the Doppler Shift Attenuation Method was performed for33S at Laboratori Nazionali di Legnaro using the multi-detector array GASP. Excited states were populated in the fusion-evaporation reaction 24Mg(14N,α p)33S. The data were analyzed using the Differential Decay Curve Method with gates set on the shifted component of a directly feeding transition thus eliminating the problem of the unobserved feeding. Reliable and precise lifetimes were determined and the data derived for the reduced transition probabilities are going to be compared to the predictions of shell model calculations.

  13. Branches of {sup 33}S(p,{gamma}){sup 34}Cl at oxygen-neon nova temperatures

    SciTech Connect

    Freeman, B. M.; Wrede, C.; Delbridge, B. G.; Garcia, A.; Knecht, A.; Sallaska, A. L.; Parikh, A.

    2011-04-15

    Recent simulations of classical novae on oxygen-neon white-dwarf stars indicate that the isotopic ratio {sup 32}S/{sup 33}S has the potential to be a remarkable indicator of presolar grains of nova origin. The {sup 33}S(p,{gamma}){sup 34}Cl reaction influences this ratio directly by destroying {sup 33}S in novae. Additionally, {beta}-delayed {gamma} rays from the metastable state of {sup 34}Cl (t{sub 1/2}=32 min) have been suggested to be potential nova observables. We have measured the branches for known {sup 33}S(p,{gamma}){sup 34}Cl resonances that are activated at temperatures relevant to oxygen-neon novae. We provide the first reliable uncertainties on these branches and the first upper limits for several previously unmeasured branches.

  14. Intermittency in sup 32 S + S and sup 32 S + Au collisions at the CERN SPS

    SciTech Connect

    Bloomer, M.A.; Jacobs, P.

    1991-12-01

    Nonstatistical or intermittent'' fluctuations of charged particle multiplicities have been investigated at the CERN SPS with the WA80 multiplicity array for {sup 32}S+S and {sup 32}S+Au collisions of varying centrality. Within the phase space domain studied there is no evidence for intermittency in these collisions beyond that accounted for by FRITIOF filtered through a full detector simulation.

  15. Intermittency in {sup 32}S + S and {sup 32}S + Au collisions at the CERN SPS

    SciTech Connect

    Bloomer, M.A.; Jacobs, P.; WA80 Collaboration

    1991-12-01

    Nonstatistical or ``intermittent`` fluctuations of charged particle multiplicities have been investigated at the CERN SPS with the WA80 multiplicity array for {sup 32}S+S and {sup 32}S+Au collisions of varying centrality. Within the phase space domain studied there is no evidence for intermittency in these collisions beyond that accounted for by FRITIOF filtered through a full detector simulation.

  16. Determination of the δ34S of Total Sulfur in Solids: RSIL Lab Code 1800

    USGS Publications Warehouse

    Revesz, Kinga; Coplen, Tyler B.

    2006-01-01

    The purpose of Reston Stable Isotope Laboratory Lab (RSIL) Code 1800 is to determine the δ(34S/32S), abbreviated as δ34S, of total sulfur in a solid sample. A Carlo Erba NC 2500 elemental analyzer (EA) is used to convert total sulfur in a solid sample into SO2 gas. The EA is connected to a continuous flow isotope-ratio mass spectrometer (CF-IRMS), which determines the relative difference in stable sulfur isotope-amount ratio (34S/32S) of the product SO2 gas. The combustion is quantitative; no isotopic fractionation is involved. Samples are placed in tin capsules and loaded into a Costech Zero-Blank Autosampler on the EA. Under computer control, samples are dropped into a heated tube reaction tube that combines both the oxidation and the reduction reactions. The combustion takes place in a He atmosphere that contains an excess of oxygen gas at the oxidation zone at the top of the reaction tube. Combustion products are transported by a He carrier through the reduction zone at the bottom of the reaction tube to remove excess oxygen and through a separate drying tube to remove any water. The gas-phase products, mainly CO2, N2, and SO2, are separated by a gas chromatograph (GC). The gas is then introduced into the isotope-ratio mass spectrometer (IRMS) through a Thermo-Finnigan ConFlo II interface, which also is used to inject SO2 reference gas and He for sample dilution. The IRMS is a Thermo-Finnigan DeltaPlus CF-IRMS. It has a universal triple collector with two wide cups and a narrow cup in the middle. It is capable of measuring mass/charge (m/z) 64 and 66 simultaneously. The ion beams from SO2 are as follows: m/z 64 = SO2 = 32S16O16O; and m/z 66 = SO2 = 34S16O16O primarily.

  17. Determination of the δ34S of sulfate in water; RSIL lab code 1951

    USGS Publications Warehouse

    Revesz, Kinga; Qi, Haiping; Coplen, Tyler B.

    2006-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1951 is to determine the δ(34S/32S), abbreviated as δ34S, of dissolved sulfate. Dissolved sulfate is collected in the field and precipitated with BaCl2 at pH 3 to 4 as BaSO4 in the laboratory. However, the dissolved organic sulfur (DOS) is oxidized to SO2, and the carbonate is acidified to CO2. Both are degassed from the water sample before the sulfate is precipitated. The precipitated BaSO4 is filtered and dried before introduction into an elemental analyzer (EA) Carlo Erba NC 2500. The EA is used to convert sulfur in a BaSO4 solid sample into SO2 gas, and the EA is connected to a continuous flow isotope-ratio mass spectrometer (CF-IRMS), which determines the differences in the isotope-amount ratios of stable sulfur isotopes (34S/32S) of the product SO2 gas. The combustion is quantitative; no isotopic fractionation is involved. Samples are placed in a tin capsule and loaded into the Costech Zero Blank Autosampler of the EA. Under computer control, samples are dropped into a heated tube reaction tube that combines the oxidation and reduction reactions. The combustion takes place in a helium atmosphere containing an excess of oxygen gas at the oxidation zone at the top of the reaction tube. Combustion products are transported by a helium carrier through the reduction zone at the bottom of the reaction tube to remove excess oxygen and through a separate drying tube to remove any water. The gas-phase products, mainly CO2, N2, and SO2, are separated by a gas chromatograph. The gas is then introduced into the isotope-ratio mass spectrometer (IRMS) through a Finnigan MAT (now Thermo Scientific) ConFlo II interface, which also is used to inject SO2 reference gas and helium for sample dilution. The IRMS is a Thermo Scientific Delta V Plus CF-IRMS. It has a universal triple collector with two wide cups and a narrow cup in the middle. It is capable of measuring mass/charge (m/z) 64 and 66 simultaneously

  18. 33S NMR spectroscopy 3. Substituent effects on 33S NMR parameters in 2-substituted ethanesulfonates.

    PubMed

    Musio, Roberta; Sciacovelli, Oronzo

    2006-08-01

    33S NMR parameters (chemical shifts and linewidths) in 2-substituted sodium ethanesulfonates, XCH2CH2SO3Na (X = H, CH3, OH, SH, NH2, Cl, Br, NH3+) depend upon the electronic properties of substituents. To explain experimental results and obtain additional information on the origin of the observed substituent effect (SE), sulfur isotropic absolute shielding constants have been calculated at DFT level of theory (B3LYP/6-311++G(2d,p)) by gauge-including atomic orbitals (GIAO) method. Data have been interpreted with the aid of natural bond orbital (NBO) method and natural chemical shielding (NCS) analysis. It has been demonstrated that in the class of compounds considered the diamagnetic contribution to sulfur-shielding constant is constant and the observed upfield shift of 33S resonance induced by electron-withdrawing substituents (reverse chemical shift effect) can be related to variations of the paramagnetic contribution. Substituents with different electronic properties cause variations in the polarization of S-C and S-O bonds of the -C-SO3- moiety thus determining changes of the electron density at sulfur nucleus and consequently the expansion or contraction of 3p sulfur orbitals. Also oxygen lone-pairs and sulfur core 2p electrons can play an active role in determining the paramagnetic contribution to sulfur shielding. With regard to linewidth variations, they can be ascribed primarily to changes in the nuclear quadrupole coupling constant values. B3LYP/6-311++G(2d,p) method allows obtaining a good reproducibility of SE on the electric field gradient (EFG) at sulfur, although its values tend to be underestimated significantly. Moreover, 17O shielding constants have been calculated. PMID:16741982

  19. Oxygen isotope corrections for online δ34S analysis

    USGS Publications Warehouse

    Fry, B.; Silva, S.R.; Kendall, C.; Anderson, R.K.

    2002-01-01

    Elemental analyzers have been successfully coupled to stable-isotope-ratio mass spectrometers for online measurements of the δ34S isotopic composition of plants, animals and soils. We found that the online technology for automated δ34S isotopic determinations did not yield reproducible oxygen isotopic compositions in the SO2 produced, and as a result calculated δ34S values were often 1–3‰ too high versus their correct values, particularly for plant and animal samples with high C/S ratio. Here we provide empirical and analytical methods for correcting the S isotope values for oxygen isotope variations, and further detail a new SO2-SiO2 buffering method that minimizes detrimental oxygen isotope variations in SO2.

  20. Determination of the δ34S of low-concentration sulfate in water; RSIL lab code 1949

    USGS Publications Warehouse

    Revesz, Kinga; Qi, Haiping; Coplen, Tyler B.

    2006-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 1949 is to determine the δ(34S/32S), abbreviated as δ34S, of dissolved sulfate having a concentration less than 20 milligrams per liter. Dissolved sulfate is collected on an anion-exchange resin in the field, eluted in the laboratory with 3 M KCl, and precipitated with BaCl2 at pH 3 to 4 as BaSO4. The precipitated BaSO4 is filtered and dried before introduction into an elemental analyzer (EA) Carlo Erba NC 2500. The EA is used to convert sulfur in a BaSO4 solid sample into SO2 gas, and the EA is connected to a continuous flow isotope-ratio mass spectrometer (CF-IRMS), which determines differences in the isotope-amount ratios of stable sulfur isotopes (34S/32S) of the product SO2 gas. The combustion is quantitative; no isotopic fractionation is involved. Samples are placed in a tin capsule and loaded into the Costech Zero Blank Autosampler of the EA. Under computer control, samples are dropped into a heated reaction tube that combines the oxidation and reduction reactions. The combustion takes place in a helium atmosphere containing an excess of oxygen gas at the oxidation zone at the top of the reaction tube. Combustion products are transported by a helium carrier through the reduction zone at the bottom of the reaction tube to remove excess oxygen and through a separate drying tube to remove any water. The gas-phase products, mainly CO2, N2, and SO2, are separated by a gas chromatograph. The gas is then introduced into the isotope-ratio mass spectrometer (IRMS) through a Finnigan MAT (now Thermo Scientific) ConFlo II interface, which is also used to inject SO2 reference gas and helium for sample dilution. The IRMS is a Thermo Scientific Delta V Plus CF-IRMS. It has a universal triple collector with two wide cups and a narrow cup in the middle. It is capable of measuring mass/charge (m/z) 64 and 66 simultaneously. The ion beams from SO2 are as follows: m/z 64 = SO2 = 32S16O16O; m/z 66 = SO2 = 34S

  1. The chemical conditions of the late Archean Hamersley basin inferred from whole rock and pyrite geochemistry with Δ33S and δ34S isotope analyses

    NASA Astrophysics Data System (ADS)

    Gregory, Daniel D.; Large, Ross R.; Halpin, Jacqueline A.; Steadman, Jeffery A.; Hickman, Arthur H.; Ireland, Trevor R.; Holden, Peter

    2015-01-01

    The well-preserved late Archean sedimentary rocks of the Fortescue and Hamersley Basins in Western Australia offer fascinating insights into early earth ocean chemistry prior to the Great Oxidation Event (GOE). In this study, we use a combination of whole rock geochemistry, LA-ICPMS trace element analysis of sedimentary pyrite and pyrrhotite and SHRIMP-SI sulfur isotope analyses to elucidate the chemical changes in these sedimentary rocks. These proxies are used to examine chemical conditions of the ocean during the late Archean. Two to three periods of oxygen enrichment prior to the deposition of banded iron formations (BIF) can be identified. One minor stage of general increase in whole rock enrichment factors and trace element content of pyrite is observed up stratigraphy in the Jeerinah Formation, Fortescue Basin and a more substantial stage is present in the Paraburdoo and Bee Gorge Members of the Wittenoom Formation, Hamersley Basin. Some of the trace element enrichments indicate organic matter burial flux (Ni, Cr, Zn, Co and Cu) which suggests an increase in biological productivity. If the increased biological activity reflects an increase in cyanobacteria activity then an associated increase in oxygen is likely to have occurred during the deposition of the Bee Gorge Member. An increase in atmospheric oxygen would result in continental weathering of sulfide and other minerals, increasing the trace element content of the water column via erosion and avoiding excessive depletion of trace elements due to drawdown in seawater. Since some of these trace elements may also be limiting nutrients (such as Mo and Se) for the cyanobacteria, the degree of biological productivity may have further increased due to the increasing amount of trace elements introduced by oxygenation in a positive feedback loop. These periods of increased productivity and oxygen rise stopped prior to the onset of BIF deposition in the Hamersley Basin. This may be due to the ocean reaching an oxidation threshold, enabling the precipitation of hematite and magnetite BIF. The BIF deposition caused depletion of ocean nutrients such as phosphate, severely limiting the growth of cyanobacteria, and thus limiting further oxygen production.

  2. 34S/32S and 18O/16O ratios of dissolved sulfate from interstitial water samples above gas hydrate bearing sediments of IODP Expedition 311, Cascadia

    NASA Astrophysics Data System (ADS)

    Wortmann, U. G.; Chernyavsky, B. M.; Torres, M. E.; Kastner, M.

    2008-12-01

    Microbially mediated sulfate reduction affects the isotopic composition of dissolved and solid sulfur species in marine sediments. Although several details of the fractionation process remain controversial, the overall process is well understood and can be described as the sum of several mass dependent fractionations during the stepwise reduction of sulfate to sulfide. Experiments and field data show that the 18O/16O of sulfate is also modified in the presence of sulfate-reducing microorganisms. Here we use a reaction transport model to analyze these processes and to constrain the rates of organotrophic versus methanotrophic sulfate reduction. Our results show that even in cases where sulfate concentrations decline in a linear fashion, up to 50% of all sulfate is consumed by organotrophic sulfate reduction.

  3. Improving the {sup 33}S(p,{gamma}){sup 34}Cl Reaction Rate for Models of Classical Nova Explosions

    SciTech Connect

    Parikh, A.; Faestermann, Th.; Kruecken, R.; Bildstein, V.; Bishop, S.; Eppinger, K.; Herlitzius, C.; Lepyoshkina, O.; Maierbeck, P.; Seiler, D.; Wimmer, K.; Hertenberger, R.; Wirth, H.-F.; Fallis, J.; Hager, U.; Hutcheon, D.; Ruiz, Ch.; Buchmann, L.; Ottewell, D.; Freeman, B.

    2011-10-28

    Reduced uncertainty in the thermonuclear rate of the {sup 33}S(p,{gamma}){sup 34}Cl reaction would help to improve our understanding of nucleosynthesis in classical nova explosions. At present, models are generally in concordance with observations that nuclei up to roughly the calcium region may be produced in these explosive phenomena; better knowledge of this rate would help with the quantitative interpretation of nova observations over the S-Ca mass region, and contribute towards the firm establishment of a nucleosynthetic endpoint. As well, models find that the ejecta of nova explosions on massive oxygen-neon white dwarfs may contain as much as 150 times the solar abundance of {sup 33}S. This characteristic isotopic signature of a nova explosion could possibly be observed through the analysis of microscopic grains formed in the environment surrounding a nova and later embedded within primitive meteorites. An improved {sup 33}S(p,{gamma}){sup 34}Cl rate (the principal destruction mechanism for {sup 33}S in novae) would help to ensure a robust model prediction for the amount of {sup 33}S that may be produced. Finally, constraining this rate could confirm or rule out the decay of an isomeric state of {sup 34}Cl(E{sub x} = 146 keV, t{sub 1/2} = 32 m) as a source for observable gamma-rays from novae. We have performed several complementary experiments dedicated to improving our knowledge of the {sup 33}S(p,{gamma}){sup 34}Cl rate, using both indirect methods (measurement of the {sup 34}S({sup 3}He,t){sup 34}Cl and {sup 33}S({sup 3}He,d){sup 34}Cl reactions with the Munich Q3D spectrograph) and direct methods (in normal kinematics at CENPA, University of Washington, and in inverse kinematics with the DRAGON recoil mass separator at TRIUMF). Our results will be used with nova models to facilitate comparisons of model predictions with present and future nova observables.

  4. Elastic scattering and quasielastic transfer for {sup 32}S+{sup 96,100}Mo at {ital E}{sub lab}=180 MeV

    SciTech Connect

    Herrick, D.M.; Wolfs, F.L.H.; Bryan, D.C.; Freeman, C.G.; Kurz, K.L.; Mathews, D.H.; Perera, P.A.A.; Zanni, M.T.

    1995-08-01

    Cross sections for elastic scattering and quasielastic transfer have been measured for {sup 32}S+{sup 96,100}Mo at {ital E}{sub lab}=180 MeV ({similar_to}60% above the Coulomb barrier). The transfer yields are dominated by the ({sup 32}S, {sup 33}S) and ({sup 32}S, {sup 31}P) reactions which account for about 50% of the total quasielastic transfer strength. The transfer probabilities show an exponential decrease with increasing distance of closest approach. The measured decay constants are smaller than the binding-energy derived decay constants. The observed enhancements of the transfer probabilities for the simplest single-step transfer reactions (involving the transfer of up to two nucleons) can be understood quantitatively in terms of quantum diffraction.

  5. Resonance strengths of the 34S + α reaction

    NASA Astrophysics Data System (ADS)

    O'Malley, P. D.; Connolly, Devin; Greife, Uwe; Hager, Ulrike; Ilyushkin, Sergey; Buchmann, Lothar; Christian, Greg; D'Auria, John; Davids, Barry; Fallis, Jennifer; Hutcheon, Dave; Martin, Lars; Ruiz, Chris; Chen, Alan; Setoodehnia, Kiana; Akers, Charles; Fulton, Brian; Laird, Alison; Erikson, Luke

    2014-09-01

    Late in their evolution, particularly massive stars undergo a stage of explosive oxygen burning. The free α-particle density will rapidly increase and initiate a network of reactions among nuclides ranging from 28Si to 40Ca. Next there will be a abrupt rise in the abundances of 34S and 38Ar where the small excess of neutrons reside. The final abundances of nuclei in this mass region depend on the reaction cross sections involving these two nuclei. Currently there are large discrepancies in the strengths of the 34S + α resonances in the energy range of interest for this astrophysical environment. A new measurement was performed at DRAGON to resolve these discrepancies. Preliminary data will be shown and tentative results discussed.

  6. High Resolution Infrared Studies of the v2, v4 Bands of 34S16O3, Including Both Intensity and Wavenumber Perturbations

    SciTech Connect

    Barber, Jeffrey B.; Masiello, Tony; Chrysostom, Engelene; Nibler, Joseph W.; Maki, Arthur; Weber, Alfons; Blake, Thomas A.; Sams, Robert L.

    2003-06-15

    The infrared spectrum of the v2, v4 bending mode region of 34S-substituted sulfur trioxide, 34S16O3, has been recorded at a resolution of 0.0025 cm-1. The v2 and v4 levels are coupled by a Coriolis interaction, yielding significant spectral shifts that have been successfully analyzed to obtain rovibrational constants for the ground state and both fundamentals. Comparisons are made with 32S16O3 parameters and the Bo rotational constant is found to be 0.348 556 04(28) cm-1, only very slightly larger than the corresponding value of 0.348 543 33(5) cm-1 for 32S16O3. Coriolis and l-type resonance interactions between the v2 and v4 levels produce frequency shifts and strong intensity perturbations in the spectra that are considered for both 34S16O3 and 32S16O3. The resulting analysis yields an average value of+0.62(8) for the dipole derivative ratio (?x/?Q4x) (?z/?Q2) and a positive sign for the product of this ratio with the?y2,4 Coriolis constant, for which experiment gives+0.5940(15) . Ab initio calculations indicate that the signs of?x/?Q4x and?z/?Q2 are both positive and hence?y2,4 is also positive, in agreement with earlier calculations. These signs indicate that the effective charge movement in the xz plane has the same sense of rotation as Q2, Q4x atom motion in this plane that produces a py vibrational angular momentum component, correlated motion that is confirmed by ab initio calculations.

  7. Highly Accurate Potential Energy Surface, Dipole Moment Surface, Rovibrational Energy Levels, and Infrared Line List for (32)S(16)O2 up to 8000 cm(exp -1)

    NASA Technical Reports Server (NTRS)

    Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

    2014-01-01

    A purely ab initio potential energy surface (PES) was refined with selected (32)S(16)O2 HITRAN data. Compared to HITRAN, the root-mean-squares error (RMS) error for all J=0-80 rovibrational energy levels computed on the refined PES (denoted Ames-1) is 0.013 cm(exp -1). Combined with a CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), an infrared (IR) line list (denoted Ames-296K) has been computed at 296K and covers up to 8,000 cm(exp -1). Compared to the HITRAN and CDMS databases, the intensity agreement for most vibrational bands is better than 85-90%. Our predictions for (34)S(16)O2 band origins, higher energy (32)S(16)O2 band origins and missing (32)S(16)O2 IR bands have been verified by most recent experiments and available HITRAN data. We conclude that the Ames-1 PES is able to predict (32/34)S(16)O2 band origins below 5500 cm(exp -1) with 0.01-0.03 cm(exp -1) uncertainties, and the Ames-296K line list provides continuous, reliable and accurate IR simulations. The Ka-dependence of both line position and line intensity errors is discussed. The line list will greatly facilitate SO2 IR spectral experimental analysis, as well as elimination of SO2 lines in high-resolution astronomical observations.

  8. Alpha-cluster excited states in 32S

    NASA Astrophysics Data System (ADS)

    Yoshida, Yuta; Y. Kanada-En'yo Collaboration; F. Kobayashi Collaboration

    2014-09-01

    Excited states having core +alpha cluster structure called the alpha-cluster excited state are known to exist in such nuclei as 16O and 20Ne. Meanwhile, the existence of alpha-cluster excited states in the middle of sd-shell nuclei is an open problem. Recently, the alpha-cluster excited state in 32S is suggested by experiments. In order to understand the dynamics of the core-alpha relative motion, we focus on the structure change of the core nuclei and the breaking of the alpha-cluster. In the present work, we construct 28Si +alpha model which has the structure change of the 28Si core and the alpha-cluster breaking. Using the present model, we calculate the energy expectation value of 28Si +alpha system. We found that the structure change of the core nuclei is energetically rather important while the alpha-cluster breaking is not significant when the alpha-cluster exists at the surface of the 28Si core. We calculate the ground and excited states with the generator coordinate method. As a result, we suggest the existence of alpha-cluster excited states in 32S.

  9. α-cluster excited states in 32S

    NASA Astrophysics Data System (ADS)

    Yoshida, Yuta; Kanada-En'yo, Yoshiko; Kobayashi, Fumiharu

    2016-04-01

    α -cluster excited states in ^{32}S are investigated with an extended ^{28}Si+α cluster model, in which the ^{28}Si core deformation and rotation and the α -cluster breaking are incorporated. In the generator coordinate method calculation with the extended ^{28}Si+α cluster model, the α -cluster excited states are obtained near the ^{28}Si+α threshold energy. The ^{28}Si core deformation and rotation effects, and also the α -clusters breaking in the ^{28}Si+α system, are discussed. It is found that the rotation of the oblately deformed ^{28}Si core has a significant effect on the α -cluster excited states whereas the α -cluster breaking has only a minor effect.

  10. A mantle origin for Paleoarchean peridotitic diamonds from the Panda kimberlite, Slave Craton: Evidence from 13C-, 15N- and 33,34S-stable isotope systematics

    NASA Astrophysics Data System (ADS)

    Cartigny, Pierre; Farquhar, James; Thomassot, Emilie; Harris, Jeffrey W.; Wing, Bozwell; Masterson, Andy; McKeegan, Kevin; Stachel, Thomas

    2009-11-01

    In order to address diamond formation and origin in the lithospheric mantle underlying the Central Slave Craton, we report N- and C-stable isotopic compositions and N-contents and aggregation states for 85 diamonds of known paragenesis (73 peridotitic, 8 eclogitic and 4 from lower mantle) from the Panda kimberlite (Ekati Mine, Lac de Gras Area, Canada). For 12 peridotitic and two eclogitic sulfide inclusion-bearing diamonds from this sample set, we also report multiple-sulfur isotope ratios. The 73 peridotitic diamonds have a mean δ13C-value of - 5.2‰ and range from - 6.9 to - 3.0‰, with one extreme value at - 14.1‰. The associated δ15N-values range from - 17.0 to + 8.5‰ with a mean value of - 4.0‰. N-contents range from 0 to 1280 ppm. The 8 eclogitic diamonds have δ13C-values ranging from - 11.2 to - 4.4‰ with one extreme value at - 19.4‰. Their δ15N ranges from - 2.1 to + 7.9‰ and N-contents fall between 0 and 3452 ppm. Four diamonds with an inferred lower mantle origin are all Type II (i.e. nitrogen-free) and have a narrow range of δ13C values, between - 4.5 and - 3.5‰. The δ34S of the 14 analyzed peridotitic and eclogitic sulfide inclusions ranges from - 3.5 to +5.7‰. None of them provide evidence for anomalous δ33S-values; observed variations in δ33S are from +0.19 to - 0.33‰, i.e. within the 2 sigma uncertainties of mantle sulfur ( δ33S = 0‰). At Panda, the N contents and the δ13C of sulfide-bearing peridotitic diamonds show narrower ranges than silicate-bearing peridotitic diamonds. This evidence supports the earlier suggestion established from eclogitic diamonds from the Kaapvaal that sulfide-(±silicate) bearing diamonds sample a more restricted portion of sublithospheric mantle than silicate-(no sulfide) bearing diamonds. Our findings at Panda suggest that sulfide-bearing diamonds should be considered as a specific diamond population on a global-scale. Based on our study of δ34S, Δ 33S, δ15N and δ13C, we find no

  11. Simultaneous N, C, S isotopic analyses using purge and trap EA technology. Application to δ34S analyses of natural phosphate material NBS120c and BCR32

    NASA Astrophysics Data System (ADS)

    Fourel, F. P.; Lecuyer, C.; Martineau, F.

    2013-12-01

    The first example of stable isotope analyses in continuous flow mode by Preston et al in 19861 involved Elemental Analyser Isotopic Ratio Mass Spectrometry (EA-IRMS) dedicated to carbon isotopes in combustion mode. EA-IRMS has since then evolved to allow 34S/32S determinations still in combustion mode and mainly to access pyrolysis reaction for O and H isotopes. As far as combustion EA-IRMS is concerned the technique itself has remained unchanged since the development of 'purge and trap' separation techniques online with IRMS instruments. Here we have used a high-precision, easy, low-cost and rapid method of simultaneous carbon, nitrogen and sulphur isotope analysis using this new type of elemental analyser based on 'purge and trap' technology 2,3. Simultaneous determinations, performed on the same aliquot of 13C, 15N and 34S are demonstrated. Emphasis is put on the high quality of 34S/32S determinations. First concentrating on peak shapes, yields of conversion and preliminary results. Then the reliability and accuracy of such a technique is illustrated using analyses from various international reference materials. Alongside international reference material working NCS calibrated material has been selected and characterized prior to apply this technology to calibrate natural phosphate material used as compositional reference material BCR32 and NBS120c. δ34S values of respectively 15.62×0.32‰ and 16.5×0.17‰ are proposed for those samples with sulphur concentrations below the 1% level. The possibility to reliably measure S isotopes on that kind of samples opens up new fields of investigation especially for paleoenvironmental reconstructions. Keywords: carbon, nitrogen, sulfur, isotope, combustion, phosphate, elemental-analyser 1. T. Preston, N.J.P. Owens: Preliminary 13C Measurements using a Gas Chromatograph Interfaced to an Isotope Ratio Mass Spectrometer. Biomedical. Mass Spectrom. 1985, 12-9, 510. 2. H.P. Sieper, H.J. Kupka, L. Lange, A. Rossmann, N. Tanz

  12. Detection of Taurine in Biological Tissues by 33S NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Musio, Roberta; Sciacovelli, Oronzo

    2001-12-01

    The potential of 33S NMR spectroscopy for biochemical investigations on taurine (2-aminoethanesulfonic acid) is explored. It is demonstrated that 33S NMR spectroscopy allows the selective and unequivocal identification of taurine in biological samples. 33S NMR spectra of homogenated and intact tissues are reported for the first time, together with the spectrum of a living mollusc. Emphasis is placed on the importance of choosing appropriate signal processing methods to improve the quality of the 33S NMR spectra of biological tissues.

  13. Isotopic Equilibration Between Sulfide and Organic Matter: Implications for Records of Sedimentary δ34S.

    NASA Astrophysics Data System (ADS)

    Raven, M. R.; Sessions, A. L.; Adkins, J. F.; Fischer, W. W.

    2015-12-01

    Records of the sulfur-isotopic composition of sedimentary pyrite have been used to constrain the evolutionary timing of major metabolic pathways, the size of the marine sulfate reservoir, and the redox balance of the planet. It remains a major challenge, however, to explain the enormous range of pyrite δ34S values in the literature and their typical ~10‰ offset relative to sedimentary organic S. We investigate the development of pyrite and organic S records in Santa Barbara Basin, which has suboxic bottom water and high (≥4 wt%) organic matter burial. Concentration and δ34S profiles of major sulfur species (sulfate, sulfide, elemental S, proto-kerogen, pyrite, and extractable organic matter) suggest the occurrence of S-isotope exchange between porewater sulfide and organic S, so we conducted laboratory experiments to test organic S exchangeability with 34S-labelled sulfide-polysulfide solutions. We found that both extractable and proto-kerogen organic matter incorporated significant amounts of label within days, supporting the feasibility of equilibration between sulfide and organic matter in the environment. Unlike organic S, pyrite δ34S values in Santa Barbara Basin sediments are up to 30‰ lower than those for porewater sulfide. We hypothesize that this strongly 34S-depleted pyrite reflects the immediate products of bacterial sulfate reduction at organic-rich structures like microbial biofilms or aggregates and suggest that this δ34S difference between porewater sulfide and pyrite may be a more common than previously recognized. Pyrite δ34S values are not necessarily reflective of porewater sulfide δ34S, suggesting that this common assumption should be revisited. Sedimentary pyrite and organic S are potentially powerful and complementary archives of environmental information. To meaningfully interpret these records, it is essential that we take into account the complex processes affecting sedimentary pyrite and organic sulfur δ34S in modern sediments.

  14. Sources and meteorological factors that control seasonal variation of δ34S values in rainwater

    NASA Astrophysics Data System (ADS)

    Xiao, Hong-Wei; Xiao, Hua-Yun; Long, Ai-Min; Wang, Yan-Li; Liu, Cong-Qiang

    2014-11-01

    Sulfate concentrations and sulfur isotopic compositions were measured in rainwater in Guiyang city in Southwest China between October 2008 and September 2009 to identify sulfur sources and their impacts on sulfur isotopic composition. The δ34S values of 1235 samples collected during this period ranged from - 12.0 to + 9.4‰, with a volume-weighted mean of - 2.8 ± 9.8‰, suggesting that rainwater sulfate in Guiyang was mainly derived from SO2 produced during coal combustion. The δ34S values of rainwater sulfate increased from 1987 to 2009, with an increment of about + 0.16‰ per year, reflecting a gradual reduction in 34S-depleted SO2 emitted during coal combustion. Seasonal variations in δ34S values were pronounced, with higher values in winter than in summer. Long-distance transport of SO2 from coal burned in northern cities (which was higher than the component from southern cities), and more importantly, the aqueous oxidation of SO2 during transport affected the seasonal variation of rainwater δ34S values in Guiyang. Temperature-dependent aqueous oxidation of SO2 suggested that lower rainwater δ34S coincides with higher temperature.

  15. Complete and incomplete fusion in the {sup 32}S+{sup 12}C reaction at E({sup 32}S)=20 MeV/A

    SciTech Connect

    Aiello, S.; Pirrone, S.; Politi, G.; Arena, N.; Cavallaro, Seb.; Sambataro, S.; Geraci, E.; Porto, F.; Lanzalone, G.

    1999-11-16

    Velocity distribution of mass identified evaporation residues produced in the {sup 32}S+{sup 12}C reaction at E({sup 32}S)=20 MeV/A have been measured using time-of-flight techniques. These distributions were used to separate the complete and incomplete fusion components. The complete fusion cross section and the deduced critical angular momenta are compared with other experimental data and the predictions of existing models.

  16. Complete and Incomplete fusion in the {sup 32}S+{sup 12}C reaction at E({sup 32}S)=20 MeV/A

    SciTech Connect

    S. Aiello; N. Arena; S. Cavallaro; E. Geraci; G. Lanzalone; S. Pirrone; G. Politi; F. Porto; S. Sambataro

    1999-12-31

    Velocity distribution of mass identified evaporation residues produced in the {sup 32}S+{sup 12}C reaction at E({sup 32}S)=20 MeV/A have been measured using time-of-flight techniques. These distributions were used to separate the complete and incomplete fusion components. The complete fusion cross section and the deduced critical angular momenta are compared with other experimental data and the predictions of existing models.

  17. In situ sulfur isotopes (δ(34)S and δ(33)S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS.

    PubMed

    Fu, Jiali; Hu, Zhaochu; Zhang, Wen; Yang, Lu; Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong

    2016-03-10

    The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N2 on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4-8 ml min(-1) nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N2 = 4 ml min(-1)). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d90 values of the particles in pressed powder pellets for accurate and precise S isotope analysis should be less than 10 μm. Under the selected optimized analytical conditions, excellent agreements between the determined values and the reference values were achieved for the IAEA-S series standard reference materials and a set of six well-characterized, isotopic homogeneous sulfide standards (PPP-1, MoS2, MASS-1, P-GBW07267, P-GBW07268, P-GBW07270), validating the capability of the developed method for providing high-quality in situ S isotope data in sulfides and elemental sulfur. PMID:26893082

  18. SIMS measurements of. delta. sup 34 S in sulfide minerals from adjacent vein and stratabound ores

    SciTech Connect

    MacFarlane, A.W., ); Shimizu, Nobumichi, )

    1991-02-01

    The effects of sample matrix and secondary ion energy on the instrument fractionation of sulfur isotopes have been studied for troilite, pyrite, and galena using the Caneca IMS-3f ion microprobe. An analytical procedure is described for the measurement of {delta}{sup 34}S on negatively charged sulfur ions from pyrite and galena with are producibility better than {plus minus} 1.5 {per thousand}. Sulfur isotope ratios were measured in pyrite and galena from adjacent stratabound manto orebodies and crosscutting veins in the Hualgayoc district of northern Peru. Isotopic compositions ({delta}{sup 34}S{sub CDT}) of sulfur in pyrite and galena from vein and manto deposits have a total range from {minus}20 to 10 per thousand. Sulfur in manto galenas has a wide range of isotopic compositions and is usually isotopic heavier than pyrite and galena suggests precipitation from separate fluids, consistent with textural evidence that galena is pargentically later than pyrite and often replaces it. The majority of pyrite and galena analyses from vein and manto ores are compatible with precipitation from ore fluids having {delta}{sup 34}S of aqueous sulfur of 0{plus minus} 5 per thousand. This result indicates that the associated igneous rocks may have been the source of sulfur in the ore minerals (as well as of lead). Low values of {delta}{sup 34}S in manto galena may be accounted for by incorporation of sulfur derived from diagenetic iron sulfides.

  19. MC ICP-MS δ(34)S(VCDT) measurement of dissolved sulfate in environmental aqueous samples after matrix separation by means of an anion exchange membrane.

    PubMed

    Hanousek, Ondrej; Berger, Torsten W; Prohaska, Thomas

    2016-01-01

    Analysis of (34)S/(32)S of sulfate in rainwater and soil solutions can be seen as a powerful tool for the study of the sulfur cycle. Therefore, it is considered as a useful means, e.g., for amelioration and calibration of ecological or biogeochemical models. Due to several analytical limitations, mainly caused by low sulfate concentration in rainwater, complex matrix of soil solutions, limited sample volume, and high number of samples in ecosystem studies, a straightforward analytical protocol is required to provide accurate S isotopic data on a large set of diverse samples. Therefore, sulfate separation by anion exchange membrane was combined with precise isotopic measurement by multicollector inductively coupled plasma mass spectrometry (MC ICP-MS). The separation method proved to be able to remove quantitatively sulfate from matrix cations (Ca, K, Na, or Li) which is a precondition in order to avoid a matrix-induced analytical bias in the mass spectrometer. Moreover, sulfate exchange on the resin is capable of preconcentrating sulfate from low concentrated solutions (to factor 3 in our protocol). No significant sulfur isotope fractionation was observed during separation and preconcentration. MC ICP-MS operated at edge mass resolution has enabled the direct (34)S/(32)S analysis of sulfate eluted from the membrane, with an expanded uncertainty U (k = 2) down to 0.3 ‰ (a single measurement). The protocol was optimized and validated using different sulfate solutions and different matrix compositions. The optimized method was applied in a study on solute samples retrieved in a beech (Fagus sylvatica) forest in the Vienna Woods. Both rainwater (precipitation and tree throughfall) and soil solution δ (34)SVCDT ranged between 4 and 6 ‰, the ratio in soil solution being slightly lower. The lower ratio indicates that a considerable portion of the atmospherically deposited sulfate is cycled through the organic S pool before being released to the soil solution

  20. 33S for Neutron Capture Therapy: Nuclear Data for Monte Carlo Calculations

    NASA Astrophysics Data System (ADS)

    Porras, I.; Sabaté-Gilarte, M.; Praena, J.; Quesada, J. M.; Esquinas, P. L.

    2014-06-01

    A study of the nuclear data required for the Monte Carlo simulation of boron neutron capture therapy including the 33S isotope as an enhancer of the dose at small depths has been performed. In particular, the controversy on the available data for the 33S(n, α) cross section will be shown, which motivates new measurements. In addition to this, kerma factors for the main components of tissue are calculated with the use of fitting functions. Finally, we have applied these data to a potential neutron capture treatment with boron and sulfur addition to tissue in which part of the hydrogen atoms are replaced by deuterium, which improves the procedure.

  1. A large column analog experiment of stable isotope variations during reactive transport: I. A comprehensive model of sulfur cycling and δ34S fractionation

    NASA Astrophysics Data System (ADS)

    Druhan, Jennifer L.; Steefel, Carl I.; Conrad, Mark E.; DePaolo, Donald J.

    2014-01-01

    This study demonstrates a mechanistic incorporation of the stable isotopes of sulfur within the CrunchFlow reactive transport code to model the range of microbially-mediated redox processes affecting kinetic isotope fractionation. Previous numerical models of microbially mediated sulfate reduction using Monod-type rate expressions have lacked rigorous coupling of individual sulfur isotopologue rates, with the result that they cannot accurately simulate sulfur isotope fractionation over a wide range of substrate concentrations using a constant fractionation factor. Here, we derive a modified version of the dual-Monod or Michaelis-Menten formulation (Maggi and Riley, 2009, 2010) that successfully captures the behavior of the 32S and 34S isotopes over a broad range from high sulfate and organic carbon availability to substrate limitation using a constant fractionation factor. The new model developments are used to simulate a large-scale column study designed to replicate field scale conditions of an organic carbon (acetate) amended biostimulation experiment at the Old Rifle site in western Colorado. Results demonstrate an initial period of iron reduction that transitions to sulfate reduction, in agreement with field-scale behavior observed at the Old Rifle site. At the height of sulfate reduction, effluent sulfate concentrations decreased to 0.5 mM from an influent value of 8.8 mM over the 100 cm flow path, and thus were enriched in sulfate δ34S from 6.3‰ to 39.5‰. The reactive transport model accurately reproduced the measured enrichment in δ34S of both the reactant (sulfate) and product (sulfide) species of the reduction reaction using a single fractionation factor of 0.987 obtained independently from field-scale measurements. The model also accurately simulated the accumulation and δ34S signature of solid phase elemental sulfur over the duration of the experiment, providing a new tool to predict the isotopic signatures associated with reduced mineral pools

  2. Highly accurate potential energy surface, dipole moment surface, rovibrational energy levels, and infrared line list for {sup 32}S{sup 16}O{sub 2} up to 8000 cm{sup −1}

    SciTech Connect

    Huang, Xinchuan E-mail: Timothy.J.Lee@nasa.gov; Schwenke, David W.; Lee, Timothy J. E-mail: Timothy.J.Lee@nasa.gov

    2014-03-21

    A purely ab initio potential energy surface (PES) was refined with selected {sup 32}S{sup 16}O{sub 2} HITRAN data. Compared to HITRAN, the root-mean-squares error (σ{sub RMS}) for all J = 0–80 rovibrational energy levels computed on the refined PES (denoted Ames-1) is 0.013 cm{sup −1}. Combined with a CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), an infrared (IR) line list (denoted Ames-296K) has been computed at 296 K and covers up to 8000 cm{sup −1}. Compared to the HITRAN and CDMS databases, the intensity agreement for most vibrational bands is better than 85%–90%. Our predictions for {sup 34}S{sup 16}O{sub 2} band origins, higher energy {sup 32}S{sup 16}O{sub 2} band origins and missing {sup 32}S{sup 16}O{sub 2} IR bands have been verified by most recent experiments and available HITRAN data. We conclude that the Ames-1 PES is able to predict {sup 32/34}S{sup 16}O{sub 2} band origins below 5500 cm{sup −1} with 0.01–0.03 cm{sup −1} uncertainties, and the Ames-296K line list provides continuous, reliable and accurate IR simulations. The K{sub a}-dependence of both line position and line intensity errors is discussed. The line list will greatly facilitate SO{sub 2} IR spectral experimental analysis, as well as elimination of SO{sub 2} lines in high-resolution astronomical observations.

  3. Evaporation residue corss sections for {sup 32}S + {sup 184}W

    SciTech Connect

    Back, B.B.; Blumenthal, D.J.; Davids, C.N.

    1995-08-01

    We recently measured evaporation residue cross sections for the {sup 32}S + {sup 184}W system over a range of beam energies using the Argonne Fragment Mass Analyzer (FMA). Absolute cross sections were obtained on the basis of the recent determination of the transmission probability through the FMA of heavy, slow-moving reaction products. The measurements were carried out using {sup 32}S-beams from the ATLAS superconducting linac at Argonne. Beam energies of 165, 174, 185, 195, 205, 215, 225, 236, 246, and 257 MeV were used. The sliding-seal target chamber is used to allow for measurements at finite angles.

  4. {sup 33}S for Neutron Capture Therapy: Nuclear Data for Monte Carlo Calculations

    SciTech Connect

    Porras, I.; Sabaté-Gilarte, M.; Praena, J.; Quesada, J.M.; Esquinas, P.L.

    2014-06-15

    A study of the nuclear data required for the Monte Carlo simulation of boron neutron capture therapy including the {sup 33}S isotope as an enhancer of the dose at small depths has been performed. In particular, the controversy on the available data for the {sup 33}S(n, α) cross section will be shown, which motivates new measurements. In addition to this, kerma factors for the main components of tissue are calculated with the use of fitting functions. Finally, we have applied these data to a potential neutron capture treatment with boron and sulfur addition to tissue in which part of the hydrogen atoms are replaced by deuterium, which improves the procedure.

  5. Analysis of 34S in Individual Organic Compounds by Coupled GC-ICP-MS

    NASA Astrophysics Data System (ADS)

    Sessions, A. L.; Amrani, A.; Adkins, J. F.

    2009-12-01

    The abundances of 2H, 13C, and 15N in organic compounds have been extremely useful in many aspects of biogeochemistry. While sulfur plays an equally important role in many earth-surface processes, the isotopes of sulfur in organic matter have not been extensively employed in large part because there has been no direct route to the analysis of 34S in individual organic compounds. To remedy this, we have developed a highly sensitive and robust method for the analysis of 34S in individual organic compounds by coupled gas chromatography (GC) and multicollector inductively-coupled plasma mass spectrometry (ICP-MS). Isobaric interference from O2+ is minimized by employing dry plasma conditions, and is cleanly resolved at all masses using medium resolution on the Thermo Neptune ICP-MS. Correction for mass bias is accomplished using standard-sample bracketing with peaks of SF6 reference gas. The precision of measured δ34S values approaches 0.1‰ for analytes containing >40 pmol S, and is better than 0.5‰ for those containing as little as 6 pmol S. External accuracy is better than 0.3‰. Integrating only the center of chromatographic peaks, rather than the entire peak, offers significant gain in precision and chromatographic resolution with minimal effect on accuracy, but requires further study for verification as a routine method. Coelution of organic compounds that do not contain S can cause degraded analytical precision and accuracy. As a demonstration of the potential for this new method, we will present data from 3 sample types: individual organosulfur compounds from crude oil, dimethyl sulfide from seawater, and trace H2S from bacterial culture headspace.

  6. Optical properties of As33S67-xSex bulk glasses studied by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Orava, J.; Šik, J.; Wágner, T.; Frumar, M.

    2008-04-01

    Variable angle spectroscopic ellipsometry (VASE) was employed to study the optical properties of As33S67-xSex (x =0, 17, 33.5, 50, and 67at.%) bulk glasses in the UV-vis-NIR (near infrared) spectral region for photon energies from 0.54to4.13eV (photon wavelengths from 2300to300nm). For data analysis, we employed Tauc-Lorentz (TL) dispersion model in the entire measured near bandgap spectral region and standard Cauchy dispersion model in the spectral region below the bandgap. With increasing Se content (x) in the bulk glass, we observed a linear decrease in optical bandgap energy Egopt from 2.52±0.02eV for As33S67 to 1.75±0.01eV for As33Se67 and linear increase in refractive index nTL in the NIR spectral region, e.g., at 0.80eV from 2.327 for As33S67 to 2.758 for As33Se67. The amplitude A decreased with increasing Se content. The peak transition energy E0 and broadening C had a maximum value for x =33.5at.% and systematically decreased for higher S or Se content in glasses. Our study showed that TL model is suitable to describe dielectric functions of studied chalcogenide bulk glasses in the broad spectral region. The bulk glasses had a higher refractive index compared to thin films of corresponding composition. The bulk glasses with high S content had higher value of optical bandgap energy than was previously reported for thin films. The optical bandgap energy of glasses with higher Se content was very similar to the thin films.

  7. Charged particle spectra in [sup 32]S + [sup 32]S interactions at 200 GeV/nucleon from CCD-imaged nuclear collisions in a streamer chamber

    SciTech Connect

    Teitelbaum, L.P.

    1992-04-01

    We have measured the transverse momentum spectra 1/p[sub T] dN/dp[sub T] and rapidity distributions dN/dy of negatively charged hadrons and protons for central [sup 32]S + [sup 32]S interactions at 200 GeV/nucleon incident energy. The negative hadron dN/dy distribution is too broad to be accounted for by thermal models which demand isotropic particle emission. It is compatible with models which emphasize longitudinal dynamics, by either a particle production mechanism, as in the Lund fragmentation model, or by introducing one-dimensional hydrodynamic expansion, as in the Landau model. The proton dN/dy distribution, although showing no evidence for a peak in the target fragmentation region, exhibits limited nuclear stopping power. We estimate the mean rapidity shift of participant target protons to be [Delta]y [approximately] 1.5, greater than observed for pp collisions, less than measured in central pA collisions, and much less than would be observed for a single equilibrated fireball at midrapidity. Both the negative hadron and proton dN/dy distributions can be fit by a symmetric Landau two-fireball model. Although the spectrum possesses a two-component structure, a comparison to pp data at comparable center-of-mass energy shows no evidence for enhanced production at low p[sub T]. The two-component structure can be explained by a thermal and chemical equilibrium model which takes into account the kinematics of resonance decay. Using an expression motivated by longitudinal expansion we find the same temperature for both the protons and negative hadrons at freezeout, T[sub f] [approximately] 170 MeV. We conclude that the charged particle spectra of negative hadrons and protons can be accommodated in a simple collision picture of limited nuclear stopping, evolution through a state of thermal equilibrium, followed by longitudinal hydrodynamic expansion until freezeout.

  8. Charged particle spectra in {sup 32}S + {sup 32}S interactions at 200 GeV/nucleon from CCD-imaged nuclear collisions in a streamer chamber

    SciTech Connect

    Teitelbaum, L.P.

    1992-04-01

    We have measured the transverse momentum spectra 1/p{sub T} dN/dp{sub T} and rapidity distributions dN/dy of negatively charged hadrons and protons for central {sup 32}S + {sup 32}S interactions at 200 GeV/nucleon incident energy. The negative hadron dN/dy distribution is too broad to be accounted for by thermal models which demand isotropic particle emission. It is compatible with models which emphasize longitudinal dynamics, by either a particle production mechanism, as in the Lund fragmentation model, or by introducing one-dimensional hydrodynamic expansion, as in the Landau model. The proton dN/dy distribution, although showing no evidence for a peak in the target fragmentation region, exhibits limited nuclear stopping power. We estimate the mean rapidity shift of participant target protons to be {Delta}y {approximately} 1.5, greater than observed for pp collisions, less than measured in central pA collisions, and much less than would be observed for a single equilibrated fireball at midrapidity. Both the negative hadron and proton dN/dy distributions can be fit by a symmetric Landau two-fireball model. Although the spectrum possesses a two-component structure, a comparison to pp data at comparable center-of-mass energy shows no evidence for enhanced production at low p{sub T}. The two-component structure can be explained by a thermal and chemical equilibrium model which takes into account the kinematics of resonance decay. Using an expression motivated by longitudinal expansion we find the same temperature for both the protons and negative hadrons at freezeout, T{sub f} {approximately} 170 MeV. We conclude that the charged particle spectra of negative hadrons and protons can be accommodated in a simple collision picture of limited nuclear stopping, evolution through a state of thermal equilibrium, followed by longitudinal hydrodynamic expansion until freezeout.

  9. An ab initio variationally computed room-temperature line list for (32)S(16)O3.

    PubMed

    Underwood, Daniel S; Tennyson, Jonathan; Yurchenko, Sergei N

    2013-07-01

    Ab initio potential energy and dipole moment surfaces are computed for sulfur trioxide (SO3) at the CCSD(T)-F12b level of theory with appropriate triple-zeta basis sets. The analytical representations of these surfaces are used, with a slight correction, to compute pure rotational and rotation-vibration spectra of (32)S(16)O3 using the variational nuclear motion program TROVE. The calculations considered transitions in the region 0-4000 cm(-1) with rotational states up to J = 85. The resulting line list of 174,674,257 transitions is appropriate for modelling room temperature (32)S(16)O3 spectra. Good agreement is found with the observed infrared absorption spectra and the calculations are used to place the measured relative intensities on an absolute scale. A list of 10,878 experimental transitions is provided in a form suitable for inclusion in standard atmospheric and planetary spectroscopic databases. PMID:23579443

  10. Exploring quasifission characteristics for +232Th34S forming 266Sg

    NASA Astrophysics Data System (ADS)

    Prasad, E.; Wakhle, A.; Hinde, D. J.; Williams, E.; Dasgupta, M.; Evers, M.; Luong, D. H.; Mohanto, G.; Simenel, C.; Vo-Phuoc, K.

    2016-02-01

    Background: Fission fragments from heavy ion collisions with actinide nuclei show mass-asymmetric and mass-symmetric components. The relative probabilities of these two components vary rapidly with beam energy with respect to the capture barrier, indicating a strong dependence on the alignment of the deformed nucleus with the partner in the collisions. Purpose: To study the characteristics of the mass-asymmetric quasifission component by reproducing the experimental mass-angle distributions to investigate mass evolution and sticking times. Methods: Fission fragment mass-angle distributions were measured for the +232Th34S reaction. Simulations to match the measurements were made by using a classical phenomenological approach. Mass ratio distributions and angular distributions of the mass-asymmetric quasifission component were simultaneously fit to constrain the free parameters used in the simulation. Results: The mass-asymmetric quasifission component—predominantly originating from tip (axial) collisions with the prolate deformed 232Th —is found to be peaked near A =200 at all energies and center-of-mass angles. A Monte Carlo model using the standard mass equilibration time constant of 5.2 ×10-21 s predicts more symmetric mass splits. Three different hypotheses assuming (i) a mass halt at A =200 , (ii) a slower mass equilibration time, or (iii) a Fermi-type mass drift function reproduced the main experimental features. Conclusions: In tip collisions for the +232Th34S reaction, mass-asymmetric fission with A ˜200 is the dominant outcome. The average sticking time is found to be ˜7 ×10-21 s, independent of the scenario used for mass evolution.

  11. Soft photon production in central 200 GeV/nucleon {sup 32}S + Au collisions

    SciTech Connect

    Aggarwal, M.M.; Bhatia, V.S.; Mittra, I.S.; Angelis, A.L.; Doenni, P.; Durieux, E.; Foka, P.; Izycki, M.; Kalechofsky, H.; Martin, M.; Naef, H.; Rosselet, L.; Rubio, J.M.; Solomey, N.; Ster, A.; Antonenko, V.; Fokin, S.; Ippolitov, M.; Karadjev, K.; Lebedev, A.; Manko, V.; Nikolaev, S.; Vinogradov, A.; Awes, T.C.; Obenshain, F.E.; Plasil, F.; Saini, S.; Young, G.R.; Badyal, S.K.; Devanand, L.; Kachroo, S.; Rao, N.K.; Sambyal, S.S.; Barlag, C.; Blume, C.; Bock, D.; Bohne, E.; Bucher, D.; Claussen, A.; Clewing, G.; Glasow, R.; Hartig, M.; Hoelker, G.; Kampert, K.; Langheinrich, J.; Peitzmann, T.; Santo, R.; Stueken, D.; Weber, S.; Bhalla, K.B.; Gupta, S.K.; Kumar, V.; Lokanathan, S.; Mookerjee, S.; Raniwala, S.; Buijs, A.; Geurts, F.; Kamermans, R.; Twenhoefel, C.; van Eijndhoven, N.; van Heeringen, E.; Chattopadhyay, S.; Das, A.C.; Dutta Majumdar, M.R.; Ganti, M.S.; Ghosh, T.K.; Nayak, S.K.; Sinha, B.C.; Trivedi, M.D.; Viyogi, Y.P.; Garpman, S.; Gustafsson, H.; Nystrand, J.; Oskarsson, A.; Otterlund, I.; Soederstroem, K.; Stenlund, E.; Gutbrod, H.H.; Kolb, B.W.; Langbein, I.; Purschke, M.; Roters, B.; Schmidt, H.R.; Sorensen, S.P.; Steinhaeuser, P.; Xiaochun, H.; Loehner, H.; Siemssen, R.; Slegt, S.

    1997-08-01

    Inclusive photons of low transverse momenta have been measured in 200 GeV/nucleon {sup 32}S+Au collisions at the CERN SPS. Data were taken in the WA93 experiment using a small acceptance BGO detector with longitudinal segmentation. The results are compared to WA80 measurements for the same system and results from hadron decay calculations. An excess of soft photons over the expectations from neutral meson decays is observed. {copyright} {ital 1997} {ital The American Physical Society}

  12. The stellar populations of M33's outer regions - IV. Inflow history and chemical evolution

    NASA Astrophysics Data System (ADS)

    Barker, Michael K.; Sarajedini, A.

    2008-10-01

    We have modelled the observed colour-magnitude diagram (CMD) at one location in M33's outskirts under the framework of a simple chemical evolution scenario which adopts instantaneous and delayed recycling for the nucleosynthetic products of Type II and Ia supernovae. In this scenario, interstellar gas forms stars at a rate modulated by the Kennicutt-Schmidt relation and gas outflow occurs at a rate proportional to the star formation rate (SFR). With this approach, we put broad constraints on the role of gas flows during this region's evolution and compare its [α/Fe] versus [Fe/H] relation with that of other Local Group systems. We find that models with gas inflow are significantly better than the closed-box model at reproducing the observed distribution of stars in the CMD. The best models have a majority of gas inflow taking place in the last 7 Gyr, and relatively little in the last 3 Gyr. These models predict most stars in this region to have [α/Fe] ratios lower than the bulk of the Milky Way's halo. The predictions for the present-day SFR, gas mass and oxygen abundance compare favourably to independent empirical estimates. Our results paint a picture in which M33's outer disc formed from the protracted inflow of gas over several Gyr with at least half of the total inflow occurring since z ~ 1.

  13. Detangling the Web of Sulfur Metabolisms in Santa Barbara Basin with High-Resolution δ34S and Genomic Profiles

    NASA Astrophysics Data System (ADS)

    Raven, M. R.; Adkins, J. F.; Sessions, A. L.; Dawson, K.; Connon, S. A.; Orphan, V. J.

    2014-12-01

    Sulfur metabolisms are major drivers of organic matter remineralization and microbial growth in marine sediments. Sulfur-isotope systematics are particularly powerful for interrogating metabolic processes in these systems due to the large sulfur-isotope fractionations associated with bacterial sulfate reduction (BSR) and some other metabolic reactions. Recent analytical advancements have made it possible to measure δ34S values of very small samples (>50 nmol), including aqueous sulfate and sulfide as well as pyrite, elemental sulfur, and multiple fractions of sedimentary organic matter. We have generated comprehensive 2.5 cm-resolution depth profiles of these sulfur pools over a 2-m core from Santa Barbara Basin, a sub-oxic environment off the California coast. We find that the porewater sulfide δ34S values appear to be strongly influenced by anaerobic sulfide oxidation and sulfur disproportionation in addition to BSR. These sulfur-isotope signals can be tracked over the course of several thousand years of sediment diagenesis, moving from the oxic-anoxic transition at the sediment-water interface to the sulfate-methane transition zone in deeper sediments. Shifts in δ34S relationships among sulfur pools correlate with changes in microbial community composition as shown in TAG genomic data, which supports the existence of the metabolisms indicated by δ34S profiles. Our results suggest that the existence and activity of multiple microbial communities and coexisting sulfur metabolisms have the potential to be recorded in sedimentary δ34S records.

  14. Tracking selenium behaviour in chalk aquifer (northern France): Sr and 34S-sulphates isotopes constraints.

    NASA Astrophysics Data System (ADS)

    Cary, Lise; Benabderraziq, Hind; Elkhattabi, Jamal; Parmentier, Marc; Gourcy, Laurence; Négrel, Philippe

    2014-05-01

    Groundwaters in parts of the Paris Basin (France) are facing increasing selenium (Se) contents that can exceed the drinking water limit of 10 μg/L according to the European Framework Directive in the field of water policy (2000/60/EC). To better understand the groundwater origins and the selenium dynamics, the water chemistry of the Chalk aquifer supplying drinkable water to Lille city was studied. This area is submitted to quantitative and qualitative pressure from industrial, urban and agriculture origins. An integrated study was settled to determine the water sources and dynamics of elements, with a focus on Se. After a large chemical characterisation of the groundwater chemistry in the four field wells, a monthly monitoring was held in four wells and in the Deûle channel. Chemical analysis of major and trace elements, stable isotopes (δ18O, δ2H), strontium isotopes, and δ34S and δ18O of sulphates were realised. The chemical composition of solids sampled at various depths at vicinity of the four wells was also analysed. The specific geochemical signature of groundwater as revealed by Sr isotopes, in addition to element concentrations ratios like Mg/Sr and Se/Sr, highlighted mixture of three main groundwaters bodies: (1) the upstream groundwaters in the recharge area with the most radiogenic 87Sr/86Sr isotopic signature; (2) the confined groundwaters with high Sr concentrations due to water-rock interactions and the lowest 87Sr/86Sr isotopic signature close to the one of the chalk in Paris and London basins; (3) the Se-rich formations of Tertiary and Quaternary. The contents of Se, mainly present as SeV I (and locally as SeIV ), displayed spatial and temporal disparities that can be explained by geological and hydrogeological conditions. Se-rich clayed sediments originating from the dismantling of Se-rich tertiary formations (i.e. Ypresian) overlay the chalk formation and can be found in saturated conditions depending of the water table level. Oxidation of

  15. Sedimentary pyrite δ34S differs from porewater sulfide in Santa Barbara Basin: Proposed role of organic sulfur

    NASA Astrophysics Data System (ADS)

    Raven, Morgan Reed; Sessions, Alex L.; Fischer, Woodward W.; Adkins, Jess F.

    2016-08-01

    Santa Barbara Basin sediments host a complex network of abiotic and metabolic chemical reactions that knit together the carbon, sulfur, and iron cycles. From a 2.1-m sediment core collected in the center of the basin, we present high-resolution profiles of the concentrations and isotopic compositions of all the major species in this system: sulfate, sulfide (∑H2S), elemental sulfur (S0), pyrite, extractable organic sulfur (OS), proto-kerogen S, total organic and dissolved inorganic carbon, and total and reducible iron. Below 10 cm depth, the core is characterized by low apparent sulfate reduction rates (<0.01 mM/yr) except near the sulfate-methane transition zone. Surprisingly, pyrite forming in shallow sediments is ∼30‰ more 34S-depleted than coexisting ∑H2S in porewater. S0 has the same strongly 34S-depleted composition as pyrite where it forms near the sediment-water interface, though not at depth. This pattern is not easily explained by conventional hypotheses in which sedimentary pyrite derives from abiotic reactions with porewater ∑H2S or from the products of S0 disproportionation. Instead, we propose that pyrite formation in this environment occurs within sulfate reducing microbial aggregates or biofilms, where it reflects the isotopic composition of the immediate products of bacterial sulfate reduction. Porewater ∑H2S in Santa Barbara Basin may be more 34S-enriched than pyrite due to equilibration with relatively 34S-enriched OS. The difference between OS and pyrite δ34S values would then reflect the balance between microbial sulfide formation and the abundance of exchangeable OS. Both OS and pyrite δ34S records thus have the potential to provide valuable information about biogeochemical cycles and redox structure in sedimentary paleoenvironments.

  16. The fusion-fission process in the reaction 34S +186W near the interaction barrier

    NASA Astrophysics Data System (ADS)

    Harca, I. M.; Dmitriev, S.; Itkis, J.; Kozulin, E. M.; Knyazheva, G.; Loktev, T.; Novikov, K.; Azaiez, F.; Gottardo, A.; Matea, I.; Verney, D.; Chubarian, G.; Hanappe, F.; Piot, J.; Schmitt, C.; Trzaska, W. H.; Vardaci, E.

    2015-02-01

    The reaction 34S +186W at Elab=160 MeV was investigated with the aim of diving into the features of the fusion-fission process. Gamma rays in coincidence with binary reaction fragments were measured using the high efficiency gamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometer for fission fragments (FF) registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. The coupling of the ORGAM and CORSET setups offers the unique opportunity of extracting details for characterizing the fusion-fission process and gives information regarding production of neutron-rich heavy nuclei. The FF-γ coincidence method is of better use then the γ - γ coincidence method when dealing with low statistic measurements and also offers the opportunity to precisely correct the Dopler shift for in-flight emitted gamma rays. Evidence of symmetric and asymmetric fission modes were observed in the mass and TKE distributions, occurring due to shell effects in the fragments. Coincident measurements allow for discrimination between the gamma rays by accepting a specific range within the mass distribution of the reaction products. Details regarding the experimental setup, methods of processing the acquisitioned data and preliminary results are presented.

  17. Stable isotope (13C, 15N and 34S) analysis of the hair of modern humans and their domestic animals.

    PubMed

    Bol, Roland; Pflieger, Christian

    2002-01-01

    Relationships between dietary status and recent migration were examined by delta(13)C, delta(15)N and delta(34)S analysis of hair samples from 43 modern humans living in a rural community in SW England. The isotopic content of 38 'local' hair samples was compared with that of five recently arrived individuals (from Canada, Chile, Germany and the USA). Hair samples from domestic animals (i.e. mainly cats, dogs, cows and horses) were analysed to examine the difference in delta(13)C, delta(15)N and delta(34)S values between herbivores and carnivores. Generally, modern human hair data from the triple stable isotope (delta(13)C, delta(15)N and delta(34)S) provided enough information to confirm the dietary status and origin of the individual subjects. The dietary intake was generally reflected in the animal hair delta(15)N and delta(13)C values, i.e. highest in the carnivores (cats). However, a non-local origin of food sources given to domesticated omnivores (i.e. dogs) was suggested by their hair delta(34)S values. PMID:12442295

  18. Significant human impact on the flux and δ(34)S of sulfate from the largest river in North America.

    PubMed

    Killingsworth, Bryan A; Bao, Huiming

    2015-04-21

    Riverine dissolved sulfate (SO4(2-)) flux and sulfur stable isotope composition (δ(34)S) yield information on the sources and processes affecting sulfur cycling on different spatial and temporal scales. However, because pristine preindustrial natural baselines of riverine SO4(2-) flux and δ(34)S cannot be directly measured, anthropogenic impact remains largely unconstrained. Here we quantify natural and anthropogenic SO4(2-) flux and δ(34)S for North America's largest river, the Mississippi, by means of an exhaustive source compilation and multiyear monitoring. Our data and analysis show that, since before industrialization to the present, Mississippi River SO4(2-) has increased in flux from 7.0 to 27.8 Tg SO4(2-) yr(-1), and in mean δ(34)S from -5.0‰, within 95% confidence limits of -14.8‰ to 4.1‰ (assuming normal distribution for mixing model input parameters), to -2.7 ± 1.6‰, reflecting an impressive footprint of bedrocks particular to this river basin and human activities. Our first-order modern Mississippi River sulfate partition is 25 ± 6% natural and 75% ± 6% anthropogenic sources. Furthermore, anthropogenic coal usage is implicated as the dominant source of modern Mississippi River sulfate, with an estimated 47 ± 5% and 13% of total Mississippi River sulfate due to coal mining and burning, respectively. PMID:25803121

  19. The 2p33s, 3p and 3d configurations of eight times ionized sulphur, S IX

    NASA Astrophysics Data System (ADS)

    Jupén, Christer; Engström, Lars

    1997-12-01

    The spectrum of eight times ionized sulphur, S IX, has been investigated in the wavelength region 690 to 960 Å by means of the beam-foil method. Twenty-three new lines have been identified as combinations between levels of the 2p33s, 3p and 3d configurations. Many of these lines have also recently been found in spectra of the solar corona recorded by the SOHO satellite. We have also identified 12 new lines between 47 and 55 Å as combinations between the 2s22p4 ground configuration and 2p33s and 3d. The new transitions combined with previously known data establish all 10 2p33s levels, 13 of the possible 28 3p levels and 34 out of 38 3d levels. The spectroscopic identifications are supported by isoelectronic extrapolations and by theoretical calculations.

  20. Silver photo-diffusion and photo-induced macroscopic surface deformation of Ge33S67/Ag/Si substrate

    NASA Astrophysics Data System (ADS)

    Sakaguchi, Y.; Asaoka, H.; Uozumi, Y.; Kondo, K.; Yamazaki, D.; Soyama, K.; Ailavajhala, M.; Mitkova, M.

    2016-08-01

    Ge-chalcogenide films show various photo-induced changes, and silver photo-diffusion is one of them which attracts lots of interest. In this paper, we report how silver and Ge-chalcogenide layers in Ge33S67/Ag/Si substrate stacks change under light exposure in the depth by measuring time-resolved neutron reflectivity. It was found from the measurement that Ag ions diffuse all over the matrix Ge33S67 layer once Ag dissolves into the layer. We also found that the surface was macroscopically deformed by the extended light exposure. Its structural origin was investigated by a scanning electron microscopy.

  1. Open system sulphate reduction in a diagenetic environment - Isotopic analysis of barite (δ34S and δ18O) and pyrite (δ34S) from the Tom and Jason Late Devonian Zn-Pb-Ba deposits, Selwyn Basin, Canada

    NASA Astrophysics Data System (ADS)

    Magnall, J. M.; Gleeson, S. A.; Stern, R. A.; Newton, R. J.; Poulton, S. W.; Paradis, S.

    2016-05-01

    Highly positive δ34S values in sulphide minerals are a common feature of shale hosted massive sulphide deposits (SHMS). Often this is attributed to near quantitative consumption of seawater sulphate, and for Paleozoic strata of the Selwyn Basin (Canada), this is thought to occur during bacterial sulphate reduction (BSR) in a restricted, euxinic water column. In this study, we focus on drill-core samples of sulphide and barite mineralisation from two Late Devonian SHMS deposits (Tom and Jason, Macmillan Pass, Selwyn Basin), to evaluate this euxinic basin model. The paragenetic relationship between barite, pyrite and hydrothermal base metal sulphides has been determined using transmitted and reflected light microscopy, and backscatter electron imaging. This petrographic framework provides the context for in-situ isotopic microanalysis (secondary ion mass spectrometry; SIMS) of barite and pyrite. These data are supplemented by analyses of δ34S values for bulk rock pyrite (n = 37) from drill-core samples of un-mineralised (barren), siliceous mudstone, to provide a means by which to evaluate the mass balance of sulphur in the host rock. Three generations of barite have been identified, all of which pre-date hydrothermal input. Isotopically, the three generations of barite have overlapping distributions of δ34S and δ18O values (+22.5‰ to +33.0‰ and +16.4‰ to +18.3‰, respectively) and are consistent with an origin from modified Late Devonian seawater. Radiolarian tests, enriched in barium, are abundant within the siliceous mudstones, providing evidence that primary barium enrichment was associated with biologic activity. We therefore propose that barite formed following remobilisation of productivity-derived barium within the sediment, and precipitated within diagenetic pore fluids close to the sediment water interface. Two generations of pyrite are texturally associated with barite: framboidal pyrite (py-I), which has negative δ34S values (-23‰ to -28

  2. Energies of molecular structures in 12C,16O,20Ne,24Mg, and 32S

    NASA Astrophysics Data System (ADS)

    Royer, G.; Ramasamy, G.; Eudes, P.

    2015-11-01

    The energies of the 12C,16O,20Ne,24Mg, and 32S 4 n nuclei have been determined within a generalized liquid drop model and assuming different planar and three-dimensional shapes of the α molecules: linear chain, triangle, square, tetrahedron, pentagon, trigonal bipyramid, square pyramid, hexagon, octahedron, octagon, and cube. The potential barriers governing the entrance and decay channels via α absorption or emission as well as more symmetric binary and ternary reactions have been compared. The rms radii of the linear chains differ from the experimental rms radii of the ground states. The binding energies of the three-dimensional shapes at the contact point are higher than the ones of the planar configurations. The α particle plus A-4 daughter configuration leads always to the lowest potential barrier. The binding energy can be reproduced within the sum of the binding energy of n α particles plus the number of bonds multiplied by 2.4 MeV or by the sum of the binding energies of one α particle and the daughter nucleus plus the Coulomb energy and the proximity energy.

  3. Modeling and measuring intracellular fluxes of secreted recombinant protein in Pichia pastoris with a novel 34S labeling procedure

    PubMed Central

    2011-01-01

    Background The budding yeast Pichia pastoris is widely used for protein production. To determine the best suitable strategy for strain improvement, especially for high secretion, quantitative data of intracellular fluxes of recombinant protein are very important. Especially the balance between intracellular protein formation, degradation and secretion defines the major bottleneck of the production system. Because these parameters are different for unlimited growth (shake flask) and carbon-limited growth (bioreactor) conditions, they should be determined under "production like" conditions. Thus labeling procedures must be compatible with minimal production media and the usage of bioreactors. The inorganic and non-radioactive 34S labeled sodium sulfate meets both demands. Results We used a novel labeling method with the stable sulfur isotope 34S, administered as sodium sulfate, which is performed during chemostat culivations. The intra- and extracellular sulfur 32 to 34 ratios of purified recombinant protein, the antibody fragment Fab3H6, are measured by HPLC-ICP-MS. The kinetic model described here is necessary to calculate the kinetic parameters from sulfur ratios of consecutive samples as well as for sensitivity analysis. From the total amount of protein produced intracellularly (143.1 μg g-1 h-1 protein per yeast dry mass and time) about 58% are degraded within the cell, 35% are secreted to the exterior and 7% are inherited to the daughter cells. Conclusions A novel 34S labeling procedure that enables in vivo quantification of intracellular fluxes of recombinant protein under "production like" conditions is described. Subsequent sensitivity analysis of the fluxes by using MATLAB, indicate the most promising approaches for strain improvement towards increased secretion. PMID:21703020

  4. Velocity spectra and angular distributions of evaporation residues from sup 32 S + sup 12 C at 145 MeV

    SciTech Connect

    Arena, N.; Cavallaro, S.; Femino', S.; Figuera, P.; Pirrone, S.; Porto, F.; Sambataro, S. )

    1991-11-01

    Velocity spectra and angular and mass distributions for the evaporation residues of the {sup 32}S+{sup 12}C system at {ital E}{sup 32}S=145 MeV in the angular range 3{degree}{le}{var theta}{sub {ital L}}{le}12{degree} have been measured. In order to separate compound nucleus evaporation residues from other heavy reaction products, a kinematic analysis based on simple statistical assumptions relative to the velocity spectra was performed. The structures in the mass distribution are compared with the LILITA code predictions. The fusion excitation function of the existing results is compared with theoretical models. The total reaction cross section has been extracted by means of the modified sum of differences method.

  5. The stable isotopic composition of a phosphorite deposit: δ13C, δ34S, and δ18O

    USGS Publications Warehouse

    Piper, D.Z.; Kolodny, Y.

    1987-01-01

    The stable isotopes of carbon and sulfur in a major marine sedimentary phosphate deposit from the northwestern United States (the Phosphoria Formation of Permian age) characterize the chemical properties of the depositional environment. The δ34S and δ13C analyses suggest deposition under conditions of variable redox from a solution the acidity of which was controlled by reaction with carbonate rocks and exchange with seawater. The δ18O concentration of apetite indicates phosphatization in a shallow sea, during three glacial and intervening interglacial stages. These data tend to corroborate the interpretation of field studies by others, that the apatite formed on a continental shelf in an area of intense oceanic upwelling during several episodes of sea level change. 

  6. 16O + 16O molecular structures of positive- and negative-parity superdeformed bands in 34S

    NASA Astrophysics Data System (ADS)

    Taniguchi, Yasutaka

    2016-05-01

    The structures of excited states in 34S are investigated using the antisymmetrized molecular dynamics and generator coordinate method(GCM). The GCM basis wave functions are calculated via energy variation with a constraint on the quadrupole deformation parameter β. By applying the GCM after parity and angular momentum projections, the coexistence of two positive- and one negative-parity super de formed(SD) bands are predicted, and low-lying states and other deformed bands are obtained. The SD bands have structures of 16O + 16O + two valence neutrons in molecular orbitals around the two 16O cores in a cluster picture. The configurations of the two valence neutrons are δ2 and π2 for the positive-parity SD bands and π1δ1 for the negative parity SD band.

  7. Competition between fusion-fission and quasifission processes in the {sup 32}S+{sup 184}W reaction

    SciTech Connect

    Zhang, H. Q.; Zhang, C. L.; Lin, C. J.; Liu, Z. H.; Yang, F.; Nasirov, A. K.; Mandaglio, G.; Manganaro, M.; Giardina, G.

    2010-03-15

    The angular distributions of fission fragments for the {sup 32}S+{sup 184}W reaction at center-of-mass energies of 118.8, 123.1, 127.3, 131.5, 135.8, 141.1, and 144.4 MeV are measured. The experimental fission excitation function is obtained. The anisotropy (A{sub exp}) is found by extrapolating each fission fragment angular distribution. The measured fission cross sections of the {sup 32}S+{sup 182,184}W reaction are decomposed into fusion-fission, quasifission, and fast-fission contributions by the dinuclear system model (DNS). The angular momentum distributions of the dinuclear system and compound nucleus calculated by the DNS model are used to reproduce the experimental capture and fusion excitation functions for both reactions and quantities K{sub 0}{sup 2}, , and A{sub exp}, which characterize angular distributions of the fission products at the considered range of beam energy. The total evaporation residue excitation function for the {sup 32}S+{sup 184}W reaction calculated in the framework of the advanced statistical model is close to the available experimental data only up to about E{sub c.m.}approx =160 MeV. The underestimation of the experimental data at high excitation energies E{sub c.m.}>160 MeV is explained by the fact that the statistical model cannot reproduce the cross section of evaporation residues formed by the nonequilibrium mechanism, that is, without formation of the compound nucleus in the statistical equilibrium state.

  8. Reaction mechanisms in {sup 24}Mg+{sup 12}C and {sup 32}S+{sup 24}Mg

    SciTech Connect

    Beck, C.; Sanchez i Zafra, A.; Papka, P.; Thummerer, S.; Azaiez, F.; Courtin, S.; Curien, D.; Dorvaux, O.; Lebhertz, D.; Nourreddine, A.; Rousseau, M.; Oertzen, W. von; Gebauer, B.; Kokalova, Tz.; Wheldon, C.; De Angelis, G.; Gadea, A.; Lenzi, S.; Napoli, D. R.; Szilner, S.

    2009-03-04

    The occurrence of 'exotic' shapes in light N = Z{alpha}-like nuclei is investigated for {sup 24}Mg+{sup 12}C and {sup 32}S+{sup 24}Mg. Various approaches of superdeformed and hyperdeformed bands associated with quasimolecular resonant structures with low spin are presented. For both reactions, exclusive data were collected with the Binary Reaction Spectrometer in coincidence with EUROBALL IV installed at the VIVITRON Tandem facility of Strasbourg. Specific structures with large deformation were selectively populated in binary reactions and their associated {gamma}-decays studied. The analysis of the binary and ternary reaction channels is discussed.

  9. Factorial correlator study in {sup 32}S-Ag/Br interaction at 200{ital A} GeV

    SciTech Connect

    Ghosh, D.; Lahiri, M.; Deb, A.; Das, S.; Purkait, K.; Biswas, B.; Roychoudhury, J.; Chatterjee, R.; Zafri, A.K.

    1995-10-01

    In this paper we present an analysis of our {sup 32}S-induced interaction data at 200{ital A} GeV in terms of factorial correlators. The correlated moments are found to increase with decreasing bin-bin separation, {ital D}. This increase follows a power law within the region {ital D}{le}1. Bin-size independence of the factorial correlators is observed for the values of {ital D}=0.4 and {ital D}=0.8. Our data are consistent with the dimension-independent scaling relation proposed by Seixas, which gives a way out of the ``intermittent``-``nonintermittent`` ambiguity.

  10. Precision Penning Trap Mass Spectrometry of ^32S, ^84,86Kr and ^129,132Xe

    NASA Astrophysics Data System (ADS)

    Redshaw, Matthew

    2005-05-01

    Using a phase coherent technique to measure the cyclotron frequency of single ions in a Penning trap [1], we have performed mass measurements on ^32S and the two most abundant krypton and xenon isotopes ^84Kr, ^86Kr, ^ 129Xe and ^132Xe, to relative precisions of 0.1 ppb. This is a factor of ˜10-100 improvement in precision over current values [2]. [1] M.P. Bradley, J.V. Porto, S. Rainville, J.K. Thompson, and D.E. Pritchard, PRL 83, 4510 (1999). [2] G. Audi, A.H. Wapstra, and C. Thibault, Nucl Phys A729, 337 (2003).

  11. The Study of the Groundwater by Using the 34S and 18O of the Sulphates-S18O4 Isotopes

    NASA Astrophysics Data System (ADS)

    Awad, Sadek

    The stable isotope of the sulphur atom (34S) and the 18O of the sulphates (S18O4) give information about the type of the mineralisation of the groundwater existing during the water seepage. The decrease of the concentrations in dissolved SO42- (meq/L) versus the increase of δ18O (‰ vs. SMOW) of the sulphates (S18O42-) confirms a partial reduction of the dissolved sulphates in the water. The Under-saturated waters versus the gypsum do not cause the precipitations of the sulphates. The study of δ34S (‰ CD) vs. Cl- (mg/L) indicates high variations in δ34S (‰ CD) for weak difference in the Cl- (mg/L) content, this is due to the reduction of the dissolved sulphates. Concerning the Jurassic water in Lebanon, an oxidation of the sulphide can take place.

  12. The fusion-fission process in the reaction {sup 34}S+{sup 186}W near the interaction barrier

    SciTech Connect

    Harca, I. M.; Dmitriev, S.; Itkis, J.; Kozulin, E. M.; Knyazheva, G.; Loktev, T.; Novikov, K.; Azaiez, F.; Gottardo, A.; Matea, I.; Verney, D.; Hanappe, F.; Piot, J.; Schmitt, C.; Vardaci, E.

    2015-02-24

    The reaction {sup 34}S+{sup 186}W at E{sub lab}=160 MeV was investigated with the aim of diving into the features of the fusion-fission process. Gamma rays in coincidence with binary reaction fragments were measured using the high efficiency gamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometer for fission fragments (FF) registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. The coupling of the ORGAM and CORSET setups offers the unique opportunity of extracting details for characterizing the fusion-fission process and gives information regarding production of neutron-rich heavy nuclei. The FF–γ coincidence method is of better use then the γ – γ coincidence method when dealing with low statistic measurements and also offers the opportunity to precisely correct the Dopler shift for in-flight emitted gamma rays. Evidence of symmetric and asymmetric fission modes were observed in the mass and TKE distributions, occurring due to shell effects in the fragments. Coincident measurements allow for discrimination between the gamma rays by accepting a specific range within the mass distribution of the reaction products. Details regarding the experimental setup, methods of processing the acquisitioned data and preliminary results are presented.

  13. Polarization and binding effects in K-shell ionization by /sup 16/O and /sup 32/S ions

    SciTech Connect

    Sigaud, G.M.; Montenegro, E.C.; Seidel, J.; Dost, M.

    1986-11-01

    The theoretical model of Montenegro and Sigaud is used for the description of the experimental total K-shell ionization cross sections for 2.2-MeV/u /sup 16/O and /sup 32/S on 24 targets from /sub 21/Sc to /sub 83/Bi obtained by Seidel et al. The predictions of the model, which considers both binding and static polarization effects within the framework of adiabatic perturbation theory, are very good for the majority of the measured data in the region of validity of the model. The electron-capture process that can contribute in the region of the largest values of relative velocity xi/sub K/ is also analyzed.

  14. 17 CFR 259.405 - Form U-33-S, for annual reports pursuant to Rule 57(b) (§ 250.57 of this chapter).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... citations affecting Form U-33-S, see the List of CFR Sections Affected, which appears in the Finding Aids... HOLDING COMPANY ACT OF 1935 Forms for Statements and Reports From Nonregistered (Exempt) Companies § 259... be filed by a public utility company that is an associate of one or more foreign utility...

  15. 17 CFR 259.405 - Form U-33-S, for annual reports pursuant to Rule 57(b) (§ 250.57 of this chapter).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... citations affecting Form U-33-S, see the List of CFR Sections Affected, which appears in the Finding Aids... HOLDING COMPANY ACT OF 1935 Forms for Statements and Reports From Nonregistered (Exempt) Companies § 259... be filed by a public utility company that is an associate of one or more foreign utility...

  16. Direct measurement of several resonance strengths and energies in 34S(α , γ) 38 Ar within the T = 2 . 2 GK Gamow window with DRAGON

    NASA Astrophysics Data System (ADS)

    Connolly, D.; O'Malley, P.; Akers, C.; Chen, A. A.; Christian, G.; Davids, B.; Erikson, L. E.; Fallis, J.; Fulton, B. R.; Greife, U.; Hager, Ulrike; Hutcheon, D. A.; Ilyushkin, S.; Laird, A. M.; Mahl, A.; Ruiz, C.

    2015-10-01

    Radiative α capture on 34S can impact nucleosynthesis in several astrophysical environments, including oxygen burning, explosive oxygen burning (Type II supernovae), and Type Ia supernovae. However, there exist discrepancies in the literature for the resonance strengths of two strong resonances within the Gamow window for oxygen burning temperatures (E0 +/- Δ / 2 = 3183 +/- 897 keV at T = 2 . 2 GK). Previous measurements suffered from systematic uncertainties inherent in the experimental technique. Furthermore, there are several states in 38Ar in the energy range of interest for which no 34S + α resonance strength/energy measurements have been performed. This measurement was performed in inverse kinematics at the DRAGON recoil separator at TRIUMF in BC, Canada. DRAGON's experimental technique allows direct measurement of quantities such as stopping power and resonance energy, alleviating the need for external inputs and reducing uncertainty. This talk will discuss DRAGON's experimental technique, analysis methods and results.

  17. Tracking photosynthetic sulfide oxidation in a meromictic lake using sulfate δ34S and δ18O

    NASA Astrophysics Data System (ADS)

    Gilhooly, W. P.; Reinhard, C.; Lyons, T. W.; Glass, J. B.

    2012-12-01

    Phototrophic sulfur bacteria oxidize sulfide and fix carbon dioxide in the presence of sunlight without producing oxygen. Environmental conditions in the Paleo- and Mesoproterozoic, when atmospheric oxygen concentrations were at low levels and portions of the oceans were anoxic and sulfidic (euxinic), were conducive to widespread carbon fixation by anoxygenic photosynthesis. This pathway may have helped sustain euxinic conditions in the Proterozoic water column. With limited organic biomarker and geochemical evidence for widespread production of anoxygenic phototrophs, however, additional proxies are needed to fingerprint paleoecological and biogeochemical signals associated with photic zone euxinia. Paired δ34S and δ18O from ancient sulfates (gypsum, barite, or CAS) may offer an added constraint on the history and ecological dominance of photosynthetic S-oxidation. Sulfate-oxygen can fractionate during sulfate reduction, but the extent of isotopic enrichment is controlled either by kinetic isotope effects imparted during intracellular enzymatic steps or equilibrium oxygen exchange with ambient water. An improved understanding of these processes can be gained from modern natural environments. Mahoney Lake is a density-stratified lake located within the White Lake Basin of British Columbia. The euxinic water column supports a dense plate of purple sulfur bacteria (Amoebobacter purpureus) that thrives where free sulfide intercepts the photic zone at ~7 m water depth. We analyzed the isotopic composition of sulfate (δ34SSO4 and δ18OSO4), sulfide (δ34SH2S), and water (δ18OH2O) to track the potentially coupled processes of dissimilatory sulfate reduction and phototrophic sulfide oxidation within this meromictic lake. Large isotopic offsets observed between sulfate and sulfide within the monimolimnion (δ34SSO4-H2S = 51‰) and within pore waters along the oxic margin (δ34SSO4-H2S >50‰) are consistent with sulfate reduction in both the sediments and the anoxic

  18. A compilation of information on the {sup 32}S(p, {gamma}){sup 33}Cl reaction and properties of excited levels in {sup 33}Cl

    SciTech Connect

    Miller, R.E.; Smith, D.L.

    1997-07-01

    This report documents a survey of the literature, and provides a compilation of data contained therein, for the {sup 32}S(p, {gamma}){sup 33}Cl reaction. Considerable attention is paid to properties of the levels in {sup 33}Cl which are located in the vicinity of excitation of the compound-nuclear system {sup 32}s + p near the proton separation energy for {sup 33}Cl. It is this particular energy region which is especially important for applications in nuclear astrophysics. Summaries of all the located references are provided and numerical data contained in them are compiled in EXFOR format where applicable.

  19. Examination of the different roles of neutron transfer in the sub-barrier fusion reactions 32S+Zr,9694 and 40Ca +Zr,9694

    NASA Astrophysics Data System (ADS)

    Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Scheid, W.; Zhang, H. Q.

    2015-01-01

    The sub-barrier capture (fusion) reactions 32S+90,94,96Zr, 36S+Zr,9690 , 40Ca +90,94,96Zr, and 48Ca +Zr,9690 with positive and negative Q values for neutron transfer are studied with the quantum diffusion approach and the universal fusion function representation. For these systems, the s -wave capture probabilities are extracted from the experimental excitation functions and are also analyzed. Different effects of the positive Qx n-value neutron transfer in the fusion enhancement are revealed in the relatively close reactions 32S+Zr,9694 and 40Ca +Zr,9694 .

  20. Selective population of states in fission fragments from the [sup 32]S+[sup 24]Mg reaction

    SciTech Connect

    Sanders, S.J.; Hasan, A.; Prosser, F.W. ); Back, B.B.; Betts, R.R.; Carpenter, M.P.; Henderson, D.J.; Janssens, R.V.F.; Khoo, T.L.; Moore, E.F.; Wilt, P.R.; Wolfs, F.L.H.; Wuosmaa, A.H. ); Beard, K.B. ); Benet, P. )

    1994-02-01

    The symmetric and near-symmetric mass fission yields from the [sup 32]S+[sup 24]Mg reaction have been studied in a particle-particle-[gamma] coincidence measurement. Evidence is presented for a selective population of states in [sup 28]Si fragments arising from the symmetric fission of the [sup 56]Ni compound nucleus. A statistical-model calculation of the expected strength to specific mutual excitations of the fission fragments is presented and compared to the experimental results. This calculation is found to describe the structures observed at high excitation energy in the fission [ital Q]-value spectra quite well. Analysis of the [gamma]-ray spectra indicates, however, that a specific set of states in [sup 28]Si, corresponding to a highly deformed prolate band, is populated more strongly than expected based on a purely spin-weighted, statistical decay of the compound nucleus. It is suggested that the population pattern of states in the fission fragments may reflect nuclear structure effects at the point of scission.

  1. Study of the high resolution spectrum of 32S16O18O: The ν1 and ν3 bands

    NASA Astrophysics Data System (ADS)

    Ulenikov, O. N.; Bekhtereva, E. S.; Krivchikova, Yu. V.; Zamotaeva, V. A.; Buttersack, T.; Sydow, C.; Bauerecker, S.

    2016-01-01

    The high resolution infrared spectrum of the 32S16O18O molecule was recorded for the first time with a Bruker IFS 120 HR Fourier transform interferometer in the region of 930-1580 cm-1 where the bands ν1 and ν3 are located. More than 3000 and about 2400 transitions were assigned in the experimental spectrum with the maximum values of quantum numbers Jmax. /Kamax. equal to 58/23 and 68/23 to the bands ν1 and ν3, respectively. The further weighted fit of experimentally assigned transitions was made with the Hamiltonian model which takes into account Coriolis resonance interaction between the vibrational states (100) and (001). The 81 microwave transitions of the states (100) and (001) known from the literature also were taken into account. As the result, a set of 26 fitted parameters was obtained which reproduces the experiment-based 2690 ro-vibrational energy values of the two bands with the drms = 1.8 ×10-4 cm-1. Microwave transitions are also reproduced with the accuracy close to experimental uncertainty.

  2. {sup 33}S hyperfine interactions in H{sub 2}S and SO{sub 2} and revision of the sulfur nuclear magnetic shielding scale

    SciTech Connect

    Helgaker, Trygve; Gauss, Jürgen; Cazzoli, Gabriele Puzzarini, Cristina

    2013-12-28

    Using the Lamb-dip technique, the hyperfine structure in the rotational spectra of H{sub 2}{sup 33}S and {sup 33}SO{sub 2} has been resolved and the corresponding parameters—that is, the sulfur quadrupole-coupling and spin–rotation tensors—were determined. The experimental parameters are in good agreement with results from high-level coupled-cluster calculations, provided that up to quadruple excitations are considered in the cluster operator, sufficiently large basis sets are used, and vibrational corrections are accounted for. The {sup 33}S spin-rotation tensor for H{sub 2}S has been used to establish a new sulfur nuclear magnetic shielding scale, combining the paramagnetic part of the shielding as obtained from the spin–rotation tensor with a calculated value for the diamagnetic part as well as computed vibrational and temperature corrections. The value of 716(5) ppm obtained in this way for the sulfur shielding of H{sub 2}S is in good agreement with results from high-accuracy quantum-chemical calculations but leads to a shielding scale that is about 28 ppm lower than the one suggested previously in the literature, based on the {sup 33}S spin-rotation constant of OCS.

  3. Differentiating atmospheric and mineral sources of sulfur during snowmelt using δ 34S, 35S activity, and δ 18O of sulfate and water as tracers

    NASA Astrophysics Data System (ADS)

    Shanley, J. B.; Mayer, B.; Mitchell, M. J.; Michel, R. L.; Bailey, S.; Kendall, C.

    2003-12-01

    The biogeochemical cycling of sulfur was studied during the 2000 snowmelt at Sleepers River Research Watershed in northeastern Vermont, USA using a combination of isotopic, chemical, and hydrometric measurements. The snowpack and 10 streams of varying size and land use were sampled for sulfate concentrations and isotopic analyses of 35S, δ 34S, and δ 18O of sulfate. Values of δ 18O of water were measured at one of the streams. Apportionment of atmospheric and mineral S sources based on δ 34S was possible at 7 of the 10 streams. Weathering of S-containing minerals was a major contributor to sulfate flux in streamwater, but atmospheric contributions exceeded 50% in several of the streams at peak snowmelt and averaged 41% overall. In contrast, δ 18Osulfate values of streamwater remained significantly lower than those of atmospheric sulfate throughout the melt period, indicating that atmospheric sulfate undergoes microbial redox reactions in the soil that replace the oxygen of atmospheric sulfate with isotopically lighter oxygen from soil water. Streamwater 35S activities were low relative to those of the snowpack; the youngest 35S-ages of the atmospheric S component in each of the 7 streams ranged from 184 to 320 days. Atmospheric S contributions to streamwater, as determined by δ 34S values, co-varied both with 35S activity and new water contributions as determined by δ 18Owater. However, the δ 18Osulfate and 35S ages clearly show that this new water carries very little of the atmospheric sulfate entering with the current snowmelt to the stream. Most incoming atmospheric sulfate first cycles through the organic soil S pool and ultimately reaches the stream as pedogenic sulfate.

  4. Kinetic Enrichment of 34S during Proteobacterial Thiosulfate Oxidation and the Conserved Role of SoxB in S-S Bond Breaking

    PubMed Central

    Alam, Masrure; Pyne, Prosenjit; Mazumdar, Aninda; Peketi, Aditya

    2013-01-01

    During chemolithoautotrophic thiosulfate oxidation, the phylogenetically diverged proteobacteria Paracoccus pantotrophus, Tetrathiobacter kashmirensis, and Thiomicrospira crunogena rendered steady enrichment of 34S in the end product sulfate, with overall fractionation ranging between −4.6‰ and +5.8‰. The fractionation kinetics of T. crunogena was essentially similar to that of P. pantotrophus, albeit the former had a slightly higher magnitude and rate of 34S enrichment. In the case of T. kashmirensis, the only significant departure of its fractionation curve from that of P. pantotrophus was observed during the first 36 h of thiosulfate-dependent growth, in the course of which tetrathionate intermediate formation is completed and sulfate production starts. The almost-identical 34S enrichment rates observed during the peak sulfate-producing stage of all three processes indicated the potential involvement of identical S-S bond-breaking enzymes. Concurrent proteomic analyses detected the hydrolase SoxB (which is known to cleave terminal sulfone groups from SoxYZ-bound cysteine S-thiosulfonates, as well as cysteine S-sulfonates, in P. pantotrophus) in the actively sulfate-producing cells of all three species. The inducible expression of soxB during tetrathionate oxidation, as well as the second leg of thiosulfate oxidation, by T. kashmirensis is significant because the current Sox pathway does not accommodate tetrathionate as one of its substrates. Notably, however, no other Sox protein except SoxB could be detected upon matrix-assisted laser desorption ionization mass spectrometry analysis of all such T. kashmirensis proteins as appeared to be thiosulfate inducible in 2-dimensional gel electrophoresis. Instead, several other redox proteins were found to be at least 2-fold overexpressed during thiosulfate- or tetrathionate-dependent growth, thereby indicating that there is more to tetrathionate oxidation than SoxB alone. PMID:23686269

  5. Organic Matter Sulfurization in the Cariaco Water Column Revealed by High-Sensitivity and Compound-Specific d34S Analyses.

    NASA Astrophysics Data System (ADS)

    Raven, M. R.; Sessions, A. L.; Adkins, J. F.; Thunell, R.

    2015-12-01

    Organic matter burial in marine sediments is a major process in the global carbon cycle, and enhanced organic matter burial is often associated with periods of global climatic and ecological change. Still, we have only a limited understanding of the processes that drive enhanced OM burial during oxygen-deficient conditions. Abiotic OM sulfurization has the potential to enhance the preservation of OM, but for this process to be significant it must compete with heterotrophic remineralization, most of which occurs before sinking particles reach the sea floor. We investigate the sources of sulfur to sinking particles in a modern marine basin using samples from the CARIACO fixed sediment trap time-series, applying recently developed methods for d34S analysis of small (≥20 nmol) sulfur pools and individual volatile organosulfur compounds. Relative to expectations for planktonic biomass, we find that sinking particles are both sulfur-rich and 34S-depleted. Higher apparent fluxes of 34S-depleted organic sulfur are associated with high OM export from the surface ocean, low terrestrial inputs, and high concentrations of both elemental S and the dominant non-polar organosulfur compound, C20 thiophene. We conclude that OM sulfurization is occurring in particles sinking through the Cariaco water column on timescales of days or less. Depending on the frequency of high OM export events, we estimate that this rapid sulfurization delivers roughly half of the total organic S present at 5 cm depth in underlying sediments. Accordingly, many OM-rich deposits in the geologic record may represent the products of water column sulfurization. This process provides a strong mechanistic feedback between oxygen deficiency and OM preservation.

  6. A compilation of information on the {sup 31}P(p,{alpha}){sup 28}Si reaction and properties of excited levels in the compound nucleus {sup 32}S

    SciTech Connect

    Miller, R.E.; Smith, D.L.

    1997-11-01

    This report documents a survey of the literature, and provides a compilation of data contained therein, for the {sup 31}P(p,{alpha}){sup 28}Si reaction. Attention is paid here to resonance states in the compound-nuclear system {sup 32}S formed by {sup 31}P + p, with emphasis on the alpha-particle decay channels, {sup 28}Si + {alpha} which populate specific levels in {sup 28}Si. The energy region near the proton separation energy for {sup 32}S is especially important in this context for applications in nuclear astrophysics. Properties of the excited states in {sup 28}Si are also considered. Summaries of all the located references are provided and numerical data contained in them are compiled in EXFOR format where applicable.

  7. Sub-barrier one- and two-neutron pickup measurements in {sup 32}S+{sup 93}Nb, {sup 98,100}Mo reactions at 180{degrees}

    SciTech Connect

    Roberts, R.B.; Gazes, S.B.; Mason, J.E.

    1993-04-01

    Excitation functions for sub-barrier one- and two-neutron pickup reactions were measured for E{sub lab}{le}106 MeV in {sup 32}S+{sup 93}Nb, {sup 98,100}Mo systems by detecting target-like recoils at 0{degrees} using a recoil mass spectrometer. Measured differential cross sections are compared to those predicted by the DWBA code PTOLEMY. The slopes of transfer probability versus distance of closest approach, are in good agreement with the slopes obtained from binding energies, indicating the absence of a {open_quotes}slope anomaly.{close_quotes} Angle-integrated transfer cross sections derived from measured 180{degrees} yields correlate with fusion enhancements in previously measured fusion yields for the {sup 32}S+{sup 98,100}Mo systems.

  8. Role of Barrier Modification and Inelastic Surface Excitations in Sub-Barrier Fusion of 16 32 S + 40 94 Zr Reaction

    NASA Astrophysics Data System (ADS)

    Gautam, Manjeet Singh; Rajni; Sharma, Manoj K.

    2016-04-01

    The fusion dynamics of 16 32 S + 40 94 Zr reaction at near and sub-barrier energies is investigated within the context of different theoretical approaches. The various theoretical models like one-dimensional Wong formula, ℓ-summed extended Wong formula, the energy-dependent Woods-Saxon potential model (EDWSP model), and coupled channel formulation have been used to address the impacts of nuclear structure degrees of freedom of the colliding pairs. The roles of different Skyrme forces along with Wong formalism are also tested in the analysis of the sub-barrier fusion dynamics of the 16 32 S + 40 94 Zr reaction. The influence of the low-lying surface vibrational states of the collision partners is investigated within the framework of coupled channel calculations performed by the code CCFULL. In the present work, it has been observed that the EDWSP model introduces barrier modification effects somewhat similar to those of the coupled channel approach, as well as those of using different Skyrme forces and hence it reasonably addresses the observed fusion data of 16 32 S + 40 94 Zr reaction in the close vicinity of the Coulomb barrier.

  9. The kinetics of catalytic incineration of (CH3)2S2 over the CuO-MoO3/gamma-Al2O3 catalyst.

    PubMed

    Wang, Ching-Huei; Lin, Shiow-Shyung; Weng, Hung-Shan

    2002-10-01

    In this study, by varying reaction conditions including particle size, space velocity, reactant concentration and reaction temperature, the kinetics of catalytic incineration of (CH3)2S2 catalyzed by the CuO-MoO3/gamma-Al2O3 catalyst was investigated. Three kinetic models, i.e., the power-rate law model, Langmuir-Hinshelwood model and Mars-Van Krevelen model, were applied to best fit the experimental results. It was shown that the Mars-Van Krevelen model was more appropriate than the other two models for describing the mechanism of catalytic incineration of (CH3)2S2 on the CuO-MoO3/gamma-Al2O3 catalyst. The reaction expression of the Mars-Van Krevelen model was as follows: -r=k(R)k(O)C(R)C(O) divided by alpha(k)(R)C(R) + k(O)C(O) where alpha is 5.5 and C(R) and C(O) represent concentrations of (CH3)2S2 and O2, respectively. The enlarged difference between experimental and predicted data was observed at higher operating temperatures. This might be due to the dominating mechanism at this temperature region was different. PMID:12403014

  10. Theoretical study of fusion reactions 32S + 94,96Zr and 40Ca + 94,96Zr and quadrupole deformation of 94Zr

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Zhao, WeiJuan; Zhao, EnGuang; Zhou, ShanGui

    2016-04-01

    The dynamic coupling effects on fusion cross sections for reactions 32S + 94,96Zr and 40Ca + 94,96Zr are studied with the universal fusion function formalism and an empirical coupled channel (ECC) model. An examination of the reduced fusion functions shows that the total effect of couplings to inelastic excitations and neutron transfer channels on fusion in 32S + 94Zr (40Ca + 94Zr) is almost the same as that in 32S + 96Zr (40Ca + 96Zr). The enhancements of the fusion cross section at sub-barrier energies due to inelastic channel coupling and neutron transfer channel coupling are evaluated separately by using the ECC model. The results show that effect of couplings to inelastic excitations channels in the reactions with 94Zr as target should be similar as that in the reactions with 96Zr as target. This implies that the quadrupole deformation parameters β 2 of 94Zr and 96Zr should be similar to each other. However, β 2's predicted from the finite-range droplet model, which are used in the ECC model, are quite different. Experiments on 48Ca + 94Zr or 36S + 94Zr are suggested to solve the puzzling issue concerning β 2 for 94Zr.

  11. Extreme 34S depletions in ZnS at the Mike gold deposit, Carlin Trend, Nevada: Evidence for bacteriogenic supergene sphalerite

    NASA Astrophysics Data System (ADS)

    Bawden, Thomas M.; Einaudi, Marco T.; Bostick, Benjamin C.; Meibom, Anders; Wooden, Joseph; Norby, John W.; Orobona, Michael J. T.; Page Chamberlain, C.

    2003-10-01

    We identified submicrometer-sized framboidal sphalerite (ZnS) below the base of supergene oxidation in a Carlin-type gold deposit of Eocene age in Nevada, United States, where the framboidal sphalerite forms a blanket-like body containing >400,000 metric tons of zinc. Framboidal sphalerite <0.1 μm in diameter, formed in the early Miocene, ranges from <0.1 to 0.35 mol% FeS; the δ34S values range from -25‰ to -70‰, the lowest values measured in a marine or terrestrial environment. These S isotope data demonstrate the involvement of sulfate-reducing bacteria and provide the first documentation that sphalerite can form significant supergene sulfide-enrichment blankets.

  12. Extreme 34S depletions in ZnS at the Mike gold deposit, Carlin Trend, Nevada: Evidence for bacteriogenic supergene sphalerite

    USGS Publications Warehouse

    Bawden, T.M.; Einaudi, M.T.; Bostick, B.C.; Meibom, A.; Wooden, J.; Norby, J.W.; Orobona, M.J.T.; Chamberlain, C.P.

    2003-01-01

    We identified submicrometer-sized framboidal sphalerite (ZnS) below the base of supergene oxidation in a Carlin-type gold deposit of Eocene age in Nevada, United States, where the framboidal sphalerite forms a blanket-like body containing >400,000 metric tons of zinc. Framboidal sphalerite <0.1 ??m in diameter, formed in the early Miocene, ranges from <0.1 to 0.35 mol% FeS; the ??34S values range from -25??? to -70???, the lowest values measured in a marine or terrestrial environment. These S isotope data demonstrate the involvement of sulfate-reducing bacteria and provide the first documentation that sphalerite can form significant supergene sulfide-enrichment blankets.

  13. Calculation of pre-equilibrium effects in neutron-induced cross section on 32,34S isotopes using the EMPIRE 3.2 code

    NASA Astrophysics Data System (ADS)

    Yettou, Leila; Belgaid, Mohamed

    2015-07-01

    In this study, a new version EMPIRE 3.2 code was used in the cross section calculations of (n,p) reactions and in the calculation of proton emission spectra produced by (n,xp) reactions. Exciton model predictions combined with the Kalbach angular distribution systematics were used and some parameters such as those of mean free path, cluster emission in terms of Iwamoto-Harada model, optical model potentials of Morillon for neutrons and protons in the energy range up to 20 MeV, level density for spherical nuclei of Gilbert-Cameron model and width fluctuation correction in terms of compound nucleus have been investigated our calculations. The excitation functions and the proton emission spectra for 32,34S nuclei were calculated, discussed and found in good agreement with available experimental data.

  14. Neutron multiplicities and energy sharing in the inelastic collisions of [sup 32]S on [sup 64]Ni at [ital E]/[ital A]=4. 9 MeV

    SciTech Connect

    Fiore, L.; D'Erasmo, G.; Fiore, E.M.; Pantaleo, A.; Paticchio, V.; Petruzzelli, F.; Quirini, A.; Tagliente, G.; Lanzano, G.; Pagano, A. Dipartimento di Fisica dell'Universita 70126 Bari Istituto Nazionale di Fisica Nucleare, Sezione di Catania )

    1994-09-01

    The neutron emission from the targetlike fragments (TLF) of the inelastic reactions of 157 MeV [sup 32]S on [sup 64]Ni has been measured. Neutron energy spectra and multiplicities have been extracted as a function of the dissipated energy for six targetlike fragments mass gates between [ital A]=56 and [ital A]=70. The comparison between the data and the results of a Monte Carlo simulation based on statistical model calculations with different assumptions on the excitation energy sharing between the reaction partners evidences a dependence from the net mass flow of the evolution of the excitation energy ratios with the energy loss.

  15. Angular correlations between heavy and light fragments in the reaction sup 32 S+ sup 26 Mg at E sub lab =163. 5 MeV

    SciTech Connect

    Cavallaro, S. ); Prete, G. ); Viesti, G. )

    1990-04-01

    Angular correlation measurements between heavy residues ({ital Z}{sub {ital R}}=23--13) and light fragments ({ital Z}{sub {ital L}}=2--10) have been performed for the reaction {sup 32}S+{sup 26}Mg at {ital E}{sub lab}=163.5 MeV. The binary nature of the mechanisms competing with fusion-evaporation is evidenced. Linear momentum analysis and velocity plots indicate contributions of binary reactions also for those elements that are generally believed to be produced by fusion-evaporation mechanisms.

  16. VizieR Online Data Catalog: ExoMol line lists for CS isotopologues (Paulose+, 2015)

    NASA Astrophysics Data System (ADS)

    Paulose, G.; Barton, E. J.; Yurchenko, S. N.; Tennyson, J.

    2015-07-01

    The files comprising this line list are in the standard ExoMol format, and are named XXcYYsst.dat, XXcYYstr.dat, where XX and YY are the mass numbers of the Carbon and Sulphur isotopes, respectively. The isotopologues covered including their nuclear spin degeneracy factors g_ns are: (12C)(32S) g_ns = 1 (12C)(33S) g_ns = 4 (12C)(34S) g_ns = 1 (12C)(36S) g_ns = 1 (13C)(32S) g_ns = 2 (13C)(33S) g_ns = 8 (13C)(34S) g_ns = 2 (13C)(36S) g_ns = 2 The partition functions from 1-3000K in 1K intervals for these isotopologues of CS are also provided in files named XXcYYspf.dat. (24 data files).

  17. Tetra­amminelithium triamminelithium tris­ulfide, [Li(NH3)4][Li(NH3)3S3

    PubMed Central

    Guentner, Christian; Korber, Nikolaus

    2012-01-01

    The title compound, [Li(NH3)4]+[Li(NH3)3S3]−, an ammo­niate of the previously unknown lithium tris­ulfide, was obtained from the reaction of lithium and sulfur in liquid ammonia. The asymmetric unit consists of two crystallographically independent formula units. The [Li(NH3)4]+ cations are close to regular LiN4 tetra­hedra. The anions contain LiSN3 tetra­hedra; the S—S—S bond angles are 110.43 (5) and 109.53 (5)°. In the crystal, the components are linked by multiple N—H⋯S hydrogen bonds. A weak N—H⋯N hydrogen bond is also present. PMID:23284314

  18. Tetra-amminelithium triamminelithium tris-ulfide, [Li(NH(3))(4)][Li(NH(3))(3)S(3)].

    PubMed

    Guentner, Christian; Korber, Nikolaus

    2012-11-01

    The title compound, [Li(NH(3))(4)](+)[Li(NH(3))(3)S(3)](-), an ammo-niate of the previously unknown lithium tris-ulfide, was obtained from the reaction of lithium and sulfur in liquid ammonia. The asymmetric unit consists of two crystallographically independent formula units. The [Li(NH(3))(4)](+) cations are close to regular LiN(4) tetra-hedra. The anions contain LiSN(3) tetra-hedra; the S-S-S bond angles are 110.43 (5) and 109.53 (5)°. In the crystal, the components are linked by multiple N-H⋯S hydrogen bonds. A weak N-H⋯N hydrogen bond is also present. PMID:23284314

  19. Isotopic variation ( δ15N, δ13C, and δ34S) with body size in post-larval estuarine consumers

    NASA Astrophysics Data System (ADS)

    Marie Wilson, Rachel; Chanton, Jeffrey; Lewis, Graham; Nowacek, Douglas

    2009-07-01

    Stable isotope analyses were conducted on fish and crabs in Apalachicola Bay, Florida (USA) to determine whether δ15N values are correlated with length within these species. Our objective was to define the smallest trophic unit of the system as a prelude to further isotopic evaluations of consumer trophic level in Apalachicola Bay. In some cases, the smallest trophic unit is the individual species; however, previous gut content analysis on organisms in this system indicated that subdivision by size class within species might be required. However, over the size ranges observed, there was no systematic change in the δ15N values of individual consumers. Analysis of the δ13C and δ34S values of these species reveal no obvious shifts in the utilization of organic matter sources with length that could be obscuring a trend in the δ15N signal. We find no isotopic evidence for a systematic trophic level increase within the species examined over the size ranges observed in this estuary. These results indicate that species rather than size class is the best predictor of trophic habit among these Apalachicola Bay consumers.

  20. Chemical weathering and the role of sulfuric and nitric acids in carbonate weathering: Isotopes (13C, 15N, 34S, and 18O) and chemical constraints

    NASA Astrophysics Data System (ADS)

    Li, Cai; Ji, Hongbing

    2016-05-01

    Multiple isotopes (13C-DIC, 34S and 18O-SO42-, 15N and 18O-NO3-) and water chemistry were used to evaluate weathering rates and associated CO2 consumption by carbonic acid and strong acids (H2SO4 and HNO3) in a typical karst watershed (Wujiang River, Southwest China). The dual sulfate isotopes indicate that sulfate is mainly derived from sulfide oxidation in coal stratum and sulfide-containing minerals, and dual nitrate isotopes indicate that nitrate is mainly derived from soil N and nitrification. The correlation between isotopic compositions and water chemistry suggests that sulfuric and nitric acids, in addition to carbonic acid, are involved in carbonate weathering. The silicate and carbonate weathering rates are 7.2 t km-2 yr-1 and 76 t km-2 yr-1, respectively. In comparison with carbonate weathering rates (43 t km-2 yr-1) by carbonic acid alone, the subsequent increase in rates indicates significant enhancement of weathering when combined with sulfuric and nitric acids. Therefore, the role of sulfuric and nitric acids in the rock weathering should be considered in the global carbon cycle.

  1. The effect of acid rain and altitude on concentration, δ34S, and δ18O of sulfate in the water from Sudety Mountains, Poland

    USGS Publications Warehouse

    Szynkiewicz, Anna; Modelska, Magdalena; Jedrysek, Mariusz Orion; Mastalerz, Maria

    2008-01-01

    Sulfate content, δ34S(SO42−), δ18O(SO42−), and δ18O(H2O) values revealed a remarkable dependence on the altitude. The calculated altitude effects for five season averages of these parameters were − 1.00 mg/l/100 m, − 0.18‰/100 m, − 0.27‰/100 m, and − 0.17‰/100 m, respectively. This dependence on the altitude resulted mainly from the mixing of sulfates of different origins such as anthropogenic sulfate, sulfate produced in the soil within the weathered zone of the massif, and that one from the tree canopy. The oxygen isotope mass balance indicates that, in the study area, about one third of the sulfate delivered to the surface and groundwater by modern precipitation comes from anthropogenic pollution. Further interaction of meteoric water within the weathered rocks causes a continuous decrease of δ18O(SO42−) values resulting from biological transformation of the sulfate due to plant vegetation and decomposition of organic matter.

  2. Investigation of Shell Effects in the Fusion-Fission Process in the Reaction 34S + 186W Near the Interaction Barrier

    NASA Astrophysics Data System (ADS)

    Harca, I. M.; Kozulin, E. M.; Bogachev, A.; Dmitriev, S. N.; Itkis, J.; Knyazheva, G.; Loktev, T.; Novikov, K.; Vardaci, E.; Azaiez, F.; Gottardo, A.; Matea, I.; Verney, D.; Chubarian, G.; Hanappe, F.; Piot, J.; Schmitt, C.; Trzaska, W. H.

    2015-06-01

    The reaction 34S + 186W at Elab = 160 MeV was investigated with the aim of diving into the features of the fusion-fission process. Gamma rays coincident with binary reaction fragments were measured using the high efficiency gamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometer for fission fragments registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. Evidence of symmetric and asymmetric fission modes were observed in the mass and TKE distributions, occurring due to shell effects in the fragments. The coupling of the ORGAM and CORSET setups enables the FF-γ coincident measurement which offers the opportunity to extract the isotopic distribution of the fragments of different masses formed in the aforementioned reaction and to find the exact neutron multiplicity, the average spin and average angular momenta. Details regarding the experimental setup, methods of processing the acquisitioned data and preliminary results are presented.

  3. Tracking Natal Dispersal in a Coastal Population of a Migratory Songbird Using Feather Stable Isotope (δ2H, δ34S) Tracers

    PubMed Central

    Haché, Samuel; Hobson, Keith A.; Bayne, Erin M.; Van Wilgenburg, Steven L.; Villard, Marc-André

    2014-01-01

    Adult birds tend to show high fidelity to their breeding territory or disperse over relatively short distances. Gene flow among avian populations is thus expected to occur primarily through natal dispersal. Although natal dispersal is a critical demographic process reflecting the area over which population dynamics take place, low recapture rates of birds breeding for the first time have limited our ability to reliably estimate dispersal rates and distances. Stable isotope approaches can elucidate origins of unmarked birds and so we generated year- and age-specific δ2H and δ34S feather isoscapes (ca. 180 000 km2) of coastal-breeding Ovenbirds (Seiurus aurocapilla) and used bivariate probability density functions to assign the likely natal areas of 35 males recruited as first-year breeders into a population located in northwestern New Brunswick, Canada. Most individuals (80–94% depending on the magnitude of an age correction factor used; i.e. 28–33 out of 35) were classified as residents (i.e. fledged within our study area) and estimated minimum dispersal distances of immigrants were between 40 and 240 km. Even when considering maximum dispersal distances, the likely origin of most first-year breeders was<200 km from our study area. Our method identified recruitment into our population from large geographic areas with relatively few samples whereas previous mark-recapture based methods have required orders of magnitude more individuals to describe dispersal at such geographic scales. Natal dispersal movements revealed here suggest the spatial scale over which many population processes are taking place and we suggest that conservation plans aiming to maintain populations of Ovenbirds and ecologically-similar species should consider management units within 100 or at most 200 km of target breeding populations. PMID:24740314

  4. Stable Isotope (δ13C, δ15N, δ34S) Analysis and Satellite Telemetry Depict the Complexity of Gray Wolf (Canis lupus) Diets in Southwest Alaska

    NASA Astrophysics Data System (ADS)

    Stanek, A.; Watts, D. E.; Cohn, B. R.; Spencer, P.; Mangipane, B.; Welker, J. M.

    2010-12-01

    Throughout Alaska, gray wolves (Canis lupus) are a top predator of large ungulates. While they primarily rely on ungulates such as moose (Alces alces) and caribou (Rangifer tarandus) as food, they are opportunistic and use alternative resources. The variation and supplemental protein sources in wolf diet has not been studied extensively on live animals currently using the landscape. With large seasonal influxes of Pacific salmon (Oncorhynchus sp.) into Alaska, terrestrial carnivore use of marine species is of particular interest. Using stable isotope (δ13C, δ15N, δ34S) analysis of wolf guard hair and blood, this study aims to determine the proportion of marine derived nutrients (MDN) in the diet of wolf packs within and surrounding Lake Clark National Park and Preserve and Alaska Peninsula and Becharof National Wildlife Refuges in Southwest Alaska. Satellite telemetry from the animals sampled facilitates quantification of landscape use patterns in correspondence with isotopic traits. Wolf pack territories within and surrounding the Lake Clark region appear to vary in spatial extent and in availability of MDN, such as salmon. Initial analysis shows that two packs with smaller home ranges, centrally located around areas with greater salmon availability, have enriched δ15N values compared to packs that have larger home ranges not centralized around salmon spawning waters. This pattern of isotopic enrichment is found in red blood cells, blood serum and hair, representing diets over different time scales. The enrichment in both blood and hair indicates a sustained use of MDN over the previous six to nine months. In the Lake Clark region, simple mixing model estimates suggest that up to 30% of wolf pack diets may be from marine sources. In contrast, packs with larger home ranges and less access to salmon have stable isotope values representative of a terrestrial diet.

  5. Nuclear orientation in the reaction {sup 34}S+{sup 238}U and synthesis of the new isotope {sup 268}Hs

    SciTech Connect

    Nishio, K.; Ikezoe, H.; Mitsuoka, S.; Nagame, Y.; Nishinaka, I.; Hofmann, S.; Hessberger, F. P.; Ackermann, D.; Duellmann, Ch. E.; Heinz, S.; Heredia, J. A.; Khuyagbaatar, J.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R.; Schaedel, M.; Antalic, S.; Saro, S.; Aritomo, Y.

    2010-08-15

    The synthesis of isotopes of the element hassium was studied using the reaction {sup 34}S+{sup 238}U{yields}{sup 272}Hs{sup *}. At a kinetic energy of 163.0 MeV in the center-of-mass system we observed one {alpha}-decay chain starting at the isotope {sup 267}Hs. The cross section was 1.8{sub -1.5}{sup +4.2} pb. At 152.0 MeV one decay of the new isotope {sup 268}Hs was observed. It decays with a half-life of 0.38{sub -0.17}{sup +1.8} s by 9479{+-}16 keV {alpha}-particle emission. Spontaneous fission of the daughter nucleus {sup 264}Sg was confirmed. The measured cross section was 0.54{sub -0.45}{sup +1.3} pb. In-beam measurements of fission-fragment mass distributions were performed to obtain information on the fusion probability at various orientations of the deformed target nucleus. The distributions changed from symmetry to asymmetry when the beam energy was changed from above-barrier to sub-barrier values, indicating orientation effects on fusion and/or quasifission. It was found that the distribution of symmetric mass fragments originates not only from fusion-fission, but has a strong component from quasifission. The result was supported by a calculation based on a dynamical description using the Langevin equation, in which the mass distributions for fusion-fission and quasifission fragments were separately determined.

  6. Rare earth element and stable sulphur (δ 34S) isotope study of baryte-copper mineralization in Gulani area, Upper Benue Trough, NE Nigeria

    NASA Astrophysics Data System (ADS)

    El-Nafaty, Jalo Muhammad

    2015-06-01

    The geology of Gulani area comprises of inliers of diorite and granites of the Older Granite suite of the Pan-African (600 ± 150 Ma) age within Cretaceous sediments of the Bima, Yolde and Pindiga Formations and the Tertiary/Quaternary basalts of the Biu Plateau. Epigenetic baryte-copper mineralization occurs as baryte veins within the Bima and Yolde sandstones and fracture-filling malachite in Pan-African granites. Unaltered (distal), hydrothermally altered (proximal) granites and sandstones and vein materials (mineral separates of baryte and chalcopyrite/malachite mineralized rocks) were analysed for rare earth elements (REE) and stable sulphur isotopes. The REE patterns of the unaltered rocks (both granites and sandstones) indicate background values before mineralization, depicted by enriched LREE, depleted HREE and weak negative Eu anomalies typical of Pan-African (calc-alkaline) granites and sandstones derived from them. On the other hand, the hydrothermally altered and mineralized rocks and mineral separates show a distinct baryte and copper mineralization sub-systems characterized by similar high LREE and corresponding low HREE abundances. However, the negative Eu anomalies of the copper sub-system hosted by granites are typical of Pan-African (calc-alkaline) granites. The sandstone host rocks of the baryte sub-system are marked by positive Eu anomalies interpreted as reflecting the injection and subsequent deposition of the baryte-bearing hydrothermal solutions under oxidizing conditions. The baryte mineral separates show δ (34S) isotope range of 12.3-13.1‰ (CDT) indicating sulphur from sedimentary formation sources. This ruled out magmatic source of the sulphur from the nearby Tertiary/Quaternary volcanic rocks of the Biu Plateau as well as ocean water. However, the stable sulphur isotopic determination of the sulphides (chalcopyrite/malachite mineral separates and mineralized rocks) did not yield peaks and therefore no inferences drawn in this regard.

  7. K-shell ionization by /sup 16/O and /sup 32/S ions: Reduced-velocity dependence of the binding effect

    SciTech Connect

    Seidel, J.; Roehl, S.; Lorek, R.; Huchler, S.; Dost, A.M.

    1985-10-01

    K-shell ionization probabilities P/sub K/ were measured for 2.2-MeV/u /sup 16/O ions with impact parameter b = 16--51 fm on 24 targets ranging from Sc to Bi. For Bi, the distribution P/sub K/(b) was also measured. Total K-shell ionization cross sections sigma/sub K/ for /sup 16/O and /sup 32/S projectiles are reported for the same target range. Semiclassical calculations using the velocity-dependent electron binding energies from the relativistic two-center approximation of Andersen, Laegsgaard, and Lund reproduce both P/sub K/ and sigma/sub K/ very well, except where polarization effects become important.

  8. Fusion and binary reactions in the collision of /sup 32/S on /sup 26/Mg at /ital E//sub lab/=163. 5 MeV

    SciTech Connect

    Cavallaro, S.; Zhi, Y. S.; Prete, G.; Viesti, G.

    1989-07-01

    Measurements of heavy fragments produced in the interaction of /sup 32/S with /sup 26/Mg at /ital E//sub lab/=163.5 MeV have been performed to study the interplay of the fusion reaction and binary processes. Experimental angular distributions, velocity spectra, and angle-integrated cross sections of detected heavy fragments have been compared with predictions of statistical models. The comparison shows that complete fusion exhausts the production of residues in the range /ital Z/=26--22. For fragments with atomic number /ital Z/=21 and /ital Z/=20 some other mechanism is also present. The analysis of energy spectra, angular distributions, and total kinetic energy of projectile-like fragments (/ital Z/=19--6) shows that the main process to limit fusion is an inelastic mechanism with large energy damping.

  9. Fusion reactions between /sup 32/S and /sup 24,25,26/Mg in the energy region E/sub lab/ = 90--150 MeV

    SciTech Connect

    Cavallaro, S.; Xiao, L.Y.; Sperduto, M.L.

    1985-11-01

    Fusion excitation functions for /sup 32/S+ /sup 24,25,26/Mg in the incident energy region E/sub lab/ = 90 to 150 MeV were measured by means of the in-beam ..gamma..-spectroscopy method. In order to suppress background and take into account the contribution of unstable residual nuclei to the in-beam yields of the daughter residues, a computer-controlled chopper system was assembled on the beam line to measure the in-beam and off-beam spectra of the ..gamma.. rays. Detailed comparison was made between the present measurement and the available data obtained by other methods. The measured A and Z distribution was compared with statistical calculations. The fusion excitation functions, which exhibit a change of slope with respect to low energy data, showing evident limitation on the fusion in this energy region, were analyzed in terms of the interaction barrier model and the statistical yrast line model.

  10. Storing keV negative ions for an hour: the lifetime of the metastable ^(2)P((1/2)^(o)) level in ^(32)S^(-).

    PubMed

    Bäckström, E; Hanstorp, D; Hole, O M; Kaminska, M; Nascimento, R F; Blom, M; Björkhage, M; Källberg, A; Löfgren, P; Reinhed, P; Rosén, S; Simonsson, A; Thomas, R D; Mannervik, S; Schmidt, H T; Cederquist, H

    2015-04-10

    We use a novel electrostatic ion storage ring to measure the radiative lifetime of the upper level in the 3p^{5} ^{2}P_{1/2}^{o}→3p^{5} ^{2}P_{3/2}^{o} spontaneous radiative decay in ^{32}S^{-} to be 503±54  sec. This is by orders of magnitude the longest lifetime ever measured in a negatively charged ion. Cryogenic cooling of the storage ring gives a residual-gas pressure of a few times 10^{-14} mbar at 13 K and storage of 10 keV sulfur anions for more than an hour. Our experimental results differ by 1.3σ from the only available theoretical prediction [P. Andersson et al., Phys. Rev. A 73, 032705 (2006)]. PMID:25910117

  11. Fock-space multireference coupled-cluster calculations of the hyperfine structure of isoelectronic {sup 33}S{sup -} and {sup 35,37}Cl

    SciTech Connect

    Das, Madhulita; Chaudhuri, Rajat K.; Chattopadhyay, Sudip; Mahapatra, Uttam Sinha

    2011-10-15

    Due to its flexibility and possible systematic improvement, the Fock-space (FS) multireference coupled-cluster (MRCC) method remains a very important tool for the computation of energy differences of spectroscopic interest. In the present work, the FS MRCC method for the electron detachment process has been applied to determine the magnetic hyperfine constant A{sub J} and nuclear quadrupole moments Q (related to electric hyperfine constant B{sub J}) for the lowest multiplets of {sup 33}S{sup -}, {sup 35}Cl, and {sup 37}Cl with Dirac-Fock orbitals. In addition, we also report {sup 2}P{sub 3/2}([Ne]3s{sup 2}3p{sup 5}) {yields} {sup 2}P{sub 1/2}([Ne]3s{sup 2}3p{sup 5}) magnetic dipole transition matrix element and electron affinity of {sup 35}Cl (i.e., ionization energy of Cl{sup -}). Calculated properties are in very good agreement with the available new standard or reference values.

  12. Biogeochemical Indicators in High- and Low-Arctic Marine and Terrestrial Avian Community Changes: Comparative Isotopic (13C, 15N, and 34S) Studies in Alaska and Greenland

    NASA Astrophysics Data System (ADS)

    Causey, D.; Bargmann, N. A.; Burnham, K. K.; Burnham, J. L.; Padula, V. M.; Johnson, J. A.; Welker, J. M.

    2011-12-01

    Understanding the complex dynamics of environmental change in northern latitudes is of paramount importance today, given documented rapid shifts in sea ice, plant phenology, temperatures, deglaciation, and habitat fidelity. This knowledge is particularly critical for Arctic avian communities, which are integral components by which biological teleconnections are maintained between the mid and northern latitudes. Furthermore, Arctic birds are fundamental to Native subsistence lifestyles and a focus for conservation activities. Avian communities of marine and terrestrial Arctic environments represent a broad spectrum of trophic levels, from herbivores (eg., geese Chen spp.), planktivores (eg., auklets Aethia spp.), and insectivores (eg., passerines: Wheatears Oenanthe spp., Longspurs Calcarius spp.), to predators of marine invertebrates (eg., eiders Somateria spp.), nearshore and offshore fish (eg., cormorants Phalacrocorax spp, puffins Fratercula spp.), even other bird species (eg., gulls Larus spp., falcons Peregrinus spp.). This diversity of trophic interconnections is an integral factor in the dynamics of Arctic ecosystem ecology, and they are key indicators for the strength and trajectories of change. We are especially interested in their feeding ecology, using stable isotope-diet relations to examine historical diets and to predict future feeding ecology by this range of species. Since 2009, we have been studying the foodweb ecology using stable isotopes (δ13C, δ15N, δ34S) of contemporaneous coastal and marine bird communities in High Arctic (Northwest Greenland) and Low Arctic (western Aleutian Islands, AK). We are quantifying the isotopic values of blood, organ tissues, and feathers, and have carried out comparisons between native and lipid-extracted samples. Although geographically distant, these communities comprise similar taxonomic and ecological congeners, including several species common to both (eg., Common Eider, Black-legged Kittiwake, Northern

  13. Sulfur isotope homogeneity of lunar mare basalts

    NASA Astrophysics Data System (ADS)

    Wing, Boswell A.; Farquhar, James

    2015-12-01

    We present a new set of high precision measurements of relative 33S/32S, 34S/32S, and 36S/32S values in lunar mare basalts. The measurements are referenced to the Vienna-Canyon Diablo Troilite (V-CDT) scale, on which the international reference material, IAEA-S-1, is characterized by δ33S = -0.061‰, δ34S ≡ -0.3‰ and δ36S = -1.27‰. The present dataset confirms that lunar mare basalts are characterized by a remarkable degree of sulfur isotopic homogeneity, with most new and published SF6-based sulfur isotope measurements consistent with a single mass-dependent mean isotopic composition of δ34S = 0.58 ± 0.05‰, Δ33S = 0.008 ± 0.006‰, and Δ36S = 0.2 ± 0.2‰, relative to V-CDT, where the uncertainties are quoted as 99% confidence intervals on the mean. This homogeneity allows identification of a single sample (12022, 281) with an apparent 33S enrichment, possibly reflecting cosmic-ray-induced spallation reactions. It also reveals that some mare basalts have slightly lower δ34S values than the population mean, which is consistent with sulfur loss from a reduced basaltic melt prior to eruption at the lunar surface. Both the sulfur isotope homogeneity of the lunar mare basalts and the predicted sensitivity of sulfur isotopes to vaporization-driven fractionation suggest that less than ≈1-10% of lunar sulfur was lost after a potential moon-forming impact event.

  14. High-resolution quadruple sulfur isotope analyses of 3.2 Ga pyrite from the Barberton Greenstone Belt in South Africa reveal distinct environmental controls on sulfide isotopic arrays

    NASA Astrophysics Data System (ADS)

    Roerdink, Desiree L.; Mason, Paul R. D.; Whitehouse, Martin J.; Reimer, Thomas

    2013-09-01

    Multiple sulfur isotopes in Paleoarchean pyrite record valuable information on atmospheric processes and emerging microbial activity in the early sulfur cycle. Here, we report quadruple sulfur isotope data (32S, 33S, 34S, 36S) analyzed by secondary ion mass spectrometry from pyrite in a 3.26-3.23 Ga sedimentary barite deposit in the Barberton Greenstone Belt, South Africa. Our results demonstrate the presence of distinct pyrite populations and reproducible isotopic arrays in barite-free and barite-rich samples. The most 34S-depleted signatures with weakly positive Δ33S34S were found in disseminated pyrite in barite, whereas positive Δ33S-values with negative Δ33S34S and Δ36S/Δ33S = -0.9 ± 0.2 were exclusively observed in pyrite hosted by chert, dolomite, conglomerate and breccia. We interpret these variations to be related to local redox reactions and mixing in the sulfide phase, rather than representing primary atmospheric variability alone. The strong correlation between lithology and isotopic composition indicates distinct environments of sulfide formation linked to local sulfate concentrations and fluctuating inputs from different sulfur metabolisms. Strongly 34S-depleted sulfide was formed by microbial sulfate reduction at [SO42-] > 200 μM during deposition of barite-rich sediments, whereas isotope effects were suppressed when sulfate levels decreased during deposition of terrigeneous clastic rocks. Positive Δ33S-values indicate an increased input of sulfide derived from elemental sulfur metabolisms when sulfate concentrations fell below 200 μM. Our results support an important role for local sulfate concentrations on the expression of biogenic sulfur isotope signatures in some of the oldest rocks on Earth.

  15. Characterization of the nicotinic ligand 2-[18F]fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine in vivo.

    PubMed

    Valette, H; Bottlaender, M; Dollé, F; Guenther, I; Coulon, C; Hinnen, F; Fuseau, C; Ottaviani, M; Crouzel, C

    1999-01-01

    The biodistribution of the nicotinic acetylcholine receptor (nAChR) radioligand 2-[18F]fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine ([18F]fluoro-A-85380, half-life of fluorine-18 = 110 min) in selected rat brain areas was assessed in vivo. The radiotracer showed a good penetration in the brain. The regional distribution of the radioligand was consistent with the density of nAChRs determined from previous studies in vitro. Sixty minutes post-injection, the highest uptake was observed in the thalamus, (1% I.D./g tissue), an intermediate one in the frontal cortex (0.78% I.D./g tissue), and the lowest in the cerebellum (0.5% I.D./g tissue). Pretreatment with several nAChR ligands (nicotine, cytisine, epibatidine, unlabeled fluoro-A-85380) substantially reduced uptake of the radioligand in the three cerebral areas. Pretreatment with the nAChR channel blocker mecamylamine or with the muscarinic receptor antagonist dexetimide had no appreciable effect on the uptake of fluoro-A-85380. These results support the high in vivo selectivity and specificity of fluoro-A-85380. Therefore, [18F]fluoro-A-85380 may be useful for positron emission tomography study of nAChRs in humans. PMID:10072197

  16. N2 and O2 pressure broadening and pressure shift in the 4ν2 band of 16O12C32S

    NASA Astrophysics Data System (ADS)

    Galalou, S.; Ben Mabrouk, K.; Aroui, H.; Kwabia Tchana, F.; Willaert, F.; Flaud, J.-M.

    2011-12-01

    To measure accurately OCS concentrations in planetary atmospheres, it is important to know precisely nitrogen and oxygen pressure broadening and pressure-induced shift coefficients for the lines used in the retrievals. We present in this study the corresponding coefficients for lines of the P and R branches of the 4ν2 band of the primary isotopologue of carbonyl sulfide (16O12C32S).For this purpose, infrared absorption spectra of a natural carbonyl sulfide (OCS) gas sample were recorded at an unapodized resolution of 0.004 cm-1, at room temperature for different pressures of N2 and O2, using a Bruker IFS125HR spectrometer at the LISA Laboratory in France. The line parameters were derived using the multispectrum fitting method applied to the measured shapes of the lines, including the interference effects caused by the line overlaps.The results are compared with earlier measurements and with values calculated using a semi-classical model based upon the Robert and Bonamy formalism that reproduces rather well the experimental m (m=-J for P(J) lines and m=J+1 for R(J) lines) quantum number dependence of the N2 and O2 broadening coefficients. On the other hand most of the lines studied here have positive shift coefficients, which do not show any systematic dependence on m. However, in previous studies of the ν3, 2ν3 and ν2 bands, these coefficients were negative for all lines.

  17. Tracking atmospheric sulphur pollution from the study of Racomitrium lanuginosum mosses in Iceland: A multi-isotope approach (δ34S, 206Pb/204Pb, δ13C and δ15N)

    NASA Astrophysics Data System (ADS)

    Proust, E.; Widory, D.; Gautason, B.; Rogers, K.; Morrison, J.

    2010-12-01

    Among terrestrial plants, the applicability of mosses as monitoring organisms of atmospheric pollutants is a world-wide accepted technique due to their special biological and morphologic characteristics as nonvascular plants. They are commonly regarded as the best bioindicators of air quality because they can accumulate sulphur (S) and other elements to a far greater level than is necessary for their physiological needs. This study aims at using different isotope systematics δ34S, 206Pb/204Pb, δ13C and δ15N) to help understand the origin of S in the atmophsere of Reykjavik and its vicinity, and especially the potential contribution of surrounding geothermal plants. The selected Icelandic woolly fringe moss (Racomitrium lanuginosum (Hedw.) Brid.) is extremely common in lava fields and gravely and stony areas. Samples were taken in four distinct sampling sites around the city of Reykjavik: Bláfjöll area (south-eastern suburb of the city), and close to three power plants: Hellisheioarvirkjun (northern suburb of the city), Svartsengi (south-western suburb of the city) and Nesjavellir (north-eastern suburb of the city). Results show that, whatever the sampling context is, S is controlled by a binary mixing, between i) a high δ34S (around 16‰) end-member, characteristic of mosses from Hellisheioarvirkjun, and ii) a low δ34S (around -2‰) end-member, characteristic of mosses from Nesjavellir. The multi-isotope approach, confirms this binary relation and helps to constrain the different end-members involved.

  18. Application of 34S analysis for elucidating terrestrial, marine and freshwater ecosystems: Evidence of animal movement/husbandry practices in an early Viking community around Lake Mývatn, Iceland

    NASA Astrophysics Data System (ADS)

    Sayle, Kerry L.; Cook, Gordon T.; Ascough, Philippa L.; Hastie, Helen R.; Einarsson, Árni; McGovern, Thomas H.; Hicks, Megan T.; Edwald, Ágústa; Friðriksson, Adolf

    2013-11-01

    Carbon and nitrogen stable isotope ratios (δ13C and δ15N) have been used widely in archaeology to investigate palaeodiet. Sulphur stable isotope ratios (δ34S) have shown great promise in this regard but the potential of this technique within archaeological science has yet to be fully explored. Here we report δ34S, δ13C and δ15N values for 129 samples of animal bone collagen from Skútustaðir, an early Viking age (landnám) settlement in north-east Iceland. This dataset represents the most comprehensive study to date of its kind on archaeological material and the results show a clear offset in δ34S values between animals deriving their dietary resources from terrestrial (mean = +5.6 ± 2.8‰), freshwater (mean = -2.7 ± 1.4‰) or marine (mean = +15.9 ± 1.5‰) reservoirs (with the three food groups being significantly different at 2σ). This offset allows reconstruction of the dietary history of domesticated herbivores and demonstrates differences in husbandry practices and animal movement/trade, which would be otherwise impossible using only δ13C and δ15N values. For example, several terrestrial herbivores displayed enriched bone collagen δ34S values compared to the geology of the Lake Mývatn region, indicating they may have been affected by sea-spray whilst being pastured closer to the coast, before being traded inland. Additionally, the combination of heavy δ15N values coupled with light δ34S values within pig bone collagen suggests that these omnivores were consuming freshwater fish as a significant portion of their diet. Arctic foxes were also found to be consuming large quantities of freshwater resources and radiocarbon dating of both the pigs and foxes confirmed previous studies showing that a large freshwater radiocarbon (14C) reservoir effect exists within the lake. Overall, these stable isotope and 14C data have important implications for obtaining a fuller reconstruction of the diets of the early Viking settlers in Iceland, and may allow

  19. ABT-089 [2-methyl-3-(2-(S)-pyrrolidinylmethoxy)pyridine dihydrochloride]: II. A novel cholinergic channel modulator with effects on cognitive performance in rats and monkeys.

    PubMed

    Decker, M W; Bannon, A W; Curzon, P; Gunther, K L; Brioni, J D; Holladay, M W; Lin, N H; Li, Y; Daanen, J F; Buccafusco, J J; Prendergast, M A; Jackson, W J; Arneric, S P

    1997-10-01

    ABT-089 [2-methyl-3-(2-(S)-pyrrolidinylmethoxy)pyridine dihydrochloride], a novel ligand at neuronal nicotinic acetylcholine receptors with reduced adverse effects and improved oral bioavailability relative to (-)-nicotine, was tested in a variety of cognitive tests in rats and monkeys. Administered acutely, ABT-089 only marginally improved the spatial discrimination water maze performance of septal-lesioned rats. However, more robust improvement (45% error reduction on the last training day) was observed when ABT-089 was administered continuously via subcutaneous osmotic pumps (minimum effective dose: 1.3 micromol/kg/day). Continuous infusion of (-)-nicotine produced comparable improvement in the spatial discrimination water maze performance of septal-lesioned rats, but a 40-fold higher dose of (-)-nicotine was required (62 micromol/kg/day). Continuous infusion of ABT-089 to aged rats enhanced spatial learning in a standard Morris water maze, as indexed by spatial bias exhibited during a probe trial conducted after 4 days of training, but not when they were subsequently trained in a two-platform spatial discrimination water maze. The compound induced a small impairment in young rats on the standard water maze, but not on the two-platform task. A probe trial conducted after additional training in the standard water maze revealed no age or drug effects. ABT-089 did not affect performance of either the aged or young rats during inhibitory (passive) avoidance training. Also, continuous infusion of ABT-089 did not affect responses to acoustic startle or prepulse inhibition of acoustic startle in young, aged or septal-lesioned rats and did not affect locomotor activity in either sham-lesioned or septal-lesioned rats. In monkeys, acute administration of ABT-089 modestly improved the delayed matching-to-sample performance of mature, adult monkeys and more robustly improved performance in aged monkeys. Improved performance in the aged monkeys was restricted to the longest delay intervals and was not accompanied by changes in response latencies. PMID:9336330

  20. High Resolution Infrared Spectra of the v2, v3, v4 and 2v3 Bands of 32S16O3

    SciTech Connect

    Maki, Arthur G.; Blake, Thomas A.; Sams, Robert L.; Vulpanovici, Nicolae; Barber, Jeffrey B.; Chrysostom, Engelene; Masiello, Tony; Nibler, Joseph W.; Weber, Alfons

    2001-09-14

    New measurements are reported for the infrared spectrum of sulfur trioxide, 32S16O3, with resolutions ranging from 0.0015 cm-1 to 0.0025 cm-1. New rovibrational constants have been measured for the fundamentals v2, v3, and v4, and the overtone band 2v3. Comparisons are made with the earlier high resolution measurements on SO3 and the high correlation among some of the constants related to the Coriolis coupling of the v2 and v4 levels is duscussed in order to understand the areas of disagreement with the arlier work. Splittings of some of the levels are observed and hte splitting constant for K = 3 of the ground state is determined for the first time. Other observed splittings include the K = 1 levels of 2v3 (I = 2), the K = 2 levels of the v3 and v4 states and the K = 3 levels of v2. This analysis shows that there are level corssings between the I = 0 and I = 2 states of 2v3 that allow one to determine the separation of the sub-band centers for those two states even thoug the I = o state is a dark state. This is a generalized phenomenon that should be found for many other molecules with the same symmetry. The I-type resonance constant that couples the I = 0 and 2 states is roughly the same as q3 which causes the splitting of the I = 1 levels of the v3 fundamental.

  1. Triple isotope composition of CAS on the MC-ICPMS Neptune

    NASA Astrophysics Data System (ADS)

    Paris, G.; Adkins, J. F.; Sessions, A. L.; Fehrenbacher, J. S.; Spero, H. J.; Fischer, W. W.

    2012-12-01

    Exploring the isotopic composition of sulfur from Carbonate Associated Sulfates (CAS) during geological times provide essential information on the global sulfur cycle and redox budget at the surface of the Earth. For carbonates, existing methods combining extraction of sulfate by precipitation of BaSO4 and analyses by gas source mass spectrometry requires samples usually on the order of magnitude of a few to tens of gram. Recent use of the MC-ICPMS 'Neptune' demonstrated that the analysis of much smaller sulphide samples (Craddock et al., 2008) can still produce precise δ34S values. Thanks to the combination of a low detection limit and the extraction of sulfate by ion chromatography, we are able to work on carbonate samples three orders of magnitude smaller than typical CAS analyses. An Aridus is hooked to the Neptune as an introduction system to drastically decrease oxygen and hydride interferences on the sulfur peaks. Working in High Resolution (M/ΔM=10000), 32S-H interferences can be resolved and the 33S signal can be measured on an interference-free narrow shoulder. This method allows34S /32S and 33S/32S ratios with a 2σ reproducibility of 0.1-0.2 ‰ for δ34S and Δ33S values. This analytical breakthrough helps us to investigate a new category of samples. It becomes possible to work on sample as small as a few milligrams for modern carbonates or 40 mg for samples with sulfate concentrations of only 50 ppm. However, isotopic composition measurement on the Neptune requires the removal of the sample matrix so that samples are analyzed as sodium sulfate diluted in 5% HNO3. The purification of the sample is achieved through Ca++ removal using a micro-column of Dionex AG50X8 resin and then addition of sodium hydroxide. This method allows exchange of Ca++ (and other cations) for H+. Sulfate can then be concentrated by evaporation for analysis on the Neptune. We apply this method to the tests of Orbulina universa that were grown in artificial seawater of

  2. Multiple S-isotopic evidence for episodic shoaling of anoxic water during Late Permian mass extinction

    PubMed Central

    Shen, Yanan; Farquhar, James; Zhang, Hua; Masterson, Andrew; Zhang, Tonggang; Wing, Boswell A.

    2011-01-01

    Global fossil data show that profound biodiversity loss preceded the final catastrophe that killed nearly 90% marine species on a global scale at the end of the Permian. Many hypotheses have been proposed to explain this extinction and yet still remain greatly debated. Here, we report analyses of all four sulphur isotopes (32S, 33S, 34S and 36S) for pyrites in sedimentary rocks from the Meishan section in South China. We observe a sulphur isotope signal (negative δ34S with negative Δ33S) that may have resulted from limitation of sulphate supply, which may be linked to a near shutdown of bioturbation during shoaling of anoxic water. These results indicate that episodic shoaling of anoxic water may have contributed to the profound biodiversity crisis before the final catastrophe. Our data suggest a prolonged deterioration of oceanic environments during the Late Permian mass extinction. PMID:21343928

  3. Multiple S-isotopic evidence for episodic shoaling of anoxic water during Late Permian mass extinction.

    PubMed

    Shen, Yanan; Farquhar, James; Zhang, Hua; Masterson, Andrew; Zhang, Tonggang; Wing, Boswell A

    2011-01-01

    Global fossil data show that profound biodiversity loss preceded the final catastrophe that killed nearly 90% marine species on a global scale at the end of the Permian. Many hypotheses have been proposed to explain this extinction and yet still remain greatly debated. Here, we report analyses of all four sulphur isotopes ((32)S, (33)S, (34)S and (36)S) for pyrites in sedimentary rocks from the Meishan section in South China. We observe a sulphur isotope signal (negative δ(34)S with negative Δ(33)S) that may have resulted from limitation of sulphate supply, which may be linked to a near shutdown of bioturbation during shoaling of anoxic water. These results indicate that episodic shoaling of anoxic water may have contributed to the profound biodiversity crisis before the final catastrophe. Our data suggest a prolonged deterioration of oceanic environments during the Late Permian mass extinction. PMID:21343928

  4. Early Archaean microorganisms preferred elemental sulfur, not sulfate.

    PubMed

    Philippot, Pascal; Van Zuilen, Mark; Lepot, Kevin; Thomazo, Christophe; Farquhar, James; Van Kranendonk, Martin J

    2007-09-14

    Microscopic sulfides with low 34S/32S ratios in marine sulfate deposits from the 3490-million-year old Dresser Formation, Australia, have been interpreted as evidence for the presence of early sulfate-reducing organisms on Earth. We show that these microscopic sulfides have a mass-independently fractionated sulfur isotopic anomaly (Delta33S) that differs from that of their host sulfate (barite). These microscopic sulfides could not have been produced by sulfate-reducing microbes, nor by abiologic processes that involve reduction of sulfate. Instead, we interpret the combined negative delta34S and positive Delta33S signature of these microscopic sulfides as evidence for the early existence of organisms that disproportionate elemental sulfur. PMID:17872441

  5. Defining fish community structure in Lake Winnipeg using stable isotopes (δ(13)C, δ(15)N, δ(34)S): implications for monitoring ecological responses and trophodynamics of mercury & other trace elements.

    PubMed

    Ofukany, Amy F A; Wassenaar, Leonard I; Bond, Alexander L; Hobson, Keith A

    2014-11-01

    The ecological integrity of freshwater lakes is influenced by atmospheric and riverine deposition of contaminants, shoreline development, eutrophication, and the introduction of non-native species. Changes to the trophic structure of Lake Winnipeg, Canada, and consequently, the concentrations of contaminants and trace elements measured in tissues of native fishes, are likely attributed to agricultural runoff from the 977,800 km(2) watershed and the arrival of non-native zooplankters and fishes. We measured δ(13)C, δ(15)N, and δ(34)S along with concentrations of 15 trace elements in 17 native fishes from the north and south basins of Lake Winnipeg in 2009 and 2010. After adjusting for differences in isotopic baseline values between the two basins, fishes in the south basin had consistently higher δ(13)C and δ(34)S, and lower δ(15)N. We found little evidence of biomagnification of trace elements at the community level, but walleye (Sander vitreus) and freshwater drum (Aplodinotus grunniens) had higher mercury and selenium concentrations with increased trophic position, coincident with increased piscivory. There was evidence of growth dilution of cobalt, copper, manganese, molybdenum, thallium, and vanadium, and bioaccumulation of mercury, which could be explained by increases in algal (and consequently, lake and fish) productivity. We conclude that the north and south basins of Lake Winnipeg represent very different communities with different trophic structures and trace element concentrations. PMID:25129159

  6. Influence of different organic fertilizers on quality parameters and the delta(15)N, delta(13)C, delta(2)H, delta(34)S, and delta(18)O values of orange fruit (Citrus sinensis L. Osbeck).

    PubMed

    Rapisarda, Paolo; Camin, Federica; Fabroni, Simona; Perini, Matteo; Torrisi, Biagio; Intrigliolo, Francesco

    2010-03-24

    To investigate the influence of different types of fertilizers on quality parameters, N-containing compounds, and the delta(15)N, delta(13)C, delta(2)H, delta (34)S, and delta(18)O values of citrus fruit, a study was performed on the orange fruit cv. 'Valencia late' (Citrus sinensis L. Osbeck), which was harvested in four plots (three organic and one conventional) located on the same farm. The results demonstrated that different types of organic fertilizers containing the same amount of nitrogen did not effect important changes in orange fruit quality parameters. The levels of total N and N-containing compounds such as synephrine in fruit juice were not statistically different among the different treatments. The delta(15)N values of orange fruit grown under fertilizer derived from animal origin as well as from vegetable compost were statistically higher than those grown with mineral fertilizer. Therefore, delta(15)N values can be used as an indicator of citrus fertilization management (organic or conventional), because even when applied organic fertilizers are of different origins, the natural abundance of (15)N in organic citrus fruit remains higher than in conventional ones. These treatments also did not effect differences in the delta(13)C, delta(2)H, delta(34)S, and delta(18)O values of fruit. PMID:20184327

  7. Human-Induced Long-Term Shifts in Gull Diet from Marine to Terrestrial Sources in North America's Coastal Pacific: More Evidence from More Isotopes (δ2H, δ34S).

    PubMed

    Hobson, Keith A; Blight, Louise K; Arcese, Peter

    2015-09-15

    Measurements of naturally occurring stable isotopes in tissues of seabirds and their prey are a powerful tool for investigating long-term changes in marine foodwebs. Recent isotopic (δ(15)N, δ(13)C) evidence from feathers of Glaucous-winged Gulls (Larus glaucescens) has shown that over the last 150 years, this species shifted from a midtrophic marine diet to one including lower trophic marine prey and/or more terrestrial or freshwater foods. However, long-term isotopic patterns of δ(15)N and δ(13)C cannot distinguish between the relative importance of lower trophic-level marine foods and terrestrial sources. We examined 48 feather stable-hydrogen (δ(2)H) and -sulfur (δ(34)S) isotope values from this same 150-year feather set and found additional isotopic evidence supporting the hypothesis that gulls shifted to terrestrial and/or freshwater prey. Mean feather δ(2)H and δ(34)S values (± SD) declined from the earliest period (1860-1915; n = 12) from -2.5 ± 21.4 ‰ and 18.9 ± 2.7 ‰, respectively, to -35.5 ± 15.5 ‰ and 14.8 ± 2.4 ‰, respectively, for the period 1980-2009 (n = 12). We estimated a shift of ∼ 30% increase in dependence on terrestrial/freshwater sources. These results are consistent with the hypothesis that gulls increased terrestrial food inputs in response to declining forage fish availability. PMID:26302356

  8. Characterization of magmatic sulfur in the Aegean island arc by means of the δ 34S values of fumarolic H 2S, elemental S, and hydrothermal gypsum from Nisyros and Milos islands

    NASA Astrophysics Data System (ADS)

    Marini, Luigi; Gambardella, Barbara; Principe, Claudia; Arias, Alessia; Brombach, Tatjana; Hunziker, Johannes C.

    2002-06-01

    A δ 34S value of +6.3±1.5‰ was estimated for the rhyodacitic degassing magma present underneath the hydrothermal system of Nisyros, based on the S isotope ratios of H 2S in fumarolic vapors. This value was estimated by modeling the irreversible water-rock mass transfers occurring during the generation of the hydrothermal liquid which separates these fumarolic vapors. The S isotope ratio of the rhyodacitic degassing magma of Nisyros is consistent with fractional crystallization of a parent basaltic magma with an initial δ 34S value of +4‰ (±at least 1.5‰). This positive value could be explained by mantle contamination due to by either transference of fluids derived from subducted materials or involvement of altered oceanic crust, whereas contribution of biogenic sulfides from sediments seems to be negligible or nil. This conclusion agrees with the lack of N 2 and CO 2 from thermal decomposition of organic matter contained in subducted sediments, which is a characteristic of the whole Aegean arc system. Since hydrothermal S at Milos and Santorini has isotope ratios similar to those determined at Nisyros, it seems likely that common controlling processes are active throughout the Aegean island arc.

  9. S-33 constraints on the seawater sulfate contribution in modern seafloor hydrothermal vent sulfides

    NASA Astrophysics Data System (ADS)

    Ono, Shuhei; Shanks, Wayne C.; Rouxel, Olivier J.; Rumble, Douglas

    2007-03-01

    Sulfide sulfur in mid-oceanic ridge hydrothermal vents is derived from leaching of basaltic-sulfide and seawater-derived sulfate that is reduced during high temperature water rock interaction. Conventional sulfur isotope studies, however, are inconclusive about the mass-balance between the two sources because 34S/ 32S ratios of vent fluid H 2S and chimney sulfide minerals may reflect not only the mixing ratio but also isotope exchange between sulfate and sulfide. Here, we show that high-precision analysis of S-33 can provide a unique constraint because isotope mixing and isotope exchange result in different Δ 33S (≡δ 33S-0.515 δ 34S) values of up to 0.04‰ even if δ 34S values are identical. Detection of such small Δ 33S differences is technically feasible by using the SF 6 dual-inlet mass-spectrometry protocol that has been improved to achieve a precision as good as 0.006‰ (2 σ). Sulfide minerals (marcasite, pyrite, chalcopyrite, and sphalerite) and vent H 2S collected from four active seafloor hydrothermal vent sites, East Pacific Rise (EPR) 9-10°N, 13°N, and 21°S and Mid-Atlantic Ridge (MAR) 37°N yield Δ 33S values ranging from -0.002 to 0.033 and δ 34S from -0.5‰ to 5.3‰. The combined δ 34S and Δ 33S systematics reveal that 73 to 89% of vent sulfides are derived from leaching from basaltic sulfide and only 11 to 27% from seawater-derived sulfate. Pyrite from EPR 13°N and marcasite from MAR 37°N are in isotope disequilibrium not only in δ 34S but also in Δ 33S with respect to associated sphalerite and chalcopyrite, suggesting non-equilibrium sulfur isotope exchange between seawater sulfate and sulfide during pyrite precipitation. Seafloor hydrothermal vent sulfides are characterized by low Δ 33S values compared with biogenic sulfides, suggesting little or no contribution of sulfide from microbial sulfate reduction into hydrothermal sulfides at sediment-free mid-oceanic ridge systems. We conclude that 33S is an effective new tracer for

  10. S-33 constraints on the seawater sulfate contribution in modern seafloor hydrothermal vent sulfides

    USGS Publications Warehouse

    Ono, Shuhei; Shanks, Wayne C., III; Rouxel, O.J.; Rumble, D.

    2007-01-01

    Sulfide sulfur in mid-oceanic ridge hydrothermal vents is derived from leaching of basaltic-sulfide and seawater-derived sulfate that is reduced during high temperature water rock interaction. Conventional sulfur isotope studies, however, are inconclusive about the mass-balance between the two sources because 34S/32S ratios of vent fluid H2S and chimney sulfide minerals may reflect not only the mixing ratio but also isotope exchange between sulfate and sulfide. Here, we show that high-precision analysis of S-33 can provide a unique constraint because isotope mixing and isotope exchange result in different ??33S (?????33S-0.515 ??34S) values of up to 0.04??? even if ??34S values are identical. Detection of such small ??33S differences is technically feasible by using the SF6 dual-inlet mass-spectrometry protocol that has been improved to achieve a precision as good as 0.006??? (2??). Sulfide minerals (marcasite, pyrite, chalcopyrite, and sphalerite) and vent H2S collected from four active seafloor hydrothermal vent sites, East Pacific Rise (EPR) 9-10??N, 13??N, and 21??S and Mid-Atlantic Ridge (MAR) 37??N yield ??33S values ranging from -0.002 to 0.033 and ??34S from -0.5??? to 5.3???. The combined ??34S and ??33S systematics reveal that 73 to 89% of vent sulfides are derived from leaching from basaltic sulfide and only 11 to 27% from seawater-derived sulfate. Pyrite from EPR 13??N and marcasite from MAR 37??N are in isotope disequilibrium not only in ??34S but also in ??33S with respect to associated sphalerite and chalcopyrite, suggesting non-equilibrium sulfur isotope exchange between seawater sulfate and sulfide during pyrite precipitation. Seafloor hydrothermal vent sulfides are characterized by low ??33S values compared with biogenic sulfides, suggesting little or no contribution of sulfide from microbial sulfate reduction into hydrothermal sulfides at sediment-free mid-oceanic ridge systems. We conclude that 33S is an effective new tracer for interplay among

  11. Multiple sulfur isotope evidence for massive oceanic sulfate depletion in the aftermath of Snowball Earth

    NASA Astrophysics Data System (ADS)

    Sansjofre, Pierre; Cartigny, Pierre; Trindade, Ricardo I. F.; Nogueira, Afonso C. R.; Agrinier, Pierre; Ader, Magali

    2016-07-01

    The terminal Neoproterozoic Era (850-542 Ma) is characterized by the most pronounced positive sulfur isotope (34S/32S) excursions in Earth's history, with strong variability and maximum values averaging δ34S~+38‰. These excursions have been mostly interpreted in the framework of steady-state models, in which ocean sulfate concentrations do not fluctuate (that is, sulfate input equals sulfate output). Such models imply a large pyrite burial increase together with a dramatic fluctuation in the isotope composition of marine sulfate inputs, and/or a change in microbial sulfur metabolisms. Here, using multiple sulfur isotopes (33S/32S, 34S/32S and 36S/32S ratios) of carbonate-associated sulfate, we demonstrate that the steady-state assumption does not hold in the aftermath of the Marinoan Snowball Earth glaciation. The data attest instead to the most impressive event of oceanic sulfate drawdown in Earth's history, driven by an increased pyrite burial, which may have contributed to the Neoproterozoic oxygenation of the oceans and atmosphere.

  12. The promoter effect and a rate expression of the catalytic incineration of (CH3)2S2 over an improved CuO-MoO3/gamma-Al2O3 catalyst.

    PubMed

    Wang, Ching-Huei; Lin, Shiow-Shyung; Liou, Shen-Ben; Weng, Hung-Shan

    2002-10-01

    The CuO-MoO3/gamma-Al2O3 catalyst, confirmed previously as having good activity in the catalytic incineration of (CH3)2S2, was employed as the principal catalyst in this study. With the aim of improving catalyst activity and resistance to deactivation by sulfur compounds, a promoter was added either before adding the precursors of Cu and Mo or together with Cu and Mo onto the gamma-Al2O3. Promoters included transition metals and elements from groups IA-VIIA in the chemical periodic table. Experimental results reveal Cr2O3 as the most effective promoter, with an optimal composition of 5 wt.% Cu, 6 wt.% Mo and 4 wt.% Cr (designated as Cu(5)-Mo(6)-Cr(4)/gamma-Al2O3). Knowing that higher acidity can improve activity, we further investigated the effect of acid treatment on the performance of the Cu(5)-Mo(6)-Cr(4)/gamma-Al2O3 catalyst. Experimental results indicate the H2SO4-treated catalyst (Cu(5)-Mo(6)-Cr(4)/sulfated-gamma-Al2O3) has a better activity and durability. A study for finding an appropriate rate expression for the catalytic incineration of (CH3)2S2 by Cu(5)-Mo(6)-Cr(4)/sulfated-gamma-Al2O3 was carried out in a differential reactor. The results show that the Mars-Van Krevelen model is applicable to this destructive oxidation reaction. Results additionally reveal that competitive adsorption of CH4 reduces conversion of (CH3)2S2. PMID:12365836

  13. Applying Statement 34's Capital Asset Requirements.

    ERIC Educational Resources Information Center

    Finden, Randal

    2001-01-01

    Discusses common issues and offers recommendations related to revisions in Governmental Accounting Standards Board Statement 34 wherein the financial reporting of the general fixed-assets account group is eliminated and instead a school district's general capital assets are reported and depreciated on the new statement of net assets and statement…

  14. The Accuracy of Measurements of the Spectral-Line Frequencies in the Studies of the Rotational Transitions of the 16O12C32S Molecule in the Millimeter and Submillimeter Wave Ranges

    NASA Astrophysics Data System (ADS)

    Golubiatnikov, G. Yu; Belov, S. P.; Lapinov, A. V.

    2016-01-01

    The absolute error of determining the center frequency of the molecule spectral line during a single measurement, which is obtained by fitting the line shape to the model profile, is usually significantly smaller than the statistical spread in the frequencies of the repeated measurements. We discuss the possible causes of the systematic errors leading to an increase in the uncertainty of measurements of the line-center frequency. For an example of the multiple spectral measurements of the rotational transitions of the 16O12C32S molecule in the millimeter- and submillimeter-wave ranges (with a frequency of up to 522 GHz), by the Lamb-dip method, we determine the absolute error of the performed measurements, which amounts to 0 .4 kHz. New precision values of the center frequencies of the rotational transitions of the 16O12C32S molecule and more accurate values of the rotational constants, which are calculated using the measured frequencies, are presented.

  15. [Using delta34S-SO4(2-) and Delta15N-NO3-, delta18O-NO3- to Trace the Sources of Sulfur and Nitrate in Lihu Lake Undergound Water, Guangxi, China].

    PubMed

    Li, Rui; Xiao, Qiong; Liu, Wen; Guo, Fang; Pan, Mou-cheng; Yu, Shi

    2015-08-01

    To reveal the temporal and spatial variation pattern of groundwater chemistry in Lihu Lake and explore the causes for the change of water quality through analysis of sulfur isotope and nitrogen-oxygen isotope, so as to provide scientific basis for reasonable exploitation and protection of karst water resources. Several groundwater samples, collected from January to December in 2010 and May, October in 2014 were monitored to analyze the chemical composition of conventional water and the characteristics of delta34S-SO4(2-), and delta15N-NO3-. The results showed that: (1) The hydrochemical type of the underground water was HCO3-Ca type and effected by the seasonal precipitation and human activity, the temporal and spatial variation of the main cations was obvious. (2) The sulfur concentration in the underground river was slightly decreased since the operation of the sewage plant, however, the sulfur concentration was still high. The nitrate pollution aggravated in the year 2014 compared to 2010. Impacted by human activity, the concentration of sulfur and nitrate was higher in the upstream Nandan river, Layi cave and the midstream Liangfeng cave, and Gantianba than in the downstream Xiaolong cave. (3) The delta34S-SO4(2-) value ranged from -4.12%o to -0.93%o. It was inferred that the emission of sulfur oxides through burning coal resulted in the rainwater acidification, which input a large amount of SO4(2-) into the underground water in the form of acid rain. (4) The delta15N-N03- value ranged from 0.26%o to 11.58%o, with an average value of 7.61%o, the delta18O-NO3- value ranged from -2.33%o to 21.76%o, with an average value of 9.38%o. In combination of the composition analysis of nitrogen-oxygen isotope of nitrate, it was believed that soil organic nitrogen, manure and sewage were the main sources of nitrate in the groundwater and the main causes for aggravation of nitrate pollution of the underground water. PMID:26592016

  16. Sulphur tales from the early Archean world

    NASA Astrophysics Data System (ADS)

    Montinaro, A.; Strauss, H.

    2016-07-01

    Sedimentary and magmatic rocks and their distinct sulphur isotopic signatures indicate the sources and processes of sulphur cycling, in particular through the analysis of all four stable sulphur isotopes (32S, 33S, 34S and 36S). Research over the past 15 years has substantially advanced our understanding of sulphur cycling on the early Earth, most notably through the discovery of mass-independently fractionated sulphur isotopic signatures. A strong atmospheric influence on the early Archean global sulphur cycle is apparent, much in contrast to the modern world. Diverse microbially driven sulphur cycling is clearly discernible, but its importance for Earth surface environments remains to be quantified.

  17. Calibrated sulfur isotope abundance ratios of three IAEA sulfur isotope reference materials and V-CDT with a reassessment of the atomic weight of sulfur

    NASA Astrophysics Data System (ADS)

    Ding, T.; Valkiers, S.; Kipphardt, H.; De Bièvre, P.; Taylor, P. D. P.; Gonfiantini, R.; Krouse, R.

    2001-09-01

    Calibrated values have been obtained for sulfur isotope abundance ratios of sulfur isotope reference materials distributed by the IAEA (Vienna). For the calibration of the measurements, a set of synthetic isotope mixtures were prepared gravimetrically from high purity Ag 2S materials enriched in 32S, 33S, and 34S. All materials were converted into SF 6 gas and subsequently, their sulfur isotope ratios were measured on the SF 5+ species using a special gas source mass spectrometer equipped with a molecular flow inlet system (IRMM's Avogadro II amount comparator). Values for the 32S/ 34S abundance ratios are 22.650 4(20), 22.142 4(20), and 23.393 3(17) for IAEA-S-1, IAEA-S-2, and IAEA-S-3, respectively. The calculated 32S/ 34S abundance ratio for V-CDT is 22.643 6(20), which is very close to the calibrated ratio obtained by Ding et al. (1999). In this way, the zero point of the VCDT scale is anchored firmly to the international system of units SI. The 32S/ 33S abundance ratios are 126.942(47), 125.473(55), 129.072(32), and 126.948(47) for IAEA-S-1, IAEA-S-2, IAEA-S-3, and V-CDT, respectively. In this way, the linearity of the V-CDT scale is improved over this range. The values of the sulfur molar mass for IAEA-S-1 and V-CDT were calculated to be 32.063 877(56) and 32.063 911(56), respectively, the values with the smallest combined uncertainty ever reported for the sulfur molar masses (atomic weights).

  18. Mass-dependent sulfur isotope fractionation during reoxidative sulfur cycling: A case study from Mangrove Lake, Bermuda

    NASA Astrophysics Data System (ADS)

    Pellerin, André; Bui, Thi Hao; Rough, Mikaella; Mucci, Alfonso; Canfield, Donald E.; Wing, Boswell A.

    2015-01-01

    The multiple sulfur isotope composition of porewater sulfate from the anoxic marine sapropel of Mangrove Lake, Bermuda was measured in order to establish how multiple sulfur isotopes are fractionated during reoxidative sulfur cycling. The porewater-sulfate δ34S and Δ33S dataset exhibits the distinct isotopic signatures of microbial sulfate reduction and sulfur reoxidation. We reproduced the measurements with a simple diagenetic model that yielded fractionation factors for net sulfate removal of between -29.2‰ and -32.5‰. A new approach to isotopic modeling of the sulfate profiles, informed by the chemistry of sulfur intermediate compounds in Mangrove Lake, reveals that sulfate reduction produces a relatively small intrinsic fractionation and that an active reoxidative sulfur cycle increases the fractionation of the measured values. Based on the model results, the reoxidative cycle of Mangrove Lake appears to include sulfide oxidation to elemental sulfur followed by the disproportionation of the elemental sulfur to sulfate and sulfide. This model also indicates that the reoxidative sulfur cycle of Mangrove Lake turns over from 50 to 80% of the sulfide produced by microbial sulfate reduction. The Mangrove Lake case study shows how sulfur isotope fractionations can be separated into three different "domains" in Δ33S34S space based on their ability to resolve reductive and reoxidative sulfur transformations. The first domain that differentiates reductive and reoxidative sulfur cycling is well illustrated by previous studies and requires 34S-32S fractionations more negative than ≈-70‰, beyond the fractionation limit of microbial sulfate reduction at earth surface temperatures. The second domain that distinguishes reductive and reoxidative processes is between 34S-32S fractionations of -40‰ and 0‰, where the 33S-32S fractionations of sulfate reduction and reoxidation are significantly different. In the remaining domain (between 34S-32S fractionations

  19. Tissue S/N ratios and stable isotopes (delta(34)S and delta(15)N) of epilithic mosses (Haplocladium microphyllum) for showing air pollution in urban cities in Southern China.

    PubMed

    Xiao, Hua-Yun; Tang, Cong-Guo; Xiao, Hong-Wei; Wang, Yan-Li; Liu, Xue-Yan; Liu, Cong-Qiang

    2010-05-01

    In urban cities in Southern China, the tissue S/N ratios of epilithic mosses (Haplocladium microphyllum), varied widely from 0.11 to 0.19, are strongly related to some atmospheric chemical parameters (e.g. rainwater SO(4)(2-)/NH(4)(+) ratios, each people SO(2) emission). If tissue S/N ratios in the healthy moss species tend to maintain a constant ratio of 0.15 in unpolluted area, our study cities can be divided into two classes: class I (S/N > 0.15, S excess) and class II (S/N < 0.15, N excess), possibly indicative of stronger industrial activity and higher density of population, respectively. Mosses in all these cities obtained S and N from rainwater at a similar ratio. Sulphur and N isotope ratios in mosses are found significantly linearly correlated with local coal delta(34)S and NH(4)(+)-N wet deposition, respectively, indicating that local coal and animal NH(3) are the major atmospheric S and N sources. PMID:19959268

  20. High resolution analysis of the rotational levels of the (0 0 0), (0 1 0), (1 0 0), (0 0 1), (0 2 0), (1 1 0) and (0 1 1) vibrational states of 34S16O2

    SciTech Connect

    Lafferty, Walter; Flaud, Jean-marie; Sams, Robert L.; Ngom, El Hadji A.

    2008-11-01

    A high resolution (0.0018 cm-1) Fourier transform instrument has been used to record the spectrum of an enriched 34S (95.3 %) sample of sulfur dioxide. A thorough analysis of the ν2, 2ν2 - ν2 , ν1, ν1 + ν2 - ν2, ν3, ν2 + ν3 - ν2, ν1 + ν2 and ν2 + ν3 bands has been carried out leading to a large set of assigned lines. From these lines ground state combination differences were obtained and fitted together with the existing microwave, millimeter, and terahertz rotational lines. An improved set of ground state rotational constants were obtained. Next, the upper state rotational levels were fitted. For the (010), (110), (011) states, a simple Watson type Hamilton sufficed. However, it was necessary to include explicitly interacting terms in the Hamiltonian matrix in order to fit the rotational levels of the (020), (100) and (101) states to within their experimental accuracy. More explicitly, it was necessary to use a ΔK=2 term to model the Fermi interaction between the (020) and (100) levels and a ΔK=3 term to model the Coriolis interaction between the (100) and (001) levels. Precise Hamiltonian constants were derived for the (000), (010), (100), (001), (020), (110) and (011) vibrational states.

  1. Combined S-33 and O-18 Isotope Tracing of Intracellular Sulfur Metabolism during Microbial Sulfate Reduction

    NASA Astrophysics Data System (ADS)

    Antler, Gilad; Bosak, Tanja; Ono, Shuhei; Sivan, Orit; Turchyn, Alexandra V.

    2014-05-01

    Microbial sulfate reduction is a key player in the global carbon cycle, oxidizing nearly 50% of organic matter in marine sediments. The biochemical pathway of microbial sulfate reduction fractionates sulfur and oxygen isotopes and these fractionations can be used to reconstruct S cycling in sediments. Sulfur isotope fractionation during microbial sulfate reduction, which partitions lighter sulfur (32S) into sulfide and heavier sulfur (33S and 34S) into the residual sulfate, can be as high as 72o for 34S/32S. The availability and type of organic substrate control the magnitude of sulfur isotope fractionation by influencing the fluxes of and the transfer of electrons to different S species. The partitioning of oxygen in sulfate during microbial sulfate reduction appears to be strongly influenced by the oxygen isotopic composition of water in which the bacteria grow, but its magnitude also seems to correlate with the magnitude of 34S/32S isotope fractionation. In addition, the fractionation of 33S/32S is thought to reflect the reversibility of some intercellular fluxes. We wanted to investigate whether the 18O/16O, 34S/32S and 33S/32S isotope fractionations in sulfate are controlled by the same intracellular processes and conditions. This was done by investigating the combined sulfur and oxygen isotope partitioning by a marine Desulfovibrio sp. grown in pure culture on different organic substrates and in water with different isotopic composition of oxygen. The isotope fractionations of oxygen and sulfur correlated with the cell specific sulfate reduction rates (csSRR), where slower rates yielded higher sulfur fractionation (as high as 60) and higher oxygen isotope fractionation. The trends in 33S/32S and 34S/32S with the changing csSRR was similar to the trends in 18O/16O with the csSRR, suggesting that the same intercellular pathways controlled both oxygen and sulfur isotope signatures during microbial sulfate reduction. The use of water with different isotopic

  2. Multiple sulfur isotope evidence for massive oceanic sulfate depletion in the aftermath of Snowball Earth.

    PubMed

    Sansjofre, Pierre; Cartigny, Pierre; Trindade, Ricardo I F; Nogueira, Afonso C R; Agrinier, Pierre; Ader, Magali

    2016-01-01

    The terminal Neoproterozoic Era (850-542 Ma) is characterized by the most pronounced positive sulfur isotope ((34)S/(32)S) excursions in Earth's history, with strong variability and maximum values averaging δ(34)S∼+38‰. These excursions have been mostly interpreted in the framework of steady-state models, in which ocean sulfate concentrations do not fluctuate (that is, sulfate input equals sulfate output). Such models imply a large pyrite burial increase together with a dramatic fluctuation in the isotope composition of marine sulfate inputs, and/or a change in microbial sulfur metabolisms. Here, using multiple sulfur isotopes ((33)S/(32)S, (34)S/(32)S and (36)S/(32)S ratios) of carbonate-associated sulfate, we demonstrate that the steady-state assumption does not hold in the aftermath of the Marinoan Snowball Earth glaciation. The data attest instead to the most impressive event of oceanic sulfate drawdown in Earth's history, driven by an increased pyrite burial, which may have contributed to the Neoproterozoic oxygenation of the oceans and atmosphere. PMID:27447895

  3. Multiple sulfur isotope evidence for massive oceanic sulfate depletion in the aftermath of Snowball Earth

    PubMed Central

    Sansjofre, Pierre; Cartigny, Pierre; Trindade, Ricardo I. F.; Nogueira, Afonso C. R.; Agrinier, Pierre; Ader, Magali

    2016-01-01

    The terminal Neoproterozoic Era (850–542 Ma) is characterized by the most pronounced positive sulfur isotope (34S/32S) excursions in Earth's history, with strong variability and maximum values averaging δ34S∼+38‰. These excursions have been mostly interpreted in the framework of steady-state models, in which ocean sulfate concentrations do not fluctuate (that is, sulfate input equals sulfate output). Such models imply a large pyrite burial increase together with a dramatic fluctuation in the isotope composition of marine sulfate inputs, and/or a change in microbial sulfur metabolisms. Here, using multiple sulfur isotopes (33S/32S, 34S/32S and 36S/32S ratios) of carbonate-associated sulfate, we demonstrate that the steady-state assumption does not hold in the aftermath of the Marinoan Snowball Earth glaciation. The data attest instead to the most impressive event of oceanic sulfate drawdown in Earth's history, driven by an increased pyrite burial, which may have contributed to the Neoproterozoic oxygenation of the oceans and atmosphere. PMID:27447895

  4. Atmospheric record in the Hadean Eon from multiple sulfur isotope measurements in Nuvvuagittuq Greenstone Belt (Nunavik, Quebec).

    PubMed

    Thomassot, Emilie; O'Neil, Jonathan; Francis, Don; Cartigny, Pierre; Wing, Boswell A

    2015-01-20

    Mass-independent fractionation of sulfur isotopes (S-MIF) results from photochemical reactions involving short-wavelength UV light. The presence of these anomalies in Archean sediments [(4-2.5 billion years ago, (Ga)] implies that the early atmosphere was free of the appropriate UV absorbers, of which ozone is the most important in the modern atmosphere. Consequently, S-MIF is considered some of the strongest evidence for the lack of free atmospheric oxygen before 2.4 Ga. Although temporal variations in the S-MIF record are thought to depend on changes in the abundances of gas and aerosol species, our limited understanding of photochemical mechanisms complicates interpretation of the S-MIF record in terms of atmospheric composition. Multiple sulfur isotope compositions (δ(33)S, δ(34)S, and δ(36)S) of the >3.8 billion-year-old Nuvvuagittuq Greenstone Belt (Ungava peninsula) have been investigated to track the early origins of S-MIF. Anomalous S-isotope compositions (Δ(33)S up to +2.2‰) confirm a sedimentary origin of sulfide-bearing banded iron and silica-rich formations. Sharp isotopic transitions across sedimentary/igneous lithological boundaries indicate that primary surficial S-isotope compositions have been preserved despite a complicated metamorphic history. Furthermore, Nuvvuagittuq metasediments recorded coupled variations in (33)S/(32)S, (34)S/(32)S, and (36)S/(32)S that are statistically indistinguishable from those identified several times later in the Archean. The recurrence of the same S-isotope pattern at both ends of the Archean Eon is unexpected, given the complex atmospheric, geological, and biological pathways involved in producing and preserving this fractionation. It implies that, within 0.8 billion years of Earth's formation, a common mechanism for S-MIF production was established in the atmosphere. PMID:25561552

  5. Atmospheric record in the Hadean Eon from multiple sulfur isotope measurements in Nuvvuagittuq Greenstone Belt (Nunavik, Quebec)

    PubMed Central

    Thomassot, Emilie; O’Neil, Jonathan; Francis, Don; Cartigny, Pierre; Wing, Boswell A.

    2015-01-01

    Mass-independent fractionation of sulfur isotopes (S-MIF) results from photochemical reactions involving short-wavelength UV light. The presence of these anomalies in Archean sediments [(4–2.5 billion years ago, (Ga)] implies that the early atmosphere was free of the appropriate UV absorbers, of which ozone is the most important in the modern atmosphere. Consequently, S-MIF is considered some of the strongest evidence for the lack of free atmospheric oxygen before 2.4 Ga. Although temporal variations in the S-MIF record are thought to depend on changes in the abundances of gas and aerosol species, our limited understanding of photochemical mechanisms complicates interpretation of the S-MIF record in terms of atmospheric composition. Multiple sulfur isotope compositions (δ33S, δ34S, and δ36S) of the >3.8 billion-year-old Nuvvuagittuq Greenstone Belt (Ungava peninsula) have been investigated to track the early origins of S-MIF. Anomalous S-isotope compositions (Δ33S up to +2.2‰) confirm a sedimentary origin of sulfide-bearing banded iron and silica-rich formations. Sharp isotopic transitions across sedimentary/igneous lithological boundaries indicate that primary surficial S-isotope compositions have been preserved despite a complicated metamorphic history. Furthermore, Nuvvuagittuq metasediments recorded coupled variations in 33S/32S, 34S/32S, and 36S/32S that are statistically indistinguishable from those identified several times later in the Archean. The recurrence of the same S-isotope pattern at both ends of the Archean Eon is unexpected, given the complex atmospheric, geological, and biological pathways involved in producing and preserving this fractionation. It implies that, within 0.8 billion years of Earth’s formation, a common mechanism for S-MIF production was established in the atmosphere. PMID:25561552

  6. Precise isotope-ratio determination by CGC hyphenated to ICP-MCMS for speciation of trace amounts of gaseous sulfur, with SF6 as example compound.

    PubMed

    Krupp, Eva M; Pécheyran, Christophe; Meffan-Main, Simon; Donard, Olivier F X

    2004-01-01

    Capillary gas chromatography coupled to an inductively coupled plasma mass spectrometer with multiple-collector detection (GC-ICP-MCMS) has been used to assess the precision and instrumental mass bias in sulfur isotope-ratio determination for the gaseous sulfur species SF6. The isotopic composition of the compound was certified by the institute for reference materials and measurements (IRMM, Belgium) and is available as PIGS 2010. Integration of the peaks (peak half-width 1.4 s) was performed using a special peak-integration method based on definition of the integration area by assessment of a uniform isotope-ratio area within the chromatographic peak. Instrumental mass bias was determined to be approximately 12% per mass unit and proved to be stable in the concentration range measured. Replicate injections of 2, 10, 20, and 30 ng (as S) SF6 diluted in argon gave precision for the 32S/34S ratio from 0.6% RSD for 2-ng injections to 0.03% RSD for 30-ng injections. The 32S/33S and 33S/34S isotope-ratio precision was better than 0.4% RSD for injections of 10 ng (as S) and higher. Detection limits were in the absolute pg range for all measured sulfur isotopes. PMID:14618293

  7. Pyrolysis of sulfur tetrafluoride over boron: Excited-state rotational spectra and equilibrium structure of fluorothioborine (FBS)

    NASA Astrophysics Data System (ADS)

    Bizzocchi, L.; Esposti, C. Degli

    2001-10-01

    The unstable FBS molecule has been produced in the gas phase by a high-temperature reaction between crystalline boron and sulfur tetrafluoride. Its rotational spectrum has been observed in the millimeter-wave region, from 75 to 460 GHz, for different isotopic species and vibrational states. All the excited states which approximately lie below 1700 cm-1, that are 1000 (F-B stretch), 0110 (FBS bend), 0001 (B=S stretch), 2000, 0200, 0220, 0310, 0330, 0400, 0420, 0440, 1110, 1200, and 1220, have been investigated for the most abundant isotopomer F11B32S. The analysis of the spectra has been performed taking simultaneously into account the Fermi interaction which couples the states ν1,ν2,ν3 with ν1-1, ν2+2,ν3, and l-type resonances between different sublevels of a given vibrational bending state. This procedure allowed us to calculate directly deperturbed parameters and, in addition, yielded reliable estimates of the vibrational energy difference between the interacting levels and of the normal coordinate cubic force constant k122. Rotational spectra in the ground and various excited states have been also recorded and analyzed for the less abundant isotopic species F10B32S, F11B34S, F10B34S, F11B33S, and F10B33S. The very weak spectrum in the 0001 state was successfully observed for the pair of isotopomers F11B32S and F10B32S, whose equilibrium rotational constants could be accurately calculated yielding the first evaluation of the equilibrium structure of fluorothioborine: re(F-B)=1.2762±0.0002 Å and re(B=S)=1.6091±0.0002 Å.

  8. Dynamical cluster-decay model for hot and rotating light-mass nuclear systems applied to the low-energy {sup 32}S+{sup 24}Mg{yields}{sup 56}Ni{sup *} reaction

    SciTech Connect

    Gupta, Raj K.; Kumar, Rajesh; Singh, Dalip; Balasubramaniam, M.; Beck, C.

    2005-01-01

    The dynamical cluster-decay model (DCM) is developed further for the decay of hot and rotating compound nuclei (China) formed in light heavy-ion reactions. The model is worked out in terms of only one parameter, namely the neck-length parameter, which is related to the total kinetic energy TKE(T) or effective Q value Q{sub eff}(T) at temperature T of the hot CN and is defined in terms of the CN binding energy and ground-state binding energies of the emitted fragments. The emission of both the light particles (LP), with A{<=}4,Z{<=}2, as well as the complex intermediate mass fragments (IMF), with 42, is considered as the dynamical collective mass motion of preformed clusters through the barrier. Within the same dynamical model treatment, the LPs are shown to have different characteristics compared to those of the IMFs. The systematic variations of the LP emission cross section {sigma}{sub LP} and IMF emission cross section {sigma}{sub IMF} calculated from the present DCM match exactly the statistical fission model predictions. A nonstatistical dynamical description is developed for the first time for emission of light particles from hot and rotating CN. The model is applied to the decay of {sup 56}Ni* formed in the {sup 32}S+{sup 24}Mg reaction at two incident energies E{sub c.m.}=51.6 and 60.5 MeV. Both the IMFs and average TKE{sup lowbar} spectra are found to compare resonably well with the experimental data, favoring asymmetric mass distributions. The LPs' emission cross section is shown to depend strongly on the type of emitted particles and their multiplicities.

  9. Positron emission tomography experience with 2-[¹⁸F]fluoro-3-(2(S)-azetidinylmethoxy)pyridine (2-[¹⁸F]FA) in the living human brain of smokers with paranoid schizophrenia.

    PubMed

    Brašić, James Robert; Cascella, Nicola; Kumar, Anil; Zhou, Yun; Hilton, John; Raymont, Vanessa; Crabb, Andrew; Guevara, Maria Rita; Horti, Andrew G; Wong, Dean Foster

    2012-04-01

    Utilizing postmortem data (Breese et al. [2000] Neuropsychopharmacology 23:351-364), we hypothesized that the densities of high-affinity neuronal α4β2 nicotinic acetylcholine receptors (nAChRs) in the brain exist in a continuum from highest to lowest as follows: smokers without schizophrenia > smokers with schizophrenia > nonsmokers without schizophrenia > nonsmokers with schizophrenia. Application of the Kruskal-Wallis Test (Statacorp, 2003) to the postmortem data (Breese et al. [2000] Neuropsychopharmacology 23:351-364) confirmed the hypothesized order in the cortex and the hippocampus and attained significance in the caudate and the thalamus. Positron emission tomography (PET) was performed for 60 min at 6 h after the intravenous administration of 444 megabequerels [MBq] (12 mCi) 2-[¹⁸F]fluoro-3-(2(S)-azetidinylmethoxy)pyridine (2-[¹⁸F]FA), a radiotracer for high-affinity neuronal α4β2 nAChRs, as a bolus plus continuous infusion to 10 adults (seven men and three women) (six smokers including five with paranoid schizophrenia and four nonsmokers) ranging in age from 22 to 56 years (mean 40.1, standard deviation 13.6). The thalamic nondisplaceable binding potential (BP(ND) ) was 1.32 ± 0.19 (mean ± standard deviation) for healthy control nonsmokers; 0.50 ± 0.19 for smokers with paranoid schizophrenia; and 0.51 for the single smoker without paranoid schizophrenia. The thalamic BP(ND) s of nonsmokers were significantly higher than those of smokers who smoked cigarettes a few hours before the scans (P = 0.0105) (StataCorp, 2003), which was likely due to occupancy of nAChRs by inhaled nicotine in smokers. Further research is needed to rule out the effects of confounding variables. PMID:22169936

  10. Triple isotope composition of sulfur from sulfate on the MC-ICPMS Neptune

    NASA Astrophysics Data System (ADS)

    Paris, G.; Adkins, J. F.; Sessions, A. L.; Subhas, A.; Waldbauer, J.; Fischer, W. W.

    2011-12-01

    We present a new method to measure precise and accurate 34S/32S and 33S/32S ratios from small amounts of sulfate in solution. The sulfur cycle plays an important role in many earth system processes at a variety of timescales. Exploring the isotopic composition of sulfur from Carbonate Associated Sulfates (CAS) during geological times or from dissolved sulfate in modern seawater and porewater can provide important constraints on these processes. For carbonates, existing methods focus on samples rather rich in CAS (>100 ppm) or samples available in large amounts (>1g). Samples with either very low sulfate concentration (e.g., Archean-aged carbonates) and/or limited sample sizes (such as foraminifera) require a more sensitive analytical method. An attractive technique involves MC-ICPMS (multiCollector inductively-coupled plasma mass spectrometry), which has been used successfully for bulk and in-situ δ34S evaluation of sulfate and sulfide minerals (Craddock et al., 2008) and organic compounds (Amrani et al., 2009). Two main advantages of working with a MC-ICPMS (here a ThermoScientific Neptune) compared to conventional SO2 gas source mass spectrometry are an increased sensitivity and the ability to introduce sulfur as either sulfate or sulfide. However, this approach requires removal of the complex sample matrix so samples can be analyzed as sodium sulfate diluted in 5% HNO3. IAEA BaSO4 standards, on the other hand, can be run as dissolved BaSO4 through chelation of Ba with EDTA. Sample purification is achieved through Ca++ removal using either a cation-exchanging membrane or a micro-column of Dionex AG50X8 resin. These two methods allow exchange of Ca++ (or other cations) for H++. Sulfate can then be concentrated by evaporation for subsequent isotope analysis. The membrane is preferred for samples with sulfate concentrations lower than 100 ppm to decrease sulfur contamination from the AG50X8 sulfonyl groups and the resin is favored for samples with sulfate

  11. Triple isotope composition of sulfur from nanomoles of dissolved sulfate on the MC-ICPMS Neptune (Invited)

    NASA Astrophysics Data System (ADS)

    Paris, G.; Sessions, A. L.; Subhas, A. V.; Adkins, J. F.

    2013-12-01

    Over the last decade, the increasing use of Inductively-Coupled plasma mass spectrometer (ICPMS) for measuring the isotopic composition of sulfur helped decreasing significantly the detection limit for analyzing dissolved sulfate, with no loss of precision. Because of intereferences on mass 33 and 36, only the two major isotopes were analyzed. Here, we present a new method to measure precise and accurate 34S /32S and 33S /32S ratios from sulfate in solution. Understanding past and modern sulfur cycle is crucial on many points of view and exploring the isotopic composition of sulfur from Carbonate Associated Sulfate (CAS) during geological times or sulfate from seawater or porewaters provide essential information. For carbonates, existing methods focus on samples rather rich in CAS (>100 ppm) or samples available in important amounts (> 1g). Samples with either very low sulfate concentration (Archean carbonates or continental waters, for instance) and/or samples with limited available amounts (such as foraminifera) require a new analytical method. Isotopic composition of many trace components are successfully measured on MC-ICPMS (MultiCollector ICPMS). The ThermoScientific magnetic sector ICPMS Neptune has already been used successfully for bulk and in-situ δ34S evaluation of sulfate and sulfide minerals [1] and organic compounds [2]. Isotopic composition measurement on the Neptune requires however removal of the complex matrix of the samples so that samples are analyzed as sodium sulfate diluted in 5% HNO3. Sulfate is purified using the AG1X8 anionic resin to remove cations. Because sulfate is not volatile at low temperatures, we use a desolvating membrane (Aridus, Cetac) in order to decrease the various oxygen and S-H interferences on the sulfur peaks. Working at High Resolution (M/ΔM=10000), 32S-H interferences can be resolved and the 33S signal can be measured on an interference-free narrow shoulder. This method allows 34S /32S and 33S /32S ratios measurement

  12. Sulfur Mass-Independent Fractionation in Atmospheric Formation of Volcanic Sulfate

    NASA Astrophysics Data System (ADS)

    Lanciki, A.; Cole-Dai, J.; Thiemens, M. H.; Savarino, J. P.

    2009-12-01

    Volcanic eruptions emit sulfur dioxide which oxidizes to sulfuric acid aerosols in the atmosphere. Sulfate aerosols affect global climate by altering the atmospheric radiative properties. Sulfate aerosols from stratospheric eruptions can impact global climate, through their widespread distribution and relatively long atmospheric residence times (months to years). Ice cores volcanic sulfate records are often used to assess the volcanic contribution to climate change. However, sulfate signals of tropospheric eruptions in the ice core records make it difficult to evaluate the climatic impact of stratospheric eruptions in a glaciological record. But, the isotope composition of the volcanic sulfate can be used to distinguish between sulfate from stratospheric eruptions and that of tropospheric eruptions. Mass-independent fractionation (MIF) of sulfur isotopes in sulfate aerosols arises from the high-energy UV photo-oxidation of SO2, and this can be used to determine if a volcanic eruption is stratospheric, since high-energy UV is available only in the stratosphere. The stable isotopes of sulfur are compared to a standard (Canyon Diablo Triolite, FeS) in equation 1. The small delta (δ) represents the ratio of the isotope of interest to the most abundant isotope.

    δxS (‰) = [(xS/32S)sample/ [(xS/32S)std - 1] × 1000 (1)33S, calculated with the equation below. Any significant, non-zero Δ33S values indicate that the sulfate is formed via the UV-catalyzed oxidation of SO2 in the stratosphere.
    Δ33S = δ33S - 1000 × [(1 + δ34S/1000)0.515 - 1] (2)33S MIF values and have been deemed stratospheric events by this study. The 1259 AD eruption has the largest Δ33S values ever reported, beginning at +1.63 ‰ and ending with -1.49 ‰. Tambora, which has been estimated to be 2-3 times smaller in magnitude than the 1259 event, had measured Δ33S values of +0.25 ‰ to -0.28 ‰ along the timeframe of the eruption. Two of the measured events did not exhibit any

  13. Rare Isotope Insights into Supereruptions: Rare Sulfur and Triple Oxygen Isotope Geochemistry of Stratospheric Sulfate Aerosols Absorbed on Volcanic Ash Particles

    NASA Astrophysics Data System (ADS)

    Bindeman, I. N.; Eiler, J.; Wing, B.; Farquhar, J.

    2006-12-01

    We present analyses of stable isotopic ratios of 17O/16O, 18O/16O, 34S/32S, and 33S/32S, 36S/32S of sulfate leached from volcanic ash of a series of well-known volcanic eruptions. This list covers much of the diversity of sizes and the character of volcanic eruptions. Particular emphasis is paid to the Lava Creek Tuff of Yellowstone and we present wide geographic sample coverage for this unit. This global dataset spans a significant range in δ34S, δ18O, and Δ17O of sulfate (29, 30 and 3.3 permil respectively) with oxygen isotopes recording mass-independent fractionation and sulfur isotopes exhibiting mass-dependent behavior. These ranges are defined by the isotopic compositions of products of large caldera forming eruptions. Proximal ignimbrites and coarse ash typically do not contain sulfate. The presence of sulfate with Δ17O > 0.2 permil is characteristic of small distal ash particles, suggesting that sulfate aerosols were scavenged after they underwent atmospheric photochemical reactions. Additionally, sediments that embed ash layers either do not contain sulfate or contain minor sulfate with Δ17O near 0 permil, suggesting that the observed sulfate in ash is of volcanic origin. Mass-dependent sulfur isotopic compositions suggest that sulfate-forming reactions did not involve photolysis of SO2, unlike the situation inferred for some pre-2.3 Ga sulfates or hypothesized to occur during the formation of sulfate associated with plinian eruptions that pierce the ozone layer. However, sulfate in the products of caldera-forming eruptions display a large δ34S range and fractionation relationships that do not follow equilibrium slopes of 0.515 and 1.90 for 33S/32S vs. 34S/32S and 36S/32S vs. 34S/32S, respectively. This implies that the sulfur isotopic characteristics of these sulfates were not set by a single stage, high-temperature equilibrium process in the volcanic plum. The data presented here are consistent with a single stage kinetic fractionation of sulfur

  14. Rare sulfur and triple oxygen isotope geochemistry of volcanogenic sulfate aerosols

    NASA Astrophysics Data System (ADS)

    Bindeman, I. N.; Eiler, J. M.; Wing, B. A.; Farquhar, J.

    2007-05-01

    We present analyses of stable isotopic ratios 17O/ 16O, 18O/ 16O, 34S/ 32S, and 33S/ 32S, 36S/ 32S in sulfate leached from volcanic ash of a series of well known, large and small volcanic eruptions. We consider eruptions of Mt. St. Helens (Washington, 1980, ˜1 km 3), Mt. Spurr (Alaska, 1953, <1 km 3), Gjalp (Iceland, 1996, 1998, <1 km 3), Pinatubo (Phillipines, 1991, 10 km 3), Bishop tuff (Long Valley, California, 0.76 Ma, 750 km 3), Lower Bandelier tuff (Toledo Caldera, New Mexico, 1.61 Ma, 600 km 3), and Lava Creek and Huckleberry Ridge tuffs (Yellowstone, Wyoming, 0.64 Ma, 1000 km 3 and 2.04 Ma 2500 km 3, respectively). This list covers much of the diversity of sizes and the character of silicic volcanic eruptions. Particular emphasis is paid to the Lava Creek tuff for which we present wide geographic sample coverage. This global dataset spans a significant range in δ34S, δ18O, and Δ17O of sulfate (29‰, 30‰, and 3.3‰, respectively) with oxygen isotopes recording mass-independent ( Δ17O > 0.2‰) and sulfur isotopes exhibiting mass-dependent behavior. Products of large eruptions account for most of' these isotopic ranges. Sulfate with Δ17O > 0.2‰ is present as 1-10 μm gypsum crystals on distal ash particles and records the isotopic signature of stratospheric photochemical reactions. Sediments that embed ash layers do not contain sulfate or contain little sulfate with Δ17O near 0‰, suggesting that the observed sulfate in ash is of volcanic origin. Mass-dependent fractionation of sulfur isotopic ratios suggests that sulfate-forming reactions did not involve photolysis of SO 2, like that inferred for pre-2.3 Ga sulfates from Archean sediments or Antarctic ice-core sulfate associated with few dated eruptions. Even though the sulfate sulfur isotopic compositions reflect mass-dependent processes, the products of caldera-forming eruptions display a large δ34S range and exhibit fractionation relationships that do not follow the expected equilibrium

  15. Sulfur Isotopic Inferences of the Controls on Porewater Sulfate Profiles in the Northern Cascadia Margin Gas Hydrate System

    NASA Astrophysics Data System (ADS)

    Bui, T.; Pohlman, J.; Lapham, L.; Riedel, M.; Wing, B. A.

    2010-12-01

    The flux of methane from gas hydrate bearing seeps in the marine environment is partially mitigated by the anaerobic oxidation of methane coupled with sulfate reduction. Sedimentary porewater sulfate profiles above gas hydrate deposits are frequently used to estimate the efficacy of this important microbial biofilter. However, to differentiate how other processes (e.g., sulfate reduction coupled to organic matter oxidation, sulfide re-oxidation and sulfur disproportionation) affect sulfate profiles, a complete accounting of the sulfur cycle is necessary. To this end, we have obtained the first ever measurements of minor sulfur isotopic ratios (33S/32S, 36S/32S), in conjunction with the more commonly measured 34S -32S ratio, from porewater sulfate above a gas hydrate-bearing seep. Characteristic minor isotopic fractionations, even when major isotopic fractionations are similar in magnitude, help to quantify the contributions of different microbial processes to the overall sulfur cycling in the system. Down to sediment depths of 1.5 to 4 meters, the δ34S values of porewater sulfate generally increased in association with a decrease in sulfate concentrations as would be expected for active sulfate reduction. Of greater interest, covariance between the δ34S values and measured minor isotopic fractionation suggests sulfide reoxidation and sulfur disproportionation are important components of the local sulfur cycle. We hypothesize that sulfide reoxidation is coupled to redox processes involving Fe(III) and Mn(IV) reduction and that the reoxidized forms of sulfur are available for additional methane oxidation. Recognizing that sulfate reduction is only one of several microbial processes controlling sulfate profiles challenges current paradigms for interpreting sulfate profiles and may alter our understanding of methane oxidation at gas hydrate-bearing seeps.

  16. High-precision sulfur isotope composition of enstatite meteorites and implications of the formation and evolution of their parent bodies

    NASA Astrophysics Data System (ADS)

    Defouilloy, C.; Cartigny, P.; Assayag, N.; Moynier, F.; Barrat, J.-A.

    2016-01-01

    In order to better understand the formation and evolution of their parent bodies, the three isotope ratios of sulfur were analyzed in 33 enstatite meteorites (24 enstatite chondrites and 9 aubrites). The results show that on average all enstatite chondrite groups are enriched in the lightest isotopes compared to other chondrite groups, with means of δ34S of -0.28 ± 0.22‰ for EH3/4, -0.16 ± 0.16‰ for EH5, -0.32 ± 0.15‰ for EL3, -0.67 ± 0.16‰ for EL6 and -0.64 ± 0.00‰ for EL7 (all 1σ). Aubrites show a larger isotope variability in their composition, with a δ34S varying from -1.350‰ to +0.154‰. Contrary to previously published results, our data show a distinct composition for EL6 compared to other enstatite chondrites. This could be related to an impact-induced loss of isotopically heavy oldhamite (δ34S = by 3.62 ± 3.02‰ (1σ)) on the EL parent body. Although the bulk sulfur in both enstatite meteorites and aubrites does not show any significant Δ33S and Δ36S, the oldhamite fraction shows clear evidence of mass independent fractionation on the 36S/32S ratio (in 3 out of 9 analyzes, Δ36S up to +2.2‰), a signal that is not correlated to any 33S/32S anomaly (in 1 out of 9 analyzes, Δ33S down to -0.085‰). Though a nebular or photochemical origin cannot be ruled out, the most plausible mechanism to produce such isolated non-mass dependent 36S/32S anomalies would be a contribution of FeCl2 containing excesses of 36S due to the decay of 36Cl to the leached oldhamite fraction. Even though the sulfur isotopic composition measured in enstatite meteorites is distinct from the Bulk Silicate Earth (BSE), the isotopically lightest samples of EL6, EL7 and aubrites are approaching the isotopic composition of the BSE and enstatite meteorites remain the meteorites with the sulfur isotopic composition the closest to the terrestrial one.

  17. Effect of electron donors on the fractionation of sulfur isotopes by a marine Desulfovibrio sp.

    NASA Astrophysics Data System (ADS)

    Sim, Min Sub; Ono, Shuhei; Donovan, Katie; Templer, Stefanie P.; Bosak, Tanja

    2011-08-01

    Sulfur isotope effects produced by microbial dissimilatory sulfate reduction are used to reconstruct the coupled cycling of carbon and sulfur through geologic time, to constrain the evolution of sulfur-based metabolisms, and to track the oxygenation of Earth's surface. In this study, we investigate how the coupling of carbon and sulfur metabolisms in batch and continuous cultures of a recently isolated marine sulfate reducing bacterium DMSS-1, a Desulfovibrio sp ., influences the fractionation of sulfur isotopes. DMSS-1 grown in batch culture on seven different electron donors (ethanol, glycerol, fructose, glucose, lactate, malate and pyruvate) fractionates 34S/ 32S ratio from 6‰ to 44‰, demonstrating that the fractionations by an actively growing culture of a single incomplete oxidizing sulfate reducing microbe can span almost the entire range of previously reported values in defined cultures. The magnitude of isotope effect correlates well with cell specific sulfate reduction rates (from 0.7 to 26.1 fmol/cell/day). DMSS-1 grown on lactate in continuous culture produces a larger isotope effect (21-37‰) than the lactate-grown batch culture (6‰), indicating that the isotope effect also depends on the supply rate of the electron donor and microbial growth rate. The largest isotope effect in continuous culture is accompanied by measurable changes in cell length and cellular yield that suggest starvation. The use of multiple sulfur isotopes in the model of metabolic fluxes of sulfur shows that the loss of sulfate from the cell and the intracellular reoxidation of reduced sulfur species contribute to the increase in isotope effects in a correlated manner. Isotope fractionations produced during sulfate reduction in the pure culture of DMSS-1 expand the previously reported range of triple sulfur isotope effects ( 32S, 33S, and 34S) by marine sulfate reducing bacteria, implying that microbial sulfur disproportionation may have a smaller 33S isotopic fingerprint

  18. Sulfur isotopic analysis of carbonyl sulfide and its application for biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Hattori, Shohei; Kamezaki, Kazuki; Ogawa, Takahiro; Toyoda, Sakae; Katayama, Yoko; Yoshida, Naohiro

    2016-04-01

    Carbonyl sulfide (OCS or COS) is the most abundant gas containing sulfur in the atmosphere, with an average mixing ratio of 500 p.p.t.v. in the troposphere. OCS is suggested as a sulfur source of the stratospheric sulfate aerosols (SSA) which plays an important role in Earth's radiation budget and ozone depletion. Therefore, OCS budget should be validated for prediction of climate change, but the global OCS budget is imbalance. Recently we developed a promising new analytical method for measuring the stable sulfur isotopic compositions of OCS using nanomole level samples: the direct isotopic analytical technique of on-line gas chromatography-isotope ratio mass spectrometry (GC-IRMS) using fragmentation ions S+ (Hattori et al., 2015). The first measurement of the δ34S value for atmospheric OCS coupled with isotopic fractionation for OCS sink reactions in the stratosphere (Hattori et al., 2011; Schmidt et al., 2012; Hattori et al., 2012) explains the reported δ34S value for background stratospheric sulfate, suggesting that OCS is a potentially important source for background (nonepisodic or nonvolcanic) stratospheric sulfate aerosols. This new method measuring δ34S values of OCS can be used to investigate OCS sources and sinks in the troposphere to better understand its cycle. It is known that some microorganisms in soil can degrade OCS, but the mechanism and the contribution to the OCS in the air are still uncertain. In order to determine sulfur isotopic enrichment factor of OCS during degradation via microorganisms, incubation experiments were conducted using strains belonging to the genera Mycobacterium, Williamsia and Cupriavidus, isolated from natural soil environments (Kato et al., 2008). As a result, sulfur isotope ratios of OCS were increased during degradation of OCS, indicating that reaction for OC32S is faster than that for OC33S and OC34S. OCS degradation via microorganisms is not mass-independent fractionation (MIF) process, suggesting that this

  19. 33S NMR cryogenic probe for taurine detection

    NASA Astrophysics Data System (ADS)

    Hobo, Fumio; Takahashi, Masato; Maeda, Hideaki

    2009-03-01

    With the goal of a S33 nuclear magnetic resonance (NMR) probe applicable to in vivo NMR on taurine-biological samples, we have developed the S33 NMR cryogenic probe, which is applicable to taurine solutions. The NMR sensitivity gain relative to a conventional broadband probe is as large as 3.5. This work suggests that improvements in the preamplifier could allow NMR measurements on 100 μM taurine solutions, which is the level of sensitivity necessary for biological samples.

  20. Multi-isotope biogeochemistry of sulfur in the water column and surface sediments of the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Böttcher, M. E.; Kamyshny, A.; Dellwig, O.; Farquhar, J.

    2012-04-01

    The anoxic deeps of the modern Baltic Sea with the temporal development of a pelagic redoxcline offer the opportunity to study the fundamental processes in the sulfur cycle of natural dynamic euxinic systems. In the low-temperature sulfur cycle multi-sulfur isotope discrimination has been found to be of particular value for the evaluation of fundamental biogeochemical processes and has, therefore, reached a lot of attention within the past decade. We analyzed the concentrations and stable sulfur isotope (S-32, S-33, S-34, S-36) compositions of dissolved sulfide and sulfate, as well as elemental sulfur in the water column, and of sulfate, acid-volatile sulfide (FeS + HS-) and CrII-reducible sulfur (essentially pyrite) in surface sediments of several stations in the Landsort Deep (LD) and the Gotland Basin (GB). Samples were recovered during several research cruises to the Baltic Sea. Water column samples were obtained via the IOW pump-CTD system or a conventional CTD-rosette system; short sediment cores were retrieved with a multi coring device. Special focus was set on the zone at and below the pelagic redoxcline. Stable isotope results are compared to previous measurements of the traditional sulfur isotopes (S-32, S-34), and findings from other euxinic systems. The direct correlation between salinity and dissolved sulfate and the low concentrations of dissolved sulfide (below 40 µM in the LD and 130 µM in the GB) indicate that now significant net pelagic sulfate reduction took place. Most of the sulfide originates from microbial processes in the surface sediments and further diffusion into the water column. The magnitude of overall 34S/32S discrimination between dissolved sulfate and sulfide in the anoxic water column was 49±1 (LD) and 46±2 (GB) per mil, with only small vertical variations and significantly smaller than in the modern Black Sea. This partitioning is within the range of published results found in experiments with pure cultures of sulfate

  1. Palaeoarchean Barite Deposits in the Barberton Greenstone Belt: Origin and Links to Early Microbial Life

    NASA Astrophysics Data System (ADS)

    Mason, P. R.; Peters, A.; Nijman, W.; Reimer, T. O.; Whitehouse, M. J.

    2008-12-01

    Barite deposits are considered important for identifying microbial S cycling in Archean rocks since they can provide information about S isotopes in coexisting sulfate and sulfide minerals. However the degree to which barite and pyrite in metasedimentary rocks are related remains unclear. In this study we have investigated the origin of barite and pyrite in four main horizons seen in both outcrop and fresh drill core material from the Lower Mapepe formation (3.26 to 3.23 Ga), Barberton Greenstone Belt, South Africa. Host rocks include shales, cherts, tuffs and conglomerates that are variably silicified and/or affected by carbonate alteration. The high-energy depositional environment of the host rocks, mineralogical textures, barite chemistry and the occurrence of feldspars from the rarely-found celsian-hyalophane-orthoclase series suggest a seafloor exhalative origin for the barite. In contrast pyrite is closely associated with cherts and dolomitic units where rare earth element and Y data support a marine influence. Pyrite chemistry (Co/Ni= 0.1-1, Se/S <5 x 10- 5) also indicates a low temperature sedimentary origin. Multiple S isotope data (32S, 33S, 34S, determined by SIMS) for pyrite indicates a number of arrays with limited δ34S fractionation at constant Δ33S associated with individual syn-sedimentary microcrystalline pyrite layers. Isolated euhedral pyrites in massive chert and barite rich units show much more scatter and larger degrees of Δ33S variation (-1 to +4 ). Our results are consistent with models invoking microbial mass dependent fractionation of a heterogeneous elemental sulfur source derived from atmospheric photolysis. The sulfate reservoir can also be linked to photolysis but there is no clear relationship between the barite and pyrite S isotope data, suggesting that microbial (or abiotic) sulfate reduction was absent at this time or that the basinal sulfate concentration must have remained significantly lower than the mM level prior to barite

  2. Sulfur Isotope Effects of Dissimilatory Sulfite Reductase

    PubMed Central

    Leavitt, William D.; Bradley, Alexander S.; Santos, André A.; Pereira, Inês A. C.; Johnston, David T.

    2015-01-01

    The precise interpretation of environmental sulfur isotope records requires a quantitative understanding of the biochemical controls on sulfur isotope fractionation by the principle isotope-fractionating process within the S cycle, microbial sulfate reduction (MSR). Here we provide the only direct observation of the major (34S/32S) and minor (33S/32S, 36S/32S) sulfur isotope fractionations imparted by a central enzyme in the energy metabolism of sulfate reducers, dissimilatory sulfite reductase (DsrAB). Results from in vitro sulfite reduction experiments allow us to calculate the in vitro DsrAB isotope effect in 34S/32S (hereafter, 34εDsrAB) to be 15.3 ± 2‰, 2σ. The accompanying minor isotope effect in 33S, described as 33λDsrAB, is calculated to be 0.5150 ± 0.0012, 2σ. These observations facilitate a rigorous evaluation of the isotopic fractionation associated with the dissimilatory MSR pathway, as well as of the environmental variables that govern the overall magnitude of fractionation by natural communities of sulfate reducers. The isotope effect induced by DsrAB upon sulfite reduction is a factor of 0.3–0.6 times prior indirect estimates, which have ranged from 25 to 53‰ in 34εDsrAB. The minor isotope fractionation observed from DsrAB is consistent with a kinetic or equilibrium effect. Our in vitro constraints on the magnitude of 34εDsrAB is similar to the median value of experimental observations compiled from all known published work, where 34εr−p = 16.1‰ (r–p indicates reactant vs. product, n = 648). This value closely matches those of MSR operating at high sulfate reduction rates in both laboratory chemostat experiments (34εSO4−H2S =  17.3 ± 1.5‰, 2σ) and in modern marine sediments (34εSO4−H2S =  17.3 ± 3.8‰). Targeting the direct isotopic consequences of a specific enzymatic processes is a fundamental step toward a biochemical foundation for reinterpreting the biogeochemical and geobiological sulfur isotope records in

  3. Sulfur Isotope Effects of Dissimilatory Sulfite Reductase.

    PubMed

    Leavitt, William D; Bradley, Alexander S; Santos, André A; Pereira, Inês A C; Johnston, David T

    2015-01-01

    The precise interpretation of environmental sulfur isotope records requires a quantitative understanding of the biochemical controls on sulfur isotope fractionation by the principle isotope-fractionating process within the S cycle, microbial sulfate reduction (MSR). Here we provide the only direct observation of the major ((34)S/(32)S) and minor ((33)S/(32)S, (36)S/(32)S) sulfur isotope fractionations imparted by a central enzyme in the energy metabolism of sulfate reducers, dissimilatory sulfite reductase (DsrAB). Results from in vitro sulfite reduction experiments allow us to calculate the in vitro DsrAB isotope effect in (34)S/(32)S (hereafter, [Formula: see text]) to be 15.3 ± 2‰, 2σ. The accompanying minor isotope effect in (33)S, described as [Formula: see text], is calculated to be 0.5150 ± 0.0012, 2σ. These observations facilitate a rigorous evaluation of the isotopic fractionation associated with the dissimilatory MSR pathway, as well as of the environmental variables that govern the overall magnitude of fractionation by natural communities of sulfate reducers. The isotope effect induced by DsrAB upon sulfite reduction is a factor of 0.3-0.6 times prior indirect estimates, which have ranged from 25 to 53‰ in (34)εDsrAB. The minor isotope fractionation observed from DsrAB is consistent with a kinetic or equilibrium effect. Our in vitro constraints on the magnitude of [Formula: see text] is similar to the median value of experimental observations compiled from all known published work, where (34)ε r-p = 16.1‰ (r-p indicates reactant vs. product, n = 648). This value closely matches those of MSR operating at high sulfate reduction rates in both laboratory chemostat experiments ([Formula: see text] 17.3 ± 1.5‰, 2σ) and in modern marine sediments ([Formula: see text] 17.3 ± 3.8‰). Targeting the direct isotopic consequences of a specific enzymatic processes is a fundamental step toward a biochemical foundation for reinterpreting the

  4. Sulfur and Oxygen Isotopic Analysis of a Cosmic Symplectite from a Comet Wild 2 Stardust Terminal Particle

    NASA Technical Reports Server (NTRS)

    Nguyen, A. N.; Berger, E. L.; Nakamura-Messenger, K.; Messenger, S.

    2015-01-01

    Introduction: Analyses of comet 81P/Wild 2 samples re-turned from the Stardust mission have uncovered surprising simi-larities to meteoritic material, including the identification of inner solar system grains [1-3]. The TEM characterization of terminal particle (TP) 4 from Stardust track #147 revealed an assemblage consisting of symplectically intergrown pentlandite and nanocrys-talline maghemite coexisting with high-Ca pyroxene [4]. Mineral-ogically similar cosmic symplectites (COS) containing pentlandite and magnetite in the primitive Acfer 094 meteorite are highly de-pleted in 16O (?17O, ?18O 180 per mille) [5-7]. This isotopic signature is proposed to record alteration with primordial solar nebula water. Conversely, the normal O isotopic composition of the Stardust COS indicates alteration by a different aqueous reservoir, perhaps on the comet [8]. In this study, we analyzed the Wild 2 COS for S isotopes to further constrain its origin. Experimental: Thin sections of TP4 (12 ?m) were produced and their mineralogy was thoroughly characterized by TEM. Two of the sections were analyzed for O isotopes by isotopic imaging in the JSC NanoSIMS 50L. The sample in one of the slices was completely consumed. The remaining material in the adjacent slice was analyzed simultaneously for 16O, 32S, 33S, 34S, and 56Fe16O in electron multipliers using a Cs+ primary ion beam. Quasi-simulta-neous arrival (QSA) can have a significant effect on S isotopic ra-tios when using electron multipliers, resulting in undercounting of 32S [9]. Canyon Diablo troilite (CDT) was measured numerous times to deduce a correction factor for QSA and ensure measure-ment reproducibility. Isotopic ratios are reported relative to CDT. Results and Discussion: The Wild 2 COS is enriched in the heavy S isotopes relative to CDT (?33S = 6.5 +/- 1.6 per mille; ?34S = 5.1 +/- 0.7 per mille; 1?). The degree of 33S enrichment indicates mass-inde-pendent fractionation (MIF) with ?33S = 3.9 +/- 1.7 per mille. MIF of

  5. Multiple sulfur isotope composition of oxidized Samoan melts and the implications of a sulfur isotope 'mantle array' in chemical geodynamics

    NASA Astrophysics Data System (ADS)

    Labidi, J.; Cartigny, P.; Jackson, M. G.

    2015-05-01

    To better address how subducted protoliths drive the Earth's mantle sulfur isotope heterogeneity, we report new data for sulfur (S) and copper (Cu) abundances, S speciation and multiple S isotopic compositions (32S, 33S, 34S, 36S) in 15 fresh submarine basaltic glasses from the Samoan archipelago, which defines the enriched-mantle-2 (EM2) endmember. Bulk S abundances vary between 835 and 2279 ppm. About 17 ± 11% of sulfur is oxidized (S6+) but displays no consistent trend with bulk S abundance or any other geochemical tracer. The S isotope composition of both dissolved sulfide and sulfate yield homogeneous Δ33S and Δ36S values, within error of Canyon Diablo Troilite (CDT). In contrast, δ34S values are variable, ranging between +0.11 and +2.79‰ (±0.12‰ 1σ) for reduced sulfur, whereas oxidized sulfur values vary between +4.19 and +9.71‰ (±0.80‰, 1σ). Importantly, δ34S of the reduced S pool correlates with the 87Sr/86Sr ratios of the glasses, in a manner similar to that previously reported for South-Atlantic MORB, extending the trend to δ34S values up to + 2.79 ± 0.04 ‰, the highest value reported for undegassed oceanic basalts. As for EM-1 basalts from the South Atlantic ridge, the linear δ34S-87Sr/86Sr trend requires the EM-2 endmember to be relatively S-rich, and only sediments can account for these isotopic characteristics. While many authors argue that both the EM-1 and EM-2 mantle components record subduction of various protoliths (e.g. upper or lower continental crust, lithospheric mantle versus intra-metasomatized mantle, or others), it is proposed here that they primarily reflect sediment recycling. Their distinct Pb isotope variation can be accounted for by varying the proportion of S-poor recycled oceanic crust in the source of mantle plumes.

  6. Line Intensities of Isotopic Carbonyl Sulfide (ocs) at 2.5 Micrometer

    NASA Astrophysics Data System (ADS)

    Toth, Robert A.; Sung, Keeyoon; Brown, Linda R.; Crawford, Timothy J.

    2009-06-01

    We have measured line intensities of ^{16}O^{12}C^{32}S, ^{16}O^{13}C^{32}S, ^{16}O^{12}C^{33}S, ^{16}O^{12}C^{34}S, and ^{18}O^{12}C^{32}S in the 2.5 μm region for the first time to support planetary studies of the Venus atmosphere. Laboratory absorption spectra of OCS were recorded at 0.0033 cm^{-1} resolution at room temperature using a Bruker IFS 125-HR Fourier transform spectrometer at the Jet Propulsion Laboratory. Normal samples of OCS were used in this study, and sample impurities and isotopic abundances were determined from mass spectrum analysis. Optical densities sufficient to observe isotopic bands and weaker hot bands were achieved by using a multi-pass White cell and single pass gas cells in various path lengths, which were validated by analyzing near-IR CO_2 spectra. We present line intensities for almost 30 bands of the OCS isotopes excluding ground state bands of ^{16}O^{12}C^{32}S, which we have reported recently. We have Herman-Wallis factors determined for the individual bands. In some cases, it has been observed that band intensities normalized to 100% isotopic species show a significant deviation from that of the primary isotopic species (up to by 12.5%). No earlier measurements have been reported for these bands. Measurement precision and accuracies will be discussed. Research described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration. We thank Drs. Stojan Madzunkov, John A. MacAskill, and Murray R. Darrach from the Atomic and Molecular Collision Group at Jet Propulsion Laboratory for recording mass spectrum of the OCS sample used in this work.

  7. Multiple sulfur isotopes fractionations associated with abiotic sulfur transformations in Yellowstone National Park geothermal springs

    PubMed Central

    2014-01-01

    Background The paper presents a quantification of main (hydrogen sulfide and sulfate), as well as of intermediate sulfur species (zero-valent sulfur (ZVS), thiosulfate, sulfite, thiocyanate) in the Yellowstone National Park (YNP) hydrothermal springs and pools. We combined these measurements with the measurements of quadruple sulfur isotope composition of sulfate, hydrogen sulfide and zero-valent sulfur. The main goal of this research is to understand multiple sulfur isotope fractionation in the system, which is dominated by complex, mostly abiotic, sulfur cycling. Results Water samples from six springs and pools in the Yellowstone National Park were characterized by pH, chloride to sulfate ratios, sulfide and intermediate sulfur species concentrations. Concentrations of sulfate in pools indicate either oxidation of sulfide by mixing of deep parent water with shallow oxic water, or surface oxidation of sulfide with atmospheric oxygen. Thiosulfate concentrations are low (<6 μmol L-1) in the pools with low pH due to fast disproportionation of thiosulfate. In the pools with higher pH, the concentration of thiosulfate varies, depending on different geochemical pathways of thiosulfate formation. The δ34S values of sulfate in four systems were close to those calculated using a mixing line of the model based on dilution and boiling of a deep hot parent water body. In two pools δ34S values of sulfate varied significantly from the values calculated from this model. Sulfur isotope fractionation between ZVS and hydrogen sulfide was close to zero at pH < 4. At higher pH zero-valent sulfur is slightly heavier than hydrogen sulfide due to equilibration in the rhombic sulfur–polysulfide – hydrogen sulfide system. Triple sulfur isotope (32S, 33S, 34S) fractionation patterns in waters of hydrothermal pools are more consistent with redox processes involving intermediate sulfur species than with bacterial sulfate reduction. Small but resolved differences in ∆33S among

  8. SQUID–SIMS is a useful approach to uncover primary signals in the Archean sulfur cycle

    PubMed Central

    Fischer, Woodward W.; Fike, David A.; Johnson, Jena E.; Raub, Timothy D.; Guan, Yunbin; Kirschvink, Joseph L.; Eiler, John M.

    2014-01-01

    Many aspects of Earth’s early sulfur cycle, from the origin of mass-anomalous fractionations to the degree of biological participation, remain poorly understood—in part due to complications from postdepositional diagenetic and metamorphic processes. Using a combination of scanning high-resolution magnetic superconducting quantum interference device (SQUID) microscopy and secondary ion mass spectrometry (SIMS) of sulfur isotopes (32S, 33S, and 34S), we examined drill core samples from slope and basinal environments adjacent to a major Late Archean (∼2.6–2.5 Ga) marine carbonate platform from South Africa. Coupled with petrography, these techniques can untangle the complex history of mineralization in samples containing diverse sulfur-bearing phases. We focused on pyrite nodules, precipitated in shallow sediments. These textures record systematic spatial differences in both mass-dependent and mass-anomalous sulfur-isotopic composition over length scales of even a few hundred microns. Petrography and magnetic imaging demonstrate that mass-anomalous fractionations were acquired before burial and compaction, but also show evidence of postdepositional alteration 500 million y after deposition. Using magnetic imaging to screen for primary phases, we observed large spatial gradients in Δ33S (>4‰) in nodules, pointing to substantial environmental heterogeneity and dynamic mixing of sulfur pools on geologically rapid timescales. In other nodules, large systematic radial δ34S gradients (>20‰) were observed, from low values near their centers increasing to high values near their rims. These fractionations support hypotheses that microbial sulfate reduction was an important metabolism in organic-rich Archean environments—even in an Archean ocean basin dominated by iron chemistry. PMID:24706767

  9. SQUID-SIMS is a useful approach to uncover primary signals in the Archean sulfur cycle.

    PubMed

    Fischer, Woodward W; Fike, David A; Johnson, Jena E; Raub, Timothy D; Guan, Yunbin; Kirschvink, Joseph L; Eiler, John M

    2014-04-15

    Many aspects of Earth's early sulfur cycle, from the origin of mass-anomalous fractionations to the degree of biological participation, remain poorly understood--in part due to complications from postdepositional diagenetic and metamorphic processes. Using a combination of scanning high-resolution magnetic superconducting quantum interference device (SQUID) microscopy and secondary ion mass spectrometry (SIMS) of sulfur isotopes ((32)S, (33)S, and (34)S), we examined drill core samples from slope and basinal environments adjacent to a major Late Archean (∼2.6-2.5 Ga) marine carbonate platform from South Africa. Coupled with petrography, these techniques can untangle the complex history of mineralization in samples containing diverse sulfur-bearing phases. We focused on pyrite nodules, precipitated in shallow sediments. These textures record systematic spatial differences in both mass-dependent and mass-anomalous sulfur-isotopic composition over length scales of even a few hundred microns. Petrography and magnetic imaging demonstrate that mass-anomalous fractionations were acquired before burial and compaction, but also show evidence of postdepositional alteration 500 million y after deposition. Using magnetic imaging to screen for primary phases, we observed large spatial gradients in Δ(33)S (>4‰) in nodules, pointing to substantial environmental heterogeneity and dynamic mixing of sulfur pools on geologically rapid timescales. In other nodules, large systematic radial δ(34)S gradients (>20‰) were observed, from low values near their centers increasing to high values near their rims. These fractionations support hypotheses that microbial sulfate reduction was an important metabolism in organic-rich Archean environments--even in an Archean ocean basin dominated by iron chemistry. PMID:24706767

  10. Hydrogen Sulfide Sequestration and Storage in Geothermal System: New Mitigation Strategy to Reduce H2S from the Atmosphere and Detect its Mineralization with Multiple Sulfur Isotopic Systematics

    NASA Astrophysics Data System (ADS)

    Marieni, C.; Stefansson, A.; Gudbrandsson, S.; Gunnarsson, I.; Aradottir, E. S.; Gunnarsson Robin, J.; Ono, S.

    2015-12-01

    Hydrogen sulfide (H2S) is one of the major components in geothermal fluids and is commonly emitted into the atmosphere from geothermal power plants causing potential environmental problems. Among several mitigation methods proposed to reduce the H2S emissions, is H2S sequestration into geothermal systems. Reykjavík Energy is undertaking a pilot project at Hellisheidi geothermal system (SW Iceland) called Sulfix project where H2S is being injected into the geothermal reservoir for permanent sequestration into pyrite. The SulFix project started its operation in June 2014: the soluble geothermal gases are dissolved in geothermal waste water, and injected at 8 bars into the high temperature reservoir (>200˚C) at 750 m below the wellhead. The reactions involving sulfur in the geothermal reservoir may be traced using sulfur fluid chemistry and multiple sulfur isotope systematics (32S, 33S, 34S and 36S), including mixing between the reservoir geothermal fluid and the injection fluid, sulfide mineralization and oxidation of sulfide to sulfate. In this study we investigated the multiple sulfur isotope systematics upon sulfide mineralization under geothermal conditions. High temperature flow through experiments were carried out in basaltic glass at 200-250°C and ~5 mmol/kg H2S to study the fluid-rock interaction. The results indicate that the sulfide mineralization occurs rapidly under geothermal conditions, highlighting the leaching rate of iron from the basaltic glass as the mineralization rate determining factor. Moreover, the formation of sulfide may be traced using the δ34S33S relationship in the fluids and pyrite formation - for example to determine if non-reactive mixing between the injection fluids and reservoir fluids occurs at Hellisheidi. The experimental results have been further supported by geochemical modeling involving multiple sulfur isotope fractionation between aqueous sulfide species and rocks upon basalt dissolution and secondary pyrite formation.

  11. Sulfur and oxygen isotope studies of sulfate reduction

    NASA Astrophysics Data System (ADS)

    Farquhar, J.; Canfield, D. E.; Bao, H.; Masterson, A.; Johnston, D. T.; Wing, B. A.

    2007-12-01

    I will discuss insights into sulfur and oxygen isotope fractionations of dissimilatory sulfate reduction and specifically insight provided by experiments with natural populations of sulfate-reducing bacteria from Faellestrand, Denmark. The experiments yielded relatively large magnitude sulfur isotope fractionations for dissimilatory sulfate reduction (up to approximately 45 ‰ for 34S/32S), with higher δ18O accompanying higher δ34S, similar to that observed in previous studies. The seawater used in the experiments was spiked by addition of 17O-labelled water and the 17O content of residual sulfate was found to depend on the fraction of sulfate reduced in the experiments. The 17O data provides evidence for recycling of sulfur from metabolic intermediates and for an 18O/16O fractionation of ~25-30 ‰ for dissimilatory sulfate reduction, a magnitude that is consistent with isotopic exchange between a sulfite species and cell water. The molar ratio of oxygen exchange to sulfate reduction was found to be about 2.5. Using recent models of sulfur isotope fractionations we find that our combined sulfur and oxygen isotopic data places constraints on the proportion of sulfate recycled to the medium (78-96 %), the proportion of sulfur intermediate sulfite that was recycled by way of APS to sulfate and released back to the external sulfate pool (~70%) and also that a fraction of the sulfur intermediates between sulfite and sulfide were recycled to sulfate. These parameters can be constrained because of the independent information provided by δ18O, δ34S, 17O labels, and Δ33S.

  12. Multiple sulfur isotope fractionation and mass transfer processes during pyrite precipitation and recrystallization: An experimental study at 300 and 350 °C

    NASA Astrophysics Data System (ADS)

    Syverson, Drew D.; Ono, Shuhei; Shanks, Wayne C.; Seyfried, William E.

    2015-09-01

    Equilibrium multiple sulfur isotope fractionation factors (33S/32S and 34S/32S) between aqueous SO4, H2S, and coexisting pyrite under hydrothermal conditions were determined experimentally at 300-350 °C and 500 bars. Two different experimental techniques were used to determine the fractionation factors and the rate of S isotope exchange between pyrite and constituent aqueous species, H2S and SO4; (1) closed system gold capsule pyrite-H2S exchange experiments and (2) complimentary time-series experiments at 300 and 350 °C, 500 bars using flexible gold cell hydrothermal equipment, which allowed monitoring the multiple S isotope composition of dissolved S species during pyrite precipitation and subsequent recrystallization. The three isotope technique was applied to the multiple S isotope data to demonstrate equilibrium S isotope fractionation between pyrite and H2S. Results at 350 °C indicate ln34αPyrite/H2S = -1.9‰ and ln33αPyrite/H2S = -1.0‰. The ln34αPyrite/H2S is not only different in magnitude but also in sign from the commonly used value of 1‰ from Ohmoto and Rye (1979). This experimental study also demonstrated initial S isotope disequilibrium amongst the aqueous S-species and pyrite during rapid precipitation, despite aqueous speciation indicating pyrite saturation at all stages. Textural, crystallographic, and S isotope interpretations suggest that pyrite formed by means of the FeS pathway. The initial S isotope disequilibrium between formed pyrite and dissolved S-species was effectively erased and approached isotopic equilibrium upon recrystallization during the course of 4297 h. Interpretation of seafloor hydrothermal vent sulfides using the revised equilibrium 34S/32S fractionation between pyrite and H2S suggests that pyrite is close to S isotope equilibrium with vent H2S, contrary to previous conclusions. The experimental data reported here broaden the range of pyrite formation mechanisms at seafloor hydrothermal vents, in that mineral

  13. Isotope ratio and trace element imaging of pyrite grains in gold ores

    NASA Astrophysics Data System (ADS)

    Fleming, Ronald H.; Bekken, Barbara M.

    1995-05-01

    Secondary ion mass spectrometry techniques for imaging measurements of 34S/32S isotope ratios and quantitative trace element concentrations in pyrite mineral grains have been demonstrated. Test samples show that the 34S/32S isotope ratios are constant within Poisson error, independent of image position. Variable 34S/32S isotope ratios have been found within a a single pyrite grain in a sample of gold ore from the Carlin mine in the Carlin District of Nevada. The locations of trace gold concentrations in this ore sample correlate with relative 34S enrichment. Imaging has the inherent problem of spreading already limited minor isotope signals among many pixels. This problem can be overcome with improved analysis methodology including new electron multiplier circuitry to accommodate more intense secondary ion signals, stable data collection over relatively long time periods, and improved software. High mass resolution imaging and careful neutralization of ion beam induced sample charging are also required.

  14. Late Ordovician Seawater Sulfate δ34S in Well-preserved Brachiopods

    NASA Astrophysics Data System (ADS)

    Present, T. M.; Paris, G.; Burke, A.; Fischer, W. W.; Adkins, J. F.

    2014-12-01

    In the end-Ordovician Hirnantian stage, pyrite-sulfur and carbon isotope excursions coincide with a mass extinction and major glaciation [1]. The sulfur isotopic composition of Carbonate Associated Sulfate (δ34SCAS) is routinely measured as a proxy for the composition of ancient seawater sulfate, which offers a measure of Earth's surface redox balance during this time. However, the variance among bulk-rock CAS samples commonly greatly exceeds analytical precision. CAS analytical techniques typically require large samples (normally >30g CaCO3), so integration of different synsedimentary and diagenetic components may explain this scatter. Using a new sulfur isotope MC-ICP-MS analytical technique [2], we analyzed 5-10mg of well-preserved secondary layer fibrous calcite of brachiopod fossils collected from Late Ordovician-early Silurian sections on Anticosti Island, Canada, and compared these values to those obtained from texture-specific sampling of other carbonate phases found in these rocks. Brachiopod secondary layer calcites show a range of δ34SCAS values with only 2‰ variability—much less than the 21‰ range observed among less well-preserved and/or diagenetic components. Notably, micrite— a phase often valued for CAS analysis— is as much as 15‰ lower than brachiopods in the same hand sample. Recrystallized fossils and late diagenetic cements are enriched up to 6‰ from brachiopods. Thus, diagenetic processes can strongly impact and overprint CAS signals, even in carbonate rocks of exceptionally low thermal maturity. Our analysis of brachiopod CAS from these sections indicates that there was no marine sulfate excursion coeval with the Hirnantian carbon isotope excursion and glacial maximum. These observations support Jones and Fike's interpretation of the noisier bulk-rock δ34SCAS record from Anticosti Island [1]. In addition, we measured the sulfur isotopic composition of CAS in a modern brachiopod to confirm that it provides a robust archive of seawater sulfate. A modern Terebratalia transversa from San Pedro, CA (20.52±0.11‰, V-CDT) is very slightly depleted relative to modern seawater (20.97±0.10‰, V-CDT) [2]. We are further exploring the range of modern brachiopod CAS. [1] Jones & Fike (2013) EPSL 363, 144-155. [2] Paris et al. (2013) Chem. Geol. 345, 50-61.

  15. Experiments on δ34S mixing between organic and inorganic sulfur species during thermal maturation

    USGS Publications Warehouse

    Amrani, Alon; Said-Ahamed, Ward; Lewan, Michael D.; Aizenshtat, Zeev

    2006-01-01

    Reduced sulfur species were studied to constrain isotopic exchange-mixing with synthetic polysulfide cross-linked macromolecules (PCLM), model sulfur containing molecules and natural sulfur-rich kerogen, asphalt and oil of the Dead Sea area. PCLM represents protokerogens that are rich in sulfur and thermally unstable. Mixing rates of PCLM with HS-(aq) (added as (NH4)2S(aq)) at low to moderate temperatures (50–200 °C) are rapid. Elemental sulfur and H2S(gas) fully mix isotopes with PCLM during pyrolysis conditions at 200 °C. During these reactions significant structural changes of the PCLM occur to form polysulfide dimers, thiolanes and thiophenes. As pyrolysis temperatures or reaction times increase, the PCLM thermal products are transformed to more aromatic sulfur compounds. Isotopic mixing rates increase with increasing pyrolysis temperature and time. Polysulfide bonds (S–S) in the PCLM are responsible for most of these structural and isotopic changes because of their low stability. Conversely, sulfur isotope mixing does not occur between dibenzothiophene (aromatic S) or hexadecanthiol (C–SH) and HS-(aq) at 200 °C after 48 h. This shows that rates of sulfur isotope mixing are strongly dependent on the functionality of the sulfur in the organic matter. The order of isotopic mixing rates for organic matter is kerogen > asphalt > oil, which is inverse to their sulfur thermal stability. Asphalt and oil with more refractory sulfur show significantly lower isotopes mixing rates than the kerogen with more labile sulfur. Based on the findings of the present study we suggest that sulfur isotopes mixing can occur from early diagenesis into catagenesis and result in isotopic homogenization of the inorganic and organic reduced sulfur pools.

  16. Experiments on δ 34S mixing between organic and inorganic sulfur species during thermal maturation

    NASA Astrophysics Data System (ADS)

    Amrani, Alon; Said-Ahamed, Ward; Lewan, Michael D.; Aizenshtat, Zeev

    2006-10-01

    Reduced sulfur species were studied to constrain isotopic exchange-mixing with synthetic polysulfide cross-linked macromolecules (PCLM), model sulfur containing molecules and natural sulfur-rich kerogen, asphalt and oil of the Dead Sea area. PCLM represents protokerogens that are rich in sulfur and thermally unstable. Mixing rates of PCLM with HS-(aq) (added as (NH 4) 2S (aq)) at low to moderate temperatures (50-200 °C) are rapid. Elemental sulfur and H 2S (gas) fully mix isotopes with PCLM during pyrolysis conditions at 200 °C. During these reactions significant structural changes of the PCLM occur to form polysulfide dimers, thiolanes and thiophenes. As pyrolysis temperatures or reaction times increase, the PCLM thermal products are transformed to more aromatic sulfur compounds. Isotopic mixing rates increase with increasing pyrolysis temperature and time. Polysulfide bonds (S-S) in the PCLM are responsible for most of these structural and isotopic changes because of their low stability. Conversely, sulfur isotope mixing does not occur between dibenzothiophene (aromatic S) or hexadecanthiol (C-SH) and HS-(aq) at 200 °C after 48 h. This shows that rates of sulfur isotope mixing are strongly dependent on the functionality of the sulfur in the organic matter. The order of isotopic mixing rates for organic matter is kerogen > asphalt > oil, which is inverse to their sulfur thermal stability. Asphalt and oil with more refractory sulfur show significantly lower isotopes mixing rates than the kerogen with more labile sulfur. Based on the findings of the present study we suggest that sulfur isotopes mixing can occur from early diagenesis into catagenesis and result in isotopic homogenization of the inorganic and organic reduced sulfur pools.

  17. Thermal-neutron capture for A=26-35

    SciTech Connect

    Chunmei, Z.; Firestone, R.B.

    2001-06-01

    The prompt gamma-ray data of thermal- neutron captures fornuclear mass number A=26-35 had been evaluated and published in "ATOMICDATA AND NUCLEAR DATA TABLES, 26, 511 (1981)". Since that time themanyexperimental data of the thermal-neutron captures have been measuredand published. The update of the evaluated prompt gamma-ray data is verynecessary for use in PGAA of high-resolution analytical prompt gamma-rayspectroscopy. Besides, the evaluation is also very needed in theEvaluated Nuclear Structure Data File, ENSDF, because there are no promptgamma-ray data in ENSDF. The levels, prompt gamma-rays and decay schemesof thermal-neutron captures for nuclides (26Mg, 27Al, 28Si, 29Si, 30Si,31P, 32S, 33S, 34S, and 35Cl) with nuclear mass number A=26-35 have beenevaluated on the basis of all experimental data. The normalizationfactors, from which absolute prompt gamma-ray intensity can be obtained,and necessary comments are given in the text. The ENSDF format has beenadopted in this evaluation. The physical check (intensity balance andenergy balance) of evaluated thermal-neutron capture data has been done.The evaluated data have been put into Evaluated Nuclear Structure DataFile, ENSDF. This evaluation may be considered as an update of the promptgamma-ray from thermal-neutron capture data tables as published in"ATOMIC DATA AND NUCLEAR DATA TABLES, 26, 511 (1981)".

  18. Thermal-neutron capture for A=36-44

    SciTech Connect

    Chunmei, Z.; Firestone, R.B.

    2003-01-01

    The prompt gamma-ray data of thermal- neutron captures fornuclear mass number A=26-35 had been evaluated and published in "ATOMICDATA AND NUCLEAR DATA TABLES, 26, 511 (1981)". Since that time the manyexperimental data of the thermal-neutron captures have been measured andpublished. The update of the evaluated prompt gamma-ray data is verynecessary for use in PGAA of high-resolution analytical prompt gamma-rayspectroscopy. Besides, the evaluation is also very needed in theEvaluated Nuclear Structure Data File, ENSDF, because there are no promptgamma-ray data in ENSDF. The levels, prompt gamma-rays and decay schemesof thermal-neutron captures fornuclides (26Mg, 27Al, 28Si, 29Si, 30Si,31P, 32S, 33S, 34S, and 35Cl) with nuclear mass number A=26-35 have beenevaluated on the basis of all experimental data. The normalizationfactors, from which absolute prompt gamma-ray intensity can be obtained,and necessary comments are given in the text. The ENSDF format has beenadopted in this evaluation. The physical check (intensity balance andenergy balance) of evaluated thermal-neutron capture data has been done.The evaluated data have been put into Evaluated Nuclear Structure DataFile, ENSDF. This evaluation may be considered as an update of the promptgamma-ray from thermal-neutron capture data tables as published in"ATOMIC DATA AND NUCLEAR DATA TABLES, 26, 511 (1981)".

  19. Vibronic origin of sulfur mass-independent isotope effect in photoexcitation of SO2 and the implications to the early earth's atmosphere.

    PubMed

    Whitehill, Andrew R; Xie, Changjian; Hu, Xixi; Xie, Daiqian; Guo, Hua; Ono, Shuhei

    2013-10-29

    Signatures of mass-independent isotope fractionation (MIF) are found in the oxygen ((16)O,(17)O,(18)O) and sulfur ((32)S, (33)S, (34)S, (36)S) isotope systems and serve as important tracers of past and present atmospheric processes. These unique isotope signatures signify the breakdown of the traditional theory of isotope fractionation, but the physical chemistry of these isotope effects remains poorly understood. We report the production of large sulfur isotope MIF, with Δ(33)S up to 78‰ and Δ(36)S up to 110‰, from the broadband excitation of SO2 in the 250-350-nm absorption region. Acetylene is used to selectively trap the triplet-state SO2 ( (3)B1), which results from intersystem crossing from the excited singlet ( (1)A2/ (1)B1) states. The observed MIF signature differs considerably from that predicted by isotopologue-specific absorption cross-sections of SO2 and is insensitive to the wavelength region of excitation (above or below 300 nm), suggesting that the MIF originates not from the initial excitation of SO2 to the singlet states but from an isotope selective spin-orbit interaction between the singlet ( (1)A2/ (1)B1) and triplet ( (3)B1) manifolds. Calculations based on high-level potential energy surfaces of the multiple excited states show a considerable lifetime anomaly for (33)SO2 and (36)SO2 for the low vibrational levels of the (1)A2 state. These results demonstrate that the isotope selectivity of accidental near-resonance interactions between states is of critical importance in understanding the origin of MIF in photochemical systems. PMID:23836655

  20. The density structure of the L1157 molecular outflow

    NASA Astrophysics Data System (ADS)

    Gómez-Ruiz, A. I.; Codella, C.; Lefloch, B.; Benedettini, M.; Busquet, G.; Ceccarelli, C.; Nisini, B.; Podio, L.; Viti, S.

    2015-02-01

    We present a multiline CS survey towards the brightest bow-shock B1 in the prototypical chemically active protostellar outflow L1157. We made use of (sub-)mm data obtained in the framework of the Chemical HErschel Surveys of Star forming regions and Astrochemical Surveys at IRAM (ASAI) key science programs. We detected 12C32S, 12C34S, 13C32S, and 12C33S emissions, for a total of 18 transitions, with Eu up to ˜180 K. The unprecedented sensitivity of the survey allows us to carefully analyse the line profiles, revealing high-velocity emission, up to 20 km s-1 with respect to the systemic. The profiles can be well fitted by a combination of two exponential laws that are remarkably similar to what previously found using CO. These components have been related to the cavity walls produced by the ˜2000 yr B1 shock and the older (˜4000 yr) B2 shock, respectively. The combination of low- and high-excitation CS emission was used to properly sample the different physical components expected in a shocked region. Our CS observations show that this molecule is highlighting the dense, nH2 = 1-5 × 105 cm-3, cavity walls produced by the episodic outflow in L1157. In addition, the highest excitation (Eu ≥ 130 K) CS lines provide us with the signature of denser (1-5 × 106 cm-3) gas, associated with a molecular reformation zone of a dissociative J-type shock, which is expected to arise where the precessing jet impacting the molecular cavities. The CS fractional abundance increases up to ˜10-7 in all the kinematical components. This value is consistent with what previously found for prototypical protostars and it is in agreement with the prediction of the abundances obtained via the chemical code Astrochem.

  1. Dense cavity walls traced by CS in the L1157-B1 protostellar shocked region

    NASA Astrophysics Data System (ADS)

    Gomez-Ruiz, Arturo; Codella, Claudio; Lefloch, Bertrand; Benedettini, Milena; Busquet, Gemma; Nisini, Brunella; Ceccarelli, Cecilia; Cabrit, Sylvie; Viti, Serena

    2013-07-01

    In the framework of the CHESS Key Program, an unbiased spectral survey performed with Herschel and IRAM, in the frequency range from 97 to 600 GHz, have provided a chemical census of the protostellar shock L1157-B1. Here we focus on the study of carbon monosulfide (CS), a standard tracer of high-density gas. We have detected a total of 18 emission lines, with E_u up to 183 K, due to four isotopologues (^12C^32S, ^12C^34S, ^13C^32S, and ^12C^33S). The unprecedented sensitivity of the survey allow us to carefully analyze the line profiles. These profiles can be well fitted by two exponential laws: I ∝ exp(-|v/v0|) with v0 = 4.4, and 2.5 km s-1. Remarkably these two exponential laws are the same as those found in the CO line profiles by Lefloch et al. (2012), and named g2 and g3 components, respectively. These components have been related to the cavity walls produced by the B1 shock and the older B2 shock, respectively. An important characteristic of the lines profiles is that the emission of high-J CS transitions (E_u > 60 K) comes only from the g2 component. Using the LVG approximation, the CS solutions constrain n >= 10^4.5 cm^-3. In addition, when contrasted with the CO results (that already constrained T_k of 90 K and 40 K for g2 and g3, respectively), we see that the LVG can provide strong constrains to the gas density, in this case about 5 x 10^5 cm^-3 for both g2 and g3 components. Thus, the combination of CO and CS is a powerful tool to constrain both n and T_k. Our CS observations show therefore that this molecule is highlighting the dense cavity walls produced by the episodic outflow.

  2. Chandra discovery of 3.2s X-ray pulsations from SGR 1935+2154

    NASA Astrophysics Data System (ADS)

    Israel, Gian Luca; Rea, Nanda; Zelati, Francesco Coti; Esposito, Paolo; Burgay, Marta; Mereghetti, Sandro; Possenti, Andrea; Tiengo, Andrea

    2014-08-01

    Following the Swift-BAT detection of a short and relatively soft burst from less than 1 degree from the Galactic plane (GRB 140705A; GCN Circ. 16520, 16521, 16522 and 16530), and similar to those usually displayed by Soft Gamma-ray Repeaters, we have activated our Chandra (ID 15875; PI: Rea) ToO program.

  3. Fourier Transform Microwave Spectrum of CO{_2} -(CH{_3}){_2} S

    NASA Astrophysics Data System (ADS)

    Kawashima, Yoshiyuki; Moritani, Takayuki; Hirota, Eizi

    2012-06-01

    In spite of the fact that the oxygen and sulfur atoms belong to the same group in the periodic table, oxygen-containing molecules and their corresponding sulfur analogues often exhibit characteristic differences in their chemical and physical properties. We have been interested in these differences and have investigated, in a systematic way using Fourier transform microwave (FTMW) spectroscopy combined with ab initio molecular orbital calculations, complexes consisting of dimethyl ether (DME)/dimethyl sulfide (DMS) and ethylene oxide (EO)/ ethylene sulfide (ES), each being attached to either one of rare gas atoms (Rg), CO, N{_2}, or CO{_2}. Among others the CO{_2}-DMS complex should be mentioned, which, in sharp contrast with its counterpart: CO{_2}-DME behaves anomalously, presumably because of low-frequency internal motions, and we have decided to explore it in detail by a FTMW spectrometer. We have generated the CO{_2}-DMS complex by supersonic expansion of a CO{_2} and DMS mixture diluted with Ar, and have scanned the frequency region from 5 to 24 GHz to record the rotational spectra of the complex. We have found it difficult to fit the observed transition frequencies to the ordinary rotational Hamiltonian, but have succeeded to assign 75 transitions by sum rules among the observed transition frequencies. We are suspecting the anomalous behavior of the complex to be caused by a low-frequency torsion of the moieties. In the case of the CO{_2}-DME, the internal rotations of the two methyl groups of the DME were shown to be locked to the CO{_2} by hydrogen bonding, whereas, for the CO{_2}-DMS, we have observed internal-rotation splittings of the two methyl groups of the DMS, indicating the structure of the CO{_2}-DMS complex being considerably different from that of the CO{_2}-DME. We will report the structure at the potential minima and the internal motion of the CO{_2}-DMS, in comparison with the results predicted by quantum chemical calculations. Y. Kawashima, A. Sato, Y. Orita, and E. Hirota J. Phys. Chem. A 116, 1224 2012. J. J. Newby, R. A. Peebles, and S. A. Peebles J. Phys. Chem. A 108, 11234 2004.

  4. The v(2) and 2 v3 Bands of (SO3)-S-32-O-16, (SO3)-S-32-O-18, (SO3)-S-34-O-16 and (SO3)-S-34-O-18

    SciTech Connect

    Sharpe, Steven W.; Blake, Thomas A.; Sams, Robert L.; Maki, Arthur; Masiello, Anthony; Barber, Jeffrey B.; Vulpanovici, Nicolae; Chrysostom, Engelene; Nibler, Joseph W.; Weber, Alfons

    2003-12-01

    The fifth of a series of publications on the high resolution rotation-vibration spectra of sulfur trioxide reports the results of a systematic study of the v3(é) and 2v3(A1�+E�) infrared bands of the four symmetric top isotopomers 32S16O3, 34S16O3, 32S18O3, and 34S18O3. An internal coupling between the l = 0 and l = +2 levels of the 2v3 (A1�+E�) states was observed. This small perturbation results in a level crossing between K-l = 9 and 12, in consequence of which the band origins of the A1�, l=0 “ghost” states could be determined to a high degree of accuracy. Ground and upper state rotational as well as vibrational anharmonicity constants are reported. The constants for the center-of-mass substituted species 32S16O3 and 34S16O3 vary only slightly, as do the constants for the 32S18O3, 34S18O3 pair. The S-O bond lengths for the vibrational ground states of the species 32S16O3, 34S16O3, 32S18O3 and 34S18O3, are, respectively, 141.981992(6), 141.979412(20), 150.605240(73), and 150.602348(73) pm, where the uncertainties, given in parentheses, are two standard deviations and refer to the last digits of the associated quantity.

  5. Non-chondritic sulphur isotope composition of the terrestrial mantle.

    PubMed

    Labidi, J; Cartigny, P; Moreira, M

    2013-09-12

    Core-mantle differentiation is the largest event experienced by a growing planet during its early history. Terrestrial core segregation imprinted the residual mantle composition by scavenging siderophile (iron-loving) elements such as tungsten, cobalt and sulphur. Cosmochemical constraints suggest that about 97% of Earth's sulphur should at present reside in the core, which implies that the residual silicate mantle should exhibit fractionated (34)S/(32)S ratios according to the relevant metal-silicate partition coefficients, together with fractionated siderophile element abundances. However, Earth's mantle has long been thought to be both homogeneous and chondritic for (34)S/(32)S, similar to Canyon Diablo troilite, as it is for most siderophile elements. This belief was consistent with a mantle sulphur budget dominated by late-accreted chondritic components. Here we show that the mantle, as sampled by mid-ocean ridge basalts from the south Atlantic ridge, displays heterogeneous (34)S/(32)S ratios, directly correlated to the strontium and neodymium isotope ratios (87)Sr/(86)Sr and (143)Nd/(144)Nd. These isotope trends are compatible with binary mixing between a low-(34)S/(32)S ambient mantle and a high-(34)S/(32)S recycled component that we infer to be subducted sediments. The depleted end-member is characterized by a significantly negative δ(34)S of -1.28 ± 0.33‰ that cannot reach a chondritic value even when surface sulphur (from continents, altered oceanic crust, sediments and oceans) is added. Such a non-chondritic (34)S/(32)S ratio for the silicate Earth could be accounted for by a core-mantle differentiation record in which the core has a (34)S/(32)S ratio slightly higher than that of chondrites (δ(34)S = +0.07‰). Despite evidence for late-veneer addition of siderophile elements (and therefore sulphur) after core formation, our results imply that the mantle sulphur budget retains fingerprints of core-mantle differentiation. PMID:24005324

  6. Sulfur and oxygen isotope study of sulfate reduction in experiments with natural populations from Fællestrand, Denmark

    NASA Astrophysics Data System (ADS)

    Farquhar, James; Canfield, Don E.; Masterson, Andrew; Bao, Huiming; Johnston, David

    2008-06-01

    This study investigates the sulfur and oxygen isotope fractionations of dissimilatory sulfate reduction and works to reconcile the relationships between the oxygen and sulfur isotopic and elemental systems. We report results of experiments with natural populations of sulfate-reducing bacteria using sediment and seawater from a marine lagoon at Fællestrand on the northern shore of the island of Fyn, Denmark. The experiments yielded relatively large magnitude sulfur isotope fractionations for dissimilatory sulfate reduction (up to approximately 45‰ for 34S/32S) with higher δ18O accompanying higher δ34S, similar to that observed in previous studies. The seawater used in the experiments was spiked by addition of 17O-labeled water and the 17O content of residual sulfate was found to depend on the fraction of sulfate reduced in the experiments. The 17O data provides evidence for recycling of sulfur from metabolic intermediates and for an 18O/16O fractionation of ∼25-30‰ for dissimilatory sulfate reduction. The close correlation between the 17O data and the sulfur isotope data suggests that isotopic exchange between cell water and external water (reactor water) was rapid under experimental conditions. The molar ratio of oxygen exchange to sulfate reduction was found to be about 2.5. This value is slightly lower than observed in studies of natural ecosystems [e.g., Wortmann U. G., Chernyavsky B., Bernasconi S. M., Brunner B., Böttcher M. E. and Swart P. K. (2007) Oxygen isotope biogeochemistry of pore water sulfate in the deep biosphere: dominance of isotope exchange reactions with ambient water during microbial sulfate reduction (ODP Site 1130). Geochim. Cosmochim. Acta71, 4221-4232]. Using recent models of sulfur isotope fractionations we find that our combined sulfur and oxygen isotopic data places constraints on the proportion of sulfate recycled to the medium (78-96%), the proportion of sulfur intermediate sulfite that was recycled by way of APS to sulfate

  7. High-Precision Stable Isotope Analyses with the NanoSIMS 50L (Invited)

    NASA Astrophysics Data System (ADS)

    Hauri, E. H.; Wang, J.; Papineau, D.; Hillion, F.

    2009-12-01

    The in situ measurement of isotope ratios at high precision has always been a goal of secondary ion mass spectrometery (SIMS). The NanoSIMS 50L is a third-generation ion microprobe developed by Cameca and modified in collaboration with the Carnegie Institution of Washington. This instrument encorporates a number of design and functional improvements over the stock NS50, including precise stepper motor control over all slits, apertures and stage movements, a larger magnet, and a modified multicollector (6 moveable and 1 fixed) capable of holding both Faraday cups and miniature multi-dynode electron multipliers. The instrument is capable of attaining a minimum beam diameter of <50 nanometers with Cs and <200 nanometers with oxygen, a factor of 5-10 improvement over the IMS6F/7F/1280 generation of instruments. The CIW instrument is also the first NanoSIMS to be fitted with multiple Faradays and associated high-precision electrometers. Most tests to date have been performed on conductive Fe-bearing sulfides mouted in indium and polished with near-zero relief. With Cs, a routine primary beam diameter of 100 nm is obtained with 1-2pA of current, sufficient to yield 1MHz of 32S from pyrite at >6000 MRP. A 2.5 nA Cs beam with a diameter of 700 nm yields 90 pA of 32S from pyrite at >6000 MRP, sufficient to analyze 32S-33S-34S on Faraday cups and 36S in EM @ >10,000 cps. Specification tests immediately after installation in 2005 demonstrated a reproducibility of <0.3‰ (1σ) in 10 analyses within a single sputter crater on Balmat pyrite, and this was subsequently improved to 0.15‰ (1σ) in 2006. Further tests showed that reproducibility on separate craters of a single grain, and separate craters in separate Balmat pyrite grains located in different holes of the sample holder, were improved to better than 0.2‰ (1σ) through careful attention to reproducibility of sample height (Z-axis control) and centering of the secondary ion beam in the entrance slit of the mass

  8. Sulfur isotope homogeneity of oceanic DMSP and DMS

    PubMed Central

    Amrani, Alon; Said-Ahmad, Ward; Shaked, Yeala; Kiene, Ronald P.

    2013-01-01

    Oceanic emissions of volatile dimethyl sulfide (DMS) represent the largest natural source of biogenic sulfur to the global atmosphere, where it mediates aerosol dynamics. To constrain the contribution of oceanic DMS to aerosols we established the sulfur isotope ratios (34S/32S ratio, δ34S) of DMS and its precursor, dimethylsulfoniopropionate (DMSP), in a range of marine environments. In view of the low oceanic concentrations of DMS/P, we applied a unique method for the analysis of δ34S at the picomole level in individual compounds. Surface water DMSP collected from six different ocean provinces revealed a remarkable consistency in δ34S values ranging between +18.9 and +20.3‰. Sulfur isotope composition of DMS analyzed in freshly collected seawater was similar to δ34S of DMSP, showing that the in situ fractionation between these species is small (<+1‰). Based on volatilization experiments, emission of DMS to the atmosphere results in a relatively small fractionation (−0.5 ± 0.2‰) compared with the seawater DMS pool. Because δ34S values of oceanic DMS closely reflect that of DMSP, we conclude that the homogenous δ34S of DMSP at the ocean surface represents the δ34S of DMS emitted to the atmosphere, within +1‰. The δ34S of oceanic DMS flux to the atmosphere is thus relatively constant and distinct from anthropogenic sources of atmospheric sulfate, thereby enabling estimation of the DMS contribution to aerosols. PMID:24167289

  9. Mass Independent Fractionation of Sulphur Isotopes in Precambrian Sedimentary Rocks: Indicator for Changes in Atmospheric Composition and the Operation of the Global Sulphur Cycle

    NASA Astrophysics Data System (ADS)

    Peters, M.; Farquhar, J.; Strauss, H.

    2005-12-01

    Large mass independent fractionation (MIF) of sulphur isotopes in sedimentary rocks older than 2.3 Ga and the absence of this isotopic anomaly in younger rocks seem to be the consequence of a change in Earth's atmospheric composition from essentially oxygen-free or to oxygen-rich conditions. MIF is produced by photochemical reactions of volcanogenic sulphur dioxide with UV radiation in the absence of an ozone shield. The products of such processes are elemental sulphur with positive and sulphate with negative Δ33S values. Here we present isotope data (32S, 33S, 34S) for sedimentary pyrites from Archaean and Palaeoproterozoic rocks of the Kaapvaal Craton (South Africa), the Pilbara Craton (Australia) and the Greenland Shield (Isua Supercrustal Belt). Their ages range from 3.85 to 2.47 Ga. Large positive Δ33S values up to +9.13 ‰ in several Archaean units from the Kapvaal and Pilbara Cratons are attributed to low atmospheric oxygen at that time. Interestingly, very low Δ33S values between -0.28 and +0.57 ‰ appear to characterize the Witwatersrand succession of South Africa (3.0 Ga). This rather small MIF signature was previously detected in rocks of the same age in Western Australia (OHMOTO et al., 2005). The signature is interpreted as a global signal, which could be the consequence of a shielding effect induced by one or more atmospheric components. The most probable chemical compounds for this process are methane and carbon dioxide. Rocks of the Kameeldoorns Fm. (2.71 Ga), Kaapvaal Craton, display also low values between -0.46 and +0.33 ‰, which are consistent with the small (absent) MIF signal in rocks of the Hardey Fm. (2.76 Ga) of Western Australia (OHMOTO et al., 2005). Very low carbon isotope values between -51 and -40 ‰ in late Archaean kerogens (2.6 - 2.8 Ga) indicate a high concentration of methane in the atmosphere (PAVLOV et al., 2001). This high methane level could produce an organic haze, which absorbed most of the UV radiation and prevented

  10. Sulfur in presolar silicon carbide grains from asymptotic giant branch stars

    NASA Astrophysics Data System (ADS)

    Hoppe, Peter; Lodders, Katharina; Fujiya, Wataru

    2015-06-01

    We studied 14 presolar SiC mainstream grains for C-, Si-, and S-isotopic compositions and S elemental abundances. Ten grains have low levels of S contamination and CI chondrite-normalized S/Si ratios between 2 × 10-5 and 2 × 10-4. All grains have S-isotopic compositions compatible within 2σ of solar values. Their mean S isotope composition deviates from solar by at most a few percent, and is consistent with values observed for the carbon star IRC+10216, believed to be a representative source star of the grains, and the interstellar medium. The isotopic data are also consistent with stellar model predictions of low-mass asymptotic giant branch (AGB) stars. In a δ33S versus δ34S plot the data fit along a line with a slope of 1.8 ± 0.7, suggesting imprints from galactic chemical evolution. The observed S abundances are lower than expected from equilibrium condensation of CaS in solid solution with SiC under pressure and temperature conditions inferred from the abundances of more refractory elements in SiC. Calcium to S abundance ratios are generally above unity, contrary to expectations for stoichiometric CaS solution in the grains, possibly due to condensation of CaC2 into SiC. We observed a correlation between Mg and S abundances suggesting solid solution of MgS in SiC. The low abundances of S in mainstream grains support the view that the significantly higher abundances of excess 32S found in some Type AB SiC grains are the result of in situ decay of radioactive 32Si from born-again AGB stars that condensed into AB grains.

  11. A Detailed Record of Archean Biogochemical Cycles and Seawater Chemistry Preserved in Black Shales of the Abitibi Greenstone Belt

    NASA Astrophysics Data System (ADS)

    Scott, C.; Planavsky, N. J.; Bates, S. M.; Wing, B. A.; Lyons, T. W.

    2011-12-01

    Geological and biological evolution are intimately linked within the Earth System through the medium of seawater. Thus, in order to track the co-evolution of Life and Earth during the Archean Eon we must determine how biogeochemical cycles responded to and initiated changes in the composition of Archean seawater. Among our best records of biogeochemical cycles and seawater chemistry are organic carbon-rich black shales. Here we present a detailed multi-proxy study of 2.7 Ga black shales from the Abitibi Greenstone Belt, Canada. Abitibi shales demonstrate extreme enrichments in total organic carbon (up to 15 wt. %) and total sulfur (up to 6 wt. %) reflecting vigorous biogeochemical cycling in the basin, likely driven by cyanobacteria. The speciation of reactive Fe minerals indicates that pyrite formed in a sulfidic water column (euxinia) and that dissolved Fe was the limiting reactant. The deposition of more than 50 m of euxinic black shales suggests that the Fe-rich conditions reflected by Archean BIF deposition were not necessarily ubiquitous. Biologically significant trace metals fall into two categories. Metals that can be delivered to seawater in large quantities from hydrothermal sources (e.g., Cu and Zn) are enriched in the shales, reflecting their relative abundance in seawater. Conversely, metals that are primarily delivered to the ocean during oxidative weathering of the continents (e. g., Mo and V) are largely absent from the shales, reflecting depleted seawater inventories. Thus, trace metal supply at 2.7 Ga was still dominated by geological processes. Biological forcing of trace metal inventories, through oxidative weathering of the continents, was not initiated until 2.5 Ga, when Mo enrichments are first observed in the Mt. McRae Shale, Hamersley Basin. Multiple sulfur isotope analysis (32S, 33S, 34S) of disseminated pyrite displays large mass independent fractionations (Δ33S up to 6 %) reflecting a sulfur cycle dominated by atmospheric processes

  12. Herschel Observations of EXtra-Ordinary Sources: H2S as a Probe of Dense Gas and Possibly Hidden Luminosity Toward the Orion KL Hot Core

    NASA Astrophysics Data System (ADS)

    Crockett, N. R.; Bergin, E. A.; Neill, J. L.; Black, J. H.; Blake, G. A.; Kleshcheva, M.

    2014-02-01

    We present Herschel/HIFI observations of the light hydride H2S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the Herschel Observations of EXtra-Ordinary Sources GT (guaranteed time) key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H2 32S, H2 34S, and H2 33S, respectively. We only analyze emission from the so-called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H2S follow straight lines given the uncertainties and yield T rot = 141 ± 12 K. This indicates H2S is in local thermodynamic equilibrium and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (E up >~ 1000 K) are likely populated primarily by radiation pumping. We derive a column density, N tot(H2 32S) = 9.5 ± 1.9 × 1017 cm-2, gas kinetic temperature, T kin = 120+/- ^{13}_{10} K, and constrain the H2 volume density, n_H_2 >~ 9 × 10 7 cm-3, for the H2S emitting gas. These results point to an H2S origin in markedly dense, heavily embedded gas, possibly in close proximity to a hidden self-luminous source (or sources), which are conceivably responsible for Orion KL's high luminosity. We also derive an H2S ortho/para ratio of 1.7 ± 0.8 and set an upper limit for HDS/H2S of <4.9 × 10 -3. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  13. Herschel observations of extra-ordinary sources: H{sub 2}S as a probe of dense gas and possibly hidden luminosity toward the Orion KL hot core

    SciTech Connect

    Crockett, N. R.; Bergin, E. A.; Neill, J. L.; Black, J. H.; Blake, G. A.; Kleshcheva, M.

    2014-02-01

    We present Herschel/HIFI observations of the light hydride H{sub 2}S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the Herschel Observations of EXtra-Ordinary Sources GT (guaranteed time) key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H{sub 2} {sup 32}S, H{sub 2} {sup 34}S, and H{sub 2} {sup 33}S, respectively. We only analyze emission from the so-called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H{sub 2}S follow straight lines given the uncertainties and yield T {sub rot} = 141 ± 12 K. This indicates H{sub 2}S is in local thermodynamic equilibrium and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (E {sub up} ≳ 1000 K) are likely populated primarily by radiation pumping. We derive a column density, N {sub tot}(H{sub 2} {sup 32}S) = 9.5 ± 1.9 × 10{sup 17} cm{sup –2}, gas kinetic temperature, T {sub kin} = 120±{sub 10}{sup 13} K, and constrain the H{sub 2} volume density, n{sub H{sub 2}} ≳ 9 × 10 {sup 7} cm{sup –3}, for the H{sub 2}S emitting gas. These results point to an H{sub 2}S origin in markedly dense, heavily embedded gas, possibly in close proximity to a hidden self-luminous source (or sources), which are conceivably responsible for Orion KL's high luminosity. We also derive an H{sub 2}S ortho/para ratio of 1.7 ± 0.8 and set an upper limit for HDS/H{sub 2}S of <4.9 × 10 {sup –3}.

  14. Transverse energy scaling and energy density estimates from sup 16 O- and sup 32 S-induced reactions

    SciTech Connect

    Not Available

    1989-01-01

    We discuss the dependence of transverse energy production on projectile mass, target mass, and on the impact parameter of the heavy ion reaction. The transverse energy is shown to scale with the number of participating nucleons. Various methods to estimate the attained energy density from the observed transverse energy are discussed. It is shown that the systematics of the energy density estimates suggest averages of 2--3 GeV/fm{sup 3} rather than the much higher values attained by assuming Landau-stopping initial conditions. Based on the observed scaling of the transverse energy, an initial energy density profile may be estimated. 14 refs., 4 figs.

  15. Transverse energy scaling and energy density estimates from /sup 16/O- and /sup 32/S-induced reactions

    SciTech Connect

    Awes, T.C.; Albrecht, R.; Baktash, C.; Beckmann, P.; Berger, F.; Bock, R.; Claesson, G.; Clewing, G.; Dragon, L.; Eklund, A.

    1989-01-01

    We discuss the dependence of transverse energy production on projectile mass, target mass, and on the impact parameter of the heavy ion reaction. The transverse energy is shown to scale with the number of participating nucleons. Various methods to estimate the attained energy density from the observed transverse energy are discussed. It is shown that the systematics of the energy density estimates suggest average of 2-3 GeV/fm/sup 3/ rather than the much higher values attained by assuming Landau-stopping initial conditions. Based on the observed scaling of the transverse energy, an initial energy density profile may be estimated. 11 refs., 4 figs.

  16. High resolution analysis of 32S18O2 spectra: The ν1 and ν3 interacting bands

    NASA Astrophysics Data System (ADS)

    Ulenikov, O. N.; Bekhtereva, E. S.; Krivchikova, Yu. V.; Morzhikova, Yu. B.; Buttersack, T.; Sydow, C.; Bauerecker, S.

    2015-11-01

    Highly accurate, ~(1 - 2) ×10-4cm-1, ro-vibrational spectrum of S18O2 was recorded with Bruker IFS 120 HR Fourier transform interferometer in the region of 1050-1400 cm-1 where the bands ν1 and ν3 are located. About 1560 and 1840 transitions were assigned in the experimental spectrum with the maximum values of quantum numbers Jmax. /Kamax. equal to 65/22 and 58/16 to the bands ν3 and ν1, respectively. The further weighted fit of experimentally assigned transitions was made with the Hamiltonian model which takes into account Coriolis resonance interaction between the vibrational states (100) and (001). To make the ro-vibrational analysis physically more suitable, the initial values of main spectroscopic parameters have been estimated from the values of corresponding parameters of the S16O2 species on the basis of the results of the Isotopic Substitution theory. Finally, the set of 23 spectroscopic parameters obtained from the fit reproduces values of 1292 initial "experimental" ro-vibrational energy levels (about 3400 transitions assigned in the experimental spectrum) with the drms = 0.00015cm-1. Also, the ground state parameters of the S18O2 molecule were improved.

  17. Multiple sulfur isotopes in Paleoarchean barites identify an important role for microbial sulfate reduction in the early marine environment

    NASA Astrophysics Data System (ADS)

    Roerdink, Desiree L.; Mason, Paul R. D.; Farquhar, James; Reimer, Thomas

    2012-05-01

    Bedded barites from the Barberton greenstone belt (South Africa and Swaziland) preserve a comprehensive record of atmospheric, oceanic and microbial processes involved in the formation and evolution of the Paleoarchean (3.6-3.2 Ga) oceanic sulfate reservoir. Here, we report multiple sulfur isotopic compositions from four of these barite occurrences. Relatively constant mass-independent signatures (Δ36S/Δ33S = - 1.0 ± 0.2) within deposits support an important role for atmospheric photolysis in the production of oxidized sulfur, whereas 34S enrichments relative to the inferred composition of photolytic sulfate suggest drawdown of 34S by microbial sulfate reduction. Strong compositional overlap with barites from India and Western Australia indicates the presence of a large-scale and well-mixed marine sulfate pool. Covariation between δ34S and Δ33S within individual deposits also suggests a role for processes occurring in semi-closed basins fed by this global reservoir. Based on modeling results, we interpret variations in δ34S by local microbial sulfate reduction and correlations with Δ33S by weak inputs of sulfur from magmatic sources, microbial sulfide oxidation or sulfur disproportionation. This agrees with the early occurrence of sulfate reducers in the geological record as inferred from published microscopic pyrite data, and identifies their role as important in both global oceans and local basins in the Paleoarchean.

  18. Sulfur Isotope Trends in Archean Microbialite Facies Record Early Oxygen Production and Consumption

    NASA Astrophysics Data System (ADS)

    Zerkle, A.; Meyer, N.; Izon, G.; Poulton, S.; Farquhar, J.; Claire, M.

    2014-12-01

    The major and minor sulfur isotope composition (δ34S and Δ33S) of pyrites preserved in ~2.65-2.5 billion-year-old (Ga) microbialites record localized oxygen production and consumption near the mat surface. These trends are preserved in two separate drill cores (GKF01 and BH1-Sacha) transecting the Campbellrand-Malmani carbonate platform (Ghaap Group, Transvaal Supergroup, South Africa; Zerkle et al., 2012; Izon et al., in review). Microbialite pyrites possess positive Δ33S values, plotting parallel to typical Archean trends (with a Δ33S34S slope of ~0.9) but enriched in 34S by ~3 to 7‰. We propose that these 34S-enriched pyrites were formed from a residual pool of sulfide that was partially oxidized via molecular oxygen produced by surface mat-dwelling cyanobacteria. Sulfide, carrying the range of Archean Δ33S values, could have been produced deeper within the microbial mat by the reduction of sulfate and elemental sulfur, then fractionated upon reaction with O2 produced by oxygenic photosynthesis. Preservation of this positive 34S offset requires that: 1) sulfide was only partially (50­­-80%) consumed by oxidation, meaning H2S was locally more abundant (or more rapidly produced) than O2, and 2) the majority of the sulfate produced via oxidation was not immediately reduced to sulfide, implying either that the sulfate pool was much larger than the sulfide pool, or that the sulfate formed near the mat surface was transported and reduced in another part of the system. Contrastingly, older microbialite facies (> 2.7 Ga; Thomazo et al., 2013) appear to lack these observed 34S enrichments. Consequently, the onset of 34S enrichments could mark a shift in mat ecology, from communities dominated by anoxygenic photosynthesizers to cyanobacteria. Here, we test these hypotheses with new spatially resolved mm-scale trends in sulfur isotope measurements from pyritized stromatolites of the Vryburg Formation, sampled in the lower part of the BH1-Sacha core. Millimeter

  19. Organosulfur Compounds: Molecular and Isotopic Evolution from Biota to Oil and Gas

    NASA Astrophysics Data System (ADS)

    Amrani, Alon

    2014-05-01

    Organosulfur compounds (OSCs) play important roles in the formation, preservation, and thermal degradation of sedimentary organic matter and the associated petroleum generation. Improved analytical techniques for S isotope analysis have recently enhanced our understanding of the mechanisms for OSC formation and maturation and their associated S isotope distributions. The close interaction of OSCs with inorganic S species throughout their formation and maturation affects their 34S/32S isotopic ratio (δ34S), forming specific signatures for distinct sources and processes. Ultimately, thermal maturation homogenizes the δ34S values of different fractions and individual compounds. Reservoir processes such as thermochemical sulfate reduction (TSR) introduce exogenous and isotopically distinct S into hydrocarbons and can significantly change the δ34S of petroleum or kerogen. Specific OSCs react at different rates and thus can be used to evaluate the extent of processes such as TSR. This article reviews factors that affect the 34S/32S isotopic distribution of OSCs along pathways of formation, diagenesis, and thermal alteration.

  20. An update on the Thermal Gradient Induced Non -Mass-Dependent Isotope Fractionation

    NASA Astrophysics Data System (ADS)

    Sun, T.; Niles, P. B.; Bao, H.; Socki, R. A.

    2012-12-01

    Mass flow and compositional gradient (elemental and isotope separation) occur when fluid(s) or gas(es) in an enclosure is subjected to a thermal gradient, and the phenomenon is named thermal diffusion. Gas phase thermal diffusion has been experimentally and theoretically investigated for more than a century, although there has not been a satisfactory theory to date. Nevertheless, theories predict that when dealing with a multi-isotope system, such as O16-O17-O18, S32-S33-S34-S36, or Ne20-Ne21-Ne22, the mass difference is the only term in the thermal diffusion separation factors that distinguish one isotope pair from another. Thus a mass dependent relationship is expected. For O-bearing molecules the α17O/ α 18O is expected to be at 0.5 to 0.515, and for S-bearing molecules the α33S/ α 34S at 0.5 to 0.508, where α is isotope fractionation factor between cold and warm reservoirs. We recently reported that thermal diffusion generates non-mass dependent (NMD) isotope fractionation for low-pressure O2 and SF6 gases. The observed NMD phenomenon in the simple thermal-diffusion experiments demands quantitative validation and theoretical explanation. It was suggested that additional (not mass related) terms need to be theoretically considered in the order to account for the observations. In addition to the pressure and temperature dependency illustrated in our earlier report, the role of turbulence, batch gas effects, and whether it is only a transient, non-equilibrium effect have been examined in this study. We report here new results on low-pressure O2 gas thermal diffusion. (1) In a purely diffusive vertical two-bulb setting with colder reservoir at lower position, time course experiments showed that the NMD effect persists after the system reaches isotopic steady state between warmer and colder compartments, suggesting that the effect is not a transient one. (2) When the average temperature approaching condensation point for O2, the 17O switches to migrating

  1. Exploring the in vitro formation of trimethylarsine sulfide from dimethylthioarsinic acid in anaerobic microflora of mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS

    SciTech Connect

    Kubachka, Kevin M.; Kohan, Michael C.; Herbin-Davis, Karen; Creed, John T. Thomas, David J.

    2009-09-01

    Although metabolism of arsenicals to form methylated oxoarsenical species has been extensively studied, less is known about the formation of thiolated arsenical species that have recently been detected as urinary metabolites. Indeed, their presence suggests that the metabolism of ingested arsenic is more complex than previously thought. Recent reports have shown that thiolated arsenicals can be produced by the anaerobic microflora of the mouse cecum, suggesting that metabolism prior to systemic absorption may be a significant determinant of the pattern and extent of exposure to various arsenic-containing species. Here, we examined the metabolism of {sup 34}S labeled dimethylthioarsinic acid ({sup 34}S-DMTA{sup V}) by the anaerobic microflora of the mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS/MS to monitor for the presence of various oxo- and thioarsenicals. The use of isotopically enriched {sup 34}S-DMTA{sup V} made it possible to differentiate among potential metabolic pathways for production of the trimethylarsine sulfide (TMAS{sup V}). Upon in vitro incubation in an assay containing anaerobic microflora of mouse cecum, {sup 34}S-DMTA{sup V} underwent several transformations. Labile {sup 34}S was exchanged with more abundant {sup 32}S to produce {sup 32}S-DMTA{sup V}, a thiol group was added to yield DMDTA{sup V}, and a methyl group was added to yield {sup 34}S-TMAS{sup V}. Because incubation of {sup 34}S-DMTA{sup V} resulted in the formation of {sup 34}S-TMAS{sup V}, the pathway for its formation must preserve the arsenic-sulfur bond. The alternative metabolic pathway postulated for formation of TMAS{sup V} from dimethylarsinic acid (DMA{sup V}) would proceed via a dimethylarsinous acid (DMA{sup III}) intermediate and would necessitate the loss of {sup 34}S label. Structural confirmation of the metabolic product was achieved using HPLC-ESI-MS/MS. The data presented support the direct methylation of DMTA{sup V} to TMAS{sup V}. Additionally, the detection of

  2. Sulfur sources of sedimentary "buckshot" pyrite in the Auriferous Conglomerates of the Mesoarchean Witwatersrand and Ventersdorp Supergroups, Kaapvaal Craton, South Africa

    NASA Astrophysics Data System (ADS)

    Guy, B. M.; Ono, S.; Gutzmer, J.; Lin, Y.; Beukes, N. J.

    2014-08-01

    Large rounded pyrite grains (>1 mm), commonly referred to as "buckshot" pyrite grains, are a characteristic feature of the auriferous conglomerates (reefs) in the Witwatersrand and Ventersdorp supergroups, Kaapvaal Craton, South Africa. Detailed petrographic analyses of the reefs indicated that the vast majority of the buckshot pyrite grains are of reworked sedimentary origin, i.e., that the pyrite grains originally formed in the sedimentary environment during sedimentation and diagenesis. Forty-one of these reworked sedimentary pyrite grains from the Main, Vaal, Basal, Kalkoenkrans, Beatrix, and Ventersdorp Contact reefs were analyzed for their multiple sulfur isotope compositions (δ34S, Δ33S, and Δ36S) to determine the source of the pyrite sulfur. In addition, five epigenetic pyrite samples (pyrite formed after sedimentation and lithification) from the Middelvlei and the Ventersdorp Contact reefs were measured for comparison. The δ34S, Δ33S, and Δ36S values of all 41 reworked sedimentary pyrite grains indicate clear signatures of mass-dependent and mass-independent fractionation and range from -6.8 to +13.8 ‰, -1.7 to +1.7 ‰, and -3.9 to +0.9 ‰, respectively. In contrast, the five epigenetic pyrite samples display a very limited range of δ34S, Δ33S, and Δ36S values (+0.7 to +4.0 ‰, -0.3 to +0.0 ‰. and -0.3 to +0.1 ‰, respectively). Despite the clear signatures of mass-independent sulfur isotope fractionation, very few data points plot along the primary Archean photochemical array suggesting a weak photolytic control over the data set. Instead, other factors command a greater degree of influence such as pyrite paragenesis, the prevailing depositional environment, and non-photolytic sulfur sources. In relation to pyrite paragenesis, reworked syngenetic sedimentary pyrite grains (pyrite originally precipitated along the sediment-water interface) are characterized by negative δ34S and Δ33S values, suggesting open system conditions with respect

  3. Multiple sulphur and oxygen isotopes reveal microbial sulphur cycling in spring waters in the Lower Engadin, Switzerland.

    PubMed

    Strauss, Harald; Chmiel, Hannah; Christ, Andreas; Fugmann, Artur; Hanselmann, Kurt; Kappler, Andreas; Königer, Paul; Lutter, Andreas; Siedenberg, Katharina; Teichert, Barbara M A

    2016-01-01

    Highly mineralized springs in the Scuol-Tarasp area of the Lower Engadin and in the Albula Valley near Alvaneu, Switzerland, display distinct differences with respect to the source and fate of their dissolved sulphur species. High sulphate concentrations and positive sulphur (δ(34)S) and oxygen (δ(18)O) isotopic compositions argue for the subsurface dissolution of Mesozoic evaporitic sulphate. In contrast, low sulphate concentrations and less positive or even negative δ(34)S and δ(18)O values indicate a substantial contribution of sulphate sulphur from the oxidation of sulphides in the crystalline basement rocks or the Jurassic sedimentary cover rocks. Furthermore, multiple sulphur (δ(34)S, Δ(33)S) isotopes support the identification of microbial sulphate reduction and sulphide oxidation in the subsurface, the latter is also evident through the presence of thick aggregates of sulphide-oxidizing Thiothrix bacteria. PMID:25922968

  4. USE OF SLACK-WATER ENVIRONMENTS BY COHO SALMON JUVENILES IN A COASTAL OREGON STREAM AS INDICATED BY 34S STABLE ISOTOPE ANALYSIS

    EPA Science Inventory

    Stable isotopes of sulfur are rarely used in studies of elemental cycling, trophic position or use of marine-derived nutrients by salmonids. The main reason for this probably is the reluctance on the part of isotope labs to expose their instruments to SO2 (because of its corrosi...

  5. Stable sulfur and nitrogen isotopic compositions of crude oil fractions from Southern Germany

    NASA Astrophysics Data System (ADS)

    Hirner, A. V.; Graf, W.; Treibs, R.; Melzer, A. N.; Hahn-Weinheimer, P.

    1984-11-01

    Eleven samples of crude oil from the Molasse Basin of Southern Germany were fractionated and their contents of sulfur and nitrogen as well as the stable isotope compositions of these elements ( 34S /32S and 15N /14N , resp.) investigated. According to the δ34S determinations, all crude oils from the Tertiary base of the Western and Eastern Molasse belong to one oil family and differ significantly from the Triassic and Liassic oils in the Western Molasse. An enrichment of 34S was observed with increasing polarity of crude oil fractions. The isotope distributions of sulfur in the polar constituents of the biodegraded oils from the sandstones of Ampfing, however, approach a homogeneous distribution. The nitrogen isotope distribution is rather uniform in Southern German oils. A regional differentiation can be recognized, although the overall isotopic variation is small. The δ15N values of the crudes and asphaltenes do not correlate.

  6. Mass Dependency of Isotope Fractionation of Gases Under Thermal Gradient and Its Possible Implications for Planetary Atmosphere Escaping Process

    NASA Technical Reports Server (NTRS)

    Sun, Tao; Niles, Paul; Bao, Huiming; Socki, Richard

    2014-01-01

    Physical processes that unmix elements/isotopes of gas molecules involve phase changes, diffusion (chemical or thermal), effusion and gravitational settling. Some of those play significant roles for the evolution of chemical and isotopic compositions of gases in planetary bodies which lead to better understanding of surface paleoclimatic conditions, e.g. gas bubbles in Antarctic ice, and planetary evolution, e.g. the solar-wind erosion induced gas escaping from exosphere on terrestrial planets.. A mass dependent relationship is always expected for the kinetic isotope fractionations during these simple physical processes, according to the kinetic theory of gases by Chapman, Enskog and others [3-5]. For O-bearing (O16, -O17, -O18) molecules the alpha O-17/ alpha O-18 is expected at 0.5 to 0.515, and for S-bearing (S32,-S33. -S34, -S36) molecules, the alpha S-33/ alpha S-34 is expected at 0.5 to 0.508, where alpha is the isotope fractionation factor associated with unmixing processes. Thus, one isotope pair is generally proxied to yield all the information for the physical history of the gases. However, we recently] reported the violation of mass law for isotope fractionation among isotope pairs of multiple isotope system during gas diffusion or convection under thermal gradient (Thermal Gradient Induced Non-Mass Dependent effect, TGI-NMD). The mechanism(s) that is responsible to such striking observation remains unanswered. In our past studies, we investigated polyatomic molecules, O2 and SF6, and we suggested that nuclear spin effect could be responsible to the observed NMD effect in a way of changing diffusion coefficients of certain molecules, owing to the fact of negligible delta S-36 anomaly for SF6.. On the other hand, our results also showed that for both diffusion and convection under thermal gradient, this NMD effect is increased by lower gas pressure, bigger temperature gradient and lower average temperature, which indicate that the nuclear spin effect may

  7. Three-dimensional electrical conductivity of the Pampean Shallow Subduction Region of Argentina near 33S and of the Payunia region of Argentina near 36.5S

    NASA Astrophysics Data System (ADS)

    Burd, Aurora Iris

    I present a three-dimensional (3D) interpretation of long period magnetotelluric sites: 117 from 31 - 35 S and 37 from 35 - 38 S in western Argentina. The first field area covers the most horizontal part of the Pampean shallow angle subduction of the Nazca slab and extends south into the more steeply dipping region. The second field area covers the < 2 Ma Payunia Basaltic Province (PBP). Data from each area were used in 3D Non-Linear Conjugate Gradient inversions. Three electrically conductive plumes occur at different locations in the crust and upper mantle: 1. A plume east of the horizontal Nazca slab rises from near the top of the mantle transition zone at 410 km, through the extrapolated location of the Nazca slab, and extends to the probable base of the lithosphere at 100 km depth. 2. A westward dipping plume beneath the PBP rises from roughly 130 km depth to within 7 km of the surface, with two "tendrils"' approaching the surface beneath the Caldera Payun Matru and the Volcan Tromen. These regions have volcanism younger than 0.1 Ma with some volcanism possibly within the last 7000 years. This plume remains above the subducted Nazca slab. 3. An eastward dipping plume rises from at least 410 km depth to within 5 km of the surface while remaining above the subducted Nazca slab, with its shallowest portion beneath the southern region of the PBP, which has no volcanism younger than ~ 0.8 Ma. Model assessment via both forward modeling and additional inversion tested the veracity of these features. I interpret the plume near the horizontal Nazca slab as an indication of a slab "window"' in the Nazca slab &mdash stress within the slab and seismic tomography support the likelihood of a slab window in this location. I propose that the two plumes beneath the Payunia Basaltic Province were previously a single structure, but the resurgence of mantle shear flow following steepening of a middle to late Miocene shallow slab caused the original plume to be pulled north-westward and eventually "decapitated" to form the two present-day plumes. The west-ward dipping plume likely represents the source of much of the recent Payunia Basaltic Province volcanism.

  8. Analysis of High-Resolution Infrared and CARS Spectra of ³⁴S¹⁸O₃

    SciTech Connect

    Masiello, Tony; Vulpanovici, Nicolae; Barber, Jeffrey B.; Chrysostom, Engelene; Nibler, Joseph W.; Maki, Arthur; Blake, Thomas A.; Sams, Robert L.; Weber, Alfons

    2004-09-11

    As part of a series of investigations of isotopic forms of sulfur trioxide, high-resolution infrared and coherent anti-Stokes Raman spectroscopies were used to study the fundamental modes and several hot bands of 32S18O3. Hot bands originating from the v2 and v4 bending mode levels have been found to couple strongly to the IR-inactive v1 symmetric stretching mode through indirect Coriolis interactions and Fermi resonances. Coriolis coupling effects are particularly noticeable in 32S18O3 due to the close proximity of the v2 and v4 fundamental vibrations, whose deperturbed wavenumber values are 486.488 13(4) and 504.284 77(4) cm-1. The uncertainties in the last digits are shown in parentheses and are two standard deviations. From the infrared transitions, accurate rovibrational constants are deduced for all of the mixed states, leading to deperturbed values for v1, and of 1004.68(2), 0.000 713(2), and 0.000 348(2) cm-1, respectively. The Be value is found to be 0.310 820(2) cm-1, yielding an equilibrium bond length re of 141.7333(4) pm that is, within experimental error, identical to the value of 141.7339(3) pm reported previously for 34S18O3. With this work, precise and accurate spectroscopic constants have now been determined in a systematic and consistent manner for all the fundamental vibrational modes of the sulfur trioxide D3h isotopomeric forms 32S16O3, 34S16O3, 32S18O3, and 34S18O3.

  9. Isotopic geochemistry of acid thermal waters and volcanic gases from Zaō volcano in Japan

    NASA Astrophysics Data System (ADS)

    Kiyosu, Yasuhiro; Kurahashi, Makoto

    1984-08-01

    The chemical composition and D/H, {18O }/{16O } and {34S }/{32S } ratios have been determined for the acid hot waters and volcanic gases discharging from Zaō volcano in Japan. The thermal springs in Zaō volcano issue acid sulfate-chloride type waters (Zaō) and acid sulfate type waters (Kamoshika). Gases emitted at Kamoshika fumaroles are rich in CO 2, SO 2 and N 2, exclusive of H 2O. Chloride concentrations and oxygen isotope data indicate that the Zaō thermal waters issue a fluid mixture from an acid thermal reservoir and meteoric waters from shallow aquifers. The waters in the Zaō volcanic system have slight isotopic shifts from the respective local meteoric values. The isotopic evidence indicates that most of the water in the system is meteoric in origin. Sulfates in Zaō acid sulfate-chloride waters with δ34S values of around +15‰, are enriched in 34S compared to Zaō H 2S, while the acid sulfate waters at Kamoshika contain supergene light sulfate ( δ 34S = ˜ + 4‰ ) derived from volcanic sulfur dioxide from the volcanic exhalations. The sulfur species in Zaō acid waters are lighter in δ34S than those of other volcanic areas, reflecting the difference in total pressure.

  10. Single cell visualization of sulfur cycling in intertidal microbial mats

    NASA Astrophysics Data System (ADS)

    Dawson, K.; Green, A.; Orphan, V. J.

    2014-12-01

    Chemoautrophic microbial mats form in shallow intertidal pools adjacent to sulfidic hydrothermal vents in San Pedro, CA. Sulfide is primarily geologically derived. However, microscopy revealed deltaproteobacteria closely associated with Beggiatoa -like filaments, indicating an additional biogenic sulfide source, derived from sulfate reduction or sulfur disproportionation. At small scales the intercellular interaction of sulfide producing and sulfide consuming bacteria may play a important role in biogeochemical sulfur cycling. We explored the intracellular transfer of biologically derived sulfide in this system with triple and quadruple stable isotope labeling experiments: 13C, 15N, 33S, and 34S. Silicon wafers colonized by microbial mats in situ, were then incubated with 34SO42- or 34SO42- and 33S0 as well as 13C-acetate and 15NH4+and analyzed by fluorescent in situ hybridization (FISH) coupled to nanometer-scale secondary ion mass spectrometry (NanoSIMS). We observed enrichment of 34S and 33S in both deltaproteobacteria and sulfide oxidizing gammaproteobacteria. Greater enrichment relative to killed controls occurred in deltaproteobacteria than the sulfide oxidizers during both sulfate reducing (Δ34Sdelta-killed = 240‰, Δ34Sgamma-killed = 40‰) and sulfur disproportionating incubations (Δ33Sdelta-killed = 1730‰, Δ33Sgamma-killed = 1050‰). These results provide a direct visualization of interspecies sulfur transfer and indicate that biogenic sulfide derived from either sulfate or intermediate oxidation state sulfur species plays a role in sulfur cycling in this system.

  11. Highly accurate potential energy surface, dipole moment surface, rovibrational energy levels, and infrared line list for ³²S¹⁶O₂ up to 8000 cm⁻¹.

    PubMed

    Huang, Xinchuan; Schwenke, David W; Lee, Timothy J

    2014-03-21

    A purely ab initio potential energy surface (PES) was refined with selected (32)S(16)O2 HITRAN data. Compared to HITRAN, the root-mean-squares error (σ(RMS)) for all J = 0-80 rovibrational energy levels computed on the refined PES (denoted Ames-1) is 0.013 cm(-1). Combined with a CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), an infrared (IR) line list (denoted Ames-296K) has been computed at 296 K and covers up to 8000 cm(-1). Compared to the HITRAN and CDMS databases, the intensity agreement for most vibrational bands is better than 85%-90%. Our predictions for (34)S(16)O2 band origins, higher energy (32)S(16)O2 band origins and missing (32)S(16)O2 IR bands have been verified by most recent experiments and available HITRAN data. We conclude that the Ames-1 PES is able to predict (32/34)S(16)O2 band origins below 5500 cm(-1) with 0.01-0.03 cm(-1) uncertainties, and the Ames-296K line list provides continuous, reliable and accurate IR simulations. The K(a)-dependence of both line position and line intensity errors is discussed. The line list will greatly facilitate SO2 IR spectral experimental analysis, as well as elimination of SO2 lines in high-resolution astronomical observations. PMID:24655184

  12. Neutron Radii from Low Energy Pion Scattering.

    NASA Astrophysics Data System (ADS)

    Gyles, William

    Recent electron scattering measurements and muonic atom studies have allowed precise determinations of the charge distributions of nuclei. Measurements of the neutron distributions, however, have not progressed to this degree of sophistication, largely because of the uncertainties in the hadron-nucleus interaction. Charge distribution measurements provide good tests of nuclear structure calculations, but measurements of neutron distributions will provide independent constraints on these calculations and the potentials used. In this experiment, (pi)('-) differential cross section ratios were measured on pairs of isotopes (('36)S,('32)S), (('34)S,('32)S) with 50 MeV pions and (('26)Mg,('24)Mg) with 45 MeV pions. Absolute differential cross sections were also measured for ('32)S and ('24)Mg. Magnetic spectro -meters were used to collect the data. The cross section ratios were compared to optical model calcula-tions in which the parameters of a Fermi function representing the neutron distribution of the larger isotope of each pair were varied. The rms radius difference between the two isotopes producing the best fit was found to be independent of the details of the optical potential used, as long as the potential produced a fit to the absolute cross sections. The neutron distribution of the larger isotope was also rep-resented as a Fermi function modified by a sum of spherical Bessel functions, the coefficients of which were allowed to vary. The results for the rms radius differences were consistent with the Fermi function fits, except for ('34)S-('32)S, where the results differed by a full standard deviation. The rms radius differences found for the sulfur isotopes agreed with the results of shell-model calculations by Hodgson (Str82,Hod83). The extracted rms radius difference of the magnesium isotopes was one standard deviation less than the shell-model prediction. The results for the Fermi function fits, Fourier Bessell fits and the single particle potential (SPP

  13. The minor sulfur isotope composition of Cretaceous and Cenozoic seawater sulfate

    NASA Astrophysics Data System (ADS)

    Masterson, A. L.; Wing, Boswell A.; Paytan, Adina; Farquhar, James; Johnston, David T.

    2016-06-01

    The last 125 Myr capture major changes in the chemical composition of the ocean and associated geochemical and biogeochemical cycling. The sulfur isotopic composition of seawater sulfate, as proxied in marine barite, is one of the more perplexing geochemical records through this interval. Numerous analytical and geochemical modeling approaches have targeted this record. In this study we extend the empirical isotope record of seawater sulfate to therefore include the two minor sulfur isotopes, 33S and 36S. These data record a distribution of values around means of Δ33S and Δ36S of 0.043 ± 0.016‰ and -0.39 ± 0.15‰, which regardless of δ34S-based binning strategy is consistent with a signal population of values throughout this interval. We demonstrate with simple box modeling that substantial changes in pyrite burial and evaporite sulfate weathering can be accommodated within the range of our observed isotopic values.

  14. Sulfur isotope values in the sulfidic Frasassi cave system, central Italy: A case study of a chemolithotrophic S-based ecosystem

    NASA Astrophysics Data System (ADS)

    Zerkle, Aubrey L.; Jones, Daniel S.; Farquhar, James; Macalady, Jennifer L.

    2016-01-01

    Sulfide oxidation forms a critical step in the global sulfur cycle, although this process is notoriously difficult to constrain due to the multiple pathways and highly reactive intermediates involved. Multiple sulfur isotopes (δ34S and Δ33S) can provide a powerful tool for unravelling sulfur cycling processes in modern (and ancient) environments, although they have had limited application to systems with well-resolved oxidative S cycling. In this study, we report the major (δ34S) and minor (Δ33S) isotope values of sulfur compounds in streams and sediments from the sulfidic Frasassi cave system, Marche Region, Italy. These microaerophilic cave streams host prominent white biofilms dominated by chemolithotrophic organisms that oxidize sulfide to S0, allowing us to estimate S isotope fractionations associated with in situ sulfide oxidation and to evaluate any resulting isotope biosignatures. Our results demonstrate that chemolithotrophic sulfide oxidation produces 34S enrichments in the S0 products that are larger than those previously measured in laboratory experiments, with 34εS0-H2S of up to 8‰ calculated. These small reverse isotope effects are similar to those produced during phototrophic sulfide oxidation (⩽7‰), but distinct from the small normal isotope effects previously calculated for abiotic oxidation of sulfide with O2 (∼-5‰). An inverse correlation between the magnitude of 34εS0-H2S effects and sulfide availability, along with substantial differences in Δ33S, both support complex sulfide oxidation pathways and intracellular recycling of S intermediates by organisms inhabiting the biofilms. At the ecosystem level, we calculate fractionations of less than 40‰ between sulfide and sulfate in the water column and in the sediments. These fractionations are smaller than those typically calculated for systems dominated by sulfate reduction (>50‰), and contrast with the commonly held assumption that oxidative recycling of sulfide generally

  15. Multiple sulfur isotope systematics of Icelandic geothermal fluids and the source and reactions of sulfur in volcanic geothermal systems at divergent plate boundaries

    NASA Astrophysics Data System (ADS)

    Stefánsson, Andri; Keller, Nicole S.; Robin, Jóhann Gunnarsson; Ono, Shuhei

    2015-09-01

    Multiple sulfur isotope systematics of geothermal fluids at Krafla, Northeast Iceland, were studied in order to determine the source and reactions of sulfur in this system, as an example of a geothermal system hosted on a divergent plate boundary. Fluid temperatures ranged from 192 to 437 °C, and the fluids have low Cl concentration between ∼10 and ∼150 ppm, with liquid water and vapor being present in the reservoir. Dissolved sulfide (S-II) and sulfate (SVI) predominated in the water phase with trace concentrations of thiosulfate (S2O32-) whereas sulfide (S-II) was the only species observed in the vapor phase. The reconstructed sulfur isotope ratios of the reservoir fluids based on samples collected at surface from two-phase and vapor only well discharges indicated that δ34S and Δ33S of sulfide in the reservoir fluid ranged from -1.5 to +1.1‰ and -0.001 to -0.017‰, respectively, whereas δ34S and Δ33S of sulfate were significantly different and ranged from +3.4 to +13.4‰ and 0.000 to -0.036‰, respectively. Depressurization boiling upon fluid ascent coupled with progressive fluid-rock interaction and sulfide mineral (pyrite) formation results in the liquid phase becoming progressively isotopically lighter with respect to both δ34S and Δ33S. In contrast, H2S in the vapor phase and pyrite become isotopically heavier. The observed Δ33S and δ34S systematics for geothermal fluids at Krafla suggest that the source of sulfide in the reservoir fluids is the basaltic magma, either through degassing or upon dissolution of unaltered basalts. At high temperatures, insignificant SO4 was observed in the fluids but below ∼230 °C significant concentrations of SO4 were observed, the source inferred to be H2S oxidation. The two key factors controlling the multiple sulfur isotope systematics of geothermal fluids are: (1) the isotopic composition of the source material and (2) the isotope fractionation associated with aqueous and vapor speciation and how these

  16. Sulfur isotopic ratio of DMS and DMSP from Lake Kinneret

    NASA Astrophysics Data System (ADS)

    Sela-Adler, Michal; Said-Ahmad, Ward; Eckert, Werner; Kamyshny, Alexey; Sivan, Orit; Amrani, Alon

    2014-05-01

    Volatile Organic sulfur compounds (VOSC) such as dimethylsulfide (DMS) are an important source of biogenic sulfur to the atmosphere. The main precursor of DMS is dimethylsulfoniopropionate (DMSP), a common osmolyte in marine algae. Atmospheric release of VOS compounds contributes to the formation of sulfate aerosols. The latter are of global importance due to their role as cloud-condensation nuclei. VOSC are abundant in terrestrial environments as well and may be involved in important biogeochemical cycles. In lake sediments, another mechanism for the formation of DMS by H2S methylation may be important. The 34S/32S ratio (d34S values) of DMSP of marine surface water around the globe is very homogeneous ranging between +18.9 o to +20.3 o and the fractionation between DMSP and DMS is < +1 o (Amrani et al. 2013). The δ34S values of DMS and other VOSC in sediments should be 34S depleted, similar to its H2S precursor (Oduro et al., 2011). Our goal was to quantify the benthic DMS and DMSP emissions from the sediments of warm monomictic Lake Kinneret relative to their formation by surface water algae by using sulfur isotope ratios. Water column samples and sediment samples from Lake Kinneret were purged and trap in order to extract the VOSC and then introduced to a GC/MC-ICPMS for isotopic measurements (Amrani et al. 2013). The δ34S of DMSP in the water and sediment columns of Lake Kinneret a mesotrophic monomictic lake were measured. Our preliminary results show δ34S values for DMSP ranged between +10.3 o and +13.4 o in the water column. The sulfate δ34S values ranged between +12.6 o to +14.9 o. δ34S -DMSP in the sediment column showed similar values between +9.4 o and +13.0 o, indicating a similar sulfur source. Similar δ34S values obtain for other VOSC such as ethanethiol that contributes significantly to the VOSC of Lake Kinneret sediments. Amrani, A., W. Said-Ahmad,Y. Shaked, and R. P. Kiene. 2013. Sulfur isotopes homogeneity of oceanic DMSP and DMS. PNAS 110

  17. Using stable isotopes to monitor forms of sulfur during desulfurization processes: A quick screening method

    USGS Publications Warehouse

    Liu, Chao-Li; Hackley, Keith C.; Coleman, D.D.; Kruse, C.W.

    1987-01-01

    A method using stable isotope ratio analysis to monitor the reactivity of sulfur forms in coal during thermal and chemical desulfurization processes has been developed at the Illinois State Geological Survey. The method is based upon the fact that a significant difference exists in some coals between the 34S/32S ratios of the pyritic and organic sulfur. A screening method for determining the suitability of coal samples for use in isotope ratio analysis is described. Making these special coals available from coal sample programs would assist research groups in sorting out the complex sulfur chemistry which accompanies thermal and chemical processing of high sulfur coals. ?? 1987.

  18. Carbonyl sulfide detection with a thermoelectrically cooled midinfrared quantum cascade laser

    NASA Astrophysics Data System (ADS)

    Roller, Chad; Kosterev, Anatoliy A.; Tittel, Frank K.; Uehara, Kiyoji; Gmachl, Claire; Sivco, Deborah L.

    2003-11-01

    A compact absorption spectrometer with a midinfrared tunable quantum cascade laser operating at 4.86 μm (2054 cm-1) is used to measure lower concentrations of carbonyl sulfide (COS) in air. A detection sensitivity of ~30 parts in 109 of COS and the selectivity of two stable isotopes, 12C16O32S and 12C16O34S, are demonstrated. Specifically, the feasibility of detecting COS in expired human breath as a potential noninvasive medical diagnostic tool is investigated.

  19. Stable isotope ratio mass spectrometry of nanogram quantities of boron and sulfur

    NASA Astrophysics Data System (ADS)

    Wieser, Michael Eugene

    1998-09-01

    Instrumentation and analytical techniques were developed to measure isotope abundances from nanograms of sulfur and boron. Sulfur isotope compositions were determined employing continuous flow isotope ratio mass spectroscopy (CF-IRMS) procedures and AsS+ thermal ionization mass spectrometry techniques (AsS+-TIMS). Boron isotope abundances were determined by BO2/sp--TIMS. CF-IRMS measurements realized δ34S values from 10 μg sulfur with precisions of ±0.3/perthous. To extend sulfur isotope measurements to much smaller samples, a TIMS procedure was developed to measure 75As32S+ and 75As34S+ at masses 108 and 109 from 200 ng S on a Finnigan MAT 262 with an ion counter. This is possibly the smallest amount of sulfur which has been successfully analyzed isotopically. The internal precision of 32S/34S ratios measured by AsS+-TIMS was better than ±0.15 percent. δ34S-values calculated relative to the measured 32S/34S value of an IAEA AG2S standard (S-1) agreed with those determined by CF-IRMS to within ±3/perthous. The increasing sensitivity of S-isotope analyses permits hiterto impossible investigations e.g. sulfur in tree rings and ice cores. Boron isotope abundances were measured as BO2/sp- from 50 ng B using an older thermal ionization mass spectrometer which had been extensively upgraded including the addition of computer control electronics, sensitive ion current amplification and fiber optic data bus. The internal precisions of the measured 11B/10B ratios were ±0.15 percent and the precisions of δ11B values calculated relative to the accepted international standard (SRM-951) were ±3/perthous. Two applications of boron isotope abundance variations were initiated (1) ground waters of Northern Alberta and (2) coffee beans in different regions of the world. In the first it was demonstrated that boron isotopes could be used to trace boron released during steam injection of oil sands into the surrounding environment. Data from the second study suggest that boron

  20. Sulfur isotope composition of metasomatised mantle xenoliths from the Bultfontein kimberlite (Kimberley, South Africa): Contribution from subducted sediments and the effect of sulfide alteration on S isotope systematics

    NASA Astrophysics Data System (ADS)

    Giuliani, Andrea; Fiorentini, Marco L.; Martin, Laure A. J.; Farquhar, James; Phillips, David; Griffin, William L.; LaFlamme, Crystal

    2016-07-01

    Sulfur isotopes are a powerful geochemical tracer in high-temperature processes, but have rarely been applied to the study of mantle metasomatism. In addition, there are very limited S isotope data on sub-continental lithospheric mantle (SCLM) material. For cratonic regions, these data are restricted to sulfide inclusions in diamonds. To provide new constraints on the S isotope composition of the SCLM and on the source(s) of mantle metasomatic fluids beneath the diamondiferous Kimberley region (South Africa), we investigated the S isotope systematics of five metasomatised mantle xenoliths from the Bultfontein kimberlite. Pentlandite and chalcopyrite in these xenoliths were analysed by in situ secondary-ion mass spectrometry (SIMS), with bulk-rock material measured by gas source isotope ratio mass spectrometry techniques. Based on previous studies, the xenoliths experienced different types of metasomatism to one another at distinct times (∼180 and ∼90-80 Ma). Contained pentlandite grains show variable alteration to heazlewoodite (i.e. Ni sulfide) + magnetite. The in situ S isotope analyses of pentlandite exhibit a relatively restricted range between -5.9 and - 1.4 ‰δ34 S (compared to VCDT), with no statistically meaningful differences between samples. Chalcopyrite only occurs in one sample and shows δ34 S values between -5.4 and - 1.0 ‰. The bulk-rock Ssulfide isotope analyses vary between -3.4 and + 0.8 ‰δ34 S. Importantly, the only sample hosting dominantly fresh sulfides shows a bulk-rock δ34 S value consistent with the mean value for the sulfides, whereas the other samples exhibit higher bulk 34S/32S ratios. The differences between bulk-rock and average in situδ34 S values are directly correlated with the degree of sulfide alteration. This evidence indicates that the elevated 34S/32S ratios in the bulk samples are not due to the introduction of heavy S (commonly as sulfates) and are best explained by isotopic fractionation coupled with the removal

  1. Multiple sulfur isotope characteristics of 3.46-2.7 Ga sedimentary rocks from drill cores of the Archean Biosphere Drilling Project (Invited)

    NASA Astrophysics Data System (ADS)

    Watanabe, Y.; Ohmoto, H.

    2010-12-01

    As part of the Archean Biosphere Drilling Project (ABDP), we have determined the multiple sulfur isotope ratios and examined the mineralogical and geochemical characteristics of the sulfur-bearing minerals (e.g., pyrite, sphalerite, barite) and the host rocks (e.g., major and trace element chemistry; Corg, Ccarb and S contents; δ13Corg and δ13Ccarb) of >100 samples of sedimentary rocks from five ABDP drill cores in the Pilbara Craton, Western Australia. The total ranges of Δ33S and δ34S values of the studied samples are -0.9 to +1.2‰ and -4 to +8‰, respectively. We have found that the Δ33S and δ34S relationships show unique values depending on their depositional environment: (1) Pyrites in the 3.46 Ga Marble Bar Chert Member (ABDP #1), which were formed by submarine hydrothermal fluids, show no AIF-S (anomalously fractionated sulfur isotope) signatures: Δ33S = -0.08 to +0.08‰ and δ34S = -3.3 to +0.6‰ (n = 5). This indicates that the H2S presented in the submarine hydrothermal fluid, which was partly generated through seawater sulfate reduction by Fe2+, did not possess AIF-S signatures. (2) Pyrites in organic C-poor lacustrine shales of the 2.76 Ga Hardey Formation (ABDP #3) also show no or very little AIF-S signatures: Δ33S = -0.38 to +0.25‰ and δ34S = -2.7 to +1.9‰ (n = 18). (3) Pyrites in organic C-poor marine shales of the 2.92 Ga Mosquito Creek Formation (ABDP#5) show no or small negative AIF-S signatures: Δ33S = -0.59 to 0.19 ‰ and all positive δ34S = +1.4 to +7.7‰ (n = 24). (4) Pyrites in organic C-rich (> 1 wt%) and hydrothermally altered marine shales in the 3.46 Ga Panorama Formation (ABDP #2) show constant and small positive AIF-S signatures (+0.44 to +0.61‰) and the smallest variation in δ34S (-1.1 to +1.6‰) (n = 35). In contrast, pyrites in organic C-rich shales in the 2.72 Ga Mt. Roe Basalt show negative Δ33S = -0.50 to -0.10‰ and δ34S = -3.7 to 1.8‰ (n = 10). (5) Pyrites in stromatolitic carbonates of the 2.7 Ga

  2. Mass-dependent and Mass-independent Sulphur Isotope Fractionation Accompanying Thermal- and Photo-chemical Decomposition of Sulphur Bearing Organic Compounds

    NASA Astrophysics Data System (ADS)

    Oduro, Harry; Izon, Gareth; Ono, Shuhei

    2014-05-01

    The bimodal S-isotope record, specifically the transition from mass independent (MIF) to mass dependent fractionation (MDF), is perhaps the most widely cited line of evidence for an irreversible rise in atmospheric oxygen at ca. 2.4Ga. The production and preservation of S-MIF, manifested in both Δ33S and Δ36S, within the geological record are linked to atmospheric O2 via a number of arguments. However, to date, the only mechanism capable of generating S-MIF consistent with the Archaean sedimentary records involves gas-phase ultraviolet irradiation of SO21 photolysis. More recently, Δ33S S-MIF trends have been reported from en vitro thermochemical sulphate reduction (TSR) experiments, prompting authors to question the importance of S-MIF as a proxy for Earth oxidation2. Importantly, whilst emerging TSR experiments3,4 affirm the reported Δ33S trends2, these experiments fail to identify correlated S-MIF between Δ33S and Δ36S values3,4. Realization that S-MIF is confined to Δ33S during TSR, precludes TSR as a mechanism responsible for the origin of the Archaean S-MIF record but strongly suggests the effect originating from a magnetic isotope effect (MIE) associated with 33S nucleus3,4. Clearly, photochemical and thermochemical processes impart different Δ36S/Δ33S trends with significant variation in δ34S; however, a complete experimental elucidation of mechanisms responsible for the S-MIF and S-MIE signatures is lacking. Interestingly, a complete understanding of the S-isotope chemistry during thermal- and photo-chemical decomposition may reveal wavelength and thermal dependence archived in the sedimentary record. Here we extend the experimental database to explore the magnitude and sign of Δ36S/Δ33S and δ34S produced during both photo- and thermochemical processes. Here the organic sulphur compounds (OSC) utilized in these experiments carries diagnostic Δ36S/Δ33S patterns that differ from those reported from photolysis experiment SO2 and from the

  3. Exploring Archean seawater sulfate via triple S isotopes in carbonate associated sulfate.

    NASA Astrophysics Data System (ADS)

    Paris, G.; Fischer, W. W.; Sessions, A. L.; Adkins, J. F.

    2015-12-01

    Multiple sulfur isotope ratios in Archean sedimentary rocks provide powerful insights into the behavior of the ancient sulfur cycle, the redox state of fluid Earth, and the timing of the rise of atmospheric oxygen [1]. The Archean sulfur isotope record is marked by pronounced mass-independent fractionation (Δ33S≠0)—signatures widely interpreted as the result of SO2 photolysis from "short-wavelength" UV light resulting in a reduced phase carrying positive Δ33S values (ultimately recorded in pyrite) and an oxidized phase carrying negative Δ33S values carried by sulfate [2]. Support for this hypothesis rests on early laboratory experiments and observations of negative Δ33S from barite occurrences in mixed volcanic sedimentary strata in Mesoarchean greenstone terrains. Despite forming the framework for understanding Archean sulfur cycle processes, this hypothesis is still largely untested, notably due to the lack of sulfate minerals in Archean strata. Using a new MC-ICP-MS approach combined with petrography and X-ray spectroscopy we have generated a growing S isotope dataset from CAS extracted from Archean carbonates from a range of sedimentary successions, including: the 2.6 to 2.521 Ga Campbellrand-Malmani carbonate platform (Transvaal Supergroup, South Africa), 2.7 Ga Cheshire Formation (Zimbabwe), and 2.9 Ga Steep Rock Formation (Canada). Importantly, we observe positive δ34S and Δ33S values across a range of different lithologies and depositional environments. These results demonstrate that dissolved sulfate in seawater was characterized by positive Δ33S values—a result that receives additional support from recent laboratory and theoretical experiments [e.g. 4, 5]. [1] Farquhar et al., 2000, Science [2] Farquhar et al., 2001, Journal of Geophysical Research: Planets [3] Paris et al., 2014, Science. [4] Whitehill et al., 2013, Proceedings of the National Academy of Sciences. [5] Claire et al., 2014 Geochimica et Cosmochimica Acta

  4. Processes Affecting Tropospheric Ozone Inferred from Ozonesonde and Other Tracer Data from the R/V R H Brown Atlantic Cruise (37N-34S) in January-February 1999

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Doddridge, B. G.; Luke, W. T.; Johnson, J. E.; Witte, J. C.; Reynolds, R. M.; Johnson, B.; Oltmans, S. J.

    1999-01-01

    During the Aerosols-99 trans-Atlantic cruise from Norfolk, VA, to Cape Town, South Africa, 22 ozonesondes were launched from the NOAA R/V R H Brown between 17 Jan and 6 Feb 1999, with all sondes but one reaching 30 km. A composite of ozone profiles along the transect shows high free tropospheric ozone (up to 100 ppbv at 9 km) between 5N and 20S, a coherent feature straddling either side of the ITCZ. Latitudinal variations of tropospheric ozone are interpreted using correlative measurements of surface ozone, CO, water vapor, and aerosol optical thickness (column absorbance) measured from the ship. Elevated ozone in the lower troposphere results from photochemical reactions of precursors emitted by biomass burning north of the ITCZ. However, the greatest ozone mixing ratios are in the mid-troposphere south of the ITCZ, which gives evidence of interhemispheric transport. Column-integrated tropospheric ozone, 35 DU from 0-16 km, agrees with that derived from the TOMS satellite by the modified-residual method [Thompson and Hudson, 1999]. NCEP wind fields, ship-launched radiosondes and back trajectories are consistent with a picture of recirculating air parcels centered in the tropical Atlantic region which is identified with the maximum wave-one amplitude in total ozone seen in sondes and by satellite.

  5. Tracing sources of sulfur in the Florida Everglades.

    PubMed

    Bates, Anne L; Orem, William H; Harvey, Judson W; Spiker, Elliott C

    2002-01-01

    We examined concentrations and sulfur isotopic ratios (34S/32S, expressed as delta34S in parts per thousand [/1000] units) of sulfate in surface water, ground water, and rain water from sites throughout the northern Everglades to establish the sources of sulfur to the ecosystem. The geochemistry of sulfur is of particular interest in the Everglades because of its link, through processes mediated by sulfate-reducing bacteria, to the production of toxic methylmercury in this wetland ecosystem. Methylmercury, a neurotoxin that is bioaccumulated, has been found in high concentrations in freshwater fish from the Everglades, and poses a potential threat to fish-eating wildlife and to human health through fish consumption. Results show that surface water in large portions of the Everglades is heavily contaminated with sulfate, with the highest concentrations observed in canals and marsh areas receiving canal discharge. Spatial patterns in the range of concentrations and delta34S values of sulfate in surface water indicate that the major source of sulfate in sulfur-contaminated marshes is water from canals draining the Everglades Agricultural Area. Shallow ground water underlying the Everglades and rain water samples had much lower sulfate concentrations and delta34S values distinct from those found in surface water. The delta34S results implicate agricultural fertilizer as a major contributor to the sulfate contaminating the Everglades, but ground water under the Everglades Agricultural Area (EAA) may also be a contributing source. The contamination of the northern Everglades with sulfate from canal discharge may be a key factor in controlling the distribution and extent of methylmercury production in the Everglades. PMID:11837434

  6. Sulfur isotope mass-independent fractionation in impact deposits of the 3.2 billion-year-old Mapepe Formation, Barberton Greenstone Belt, South Africa

    NASA Astrophysics Data System (ADS)

    van Zuilen, M. A.; Philippot, P.; Whitehouse, M. J.; Lepland, A.

    2014-10-01

    Theoretical and experimental studies have shown that atmospheric SO2 isotopologue self-shielding effects in the 190-220 nm region of the solar spectrum are the likely cause for mass independent fractionation of sulfur isotopes (S-MIF). The main products of this photochemical reaction - SO3 and S0 - typically define a compositional array of ca. Δ33S34S = 0.06-0.14. This is at odds with the generally observed trend in Archean sulfides, which broadly defines an array of ca. Δ33S34S = 0.9. Various explanations have been proposed, including a diminution of δ34S caused by chemical and biogenic mass-dependent fractionation of sulfur isotopes (S-MDF), mixing with photolytic products produced during felsic volcanic events, or partial blocking of the low-wavelength part of the spectrum due to the presence of reduced atmospheric gases or an organic haze. Early in Earth history large meteorite impacts would have ejected dust and gas clouds into the atmosphere that shielded solar radiation and affected global climate. It is thus likely that at certain time intervals of high meteorite flux the atmosphere was significantly perturbed, having an effect on atmospheric photochemistry and possibly leaving anomalous sulfur isotopic signatures in the rock record. Here we describe the sulfur isotopic signatures in sulfides of spherule beds S2, S3 and S4 of the Barberton Greenstone Belt, South Africa. In particular, in spherule bed S3 - and to a lesser extent S4 - a trend of ca. Δ33S34S = 0.23 is observed that closely follows the expected trend for SO2-photolysis in the 190-220 nm spectral range. This suggests that an impact dust cloud (deposited as spherule beds), which sampled the higher region of the atmosphere, specifically incorporated products of SO2 photolysis in the 190-220 nm range, and blocked photochemical reactions at higher wavelengths (250-330 nm band). By implication, the generally observed Archean trend appears to be the result of mixing of different MIF

  7. Leishmaniasis Worldwide and Global Estimates of Its Incidence

    PubMed Central

    Vélez, Iván D.; Bern, Caryn; Herrero, Mercé; Desjeux, Philippe; Cano, Jorge; Jannin, Jean

    2012-01-01

    As part of a World Health Organization-led effort to update the empirical evidence base for the leishmaniases, national experts provided leishmaniasis case data for the last 5 years and information regarding treatment and control in their respective countries and a comprehensive literature review was conducted covering publications on leishmaniasis in 98 countries and three territories (see ‘Leishmaniasis Country Profiles Text S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, S25, S26, S27, S28, S29, S30, S31, S32, S33, S34, S35, S36, S37, S38, S39, S40, S41, S42, S43, S44, S45, S46, S47, S48, S49, S50, S51, S52, S53, S54, S55, S56, S57, S58, S59, S60, S61, S62, S63, S64, S65, S66, S67, S68, S69, S70, S71, S72, S73, S74, S75, S76, S77, S78, S79, S80, S81, S82, S83, S84, S85, S86, S87, S88, S89, S90, S91, S92, S93, S94, S95, S96, S97, S98, S99, S100, S101’). Additional information was collated during meetings conducted at WHO regional level between 2007 and 2011. Two questionnaires regarding epidemiology and drug access were completed by experts and national program managers. Visceral and cutaneous leishmaniasis incidence ranges were estimated by country and epidemiological region based on reported incidence, underreporting rates if available, and the judgment of national and international experts. Based on these estimates, approximately 0.2 to 0.4 cases and 0.7 to 1.2 million VL and CL cases, respectively, occur each year. More than 90% of global VL cases occur in six countries: India, Bangladesh, Sudan, South Sudan, Ethiopia and Brazil. Cutaneous leishmaniasis is more widely distributed, with about one-third of cases occurring in each of three epidemiological regions, the Americas, the Mediterranean basin, and western Asia from the Middle East to Central Asia. The ten countries with the highest estimated case counts, Afghanistan, Algeria, Colombia, Brazil, Iran, Syria, Ethiopia, North Sudan, Costa

  8. Stable isotope ratios of blood components and muscle to trace dietary changes in lambs.

    PubMed

    Biondi, L; D'Urso, M G; Vasta, V; Luciano, G; Scerra, M; Priolo, A; Ziller, L; Bontempo, L; Caparra, P; Camin, F

    2013-09-01

    Multielemental stable isotope ratio (SIR) analysis was used in lamb plasma, erythrocytes and muscle to detect the switch from a pasture- to a concentrate-based diet, with the aim of verifying the possibility to trace the change of feeding in animal tissues. During 89 days of experimental feeding, lambs were subjected to four dietary treatments: pasture (P), pasture followed by concentrate in the stall for either 14 days (P-S14) or 37 days (P-S37) or concentrate in the stall (S). Pasture and concentrate diets comprised C3 plants only and had different values of 13C/12C, 18O/16O, 2H/1H and 34S/32S ratios. Muscle 13C/12C and 34S/32S and plasma 13C/12C and 18O/16O ratios in P, P-S14 and P-S37 lambs were significantly different. A multivariate analytical approach revealed that 13C/12C and 18O/16O ratios in plasma were the most powerful variables for the discrimination among the dietary treatments. PMID:23597321

  9. Multiple sulfur-isotope signatures in Archean sulfates and their implications for the chemistry and dynamics of the early atmosphere.

    PubMed

    Muller, Élodie; Philippot, Pascal; Rollion-Bard, Claire; Cartigny, Pierre

    2016-07-01

    Sulfur isotopic anomalies (∆(33)S and ∆(36)S) have been used to trace the redox evolution of the Precambrian atmosphere and to document the photochemistry and transport properties of the modern atmosphere. Recently, it was shown that modern sulfate aerosols formed in an oxidizing atmosphere can display important isotopic anomalies, thus questioning the significance of Archean sulfate deposits. Here, we performed in situ 4S-isotope measurements of 3.2- and 3.5-billion-year (Ga)-old sulfates. This in situ approach allows us to investigate the diversity of Archean sulfate texture and mineralogy with unprecedented resolution and from then on to deconvolute the ocean and atmosphere Archean sulfur cycle. A striking feature of our data is a bimodal distribution of δ(34)S values at ∼+5‰ and +9‰, which is matched by modern sulfate aerosols. The peak at +5‰ represents barite of different ages and host-rock lithology showing a wide range of ∆(33)S between -1.77‰ and +0.24‰. These barites are interpreted as primary volcanic emissions formed by SO2 photochemical processes with variable contribution of carbonyl sulfide (OCS) shielding in an evolving volcanic plume. The δ(34)S peak at +9‰ is associated with non-(33)S-anomalous barites displaying negative ∆(36)S values, which are best interpreted as volcanic sulfate aerosols formed from OCS photolysis. Our findings confirm the occurrence of a volcanic photochemical pathway specific to the early reduced atmosphere but identify variability within the Archean sulfate isotope record that suggests persistence throughout Earth history of photochemical reactions characteristic of the present-day stratosphere. PMID:27330111

  10. Multiple sulphur and iron isotope composition of detrital pyrite in Archaean sedimentary rocks: A new tool for provenance analysis

    NASA Astrophysics Data System (ADS)

    Hofmann, Axel; Bekker, Andrey; Rouxel, Olivier; Rumble, Doug; Master, Sharad

    2009-09-01

    Multiple S ( δ34S and δ33S) and Fe ( δ56Fe) isotope analyses of rounded pyrite grains from 3.1 to 2.6 Ga conglomerates of southern Africa indicate their detrital origin, which supports anoxic surface conditions in the Archaean. Rounded pyrites from Meso- to Neoarchaean gold and uranium-bearing strata of South Africa are derived from both crustal and sedimentary sources, the latter being characterised by non-mass dependent fractionation of S isotopes ( Δ33S as negative as - 1.35‰) and large range of Fe isotope values ( δ56Fe between - 1.1 and 1.2‰). Most sediment-sourced pyrite grains are likely derived from sulphide nodules in marine organic matter-rich shales, sedimentary exhalites and volcanogenic massive sulphide deposits. Some sedimentary pyrite grains may have been derived from in situ sulphidised Fe-oxides, prior to their incorporation into the conglomerates, as indicated by unusually high positive δ56Fe values. Sedimentary sulphides without significant non-mass dependent fractionation of S isotopes were also present in the source of some conglomerates. The abundance in these rocks of detrital pyrite unstable in the oxygenated atmosphere may suggest factors other than high pO 2 as the cause for the absence of significant non-mass dependent fractionation processes in the 3.2-2.7 Ga atmosphere. Rounded pyrites from the c. 2.6 Ga conglomerates of the Belingwe greenstone belt in Zimbabwe have strongly fractionated δ34S, Δ33S and δ56Fe values, the source of which can be traced back to black shale-hosted massive sulphides in the underlying strata. The study demonstrates the utility of combined multiple S and Fe isotope analyses for provenance reconstruction of Archaean sedimentary successions.

  11. Multiple sulfur-isotope signatures in Archean sulfates and their implications for the chemistry and dynamics of the early atmosphere

    NASA Astrophysics Data System (ADS)

    Muller, Élodie; Philippot, Pascal; Rollion-Bard, Claire; Cartigny, Pierre

    2016-07-01

    Sulfur isotopic anomalies (∆33S and ∆36S) have been used to trace the redox evolution of the Precambrian atmosphere and to document the photochemistry and transport properties of the modern atmosphere. Recently, it was shown that modern sulfate aerosols formed in an oxidizing atmosphere can display important isotopic anomalies, thus questioning the significance of Archean sulfate deposits. Here, we performed in situ 4S-isotope measurements of 3.2- and 3.5-billion-year (Ga)-old sulfates. This in situ approach allows us to investigate the diversity of Archean sulfate texture and mineralogy with unprecedented resolution and from then on to deconvolute the ocean and atmosphere Archean sulfur cycle. A striking feature of our data is a bimodal distribution of δ34S values at ˜+5‰ and +9‰, which is matched by modern sulfate aerosols. The peak at +5‰ represents barite of different ages and host-rock lithology showing a wide range of ∆33S between ‑1.77‰ and +0.24‰. These barites are interpreted as primary volcanic emissions formed by SO2 photochemical processes with variable contribution of carbonyl sulfide (OCS) shielding in an evolving volcanic plume. The δ34S peak at +9‰ is associated with non–33S-anomalous barites displaying negative ∆36S values, which are best interpreted as volcanic sulfate aerosols formed from OCS photolysis. Our findings confirm the occurrence of a volcanic photochemical pathway specific to the early reduced atmosphere but identify variability within the Archean sulfate isotope record that suggests persistence throughout Earth history of photochemical reactions characteristic of the present-day stratosphere.

  12. Environmental Change in the Prelude to a Neoproterozoic Ice Age: Sulfur Isotope Evidence from the Shaler Supergroup, Northwest Territories, Canada

    NASA Astrophysics Data System (ADS)

    Kaufman, A. J.; Williams, B. P.; Johnston, D. T.; Farquhar, J.; Knoll, A. H.; Butterfield, N. J.; Rainbird, R.

    2006-05-01

    The >723 Ma Shaler Supergroup on Victoria Island in the Northwest Territories of Canada is unusual for marginal marine Neoproterozoic successions insofar as thickly bedded sulfate evaporites are preserved. This unique sedimentary window for the Neoproterozoic allows us to investigate isotopic changes in the oxidized sulfur reservoir in the run up to a potential ice age, which is evidenced by a strong negative δ13C excursion in Kilian Formation carbonates at the top of the interval. Similar carbon isotope anomalies are recorded in carbonates beneath glacial diamictites of broadly the same age from the Mackenzie Mountains in Canada and in the Otavi Group of northern Namibia. Stratigraphically coincident with the 8‰ drop in 13C abundances in the Kilian Formation is a 15‰ rise in 34S of bedded sulfates, to a maximum of near +30‰. Anti-correlated isotope trends of smaller magnitude are recorded in mixed carbonates and evaporites at the top of the underlying Minto Inlet Formation. Comparison of 33S and 34S abundances of Shaler sulfates with values modeled from the results of culture experiments suggests that both anaerobic sulfate reducers and aerobic sulfur disproportionators populated the shallow open ocean. Notably, the profound 34S enrichment in the Kilian Formation is not coupled with similar enrichments in 33S. This observation is consistent with a system primarily driven by an increase in pyrite burial. Given the presence of shallow marine evaporites it is unlikely that sulfate concentrations were limited at this time. We hypothesize that this flux was enhanced during sea level fall at the onset of an ensuing ice age by the spread of anoxic conditions in deep oceans populated by sulfate reducing bacteria.

  13. A new 33-s period in the SSS X-ray light curve of the nova LMC 2009a and confirmation of the 35 s modulation in KT Eri

    NASA Astrophysics Data System (ADS)

    Ness, J.-U.; Kuulkers, E.; Henze, M.; Schwarz, G.; Osborne, J. P.; Beardmore, A. P.; Dobrotka, A.; Piro, A. L.; Starrfield, S.

    2014-05-01

    In addition to four known systems with super soft source (SSS) X-ray emission ( We have searched for similar oscillations in all XMM-Newton and Chandra observations of all objects containing SSS emission, that is persistent SSS and novae during their SSS phase. ...

  14. Identification of sulfur sources and isotopic equilibria in submarine hot-springs using multiple sulfur isotopes

    NASA Astrophysics Data System (ADS)

    McDermott, Jill M.; Ono, Shuhei; Tivey, Margaret K.; Seewald, Jeffrey S.; Shanks, Wayne C.; Solow, Andrew R.

    2015-07-01

    Multiple sulfur isotopes were measured in metal sulfide deposits, elemental sulfur, and aqueous hydrogen sulfide to constrain sulfur sources and the isotopic systematics of precipitation in seafloor hydrothermal vents. Areas studied include the Eastern Manus Basin and Lau Basin back-arc spreading centers and the unsedimented basalt-hosted Southern East Pacific Rise (SEPR) and sediment-hosted Guaymas Basin mid-ocean ridge spreading centers. Chalcopyrite and dissolved hydrogen sulfide (H2S) δ34S values range from -5.5‰ to +5.6‰ in Manus Basin samples, +2.4‰ to +6.1‰ in Lau Basin samples, and +3.7‰ to +5.7‰ in SEPR samples. Values of δ34S for cubic cubanite and H2S range from -1.4‰ to +4.7‰ in Guaymas Basin samples. Multiple sulfur isotope systematics in fluid-mineral pairs from the SEPR and Lau Basin show that crustal host rock and thermochemical reduction of seawater-derived dissolved sulfate (SO4) are the primary sources of sulfur in mid-ocean ridge and some back-arc systems. At PACMANUS and SuSu Knolls hydrothermal systems in the Eastern Manus Basin, a significant contribution of sulfur is derived from disproportionation of magmatic sulfur dioxide (SO2), while the remaining sulfur is derived from crustal host rocks and SO4 reduction. At the sedimented Guaymas Basin hydrothermal system, sulfur sources include crustal host rock, reduced seawater SO4, and biogenic sulfide. Vent fluid flow through fresher, less-mature sediment supplies an increased quantity of reactant organic compounds that may reduce 34S-enriched SO4, while fluid interaction with more highly-altered sediments results in H2S characterized by a small, but isotopically-significant input of 34S-depleted biogenic sulfides. Near-zero Δ33S values in all samples implicate the abiotic processes of SO4 reduction and leaching of host rock as the major contributors to sulfur content at a high temperature unsedimented mid-ocean ridge and at a back-arc system. Δ33S values indicate that SO2

  15. Sulfur Isotopic Compositions of Individual Aerosol Particles from Below and Within Stratocumulus Clouds over the Southeast Pacific Ocean During VOCALS

    NASA Astrophysics Data System (ADS)

    Bose, M.; Anderson, J. R.; Twohy, C. H.; Williams, P.

    2012-12-01

    The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-Rex) was a large multi-national field experiment that collected data and samples from a region of the southeast Pacific with the world's largest stratocumulus cloud systems. Samples examined here are residues of cloud droplets and ambient particles from below the clouds collected during flights of the NCAR C-130 off the coast of Chile. Selected samples were studied using scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS) in order to contribute to the understanding of the source of non-sea-salt sulfate in this region. Particles in the size range from 0.2 to 1μm diameter on holey and lacey carbon were characterized by SEM combined with energy dispersive spectrometry (EDS), thus identifying sulfur-containing particles. Subsequently, sulfur ion imaging of identified sea salt, ammonium sulfate and sodium sulfate particles was done with the Cameca Ametek NanoSIMS 50L at Arizona State University. A <1pA Cs+ beam was rastered over 5×5μm2 or 10×10μm2 areas while secondary ions (12C-, 16O-, 32S-, 34S-, 35Cl-) and secondary electrons were collected simultaneously at high mass resolution (m/Δm>10000). Each measurement typically consists of 5 to 8 frames (~5.4 min/frame). NIST barium sulfate and ammonium sulfate particles were used as isotopic standards. Preliminary analyses on a small pool of VOCALS individual particles show a wide range in sulfur isotopic compositions (δ34S = -56 to +41‰). In addition, the in-cloud particles are enriched in 32S, while the ambient particles exhibit 34S excesses. Isotopic data on a large inventory of particles is being currently acquired, which will be presented at the meeting. Data will be used to investigate sulfur sources (marine vs. continental) and the processing of aerosols through sulfate formation.

  16. Correlation between multielement stable isotope ratio and geographical origin in Peretta cows' milk cheese.

    PubMed

    Manca, G; Franco, M A; Versini, G; Camin, F; Rossmann, A; Tola, A

    2006-03-01

    The aim of this study was to characterize the isotopic composition and protect "Peretta" cows' milk cheese, a typical product of Sardinia, against other cheeses of the same appearance sold under the same name, but made of raw materials from northern Europe. The study was concerned with 3 types of cheese: those produced in local dairies from milk from free-grazing or pasture-grazing cows in Sardinia (local dairy product), cheeses made on an industrial scale from milk produced by intensive farming in Sardinia (factory cheese), and cheeses made with raw materials imported from other countries (imported product). To distinguish the Sardinian cheeses from the imported product, the stable isotope ratios 13C/12C, 15N/14N, D/H, 34S/32S, and (18)O/(16)O were used. Determination of the isotopic data delta13C, delta15N, delta2H, and delta34S was performed in the casein fraction, whereas delta(18)O and delta13C were determined in the glycerol fraction. Measurements were performed by isotope ratio mass spectrometry. A comparison between mean values of the isotope ratios by statistical analysis (ANOVA and Tukey's test) showed that the greatest difference between the 3 types of cheese (local dairy, factory, and imported products) was in the 13C/12C, 34S/32S, and (18)O/(16)O isotope ratios. In the other parameters, either no differences (delta15N) or minimal differences (delta2H) were found. Evaluation of the data by multivariate statistical analysis (principal component analysis and hierarchical cluster analysis) revealed that the isotope characteristics of the factory products were similar to those of the cheeses produced from imported raw materials, whereas a difference was found between the local dairy-produced cheeses and the products in the other 2 categories. PMID:16507675

  17. Isotopic and Geochemical Tracers for U(VI) Reduction and U Mobility at an in Situ Recovery U Mine.

    PubMed

    Basu, Anirban; Brown, Shaun T; Christensen, John N; DePaolo, Donald J; Reimus, Paul W; Heikoop, Jeffrey M; Woldegabriel, Giday; Simmons, Ardyth M; House, Brian M; Hartmann, Matt; Maher, Kate

    2015-05-19

    In situ recovery (ISR) uranium (U) mining mobilizes U in its oxidized hexavalent form (U(VI)) by oxidative dissolution of U from the roll-front U deposits. Postmining natural attenuation of residual U(VI) at ISR mines is a potential remediation strategy. Detection and monitoring of naturally occurring reducing subsurface environments are important for successful implementation of this remediation scheme. We used the isotopic tracers (238)U/(235)U (δ(238)U), (234)U/(238)U activity ratio, and (34)S/(32)S (δ(34)S), and geochemical measurements of U ore and groundwater collected from 32 wells located within, upgradient, and downgradient of a roll-front U deposit to detect U(VI) reduction and U mobility at an ISR mining site at Rosita, TX, USA. The δ(238)U in Rosita groundwater varies from +0.61‰ to -2.49‰, with a trend toward lower δ(238)U in downgradient wells. The concurrent decrease in U(VI) concentration and δ(238)U with an ε of 0.48‰ ± 0.08‰ is indicative of naturally occurring reducing environments conducive to U(VI) reduction. Additionally, characteristic (234)U/(238)U activity ratio and δ(34)S values may also be used to trace the mobility of the ore zone groundwater after mining has ended. These results support the use of U isotope-based detection of natural attenuation of U(VI) at Rosita and other similar ISR mining sites. PMID:25909757

  18. S and O Isotope Studies of Microbial S Cycling in the Deep Biosphere of Marine Sediments: Eastern Equatorial Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Blake, R. E.; Bottcher, M. E.; Surkov, A. V.; Ferdelman, T. G.; Jorgensen, B. B.

    2004-12-01

    We have determined the oxygen (18O/16O) and sulfur (34S/32S) isotope ratios of porewater sulfate to depths of over 400 mbsf in sediments from open-ocean and upwelling sites in the Eastern Equatorial Pacific ocean. Sulfate δ 18O ranges from near-normal seawater values (9.5 permil) at organic-poor open-ocean sites, to approximately 30 permil at sites with higher organic matter content and higher associated microbial activity. Depth-correlative trends of δ 18O, δ 34S, alkalinity, methane, ammonium and the presence of sulfide, indicate significant oxidation of sedimentary organic matter by sulfate-reducing microbial populations as well as anaerobic oxidation of methane. δ 18O-SO4 values at low-activity sites reveal the presence of significant microbial sulfur-cycling activity despite relatively flat sulfate concentration and δ 34S profiles. This activity may include contributions from several processes including: enzyme-catalyzed equilibration between oxygen in sulfate and water superimposed upon microbial sulfate reduction, sulfide oxidation, and bacterial disproportionation of sulfur intermediates. Large isotope enrichment factors observed at low-activity sites (40-80 permil) likely reflect concurrent processes of: kinetic isotope fractionation, equilibrium fractionation between sulfate and water, and sulfide oxidation at low rates of sulfate reduction. Results of this study indicate that coupled measurements of S and O isotope ratios of porewater sulfate are a powerful tool for tracing microbial activity and sulfur cycling in marine sediments.

  19. Equilibrium oxygen isotope behavior of sulfate in marine sediments: A new paradigm

    NASA Astrophysics Data System (ADS)

    Blake, R.; Boettcher, M.; Surkov, A.; Ferdelman, T.; Jorgensen, B.

    2006-05-01

    We have determined the oxygen (18O/16O) and sulfur (34S/32S) isotope ratios of porewater sulfate to depths of over 400 mbsf in sediments from open-ocean and upwelling sites in the Eastern Equatorial Pacific ocean. Sulfate δ18O ranges from near-normal seawater values (9.5 permil) at organic-poor open-ocean sites, to approximately 30 permil at sites with higher organic matter content and higher associated microbial activity. Depth-correlative trends of δ18O, δ34S, alkalinity, methane, ammonium and the presence of sulfide, indicate significant oxidation of sedimentary organic matter by sulfate-reducing microbial populations as well as anaerobic oxidation of methane. δ18O ?SO4 values at low-activity sites reveal the presence of significant microbial sulfur-cycling activity despite relatively flat sulfate concentration and δ34S profiles. This activity may include contributions from several processes including: enzyme-catalyzed equilibration between oxygen in sulfate and water superimposed upon microbial sulfate reduction, sulfide oxidation, and bacterial disproportionation of sulfur intermediates. Positive correlation between water and sulfate δ18O values supports sulfate-water O isotope exchange as the dominant process controlling porewater sulfate δ18O values. Results of this study indicate that coupled measurements of S and O isotope ratios of porewater sulfate are essential for interpreting microbial sulfur cycling in marine sediments.

  20. Crystal structure of (+)-methyl (E)-3-[(2S,4S,5R)-2-amino-5-hy-droxy-meth-yl-2-tri-chloro-methyl-1,3-dioxolan-4-yl]-2-methyl-prop-2-enoate.

    PubMed

    Oishi, Takeshi; Yasushima, Daichi; Yuasa, Kihiro; Sato, Takaaki; Chida, Noritaka

    2016-03-01

    In the title compound, C10H14Cl3NO5, the five-membered dioxolane ring adopts an envelope conformation. The C atom at the flap, which is bonded to the hy-droxy-methyl substituent, deviates from the mean plane of other ring atoms by 0.357 (5) Å. There are two intra-molecular hydrogen bonds (O-H⋯N and N-H⋯O) between the hy-droxy and amino groups, so that O- and N-bound H atoms involved in these hydrogen bonds are each disordered with equal occupancies of 0.50. The methyl 2-methyl-prop-2-enoate substituent also shows a disordered structure over two sets of sites with refined occupancies of 0.482 (5) and 0.518 (5). In the crystal, mol-ecules are connected into a dimer by an O-H⋯O hydrogen bond. The dimers are further linked by N-H⋯O, C-H⋯N and C-H⋯O inter-actions, extending a sheet structure parallel to ([Formula: see text]01). PMID:27006804

  1. The Phosphorus, Sulfur, Argon, and Calcium Isotopic Composition of the Galactic Cosmic Ray Source

    NASA Astrophysics Data System (ADS)

    Ogliore, R. C.; Stone, E. C.; Leske, R. A.; Mewaldt, R. A.; Wiedenbeck, M. E.; Binns, W. R.; Israel, M. H.; von Rosenvinge, T. T.; de Nolfo, G. A.; Moskalenko, I. V.

    2009-04-01

    Galactic cosmic ray (GCR) measurements of the phosphorus, sulfur, argon, and calcium isotopes made by the Cosmic Ray Isotope Spectrometer aboard the Advanced Composition Explorer are reported over the energy range from ~100 to ~400 MeV nucleon-1. The propagation of cosmic rays through the Galaxy and heliosphere is modeled with constraints imposed by measurements. Isotopic source abundance ratios 31P/32S, 34S/32S, 38Ar/36Ar, and 44Ca/40Ca are deduced. The derived 31P/32S ratio is 2.34 ± 0.34 times larger than the solar system value, lending further credence to the suggestion that refractory elements are enriched in the GCRs due to the sputtering of ions off grains in the cores of superbubbles. By determining the GCR source abundances of argon (a noble gas) and calcium (a refractory), it is determined that material in grains is accelerated to GCR energies a factor of 6.4 ± 0.3 more efficiently than gas-phase material in this charge range. With this information, the dust fraction of phosphorus and sulfur in the interstellar material that is mixed with stellar ejecta to form the GCR seed material is found to be consistent with astronomical observations.

  2. Multiple sulfur and carbon isotope composition of sediments from the Belingwe Greenstone Belt (Zimbabwe): A biogenic methane regulation on mass independent fractionation of sulfur during the Neoarchean?

    NASA Astrophysics Data System (ADS)

    Thomazo, Christophe; Nisbet, Euan G.; Grassineau, Nathalie V.; Peters, Marc; Strauss, Harald

    2013-11-01

    To explore the linkage between mass-independent sulfur isotope fractionation (MIF-S) and δ13Corg excursions during the Neoarchean, as well as the contemporary redox state and biogeochemical cycling of carbon and sulfur, we report the results of a detailed carbon and multiple sulfur (δ34S, δ33S, δ36S) isotopic study of the ∼2.7 Ga Manjeri and ∼2.65 Ga Cheshire formations of the Ngezi Group (Belingwe Greenstone Belt, Zimbabwe). Multiple sulfur isotope data show non-zero Δ33S and Δ36S values for sediments older than 2.4 Ga (i.e. prior to the Great Oxidation Event, GOE), indicating MIF-S thought to be associated with low atmospheric oxygen concentration. However, in several 2.7-2.5 Ga Neoarchean localities, small-scale variations in MIF-S signal (magnitude) seem to correlate with negative excursion in δ13Corg, possibly reflecting a global connection between the relative reaction rate of different MIF-S source reaction and sulfur exit channels and the biogenic flux of methane into the atmosphere during periods of localized, microbiologically mediated, shallow surface-water oxygenation. The Manjeri Formation black shales studied here display a wide range of δ13Corg between -35.4‰ and -16.2‰ (average of -30.3 ± 6.0‰, 1σ), while the Cheshire Formation shales have δ13Corg between -47.7‰ and -35.1‰ (average -41.3 ± 3‰, 1σ). The δ34S values of sedimentary sulfides from Manjeri Formation vary between -15.15‰ and +2.37‰ (average -1.71 ± 4.76‰, 1σ), showing very small and mostly negative Δ33S values varying from -0.58‰ to 0.87‰ (average 0.02 ± 0.43‰, 1σ). Cheshire Formation black shale sulfide samples measured in this study have δ34S values ranging from -2.11‰ to 2.39‰ (average 0.25 ± 1.08‰, 1σ) and near zero and solely positive Δ33S anomalies between 0.14‰ and 1.17‰ (average 0.56 ± 0.29‰, 1σ). Moreover, Δ36S/Δ33S in the two formations are comparable with a slope of -1.38 (Manjeri Formation) and -1.67 (Cheshire

  3. Sulfur and Hydrogen Isotope Anomalies in Organic Compounds from the Murchison Meteorite

    NASA Astrophysics Data System (ADS)

    Cooper, G. W.; Thiemens, M. H.; Jackson, T.; Chang, S.

    1995-09-01

    Carbon, hydrogen and sulfur isotopic measurements have been made on individual members of a recently discovered class of organic sulfur compounds, alkyl sulfonates, in the Murchison meteorite. Cooper and Chang (1) reported the first carbon isotopic measurements of Murchison organic sulfonates, providing insight into potential synthetic mechanisms of these, and possibly other, organic species. Hydrogen isotopic measurements of the sulfonates now reveal deuterium excesses ranging from +660 to +2730 per mil. The deuterium enrichments indicate formation of the hydrocarbon portion of these compounds in a low temperature astrophysical environment consistent with that of dense molecular clouds. Measurement of the sulfur isotopes provide further constraints on the origin and mechanism of formation of these organic molecules. Recently, there has been growing documentation of sulfur isotopic anomalies in meteoritic material. Thiemens and Jackson (2) have shown that some bulk ureilites possess excess 33S and Thiemens et al. (3) have reported excess 33S in an oldhamite separate from Norton County. Rees and Thode (4) reported a large 33S excess in an Allende acid residue, however, attempts to verify this measurement have been unsuccessful, possibly due to the heterogeneous nature of the carrier phase. With the recognition that sulfur isotopes may reflect nebular chemistry, identification of potential carriers is of considerable interest. In the present study the three stable isotopes of sulfur were measured in methane sulfonate extracted from the Murchison meteorite. The isotopic composition was found to be delta 33S=2.48, delta 34S=2.49 and delta 36S = 6.76 per mil. Based upon analysis of more than 60 meteoritic, and numerous terrestrial samples, the mass fractionation lines are defined by 33Delta = delta 33S-0.50 delta 34S and 36Delta = delta 36S -1.97 delta 34S. From these relations a 33Delta = 1.24 per mil and 36Delta = 0.89 per mil is observed. These anomalies

  4. Combined Sulfur K-edge XANES Spectroscopy and Stable Isotope Analysis of Fulvic Acids and Groundwater Sulfate Identify Sulfur Cycling in a Karstic Catchment Area

    SciTech Connect

    Einsiedl,F.; Schafer, T.; Northrup, P.

    2007-01-01

    Chemical and isotope analyses on groundwater sulfate, atmospheric deposition sulfate and fulvic acids (FAs) associated sulfur were used to determine the S cycling in a karstic catchment area of the Franconian Alb, Southern Germany. Sulfur K-edge X-ray absorption near edge structure (XANES) spectroscopy provided information on the oxidation state and the mechanism of the incorporation of sulfur in FAs. During base flow {delta}{sup 34}S values of groundwater sulfate were slightly depleted to those of recent atmospheric sulfate deposition with mean amount-weighted {delta}{sup 34}S values of around + 3{per_thousand}. The {delta}{sup 18}O values of groundwater sulfate shifted to lower values compared to those of atmospheric deposition and indicated steadiness from base flow to peak flow. The reduced sulfur species (S{sub -1}/thiol; S{sub 0}/thiophene, disulfide, S{sub +2}2/sulfoxide) of soil FAs averaged around 49% of the total sulfur and {delta}{sup 34}S value in FAs was found to be 0.5{per_thousand}. The formation of polysulfides and thiols in FAs in concert with a decreasing isotope value of {delta}{sup 34}S in FAs with respect to those of atmospheric deposition sulfate suggests oxidation of H{sub 2}S, enriched in the {sup 32}S isotope, with organic material. The depletion of {delta}{sup 18}O-SO{sub 4}{sup 2-} by several per mil in groundwater sulfate with respect to those of atmospheric deposition is, therefore, consistent with the hypothesis that SO{sub 4}{sup 2-} has been cycled through the organic S pool as well as that groundwater sulfate is formed by oxidation of H{sub 2}S with organic matter in the mineral soil of the catchment area.

  5. Carbon and sulfur isotopic signatures of ancient life and environment at the microbial scale: Neoarchean shales and carbonates.

    PubMed

    Williford, K H; Ushikubo, T; Lepot, K; Kitajima, K; Hallmann, C; Spicuzza, M J; Kozdon, R; Eigenbrode, J L; Summons, R E; Valley, J W

    2016-03-01

    An approach to coordinated, spatially resolved, in situ carbon isotope analysis of organic matter and carbonate minerals, and sulfur three- and four-isotope analysis of pyrite with an unprecedented combination of spatial resolution, precision, and accuracy is described. Organic matter and pyrite from eleven rock samples of Neoarchean drill core express nearly the entire range of δ(13) C, δ(34) S, Δ(33) S, and Δ(36) S known from the geologic record, commonly in correlation with morphology, mineralogy, and elemental composition. A new analytical approach (including a set of organic calibration standards) to account for a strong correlation between H/C and instrumental bias in SIMS δ(13) C measurement of organic matter is identified. Small (2-3 μm) organic domains in carbonate matrices are analyzed with sub-permil accuracy and precision. Separate 20- to 50-μm domains of kerogen in a single ~0.5 cm(3) sample of the ~2.7 Ga Tumbiana Formation have δ(13) C = -52.3 ± 0.1‰ and -34.4 ± 0.1‰, likely preserving distinct signatures of methanotrophy and photoautotrophy. Pyrobitumen in the ~2.6 Ga Jeerinah Formation and the ~2.5 Ga Mount McRae Shale is systematically (13) C-enriched relative to co-occurring kerogen, and associations with uraniferous mineral grains suggest radiolytic alteration. A large range in sulfur isotopic compositions (including higher Δ(33) S and more extreme spatial gradients in Δ(33) S and Δ(36) S than any previously reported) are observed in correlation with morphology and associated mineralogy. Changing systematics of δ(34) S, Δ(33) S, and Δ(36) S, previously investigated at the millimeter to centimeter scale using bulk analysis, are shown to occur at the micrometer scale of individual pyrite grains. These results support the emerging view that the dampened signature of mass-independent sulfur isotope fractionation (S-MIF) associated with the Mesoarchean continued into the early Neoarchean, and that the connections

  6. 99Tcm-MAG3 renogram deconvolution in normal subjects and in normal functioning kidney grafts.

    PubMed

    González, A; Puchal, R; Bajén, M T; Mairal, L; Prat, L; Martin-Comin, J

    1994-09-01

    This study provides values of transit times obtained by 99Tcm- mercaptoacetyl triglycine (99Tcm-MAG3) renogram deconvolution for both normal subjects and kidney graft recipients. The analysis included 50 healthy kidney units from 25 volunteers and 28 normal functioning kidney grafts. The parameters calculated for the whole kidney (WK) and for the renal parenchyma (P) were: mean transit time (MTT) and times at 20% (T20) and 80% (T80) of renal retention function initial height. For healthy kidneys the WK MTT was 174 +/- 27 s and P MTT 148 +/- 22 s. The WK T20 values were 230 +/- 33 s and P T20 231 +/- 34 s. The WK T80 was 108 +/- 19 s and P T80 106 +/- 12 s. Whole kidney and parenchymal values of transit times for normal functioning kidney grafts do not present significant differences with respect to healthy kidneys. PMID:7816379

  7. Multimodal information Management: Evaluation of Auditory and Haptic Cues for NextGen Communication Displays

    NASA Technical Reports Server (NTRS)

    Begault, Durand R.; Bittner, Rachel M.; Anderson, Mark R.

    2012-01-01

    Auditory communication displays within the NextGen data link system may use multiple synthetic speech messages replacing traditional ATC and company communications. The design of an interface for selecting amongst multiple incoming messages can impact both performance (time to select, audit and release a message) and preference. Two design factors were evaluated: physical pressure-sensitive switches versus flat panel "virtual switches", and the presence or absence of auditory feedback from switch contact. Performance with stimuli using physical switches was 1.2 s faster than virtual switches (2.0 s vs. 3.2 s); auditory feedback provided a 0.54 s performance advantage (2.33 s vs. 2.87 s). There was no interaction between these variables. Preference data were highly correlated with performance.

  8. Cometary Isotopic Measurements

    NASA Astrophysics Data System (ADS)

    Bockelée-Morvan, Dominique; Calmonte, Ursina; Charnley, Steven; Duprat, Jean; Engrand, Cécile; Gicquel, Adeline; Hässig, Myrtha; Jehin, Emmanuël; Kawakita, Hideyo; Marty, Bernard; Milam, Stefanie; Morse, Andrew; Rousselot, Philippe; Sheridan, Simon; Wirström, Eva

    2015-12-01

    Isotopic ratios in comets provide keys for the understanding of the origin of cometary material, and the physical and chemical conditions in the early Solar Nebula. We review here measurements acquired on the D/H, 14N/15N, 16O/18O, 12C/13C, and 32S/34S ratios in cometary grains and gases, and discuss their cosmogonic implications. The review includes analyses of potential cometary material available in collections on Earth, recent measurements achieved with the Herschel Space Observatory, large optical telescopes, and Rosetta, as well as recent results obtained from models of chemical-dynamical deuterium fractionation in the early solar nebula. Prospects for future measurements are presented.

  9. Sulfur Isotope Variation in Basaltic Melt Inclusions from Krakatau Revealed by a Newly Developed Secondary Ion Mass Spectrometry Technique for Silicate Glasses

    NASA Astrophysics Data System (ADS)

    Mandeville, C. W.; Shimizu, N.; Kelley, K. A.; Cheek, L.

    2008-12-01

    Sulfur is a ubiquitous element with variable valance states (S2-, S0, S4+, S6+) allowing for its participation in a wide variety of chemical and biogeochemical processes. However, its potential as an isotopic tracer in magmatic processes has not been fully developed and is crucial to understanding of sulfur recycling in subduction zones and between Earth's major reservoirs, mantle, lithosphere and coupled hydrosphere-atmosphere. Previous studies of silicate glasses and melt inclusions have been hampered by lack of an in situ isotopic measurement technique with spatial resolution of 10 to 100 microns. We have developed a new secondary ion mass spectrometry (SIMS) analytical technique for measurement of 34S/32S ratios in silicate glasses utilizing the IMS 1280 at Woods Hole Oceanographic Institution. A beam of 133Cs+ ions with 13 keV energy and current of 1-2 nA is focused onto a 10 micron spot and rastered over 30 × 30 microns. A Normal Incidence Electron Gun was used to compensate excess charge. The rastered beam is then centered to the optical axis of the machine, and a mechanical aperture is placed on the image plane to limit the area of analysis to the central 15 × 15 microns. The energy slit width was adjusted to 50 eV. A mass resolving power of 5500 was sufficient for eliminating mass interferences. A suite of synthetic and natural glasses with δ34SVCDT values spanning from - 5.6‰ to 18.5‰ with SiO2 from 44-72 weight % were measured. Magnitude of the instrumental mass fractionation (α) for 34S/32S ratios is 0.991 and is constant for all the glasses measured despite their compositions. Precision of individual measurements of 34S/32S ratios is 0.4 ‰, or better. Preliminary δ34S measurements of olivine-hosted basaltic melt inclusions in pre- 1883 basaltic scoria from Krakatau volcano Indonesia vary from -5.6 to 7.9‰ with sulfur concentrations from 490 to 2170 ppm, respectively. Host olivines are Fo77-80 and inclusions generally need minor to no post

  10. Hydrated sulfates on Mars's surface: water cycle and S isotope tracking

    NASA Astrophysics Data System (ADS)

    Caracas, R.; Bobocioiu, E.

    2014-12-01

    We study a range of hydrated sulfate minerals from first-principles calculations based on density-functional and density-functional perturbation theory. We report the results extensively on the WURM website (http://wurm.info, Caracas and Bobcioiu, 2011). We find that hydration has a more pronounced effect on the spectroscopic properties than cation replacement. The Raman spectra of all phases present clear SO4 features that are easily identifiable. We use this to show one can use the vibrational spectroscopic information as an identification tool in a remote environment, like the Martian surface. Based on the computed vibrational results we analyze the S isotope partitioning. We observe that in general hydration favors enrichment in the lighter S isotope 32S with respect to the heavier 34S, which is accumulated in the less hydrous structures. Thus we show for the first time that the signature of 34S/32S partitioning could be observed by in situ spectroscopy on the surface of Mars. Finally we compute hydration energies. For example, in the hydrated magnesium sulfate series we find that epsomite and meridianiite with, respectively 7 and 11 water molecules per MgSO4 unit are particularly stable with respect to other individual or combinations of hydration states (Bobocioiu and Caracas, 2014). This can be related to the diurnal cycle of hydration and dehydration and hence it can improve the modeling of the water circulation on Mars. References: E. Bobocioiu, R. Caracas (2014) Stability and spectroscopy of Mg sulfate minerals. Role of hydration on sulfur isotope partitioning. Amer. Mineral., 99, 1216-1220. R. Caracas, E. Bobocioiu (2011) The WURM project - a freely available web-based repository of computed physical data for minerals. Amer. Mineral. 96, 437-444.

  11. Stable light isotope biogeochemistry of hydrothermal systems

    NASA Technical Reports Server (NTRS)

    Des Marais, D. J.

    1996-01-01

    The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of hydrothermal systems. Hydrothermal alteration of the 18O/16O and D/H values of minerals can be used to detect fossil systems and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of hydrothermal fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at hydrothermal temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2.

  12. Stable light isotope biogeochemistry of hydrothermal systems.

    PubMed

    Des Marais, D J

    1996-01-01

    The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of hydrothermal systems. Hydrothermal alteration of the 18O/16O and D/H values of minerals can be used to detect fossil systems and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of hydrothermal fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at hydrothermal temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2. PMID:9243011

  13. Support for an anaerobic sulfur cycle in two Canadian peatland soils

    NASA Astrophysics Data System (ADS)

    Blodau, Christian; Mayer, Bernhard; Peiffer, Stefan; Moore, Tim R.

    2007-06-01

    Sulfur cycling in peatlands may affect global CH4 emissions by suppression of methanogenesis through bacterial sulfate reduction (BSR). We sought evidence for anaerobic sulfur cycling in four peat mesocosms irrigated with sulfate at a loading of 0.8 and 3.3 g S m-2 yr-1. To this end we obtained concentration profiles of dissolved O2, C, S, and Fe, and determined 34S/32S ratios of sulfate, reduced inorganic sulfur (TRIS), and total sulfur. To estimate the importance of BSR for anaerobic respiration, peat was incubated with molybdate as inhibitor of BSR. In the mesocosms, pore water concentrations of dissolved sulfate and H2S adjusted to 5-20 μmol L-1 and 0-9 μmol L-1, respectively, whereas concentrations of CO2, CH4, and DOC reached millimolar levels. CO2 production was not explained by methanogenesis and net reduction of inorganic electron acceptors. In the shallow peat, H2S was produced and 34S in sulfate enriched by 3.6 to 6‰, indicating occurrence of BSR. Sulfate reducers also accounted for much of the metabolic activity. Addition of molybdate suppressed CO2 production by 20 to 50%. Deeper into the peat, the sulfate pool was apparently replenished from the peat matrix as sulfate became enriched in 32S, likely stemming from TRIS or organic sulfur in the peat. Sulfur was thus anaerobically cycled between oxidized and reduced pools. An electron acceptor capable of driving this cycle could not be conclusively identified. Regardless of this uncertainty, the results suggest that anaerobic S cycling can maintain BSR and potentially contribute to low methane production in soils of ombrotrophic bogs.

  14. Triple sulfur isotope composition of Late Archean seawater sulfate

    NASA Astrophysics Data System (ADS)

    Paris, G.; Fischer, W. W.; Sessions, A. L.; Adkins, J. F.

    2013-12-01

    Multiple sulfur isotope ratios in Archean sedimentary rocks have provided powerful insights into the behavior of the ancient sulfur cycle, the redox state of fluid Earth, and the timing of the rise of atmospheric oxygen [1]. Most processes fractionate sulfur isotopes in proportion to their mass differences, but the Archean sulfur isotope record is marked by pronounced mass-independent fractionation (MIF, Δ33S≠0). The origin of these signatures has been traditionally interpreted as the result of photolysis of SO2 from short wavelength UV light, with positive Δ33S values recorded in pyrite and negative Δ33S values in sulfate-bearing phases [2]. This long-held hypothesis rests on observations of negative Δ33S from enigmatic barite occurrences from mixed volcanic sedimentary strata in Mesoarchean greenstone terrains. Despite forming the framework for understanding Archean sulfur cycle processes [3], it is largely untested [3]. It is largely untested. Consequently, the biggest challenge to our current understanding of the early sulfur cycle is a poor understanding of the isotopic composition of seawater sulfate. Sulfate evaporite minerals are absent from Archean strata and the sulfur isotope record is written entirely by measurements of pyrite. Carbonate associated sulfate (CAS) provides an important archive for assaying the isotopic composition of ancient seawater sulfate It has been exploited in many studies of Phanerozoic and Proterozoic sulfate but have been only marginally used thus far for Archean samples because of the extremely low concentration of CAS in limestones and dolomites from this era. We have developed a novel MC-ICP-MS approach to solve this problem [4]. This new method lowers the detection limit by up to three orders of magnitude for δ34S and Δ33S measurements, enabling to work on a few nmols of sulfate which represent only tens of mg of sample powders micromilled from specific carbonate textures. Two stratigraphic sections from the 2

  15. An isotopic analysis of ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-06-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find an enrichment factor (δ34S) of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  16. An isotope view on ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-02-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find a δ34S value of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  17. An isotopic view of ionising radiation as a source of sulphuric acid

    NASA Astrophysics Data System (ADS)

    Enghoff, M. B.; Bork, N.; Hattori, S.; Meusinger, C.; Nakagawa, M.; Pedersen, J. O. P.; Danielache, S. O.; Ueno, Y.; Johnson, M. S.; Yoshida, N.; Svensmark, H.

    2012-04-01

    Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism remains undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find a d34S value of 8.7 ± 0.4 ‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

  18. Regional sulfate-hematite-sulfide zoning in the auriferous Mariana anticline, Quadrilátero Ferrífero of Minas Gerais, Brazil

    NASA Astrophysics Data System (ADS)

    Cabral, Alexandre Raphael; Koglin, Nikola; Strauss, Harald; Brätz, Helene; Kwitko-Ribeiro, Rogerio

    2013-10-01

    The distribution of mineral deposits, characterised as barite deposits, hematite-rich auriferous deposits and auriferous tourmaline-sulfide deposits, displays a regional sulfate-hematite-sulfide zoning along the thrust-delineated limbs of the Mariana anticline, in the south-eastern part of the Quadrilátero Ferrífero of Minas Gerais, Brazil. Cross-cut relationships of barite veins and sulfide lodes indicate that sulfidation occurred in a late-tectonic context, which is here attributed to the collapse of the ˜0.6-Ga Brasiliano thrust front. Reconnaissance S-isotopic data from barite and pyrite (Antônio Pereira barite deposit and its adjacent gold deposit, respectively), and arsenopyrite (Passagem de Mariana gold deposit), suggest a new interpretation for the hydrothermal fluid overprint in the Mariana anticline. The Antônio Pereira barite has Δ33S values that are near zero, constraining the sulfate source to rocks younger than 2.45 Ga. The barite-δ34S values are between +19.6 and +20.8 ‰. The Passagem arsenopyrite and tourmaline have Co/Ni ratios that define a positive linear trend with the Antônio Pereira pyrite. The latter has homogenous δ34S values, between +8.8 and +8.9 ‰, which are compatible with thermochemical reduction of aqueous sulfate with the S-isotopic composition of the Antônio Pereira barite.

  19. A Multi-Technique Approach to Understanding Camp-Wide Mineralization Processes in Archean VMS Deposits

    NASA Astrophysics Data System (ADS)

    Sharman, E. R.; Wing, B.; Taylor, B.; Jonasson, I.; Farquhar, J.; Dubé, B.

    2009-05-01

    Volcanogenic Massive Sulphide (VMS) deposits form on or below the seafloor, in association with submarine extrusive volcanism, and reflect the hydrothermal concentration of ore-forming components originating from various reservoirs within the submarine environment. A defining question about VMS deposits is the relative contributions of different sulfur sources to mineralization. Standard models for VMS formation include contributions from reduction of seawater sulfate, remobilization of sedimentary sulfur, and volcanic sources (e.g., direct magmatic degassing, hydrothermal dissolution of sulfides in volcanic wall rocks). We are using an array of geochemical techniques to assess a suite of sulphide mineral separates collected from numerous VMS deposits within the Archean Noranda camp of the Abitibi Belt, Superior Province, Canada. These techniques include ICP-MS analyses of dissolved sulphide separates, microprobe analysis, and multiple sulphur isotope analyses. Multiple sulphur isotope analysis provides a new and powerful tool for interpreting Archean ore deposits. In pre-2.45 Ga rocks, multiple sulphur isotope analyses (δ33S, δ34S, and δ36S) document mass-independent sulphur isotope fractionation (δ33S≠0.515×δ34S, δ36S≠1.9×δ34S), likely expressed because of the lack of an oxygenated atmosphere. Ore-forming processes in VMS deposits cannot create mass-independent fractionation; they can only dilute it away. Trace element geochemistry of sulphides has been used to identify where in a VMS system these minerals form, with contributions from sources such as sea-water, or from a plume having different geochemical 'footprints'. Coupled with multiple sulphur isotope measurements, trace element geochemistry can be used to help identify sulphur sources within Archean VMS deposits and can be used to interpret camp-wide ore-forming processes and controls on mineralization. This will in turn allow for a more comprehensive understanding of VMS mineralization

  20. Sulfur concentration and isotopic variation in apatites from granitic to granodioritic plutons of a Cretaceous Cordilleran Batholith

    NASA Astrophysics Data System (ADS)

    Economos, R. C.

    2012-12-01

    Apatite is a common igneous accessory mineral with a high saturation temperature which can therefore crystallize over a significant portion of magmatic compositional space. Sulfur presents an opportunity to identify zoning in apatites. Unlike other trace elements, sulfur is relatively immobile in the apatite crystal structure and can be present in typical concentrations up to 1500 - 2000 ppm (or 0.5 to 1 wt% SO3). Sulfur concentration zoning in igneous apatites from ore producing magmatic systems has been identified (Streck and Dilles, 1998), but the interpretation of the cause of this zoning remains an open question. δ34S isotopic ratios of whole apatites have been used to track isotopic evolution associated with changes in magma fO2 and eruptive degassing (Rye, 2005). The presented work combines sulfur concentration mapping in zoned apatite crystals with in-situ SIMS 34S and 32S isotope measurements. Apatites were extracted from granite to granodiorite samples from the Cadiz Valley Batholith in the central Mojave Desert. This batholith is related to the pulse of Cretaceous Cordilleran magmatism that generated large batholiths in the Sierra Nevada and the Penninsular Ranges. The Mojave segment of the Cretaceous arc is unique in their construction into a full thickness of continental crust which exerted a strong influence on magmatic compositions. Apatite grains were mounted parallel to C axes, ground until grains were approximately bisected, and analyzed by Electron Microprobe at UCLA, for CaO, P2O5, SO3 and SiO2. Grains were surveyed and those yielding anomalous SO3 contents were investigated by micron-scale concentration mapping. Typical SO3 concentrations of apatites from all samples were ~0.2 wt%, while 8 to 10% of apatite grains from two samples contained cores with concentrations ranging up to 0.5 wt%. The sulfur zoning in these samples is oscillatory, in some grains representing 5 to 6 repetitions of high and low concentrations. Based on these textures

  1. Evaluating the earliest traces of Archean sub-seafloor life by NanoSIMS

    NASA Astrophysics Data System (ADS)

    Mcloughlin, N.; Grosch, E. G.; Kilburn, M.; Wacey, D.

    2012-12-01

    The Paleoarchean sub-seafloor has been proposed as an environment for the emergence of life with titanite microtextures in pillow lavas argued to be the earliest traces of microbial micro-tunneling (Furnes et al. 2004). Here we use a nano-scale ion microprobe (NanoSIMS) to evaluate possible geochemical traces of life in 3.45 Ga pillow lavas of the Barberton Greenstone Belt, South Africa. We investigated both surface and drill core samples from the original "Biomarker" outcrop in the Hooggenoeg Fm. Pillow lava metavolcanic glass contain clusters of segmented microcrystalline titanite filaments, ~4μm across and <200μm in length. Their size, shape and distribution have been directly compared to those found in recent oceanic crust. Thus it has been argued that they are the mineralized remains of tunnels formed by microbes that etched volcanic glass in the Archean sub-seafloor (Furnes et al 2004; Banerjee et al. 2006). Elemental mapping by NanoSIMS was undertaken to investigate reports of enrichments in carbon (possibly also nitrogen) along the margins of the microtextures previously interpreted as decayed cellular remains. We mapped for 12C-, 26CN-, 32S- along with 16O-, 28Si-, 24Mg+,27Al+, 40Ca+, 48Ti+ and 56Fe+ in chlorite and quartz hosted examples. The 12C- or 26CN- linings were not found along the margins of the microtextures in neither the original, nor the drill core samples, despite NanoSIMS being a more sensitive and higher-spatial-resolution technique than earlier microprobe X-ray maps. The absence of organic linings in these samples excludes a key line of evidence previously used to support the biogenicity of the microtextures. Sulfur isotopes 32S and 34S were measured by NanoSIMS on two types of sulfide: i) small sulfides (1-15μm) intimately associated with the microtextures and; ii) larger sulfides (10-60μm) that cross-cut the microtextures and are disseminated near a quartz-carbonate vein. The sulfide inclusions in the microtextures have strongly

  2. Changes in depth-transect redox conditions spanning the end-Permian mass extinction and their impact on the marine extinction: Evidence from biomarkers and sulfur isotopes

    NASA Astrophysics Data System (ADS)

    Kaiho, Kunio; Oba, Masahiro; Fukuda, Yoshihiko; Ito, Kosuke; Ariyoshi, Shun; Gorjan, Paul; Riu, Yuqing; Takahashi, Satoshi; Chen, Zhong-Qiang; Tong, Jinnan; Yamakita, Satoshi

    2012-08-01

    Changes in redox conditions during the Changhsingian to Griesbachian spanning the end-Permian mass extinction were recently reported based on analyses of organic molecules. We provide more precise organic-molecular data, that detail redox conditions spanning the end-Permian mass extinction at different palaeowater depths in the neritic Palaeotethys (estimated water depths: 10, 40, 100, and 200 m; Bulla, Huangzhishan, Meishan, and Chaohu sections, respectively) during this period. Here we propose that a change from occasional euxinia to anoxia in the shallow Palaeotethys occurred at the time of the mass extinction intercalated with oxic pulses. The second extinction at 0.7 myr after the main extinction was also caused by anoxia. New and published sulfur-isotope ratios (34S/32S) measured in carbonate-associated sulfate from the neritic Palaeotethys and in sulfide from pelagic central Panthalassa sediments show high values during the Changhsingian, consistent with the development of euxinia. The mass extinction coincided with a global fall in δ34S values, as well as a shift in δ13C values, indicating a global oxidation of H2S. This organic and isotopic geochemistry implies that accumulation of hydrogen sulfide in intermediate and deep waters followed by oxidation of hydrogen sulfide led to dissolved oxygen consumption, surface-water anoxia, and acidification, resulting in the end-Permian mass extinction in the seas.

  3. Determination of trace sulfur in biodiesel and diesel standard reference materials by isotope dilution sector field inductively coupled plasma mass spectrometry.

    PubMed

    Amais, Renata S; Long, Stephen E; Nóbrega, Joaquim A; Christopher, Steven J

    2014-01-01

    A method is described for quantification of sulfur at low concentrations on the order of mgkg(-1) in biodiesel and diesel fuels using isotope dilution and sector field inductively coupled plasma mass spectrometry (ID-SF-ICP-MS). Closed vessel microwave-assisted digestion was employed using a diluted nitric acid and hydrogen peroxide decomposition medium to reduce sample dilution volumes. Medium resolution mode was employed to eliminate isobaric interferences at (32)S and (34)S related to polyatomic phosphorus and oxygen species, and sulfur hydride species. The method outlined yielded respective limits of detection (LOD) and limits of quantification (LOQ) of 0.7 mg kg(-1) S and 2.5 mg kg(-1) S (in the sample). The LOD was constrained by instrument background counts at (32)S but was sufficient to facilitate value assignment of total S mass fraction in NIST SRM 2723b Sulfur in Diesel Fuel Oil at 9.06±0.13 mg kg(-1). No statistically significant difference at a 95% confidence level was observed between the measured and certified values for certified reference materials NIST SRM 2773 B100 Biodiesel (Animal-Based), CENAM DRM 272b and NIST SRM 2723a Sulfur in Diesel Fuel Oil, validating method accuracy. PMID:24331043

  4. Managed Metapopulations: Do Salmon Hatchery ‘Sources’ Lead to In-River ‘Sinks’ in Conservation?

    PubMed Central

    Johnson, Rachel C.; Weber, Peter K.; Wikert, John D.; Workman, Michelle L.; MacFarlane, R. Bruce; Grove, Marty J.; Schmitt, Axel K.

    2012-01-01

    Maintaining viable populations of salmon in the wild is a primary goal for many conservation and recovery programs. The frequency and extent of connectivity among natal sources defines the demographic and genetic boundaries of a population. Yet, the role that immigration of hatchery-produced adults may play in altering population dynamics and fitness of natural populations remains largely unquantified. Quantifying, whether natural populations are self-sustaining, functions as sources (population growth rate in the absence of dispersal, λ>1), or as sinks (λ<1) can be obscured by an inability to identify immigrants. In this study we use a new isotopic approach to demonstrate that a natural spawning population of Chinook salmon, (Oncorhynchus tshawytscha) considered relatively healthy, represents a sink population when the contribution of hatchery immigrants is taken into consideration. We retrieved sulfur isotopes (34S/32S, referred to as δ34S) in adult Chinook salmon otoliths (ear bones) that were deposited during their early life history as juveniles to determine whether individuals were produced in hatcheries or naturally in rivers. Our results show that only 10.3% (CI = 5.5 to 18.1%) of adults spawning in the river had otolith δ34S values less than 8.5‰, which is characteristic of naturally produced salmon. When considering the total return to the watershed (total fish in river and hatchery), we estimate that 90.7 to 99.3% (CI) of returning adults were produced in a hatchery (best estimate = 95.9%). When population growth rate of the natural population was modeled to account for the contribution of previously unidentified hatchery immigrants, we found that hatchery-produced fish caused the false appearance of positive population growth. These findings highlight the potential dangers in ignoring source-sink dynamics in recovering natural populations, and question the extent to which declines in natural salmon populations are undetected by monitoring

  5. Turnover of Stable Isotopes Due to Growth and Metabolism in Zebrafish, Danio Rerio

    NASA Astrophysics Data System (ADS)

    Tarboush, R.; MacAvoy, S.; Macko, S.; Connaughton, V.

    2002-05-01

    Stable isotope ratios of carbon (13C/12C), nitrogen (15 N/14N) and sulfur (34S/32S) in animal tissues can be used as tracers of the nutrient sources of organisms' diets and determining trophic interactions in ecosystems. The isotopic turnover of these elements in a predator's tissues reflects the isotopic signature of the predator's diet (the prey). The rate at which an organism takes up the isotopic signature of its food is correlated with its growth rate and/or metabolism. Hence unless baseline isotopic turnover rates are known, the isotopic signature of a consumer may lead to misinterpretation of predator-prey relationships. Laboratory studies provide isotopic turnover rates of organisms under controlled conditions, which serve as models for understanding the rates at which organisms in the field isotopically incorporate new diets. This study examines the isotopic turnover rates of carbon, nitrogen and sulfur in response to a dietary switch in young zebrafish, Danio rerio. Zebrafish, raised on commercial fish food (8.2 ñ 0.5%, d34S; were fed a new, isotopically distinct diet (2.9 ñ 0.5%, d34S) and the rate at which zebra fish muscle tissues changed towards the isotopic signature of their new food was monitored. Preliminary results show a change in the fish sulfur isotope composition of roughly 0.03% per day towards the sulfur isotope ratio of the new food. At the observed turnover rate, approximately 180 days would be required for the zebrafish muscle tissue to resemble a new food. The study is also investigating the importance of growth versus metabolism as a predictor of isotope turnover rate in zebra fish tissues.

  6. Analysis of High-Resolution Infrared and CARS Spectra of ³⁴S¹⁸O₃

    SciTech Connect

    Masiello, Tony; Barber, Jeffrey B.; Chrysostom, Engelene; Nibler, Joseph W.; Maki, Arthur; Weber, Alfons; Blake, Thomas A.; Sams, Robert L.

    2004-01-01

    Three fundamental modes and several hot bands of 34S18O3 have been investigated using both infrared spectroscopy and coherent anti-Stokes Raman scattering spectroscopy (CARS). Coriolis coupling effects are particularly noticeable in 34S18O3 due to the close proximity of the v2 and v4 fundamental vibrations, whose wavenumber values are 477.508 64(5) and 502.055 65(4) cm-1. The uncertainties in the last digits are shown in parentheses and are two standard deviations. Hot band transitions from v2, v4 levels give access to infrared inactive v2, v4 combination/overtone levels which interact strongly with levels of the Raman-active v1 symmetric stretching mode due to indirect Coriolis couplings, l-resonances, and Fermi resonances. The result is a complex v1 CARS Q- branch spectrum that is the most perturbed of the four SO3 isotopomers we have studied. The relative importance of these interaction terms on the v1 CARS spectrum is examined in some detail and accurate rovibrational constants are determined for all of the mixed states, leading to deperturbed values of 1004.662(24), 0.000 350 3(9), and 0.000 706 6(12) cm-1 for v1, α1B, and α1C, respectively. The B e value is found to be 0.310 817(12) cm-1, which gives an equilibrium bond length re of 141.7339(3) pm, in excellent agreement with values of 141.7340(1) and 141.7347(7) pm reported earlier for 32S16O3 and 34S16O3.

  7. Natural variations of copper and sulfur stable isotopes in blood of hepatocellular carcinoma patients

    NASA Astrophysics Data System (ADS)

    Balter, Vincent; Nogueira da Costa, Andre; Paky Bondanese, Victor; Jaouen, Klervia; Lamboux, Aline; Sangrajrang, Suleeporn; Vincent, Nicolas; Fourel, François; Télouk, Philippe; Gigou, Michelle; Lécuyer, Christophe; Srivatanakul, Petcharin; Bréchot, Christian; Albarède, Francis; Hainaut, Pierre

    2015-01-01

    The widespread hypoxic conditions of the tumor microenvironment can impair the metabolism of bioessential elements such as copper and sulfur, notably by changing their redox state and, as a consequence, their ability to bind specific molecules. Because competing redox state is known to drive isotopic fractionation, we have used here the stable isotope compositions of copper (65Cu/63Cu) and sulfur (34S/32S) in the blood of patients with hepatocellular carcinoma (HCC) as a tool to explore the cancer-driven copper and sulfur imbalances. We report that copper is 63Cu-enriched by ∼0.4‰ and sulfur is 32S-enriched by ∼1.5‰ in the blood of patients compared with that of control subjects. As expected, HCC patients have more copper in red blood cells and serum compared with control subjects. However, the isotopic signature of this blood extra copper burden is not in favor of a dietary origin but rather suggests a reallocation in the body of copper bound to cysteine-rich proteins such as metallothioneins. The magnitude of the sulfur isotope effect is similar in red blood cells and serum of HCC patients, implying that sulfur fractionation is systemic. The 32S-enrichment of sulfur in the blood of HCC patients is compatible with the notion that sulfur partly originates from tumor-derived sulfides. The measurement of natural variations of stable isotope compositions, using techniques developed in the field of Earth sciences, can provide new means to detect and quantify cancer metabolic changes and provide insights into underlying mechanisms.

  8. Natural variations of copper and sulfur stable isotopes in blood of hepatocellular carcinoma patients

    PubMed Central

    Balter, Vincent; Nogueira da Costa, Andre; Bondanese, Victor Paky; Jaouen, Klervia; Lamboux, Aline; Sangrajrang, Suleeporn; Vincent, Nicolas; Fourel, François; Télouk, Philippe; Gigou, Michelle; Lécuyer, Christophe; Srivatanakul, Petcharin; Bréchot, Christian; Albarède, Francis; Hainaut, Pierre

    2015-01-01

    The widespread hypoxic conditions of the tumor microenvironment can impair the metabolism of bioessential elements such as copper and sulfur, notably by changing their redox state and, as a consequence, their ability to bind specific molecules. Because competing redox state is known to drive isotopic fractionation, we have used here the stable isotope compositions of copper (65Cu/63Cu) and sulfur (34S/32S) in the blood of patients with hepatocellular carcinoma (HCC) as a tool to explore the cancer-driven copper and sulfur imbalances. We report that copper is 63Cu-enriched by ∼0.4‰ and sulfur is 32S-enriched by ∼1.5‰ in the blood of patients compared with that of control subjects. As expected, HCC patients have more copper in red blood cells and serum compared with control subjects. However, the isotopic signature of this blood extra copper burden is not in favor of a dietary origin but rather suggests a reallocation in the body of copper bound to cysteine-rich proteins such as metallothioneins. The magnitude of the sulfur isotope effect is similar in red blood cells and serum of HCC patients, implying that sulfur fractionation is systemic. The 32S-enrichment of sulfur in the blood of HCC patients is compatible with the notion that sulfur partly originates from tumor-derived sulfides. The measurement of natural variations of stable isotope compositions, using techniques developed in the field of Earth sciences, can provide new means to detect and quantify cancer metabolic changes and provide insights into underlying mechanisms. PMID:25583489

  9. Microwave spectra and gas phase structural parameters for N-hydroxypyridine-2(1H)-thione.

    PubMed

    Daly, Adam M; Mitchell, Erik G; Sanchez, Daniel A; Block, Eric; Kukolich, Stephen G

    2011-12-22

    The microwave spectrum for N-hydroxypyridine-2(1H)-thione (pyrithione) was measured in the frequency range 6-18 GHz, providing accurate rotational constants and nitrogen quadrupole coupling strengths for three isotopologues, C(5)H(4)(32)S(14)NOH, C(5)H(4)(32)S(14)NOD, and C(5)H(4)(34)S(14)NOH. Pyrithione was found to be in a higher concentration in the gas phase than the other tautomer, 2-mercaptopyridine-N-oxide (MPO). Microwave spectroscopy is best suited to determine which structure predominates in the gas phase. The measured rotational constants were used to accurately determine the coordinates of the substituted atoms and provided sufficient data to determine some of the important structural parameters for pyrithione, the only tautomer observed in the present work. The spectra were obtained using a pulsed-beam Fourier transform microwave spectrometer, with sufficient resolution to allow accurate measurements of the (14)N nuclear quadrupole hyperfine interactions. Ab initio calculations provided structural parameters and quadrupole coupling strengths that are in very good agreement with measured values. The experimental rotational constants for the parent compound are A = 3212.10(1), B = 1609.328(7), and C = 1072.208(6) MHz, yielding the inertial defect Δ(0) = -0.023 amu·Å(2) for the C(5)H(4)(32)S(14)NOH isotopologue. The observed near zero inertial defect clearly indicates a planar structure. The least-squares fit structural analysis yielded the experimental bond lengths R(O-H) = 0.93(2) Å, R(C-S) = 1.66(2) Å, and angle (N-O-H) = 105(4)° for the ground state structure. PMID:22070758

  10. Natural variations of copper and sulfur stable isotopes in blood of hepatocellular carcinoma patients.

    PubMed

    Balter, Vincent; Nogueira da Costa, Andre; Bondanese, Victor Paky; Jaouen, Klervia; Lamboux, Aline; Sangrajrang, Suleeporn; Vincent, Nicolas; Fourel, François; Télouk, Philippe; Gigou, Michelle; Lécuyer, Christophe; Srivatanakul, Petcharin; Bréchot, Christian; Albarède, Francis; Hainaut, Pierre

    2015-01-27

    The widespread hypoxic conditions of the tumor microenvironment can impair the metabolism of bioessential elements such as copper and sulfur, notably by changing their redox state and, as a consequence, their ability to bind specific molecules. Because competing redox state is known to drive isotopic fractionation, we have used here the stable isotope compositions of copper ((65)Cu/(63)Cu) and sulfur ((34)S/(32)S) in the blood of patients with hepatocellular carcinoma (HCC) as a tool to explore the cancer-driven copper and sulfur imbalances. We report that copper is (63)Cu-enriched by ∼0.4‰ and sulfur is (32)S-enriched by ∼1.5‰ in the blood of patients compared with that of control subjects. As expected, HCC patients have more copper in red blood cells and serum compared with control subjects. However, the isotopic signature of this blood extra copper burden is not in favor of a dietary origin but rather suggests a reallocation in the body of copper bound to cysteine-rich proteins such as metallothioneins. The magnitude of the sulfur isotope effect is similar in red blood cells and serum of HCC patients, implying that sulfur fractionation is systemic. The (32)S-enrichment of sulfur in the blood of HCC patients is compatible with the notion that sulfur partly originates from tumor-derived sulfides. The measurement of natural variations of stable isotope compositions, using techniques developed in the field of Earth sciences, can provide new means to detect and quantify cancer metabolic changes and provide insights into underlying mechanisms. PMID:25583489

  11. On-line Sulfur Isotope Determination by Hydride Generation coupled to MC-ICP-MS

    NASA Astrophysics Data System (ADS)

    Callac, Nolwenn; Rouxel, Olivier; Ponzevera, Emmanuel; Godfroy, Anne

    2010-05-01

    In seafloor hydrothermal systems, Sulfur is an important element present in various forms such as sulfate, elemental sulfur or sulfide in hydrothermal fluids and pore waters. Sulfur, as either electron donor or acceptor, is one element that enables support for microbial life in the deep biosphere. Traditionally, measurements of 34S/32S ratios (δ34S) are performed using gas-source mass spectrometry (GS-MS) in which sulfur is introduced as gaseous SO2 or SF6 species. We recently developed an alternate technique for the accurate and precise determination of 34S/32S ratios in sulfur-bearing minerals using solution and laser ablation multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) (Craddock et al, 2008; Chemical Geology 253 p102-113). We examined and determined rigorous corrections for analytical difficulties such as instrumental mass bias, unresolved isobaric interferences, blanks, and laser ablation- and matrix-induced isotopic fractionation. In particular, the use of high resolution sector-field mass spectrometry has been shown to remove major isobaric interferences from O2+ while standard-sample bracketing allowed the correcting instrumental mass bias of unknown samples. Here, we evaluate a new method for the direct determination of S isotope in environmental samples using on-line generation of hydrogen sulfide coupled to MC-ICPMS. It is expected that the introduction of volatile S-species in the plasma torch will lower the minimum amounts of S required per analysis by more than 1 order of magnitude while permitting matrix-free isotope analysis. An important aim of this study was to determine optimal procedures to overcome analytical difficulties such as instrumental mass bias, unresolved isobaric interferences, blanks, and isotope fractionation induced during hydrogen sulfide generation. We initially applied this method to investigate the diversity of sulfur isotope fractionations during microbial sulfur-reducing or sulfate-reducing at

  12. A combined chemical, isotopic and microstructural study of pyrite from roll-front uranium deposits, Lake Eyre Basin, South Australia

    NASA Astrophysics Data System (ADS)

    Ingham, Edwina S.; Cook, Nigel J.; Cliff, John; Ciobanu, Cristiana L.; Huddleston, Adam

    2014-01-01

    depositional conditions and sources of both sulfide and uranium mineralization and an improved understanding of pyrite geochemistry can also underpin an effective vector for uranium exploration at Beverley North and other sedimentary systems of the Lake Eyre Basin, as well as in comparable geological environments elsewhere. Average intensity of 32S signal in counts per second × 108.Drift corrected 34S/32S prior to IMF calibration.Two-sigma propagated uncertainty on individual measurements.

  13. Electron excitation cross sections for the 2s(2)2p(3)4S(O) -- 2s(2)2p(3)2D(O) (forbidden) and 4S(O) -- 2s2p(4) 4P (resonance) transitions in O II

    NASA Technical Reports Server (NTRS)

    Zuo, M.; Smith, Steven J.; Chutjian, A.; Williams, I. D.; Tayal, S. S.; Mclaughlin, Brendan M.

    1995-01-01

    Experimental and theoretical excitation cross sections are reported for the first forbidden transition 4S(O) -- 2S(2)2p(3) 2D(O) (lambda-lambda 3726, 3729) and the first allowed (resonance) transition 4S(O) -- 2s2p(4) 4P(lambda-833) in O II. Use is made of electron energy loss and merged-beams methods. The electron energy range covered is 3.33 (threshold) to 15 eV for the S -- D transition, and 14.9 (threshold) to 40 eV for the S -- P transition. Care was taken to assess and minimize the metastable fraction of the O II beam. An electron mirror was designed and tested to reflect inelastically backscattered electrons into the forward direction to account for the full range of polar scattering angles. Comparisons are made between present experiments and 11-state R-matrix calculations. Calculations are also presented for the 4S(O) -- 2s(2)2p(3)2P(O) (lambda-2470) transition.

  14. Biogeochemistry of sulfur in the Vienna Woods: Study of sulfur stable isotope ratios by MC-ICP-MS as indicator of biogeochemical S cycling

    NASA Astrophysics Data System (ADS)

    Hanousek, Ondrej; Berger, Torsten W.; Prohaska, Thomas

    2014-05-01

    Sulfur entering forest ecosystems originates mainly from combustion of fossil fuels. This source of sulfur has been strongly (by more than 95 %) reduced in last decades and recently, higher sulfur output (in soil solution or stream water) than sulfur input (in rain water) in an ecosystem was registered in many monitored forest ecosystems. This unbalance may be caused by weathering of sulfur-bearing rocks, desorption of sulfur adsorbed in soil in the past or (re)mineralization of organic sulfur compounds. This 'negative' balance leads to mobilization of base cations along with SO42- and as such to an acidification of soils. As hypothesis, δ34S/32S depletion in stream water will be observed if a considerable proportion of atmospherically deposited sulfate is cycled through the organic S pool. Rain water and soil solutions samples were collected for this study at 3 sites (beech stands) in the Vienna Woods, Austria twice a month from May 2010 to April 2012. Due to the expected sulfate concentration gradient with respect to the distance from a tree, sampling was carried out at 5 intervals from a stem. The sulfur concentration in the samples was determined by ion chromatography. Sulfur isotope ratios (δ34S/32SV CDT) were analyzed by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) in edge-resolution mode. The method was validated using IAEA-S-1 and IAEA-S-2 isotopic certified reference materials. The combined standard uncertainty of the measurement (uc = 0.10 %, k = 1) proves the suitability of the developed method. The concentration of sulfur in rain water showed expected behavior, with a seasonal maximum in winter months, in contrast to the corresponding δ34S/32SV CDT isotope ratios, where no or low seasonal trends were observed. The sulfur isotope ratios in soil solution samples show a dependence on the distance from a tree stem and the sampling depth with lower δ34S/32SV CDT ratios as compared to the precipitation. The measured isotopic

  15. Mass Independent Fractionation of Sulfur Isotopes during Thermochemical Sulfate Reduction: Implications in the Origins of Pyrite in Archean Sedimentary Rocks and Sulfur in Petroleum and Natural Gas

    NASA Astrophysics Data System (ADS)

    Watanabe, Y.; Ohmoto, H.; Naraoka, H.

    2006-12-01

    Geochemists generally agree that S-bearing compounds in petroleum and natural gas, as well as sulfides in the Mississippi Valley-type Zn-Pb deposits and shale/carbonate-hosted Zn-Pb deposits, mostly originated from the H2S that was generated from thermochemical sulfate reduction (TSR) at T = ~100-200°C, utilizing anhydrite-derived SO42- and organic matter in large sedimentary basins. However, the details of mechanisms and conditions (e.g., specific organic molecules) for TSR have not been understood. For example, previous laboratory experiments focused on carbohydrates (e.g., sugar, CH4), but they were unable to demonstrate TSR at temperatures below ~250°C, except when H2S (and/or S) was initially present. We were able to reduce a variety of sulfur-bearing compounds (native sulfur, sulfite, and sulfate) to H2S, without the initial presence of H2S, at temperatures as low as 150°C using amino acids, which are the most abundant organic molecules in living organisms. An extrapolation of the experimental data suggests the likelihood of TSR in amino acid-rich sediments at temperatures as low as ~100°C within a reasonable geologic time. With increasing valence of the starting S-compounds, from 0 (native sulfur) to 4+ (sulfite) to +6 (sulfate), the H2S production rates of TSR by amino acids significantly decrease, the kinetic isotope effects (Δ34S = δ34SH2S - δ34Sreactant) generally increase, and most interestingly the magnitude of mass-independent fractionation of sulfur (MIF-S) of the H2S (Δ^{33}S = δ^{33}S - 0.515xδ34S) increases. Therefore, we may be able to use theδ34S, δ^{33}S and Δ^{33} values of sulfur compounds in petroleum and natural gas to estimate the specific pathways and conditions for TSR in a specific sedimentary basin. The reducing power of amino acids is found to increase in simpler amino acids (i.e., glycine>alanine>arginine>histidine). According to some biochemical studies, the relative abundances of amino acids changed with evolution of

  16. Crystal structure of (+)-methyl (E)-3-[(2S,4S,5R)-2-amino-5-hy­droxy­meth­yl-2-tri­chloro­methyl-1,3-dioxolan-4-yl]-2-methyl­prop-2-enoate

    PubMed Central

    Oishi, Takeshi; Yasushima, Daichi; Yuasa, Kihiro; Sato, Takaaki; Chida, Noritaka

    2016-01-01

    In the title compound, C10H14Cl3NO5, the five-membered dioxolane ring adopts an envelope conformation. The C atom at the flap, which is bonded to the hy­droxy­methyl substituent, deviates from the mean plane of other ring atoms by 0.357 (5) Å. There are two intra­molecular hydrogen bonds (O—H⋯N and N—H⋯O) between the hy­droxy and amino groups, so that O- and N-bound H atoms involved in these hydrogen bonds are each disordered with equal occupancies of 0.50. The methyl 2-methyl­prop-2-enoate substituent also shows a disordered structure over two sets of sites with refined occupancies of 0.482 (5) and 0.518 (5). In the crystal, mol­ecules are connected into a dimer by an O—H⋯O hydrogen bond. The dimers are further linked by N—H⋯O, C—H⋯N and C—H⋯O inter­actions, extending a sheet structure parallel to (01). PMID:27006804

  17. High-resolution SO2 isotopologue spectra as evidence for sulfur MIF due to SO2 self-shielding

    NASA Astrophysics Data System (ADS)

    Lyons, J. R.; Stark, G.; Blackie, D.; Pickering, J. C.

    2009-12-01

    It is well known that photolysis of some gas-phase molecules can lead to isotopic mass-independent fractionation (MIF). Several mechanisms for photolytic MIF have been proposed including 1) self-shielding during photon absorption, 2) variations in band oscillator strengths, 3) hyperfine effects, and 4) resonant curve crossing. Self-shielding, a result of line saturation in molecules with line-type absorption spectra, is observed (and predicted) in CO and N2, both of which undergo predissociation. Here, we focus on the role of self-shielding in SO2, also a predissociating molecule. Photolysis of atmospheric SO2 is believed to be the source of sulfur isotope MIF measured in early Earth sedimentary rocks (Farquhar et al. 2000). Quantitative evaluation of this hypothesis requires accurate and high-resolution absorption cross section data. We have completed 1 cm-1 resolution measurements of 32SO2, 33SO2 and 34SO2 isotopologues using a Fourier transform spectrometer (FTS) at Imperial College (IC). A detailed description of the FTS measurements will be presented by D. Blackie et al. (this meeting). Here, we present a brief overview of the data, comparison with recently published lower resolution cross section data of Danielachet et al. (2008), and interpretation via atmospheric modeling. FTS measurements were obtained at 3 pressures (0.1, 0.2 and 0.4 torr) on pure xSO2 gas (x = 32, 33 or 34) from 222 to 188 nm. Spectra were coadded to improve S/N. Visual comparison of our spectra with the lower resolution (~ 20 cm-1) spectra of Danielache et al. (2008) reveals good overall agreement for all 3 isotopologues, although the lower resolution data is unable to resolve the dense rotational structure. However, radiative transfer calculations utilizing the two sets of cross section data in a 1-D atmospheric chemistry code (assuming 10 ppb SO2) yield very different photolytic isotope fractionations. The IC cross sections yield increasing δ34S, δ33S and Δ33S values for

  18. Variability of sulphur isotope ratios in pyrite and dissolved sulphate in granitoid fractures down to 1 km depth - Evidence for widespread activity of sulphur reducing bacteria

    NASA Astrophysics Data System (ADS)

    Drake, Henrik; Åström, Mats E.; Tullborg, Eva-Lena; Whitehouse, Martin; Fallick, Anthony E.

    2013-02-01

    higher δ34S values of the dissolved source SO42- caused by ongoing bacterial sulphate reduction in fractures with low-flow or stagnant waters. The measured groundwater had δ34SSO4 values of +9‰ to +37‰, with the highest values associated with low sulphate concentrations. These values are overall, and especially in the sulphate-poor waters down to -400 m, somewhat higher than the anticipated initial values, and can thus, like for the 34S-enriched pyrites, be explained by a Rayleigh distillation process driven by microbial sulphate reduction. An intriguing feature was that the δ34SSO4 values of the groundwater were in no case reaching up to the values required to produce biogenic pyrite with δ34S values of +40‰ to +91‰. To explain this feature, we suggest that groundwater in low-flow fractures with near-stagnant water (carrying sulphate and pyrite with high δ34S) is masked by high-flow parts of the fracture system carrying groundwater that often contains sulphate in abundance and considerably less fractionated with respect to 34S and 32S. In order to gain detailed knowledge of chemical processes and patterns in groundwater in fractured rock, fracture-mineral investigations are a powerful tool, as we have shown here for the sulphur system.

  19. Geochemistry of pyrite from diamictites of the Hamersley Basin, Western Australia with implications for the GOE and Paleoproterozoic ice ages.

    NASA Astrophysics Data System (ADS)

    Swanner, Elizabeth; Cates, Nicole; Pecoits, Ernesto; Bekker, Andrey; Konhauser, Kurt O.; Mojzsis, Stephen J.

    2013-04-01

    Sediments of the ca. 2400 Ma Turee Creek Group of Western Australia span the oxygenation of Earth's surface resulting from the 'Great Oxidation Event' (GOE). Diamictite within the Boolgeeda Iron Formation from the Boundary Ridge section at Duck Creek Syncline have been correlated to the glaciogenic Meteorite Bore Member of the Turee Creek Group at Hardey Syncline (Martin, 1999). The Meteorite Bore Member is thought to be correlative and time-equivalent with the Paleoproterozoic glacial diamictites of North America. If diamictite units at Boundary Ridge represent worldwide Paleoproterozoic glaciations, they should record the disappearance of mass independently fractionated (MIF) sulfur. Triple S-isotope compositions for pyrites from the Boundary Ridge sections measured by in situ multi-collector ion microprobe yielded both mass-dependent and mass-independently fractionated (MIF) S isotope values (Δ33S values from -0.65 to 6.27). Trace element heterogeneities were found by measurements at multiple spatial scales within rounded pyrites in the Boundary Ridge section, signifying multiple generations of pyrite from sulfur processed in an anoxic atmosphere. S-isotope data from pyrite in the Boundary Ridge diamictites analyzed in this study and previous work (Williford et al., 2011) define multiple δ34S vs. δ33S arrays, linked to a source of detrital pyrite from the overlying Hamersley and Fortescue groups. Authigenic pyrite in an overlying shale unit from Boundary Ridge plot along the terrestrial fractionation line but retain positive MIF-S and detrital pyrite, results that are incompatible with a correlation to North American Paleoproterozoic glacially-influenced successions where the MIF-S signal permanently disappears. The diamictites at the Duck Creek Syncline are older than the Meteorite Bore Member because of their stratigraphic position within the Boolgeeda Iron Formation underlying the Turee Creek Group, which is separated from the Meteorite Bore Member by

  20. Effect of intermittent blood volume fluctuation of light resistance exercise after ingestion of the high-protein snacks on plasma branched-chain amino acid concentrations in young adults.

    PubMed

    Kato, Yushi; Numao, Shigeharu; Miyauchi, Ryoko; Suzuki, Masashige

    2010-01-01

    The study investigated exercise patterns resulting in the more efficient promotion of amino acid utilization. High-protein snacks (HPS; 15 g protein, 18 g sugar) were ingested by 8 young adult subjects 3 h after the basal meal ingestion. Sixty minutes after the HPS ingestion, the subjects performed arm flex/extend exercises for 15 min. The difference between 2 exercise patterns was compared. Pattern 1: High-number long-interval (HL) arm flex/extend (3+3 s) exercise; the HL group performed 9 sets of 15 exercises with a 10 s interval between sets. Pattern 2: Low-number short-interval (LS) arm flex/extend (3+3 s) exercise; the LS group performed 27 sets of 5 exercises with a 3-4 s interval between sets (135 exercises during 15 min, respectively). The plasma branched-chain amino acid (BCAA) concentrations were measured before the HPS ingestion, before the exercise, and 60 and 90 min after the HPS ingestion. The plasma BCAA concentrations increased significantly after the HPS ingestion. In the HL group, BCAA concentration increased consistently during the period and 60 to 90 min after the HPS ingestion. During the same period in the LS group the BCAA concentration stopped increasing. After HPS ingestion, a significantly greater suppressive effect on plasma BCAA concentration was seen in the LS group compared to the HL group. Results confirmed that the intermittent blood volume fluctuation in muscle tissue during the exercise pattern performed by the LS group had an effect on the utilization of nutritional components (BCAA, glucose) from the blood, and showed the possibility that the group where the blood volume in the muscle tissue increased/lowered with higher frequency was a more effective exercise pattern for nutrient utilization. PMID:20924148

  1. SO2 photoexcitation mechanism links mass-independent sulfur isotopic fractionation in cryospheric sulfate to climate impacting volcanism

    PubMed Central

    Hattori, Shohei; Schmidt, Johan A.; Johnson, Matthew S.; Danielache, Sebastian O.; Yamada, Akinori; Ueno, Yuichiro; Yoshida, Naohiro

    2013-01-01

    Natural climate variation, such as that caused by volcanoes, is the basis for identifying anthropogenic climate change. However, knowledge of the history of volcanic activity is inadequate, particularly concerning the explosivity of specific events. Some material is deposited in ice cores, but the concentration of glacial sulfate does not distinguish between tropospheric and stratospheric eruptions. Stable sulfur isotope abundances contain additional information, and recent studies show a correlation between volcanic plumes that reach the stratosphere and mass-independent anomalies in sulfur isotopes in glacial sulfate. We describe a mechanism, photoexcitation of SO2, that links the two, yielding a useful metric of the explosivity of historic volcanic events. A plume model of S(IV) to S(VI) conversion was constructed including photochemistry, entrainment of background air, and sulfate deposition. Isotopologue-specific photoexcitation rates were calculated based on the UV absorption cross-sections of 32SO2, 33SO2, 34SO2, and 36SO2 from 250 to 320 nm. The model shows that UV photoexcitation is enhanced with altitude, whereas mass-dependent oxidation, such as SO2 + OH, is suppressed by in situ plume chemistry, allowing the production and preservation of a mass-independent sulfur isotope anomaly in the sulfate product. The model accounts for the amplitude, phases, and time development of Δ33S34S and Δ36S/Δ33S found in glacial samples. We are able to identify the process controlling mass-independent sulfur isotope anomalies in the modern atmosphere. This mechanism is the basis of identifying the magnitude of historic volcanic events. PMID:23417298

  2. SO2 photoexcitation mechanism links mass-independent sulfur isotopic fractionation in cryospheric sulfate to climate impacting volcanism.

    PubMed

    Hattori, Shohei; Schmidt, Johan A; Johnson, Matthew S; Danielache, Sebastian O; Yamada, Akinori; Ueno, Yuichiro; Yoshida, Naohiro

    2013-10-29

    Natural climate variation, such as that caused by volcanoes, is the basis for identifying anthropogenic climate change. However, knowledge of the history of volcanic activity is inadequate, particularly concerning the explosivity of specific events. Some material is deposited in ice cores, but the concentration of glacial sulfate does not distinguish between tropospheric and stratospheric eruptions. Stable sulfur isotope abundances contain additional information, and recent studies show a correlation between volcanic plumes that reach the stratosphere and mass-independent anomalies in sulfur isotopes in glacial sulfate. We describe a mechanism, photoexcitation of SO2, that links the two, yielding a useful metric of the explosivity of historic volcanic events. A plume model of S(IV) to S(VI) conversion was constructed including photochemistry, entrainment of background air, and sulfate deposition. Isotopologue-specific photoexcitation rates were calculated based on the UV absorption cross-sections of (32)SO2, (33)SO2, (34)SO2, and (36)SO2 from 250 to 320 nm. The model shows that UV photoexcitation is enhanced with altitude, whereas mass-dependent oxidation, such as SO2 + OH, is suppressed by in situ plume chemistry, allowing the production and preservation of a mass-independent sulfur isotope anomaly in the sulfate product. The model accounts for the amplitude, phases, and time development of Δ(33)S/δ(34)S and Δ(36)S/Δ(33)S found in glacial samples. We are able to identify the process controlling mass-independent sulfur isotope anomalies in the modern atmosphere. This mechanism is the basis of identifying the magnitude of historic volcanic events. PMID:23417298

  3. Temperament, age and weather predict social interaction in the sheep flock.

    PubMed

    Doyle, Rebecca E; Broster, John C; Barnes, Kirsty; Browne, William J

    2016-10-01

    The aim of the current study was to investigate the social relationships between individual sheep, and factors that influence this, through the novel application of the statistical multiple membership multiple classification (MMMC) model. In study one 49 ewes (ranging between 1 and 8 years old) were fitted with data loggers, which recorded when pairs of sheep were within 4m or less of each other, within a social group, for a total of 6days. In study two proximity data were collected from 45 ewes over 17days, as were measures of ewe temperament, weight and weather. In study 1 age difference significantly influenced daily contact time, with sheep of the same age spending an average of 20min 43s together per day, whereas pairs with the greatest difference in age spent 16min 33s together. Maximum daily temperature also significantly affected contact time, being longer on hotter days (34min 40s hottest day vs. 18min 17s coolest day), as did precipitation (29min 33s wettest day vs. 10min 32s no rain). Vocalisation in isolation, as a measure of temperament, also affected contacts, with sheep with the same frequency of vocalisations spending more time together (27min 16s) than those with the greatest difference in vocalisations (19min 36s). Sheep behaviour in the isolation box test (IBT) was also correlated over time, but vocalisations and movement were not correlated. Influences of age, temperature and rain on social contact are all well-established and so indicate that MMMC modelling is a useful way to analyse social structures of the flock. While it has been demonstrated that personality factors affect social relationships in non-human animals, the finding that vocalisation in isolation influences pair social contact in sheep is a novel one. PMID:27542918

  4. Stable Isotope Phenotyping via Cluster Analysis of NanoSIMS Data As a Method for Characterizing Distinct Microbial Ecophysiologies and Sulfur-Cycling in the Environment

    PubMed Central

    Dawson, Katherine S.; Scheller, Silvan; Dillon, Jesse G.; Orphan, Victoria J.

    2016-01-01

    Stable isotope probing (SIP) is a valuable tool for gaining insights into ecophysiology and biogeochemical cycling of environmental microbial communities by tracking isotopically labeled compounds into cellular macromolecules as well as into byproducts of respiration. SIP, in conjunction with nanoscale secondary ion mass spectrometry (NanoSIMS), allows for the visualization of isotope incorporation at the single cell level. In this manner, both active cells within a diverse population as well as heterogeneity in metabolism within a homogeneous population can be observed. The ecophysiological implications of these single cell stable isotope measurements are often limited to the taxonomic resolution of paired fluorescence in situ hybridization (FISH) microscopy. Here we introduce a taxonomy-independent method using multi-isotope SIP and NanoSIMS for identifying and grouping phenotypically similar microbial cells by their chemical and isotopic fingerprint. This method was applied to SIP experiments in a sulfur-cycling biofilm collected from sulfidic intertidal vents amended with 13C-acetate, 15N-ammonium, and 33S-sulfate. Using a cluster analysis technique based on fuzzy c-means to group cells according to their isotope (13C/12C, 15N/14N, and 33S/32S) and elemental ratio (C/CN and S/CN) profiles, our analysis partitioned ~2200 cellular regions of interest (ROIs) into five distinct groups. These isotope phenotype groupings are reflective of the variation in labeled substrate uptake by cells in a multispecies metabolic network dominated by Gamma- and Deltaproteobacteria. Populations independently grouped by isotope phenotype were subsequently compared with paired FISH data, demonstrating a single coherent deltaproteobacterial cluster and multiple gammaproteobacterial groups, highlighting the distinct ecophysiologies of spatially-associated microbes within the sulfur-cycling biofilm from White Point Beach, CA. PMID:27303371

  5. Stable Isotope Phenotyping via Cluster Analysis of NanoSIMS Data As a Method for Characterizing Distinct Microbial Ecophysiologies and Sulfur-Cycling in the Environment.

    PubMed

    Dawson, Katherine S; Scheller, Silvan; Dillon, Jesse G; Orphan, Victoria J

    2016-01-01

    Stable isotope probing (SIP) is a valuable tool for gaining insights into ecophysiology and biogeochemical cycling of environmental microbial communities by tracking isotopically labeled compounds into cellular macromolecules as well as into byproducts of respiration. SIP, in conjunction with nanoscale secondary ion mass spectrometry (NanoSIMS), allows for the visualization of isotope incorporation at the single cell level. In this manner, both active cells within a diverse population as well as heterogeneity in metabolism within a homogeneous population can be observed. The ecophysiological implications of these single cell stable isotope measurements are often limited to the taxonomic resolution of paired fluorescence in situ hybridization (FISH) microscopy. Here we introduce a taxonomy-independent method using multi-isotope SIP and NanoSIMS for identifying and grouping phenotypically similar microbial cells by their chemical and isotopic fingerprint. This method was applied to SIP experiments in a sulfur-cycling biofilm collected from sulfidic intertidal vents amended with (13)C-acetate, (15)N-ammonium, and (33)S-sulfate. Using a cluster analysis technique based on fuzzy c-means to group cells according to their isotope ((13)C/(12)C, (15)N/(14)N, and (33)S/(32)S) and elemental ratio (C/CN and S/CN) profiles, our analysis partitioned ~2200 cellular regions of interest (ROIs) into five distinct groups. These isotope phenotype groupings are reflective of the variation in labeled substrate uptake by cells in a multispecies metabolic network dominated by Gamma- and Deltaproteobacteria. Populations independently grouped by isotope phenotype were subsequently compared with paired FISH data, demonstrating a single coherent deltaproteobacterial cluster and multiple gammaproteobacterial groups, highlighting the distinct ecophysiologies of spatially-associated microbes within the sulfur-cycling biofilm from White Point Beach, CA. PMID:27303371

  6. Stable isotope biogeochemistry of the sulfur cycle in modern marine sediments: I. Seasonal dynamics in a temperate intertidal sandy surface sediment.

    PubMed

    Böttcher, Michael; Hespenheide, Britta; Brumsack, Hans-Jürgen; Bosselmann, Katja

    2004-12-01

    A biogeochemical and stable isotope geochemical study was carried out in surface sediments of an organic-matter poor temperate intertidal sandy surface sediment (German Wadden Sea of the North Sea) to investigate the activity of sulfate-reducing bacteria and the dynamics of the vertical partitioning of sedimentary sulfur, iron, and manganese species in relation to the availability of total organic carbon (TOC) and mud contents. The contents and stable isotopic compositions ((34)S/(32)S) of total reduced inorganic sulfur species (TRIS) and dissolved sulfate were measured. Maximum oxygen penetration depths were estimated from the onset of a blackening of the sediments due to FeS accumulation and ranged from 5 to 10 mm below surface (mmbsf). A zone of relatively moderate relative organic-matter enrichment was found between 5 and 20 mmbsf leading to enhanced activities of sulfate-reducing bacteria with sulfate-reduction rates (SRR) up to 350 nmol cm(-3) d(-1). Below this zone, microbial SRR dropped significantly. Depth integrated SRR seem to depend not only on temperature but also on the availability of reactive organic matter. The sulfur-isotopic composition of TRIS was depleted in (34)S by 33-40 per thousand with respect to coexisting dissolved sulfate (constant at about +21 per thousand vs. Vienna-Canyon Diablo Troilite (V-CDT)). Since sulfate reduction is not limited by dissolved sulfate (open system), depth variations of the isotopic composition of TRIS reflect changes in overall isotope effect due to superimposed microbial and abiotic reactions. Most of the solid-phase iron and manganese was bonded to (non-reactive) heavy minerals. However, a layer of reactive Fe(III) and Mn(IV) oxi(hydroxi)des was found in the uppermost sediment section due to re-oxidation of dissolved Fe(II) and Mn(II) species at the sediment-water interface. Metal cycling below the surface is at least partially coupled to intense sulfur cycling. PMID:15621745

  7. A strategy for fast screening and identification of sulfur derivatives in medicinal Pueraria species based on the fine isotopic pattern filtering method using ultra-high-resolution mass spectrometry.

    PubMed

    Yang, Min; Zhou, Zhe; Guo, De-an

    2015-09-24

    Sulfurous compounds are commonly present in plants, fungi, and animals. Most of them were reported to possess various bioactivities. Isotopic pattern filter (IPF) is a powerful tool for screening compounds with distinct isotope pattern. Over the past decades, the IPF was used mainly to study Cl- and Br-containing compounds. To our knowledge, the algorithm was scarcely used to screen S-containing compounds, especially when combined with chromatography analyses, because the (34)S isotopic ion is drastically affected by (13)C2 and (18)O. Thus, we present a new method for a fine isotopic pattern filter (FIPF) based on the separated M + 2 ions ((12)C(x)(1)H(y)(16)O(z)(32)S(13)C2(18)O, (12)C(x+2)(1)H(y)(16)O(z+1)(34)S, tentatively named M + 2OC and M + 2S) with an ultra-high-resolution mass (100,000 FWHM @ 400 m/z) to screen sulfur derivatives in traditional Chinese medicines (TCM).This finer algorithm operates through convenient filters, including an accurate mass shift of M + 2OC and M + 2S from M and their relative intensity compared to M. The method was validated at various mass resolutions, mass accuracies, and screening thresholds of flexible elemental compositions. Using the established FIPF method, twelve S-derivatives were found in the popular medicinal used Pueraria species, and 9 of them were tentatively identified by high-resolution multiple stage mass spectrometry (HRMS(n)). The compounds were used to evaluate the sulfurous compounds' situation in commercially purchased Pueraria products. The strategy presented here provides a promising application of the IPF method in a new field. PMID:26423627

  8. Mass independent fractionation of sulfur isotopes during thermochemical reduction of native sulfur, sulfite and sulfate by amino acids

    NASA Astrophysics Data System (ADS)

    Watanabe, Y.; Naraoka, H.; Ohmoto, H.

    2006-05-01

    Mass independent fractionation of sulfur isotopes (MIF-S) is recognized when the Δ33S value (= δ33S-0.515xδ34S) of a sample falls outside the range of 0±0.2 permil and the 33-34θ value (= ln33α/ ln34α) lies outside the range of 0.515±.005 (Farquhar and Wing, 2003). Previous investigators have concluded that the only mechanisms to create MIF-S are photochemical reactions between sulfur-bearing gases (SO2, H2S) and UV. Based on comparisons of the geochemical characteristics of Archean sedimentary rocks between those with large MIF-S values (e.g., the 2.5 Ga McRae and 2.7 Ga Jeerinah shales) and those with no (or very small) MIF- S values (e.g., 2.76 Ga Hardey shales and 2.92 Ga Mosquito Creek shales), we have developed a hypothesis that MIF-S in sedimentary rocks may have been created by reactions among organic-rich sediments, sulfur- bearing solid compounds, and sulfur-bearing hydrothermal fluids at T = 100-200°C during the early diagenetic stage of sediments. Most abundant organic compounds in immature sediments are amino acids. For these reasons, we have conducted series of laboratory experiments to investigate sulfur isotope fractionations during reactions between a variety of amino acids (alanine, glycine, hystidine, etc.) and native sulfur, sodium sulfite or sodium sulfate at 150-200°C. Previous researchers used a variety of organic compounds (sugars, methane, xylene, etc) and/or ferrous- bearing minerals to investigate non-bacterial sulfate reduction, but they failed to demonstrate thermochemical sulfate reduction at temperatures below 230°C. However, we were able to reduce sulfate (S6+), as well as sulfite (S4+) and native sulfur (S0), to hydrogen sulfide (S2-) even at 150°C using simple and common amino acids (e.g., alanine and glycine). The reduction rates generally decreased: (a) from native sulfur, to sulfite, and to sulfate; (b) from simple amino acids to more complex amino acids (e.g., histidine); and (c) with decreasing temperatures. The

  9. The Bolivian and Maipo Oroclines: Two first scale structural features of the Central Andes

    NASA Astrophysics Data System (ADS)

    Arriagada, C. A.

    2013-05-01

    response to oblique convergence or to deformation of the Andean Cordillera since Early Oligocene - Middle Miocene times. Nevertheless, near 34S paleomagnetic results from the El Teniente copper-molybdenum porphyry deposit show no evidence for rotations during the last 5 Ma. To explain de origin of the Maipo Orocline, we propose a coupled Bolivian Orocline - Juan Fernández Ridge (JFR) model, where a far-field component of clockwise rotation related to the formation of the Bolivian Orocline was first acquired by the forearc between 31 and 33S. The same area was later rotated by a slight counterclockwise component related to the subduction of the JFR over the last 10 Ma. South of 33S the clockwise rotations related to the Bolivian Orocline component were amplified by the subduction of the JFR.t;

  10. A new occurrence of ambient inclusion trails from the ~1900-million-year-old Gunflint Formation, Ontario: nanocharacterization and testing of potential formation mechanisms.

    PubMed

    Wacey, D; Saunders, M; Kong, C; Kilburn, M R

    2016-09-01

    Ambient inclusion trails (AITs) are tubular microstructures thought to form when a microscopic mineral crystal is propelled through a fine-grained rock matrix. Here, we report a new occurrence of AITs from a fossilized microbial mat within the 1878-Ma Gunflint Formation, at Current River, Ontario. The AITs are 1-15 μm in diameter, have pyrite as the propelled crystal, are infilled with chlorite and have been propelled through a microquartz (chert) or chlorite matrix. AITs most commonly originate at the boundary between pyrite- and chlorite-rich laminae and chert-filled fenestrae, with pyrite crystals propelled into the fenestrae. A subset of AITs originate within the fenestrae, rooted either within the chert or within patches of chlorite. Sulphur isotope data ((34) S/(32) S) obtained in situ from AIT pyrite have a δ(34) S of -8.5 to +8.0 ‰, indicating a maximum of ~30 ‰ fractionation from Palaeoproterozoic seawater sulphate (δ(34) S ≈ +20 ‰). Organic carbon is common both at the outer margins of the fenestrae and in patches of chlorite where most AITs originate, and can be found in smaller quantities further along some AITs towards the terminal pyrite grain. We infer that pyrite crystals now found within the AITs formed via the action of heterotrophic sulphate-reducing bacteria during early diagenesis within the microbial mat, as pore waters were becoming depleted in seawater sulphate. Gases derived from this process such as CO2 and H2 S were partially trapped within the microbial mat, helping produce birds-eye fenestrae, while rapid microquartz precipitation closed porosity. We propose that propulsion of the pyrite crystals to form AITs was driven by two complementary mechanisms during burial and low-grade metamorphism: firstly, thermal decomposition of residual organic material providing CO2 , and potentially CH4 , as propulsive gases, plus organic acids to locally dissolve the microquartz matrix; and secondly, reactions involving clay minerals that

  11. Stable isotope (O, H, S) relationships in Tertiary basalts and their mantle xenoliths from the Northern Hessian Depression, W.-Germany

    NASA Astrophysics Data System (ADS)

    Harmon, R. S.; Hoefs, J.; Wedepohl, K. H.

    1987-03-01

    18O/16O, 34S/32S, and D/H ratios as well as vacuum-fusion H2O+ contents were measured for late Tertiary volcanic basaltic rocks ranging in composition from quartz tholeiites and alkali olivine basalts to melilite-bearing olivine nephelinites and for peridotite xenoliths from the Northern Hessian Depression of W.-Germany. Measured Oisotope ratios in both basalts and peridotites were corrected for variable degree of post-eruption, secondary alteration. The ranges and means of corrected δ 18O values (‰ SMOW) for the North Hessian lavas and peridotites are: (i) 8 tholeiites: ca. +6.1 to +7.3 ( ¯x=+6.6), (ii) 21 alkali olivine basalts: ca. +5.4 to +7.6 ( ¯x=+6.5), (iii) 19 nepheline basanites, limburgites, and olivine nephelinites: ca. +5.3 to +8.0 ( ¯x=+6.6), and (iv) 23 peridotites: +5.1 to 7.0 ( ¯x+6.0). The δ 34S values (‰ CDT) for the tholeiites range from -0.6 to +1.4 ( ¯x=-0.03) and for the alkali basalts range from +0.9 to +8.6 ( ¯x=+2.5). The approximate δD value (‰ SMOW) of the pristine basalts and peridotites is estimated to have been ca. -90‰ The quartz tholeiites appear to have had a different genetic history than the alkali basalts. Supported by chemical evidence, the 18O and 87Sr enrichment observed in the tholeiites suggests low crustal contamination of parental olivine tholeiite melts, derived from a depleted mantle source. The contamination by crustal partial melts may have occurred in granulitic lower crust during differentiation. By contrast the high δ 18O and δ 34S values observed for the alkali basalts and peridotites are best explained in terms of metasomatic alteration of the mantle source region by fluids enriched in 18O, K, and incompatible trace elements prior to partial melting. The δ 18O-K relationships for the peridotites indicate that the mantle beneath the Northern Hessian Depression has had a complex stable isotope history involving at least two distinct metasomatic events. The earlier event involved a CO2-rich fluid

  12. Computational and Observational Studies of Interstellar Thioformaldehyde Masers

    NASA Astrophysics Data System (ADS)

    Simpson, Lisa; Hoffman, I. M.

    2013-06-01

    Interstellar spectroscopy of thioformaldehyde (H2CS) holds considerable promise because of the close relationship between the H2CS molecule and the well-studied formaldehyde (H2CO) molecule. In particular, the well-known J(Ka,Kc) = 1(1,0) to 1(1,1) transition of H2CO at 6 cm (4.8 GHz) has an analogous H2CS transition at 1046 MHz. However, the 1046-MHz line of H2CS has never been detected astronomically. We present here a summary of: (1) a computational investigation of H2CS level populations related to known H2CO 6-cm masers, and (2) an observational campaign of four isotopologues of H2CS. Maser emission from H2CO has been observed at 6 cm for which Boland and de Jong (1981) have developed a pump model. We have extended this model to H2CS and we present preliminary calculations for a 1046-MHz maser. We intend to develop a quantitative tool for interpreting H2CS observations toward Galactic and extragalactic locations of H2CO maser emission by constructing a radiative-transfer maser model for H2CS. Thioformaldehyde has been detected in a few Galactic sources via J>1 transitions. However, interpretation of these results has two outstanding problems: the H2CS/H2CO abundances do not agree with known sulfur-to-oxygen ratios nor do the J>1 populations have the expected Boltzmann relationship to the J=1 states. A detection of the 1046-MHz transition of H2CS with J=1 would alleviate many of the ambiguities in the interpretation of existing observational results. We describe our forthcoming experiment to search in a Galactic star-forming region for thermal and nonthermal emission and absorption from four thioformaldehyde isotopologues: H2(12C)(32S), H2(13C)(32S), H2(12C)(34S), and D2(12C)(32S). Taken together, both parts of this research effort will provide valuable and novel constraints on H2CS and H2CO. New observations of H2CS isotopologues will yield new measurements of deuterium-to-hydrogen and sulfur-to-oxygen ratios in star-forming environments. Also, the application

  13. Sulfur Isotope Composition of Volcanic Sulfate in Polar Ice Cores (Invited)

    NASA Astrophysics Data System (ADS)

    Cole-Dai, J.; Savarino, J.; Thiemens, M. H.

    2011-12-01

    Explosive volcanic eruptions often emit copious amounts of sulfur gases into the atmosphere. Similar to that of anthropogenic aerosols, volcanic aerosols can influence climate by altering the atmosphere's radiative properties. Traces of sulfate aerosols from past explosive eruptions are preserved in the snow strata of polar ice sheets and can be retrieved with ice cores. We have been measuring sulfur isotope composition of volcanic sulfate in Antarctica and Greenland ice cores to investigate the kinetics of atmospheric oxidation chemistry and to determine the climatic impact of the eruptions. We have found that the chemical conversion process of volcanic sulfur dioxide into sulfuric acid and sulfate aerosols in the stratosphere proceeds through oxidation reaction pathways different from those for sulfur dioxide in the troposphere. Recent laboratory experiments and modeling efforts by other investigators support the hypothesis that short wavelength ultra-violet radiation above the stratospheric ozone layer plays a key role in the chemical conversion or oxidation and can cause mass independent fractionation (MIF) of sulfur isotopes (33S, 34S, 36S). The discovery of the sulfur MIF isotope signatures in the volcanic sulfate offers a unique and dependable way to distinguish the signals of large, stratospheric eruptions in the ice core volcanic records from those of eruptions with little or no climate impact. Identification of the climate-impacting eruptions helps to improve our understanding of the volcano-climate connection.

  14. Sulfur Isotope Composition of Volcanic Sulfate in Polar Ice Cores (Invited)

    NASA Astrophysics Data System (ADS)

    Cole-Dai, J.; Savarino, J.; Thiemens, M. H.

    2013-12-01

    Explosive volcanic eruptions often emit copious amounts of sulfur gases into the atmosphere. Similar to that of anthropogenic aerosols, volcanic aerosols can influence climate by altering the atmosphere's radiative properties. Traces of sulfate aerosols from past explosive eruptions are preserved in the snow strata of polar ice sheets and can be retrieved with ice cores. We have been measuring sulfur isotope composition of volcanic sulfate in Antarctica and Greenland ice cores to investigate the kinetics of atmospheric oxidation chemistry and to determine the climatic impact of the eruptions. We have found that the chemical conversion process of volcanic sulfur dioxide into sulfuric acid and sulfate aerosols in the stratosphere proceeds through oxidation reaction pathways different from those for sulfur dioxide in the troposphere. Recent laboratory experiments and modeling efforts by other investigators support the hypothesis that short wavelength ultra-violet radiation above the stratospheric ozone layer plays a key role in the chemical conversion or oxidation and can cause mass independent fractionation (MIF) of sulfur isotopes (33S, 34S, 36S). The discovery of the sulfur MIF isotope signatures in the volcanic sulfate offers a unique and dependable way to distinguish the signals of large, stratospheric eruptions in the ice core volcanic records from those of eruptions with little or no climate impact. Identification of the climate-impacting eruptions helps to improve our understanding of the volcano-climate connection.

  15. Quantitative images of metals in plant tissues measured by laser ablation inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Becker, J. S.; Dietrich, R. C.; Matusch, A.; Pozebon, D.; Dressler, V. L.

    2008-11-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for quantitative imaging of toxic and essential elements in thin sections (thickness of 30 or 40 μm) of tobacco plant tissues. Two-dimensional images of Mg, Fe, Mn, Zn, Cu, Cd, Rh, Pt and Pb in leaves, shoots and roots of tobacco were produced. Sections of the plant tissues (fixed onto glass slides) were scanned by a focused beam of a Nd:YAG laser in a laser ablation chamber. The ablated material was transported with argon as carrier gas to the ICP ion source at a quadrupole ICP-MS instrument. Ion intensities of the investigated elements were measured together with 13C +, 33S + and 34S + within the entire plant tissue section. Matrix matching standards (prepared using powder of dried tobacco leaves) were used to constitute calibration curves, whereas the regression coefficient of the attained calibration curves was typically 0.99. The variability of LA-ICP-MS process, sample heterogeneity and water content in the sample were corrected by using 13C + as internal standard. Quantitative imaging of the selected elements revealed their inhomogeneous distribution in leaves, shoots and roots.

  16. From snowball earth to the cambrian explosion: the interpretative potential of the isotope record

    NASA Astrophysics Data System (ADS)

    Shields, G.

    2003-04-01

    The interval in Earth history between 750 Ma and 530 Ma represents the erratic transition between the distinctly different "Earth systems" of the Proterozoic and the Phanerozoic. Geologists have developed several indirect methods to study this key interval but perhaps none with as much wanton enthusiasm as isotope geochemistry. Here I attempt a review of the isotope record across this key transition period, with special emphasis on the interpretative role that isotopes can play in understanding events such as the "Snowball Earth" glaciations and the "Cambrian Explosion". The marine isotope record reveals the Proterozoic-Phanerozoic transition to have been a unique period in Earth history with first-order features in all three of the major isotope proxies: 87Sr/86Sr, 34S/32S and 13C/12C ratios. Seawater 87Sr/86Sr, increased sharply between about 900 Ma and 500 Ma from 0.704 to 0.709, the largest rise ever. Although attributed to increasing rates of continental erosion, this remains only the most plausible explanation because few aspects of the rise have been satisfactorily linked to particular tectonic events. Much of the uncertainty surrounding the Proterozoic 87Sr/86Sr record is due to poor age dating and discrepancies in stratigraphic correlation schemes, which together with diagenetic alteration have led to the current inability to realise the potential of the 87Sr/86Sr record for global stratigraphic correlation. Carbon isotopes have played a key role in recent palaeoenvironmental interpretations of the Proterozoic-Phanerozoic transition, most of which have already been discarded or merely forgotten. Nevertheless, it is clear that the extraordinary δ13C values of the later Neoproterozoic (and the earliest Cambrian) demand extraordinary explanations, for which there is still much scope for future invention. Carbon isotopes may also play an important supporting role in correlation, however, the role that δ13C may play in global stratigraphic correlation has

  17. Os, Nd, O and S isotope constraints on country rock contamination in the conduit-related Eagle Cu-Ni-(PGE) deposit, Midcontinent Rift System, Upper Michigan

    NASA Astrophysics Data System (ADS)

    Ding, Xin; Ripley, Edward M.; Shirey, Steven B.; Li, Chusi

    2012-07-01

    The Eagle Cu-Ni-(PGE) deposit is hosted by mafic to ultramafic intrusive rocks associated with the Marquette-Baraga dike swarm in northern Michigan. Sulfide mineralization formed in a conduit system during early stages in the development of the ∼1.1 Ga Midcontinent Rift System. The conduit environment represents a prime location for melt-rock interaction. In order to better assess the extent of country rock contamination in the Eagle system, a combined trace element, Nd, Os, O and S isotope study of country rocks, sulfide-bearing igneous rocks and massive sulfide was undertaken. Both the Eagle and the weakly mineralized East Eagle intrusion show trace element patterns that are similar to those of picritic basalts that formed during early stages of rift development. The trace element, Os, Nd, and O isotopic values of the igneous rocks are consistent with <5% of bulk contamination by Paleoproterozoic and Archean country rocks. Both the Re-Os and Sm-Nd system provide isochrons that are in agreement with the 1107 Ma U-Pb baddeleyite age of the intrusive rocks. Calculated γOs(1100) and εNd(1100) values for the magmas are +34 and -2. δ18O values of pyroxene in feldspathic pyroxenite range from 6.5‰ to 6.6‰ and provide the only indication that bulk contamination may locally have exceeded 20%. Sulfur isotopic values of disseminated and massive sulfide in the Eagle intrusion range from 0.3‰ to 4.6‰. The δ34S values are much lower than those that characterize most of the country rocks, but could still be indicative of a contribution of S from country rocks of up to ∼50%. Δ33S values of the disseminated and massive sulfides range from -0.10‰ to 0.09‰ indicating a source in Paleoproterozoic country rocks. Semi-massive sulfide in the Eagle deposit has δ34S values between 2.2‰ and 5.3‰, and Δ33S values show a broad range between -0.86‰ and 0.86‰ indicating a major contribution from an Archean source. Isotopic data from the Eagle deposit strongly

  18. Depth profiling sulphur in bulk CdTe and {CdTe}/{CdS} thin film heterojunctions

    NASA Astrophysics Data System (ADS)

    Lane, D. W.; Conibeer, G. J.; Romani, S.; Healy, M. J. F.; Rogers, K. D.

    1998-03-01

    Polycrystalline CdTeCdS heterojunction solar cells are a possible candidate for the low cost, high efficiency conversion of solar energy. The formation of an intermediate CdS xTe 1- x layer during a high temperature annealing stage is believed to increase optical absorption and decrease cell efficiency. S diffusion in single crystal CdTe has been investigated by NRA using the 32S (d,p o) 33S nuclear reaction, at a deuteron energy of 2 MeV. Details of the NRA depth profiling procedure are given, which was found to be relatively straightforward and suitable for use on a small Van de Graaff accelerator. The resulting diffusion parameters are compared to those obtained by SIMS using a Cs + primary ion beam, examining negative secondary ions. The diffusion coefficients were found to be 1.1 × 10 -15cm 2 s -1 at 450°C and ˜8 × 10 -15cm -1 s at 550°C. S diffusion in thin films was also investigated by 2 MeV 4He + RBS on annealed polycrystalline CdSCdTe multilayers.

  19. (SO2)-S-34-O-16: High-resolution analysis of the (030),(101), (111), (002) and (201) vibrational states; determination of equilibrium rotational constants for sulfur dioxide and anharmonic vibrational constants

    SciTech Connect

    Lafferty, Walter; Flaud, Jean-marie; Ngom, El Hadji A.; Sams, Robert L.

    2009-01-02

    High resolution Fourier transform spectra of a sample of sulfur dioxide, enriched in 34S (95.3%). were completely analyzed leading to a large set of assigned lines. The experimental levels derived from this set of transitions were fit to within their experimental uncertainties using Watson-type Hamiltonians. Precise band centers, rotational and centrifugal distortion constants were determined. The following band centers in cm-1 were obtained: ν0(3ν2)=1538.720198(11), ν0(ν1+ν3)=2475.828004(29), ν0(ν1+ν2+ν3)=2982.118600(20), ν0(2ν3)=2679.800919(35), and ν0(2ν1+ν3)=3598.773915(38). The rotational constants obtained in this work have been fit together with the rotational constants of lower lying vibrational states [ W.J. Lafferty, J.-M. Flaud, R.L. Sams and EL Hadjiabib, in press] to obtain equilibrium constants as well as vibration-rotation constants. These equilibrium constants have been fit together with those of 32S16O2 [J.-M. Flaud and W.J. Lafferty, J. Mol. Spectrosc. 16 (1993) 396-402] leading to an improved equilibrium structure. Finally the observed band centers have been fit to obtain anharmonic rotational constants.

  20. Sulfuric acid speleogenesis of Carlsbad Cavern and its relationship to hydrocarbons, Delaware basin, New Mexico and Texas

    SciTech Connect

    Hill, C.A. )

    1990-11-01

    Sulfur-isotope data and pH-dependence of the mineral endellite support the hypothesis that Carlsbad Cavern and other caves in the Guadalupe Mountains were dissolved primarily by sulfuric acid rather than by carbonic acid. Floor gypsum deposits up to 10 m thick and native sulfur in the caves are significantly enriched in {sup 32}S; {delta}{sup 34}S values as low as {minus}25.8 {per thousand} (CDT) indicate that the cave sulfur and gypsum are the end products of microbial reactions associated with hydrocarbons. A model for a genetic connection between hydrocarbons in the basin and caves in the Guadalupe Mountains is proposed. As the Guadalupe Mountains were uplifted during the late Pliocene-Pleistocene, oil and gas moved updip in the basin. The gas reacted with sulfate anions derived from dissolution of the Castile anhydrite to form H{sub 2}S, CO{sub 2}, and castile limestone. The hydrogen sulfide rose into the Capitan reef along joints, forereef carbonate beds, or Bell Canyon siliciclastic beds and there reacted with oxygenated groundwater to form sulfuric acid and Carlsbad Cavern. A sulfuric-acid mode of dissolution may be responsible for large-scale porosity of some Delaware basin reservoirs and for oil-field karst reservoirs in other petroleum basins of the world. 8 figs.

  1. Optical models from low-energy s-, p- and d-wave cross sections

    SciTech Connect

    Johnson, C.H.

    1984-01-01

    From transmission measurements with good resolution at low energies one can obtain data on the optical model potential (OMP) for individual partical waves by first making a multilevel analysis to isolate the partial waves and then averaging for comparison to the OMP. For each J..pi.. the averaging yields two quantities which are related to the amplitude and phase of the OMP scattering function or, alternatively, to the volume integrals of the real and imaginary potentials. Historically, the experimental average have been represented by the s- and p-wave strength functions, S/sub 0/ and S/sub 1/, and the s-wave scattering radius R'. To make full use of data from modern time-of-flight facilities such as ORELA it is necessary to re-examine the averaging procedure in order to extend it upward both in energy and neutron l-value. This averaging is discussed and applied to data on /sup 30/Si, /sup 32/S, /sup 34/S, /sup 40/Ca, /sup 60/Ni, /sup 86/Kr and /sup 208/Pb. The resulting OMP shows a systematic real potential with some indication of a parity dependence. The imaginary potential shows considerable fluctuations indicating the importance of nuclear structure at neutron eneries below 1 MeV. A coupled channel OMP is also discussed for some of the nulei. 19 references.

  2. Sulfur-containing flavors: gas phase structures of dihydro-2-methyl-3-thiophenone.

    PubMed

    Mouhib, Halima; Van, Vinh; Stahl, Wolfgang

    2013-08-01

    Dihydro-2-methyl-3-thiophenone was investigated using a combination of quantum chemical calculations and molecular beam Fourier transform microwave spectroscopy. The substance is present in coffee, roasted peanuts, and whiskey. The microwave spectrum was recorded under molecular beam conditions in the frequency range from 9 to 14 GHz. We report on the two main conformers of dihydro-2-methyl-3-thiophenone, for which highly accurate rotational constants and centrifugal distortion constants were obtained. No splittings due to internal rotation of the methyl group could be observed in the microwave spectrum. This is in agreement with the theoretical predictions of the barrier heights, which have been determined to be more than 1000 cm(-1) at the MP2/6-311++G(d,p) level of theory. In addition to the most abundant (32)S-isotopologue of the main conformer, also the (34)S-isotopologue was assigned, which occurs with a natural abundance of about 4%. Using the experimental rotational constants, different quantum chemical calculations were validated for the two observed conformers. To complete the theoretical investigation of dihydro-2-methyl-3-thiophenone, different transition states were optimized to understand the intramolecular conversion between the two conformers at the MP2/6-311++G(d,p) level. The transition states were optimized using the Berny algorithm. PMID:23815419

  3. The growth of ``black crusts'' on calcareous building stones in Palermo (Sicily): a first appraisal of anthropogenic and natural sulphur sources

    NASA Astrophysics Data System (ADS)

    Montana, Giuseppe; Randazzo, Luciana; Oddo, Ilaria A.; Valenza, Mariano

    2008-11-01

    Chemical, mineralogical and isotopic composition (34S/32S) analyses were carried out on “black crusts” developed on the old buildings of Palermo (Sicily) with the aim to distinguish between natural and anthropogenic sulphur sources. Furthermore individual samples of total suspended particulate (TSP) were collected and analysed in order to estimate the influence of air pollution on the decay process of calcareous stones in a typical southern Mediterranean coastal environment. SEM/EDS analysis, X-ray diffractometry, IR spectroscopy and liquid chromatography led to the compositional characterization of “black crusts” and airborne particulate matter in the city. Sulphur isotopic compositions of gypsum-bearing crusts showed a prevailing contribution of anthropogenic sources (vehicle exhaust and other combustion processes). Natural sulphur and/or sulphate sources (biogenic and/or sea-spray) were shown to play a secondary role. These data can be considered a starting point for the determination of the rate of growth of “black crusts” in a coastal Mediterranean urban environment like Palermo. In the future, they might be useful to local authorities for planning more efficient maintenance action in order to slow as much as possible the rate of decay of the monumental heritage of the city.

  4. No oxygen isotope exchange between water and APS-sulfate at surface temperature: Evidence from quantum chemical modeling and triple-oxygen isotope experiments

    NASA Astrophysics Data System (ADS)

    Kohl, Issaku E.; Asatryan, Rubik; Bao, Huiming

    2012-10-01

    In both laboratory experiments and natural environments where microbial dissimilatory sulfate reduction (MDSR) occurs in a closed system, the δ34S ((34S/32S)sample/(34S/32S)standard - 1) for dissolved SO42- has been found to follow a typical Rayleigh-Distillation path. In contrast, the corresponding δ18O ((18O/16O)sample/(18O/16O)standard) - 1) is seen to plateau with an apparent enrichment of between 23‰ and 29‰ relative to that of ambient water under surface conditions. This apparent steady-state in the observed difference between δ18O and δ18OO can be attributed to any of these three steps: (1) the formation of adenosine-5'-phosphosulfate (APS) from ATP and SO42-, (2) oxygen exchange between sulfite (or other downstream sulfoxy-anions) and water later in the MDSR reaction chain and its back reaction to APS and sulfate, and (3) the re-oxidation of produced H2S or precursor sulfoxy-anions to sulfate in environments containing Fe(III) or O2. This study examines the first step as a potential pathway for water oxygen incorporation into sulfate. We examined the structures and process of APS formation using B3LYP/6-31G(d,p) hybrid density functional theory, implemented in the Gaussian-03 program suite, to predict the potential for oxygen exchange. We conducted a set of in vitro, enzyme-catalyzed, APS formation experiments (with no further reduction to sulfite) to determine the degree of oxygen isotope exchange between the APS-sulfate and water. Triple-oxygen-isotope labeled water was used in the reactor solutions to monitor oxygen isotope exchange between water and APS sulfate. The formation and hydrolysis of APS were identified as potential steps for oxygen exchange with water to occur. Quantum chemical modeling indicates that the combination of sulfate with ATP has effects on bond strength and symmetry of the sulfate. However, these small effects impart little influence on the integrity of the SO42- tetrahedron due to the high activation energy required for

  5. Discovery of (1R,5S)-N-[3-Amino-1-(cyclobutylmethyl)-2,3-dioxopropyl]- 3-[2(S)-[[[(1,1-dimethylethyl)amino]carbonyl]amino]-3,3-dimethyl-1-oxobutyl]- 6,6-dimethyl-3-azabicyclo[3.1.0]hexan-2(S)-carboxamide (SCH 503034), a Selective, Potent, Orally Bioavailable Hepatitis C Virus NS3 Protease Inhibitor: A Potential Therapeutic Agent for the Treatment of Hepatitis C Infection

    SciTech Connect

    Venkatraman, Srikanth; Bogen, Stephane L.; Arasappan, Ashok; Bennett, Frank; Chen, Kevin; Jao, Edwin; Liu, Yi-Tsung; Lovey, Raymond; Hendrata, Siska; Huang, Yuhua; Pan, Weidong; Parekh, Tejal; Pinto, Patrick; Popov, Veljko; Pike, Russel; Ruan, Sumei; Santhanam, Bama; Vibulbhan, Bancha; Wu, Wanli; Yang, Weiying; Kong, Jianshe; Liang, Xiang; Wong, Jesse; Liu, Rong; Butkiewicz, Nancy; Chase, Robert; Hart, Andrea; Agrawal, Sony; Ingravallo, Paul; Pichardo, John; Kong, Rong; Baroudy, Bahige; Malcolm, Bruce; Guo, Zhuyan; Prongay, Andrew; Madison, Vincent; Broske, Lisa; Cui, Xiaoming; Cheng, Kuo-Chi; Hsieh, Yunsheng; Brisson, Jean-Marc; Prelusky, Danial; Korfmacher, Walter; White, Ronald; Bogdanowich-Knipp, Susan; Pavlovsky, Anastasia; Bradley, Prudence; Saksena, Anil K.; Ganguly, Ashit; Piwinski, John; Girijavallabhan, Viyyoor; Njoroge, F. George

    2008-06-30

    Hepatitis C virus (HCV) infection is the major cause of chronic liver disease, leading to cirrhosis and hepatocellular carcinoma, which affects more than 170 million people worldwide. Currently the only therapeutic regimens are subcutaneous interferon-{alpha} or polyethylene glycol (PEG)-interferon-{alpha} alone or in combination with oral ribavirin. Although combination therapy is reasonably successful with the majority of genotypes, its efficacy against the predominant genotype (genotype 1) is moderate at best, with only about 40% of the patients showing sustained virological response. Herein, the SAR leading to the discovery of 70 (SCH 503034), a novel, potent, selective, orally bioavailable NS3 protease inhibitor that has been advanced to clinical trials in human beings for the treatment of hepatitis C viral infections is described. X-ray structure of inhibitor 70 complexed with the NS3 protease and biological data are also discussed.

  6. An experimental investigation of multiple sulfur isotope fractionations during heterogenous reactions between SO2 and activated carbon

    NASA Astrophysics Data System (ADS)

    Hamasaki, H.; Watanabe, Y.; Ohmoto, H.

    2010-12-01

    . We have recognized that the δ34S of SO2 in the system continuously decreased during the experiments from -0.6 to -1.4‰ (relative to the initial value) at 200 °C, and from -1.0 to -1.2 ‰ at 250 °C. The Δ33S of SO2 continued to decrease from 0 to -0.18 ‰ at 200 °C and 0.03 to -0.05 ‰ at 250 °C. Mass balance calculations suggest that the bulk S in activated carbon increased its δ34S value from 1.4 to 12.1 ‰ at 200 °C and 3.2 to 16.7 ‰ at 250 °C; and increased the Δ33S value from 0 to 0.18 ‰ at 200 °C and from 0.07 to 0.32 ‰ at 250 °C. Results of the sequential S extraction from the solid run products (activated C) indicate the total S content of 0.9 wt%, mostly in the forms of Cr-reductive S compounds (e.g., sulfites and polysulfides) and non Cr-reductive S compounds (e.g., organic sulfur, elemental sulfur, and sulfates). Our experimental results indicate that the adsorption of SO2, the reduction of S4+ to S0 (and/or Sx2-), and the oxidation of C0 to C4+ continued to occur during the reaction between SO2 and activated carbon at 200 °C and 250 °C, and that the redox reactions produced larger sulfur isotope effects (both in δ34S and Δ33S) compared to a simple adsorption process under our experimental conditions.

  7. A high-resolution Sulphur Isotope Record of Neoarchean Atmospheric Chemistry: Deciphering the Driver of Atmospheric Bi-stability in the Prelude to the GOE.

    NASA Astrophysics Data System (ADS)

    Izon, G. J.; Zerkle, A.; Newton, R.; Poulton, S.; Eigenbrode, J.; Farquhar, J.; Claire, M.

    2014-12-01

    Quantitative estimates of the composition of the Late Archean atmosphere are integral to deciphering the drivers of planetary oxygenation in the early Paleoproterozoic. However, the majority of geochemical proxies from marine sediments only inform on planetary redox via inference, making direct constraints on the ancient atmosphere difficult to place. Fortunately, the quadruple S-isotope (QSI) record (δ34S, Δ33S, and Δ36S) is implicitly tied to the composition of the ancient atmosphere. We have generated coupled QSI and δ13COrg records from two cores through the Transvaal basin in South Africa (GKF01 and BH1-Sacha) and from three time-equivalent cores through the Hammersley basin in Western Australia. These records reveal similar, apparently synchronous, co-variation between deviations from "typical" Neoarchean Δ36S/Δ33S values and negative δ13COrg values (C-S anomalies). We have interpreted these trends to reflect increased incorporation of 13C-depleted substrates (methane) into sedimentary matter following apparently episodically enhanced methanogenesis in the prelude to the GOE. These records suggest the terminal Neoarchean atmosphere operated in a bi-stable fashion, oscillating between a clear skies and organic-rich hazy state (Zerkle et al., 2010; Izon et al., in review). We speculate that these C-S anomalies reflect enhanced nutrient availability, facilitating the proliferation of an oxygenic photosynthetic/methanogenic biosphere, concomitantly amplifying biogenic CH4 and O2 fluxes and altering atmospheric chemistry. Here we present a new S- and C-isotope data set, derived at unprecedented resolution, encompassing the youngest C-S anomaly identified in core GKF01. These analyses will be combined with Fe-speciation and trace-metal data to elucidate whether atmospheric methane levels were regulated by climatically driven changes in nutrient fluxes to the marine biosphere. Taken together, our research serves as an initial foray to determine how, and why

  8. Spatial distributions of sulphur species and sulphate-reducing bacteria provide insights into sulphur redox cycling and biodegradation hot-spots in a hydrocarbon-contaminated aquifer

    NASA Astrophysics Data System (ADS)

    Einsiedl, Florian; Pilloni, Giovanni; Ruth-Anneser, Bettina; Lueders, Tillman; Griebler, Christian

    2015-05-01

    Dissimilatory sulphate reduction (DSR) has been proven to be one of the most relevant redox reactions in the biodegradation of contaminants in groundwater. However, the possible role of sulphur species of intermediate oxidation state, as well as the role of potential re-oxidative sulphur cycling in biodegradation particularly at the groundwater table are still poorly understood. Here we used a combination of stable isotope measurements of SO42-, H2S, and S0 as well as geochemical profiling of sulphur intermediates with special emphasis on SO32-, S2O32-, and S0 to unravel possible sulphur cycling in the biodegradation of aromatics in a hydrocarbon-contaminated porous aquifer. By linking these results to the quantification of total bacterial rRNA genes and respiratory genes of sulphate reducers, as well as pyrotag sequencing of bacterial communities over depth, light is shed on possible key-organisms involved. Our results substantiate the role of DSR in biodegradation of hydrocarbons (mainly toluene) in the highly active plume fringes above and beneath the plume core. In both zones the concentration of sulphur intermediates (S0, SO32- and S2O32-) was almost twice that of other sampling-depths, indicating intense sulphur redox cycling. The dual isotopic fingerprint of oxygen and sulphur in dissolved sulphate suggested a re-oxidation of reduced sulphur compounds to sulphate especially at the upper fringe zone. An isotopic shift in δ34S of S0 of nearly +4‰ compared to the δ34S values of H2S from the same depth linked to a high abundance (∼10%) of sequence reads related to Sulphuricurvum spp. (Epsilonproteobacteria) in the same depth were indicative of intensive oxidation of S0 to sulphate in this zone. At the lower plume fringe S0 constituted the main inorganic sulphur species, possibly formed by abiotic re-oxidation of H2S with Fe(III)oxides subsequent to sulphate reduction. These results provide first insights into intense sulphur redox cycling in a hydrocarbon

  9. Assessment of paleo-oxygenation conditions on the Agua Nueva Formation (Cenomanian-Turonian), Central Mexico

    NASA Astrophysics Data System (ADS)

    Nuñez, F.; Canet, C.; Barragan-Manzo, R.; Alfonso, P.

    2013-05-01

    Organic-carbon-rich, laminated sediments are characteristic and widespread in the global stratigraphic record of the mid-Cretaceous, mainly during the Oceanic Anoxic Events (OAE's). In central-eastern Mexico, deposits of the Agua Nueva Formation are constituted by dark-gray, carbonaceous and laminated limestone with pyritic layers related to the Cenomanian-Turonian OAE 2. Herein, through different proxies, variations of paleo-redox conditions are studied in detail on a stratigraphic section of the Agua Nueva Formation. A first approach to redox conditions comes from the analysis of the stratigraphic record. Laminated fabrics and the paucity of bioturbation are typical features of a poorly oxygenated sedimentary environment. The presence of well-preserved fish remains and inoceramid bivalve shells is also consistent with those conditions. On the other hand, discrete light-colored and bioturbated thin levels indicate limited increases in the dissolved oxygen content. Geochemical proxies include δ13C in carbonates, δ34S in pyrite and the concentration of various redox-sensitive trace-elements. δ13C (VPDB) ranges from 0.39‰ to 1.30‰, whereas δ34Spy (VCDT) is between -41.23‰ and -11.27‰. The stratigraphic variation patterns of both isotopic values (δ13C and δ34S) are roughly opposite, reflecting changes in the burial of organic matter (OM) and, consequently, in the rate of bacterial sulphate reduction. Thus, positive 13C-rich carbonates represent lower free oxygen condition which enhanced burial flux of OM, tend to shift δ13C of carbonates toward positive values and triggered the incorporation of 32S into the sulfide by bacteria. This situation is also suggested by an enrichment of the sediments in V, Ni, Cr, Cu, Co, Zn, Mo and U. The abundance and size distribution of pyrite framboids proved to be in good agreement with the geochemical results. They also suggest dysoxic to anoxic conditions for the stratigraphic section studied. Both parameters have been

  10. Matrix and energy effects during in-situ determination of Cu isotope ratios by ultraviolet-femtosecond laser ablation multicollector inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Lazarov, Marina; Horn, Ingo

    2015-09-01

    Copper isotope compositions in Cu-bearing metals and minerals have been measured by deep (194 nm) ultraviolet femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (UV-fsLA-MC-ICP-MS). Pure Cu-metal, brass, and several Cu-rich minerals (chalcopyrite, enargite, covellite, malachite and cuprite) have been investigated. A long-term reproducibility of better than 0.08‰ at the 95% confidence limit on the NIST SRM 976 (National Institute of Standards and Technology) Cu-metal standard has been achieved with this technique. The δ65Cu values for all samples have been calculated by standard-sample-standard bracketing with NIST SRM 976. All analyses have been carried out using Ni as a mass discrimination monitor added by nebulization prior to entering the plasma torch. For further verification samples have been analysed by conventional solution nebulization MC-ICP-MS and the results obtained have been compared with those from UV-fsLA-MC-ICP-MS. Several potential matrix-induced molecular interferences on the mineral copper isotope ratio, such as (32S33S)+ and (32S-16O17O)+ do not affect the Cu isotope measurements on sulfides, while hydrides, such as Zn-H or doubly-charged Sn2 + that interfere Ni isotopes can be either neglected or stripped by calculation. Matrix independent Cu-isotope measurements are sensitive to the energy density (fluence) applied onto the sample and can produce artificial shifts in the obtained δ65Cu values which are on the order of 3‰ for Cu-metal, 0.5‰ for brass and 0.3‰ for malachite when using energy density of up to 2 J/cm2 for ablation. A positive correlation between applied energy density and the magnitude of the isotope ratio shift has been found in the energy density range from 0.2 to 1.3 J/cm2 which is below the ablation threshold for ns-laser ablation. The results demonstrate that by using appropriate low fluence it is possible to measure Cu isotopic ratios in native copper and Cu-bearing sulfides

  11. Linking the Fe-, Mo-, and Cr isotope records with the multiple S isotope record of Archean sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Ohmoto, H.; Watanabe, Y.

    2011-12-01

    Researchers have interpreted the isotopic data of redox sensitive elements (e.g., Fe, Mo and Cr) in Archean- and Proterozoic-aged sedimentary rocks within a framework of an atmospheric O2 evolution model that relied on an interpretation of the multiple sulfur isotopic record of sedimentary rocks. The current paradigm is that the anomalous isotopic fractionations of sulfur (AIF-S, or MIF-S) in sedimentary rocks were created by the UV photolysis of volcanic SO2 in an O2-poor (i.e., pO2 < 1 ppm) atmosphere, and that the rise of atmospheric pO2 to > 1 ppm occurred at ~2.45 Ga. However, this paradigm has recently encountered the following serious problems: (1) UV photolysis of SO2 by a broad-band UV lamp, which simulates the UV spectra of the sun light, produced the δ34S33S values for the S0 and SO4 that are significantly different from >90% of data on natural samples. (2) Many Archean-age sedimentary rocks do not exhibit AIF-S signatures. (3) Strong AIF-S signatures are typically found in organic C- and pyrite rich Archean-age black shales that were altered by submarine hydrothermal fluids during the early diagenetic stage of the rocks. (4) H2S, rather than SO2, was probably the dominant S-bearing volcanic gas on an anoxic Earth. Yet, UV photolysis of H2S does not generate AIF-S. (5) Some post-2.0 Ga natural samples were found to possess strong AIF-S signatures, such as sulfates in air pollutants that were produced by coal burning in an oxygen-rich atmosphere. Lasaga et al. (2008) demonstrated theoretically that chemisorption reactions between some solid surfaces and S-bearing aqueous (or gaseous) species, such as between organic matter and aqueous sulfate, may generate AIF-S. Watanabe et al. (2009; in prep.) demonstrated experimentally that reactions between simple amino acid crystals and sulfate under hydrothermal conditions produced AIF-S signatures that matched with more than 90% of data on natural samples. These studies, as well as the observed correlations

  12. A Rare Glimpse of Paleoarchean Life: Geobiology of an Exceptionally Preserved Microbial Mat Facies from the 3.4 Ga Strelley Pool Formation, Western Australia

    PubMed Central

    Duda, Jan-Peter; Van Kranendonk, Martin J.; Thiel, Volker; Ionescu, Danny; Strauss, Harald; Schäfer, Nadine; Reitner, Joachim

    2016-01-01

    Paleoarchean rocks from the Pilbara Craton of Western Australia provide a variety of clues to the existence of early life on Earth, such as stromatolites, putative microfossils and geochemical signatures of microbial activity. However, some of these features have also been explained by non-biological processes. Further lines of evidence are therefore required to convincingly argue for the presence of microbial life. Here we describe a new type of microbial mat facies from the 3.4 Ga Strelley Pool Formation, which directly overlies well known stromatolitic carbonates from the same formation. This microbial mat facies consists of laminated, very fine-grained black cherts with discontinuous white quartz layers and lenses, and contains small domical stromatolites and wind-blown crescentic ripples. Light- and cathodoluminescence microscopy, Raman spectroscopy, and time of flight—secondary ion mass spectrometry (ToF-SIMS) reveal a spatial association of carbonates, organic material, and highly abundant framboidal pyrite within the black cherts. Nano secondary ion mass spectrometry (NanoSIMS) confirmed the presence of distinct spheroidal carbonate bodies up to several tens of μm that are surrounded by organic material and pyrite. These aggregates are interpreted as biogenic. Comparison with Phanerozoic analogues indicates that the facies represents microbial mats formed in a shallow marine environment. Carbonate precipitation and silicification by hydrothermal fluids occurred during sedimentation and earliest diagenesis. The deciphered environment, as well as the δ13C signature of bulk organic matter (-35.3‰), are in accord with the presence of photoautotrophs. At the same time, highly abundant framboidal pyrite exhibits a sulfur isotopic signature (δ34S = +3.05‰; Δ33S = 0.268‰; and Δ36S = -0.282‰) that is consistent with microbial sulfate reduction. Taken together, our results strongly support a microbial mat origin of the black chert facies, thus

  13. A Rare Glimpse of Paleoarchean Life: Geobiology of an Exceptionally Preserved Microbial Mat Facies from the 3.4 Ga Strelley Pool Formation, Western Australia.

    PubMed

    Duda, Jan-Peter; Van Kranendonk, Martin J; Thiel, Volker; Ionescu, Danny; Strauss, Harald; Schäfer, Nadine; Reitner, Joachim

    2016-01-01

    Paleoarchean rocks from the Pilbara Craton of Western Australia provide a variety of clues to the existence of early life on Earth, such as stromatolites, putative microfossils and geochemical signatures of microbial activity. However, some of these features have also been explained by non-biological processes. Further lines of evidence are therefore required to convincingly argue for the presence of microbial life. Here we describe a new type of microbial mat facies from the 3.4 Ga Strelley Pool Formation, which directly overlies well known stromatolitic carbonates from the same formation. This microbial mat facies consists of laminated, very fine-grained black cherts with discontinuous white quartz layers and lenses, and contains small domical stromatolites and wind-blown crescentic ripples. Light- and cathodoluminescence microscopy, Raman spectroscopy, and time of flight-secondary ion mass spectrometry (ToF-SIMS) reveal a spatial association of carbonates, organic material, and highly abundant framboidal pyrite within the black cherts. Nano secondary ion mass spectrometry (NanoSIMS) confirmed the presence of distinct spheroidal carbonate bodies up to several tens of μm that are surrounded by organic material and pyrite. These aggregates are interpreted as biogenic. Comparison with Phanerozoic analogues indicates that the facies represents microbial mats formed in a shallow marine environment. Carbonate precipitation and silicification by hydrothermal fluids occurred during sedimentation and earliest diagenesis. The deciphered environment, as well as the δ13C signature of bulk organic matter (-35.3‰), are in accord with the presence of photoautotrophs. At the same time, highly abundant framboidal pyrite exhibits a sulfur isotopic signature (δ34S = +3.05‰; Δ33S = 0.268‰; and Δ36S = -0.282‰) that is consistent with microbial sulfate reduction. Taken together, our results strongly support a microbial mat origin of the black chert facies, thus providing

  14. A MOLECULAR LINE SURVEY OF THE EXTREME CARBON STAR CRL 3068 AT MILLIMETER WAVELENGTHS

    SciTech Connect

    Zhang Yong; Kwok, Sun; Nakashima, Jun-ichi E-mail: sunkwok@hku.hk

    2009-08-01

    We present the results of a molecular line survey of the extreme carbon star CRL 3068. The observations were carried out with the Arizona Radio Observatory (ARO) 12 m telescope and the Heinrich Hertz Submillimeter Telescope (SMT) at the {lambda} 2 mm and {lambda} 1.3 mm atmospheric windows. The observations cover the frequency bands from 130 to 162 GHz and 219.5 to 267.5 GHz. The typical sensitivities achieved are T{sub R} < 15 mK and T{sub R} < 7 mK for the ARO 12 m and SMT, respectively. Seventy-two individual emission features belonging to 23 molecular species and isotopologues were detected. Only three faint lines remain unidentified. The species c-C{sub 3}H, CH{sub 3}CN, SiC{sub 2}, and the isotopologues, C{sup 17}O, C{sup 18}O, HC{sup 15}N, HN{sup 13}C, C{sup 33}S, C{sup 34}S, {sup 13}CS, {sup 29}SiS, and {sup 30}SiS are detected in this object for the first time. Rotational-diagram analysis is carried out to determine the column densities and excitation temperatures. The isotopic ratios of the elements C, N, O, S, and Si have also been estimated. The results are consistent with stellar CNO processing and suggest that CRL 3068 is more carbon rich than IRC+10216 and CIT 6. It is also shown that the chemical composition in CRL 3068 is somewhat different from that in IRC+10216 with a more extensive synthesis of cyclic and long-chain molecules in CRL 3068. The results will provide valuable clues for better understanding circumstellar chemistry.

  15. The Fundamental Structure of UV-Irradiated Cloud Edges: Combined ALMA and IRAM-30m Observations of the Orion Bar

    NASA Astrophysics Data System (ADS)

    Goicoechea, J.; Cuadrado, S.; Pety, J.; Ag'undez, M.; Cernicharo, J.; Chapillon, E.; Dumas, G.; Fuente, A.; Gerin, M.; Joblin, C.; Marcelino, N.; Müller, H. S. P.; Pilleri, P.

    2015-12-01

    The Orion Bar is the prototypical photodissociation region (PDR) exposed to a far-UV radiation field (FUV) of a few 104 times the mean interstellar field. Because of its proximity and nearly edge-on orientation, it provides a unique laboratory to study the physical and chemical gradients of a strongly FUV-illuminated molecular cloud. Using ALMA at ˜350 GHz, we have observed a field-of-view of ˜40”×40” toward the Orion Bar PDR consisting of a mosaic of 27 Nyquist-sampled pointings. These observations provide an unprecedented high angular resolution view (˜1” or ˜414 AU at the distance to Orion) of the most exposed molecular cloud edge. In addition, ACA and IRAM-30m maps were used to produce the short-spacing visibilities filtered out by the ALMA array. These interferometric observations complement a complete line survey we have carried out using the IRAM-30m telescope between ˜80 GHz and ˜360 GHz. Despite being a harsh environment, over 60 species with up to 6 atoms have been identified, including main isotopologues (D, 13C, 18O, 17O, 34S, 33S, and 15N). The first molecular line images of the Orion Bar obtained with ALMA at ˜1” resolution reveal the fundamental structure in density and temperature of the molecular gas as well as its complex kinematics at an unprecedented spatial resolution. This early data set also allowed us to compute corrected line frequencies for SH+, an interesting hydride tracing reactions of S+ with vibrationally excited H2 in the PDR edge.

  16. Volcanic sulfate aerosol formation in the troposphere

    NASA Astrophysics Data System (ADS)

    Martin, Erwan; Bekki, Slimane; Ninin, Charlotte; Bindeman, Ilya

    2014-11-01

    The isotopic composition of volcanic sulfate provides insights into the atmospheric chemical processing of volcanic plumes. First, mass-independent isotopic anomalies quantified by Δ17O and to a lesser extent Δ33S and Δ36S in sulfate depend on the relative importance of different oxidation mechanisms that generate sulfate aerosols. Second, the isotopic composition of sulfate (δ34S and δ18O) could be an indicator of fractionation (distillation/condensation) processes occurring in volcanic plumes. Here we present analyses of O- and S isotopic compositions of volcanic sulfate absorbed on very fresh volcanic ash from nine moderate historical eruptions in the Northern Hemisphere. Most of our volcanic sulfate samples, which are thought to have been generated in the troposphere or in the tropopause region, do not exhibit any significant mass-independent fractionation (MIF) isotopic anomalies, apart from those from an eruption of a Mexican volcano. Coupled to simple chemistry model calculations representative of the background atmosphere, our data set suggests that although H2O2 (a MIF-carrying oxidant) is thought to be by far the most efficient sulfur oxidant in the background atmosphere, it is probably quickly consumed in large dense tropospheric volcanic plumes. We estimate that in the troposphere, at least, more than 90% of volcanic secondary sulfate is not generated by MIF processes. Volcanic S-bearing gases, mostly SO2, appear to be oxidized through channels that do not generate significant isotopically mass-independent sulfate, possibly via OH in the gas phase and/or transition metal ion catalysis in the aqueous phase. It is also likely that some of the sulfates sampled were not entirely produced by atmospheric oxidation processes but came out directly from volcanoes without any MIF anomalies.

  17. Coupled Fe and S isotope variations in pyrite nodules from Archean shale

    NASA Astrophysics Data System (ADS)

    Marin-Carbonne, Johanna; Rollion-Bard, Claire; Bekker, Andrey; Rouxel, Olivier; Agangi, Andrea; Cavalazzi, Barbara; Wohlgemuth-Ueberwasser, Cora C.; Hofmann, Axel; McKeegan, Kevin D.

    2014-04-01

    Iron and sulfur isotope compositions recorded in ancient rocks and minerals such as pyrite (FeS2) have been widely used as a proxy for early microbial metabolisms and redox evolution of the oceans. However, most previous studies focused on only one of these isotopic systems. Herein, we illustrate the importance of in-situ and coupled study of Fe and S isotopes on two pyrite nodules in a c. 2.7 Ga shale from the Bubi Greenstone Belt (Zimbabwe). Fe and S isotope compositions were measured both by bulk-sample mass spectrometry techniques and by ion microprobe in-situ methods (Secondary Ion Mass Spectrometry, SIMS). Spatially-resolved analysis across the nodules shows a large range of variations at micrometer-scale for both Fe and S isotope compositions, with δ56Fe and δ34S values from -2.1 to +0.7‰ and from -0.5 to +8.2‰, respectively, and Δ33S values from -1.6 to +2.9‰. The Fe and S isotope variations in these nodules cannot be explained by tandem operation of Dissimilatory Iron Reduction (DIR) and Bacterial Sulfate Reduction (BSR) as was previously proposed, but rather they reflect the contributions of different Fe and S sources during a complex diagenetic history. Pyrite formed from two different mineral precursors: (1) mackinawite precipitated in the water column, and (2) greigite formed in the sediment during early diagenesis. The in-situ analytical approach reveals a complex history of the pyrite nodule growth and allows us to better constrain environmental conditions during the Archean.

  18. A COMPLETE SPECTROSCOPIC CHARACTERIZATION OF SO AND ITS ISOTOPOLOGUES UP TO THE TERAHERTZ DOMAIN

    SciTech Connect

    Martin-Drumel, M. A.; Hindle, F.; Mouret, G.; Cuisset, A.; Cernicharo, J.

    2015-02-01

    In order to obtain accurate terahertz center frequencies for SO and its isotopologues, we have studied the absorption spectrum of SO, {sup 34}SO, and {sup 33}SO up to 2.5 THz using continuous-wave terahertz photomixing based on a frequency comb providing an accuracy down to 10 kHz. Sulfur monoxide was produced in a radio frequency discharge of air in a cell containing pure sulfur. Together with the strong absorption signal of the main isotopologue, transitions of {sup 34}SO ({sup 34}S: 4.21%) and {sup 33}SO ({sup 33}S: 0.75%) were observed in natural abundance. The newly observed transitions constitute an extension of the observed rotational quantum numbers of the molecule toward higher N values, allowing an improvement of the molecular parameters for the three species. An isotopically invariant fit has been performed based on pure rotational and ro-vibrational transitions of all SO isotopologues, enabling their accurate line position prediction at higher frequencies. Thanks to this new set of parameters, it is now possible to predict with very high accuracy the frequencies of the ro-vibrational lines. This should enable the research of SO in the mid-IR using ground-based IR telescopes, space-based telescope archives (Infrared Space Observatory, Spitzer), and future space missions such as the James Webb Space Telescope. This set of parameters is particularly well adapted for the detection of SO lines in O-rich evolved stars or in molecular clouds in absorption against bright IR sources.

  19. Dipole-dipole resonance line shapes in a cold Rydberg gas

    NASA Astrophysics Data System (ADS)

    Richards, B. G.; Jones, R. R.

    2016-04-01

    We have explored the dipole-dipole mediated, resonant energy transfer reaction, 32 p3 /2+32 p3 /2→32 s +33 s , in an ensemble of cold 85Rb Rydberg atoms. Stark tuning is employed to measure the population transfer probability as a function of the total electronic energy difference between the initial and final atom-pair states over a range of Rydberg densities, 2 ×108≤ρ ≤3 ×109 cm-3. The observed line shapes provide information on the role of beyond nearest-neighbor interactions, the range of Rydberg atom separations, and the electric field inhomogeneity in the sample. The widths of the resonance line shapes increase approximately linearly with the Rydberg density and are only a factor of 2 larger than expected for two-body, nearest-neighbor interactions alone. These results are in agreement with the prediction [B. Sun and F. Robicheaux, Phys. Rev. A 78, 040701(R) (2008), 10.1103/PhysRevA.78.040701] that beyond nearest-neighbor exchange interactions should not influence the population transfer process to the degree once thought. At low densities, Gaussian rather than Lorentzian line shapes are observed due to electric field inhomogeneities, allowing us to set an upper limit for the field variation across the Rydberg sample. At higher densities, non-Lorentzian, cusplike line shapes characterized by sharp central peaks and broad wings reflect the random distribution of interatomic distances within the magneto-optical trap (MOT). These line shapes are well reproduced by an analytic expression derived from a nearest-neighbor interaction model and may serve as a useful fingerprint for characterizing the position correlation function for atoms within the MOT.

  20. Atmospheric DMS and Biogenic Sulfur aerosol measurements in the Arctic

    NASA Astrophysics Data System (ADS)

    Ghahremaninezhadgharelar, R.; Norman, A. L.; Wentworth, G.; Burkart, J.; Leaitch, W. R.; Abbatt, J.; Sharma, S.; Desiree, T. S.

    2014-12-01

    Dimethyl Sulfide (DMS) and its oxidation products were measured on the board of the Canadian Coast Guard Ship (CCGS) Amundsen and above melt ponds in the Arctic during July 2014 in the context of the NETCARE study which seeks to understand the effect of DMS and its oxidation products with respect to aerosol nucleation, as well as its effect on cloud and precipitation properties. The objective of this study is to quantify the role of DMS in aerosol growth and activation in the Arctic atmosphere. Atmospheric DMS samples were collected from different altitudes, from 200 to 9500 feet, aboard the POLAR6 aircraft expedition to determine variations in the DMS concentration and a comparison was made to shipboard DMS measurements and its effects on aerosol size fractions. The chemical and isotopic composition of sulfate aerosol size fractions was studied. Sulfur isotope ratios (34S/32S) offer a way to determine the oceanic DMS contribution to aerosol growth. The results are expected to address the contribution of anthropogenic as well as biogenic sources of aerosols to the growth of the different aerosol size fractions. In addition, aerosol sulfate concentrations were measured at the same time within precipitation and fogs to compare with the characteristics of aerosols in each size fraction with the characteristics of the sulfate in each medium. This measurement is expected to explain the contribution of DMS oxidation in aerosol activation in the Arctic summer. Preliminary results from the measurement campaign for DMS and its oxidation products in air, fog and precipitation will be presented.

  1. EXPLORING IO'S ATMOSPHERIC COMPOSITION WITH APEX: FIRST MEASUREMENT OF {sup 34}SO{sub 2} AND TENTATIVE DETECTION OF KCl

    SciTech Connect

    Moullet, A.; Lellouch, E.; Moreno, R.; Gurwell, M.; Black, J. H; Butler, B.

    2013-10-10

    The composition of Io's tenuous atmosphere is poorly constrained. Only the major species SO{sub 2} and a handful of minor species have been positively identified, but a variety of other molecular species should be present, based on thermochemical equilibrium models of volcanic gas chemistry and the composition of Io's environment. This paper focuses on the spectral search for expected yet undetected molecular species (KCl, SiO, S{sub 2}O) and isotopes ({sup 34}SO{sub 2}). We analyze a disk-averaged spectrum of a potentially line-rich spectral window around 345 GHz, obtained in 2010 at the APEX 12 m antenna. Using different models assuming either extended atmospheric distributions or a purely volcanically sustained atmosphere, we tentatively measure the KCl relative abundance with respect to SO{sub 2} and derive a range of 4 × 10{sup –4}-8 × 10{sup –3}. We do not detect SiO or S{sub 2}O and present new upper limits on their abundances. We also present the first measurement of the {sup 34}S/{sup 32}S isotopic ratio in gas phase on Io, which appears to be twice as high as the Earth and interstellar medium reference values. Strong lines of SO{sub 2} and SO are also analyzed to check for longitudinal variations of column density and relative abundance. Our models show that, based on their predicted relative abundance with respect to SO{sub 2} in volcanic plumes, both the tentative KCl detection and SiO upper limit are compatible with a purely volcanic origin for these species.

  2. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    USGS Publications Warehouse

    Church, C.D.; Wilkin, R.T.; Alpers, C.N.; Rye, R.O.; Blaine, R.B.

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

  3. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    PubMed Central

    Church, Clinton D; Wilkin, Richard T; Alpers, Charles N; Rye, Robert O; McCleskey, R Blaine

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2–3 ‰ heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. PMID:17956615

  4. NEW MASER EMISSION FROM NONMETASTABLE AMMONIA IN NGC 7538. II. GREEN BANK TELESCOPE OBSERVATIONS INCLUDING WATER MASERS

    SciTech Connect

    Hoffman, Ian M.; Seojin Kim, Stella

    2011-12-15

    We present new maser emission from {sup 14}NH{sub 3} (9,6) in NGC 7538. Our observations include the known spectral features near v{sub LSR} = -60 km s{sup -1} and -57 km s{sup -1} and several more features extending to -46 km s{sup -1}. In three epochs of observation spanning two months we do not detect any variability in the ammonia masers, in contrast to the >10-fold variability observed in other {sup 14}NH{sub 3} (9,6) masers in the Galaxy over comparable timescales. We also present observations of water masers in all three epochs for which emission is observed over the velocity range -105 km s{sup -1} < v{sub LSR} < -4 km s{sup -1}, including the highest velocity water emission yet observed from NGC 7538. Of the remarkable number of maser species in IRS 1, H{sub 2}O and, now, {sup 14}NH{sub 3} are the only masers known to exhibit emission outside of the velocity range -62 km s{sup -1} < v{sub LSR} < -51 km s{sup -1}. However, we find no significant intensity or velocity correlations between the water emission and ammonia emission. We also present a non-detection in the most sensitive search to date toward any source for emission from the CC{sup 32}S and CC{sup 34}S molecules, indicating an age greater than Almost-Equal-To 10{sup 4} yr for IRS 1-3. We discuss these findings in the context of embedded stellar cores and recent models of the region.

  5. SIMS and NanoSIMS analyses of Mesoproterozoic individual microfossils indicating continuous oxygen-producing photosynthesis in Proterozoic Ocean

    NASA Astrophysics Data System (ADS)

    Peng, X.; Guo, Z.; House, C. H.; Chen, S.; Ta, K.

    2015-12-01

    Well-preserved microfossils in the stromatolites from the Gaoyuzhuang Formation (~1500Ma), which is younger than the Gunflint Formation (~1880Ma) and older than the Bitter Springs Formation (~850Ma), may play key roles in systematizing information about the evolution of early life and environmental changes in the Proterozoic Ocean. Here, a combination of light microscopy (LM), scanning electron microscopy (SEM), focused ion beam (FIB), nano-scale secondary ion mass spectrometry (NanoSIMS) and secondary ion mass spectrometry (SIMS) were employed to characterize the morphology, elemental distributions and carbon isotope values of individual microfossils in the stromatolites from the Gaoyuahzuang Formation. Light microscopy analyses show that abundant filamentous and coccoid microfossils are exceptionally well preserved in chert. NanoSIMS analyses show that metabolically important elements such as 12C-, 13C-, 12C14N-, 32S-, and 34S- are concentrated in these microfossils and that the variations in the concentrations of these elements are similar, establishing the elemental distributions in incontestably biogenic microstructures. Carbon isotope (δ13C) values of individual microfossils range from -32.2‰ ± 0.9‰ to -23.3‰ ± 1.0‰ (weighted mean= -28.9‰ ± 0.1‰), consistent with carbon fixation via the Calvin cycle. The elevated δ13C values of the microfossils from Early-, Meso- to Late Proterozoic Era, possibly indicate decreasing CO2 and increasing O2 concentrations in the Proterozoic atmosphere. Our results, for the first time, provided the element distributions and cell specific carbon isotope values on convincing Mesoproterozoic cyanobacterial fossils, supporting continuous oxygen-producing photosynthesis in the Proterozoic Ocean.

  6. Isotope geochemistry of the Amazon Basin: A reconnaissance

    NASA Astrophysics Data System (ADS)

    Longinelli, A.; Edmond, J. M.

    1983-04-01

    On the transects of the Amazon River made by the Alpha Helix in 1976 and 1977, an extensive suite of samples was collected for isotopic analyses. The water isotopes (18O/16O, D/H) were determined in atmospheric water vapour and in river, rain, and leaf waters. 13C/12C ratios were measured in the dissolved and atmospheric CO2. Determinations were made of 34S/32S and oxygen isotopes in dissolved sulphate. The effect of `continentality' on the water isotopes is minor reflecting the large scale recycling by evapotranspiration from the huge area of forest within the basin. Variations in the isotopic abundances between 1976 (June-July, dry season) and 1977 (May-June, end of wet season) are consistent with the changes in meteorological conditions. The isotopic composition of the CO2, both atmospheric and dissolved, is dominated by biological effects. In 1976 the dissolved CO2 showed downstream variations from -14‰ at Iquitos in Peru to -22‰ in the lower reaches. In 1977, no systematic trend was apparent, the data ranging around -19‰. The values for atmospheric CO2 decrease inland from marine values at the mouth to around -15‰ at Manaus. During the dry season (1976) the values in the interior, western basin were homogeneous at -20‰. In the wet season there were considerable variations reflecting atmospheric instabilities with the average value being about -13‰. The sulphur isotopic composition of the dissolved sulphate is remarkably uniform at around 7‰. In 1977 the 18O values in the sulphate decreased systematically downstream from 8‰ in Peru to 3‰ at the mouth, consistent with a progressive, redox-mediated exchange with water and dissolved oxygen. In 1977 the values increased to over 11‰, apparently indicating exchange with a highly fractionated reservoir of dissolved oxygen perhaps in the semireducing environment of the flood plain lakes.

  7. Stable isotope variation as a tool to trace the authenticity of beef.

    PubMed

    Boner, M; Förstel, H

    2004-01-01

    Organic beef coming principally from Germany was analysed for the hydrogen, carbon, oxygen, nitrogen and sulfur stable isotopic composition to test the possibility of tracing back the geographical origin. Since there is a well-known pattern of D/H and 18O/16O in meteoric water and in ground water, there is an existing link to tissue water in the beef. By including the stable isotope ratios of the other elements of life further information is available: soils show different isotope ratios of 15N/14N and 34S/32S depending on the geological composition, cultivation and atmospheric sulfur deposition. As organic farming is mainly obliged to use only their produced fodder, that ratio is reflected in the beef as well. Different organic beef samples from various German farms have been collected and analysed over nearly two years. To check the differentiation of foreign beef, samples from Argentina and Chile were also included in the study. The analyses of meat samples indicate that it is possible to trace back the region (e.g. Argentina and Germany) by using isotopes of oxygen and hydrogen. A local geographical differentiation can be done by using the stable isotopes of nitrogen and sulfur, as was demonstrated for three farms in Colonia Bay. An optimal differentiation also depends on the quality of further information (e.g. the season, kind of cattle breeding or the declaration of the local geographical origin). Certainly authenticity of beef is not only linked with the geographical origin but can also reflect the differentiation of organic and conventional farming. The fodder of organic cattle farming consists mainly of C3 plants and the use of C4 plants is more usual in conventional cattle farming. A 13C/12C ratio above -20 per thousand appears as a limit for organic farming. Increased values have to be controlled based on their authenticity. PMID:14634708

  8. Geochemical constraints on chemolithoautotrophic metabolism by microorganisms in seafloor hydrothermal systems.

    PubMed

    McCollom, T M; Shock, E L

    1997-10-01

    Mixing of hydrothermal fluids and seawater at the ocean floor, combined with slow reaction kinetics for oxidation/reduction reactions, provides a source of metabolic energy for chemolithotrophic microorganisms which are the primary biomass producers for an extensive submarine ecosystem that is essentially independent of photosynthesis. Thermodynamic models are used to explore geochemical constraints on the amount of metabolic energy potentially available from chemosynthetic reactions involving S, C, Fe, and Mn compounds during mixing of hydrothermal fluids with seawater. For the vent fluid used in the calculations (EPR 21 degrees N OBS), the model indicates that mixing environments are favorable for oxidation of H2S, CH4, Fe2+ and Mn2+ only below approximately 38 degrees C, with methanogenesis and reduction of sulfate or S degrees favored at higher temperatures, suggesting that environments dominated by mixing provide habitats for mesophilic (but not thermophilic) aerobes and thermophilic (but not mesophilic) anaerobes. A maximum of approximately 760 cal per kilogram vent fluid is available from sulfide oxidation while between 8 and 35 cal/kg vent fluid is available from methanotrophy, methanogenesis, oxidation of Fe or Mn, or sulfate reduction. The total potential for chemosynthetic primary production at deep-sea hydrothermal vents globally is estimated to be about 10(13) g biomass per year, which represents approximately 0.02% of the global primary production by photosynthesis in the oceans. Thermophilic methanogens and sulfate- and S degree-reducers are likely to be the predominant organisms in the walls of vent chimneys and in the diffuse mixing zones beneath warm vents, where biological processes may contribute to the high methane concentrations of vent fluids and heavy 34S/32S ratios of vent sulfide minerals. The metabolic processes taking place in these systems may be analogs of the first living systems to evolve on the Earth. PMID:11541662

  9. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water.

    PubMed

    Church, Clinton D; Wilkin, Richard T; Alpers, Charles N; Rye, Robert O; McCleskey, R Blaine

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 per thousand heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. PMID:17956615

  10. Isotopic mapping of transition-state structural features associated with enzymic catalysis of methyl transfer

    SciTech Connect

    Rodgers, J.; Femec, D.A.; Schowen, R.L.

    1982-06-16

    For comparison of the molecular structures of nonenzymic and enzymic sulfur-to-oxygen transmethylation transition states by the use of kinetic isotope effects, a series of isotopic maps is produced. In these, contours of constant isotope effect are displayed vs. the Pauling bond orders B/sub CS/ and B/sub CO/, for the carbon-sulfur and carbon-oxygen bonds, respectively, taken as independent variables to describe the transition states. Maps are calculated by the BEBOVIB approach for k(CH/sub 3/)/k(CD/sub 3/), k(/sup 12/CH/sub 3/)/k(/sup 13/CH/sub 3/), k(/sup 16/O)/k(/sup 18/O), and k(/sup 32/S)/k(/sup 34/S), with two models for the reaction coordinate, two force-field assumptions, and four temperatures. Nonenzymic isotope effects and isotope effects for catechol-O-methyltransferase action are then used to construct figures on the CH/sub 3//CD/sub 3/ and /sup 12/CH/sub 3///sup 13/CH/sub 3/ maps which correspond to allowed spaces of transition-states structures. Superposition of the figures yields the spaces of transition-state structures simultaneously consistent with both hydrogen and carbon isotope effects. It is concluded that the enzyme compresses the S/sub N/2 transition state and that the compression of the C-O and C-S bonds may well be of the order of 0.15 A per bond and could conceivably be more than twice as large.

  11. Stellar Origins of Extremely 13C- and 15N-enriched Presolar SiC Grains: Novae or Supernovae?

    NASA Astrophysics Data System (ADS)

    Liu, Nan; Nittler, Larry R.; O'D. Alexander, Conel M.; Wang, Jianhua; Pignatari, Marco; José, Jordi; Nguyen, Ann

    2016-04-01

    Extreme excesses of 13C (12C/13C < 10) and 15N (14N/15N < 20) in rare presolar SiC grains have been considered diagnostic of an origin in classical novae, though an origin in core collapse supernovae (CCSNe) has also been proposed. We report C, N, and Si isotope data for 14 submicron- to micron-sized 13C- and 15N-enriched presolar SiC grains (12C/13C < 16 and 14N/15N < ˜100) from Murchison, and their correlated Mg-Al, S, and Ca-Ti isotope data when available. These grains are enriched in 13C and 15N, but with quite diverse Si isotopic signatures. Four grains with 29,30Si excesses similar to those of type C SiC grains likely came from CCSNe, which experienced explosive H burning occurred during explosions. The independent coexistence of proton- and neutron-capture isotopic signatures in these grains strongly supports heterogeneous H ingestion into the He shell in pre-supernovae. Two of the seven putative nova grains with 30Si excesses and 29Si depletions show lower-than-solar 34S/32S ratios that cannot be explained by classical nova nucleosynthetic models. We discuss these signatures within the CCSN scenario. For the remaining five putative nova grains, both nova and supernova origins are viable because explosive H burning in the two stellar sites could result in quite similar proton-capture isotopic signatures. Three of the grains are sub-type AB grains that are also 13C enriched, but have a range of higher 14N/15N. We found that 15N-enriched AB grains (˜50 < 14N/15N < ˜100) have distinctive isotopic signatures compared to putative nova grains, such as higher 14N/15N, lower 26Al/27Al, and lack of 30Si excess, indicating weaker proton-capture nucleosynthetic environments.

  12. Is white clover able to switch to atmospheric sulphur sources when sulphate availability decreases?

    PubMed

    Varin, Sébastien; Lemauviel-Lavenant, Servane; Cliquet, Jean-Bernard

    2013-05-01

    Sulphur (S) is one of the very few nutrients that plants can absorb either through roots as sulphate or via leaves in a gas form such as SO2 or H2S. This study was realized in a non-S-enriched atmosphere and its purpose was to test whether clover plants can increase their ability to use atmospheric S when sulphate availability decreases. A novel methodology measuring the dilution of (34)S provided from a nutrient solution by atmospheric (32)S was developed to measure S acquisition by Trifolium repens L. Clones of white clover were grown for 140 d in a hydroponic system with three levels of sulphate concentrations. S concentration in plants decreased with S deficiency and plant age. In the experimental conditions used here, S derived from atmospheric deposition (Sdad) constituted from 36% to 100% of the total S. The allocation of S coming from atmospheric and pedospheric sources depends on organs and compounds. Nodules appeared as major sinks for sulphate. A greater proportion of atmospheric S was observed in buffer-soluble proteins than in the insoluble S fraction. Decreasing the S concentration in the nutrient solution resulted in an increase in the Sdad:leaf area ratio and in an increase in the leaf:stolon and root:shoot mass ratios, suggesting that a plasticity in the partitioning of resources to organs may allow a higher gain of S by both roots and leaves. This study shows that clover can increase its ability to use atmospheric S even at low concentration when pedospheric S availability decreases. PMID:23645868

  13. Photochemical self-shielding as a source of non-mass-dependent isotope fractionation

    NASA Astrophysics Data System (ADS)

    Lyons, James; Stark, Glenn; Blackie, Doug; Pickering, Juliet; Heays, Alan

    2010-05-01

    Very large isotopic enrichments occur in the photolysis products of molecules that have line-type absorption spectra. Abundance-dependent line saturation, a process termed photochemical self-shielding, yields large non-mass-dependent (NMD) isotope effects, and has been proposed to have occurred in CO in the solar nebula (Clayton 2002) and SO2 in the early Earth atmosphere (Lyons 2007). The NMD signatures derived from photolysis of CO and SO2 are believed to be recorded in primitive meteorites inclusions (CAIs) and in Archean/Paleoproterozoic sulfur sediments, respectively. Comparison of theory and experiment can be used to distinguish self-shielding from other NMD processes. Recent low-resolution (~10 cm^-1) measurements of isotopic SO2 cross sections (Danielache et al. 2008) exhibit NMD effects when included in photoechemical models (Ueno et al. 2009), but not as a result of self-shielding. Higher resolution measurements (1-0.2 cm^-1) of isotopic cross sections are in progress at Imperial College. Inclusion of preliminary 1 cm^-1 resolution cross sections in a photochemical model for Earth's early atmosphere clearly demonstrates that isotopic self-shielding is present, yielding d33S>0 and d34S>0 in photoproduct SO. However, uncertainties in the measured cross sections also introduce NMD signatures. We are presently working to remove these uncertainties. Recent experiments on CO photodissociation at wavelengths ~91-108 nm show very large NMD effects in oxygen (Chakraborty et al. 2008). Because the measured NMD signatures are wavelength dependent, and differ in delta-values (i.e., d17O/d18O not equal unity), Chakraborty et al. claim that their experiments rule out CO self-shielding as the mechanism for the meteorite CAI slope-1 line. Here we show via model simulation of the experiments that the non-unity d17O/d18O values result primarily from self-shielding effects in both C16O and C18O. Also, model results indicate that the non-unity d17O/d18O values only arise for

  14. Fe Isotope Composition of Neoproterozoic Post-Glacial "Cap Dolostones"

    NASA Astrophysics Data System (ADS)

    Halverson, G. P.

    2005-12-01

    The largest variations in the Fe isotope composition in the geological record are found in sedimentary rocks, presumably as the result of redox transformations of iron during mineral precipitation, microbial processing, and diagenesis (Johnson et al., Cont. Min. Petrol., 2003). Systematic trends in the variability of the Fe isotope composition of sulfide minerals formed in ancient marine black shales broadly mirror patterns in sulfur isotope data (Δ33S, Δ34S), which are consistent with geological and other geochemical evidence for the progressive oxidation of the earth's surface during the Precambrian (Rouxel et al., Science, 2005). Therefore, the record of the Fe isotope composition of minerals formed in the marine environment appears to be a promising proxy for the redox evolution of the ocean. We have developed a method to extract the marine Fe isotope composition from carbonates in an attempt to establish higher resolution records of changes in marine redox changes than permitted by black shale geochemistry. We have applied this method to the study of ca. 635 Ma iron-rich dolostones, which are found in Neoproterozoic successions worldwide and immediately post-date a purported snowball (Marinoan) glaciation during which time the deep ocean is thought to have become anoxic (Hoffman et al., Science, 1998), allowing its Fe isotopic composition to evolve towards the composition of relatively light (δ57Fe vs. IRMM-14 ~ -0.6‰) hydrothermal iron (Beard et al., Geology, 2003). Fe isotope compositions were measured relative to IRMM-14 in medium-resolution mode on a Neptune MC-ICP-MS with a long-term external (2σ) reproducibility of < 0.04‰/amu. Preliminary data on dolomite samples from Svalbard, northern Namibia and northwest Canada show a range in δ57Fe values from -0.65 to 0.04‰, similar to the range found in siderite and Fe-rich dolomite in ancient BIFs (Johsnon et al., 2003) and to values for the Namibian cap dolostone reported by Leighton et al

  15. Isotopic mass independent signature of black crusts: a proxy for atmospheric aerosols formation in the Paris area (France).

    NASA Astrophysics Data System (ADS)

    Genot, Isabelle; Martin, Erwan; Yang, David Au; De Rafelis, Marc; Cartigny, Pierre; Wing, Boswell; Le Gendre, Erwann; Bekki, Slimane

    2016-04-01

    In view of the negative forcing of the sulfate aerosols on climate, a more accurate understanding of the formation of these particles is crucial. Indeed, despite the knowledge of their effects, uncertainties remain regarding the formation of sulfate aerosols, particularly the oxidation processes of S-bearing gases. Since the discovery of oxygen and sulfur mass independent fractionation (O- and S-MIF) processes on Earth, the sulfate isotopic composition became essential to investigate the atmospheric composition evolution and its consequences on the climate and the biosphere. Large amount of S-bearing compounds (SO2 mainly) is released into the atmosphere by anthropogenic and natural sources. Their oxidation in the atmosphere generates sulfate aerosols, H2SO4, which precipitate on the earth surface mainly as acid rain. One consequence of this precipitation is the formation of black crust on buildings made of carbonate stones. Indeed the chemical alteration of CaCO3 by H2SO4 leads to gypsum (CaSO4·2H2O) concretions on building walls. Associated to other particles, gypsum forms black-crusts. Therefore, black crusts acts as 'sulfate aerosol traps', meaning that their isotopic composition reveals the composition and thus the source and formation processes of sulfate aerosols in the atmosphere in a specific region. In this study we collected 37 black crusts on a 300km NW-SE profile centered on Paris (France). In our samples, sulfate represent 40wt.% and other particles 60wt.% of the black crusts. After sulfate extraction from each samples we measured their O- and S-isotopes composition. Variations of about 10‰ in δ18O and δ34S are observed and both O-MIF (Δ17O from 0 to 1.4‰) and S-MIF (Δ33S from 0 to -0.3‰) compositions have been measured. In regards to these compositions we can discuss the source and formation (oxidation pathways) of the sulfate aerosols in troposphere above the Paris region that covers urban, rural and coastal environments. Furthermore

  16. Tracing sources of crustal contamination using multiple S and Fe isotopes in the Hart komatiite-associated Ni-Cu-PGE sulfide deposit, Abitibi greenstone belt, Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Hiebert, R. S.; Bekker, A.; Houlé, M. G.; Wing, B. A.; Rouxel, O. J.

    2016-03-01

    Assimilation by mafic to ultramafic magmas of sulfur-bearing country rocks is considered an important contributing factor to reach sulfide saturation and form magmatic Ni-Cu-platinum group element (PGE) sulfide deposits. Sulfur-bearing sedimentary rocks in the Archean are generally characterized by mass-independent fractionation of sulfur isotopes that is a result of atmospheric photochemical reactions, which produces isotopically distinct pools of sulfur. Likewise, low-temperature processing of iron, through biological and abiotic redox cycling, produces a range of Fe isotope values in Archean sedimentary rocks that is distinct from the range of the mantle and magmatic Fe isotope values. Both of these signals can be used to identify potential country rock assimilants and their contribution to magmatic sulfide deposits. We use multiple S and Fe isotopes to characterize the composition of the potential iron and sulfur sources for the sulfide liquids that formed the Hart deposit in the Shaw Dome area within the Abitibi greenstone belt in Ontario (Canada). The Hart deposit is composed of two zones with komatiite-associated Ni-Cu-PGE mineralization; the main zone consists of a massive sulfide deposit at the base of the basal flow in the komatiite sequence, whereas the eastern extension consists of a semi-massive sulfide zone located 12 to 25 m above the base of the second flow in the komatiite sequence. Low δ56Fe values and non-zero δ34S and Δ33S values of the komatiitic rocks and associated mineralization at the Hart deposit is best explained by mixing and isotope exchange with crustal materials, such as exhalite and graphitic argillite, rather than intrinsic fractionation within the komatiite. This approach allows tracing the extent of crustal contamination away from the deposit and the degree of mixing between the sulfide and komatiite melts. The exhalite and graphitic argillite were the dominant contaminants for the main zone of mineralization and the eastern

  17. Triple oxygen and sulfur isotope analyses of sulfate extracted from voluminous volcanic ashes in the Oligocene John Day Formation: insight into dry climate conditions and ozone contribution to supereruptions

    NASA Astrophysics Data System (ADS)

    Workman, J.; Bindeman, I. N.; Martin, E.; Retallack, G.; Palandri, J. L.; Weldon, N.

    2014-12-01

    Large volume pyroclastic silicic eruptions emit hundreds of megatons of SO2 into the troposphere and stratosphere that is oxidized into sulfuric acid (H2SO4) by a variety of reactions with mass independent oxygen signatures (MIF), Δ17O>0. Sulfuric acid is then preserved as gypsum in parental volcanic deposits. Diagenic effects are mass dependent and can dilute, but otherwise do not affect MIF ratios. Pleistocene Yellowstone and Bishop tuffs and modern volcanic eruptions preserved under arid climate conditions in North American playa lakes, preserve small amounts of volcanic sulfate as gypsum. This gypsum's Δ17O>0, in combination with isotopic variations of δ18O, δ33S and δ34S is distinct from sedimentary sulfate and reveals its original MIF sulfate isotopic signal and the effect of super eruptions on the atmosphere, and ozone consumption in particular. We use linear algebraic equations to resolve volcanic versus sedimentary (MIF=0) sources. We have found that many large volume ignimbrites have very high initial Δ17O in volcanic sulfate that can only be acquired from reaction with stratospheric ozone. We here investigate nine thick (>2 m) ash beds ranging in age from ~33-23 Ma in the John Day Formation of central Oregon, including massive 28.6 Ma Picture Gorge tuff of newly identified Crooked River supercaldera. The 28.6 Ma Picture Gorge tuff (PGT) has the highest measured Δ17O of 3.5‰, and other tuffs (Tin Roof, Biotite, Deep Creek) have +1.3 to 3.4‰ Δ17O excesses. Sulfate from modern smaller tropospheric eruptions studied for comparison have a resolvable 0.4‰ range consistent with liquid-phase based H2O2 oxidation. The PGT is coeval with the ignimbrite flare-up in western N. America, the 28-29 Ma eruption of the 5000 km3 Fish Canyon tuff and the 28 Ma Never Summer Field eruption in Nebraska-Colorado that have the highest measured Δ17O of 6‰ (Bao et al. 2003). We speculate on the climatic/atmospheric effects of these multiple ~28 Ma supereruptions

  18. Barite in hydrothermal environments as a recorder of subseafloor processes: a multiple-isotope study from the Loki's Castle vent field.

    PubMed

    Eickmann, B; Thorseth, I H; Peters, M; Strauss, H; Bröcker, M; Pedersen, R B

    2014-07-01

    Barite chimneys are known to form in hydrothermal systems where barium-enriched fluids generated by leaching of the oceanic basement are discharged and react with seawater sulfate. They also form at cold seeps along continental margins, where marine (or pelagic) barite in the sediments is remobilized because of subseafloor microbial sulfate reduction. We test the possibility of using multiple sulfur isotopes (δ34S, Δ33S, ∆36S) of barite to identify microbial sulfate reduction in a hydrothermal system. In addition to multiple sulfur isotopes, we present oxygen (δ18O) and strontium (87Sr/86Sr) isotopes for one of numerous barite chimneys in a low-temperature (~20 °C) venting area of the Loki's Castle black smoker field at the ultraslow-spreading Arctic Mid-Ocean Ridge (AMOR). The chemistry of the venting fluids in the barite field identifies a contribution of at least 10% of high-temperature black smoker fluid, which is corroborated by 87Sr/86 Sr ratios in the barite chimney that are less radiogenic than in seawater. In contrast, oxygen and multiple sulfur isotopes indicate that the fluid from which the barite precipitated contained residual sulfate that was affected by microbial sulfate reduction. A sulfate reduction zone at this site is further supported by the multiple sulfur isotopic composition of framboidal pyrite in the flow channel of the barite chimney and in the hydrothermal sediments in the barite field, as well as by low SO4 and elevated H2S concentrations in the venting fluids compared with conservative mixing values. We suggest that the mixing of ascending H2- and CH4-rich high-temperature fluids with percolating seawater fuels microbial sulfate reduction, which is subsequently recorded by barite formed at the seafloor in areas where the flow rate is sufficient. Thus, low-temperature precipitates in hydrothermal systems are promising sites to explore the interactions between the geosphere and biosphere in order to evaluate the microbial impact on

  19. Multiple S isotopes, zircon Hf isotopes, whole-rock Sr-Nd isotopes, and spatial variations of PGE tenors in the Jinchuan Ni-Cu-PGE deposit, NW China

    NASA Astrophysics Data System (ADS)

    Duan, Jun; Li, Chusi; Qian, Zhuangzhi; Jiao, Jiangang; Ripley, Edward M.; Feng, Yanqing

    2016-04-01

    Previous geochemical data for the Jinchuan Ni-Cu-(platinum-group elements, PGE) deposit, the single largest magmatic sulfide deposit in the world, are derived primarily from the upper parts of the deposit. This paper reports new PGE and S-Hf-Sr-Nd isotope data for the lower parts of the deposit that have become accessible for sampling by ongoing underground mining activity. New PGE data from this study, together with previous results, indicate that PGE tenors in the bulk sulfide ores of the deposit increase eastward, except for two fault-offset ore zones which occur together within the western part of the deposit. Generally, these two ore zones show depletions in IPGE (Ir, Ru, Rh) but not in PPGE (Pt, Pd) and Cu, and more fractionated olivine and Cr-spinel compositions than the rest of the deposit. These differences can be explained by a more evolved parental magma for the IPGE-depleted ore zones. The eastward increase of PGE tenors in the rest of the deposit can be explained by upgrading of preexisting sulfide liquid in a subhorizontal conduit by a new surge of magma moving through the conduit from west to east, which took place before the formation of the IPGE-depleted ore zones. The Jinchuan ultramafic rocks are characterized by elevated initial 87Sr/86Sr ratios from 0.7077 to 0.7093, negative ɛ Nd values from -9.2 to -10.5, and zircon ɛ Hf values from -4 to -7. These data indicate up to 20 % of crustal contamination in the Jinchuan magma. Four of nine multiple sulfur isotope analyses for the Jinchuan deposit show anomalous ∆33S values varying from 0.12 to 2.67 ‰. These results, together with elevated δ34S values (>2 ‰) for some of the samples analyzed previously by other researchers, indicate the involvement of external sulfur from Archean and Proterozoic sedimentary rocks. Modeling results based on our olivine data and magma compositions estimated previously by other researchers indicate that fractional crystallization did not play a major role in

  20. Measurements of radioactive and stable sulfur isotopes at Mt. Everest and its geochemical implications

    NASA Astrophysics Data System (ADS)

    Lin, M.; Thiemens, M. H.; Zhang, Q.; Li, C.; Kang, S.; Hsu, S. C.; Zhang, Z.; Su, L.

    2015-12-01

    The Himalayas were recently identified as a global hotspot for deep stratosphere-to-troposphere transport (STT) during spring [1]. Although STT transport in this region may play a vital role in tropospheric chemistry, the hydrological cycle and aquatic ecosystems in Asia, there is no direct measurement of a specific chemical stratospheric tracer to verify and evaluate its possible impact. Here, cosmogenic 35S tracer (half-life: ~87 days) produced in the stratosphere was measured for the first time in surface snow and river runoff samples collected at Mt. Everest in April 2013 using a low-noise liquid scintillation spectroscopy [2]. Strikingly, we find extraordinarily high concentrations of 35S in these samples (>10 times higher than the southern Tibetan Plateau), verifying the Himalayas as a gateway of springtime STT. In light of this, two studies were conducted: a) Measurements of 35SO2 and 35SO42- at the southern Tibetan Plateau reveals that the oxidative life time of SO2 is reduced to 2.1 days under the influence of aged stratospheric air masses from the Himalayas. A concept box model for estimating the influence of STT on surface O3 using 35S tracer is proposed. b) Quadruple stable sulfur isotopes in a sediment core (~250 years) from the Gokyo Lake (the world's highest freshwater lake) [3] near Mt. Everest are being measured to investigate the possible impact of STT on sulfur budget at the Himalayas. The absence of sulfide suggests that bacterial sulfate reduction may be negligible in this lake. Enrichment of uranium (EF ≈ 10) in 20th century samples highlights the impact of atmospheric deposition. S-isotope sulfate anomalies are not found (∆33S and ∆36S ≈ 0‰), implying that sulfate in this lake may be mainly contributed by eolian dust or derived from rock. This is also supported by the low enrichments of most trace elements (EF ≈ 1). Rare earth elements will be used to assist in identifying the potential sources and interpreting the variation of

  1. A Precambrian-Cambrian oil play in southern Utah

    SciTech Connect

    Lillis, P.G.; Palacas, J.G.; Warden, A.

    1995-06-01

    The potential of the Precambrian Chuar Group as a petroleum source rock in southern Utah and northern Arizona resulted in the drilling of two wildcat wells in 1994. Both wells penetrated the Cambrian Tapeats Sandstone (the target reservoir rock) and presumably Precambrian rocks. The first well, Burnett Federal 36-1, was drilled east of Kanab, Utah (sec.36, T.34S., R.3W.) to a total depth of 5,365 ft and encountered Precambrian (?) reddish-brown sedimentary rocks at 4,790 ft. The Tapeats Sandstone had live oil shows and minor CO{sub 2} (?) gas shows. The second well, BHP Federal 28-1, was drilled near Capitol Reef (sec.28, T.33S., R.7E.) to a total depth of 6,185 ft and encountered the Tapeats Sandstone at 5,922 ft and Precambrian (?) phyllite at 6,125 ft. The upper Paleozoic rocks had abundant live oil/tar shows, and the Cambrian Bright Angel Shale and Tapeats Sandstone had numerous oil shows. There were no gas shows in the well except for a large CO{sub 2} gas kick in the Tapeats Sandstone. A drill-stem test from 5,950 to 6,185 ft yielded mostly CO{sub 2} (92%) and nitrogen gas (6%) and minor amounts of helium, argon, hydrogen, and methane. The {delta}{sup 13}C of the CO{sub 2} is -3.9 per mil PDB. The chemical composition of the extracted oil in the Cambrian sandstones is significantly different than oils produced from the Upper Valley field (upper Paleozoic reservoirs) and the tar sands that are widespread throughout southern and central Utah. However, the oil composition is similar in several aspects to the composition of some of the Precambrian Chuar Group bitumen extracts from the Grand Canyon area in Arizona. The encouraging features of both wells are the good reservoir characteristics and oil shows in the Tapeats Sandstone. In the BHP well the oil appears to be a new oil type, possibly derived from Precambrian or Cambrian source rocks.

  2. Endothelial dysfunction following prolonged sitting is mediated by a reduction in shear stress.

    PubMed

    Restaino, Robert M; Walsh, Lauren K; Morishima, Takuma; Vranish, Jennifer R; Martinez-Lemus, Luis A; Fadel, Paul J; Padilla, Jaume

    2016-03-01

    We and others have recently reported that prolonged sitting impairs endothelial function in the leg vasculature; however, the mechanism(s) remain unknown. Herein, we tested the hypothesis that a sustained reduction in flow-induced shear stress is the underlying mechanism by which sitting induces leg endothelial dysfunction. Specifically, we examined whether preventing the reduction in shear stress during sitting would abolish the detrimental effects of sitting on popliteal artery endothelial function. In 10 young healthy men, bilateral measurements of popliteal artery flow-mediated dilation were performed before and after a 3-h sitting period during which one foot was submerged in 42°C water (i.e., heated) to increase blood flow and thus shear stress, whereas the contralateral leg remained dry and served as internal control (i.e., nonheated). During sitting, popliteal artery mean shear rate was reduced in the nonheated leg (pre-sit, 42.9 ± 4.5 s(-1); and 3-h sit, 23.6 ± 3.3 s(-1); P < 0.05) but not in the heated leg (pre-sit, 38.9 ± 3.4 s(-1); and 3-h sit, 63.9 ± 16.9 s(-1); P > 0.05). Popliteal artery flow-mediated dilation was impaired after 3 h of sitting in the nonheated leg (pre-sit, 7.1 ± 1.4% vs. post-sit, 2.8 ± 0.9%; P < 0.05) but not in the heated leg (pre-sit: 7.3 ± 1.5% vs. post-sit, 10.9 ± 1.8%; P > 0.05). Collectively, these data suggest that preventing the reduction of flow-induced shear stress during prolonged sitting with local heating abolishes the impairment in popliteal artery endothelial function. Thus these findings are consistent with the hypothesis that sitting-induced leg endothelial dysfunction is mediated by a reduction in shear stress. PMID:26747508

  3. Submillimetric study of nearby galaxies: A tool for new extragalactic molecules

    NASA Astrophysics Data System (ADS)

    Villicana Pedraza, Ilhuiyolitzin; Guesten, Rolf; Armijos Abendaño, Jairo; Carreto, Francisco; Martin, Sergio; Martin-Pintado, Jesus; Requena-Torres, Miguel; Perez-Beaupuits, Juan Pablo

    2016-07-01

    We present the first submillimetre line survey of extragalactic sources carried out by APEX, the results were presented inside of Villicana-Pedraza phd thesis in 2015. The surveys cover the 0.8 mm atmospheric window toward NGC253, NGC4945 and Arp220. We found HCN, C2H, CN, CS, C34S, HCO+, HNC, CO, N2H+, CH3OH are presents in all the sources, while 13CO,C18O and C17O, HNCO, H2CO, H2CS, SO, NO, SO2 were detected toward NGC253 and NGC4945, 13CN, *CO+, OCS, H2S in Arp220, 13CS, NH2CN, SiO in NGC253, and c-C3H2 in NGC4945 were detected. Column densities and rotation temperatures have been determinate using the Local Thermodinamical Equilibrium(LTE) line profile simulation and fitting in the MADCUBA IJ software. The differences found in the 32S/34S and 18O/17O ratios between the GC and the starburst galaxies NGC 4945 and NGC 253 suggest that the gas is less processed in the latter than in the GC. The high 18O/17O ratios in the galaxies NGC 4945 and NGC 253 suggest also material less processed in the nuclei of these galaxies than in the GC. This is consistent with the claim that 17O is a more representative primary product than 18O in stellar nucleosynthesis (Wilson and Rood 1994); Also, we did a Multitransitions study of H3O+ at 307GHz, 364GHz, 388GHz and 396GHz. From our non-LTE analysis of H3O+ in NGC253 with RADEX we found that the collisional excitation cannot explain the observed intensity of the ortho 396 GHz line. Excitation by radiation from the dust in the Far-IR can roughly explain the observations if the H2 densities are relatively low. From the derived H3O+ column densities we conclude that the chemistry of this molecule is dominated by ionization produce by the starburst in NGC253 (UV radiation from the O stars) and Arp 220 (cosmic rays from the supernovae) and likely from the AGN in NGC4549 (X-rays ); We report, for the first time, the tentative detection of the molecular ion HCNH+ (precursor of HCN and HNC) toward a galaxy, NGC4945, the abundance is much

  4. High Resolution Cl and S Isotope Analyses in Rocks and Minerals Using NanoSIMS

    NASA Astrophysics Data System (ADS)

    Kagoshima, T.; Takahata, N.; Ishida, A.; Sano, Y.

    2014-12-01

    We have developed highly spatial resolution isotope analysis with cycling magnetic fields on NanoSIMS 50 (Cameca, Gennevilliers, France) housed at Atmosphere and Ocean Research Institute, Japan. This technique requires two unmovable EM detectors (EM1 and EM2) and three magnetic fields (B1, B2, and B3). For Cl measurements, the following configuration was applied: (B1-EM1) 35Cl-; (B2-EM1) 37Cl-; (B2-EM2) 35Cl-; (B3-EM2) 37Cl-, in the form of "(B and EM configurations) target ions" (Table 1). When magnetic fields are in a cycling mode and moving next to next, we can obtain three isotopic ratios from the same spot: 37ClEM1/35ClEM1, 37ClEM2/35ClEM2, and 37ClEM1/35ClEM2 where subscripts show corresponding detectors. Considering the average of 37ClEM1/35ClEM1 and 37ClEM2/35ClEM2, reproducibility gets higher because total counts increase and analytical artifacts due to difference between detectors' sensitivity are offset. 10-μm spots were used for analyses. Reproducibility of 37Cl/35Cl in an apatite crystal from Imilchil/Errachidia region in Morroco was 1.1‰ (1σ; N=10), and that in RY380-R03b (EPR basalt: 17.4S, 113.2W) was 1.3‰ (1σ; N=8). These values may be small enough to evaluate aqueous alteration on mantle-derived materials because it causes 6‰ variation in reaction related reservoirs such as sediments and pore fluids[1]. There were no apparent correlations between Cl contents and 37Cl/35Cl in RY380-R03b, supporting that strong correlations between them found in MORB by a pyrohydrolysis method[2] may be analytical artifacts[1]. We also measured S isotope ratios based on the same method as Cl. 5-μm spots were used for analyses. Reproducibility of 34S/32S in a pyrite crystal from Udo mine in Japan[3] was 1.8‰ (1σ; N=6), and that in CH98 DR12 (MAR basalt: 30.1N, 41.9W) was 1.7‰ (1σ; N=5). These values are small enough to evaluate S fractionation or mixing in the basalt-seawater system which have 20‰ difference in δ34S. This technique will enable us

  5. Fractionation of sulfur isotopes during heterogeneous oxidation of SO2 on sea salt aerosol: a new tool to investigate non-sea salt sulfate production in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Harris, E.; Sinha, B.; Hoppe, P.; Foley, S.; Borrmann, S.

    2012-05-01

    The oxidation of SO2 to sulfate on sea salt aerosols in the marine environment is highly important because of its effect on the size distribution of sulfate and the potential for new particle nucleation from H2SO4 (g). However, models of the sulfur cycle are not currently able to account for the complex relationship between particle size, alkalinity, oxidation pathway and rate - which is critical as SO2 oxidation by O3 and Cl catalysis are limited by aerosol alkalinity, whereas oxidation by hypohalous acids and transition metal ions can continue at low pH once alkalinity is titrated. We have measured 34S/32S fractionation factors for SO2 oxidation in sea salt, pure water and NaOCl aerosol, as well as the pH dependency of fractionation. Oxidation of SO2 by NaOCl aerosol was extremely efficient, with a reactive uptake coefficient of ≈0.5, and produced sulfate that was enriched in 32S with αOCl = 0.9882±0.0036 at 19 °C. Oxidation on sea salt aerosol was much less efficient than on NaOCl aerosol, suggesting alkalinity was already exhausted on the short timescale of the experiments. Measurements at pH = 2.1 and 7.2 were used to calculate fractionation factors for each step from SO2(g) → multiple steps → SOOCl2-. Oxidation on sea salt aerosol resulted in a lower fractionation factor than expected for oxidation of SO32- by O3 (αseasalt = 1.0124±0.0017 at 19 °C). Comparison of the lower fractionation during oxidation on sea salt aerosol to the fractionation factor for high pH oxidation shows HOCl contributed 29% of S(IV) oxidation on sea salt in the short experimental timescale, highlighting the potential importance of hypohalous acids in the marine environment. The sulfur isotope fractionation factors measured in this study allow differentiation between the alkalinity-limited pathways - oxidation by O3 and by Cl catalysis (α34 = 1.0163±0.0018 at 19 °C in pure water or 1.0199±0.0024 at pH = 7.2) - which favour the heavy isotope, and the alkalinity non

  6. Fractionation of sulfur isotopes during heterogeneous oxidation of SO2 on sea salt aerosol: a new tool to investigate non-sea salt sulfate production in the marine boundary layer

    NASA Astrophysics Data System (ADS)

    Harris, E.; Sinha, B.; Hoppe, P.; Foley, S.; Borrmann, S.

    2012-01-01

    The oxidation of SO2 to sulfate on sea salt aerosols in the marine environment is highly important because of its effect on the size distribution of sulfate and the potential for new particle nucleation from H2SO4 (g). However, models of the sulfur cycle are not currently able to account for the complex relationship between particle size, alkalinity, oxidation pathway and rate - which is critical as SO2 oxidation by O3 and Cl catalysis are limited by aerosol alkalinity, whereas oxidation by hypohalous acids and transition metal ions can continue at low pH once alkalinity is titrated. We have measured 34S/32S fractionation factors for SO2 oxidation in sea salt, pure water and NaOCl aerosol, as well as the pH dependency of fractionation, and demonstrated that sulfur isotopes can be effectively used to investigate the relative importance of different oxidation pathways in the marine boundary layer. Oxidation of SO2 by NaOCl aerosol was extremely efficient, with a reactive uptake coefficient of ~0.5, and produced sulfate that was enriched in 32S with αOCl = 0.9882 ± 0.0036 at 19 °C. Oxidation on sea salt aerosol was much less efficient than on NaOCl aerosol, suggesting alkalinity was already exhausted on the short timescale of the experiments. Measurements at pH = 2.1 and 7.2 were used to calculate fractionation factors for each step from SO2 (g) -> -> SO32-. Oxidation on sea salt aerosol resulted in a lower fractionation factor than expected for oxidation of SO32- by O3 (αseasalt = 1.0124 ± 0.0017 at 19 °C). Comparison of the lower fractionation during oxidation on sea salt aerosol to the fractionation factor for high pH oxidation shows HOCl contributed 29 % of S(IV) oxidation on sea salt in the short experimental timescale, highlighting the potential importance of hypohalous acids in the marine environment. The sulfur isotope fractionation factors measured in this study allow differentiation between the alkalinity-limited pathways - oxidation by O3 and by Cl

  7. Effect of biological contamination on dentine bond strength of adhesive resins.

    PubMed

    van Schalkwyk, J H; Botha, F S; van der Vyver, P J; de Wet, F A; Botha, S J

    2003-05-01

    The purpose of this in vitro study was to determine the effect of saliva (S) and blood (B) contamination on the dentine bond strength of two single-component dentine bonding systems. The occlusal thirds of 120 recently extracted, human molars were removed with a low speed saw and subsequently embedded in Bencor rings by means of self-curing, acrylic resin. The occlusal surfaces were ground wet on 600-grit silicone carbide paper in a polishing machine to expose superficial dentine and to create a smear layer. The teeth were randomly divided into 12 groups (n = 10). All the dentine surfaces were etched with 34% phosphoric acid for 15 seconds rinsed with water, air-dried for 3 seconds, leaving the surfaces visibly moist. For the control groups (C) the etched dentine surfaces were treated with either, Scotchbond 1 (SB1, 3M) or Prime & Bond NT (PBNT, Dentsply) according to the manufacturer's instructions. In the contaminated groups, the saliva or blood was applied by means of a disposable brush, left undisturbed for 1 minute, and the excess then thinned by air spray. The dentine bonding systems were then applied, also according to manufacturer's instructions. Composite (Z250 and TPH) and Compomer (F2000 and Dyract AP (D-AP)) stubs were packed and cured incrementally to the corresponding pretreated dentine surfaces. All specimens were stored for 24 hours under water at 37 degrees C. The bonds were then stressed to failure with a Zwick testing machine, operating at a crosshead speed of 0.5 mm/min. Fractured samples were examined in a Scanning Electron Microscope. The data were statistically analysed (Student-t test). The mean SBS (MPa) were. SB1 with Z250: C = 19.1 +/- 4.4; S = 17.3 +/- 3.5; B = 2.6 +/- 0.9; SB1 with F2000: C = 11.8 +/- 3.3; S = 9.7 +/- 1.8; B = 4.7 +/- 1.6. PBNT with TPH: C = 9.2 +/- 3.2; S = 6.5 +/- 3.0; B = 4.3 +/- 1.5; PBNT with D-AP: C = 10.2 +/- 3.6; S = 9.3 +/- 2.9 and B = 7.3 +/- 2.5. There was no statistical significant difference in shear bond strengths between the control and the saliva-contaminated samples for both systems. There was, however, a significant difference in bond strengths between the control and the blood-contaminated samples. Blood contamination negatively influenced bond strength of bonding systems to dentine. PMID:13677688

  8. Isotope geochemistry of the Amazon Basin: A reconnaissance

    SciTech Connect

    Longinelli, A.; Edmond, J.M.

    1983-04-20

    On the transects of the Amazon River made by the Alpha Helix in 1976 and 1977, an extensive suite of samples was collected for isotopic analyses. The water isotopes (/sup 18/O//sup 16/O, D/H) were determined in atmospheric water vapour and in river, rain, and leaf waters. /sup 13/C//sup 12/C ratios were measured in the dissolved and atmospheric CO/sub 2/. Determinations were made of /sup 34/S//sup 32/S and oxygen isotopes in dissolved sulphate. The effect of 'continentality' on the water isotopes is minor reflecting the large scale recycling by evapotranspiration from the huge area of forest within the basin. Variations in the isotopic abundances between 1976 (June--July, dry season) and 1977 (May--June, end of wet season) are consistent with the changes in meteorological conditions. The isotopic composition of the CO/sub 2/, both atmospheric and dissolved, is dominated by biological effects. In 1976 the dissolved CO/sub 2/ showed downstream variations from -14X at Iquitos in Peru to -22X in the lower reaches. In 1977, no systematic trend was apparent, the data ranging around -19X. The values for atmospheric CO/sub 2/ decrease inland from marine values at the mouth to around -15X at Manaus. During the dry season (1976) the values in the interior, western basin were homogeneous at -20X. In the wet season there were considerable variations reflecting atmospheric instabilities with the average value being about -13X. The sulphur isotopic composition of the dissolved sulphate is remarkably uniform at around 7X. In 1977 the /sup 18/O values in the sulphate decreased systematically downstream from 8X in Peru to 3X at the mouth, consistent with a progressive redox-mediated exchange with water and dissolved oxygen. In 1977 the values increased to over 11X, apparently indicating exchange with a highly fractionated reservoir of dissolved oxygen perhaps in the semireducing environment of the flood plain lakes.

  9. Multi-material 3-D viscoelastic model of a transtibial residuum from in-vivo indentation and MRI data.

    PubMed

    Sengeh, David M; Moerman, Kevin M; Petron, Arthur; Herr, Hugh

    2016-06-01

    Although the socket is critical in a prosthetic system for a person with limb amputation, the methods of its design are largely artisanal. A roadblock for a repeatable and quantitative socket design process is the lack of predictive and patient specific biomechanical models of the residuum. This study presents the evaluation of such a model using a combined experimental-numerical approach. The model geometry and tissue boundaries are derived from magnetic resonance imaging (MRI). The soft tissue non-linear elastic and viscoelastic mechanical behavior was evaluated using inverse finite element analysis (FEA) of in-vivo indentation experiments. A custom designed robotic in-vivo indentation system was used to provide a rich experimental data set of force versus time at 18 sites across a limb. During FEA, the tissues were represented by two layers, namely the skin-adipose layer and an underlying muscle-soft tissue complex. The non-linear elastic behavior was modeled using 2nd order Ogden hyperelastic formulations, and viscoelasticity was modeled using the quasi-linear theory of viscoelasticity. To determine the material parameters for each tissue, an inverse FEA based optimization routine was used that minimizes the combined mean of the squared force differences between the numerical and experimental force-time curves for indentations at 4 distinct anatomical regions on the residuum. The optimization provided the following material parameters for the skin-adipose layer: [c=5.22kPam=4.79γ=3.57MPaτ=0.32s] and for the muscle-soft tissue complex [c=5.20kPam=4.78γ=3.47MPaτ=0.34s]. These parameters were evaluated to predict the force-time curves for the remaining 14 anatomical locations. The mean percentage error (mean absolute error/ maximum experimental force) for these predictions was 7±3%. The mean percentage error at the 4 sites used for the optimization was 4%. PMID:26946095

  10. Experimentally determined sulfur isotope fractionation between metal and silicate and implications for planetary differentiation

    NASA Astrophysics Data System (ADS)

    Labidi, J.; Shahar, A.; Le Losq, C.; Hillgren, V. J.; Mysen, B. O.; Farquhar, J.

    2016-02-01

    The Earth's mantle displays a subchondritic 34S/32S ratio. Sulfur is a moderately siderophile element (i.e. iron-loving), and its partitioning into the Earth's core may have left such a distinctive isotope composition on the terrestrial mantle. In order to constrain the sulfur isotope fractionation occurring during core-mantle differentiation, high-pressure and temperature experiments were conducted with synthetic mixtures of metal and silicate melts. With the purpose to identify the mechanism(s) responsible for the S isotope fractionations, we performed our experiments in different capsules - namely, graphite and boron nitride capsules - and thus at different fO2, with varying major element chemistry of the silicate and metal fractions. The S isotope fractionations Δ34Smetal-silicate of equilibrated metal alloys versus silicate melts is +0.2 ± 0.1‰ in a boron-free and aluminum-poor system quenched at 1-1.5 GPa and 1650 °C. The isotope fractionation increases linearly with increasing boron and aluminum content, up to +1.4 ± 0.2‰, and is observed to be independent of the silicon abundance as well as of the fO2 over ∼3.5 log units of variations explored here. The isotope fractionations are also independent of the graphite or nitride saturation of the metal. Only the melt structural changes associated with aluminum and boron concentration in silicate melts have been observed to affect the strength of sulfur bonding. These results establish that the structure of silicate melts has a direct influence on the S2- average bonding strengths. These results can be interpreted in the context of planetary differentiation. Indeed, the structural environments of silicate evolve strongly with pressure. For example, the aluminum, iron or silicon coordination numbers increase under the effect of pressure. Consequently, based on our observations, the sulfur-bonding environment is likely to be affected. In this scheme, we tentatively hypothesize that S isotope fractionations

  11. Formation and resulfidization of a South Texas roll-type uranium deposit

    USGS Publications Warehouse

    Goldhaber, Martin B.; Reynolds, Richard L.; Rye, Robert O.

    1979-01-01

    Core samples from a roll type uranium deposit in Live Oak County, south Texas have been studied and results are reported for Se, Mo, FeS2 and organic-carbon distribution, sulfide mineral petrology, and sulfur isotopic composition of iron-disulfide phases. In addition, sulfur isotopic compositions of dissolved sulfate and sulfide from the modern ground water within the ore bearing sand have been studied. The suite of elements in the ore sand and their geometric relationships throughout the deposit are those expected for typical roll-type deposits with well-developed oxidation-reduction interfaces. However, iron-disulfide minerals are abundant in the altered tongue, demonstrating that this interval has been sulfidized after mineralization (resulfidized or rereduced). Iron disulfide minerals in the rereduced interval differ mineralogically and isotopically from those throughout the remainder of the deposit. The resulfidized sand contains dominantly pyrite that is enriched in 34S, whereas the sand beyond the altered tongue contains abundant marcasite that is enriched in the light isotope, 32S. Textural relationships between pyrite and marcasite help to establish relative timing of iron disulfide formation. In reduced rock outside the altered tongue, three distinct generations of iron disulfide are present. The oldest of these generations consists largely of pyrite with lesser amounts of marcasite. A major episode of marcasite formation contemporaneous with ore genesis postdates the oldest pyrite generation but predates a younger pyrite generation. Resulfidization probably led to the final pyrite stage recognized beyond the altered tongue. Stable isotope data establish that the source of sulfur for the resulfidization was fault-leaked H2S probably derived from the Edwards Limestone of Cretaceous age which underlies the deposit. The deposit formed in at least two stages: (1) a pre-ore process of host rock sulfidization which produced disseminated pyrite as the dominant

  12. Mineralogical and Sulfur Isotopic Study on Volcanic Ash of the 2014 Eruption at Ontake Volcano, Central Honshu, Japan

    NASA Astrophysics Data System (ADS)

    Imura, T.; Minami, Y.; Ohba, T.; Takahashi, R.; Imai, A.; Hayashi, S.

    2015-12-01

    Ontake volcano erupted on 27th September 2014. Components in fallout samples were analyzed with microscope, XRD, and SEM-EDS. Pyrophyllite, smectite, muscovite, kaoline group minerals, quartz, cristobalite, tridymite, pyrite, alunite, gypsum and anhydrite were identified from bulk samples. Coarse ash fraction (> 125 µm) consists mainly of siliceous fragments that are intensely altered and contain pyrite and rutile. Weakly-altered dark-gray volcanic rock fragments are also contained. Fine fraction is abundant in euhedral free crystals of alunite and gypsum and aggregates of silica minerals. The 34S/32S ratios of bulk ash samples were analyzed for sulfur leached by water (water-soluble sulfate), gastric (HCl-soluble sulfate), and HNO3 (sulfide). Gastric and HNO3 leaching methods were applied to coarse fraction too. The bulk δ34SCDT compositions of water-soluble sulfate, HCl-soluble sulfate and sulfide were +14.7 ‰, +15.7 ‰, and -4.7 ‰, respectively. Those of HCl-soluble sulfate and sulfide in coarse fraction were +9.1 ‰ and -4.3 ‰, respectively. Paragenesis of quartz and pyrophyllite in single grain implies hydrothermal alteration by hot (> 230 °C), acidic fluid in the sub-volcanic system. The sulfur isotope geothermometry (Ohmoto and Rye, 1979) applied to the pair of water-soluble sulfate and bulk sulfide resulted in 306 °C. Similar temperature (ca. 296 °C) was estimated for the pair of HCl-soluble sulfate and sulfide in bulk ash. The mineralogy and sulfur isotopic study indicate that the 2014 Ontake eruption was derived from an acidic high-temperature (ca. 300 °C) sub-volcanic hydrothermal fluid. However, the estimated temperature for the pair of HCl-soluble sulfate and sulfide from coarse fraction resulted in higher temperature (ca. 482 °C). The coarse fraction preserved the past temperature record of the hydrothermal fluid, because the coarse lithic fragments were derived from pre-existing altered rocks.

  13. Gusev-Meridiani-Type Soil Component Dissolved in Some Shock Glasses in Shergottites

    NASA Technical Reports Server (NTRS)

    Ross, D. K.; Rao, M. N.; Nyquist, L. E.; Shi, C. Y.; Sutton, S.; Harrison, D. H.

    2015-01-01

    Modal analysis, based on APXS, MiniTES and Mossbauer results obtained at Gusev and Meridiani sites on Mars, indicates that Martian soils consist predominantly of igneous minerals such as olivine, pyroxene and feldspar (approximately70 - 80%), with the balance consisting of alteration minerals such as sulfates, silica and chlorides]. These studies also showed that soil alteration did not occur in-situ and igneous and alteration components are derived from different sources. Below, we analyse the chemical abundance data obtained from shock glasses in shergottites using mass balance mixing models. In these models, the two main end members used are (a) host rock chemical composition and (b) the GM soils average composition as the second component. Here, we consider the S-bearing phases as indicators of added alteration phases in the shock glasses and GM soils. Although the S-bearing phase in shock glasses occurs as micron sized sulfide blebs, we showed in earlier abstracts that sulfur was originally present as sulfate in impact glass-precursor materials and was subsequently reduced to sulfide during shock melting. This conclusion is based on results obtained from S-K XANES studies, Fe/S atomic ratios in sulfide blebs and 34S/32S isotopic measurements in these sulfide blebs. Additionally, sulfur in several EET79001 Lith. A glasses is found to correlate positively with Al2O3 and CaO (and negatively with FeO and MgO), suggesting the presence of Al- and Ca- sul-fate-bearing phases. The distribution of the 87Sr/86Sr iso-topic ratios determined in Lith. A glasses (,27 &,188 and,54) indicate that Martian soil gypsum and host rock material were mixed with each other in the glass precursors. In some vugs in Lith A glass,27 detected gypsum laths. Furthermore, the Martian regolith-de-rived component (where sulfur typically occurs as sul-fate) is identified in these glasses by determining neutron produced isotopic excesses/deficits in 80Kr and 149Sm isotopes. Moreover, the

  14. A Coordinated Research Project on the Implementation of Nuclear Techniques to Improve Food Traceability

    NASA Astrophysics Data System (ADS)

    Frew, Russell; Cannavan, Andrew; Zandric, Zora; Maestroni, Britt; Abrahim, Aiman

    2013-04-01

    coffee, the adulteration of milk with soy protein, chemical contamination of food products, and inhomogeneity in isotopic ratios in poultry and eggs as a means to determine production history. Analytical techniques include stable isotope ratio measurements (2H/1H, 13C/12C, 15N/14N, 18O/16O, 34S/32S, 87Sr/86Sr, 208Pb/207Pb/206Pb), elemental analysis, DNA fingerprinting, fatty acid and other biomolecule profiling, chromatography-mass spectrometry and near infra-red spectroscopy.

  15. High-resolution Reconstruction of a Holocene Coastal Sequence (NW Germany) Using Inorganic Geochemical Data and Diatom Inventories

    NASA Astrophysics Data System (ADS)

    Dellwig, O.; Watermann, F.; Brumsack, H.-J.; Gerdes, G.

    1999-06-01

    Holocene deposits of the NW German coastal plain consist of many different lithological facies, for example tidal flats, brackish water sediments and peat beds. The effects of the Holocene sea-level rise on palaeoenvironmental conditions of this coastal sequence were studied by inorganic geochemical methods in conjunction with diatom analyses. Three hundred samples from two parallel sediment cores which cover the entire NW German Holocene were taken at high resolution and were examined for major and minor elements and bulk parameters. Selected samples were analysed for redox-sensitive trace elements and REE distribution, reactive iron and bulk sediment 34S/ 32S-ratios. Chemical parameters, for example Si/Al and Ca/Sr-ratios and total organic carbon (TOC) contents correlate with depositional factors such as wave-energy and lithofacies changes, which allow a detailed reconstruction of the palaeoenvironment. Diatom analyses reveal information about changes between marine, brackish and limnic conditions and serve to reconstruct palaeosalinity. Early diagenetic effects are evident in the TOC-rich intervals. Most peat layers are affected by sulphate reduction and resulting pyrite formation as well as by enrichments in redox-sensitive trace elements. The highest enrichments are seen for As, Mo, Re and U, indicating a distinct seawater influence. S-isotope ratios of peat samples are compatible with pyrite formation under both open- and closed-system conditions, depending on exposition to seawater. The inorganic geochemical and diatom data suggest limnic conditions at the base of the sequence and repeated changes towards marine conditions within the overlying clastic units. On the other hand, data obtained from the clastic units yield evidence of a recurrent succession from open to restricted marine, brackish-lagoonal, and finally fen environments. Clastic sediments overlying peat layers, correlate with the increase of marine-derived geochemical signatures and pelagic

  16. Major and trace-element analyses of acid mine waters in the Leviathan Mine drainage basin, California/Nevada; October, 1981 to October, 1982

    USGS Publications Warehouse

    Ball, J.W.; Nordstrom, D.K.

    1985-01-01

    Water issuing from the inactive Leviathan open-pit sulfur mine has caused serious degradation of the water quality in the Leviathan/Bryant Creek drainage basin which drains into the East Fork of the Carson River. As part of a pollution abatement project of the California Regional Water Quality Control Board, the U.S. Geological Survey collected hydrologic and water quality data for the basin during 1981-82. During this period a comprehensive sampling survey was completed to provide information on trace metal attenuation during downstream transport and to provide data for interpreting geochemical processes. This report presents the analytical results from this sampling survey. Sixty-seven water samples were filtered and preserved on-site at 45 locations and at 3 different times. Temperature, discharge, pH, and Eh and specific conductance were measured on-site. Concentrations of 37 major and trace constituents were determined later in the laboratory on preserved samples. The quality of the analyses was checked by using two or more techniques to determine the concentrations including d.c.-argon plasma emission spectrometry (DCP), flame and flameless atomic absorption spectrophotometry, UV-visible spectrophotometry, hydride-generation atomic absorption spectrophotometry and ion chromatography. Additional quality control was obtained by comparing measured to calculated conductance, comparing measured to calculated Eh (from Fe-2 +/Fe-3+ determinations), charge balance calculations and mass balance calculations for conservative constituents at confluence points. Leviathan acid mine waters contain mg/L concentrations of As, Cr, Co, Cu, Mn, Ni, T1, V and Zn, and hundreds to thousands of mg/L concentrations of Al, Fe, and sulfate at pH values as low as 1.8. Other elements including Ba, B, Be, Bi, Cd , Mo, Sb, Se and Te are elevated above normal background concentrations and fall in the microgram/L range. The chemical and 34 S/32 S isotopic analyses demonstrate that these

  17. The biogeochemistry, stable isotope geochemistry, and microbial community structure of a temperate intertidal mudflat: an integrated study

    NASA Astrophysics Data System (ADS)

    Böttcher, Michael E.; Hespenheide, Britta; Llobet-Brossa, Enrique; Beardsley, Christine; Larsen, Ole; Schramm, Andreas; Wieland, Andrea; Böttcher, Gerd; Berninger, Ulrike-G.; Amann, Rudolf

    2000-09-01

    the measured sulfate reduction rates and ranged between 0.06 and 0.55 fmol SO 42- cell -1 day -1 which is at the lower end determined for pure cultures. From a comparison of cellular SRR and stable sulfur isotope ( 34S/ 32S) fractionation between coexisting dissolved pore water sulfate and sedimentary reduced sulfur species with laboratory studies a significant contribution of bacterial disproportionation reactions within the oxidative part of the sedimentary sulfur cycle is indicated.

  18. Ground-water and stream-water interaction in the Owl Creek basin, Wyoming

    USGS Publications Warehouse

    Ogle, K.M.

    1996-01-01

    Understanding of the interaction of ground-water and surface-water resources is vital to water management when water availability is limited.Inflow of ground water is the primary source ofwater during stream base flow. The water chemistry of streams may substantially be affected by that inflow of ground water. This report is part of a study to examine ground-water and surface-water interaction in the Owl Creek Basin, Wyoming, completed by the U.S. Geological Survey incooperation with the Northern Arapaho Tribe and the Shoshone Tribe. During a low flow period between November\\x1113 - 17, 1991, streamflowmeasurements and water-quality samples were collected at 16 selected sites along major streams and tributaries in the Owl Creek Basin,Wyoming. The data were used to identify stream reaches receiving ground-water inflow and to examine causes of changes in stream chemistry.Streamflow measurements, radon-222 activity load, and dissolved solids load were used to identified stream reaches receiving ground-water inflow.Streamflow measurements identified three stream reaches receiving ground-water inflow. Analysis of radon-222 activity load identified five stream reaches receiving ground-water inflow. Dissolvedsolids load identified six stream reaches receiving ground-water inflow. When these three methods were combined, stream reaches in two areas, theEmbar Area and the Thermopolis Anticline Area, were identified as receiving ground-water inflow.The Embar Area and the Thermopolis Anticline Area were then evaluated to determine the source of increased chemical load in stream water. Three potential sources were analyzed: tributary inflow, surficial geology, and anticlines. Two sources,tributary inflow and surficial geology, were related to changes in isotopic ratios and chemical load in the Embar Area. In two reaches in the Embar Area, isotopic ratios of 18O/16O, D/H, and 34S/32S indicated that tributary inflow affected stream-water chemistry. Increased chemical load of

  19. Calculation of the properties of the S3- radical anion and its complexes with Cu+ in aqueous solution

    NASA Astrophysics Data System (ADS)

    Tossell, J. A.

    2012-10-01

    A species observed in aqueous sulfidic solutions at high T and P has recently been identified as the anion radical S3-, based on the Raman spectrum obtained in a hydrothermal diamond-anvil cell (Pokrovski and Dubrovinsky, 2011, Science, 331, 1052-1054). Such a species had not been expected to occur in such environments, although S3- as an component of lapis lazuli, other solids and even albite melt has been well studied (Winther et al., 1998; Reinen and Lindner, 1999; Arieli et al., 2004; Shnitko et al., 2008; Bacci et al., 2009). We have calculated the structures, energetics, vibrational and UV-visible spectra of S3- and several other similar species and confirm the species identification of Pokrovski and Dubrovinsky, although we are still somewhat concerned about the apparent lack of a third peak which we calculate to be present in the Raman spectrum of S3-. Our calculations indicate that the reaction: S6-2⇒2S3- in aqueous solution has a free energy change of +3 kcal/mol at 298 K and 1 atm pressure but -13 kcal/mol at 723 K and 1 atm pressure, consistent with the disappearance of disulfide species and the appearance of S3-at high T. Likewise, the free energy for the reaction: 2HS+SO4-2+H⇒S3-+.75O+2.5HO decreases from 44.1 to 19.0 kcal/mol between 298 and 723 K (again at 1 atm). This is consistent with the decrease in concentrations of SH- and SO4-2 and the formation of S3- observed by Pokrovski and Dubrovinski over this temperature range. The corresponding log K values are in semiquantitative agreement with those found by Pokrovski and Dubrovinsky. The main contribution to these changes in reaction free energy with temperature come from the VRT (vibrational-rotational-translational) contribution to the gas-phase free energy, while the hydration free energy difference changes little. Calculation of 34S-32S isotopic fractionations for S3- at 298 K give δ values of around +4.3% relative to H2S, a value intermediate between that of S3 and S3-2. Calculated free

  20. Geochemistry of sulfur in the Florida Everglades; 1994 through 1999

    USGS Publications Warehouse

    Bates, Anne L.; Orem, W.H.; Harvey, J.W.; Spiker, E. C.

    2000-01-01

    In this report, we present data on the geochemistry of sulfur in sediments and in surface water, groundwater, and rainwater in the Everglades region in south Florida. The results presented here are part of a larger study intended to determine the roles played by the cycling of carbon, nitrogen, phosphorus, and sulfur in the ecology of the south Florida wetlands. The geochemistry of sulfur in the region is particularly important because of its link to the production of toxic methylmercury through processes mediated by sulfate reducing bacteria. Sediment cores were collected from the Everglades Agricultural Area (EAA), Water Conservation Areas (WCAs) 1A and 2A, from Lake Okeechobee, and from Taylor Slough in the southern Everglades. Water collection was more widespread and includes surface water from WCAs 1A, 2A, 3A, 2B, the EAA, Taylor Slough, Lake Okeechobee, and the Kissimmee River. Groundwater was collected from The Everglades Nutrient Removal Area (ENR) and from WCA 2A. Rainwater was collected at two month intervals over a period of one year from the ENR and from WCA 2A. Water was analyzed for sulfate concentration and sulfate sulfur stable isotopic ratio (34S/32S). Sediment cores were analyzed for total sulfur concentration and/or for concentrations of sulfur species (sulfate, organic sulfur, disulfides, and acid volatile sulfides (AVS)) and for their stable sulfur isotopic ratio. Results show a decrease in total sulfur content (1.57 to 0.61 percent dry weight) with depth in two sediment cores collected in WCA 2A, indicating that there has been an increase in total sulfur content in recent times. A sediment core from the center of Lake Okeechobee shows a decrease in total sulfur content with depth (0.28 to 0.08 percent dry weight). A core from the periphery of the lake (South Bay) likewise shows a decrease in total sulfur content with depth (1.00 to 0.69 percent dry weight), however, the overall sulfur content is greater than that near the center at all depths

  1. MC32 tumor cells acquire Ag-specific CTL resistance through the loss of CEA in a colon cancer model

    PubMed Central

    Lee, Sang-Yeul; Sin, Jeong-Im

    2015-01-01

    We previously reported that MC32 cells resist carcinoembryonic antigen (CEA) DNA vaccination by losing their antigen presentation to Ag-specific CTLs in the context of MHC class I antigens in a colon cancer therapeutic model. In this study, we selected 2 tumor cells, MC32-S2–2 and MC32-S4–2, which have the ability to form tumors in CEA DNA vaccine-immunized mice. Wild type MC32 cells grew significantly less in CEA-immunized mice (with Ag-specific CTL lytic activity) than in control mice (with no Ag-specific CTL lytic activity). However, MC32-S2–2 and MC32-S4–2 cells grew at a similar rate in both control and CEA-immunized mice, confirming their resistant status against CEA DNA vaccination. MC32-S2–2 and MC32-S4–2 cells were not susceptible to lysis by CEA-specific CD8+ T cells. Moreover, when MC32-S2–2 and MC32-S4–2 cells were used as stimulating agents of CEA-specific immune cells for IFN-γ production, these cells failed to stimulate the induction of Ag-specific IFN-γ, suggesting a loss of tumor cell recognition by Ag-specific immune cells. However, MC32-S2–2 and MC32-S4–2 cells expressed MHC class I antigens in a manner similar to that of wild type MC32 cells. Finally, Western blot assay confirmed that in MC32-S2–2 and MC32-S4–2 cells, CEA expression remained absent but mouse CEA was expressed. Taken together, these data show that MC32 cells may also be able to achieve resistance to CEA-specific CTLs by antigen loss in this model. PMID:25902414

  2. Response Allocation in Concurrent Chains when Terminal-Link Delays Follow an Ascending and Descending Series

    ERIC Educational Resources Information Center

    Christensen, Darren R.; Grace, Randolph C.

    2009-01-01

    Eight pigeons were trained in a concurrent-chains procedure in which the terminal-link immediacy ratio followed an ascending or descending series. Across sessions, one terminal-link delay changed from 2 s to 32 s to 2 s or from 32 s to 2 s to 32 s, while the other was always 8 s. For all pigeons, response allocation tracked changes in delay and…

  3. Neoarchean carbonate-associated sulfate records positive Δ³³S anomalies.

    PubMed

    Paris, G; Adkins, J F; Sessions, A L; Webb, S M; Fischer, W W

    2014-11-01

    Mass-independent fractionation of sulfur isotopes (reported as Δ(33)S) recorded in Archean sedimentary rocks helps to constrain the composition of Earth's early atmosphere and the timing of the rise of oxygen ~2.4 billion years ago. Although current hypotheses predict uniformly negative Δ(33)S for Archean seawater sulfate, this remains untested through the vast majority of Archean time. We applied x-ray absorption spectroscopy to investigate the low sulfate content of particularly well-preserved Neoarchean carbonates and mass spectrometry to measure their Δ(33)S signatures. We report unexpected, large, widespread positive Δ(33)S values from stratigraphic sections capturing over 70 million years and diverse depositional environments. Combined with the pyrite record, these results show that sulfate does not carry the expected negative Δ(33)S from sulfur mass-independent fractionation in the Neoarchean atmosphere. PMID:25378622

  4. Sulfur isotopic composition of surface snow along a latitudinal transect in East Antarctica

    NASA Astrophysics Data System (ADS)

    Uemura, Ryu; Masaka, Kosuke; Fukui, Kotaro; Iizuka, Yoshinori; Hirabayashi, Motohiro; Motoyama, Hideaki

    2016-06-01

    The sulfur stable isotopic values (δ34S) of sulfate aerosols can be used to assess oxidation pathways and contributions from various sources, such as marine biogenic sulfur, volcanoes, and sea salt. However, because of a lack of observations, the spatial distribution of δ34S values in Antarctic sulfate aerosols remains unclear. Here we present the first sulfur isotopic values from surface snow samples along a latitudinal transect in eastern Dronning Maud Land, East Antarctica. The δ34S values of sulfate showed remarkably uniform values, in the range of 14.8-16.9‰, and no significant decrease toward the inland part of the transect was noted. These results suggest that net isotopic fractionation during long-range transport is insignificant. Thus, the δ34S values can be used to infer source contributions. The δ34S values suggest that marine biogenic sulfur is the dominant source of sulfate aerosols, with a fractional contribution of 84 ± 16%.

  5. Relationship between isotope composition of sulphur in sulphate dissolved in river water and sulphur extracted from fish scales.

    PubMed

    Trembaczowski, Andrzej; Niezgoda, Halina

    2011-06-01

    More than 100 trouts captured in more than 20 rivers from Poland have been analysed. Only fish caught by trout fishermen were used for this study. Isotope compositions of sulphur (δ(34)S) and carbon (δ(13)C) of fish scales were examined together with δ(34)S from sulphate dissolved in river, as well as patterns of fish diet. We predominantly examined adult fish, at least 4 years old. A scatter of isotope values occurred among the samples obtained from fish caught in different rivers and also for fish caught in the same river. The scatter of the δ(34)S values was much larger than that of δ(13)C values. We noticed the relationship between δ(34)S of scales and δ(34)S of riverine sulphate. There is also a significant difference between isotope compositions obtained for different fish species, which can be attributed to their different diet. PMID:21644133

  6. Global Neoproterozoic (Sturtian) post-glacial sulfide-sulfur isotope anomaly recognised in Namibia

    NASA Astrophysics Data System (ADS)

    Gorjan, Paul; Walter, Malcolm R.; Swart, Roger

    2003-02-01

    The Neoproterozoic Earth experienced at least two, probably global, glaciations. Each glaciation was superceded by deposition of a layer of carbonate ('cap-carbonate') that has a distinctive lithology and depletion in 13C ( δ13C carbonate ˜ -5‰). The ˜700 Ma Sturtian glaciation is followed by deposition of a cap-carbonate and post-glacial succession which contain bacterially produced sulfides extremely enriched in 34S (average δ34S sulfide ˜ +30‰) with maximum values up to +60‰. This level of 34S enrichment in sulfides is unique to the Sturtian post-glacial succession and recognised in Australia, Canada, and China. In the Neoproterozoic of the Nama Basin, Namibia, the Gobabis Member is the basal unit of the Court Formation, which overlies the glacial Blaubeker Formation. δ13C carbonate analyses from the Gobabis Member range from -5.2 to -2.2‰ (average = -3.7‰; n = 10). δ34S sulfide ranges from +16.1 to +61.1‰ (average = +37.6‰; n = 8). These results are consistent with a Sturtian age for the Blaubeker Formation and overlying Gobabis Member, which have previously been interpreted as Sturtian. The sulfur isotopic results are comparable with δ34S sulfide in Sturtian post-glacial units of Australia, Canada and China. This adds to the evidence for correlation of the Blaubeker Formation with Sturtian glaciations on other continents. The cause of such elevated δ34S sulfide is enigmatic. Geochemical evidence suggests the sulfide was not formed from low sulfate waters nor in euxinic conditions, which discounts any known modern analogue. 34S enrichment in sulfides is therefore postulated to be caused by enrichment of 34S in contemporaneous seawater ( δ34S sulfate up to +60‰?). The rise in seawater δ34S sulfate is considered to be the result of intense bacterial sulfate reduction in an anoxic ocean during the Sturtian glaciation.

  7. Use of isotopic sulfur to determine whitebark pine consumption by Yellowstone bears: a reassessment

    USGS Publications Warehouse

    Schwartz, Charles C.; Teisberg, Justin E.; Fortin, Jennifer K.; Haroldson, Mark A.; Servheen, Christopher; Robbins, Charles T.; van Manen, Frank T.

    2014-01-01

    Use of naturally occurring stable isotopes to estimate assimilated diet of bears is one of the single greatest breakthroughs in nutritional ecology during the past 20 years. Previous research in the Greater Yellowstone Ecosystem (GYE), USA, established a positive relationship between the stable isotope of sulfur (δ34S) and consumption of whitebark pine (Pinus albicaulis) seeds. That work combined a limited sample of hair, blood clots, and serum. Here we use a much larger sample to reassess those findings. We contrasted δ34S values in spring hair and serum with abundance of seeds of whitebark pine in samples collected from grizzly (Ursus arctos) and American black bears (U. americanus) in the GYE during 2000–2010. Although we found a positive relationship between δ34S values in spring hair and pine seed abundance for grizzly bears, the coefficients of determination were small (R2 ≤ 0.097); we failed to find a similar relationship with black bears. Values of δ34S in spring hair were larger in black bears and δ34S values in serum of grizzly bears were lowest in September and October, a time when we expect δ34S to peak if whitebark pine seeds were the sole source of high δ34S. The relationship between δ34S in bear tissue and the consumption of whitebark pine seeds, as originally reported, may not be as clean a method as proposed. Data we present here suggest other foods have high values of δ34S, and there is spatial heterogeneity affecting the δ34S values in whitebark pine, which must be addressed.

  8. CHK1-driven histone H3.3 serine 31 phosphorylation is important for chromatin maintenance and cell survival in human ALT cancer cells.

    PubMed

    Chang, Fiona T M; Chan, F Lyn; R McGhie, James D; Udugama, Maheshi; Mayne, Lynne; Collas, Philippe; Mann, Jeffrey R; Wong, Lee H

    2015-03-11

    Human ALT cancers show high mutation rates in ATRX and DAXX. Although it is well known that the absence of ATRX/DAXX disrupts H3.3 deposition at heterochromatin, its impact on H3.3 deposition and post-translational modification in the global genome remains unclear. Here, we explore the dynamics of phosphorylated H3.3 serine 31 (H3.3S31ph) in human ALT cancer cells. While H3.3S31ph is found only at pericentric satellite DNA repeats during mitosis in most somatic human cells, a high level of H3.3S31ph is detected on the entire chromosome in ALT cells, attributable to an elevated CHK1 activity in these cells. Drug inhibition of CHK1 activity during mitosis and expression of mutant H3.3S31A in these ALT cells result in a decrease in H3.3S31ph levels accompanied with increased levels of phosphorylated H2AX serine 139 on chromosome arms and at the telomeres. Furthermore, the inhibition of CHK1 activity in these cells also reduces cell viability. Our findings suggest a novel role of CHK1 as an H3.3S31 kinase, and that CHK1-mediated H3.3S31ph plays an important role in the maintenance of chromatin integrity and cell survival in ALT cancer cells. PMID:25690891

  9. Evaluating the relationship between the carbon and sulfur cycles in the later Cambrian ocean: An example from the Port au Port Group, western Newfoundland, Canada

    NASA Astrophysics Data System (ADS)

    Hurtgen, Matthew T.; Pruss, Sara B.; Knoll, Andrew H.

    2009-05-01

    We present a high-resolution δ34S (sulfate and pyrite) and δ13C carbonate record from the Middle-Upper Cambrian Port au Port Group, a mixed carbonate-siliciclastic succession exposed in western Newfoundland, Canada. The results illustrate systematic δ34S sulfate shifts of > 15‰ over relatively short stratigraphic intervals (10 m, likely < 1 m.y.), low average Δ 34S sulfate-pyrite (ca. 23‰) and a generally positive coupling between changes in δ13C carbonate and δ34S sulfate. Together, these results indicate that Middle to Late Cambrian sulfate concentrations were low and that the sulfate reservoir was more sensitive to change than it was in either terminal Neoproterozoic or Cenozoic oceans. However, a simple carbon (C) and sulfur (S) isotope box model of the Late Cambrian ocean illustrates that low sulfate concentrations alone fail to account for the > 15‰ δ34S sulfate shifts recognized in Port au Port strata. Such large shifts can be generated only if fluctuating oceanic redox is invoked; marine anoxia forces reduced C/S burial and elevated Δ 34S, driving larger δ34S changes per mole of organic carbon buried. The conclusion that later Cambrian oceans featured both low sulfate levels and widespread subsurface anoxia supports hypotheses that link fluctuating marine redox conditions in the delayed recovery of skeletal animals and metazoan reefs from late Early Cambrian extinction.

  10. Sulfide formation in reservoir carbonates of the Devonian Nisku Formation, Alberta, Canada: An ion microprobe study

    SciTech Connect

    Riciputi, L.R.; Cole, D.R.; Machel, H.G.

    1996-01-01

    The processes affecting sulfur during diagenesis in carbonates have been investigated by ion microprobe analysis of {sigma} {sup 34}S values of pyrite, marcasite, and anhydrite from the Devonian Nisku Formation in the Western Canada Sedimentary Basin. Pyrite and marcasite from three Nisku wells have {sigma}{sup 34}S ranging between -35 and +20{per_thousand}. The {sigma}{sup 34}S values increase b6y up to 50{per_thousand} with increasing well depth in two different Nisku wells, and {sigma}{sup 34}S also increases by up to 15{per_thousand} as grain size increases form 40 to over 100 {mu}m in individual samples. The appearance of native sulfur is accompanied by an increase of up to 30{per_thousand} in pyrite {sigma}{sup 34}S values. Bulk and ion probe analyses of anhydrite are relatively uniform ({sigma}{sup 34}S = +22 to +30{per_thousand} CDT). The predominately low {sigma}{sup 34}S values of Nisku sulfides indicate bacterial sulfate reduction. Textural relations indicate that Fe-sulfide formation in Nisku carbonates may have occurred by two different mechanisms. Much of the sulfide has {sigma}{sup 34}S values that suggest that it was associated with bacterial sulfate reduction, although most Fe-sulfides did not form until after pervasive matrix dolomitization (depths of 300-1000 m). Other sulfide may have formed later, during deep ({approximately}4km) burial via thermochemical sulfate reduction. The range in {sigma}{sup 34}S values in a single thin section and correlations between pyrite morphology and isotopic values suggest that sulfate reduction was a very localized process, and that the sulfate reduction environment varied considerably on a small scale. 61 refs., 10 figs., 1 tab.

  11. Progression in sulfur isotopic compositions from coal to fly ash: Examples from single-source combustion in Indiana

    USGS Publications Warehouse

    Yaofa, Jiang; Elswick, E.R.; Mastalerz, Maria

    2008-01-01

    Sulfur occurs in multiple mineral forms in coals, and its fate in coal combustion is still not well understood. The sulfur isotopic composition of coal from two coal mines in Indiana and fly ash from two power plants that use these coals were studied using geological and geochemical methods. The two coal beds are Middle Pennsylvanian in age; one seam is the low-sulfur ( 5%) Springfield Coal Member of the Petersburg Formation. Both seams have ash contents of approximately 11%. Fly-ash samples were collected at various points in the ash-collection system in the two plants. The results show notable difference in ??34S for sulfur species within and between the low-sulfur and high-sulfur coal. The ??34S values for all sulfur species are exclusively positive in the low-sulfur Danville coal, whereas the ??34S values for sulfate, pyritic, and organic sulfur are both positive and negative in the high-sulfur Springfield coal. Each coal exhibits a distinct pattern of stratigraphic variation in sulfur isotopic composition. Overall, the ??34S for sulfur species values increase up the section in the low-sulfur Danville coal, whereas they show a decrease up the vertical section in the high-sulfur Springfield coal. Based on the evolution of ??34S for sulfur species, it is suggested that there was influence of seawater on peat swamp, with two marine incursions occurring during peat accumulation of the high-sulfur Springfield coal. Therefore, bacterial sulfate reduction played a key role in converting sulfate into hydrogen sulfide, sulfide minerals, and elemental sulfur. The differences in ??34S between sulfate sulfur and pyritic sulfur is very small between individual benches of both coals, implying that some oxidation occurred during deposition or postdeposition. The ??34S values for fly ash from the high-sulfur Springfield coal (averaging 9.7???) are greatly enriched in 34S relative to those in the parent coal (averaging 2.2???). This indicates a fractionation of sulfur isotopes

  12. Isotopic ratio and concentration of sulfur in the undersaturated alkaline magmas of Vulture Volcano (Italy)

    NASA Astrophysics Data System (ADS)

    Marini, L.; Paiotti, A.; Principe, C.; Ferrara, G.; Cioni, R.

    1994-12-01

    Both the δ34S value and the total S content of products from Vulture Volcano, Italy are mainly controlled by the separation of S gases, predominantly SO2, from high f O2 magmas containing S predominantly as SO2 4. The addition of evaporites to such magmas appears to be a relatively uncommon and limited phenomenon. The total S content of the most primitive product of Vulture Volcano (5600 mg/kg) is very high. The high δ34S value of 4ö indicates an origin through the partial melting of a mantle containing high S, enriched in 34S of unknown origin.

  13. Association of gold with uraninite and pyrobitumen in the metavolcanic rock hosted hydrothermal Au-U mineralisation at Rompas, Peräpohja Schist Belt, northern Finland

    NASA Astrophysics Data System (ADS)

    Molnár, Ferenc; Oduro, Harry; Cook, Nick D. J.; Pohjolainen, Esa; Takács, Ágnes; O'Brien, Hugh; Pakkanen, Lassi; Johanson, Bo; Wirth, Richard

    2016-06-01

    -ordered graphite in calcsilicate veins. Mean random reflectance data for pyrobitumen indicate 270-340 °C maximum temperature of thermal maturation—this temperature range is also considered as the temperature of gold deposition. Results of multiple sulphur isotope analyses of organic material-, pyrite- and acid-volatile-bound sulphur show distinct ranges of δ34S values for SORG and SCRS in uraninite-pyrobitumen (from -6.99 to -3.55‰ and from -10.02 to -4.41‰, respectively) and uraninite-pyrobitumen-native gold mineral associations (from +1.36 to +6.87‰ and from +0.42 to +9.7‰, respectively). Δ33S data indicate local occurrence of nonmass-dependent sulphur isotope fractionation owing to interaction of fluids with organic material. Concentration of lead in uraninite is depleted along the gold mineral filled fractures whereas the uranogenic lead isotope contents of galena, altaite and hunchuite deposited in the same fractures are extremely high, suggesting that the dominant source of lead for the crystallisation of these minerals was the radiogenic lead content of uraninite. Taking into account this source of radiogenic lead, the calculated Pb-Pb model ages for the lead minerals are between 1.75 and 1.70 Ga. Sulphur and tellurium removal from the fluid by reaction with radiogenic lead released by uraninite appears to be an important mechanism in the strongly localised deposition of gold minerals. Scavenging of sulphur by pyrobitumen nodules from gold transporting fluids was an additional process triggering precipitation of gold. Carbon particles and organic functional groups in pyrobitumen probably acted as nucleation and adsorption centres for gold minerals.

  14. Association of gold with uraninite and pyrobitumen in the metavolcanic rock hosted hydrothermal Au-U mineralisation at Rompas, Peräpohja Schist Belt, northern Finland

    NASA Astrophysics Data System (ADS)

    Molnár, Ferenc; Oduro, Harry; Cook, Nick D. J.; Pohjolainen, Esa; Takács, Ágnes; O'Brien, Hugh; Pakkanen, Lassi; Johanson, Bo; Wirth, Richard

    2016-01-01

    -ordered graphite in calcsilicate veins. Mean random reflectance data for pyrobitumen indicate 270-340 °C maximum temperature of thermal maturation—this temperature range is also considered as the temperature of gold deposition. Results of multiple sulphur isotope analyses of organic material-, pyrite- and acid-volatile-bound sulphur show distinct ranges of δ34S values for SORG and SCRS in uraninite-pyrobitumen (from -6.99 to -3.55‰ and from -10.02 to -4.41‰, respectively) and uraninite-pyrobitumen-native gold mineral associations (from +1.36 to +6.87‰ and from +0.42 to +9.7‰, respectively). Δ33S data indicate local occurrence of nonmass-dependent sulphur isotope fractionation owing to interaction of fluids with organic material. Concentration of lead in uraninite is depleted along the gold mineral filled fractures whereas the uranogenic lead isotope contents of galena, altaite and hunchuite deposited in the same fractures are extremely high, suggesting that the dominant source of lead for the crystallisation of these minerals was the radiogenic lead content of uraninite. Taking into account this source of radiogenic lead, the calculated Pb-Pb model ages for the lead minerals are between 1.75 and 1.70 Ga. Sulphur and tellurium removal from the fluid by reaction with radiogenic lead released by uraninite appears to be an important mechanism in the strongly localised deposition of gold minerals. Scavenging of sulphur by pyrobitumen nodules from gold transporting fluids was an additional process triggering precipitation of gold. Carbon particles and organic functional groups in pyrobitumen probably acted as nucleation and adsorption centres for gold minerals.

  15. Oscillator strengths and transition probabilities for allowed and forbidden transitions in Fe XIX

    SciTech Connect

    Nahar, Sultana N.

    2011-07-15

    An extensive set of oscillator strengths, line strengths, and radiative decay rates for the allowed and forbidden transitions in Fe XIX is presented. They correspond to 1626 fine structure levels of total angular momenta 0{<=}J{<=}8 of even and odd parities with 2{<=}n{<=}10, 0{<=}l{<=}9, 0{<=}L{<=}10, and (2S+1)=1, 3, 5. In contrast, the compiled table of the National Institute for Standards and Technology (NIST) lists only 63 observed levels. A total of 289,291 electric dipole allowed transitions are presented. They were obtained in the close coupling approximation using the relativistic Breit-Pauli R-matrix method. The wavefunction expansion included 15 levels of the configurations 2s{sup 2}2p{sup 3}, 2s2p{sup 4}, and 2p{sup 5} of the Fe XX core. The calculated fine structure levels are assigned with spectroscopic identifications using quantum defect analysis. Comparison with the observed energies shows very good agreement, the largest difference being less than 4%. The transitions also compare well with the compiled data by NIST and recent calculations. The forbidden transitions of the electric quadrupole and octupole, and magnetic dipole and quadrupole, type are presented for the 379 levels of the configurations 2s{sup 2}2p{sup 4}, 2s2p{sup 5}, 2p{sup 6}, 2s{sup 2}2p{sup 3}3s, 2s{sup 2}2p{sup 3}3p, 2s{sup 2}2p{sup 3}3d, 2s{sup 2}2p{sup 3}4s, 2s{sup 2}2p{sup 3}4p, 2s{sup 2}2p{sup 3}4d, 2s{sup 2}2p{sup 3}4f, 2s2p{sup 4}3s, 2s2p{sup 4}3p, 2s2p{sup 4}3d, 2s2p{sup 4}4s, 2s2p{sup 4}4p, and 2s{sup 2}2p{sup 2}3s{sup 2} of Fe XIX. They correspond to a total of 66,619 transitions. These results have been obtained from relativistic Breit-Pauli atomic structure calculations using the program SUPERSTRUCTURE. The forbidden transition probabilities show very good agreement with those compiled by NIST. - Highlights: {yields} Presents the most complete (n up to 10) set of transitions for Fe XIX. {yields} Considers both allowed and forbidden transitions. {yields} Large number of new energy levels are found. {yields} Benchmarks existing accurate energies and transitions. {yields} Completeness and accuracy are crucial to solve its abundance in the Sun.

  16. Stable sulphur isotope ratios in the moss species Hylocomium splendens (Hedw.) B.S.G. and Pleurozium schreberi (Brid.) Mitt. from the Kielce area (south-central Poland).

    PubMed

    Migaszewski, Zdzisław M; Dołegowska, Sabina; Hałas, Stanisław; Trembaczowski, Andrzej

    2010-06-01

    Stable sulphur isotope determinations were performed on 18 moss samples collected at nine sites in forested areas of the city of Kielce. The delta(34)S of Hylocomium splendens varied from 4.4 to 7.1 per thousand, whereas the delta(34)S of Pleurozium schreberi was in the range of 3.7-9.1 per thousand. The Holy Cross Mountains mosses display a positive delta(34)S signature of airborne SO(2) and sulphates of anthropogenic origin, which is characteristic for this part of Europe. Some spatial variations in the delta(34)S of mosses are due to the interactions that occur between coal combustion emissions with diverse isotopic imprints, variations in wind direction and topographic features combined with biological fractionation. PMID:20582790

  17. Application of sulphur isotope ratios to examine weaning patterns and freshwater fish consumption in Roman Oxfordshire, UK

    NASA Astrophysics Data System (ADS)

    Nehlich, Olaf; Fuller, Benjamin T.; Jay, Mandy; Mora, Alice; Nicholson, Rebecca A.; Smith, Colin I.; Richards, Michael P.

    2011-09-01

    This study investigates the application of sulphur isotope ratios (δ 34S) in combination with carbon (δ 13C) and nitrogen (δ 15N) ratios to understand the influence of environmental sulphur on the isotopic composition of archaeological human and faunal remains from Roman era sites in Oxfordshire, UK. Humans ( n = 83), terrestrial animals ( n = 11), and freshwater fish ( n = 5) were analysed for their isotope values from four locations in the Thames River Valley, and a broad range of δ 34S values were found. The δ 34S values from the terrestrial animals were highly variable (-13.6‰ to +0.5‰), but the δ 34S values of the fish were clustered and 34S-depleted (-20.9‰ to -17.3‰). The results of the faunal remains suggest that riverine sulphur influenced the terrestrial sulphur isotopic signatures. Terrestrial animals were possibly raised on the floodplains of the River Thames, where highly 34S-depleted sulphur influenced the soil. The humans show the largest range of δ 34S values (-18.8‰ to +9.6‰) from any archaeological context to date. No differences in δ 34S values were found between the males (-7.8 ± 6.0‰) and females (-5.3 ± 6.8‰), but the females had a linear correlation ( R2 = 0.71; p < 0.0001) between their δ 15N and δ 34S compositions. These δ 34S results suggest a greater dietary variability for the inhabitants of Roman Oxfordshire than previously thought, with some individuals eating solely terrestrial protein resources and others showing a diet almost exclusively based on freshwater protein such as fish. Such large dietary variability was not visible by analysing only the carbon and nitrogen isotope ratios, and this research represents the largest and most detailed application of δ 34S analysis to examine dietary practices (including breastfeeding and weaning patterns) during the Romano-British Period.

  18. The age curves of sulfur and oxygen isotopes in marine sulfate and their mutual interpretation

    USGS Publications Warehouse

    Claypool, George E.; Holser, William T.; Kaplan, Isaac R.; Sakai, Hitoshi; Zak, Israel

    1980-01-01

    Three hundred new samples of marine evaporite sulfate, of world-wide distribution, were analyzed for δ34S, and 60 of these also for δ18O in the sulfate ion. Detailed δ34S age curves for Tertiary—Cretaceous, Permian—Pennsylvanian, Devonian, Cambrian and Proterozoic times document large variations in δ34S. A summary curve forδ18O also shows definite variations, some at different times than δ34S, and always smaller. The measured δ34S and δ18O correspond to variations in these isotopes in sulfate of the world ocean surface. The variations of δ18O are controlled by input and output fluxes of sulfur in the ocean, three of which are the same that control δ34S: deposition and erosion of sulfate, and deposition of sulfide. Erosion of sulfide differs in its effect on the S and O systems. δ18O in the sulfate does not seem to be measurably affected by equilibration with either seawater or with subsurface waters after crystallization. In principle, the simultaneous application of both δ34S and δ18O age curves should help reduce the number of assumptions in calculations of the cycles of sulfur and oxygen through geological time, and a new model involving symmetrical fluxes is introduced here to take advantage of the oxygen data. However, all previously published models as well as this one lead to anomalies, such as unreasonable calcium or oxygen depletions in the ocean—atmosphere system. In addition, most models are incapable of reproducing the sharp rises of the δ34S curve in the late Proterozoic, the Devonian and the Triassic which would be the result of unreasonably fast net sulfide deposition. This fast depletion could result from an ocean that has not always been mixed (as previously assumed in all model calculations).

  19. Assessment of sulfate sources in high-elevation Asian precipitation using stable sulfur isotopes.

    PubMed

    Pruett, Lee E; Kreutz, Karl J; Wadleigh, Moire; Aizen, Vladimir

    2004-09-15

    Stable sulfur isotope measurements (delta34S) made on samples collected from a 2 m snowpit on the Inilchek Glacier, Tien Shan Mountains (42.16 degrees N, 80.25 degrees E, 5100 m) are used to estimate sources of sulfate (SO4(2-)) in high-elevation Central Asian precipitation. Comparison of snowpit oxygen isotope (delta18O) data with previous work constrains the age of the snowpit samples to the summer season during which they were retrieved (1999). Delta34S measurements were made at 10 cm resolution (20 samples total), with delta34S values ranging from 0.4/1000 during background ([SO4(2-)] < 1 microequiv L(-1)) periods to 19.4/1000 during a single high [SO4(2-)] event. On the basis of the significant correlation (r = 0.87) between [SO4(2-)] and delta34S values, coupled with major ion concentration time series and concentration ratios, we suggest a two-component mixing system consisting of evaporite dust and anthropogenic SO4(2-) to explain the observed delta34S values. Using a regression model, we estimate that during the 1999 summer season 60% of the deposited SO4(2-) was from an evaporite dust source, while 40% of the SO4(2-) was from anthropogenic sources. Due to the potentially large and unconstrained range of delta34S values for both evaporite and anthropogenic SO4(2-) sources in Asia, the error in our estimates is difficult to assess. However, the delta34S data from the 1999 Tien Shan snowpit provide the first unambiguous identification of evaporite and anthropogenic SO4(2-) in high-elevation Asian precipitation, and future ice core studies using improved analysis techniques and source delta34S values can provide detailed information on sulfur biogeochemistry and anthropogenic impacts in Asian alpine regions. PMID:15487779

  20. Origine du soufre associé aux minéralisations Pb-Zn de type Mississippi Valley de la chaîne des Beni Snassen orientaux (Maroc nord-oriental)

    NASA Astrophysics Data System (ADS)

    Bouabdellah, Mohammed; Boudchiche, Lahbib; Ouahhabi, Benali; Naciri, Tayeb

    2008-12-01

    Sulfur isotope data measured on samples of galena from the main Mississippi Valley-type prospects of the eastern Beni Snassen belt preclude an igneous source for sulfur, pointing instead to a sedimentary source. Negative δ 34S values are interpreted to being derived from bacteriogenic reduction of Jurassic seawater sulphate. Positive δ 34S values are considered to be hydrothermal sulfide transported with metal-bearing fluid. Mixing of these two fluids resulted in the deposition of the Pb ore.

  1. Fractionation of Sulfur Isotopes by Desulfovibrio vulgaris Mutants Lacking Periplasmic Hydrogenases or the Type I Tetraheme Cytochrome c3

    NASA Astrophysics Data System (ADS)

    Sim, M.; Ono, S.; Bosak, T.

    2012-12-01

    A large fraction of anaerobic mineralization of organic compounds relies on microbial sulfate reduction. Sulfur isotope fractionation by these microbes has been widely used to trace the biogeochemical cycling of sulfur and carbon, but intracellular mechanisms behind the wide range of fractionations observed in nature and cultures are not fully understood. In this study, we investigated the influence of electron transport chain components on the fractionation of sulfur isotopes by culturing Desulfovibrio vulgaris Hildenborough mutants lacking hydrogenases or type I tetraheme cytochrome c3 (Tp1-c3). The mutants were grown both in batch and continuous cultures. All tested mutants grew on lactate or pyruvate as the sole carbon and energy sources, generating sulfide. Mutants lacking cytoplasmic and periplasmic hydrogenases exhibited similar growth physiologies and sulfur isotope fractionations to their parent strains. On the other hand, a mutant lacking Tp1-c3 (ΔcycA) fractionated the 34S/32S ratio more than the wild type, evolving H2 in the headspace and exhibiting a lower specific respiration rate. In the presence of high concentrations of pyruvate, the growth of ΔcycA relied largely on fermentation rather than sulfate reduction, even when sulfate was abundant, producing the largest sulfur isotope effect observed in this study. Differences between sulfur isotope fractionation by ΔcycA and the wild type highlight the effect of electron transfer chains on the magnitude of sulfur isotope fractionation. Because Tp1-c3 is known to exclusively shuttle electrons from periplasmic hydrogenases to transmembrane complexes, electron transfers in the absence of Tp1-c3 should bypass the periplasmic hydrogen cycling, and the loss of reducing equivalents in the form of H2 can impair the flow of electrons from organic acids to sulfur, increasing isotope fractionation. Larger fractionation by ΔcycA can inform interpretations of sulfur isotope data at an environmental scale as well

  2. Pre-3.5 Ga terrestrial sediments as test cases in the search for life in the solar system

    NASA Astrophysics Data System (ADS)

    Mojzsis, S. J.

    2002-12-01

    The general approach to understanding the early development of life on Earth has been to establish the antiquity of rocks by identifying radiometrically dateable sequences containing morphologically classifiable fossils (morphofossils). While this approach has served us well for nearly a century, classical micropaleontological methods used to interpret the Proterozoic (2.5 - 0.54 Ga) record of life are unsatisfactory in studying the early Archean (>3.2 Ga) record, which has been obscured by metamorphism. To gather insights into earlier traces of life, we must see past the limitations of the morphofossil record and recognize the value of chemical fossils. One such approach has been to utilize the strong fractionation that metabolic activity of organisms imparts to light stable isotope ratios (13C/12C, 15N/14N, 34S/32S). The importance of such searches is that they provide a natural test bed for planning the kinds of analyses to be performed on samples returned from elsewhere, even if such searches have had mixed success in ancient terrestrial rocks. For example, the atmosphere, carbon products of mantle degassing and carbonate in water on Earth define the inorganic pool of carbon from which bioorganic carbon is isotopically fractionated. Mass balance calculations demonstrate that the average isotopic composition of terrestrial carbon is ~ δ13C = -6 ‰ and therefore typical metabolic fractionations from this starting value results in δ13C (biomass) < -27‰ . However, problems arise when applying the assumptions based on the terrestrial chemofossil record to another planet. Mars is the strongest candidate for a second planetary biosphere in the solar system. If an ancient biosphere did exist on Mars, returned samples might be expected to yield data that challenge many assumptions about what constitutes an isotopic biosignature. Mars appears to be different from the Earth. The isotopic values for the various reservoirs of carbon, nitrogen and sulfur on Mars have

  3. Isotopic ratios of H, C, N, O, and S in comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy)

    NASA Astrophysics Data System (ADS)

    Biver, N.; Moreno, R.; Bockelée-Morvan, D.; Sandqvist, Aa.; Colom, P.; Crovisier, J.; Lis, D. C.; Boissier, J.; Debout, V.; Paubert, G.; Milam, S.; Hjalmarson, A.; Lundin, S.; Karlsson, T.; Battelino, M.; Frisk, U.; Murtagh, D.; Odin Team

    2016-05-01

    The apparition of bright comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy) in March-April 2013 and January 2015, combined with the improved observational capabilities of submillimeter facilities, offered an opportunity to carry out sensitive compositional and isotopic studies of the volatiles in their coma. We observed comet Lovejoy with the IRAM 30 m telescope between 13 and 26 January 2015, and with the Odin submillimeter space observatory on 29 January-3 February 2015. We detected 22 molecules and several isotopologues. The H216O and H218O production rates measured with Odin follow a periodic pattern with a period of 0.94 days and an amplitude of ~25%. The inferred isotope ratios in comet Lovejoy are 16O/18O = 499 ± 24 and D/H = 1.4 ± 0.4 × 10-4 in water, 32S/34S = 24.7 ± 3.5 in CS, all compatible with terrestrial values. The ratio 12C/13C = 109 ± 14 in HCN is marginally higher than terrestrial and 14N/15N = 145 ± 12 in HCN is half the Earth ratio. Several upper limits for D/H or 12C/13C in other molecules are reported. From our observation of HDO in comet C/2014 Q2 (Lovejoy), we report the first D/H ratio in an Oort Cloud comet that is not larger than the terrestrial value. On the other hand, the observation of the same HDO line in the other Oort-cloud comet, C/2012 F6 (Lemmon), suggests a D/H value four times higher. Given the previous measurements of D/H in cometary water, this illustrates that a diversity in the D/H ratio and in the chemical composition, is present even within the same dynamical group of comets, suggesting that current dynamical groups contain comets formed at very different places or times in the early solar system. Based on observations carried out with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).Odin is a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the National Technology Agency of Finland (Tekes) and the

  4. Formation of Saturn and Jupiter and their Atmospheres

    NASA Astrophysics Data System (ADS)

    Atreya, S. K.; Lunine, J. I.; Simon-Miller, A. A.; Atkinson, D. H.; Brinckerhoff, W. B.; Coustenis, A.; Mahaffy, P. R.; Spilker, T. R.; Colaprete, A.; Reh, K.

    2012-04-01

    disequilibrium in the upper atmosphere. If Saturn's O/H is subsolar, a measurement of water even at shallow depths could allow its determination. CO could also provide a handle on O/H, but requires a knowledge of vertical mixing in Saturn's interior. The measurement of water and phosphine, respectively by the MWR and the Jovian InfraRed Auroral Mapper (JIRAM) on Juno, together with prior data on CO at Jupiter will provide a useful guide for determining convective mixing in Saturn as well. As in the case of Jupiter, an entry probe is essential for determining the bulk composition in Saturn's atmosphere, especially the elemental abundances of He, Ne, Ar, Kr, Xe, O, N and S and the critical isotopes, D/H, 3He/4He, 18O/16O, 13C/12C, 15N/14N, 34S/32S and the isotopes of the heavy noble gases. This would enable the type of comparative study of Saturn and Jupiter that is crucial to unraveling the mystery of the formation and evolution of the solar system and, by extension, extrasolar systems. [www.umich.edu/~atreya to download pdf's of related publications

  5. Biogeochemical fingerprints of life: earlier analogies with polar ecosystems suggest feasible instrumentation for probing the Galilean moons

    NASA Astrophysics Data System (ADS)

    Chela-Flores, J.; Cicuttin, A.; Crespo, M. L.; Tuniz, C.

    2015-07-01

    1960s) that the distribution range of 32S/34S in analysed extra-terrestrial material appears to be narrower than the isotopic ratio of H, C or N and may be the most reliable for estimating biological effects. In addition, we discuss the necessary instruments that can test our biogenic hypothesis. First of all we hasten to clarify that the last-generation miniaturized mass spectrometer we discuss in the present paper are capable of reaching the required accuracy of ‰ for the all-important measurements with JGO of the thin atmospheres of the icy satellites. To implement the measurements, we single out miniature laser ablation time-of-flight mass spectrometers that are ideal for the forthcoming JUICE probing of the exoatmospheres, ionospheres and, indirectly, surficial low-albedo regions. Ganymede's surface, besides having ancient dark terrains covering about one-third of the total surface, has bright terrains of more recent origin, possibly due to some internal processes, not excluding biological ones. The geochemical test could identify bioindicators on Europa and exclude them on its large neighbour by probing relatively recent bright terrains on Ganymede's Polar Regions.

  6. Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets

    PubMed Central

    Antonelli, Michael A.; Kim, Sang-Tae; Peters, Marc; Labidi, Jabrane; Cartigny, Pierre; Walker, Richard J.; Lyons, James R.; Hoek, Joost; Farquhar, James

    2014-01-01

    Achondrite meteorites have anomalous enrichments in 33S, relative to chondrites, which have been attributed to photochemistry in the solar nebula. However, the putative photochemical reactions remain elusive, and predicted accompanying 33S depletions have not previously been found, which could indicate an erroneous assumption regarding the origins of the 33S anomalies, or of the bulk solar system S-isotope composition. Here, we report well-resolved anomalous 33S depletions in IIIF iron meteorites (<−0.02 per mil), and 33S enrichments in other magmatic iron meteorite groups. The 33S depletions support the idea that differentiated planetesimals inherited sulfur that was photochemically derived from gases in the early inner solar system (<∼2 AU), and that bulk inner solar system S-isotope composition was chondritic (consistent with IAB iron meteorites, Earth, Moon, and Mars). The range of mass-independent sulfur isotope compositions may reflect spatial or temporal changes influenced by photochemical processes. A tentative correlation between S isotopes and Hf-W core segregation ages suggests that the two systems may be influenced by common factors, such as nebular location and volatile content. PMID:25453079

  7. Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets.

    PubMed

    Antonelli, Michael A; Kim, Sang-Tae; Peters, Marc; Labidi, Jabrane; Cartigny, Pierre; Walker, Richard J; Lyons, James R; Hoek, Joost; Farquhar, James

    2014-12-16

    Achondrite meteorites have anomalous enrichments in (33)S, relative to chondrites, which have been attributed to photochemistry in the solar nebula. However, the putative photochemical reactions remain elusive, and predicted accompanying (33)S depletions have not previously been found, which could indicate an erroneous assumption regarding the origins of the (33)S anomalies, or of the bulk solar system S-isotope composition. Here, we report well-resolved anomalous (33)S depletions in IIIF iron meteorites (<-0.02 per mil), and (33)S enrichments in other magmatic iron meteorite groups. The (33)S depletions support the idea that differentiated planetesimals inherited sulfur that was photochemically derived from gases in the early inner solar system (<∼2 AU), and that bulk inner solar system S-isotope composition was chondritic (consistent with IAB iron meteorites, Earth, Moon, and Mars). The range of mass-independent sulfur isotope compositions may reflect spatial or temporal changes influenced by photochemical processes. A tentative correlation between S isotopes and Hf-W core segregation ages suggests that the two systems may be influenced by common factors, such as nebular location and volatile content. PMID:25453079

  8. Sulfur isotopes as indicators of amended bacterial sulfate reduction processes influencing field scale uranium bioremediation.

    PubMed

    Druhan, Jennifer L; Conrad, Mark E; Williams, Kenneth H; N'Guessan, Lucie; Long, Philip E; Hubbard, Susan S

    2008-11-01

    Aqueous uranium (U(VI)) concentrations in a contaminated aquifer in Rifle Colorado have been successfully lowered through electron donor amended bioreduction. Samples collected during the acetate amendment experiment were analyzed for aqueous concentrations of Fe(ll), sulfate, sulfide, acetate, U(VI), and delta(34)S of sulfate and sulfide to explore the utility of sulfur isotopes as indicators of in situ acetate amended sulfate and uranium bioreduction processes. Enrichment of up to 7% per hundred in delta(34)S of sulfate in down-gradient monitoring wells indicates a transition to elevated bacterial sulfate reduction. A depletion in Fe(II), sulfate, and sulfide concentrations atthe height of sulfate reduction, along with an increase in the delta(34)S of sulfide to levels approaching the delta(34)S values of sulfate, indicates sulfate limited conditions concurrent with a rebound in U(VI) concentrations. Upon cessation of acetate amendment, sulfate and sulfide concentrations increased, while delta(34)S values of sulfide returned to less than -20% per hundred and sulfate delta(34)S decreased to near-background values, indicating lower levels of sulfate reduction accompanied by a corresponding drop in U(VI). Results indicate a transition between electron donor and sulfate-limited conditions at the height of sulfate reduction and suggest stability of biogenic FeS precipitates following the end of acetate amendment. PMID:19031870

  9. Characteristics of a strong promoter from figwort mosaic virus: comparison with the analogous 35S promoter from cauliflower mosaic virus and the regulated mannopine synthase promoter.

    PubMed

    Sanger, M; Daubert, S; Goodman, R M

    1990-03-01

    A segment of DNA from the genome of figwort mosaic virus (FMV) strain M3 possesses promoter activity when tested in electroporated protoplasts from, and transgenic plants of, Nicotiana tabacum cv. Xanthi nc. The 1.1 kb DNA segment, designated the '34S' promoter, is derived from a position on the FMV genome comparable to the position on the cauliflower mosaic virus (CaMV) genome containing the 35S promoter. The 34S and 35S promoters show approximately 63% nucleotide homology in the TATA, CCACT, and -18 to +1 domains, but in sequences further upstream the homology drops below 50%. Promoter activities were estimated using beta-glucuronidase and neomycin phosphotransferase II reporter gene systems. The activity of the 34S promoter segment approximates that of the 35S promoter in both protoplast transient expression assays and in stably transformed tobacco plants. Truncation of 5' sequences from the 34S promoter indicates that promoter strength depends upon DNA sequences located several hundred nucleotides upstream from the TATA box. In leaf tissue the 34S promoter is 20-fold more active than the mannopine synthase (MAS) promoter from Agrobacterium tumefaciens T-DNA. The 34S promoter lacks the root-specific and wound-stimulated expression of the MAS promoter, showing relatively uniform root, stem, leaf, and floral activities. PMID:2102823

  10. Evidence for life in the isotopic analysis of surface sulphates in the Haughton impact structure, and potential application on Mars

    NASA Astrophysics Data System (ADS)

    Parnell, John; Boyce, Adrian J.; Osinski, Gordon R.; Izawa, Matthew R. M.; Banerjee, Neil; Flemming, Roberta; Lee, Pascal

    2012-04-01

    The analysis of sulphur isotopic compositions in three sets of surface sulphate samples from the soil zone in the Haughton impact structure shows that they are distinct. They include surface gypsum crusts remobilized from the pre-impact gypsum bedrock (mean δ34S +31‰), efflorescent copiapite and fibroferrite associated with hydrothermal marcasite (mean δ34S -37‰), and gypsum-iron oxide crusts representing weathering of pyritic crater-fill sediments (mean δ34S +7‰). Their different compositions reflect different histories of sulphur cycling. Two of the three sulphates have isotopically light (low δ34S) compositions compared with the gypsum bedrock (mean δ34S +31‰), reflecting derivation by weathering of sulphides (three sets of pyrite/marcasite samples with mean δ34S of -41, -20 and -8‰), which had in turn been precipitated by microbial sulphate reduction. Thus, even in the absence of the parent sulphides due to surface oxidation, evidence of life would be preserved. This indicates that on Mars, where surface oxidation may rule out sampling of sulphides during robotic exploration, but where sulphates are widespread, sulphur isotope analysis is a valuable tool that could be sensitive to any near-surface microbial activity. Other causes of sulphur isotopic fractionation on the surface of Mars are feasible, but any anomalous fractionation would indicate the desirability of further analysis.

  11. Sulfur Isotopes as Indicators of Amended Bacterial Sulfate Reduction Processes Influencing Field Scale Uranium Bioremediation

    SciTech Connect

    Druhan, Jennifer L.; Conrad, Mark E.; Williams, Kenneth H.; N'Guessan, A. Lucie; Long, Philip E.; Hubbard, Susan S.

    2008-11-01

    Aqueous uranium (U(VI)) concentrations in a contaminated aquifer in Rifle Colorado have been successfully lowered through electron donor amended bioreduction. Samples collected during the acetate amendment experiment were analyzed for aqueous concentrations of Fe(II), sulfate, sulfide, acetate, U(VI), and δ34S of sulfate and sulfide to explore the utility of sulfur isotopes as indicators of in situ acetate amended sulfate and uranium bioreduction processes. Enrichment of up to 7‰ in δ34S of sulfate in down-gradient monitoring wells indicates a transition to elevated bacterial sulfate reduction. A depletion in Fe(II), sulfate, and sulfide concentrations at the height of sulfate reduction, along with an increase in the δ34S of sulfide to levels approaching the d34S values of sulfate, indicates sulfate limited conditions concurrent with a rebound in U(VI) concentrations. Upon cessation of acetate amendment, sulfate and sulfide concentrations increased, while δ34S values of sulfide returned to less than -20‰ and sulfate δ34S decreased to near-background values, indicating lower levels of sulfate reduction accompanied by a corresponding drop in U(VI). Results indicate a transition between electron donor and sulfate-limited conditions at the height of sulfate reduction and suggest stability of biogenic FeS precipitates following the end of acetate amendment.

  12. Effects of strain on phonon interactions and phase nucleation in several semiconductor and nano particle systems

    NASA Astrophysics Data System (ADS)

    Tallman, Robert E.

    Raman scattering is utilized to explore the effects of applied pressure and strain on anharmonic phonon interactions and nucleation of structural transitions in several bulk and nanoparticle semiconductor systems. The systems investigated are bulk ZnS and ZnSe in several isotopic compositions, InP/CdS core/shell nanoparticles exhibiting confined and surface optical Raman modes, and amorphous selenium films undergoing photo-induced crystallization. The anharmonic decay of long-wavelength optical modes into two-phonon acoustic combinations modes is studied in 64Zn32S, 64Zn34S, natZnatS bulk crystals by measuring the TO(Gamma) Raman line-shape as a function of applied hydrostatic pressure. The experiments are carried out at room temperature and 16K for pressures up to 150 kbars using diamond-anvil cells. The most striking effects occur in 68Zn32S where the TO(Gamma) peak narrows by a factor of 10 and increases in intensity at pressures for which the TO(Gamma) frequency has been tuned into a gap in the two-phonon density of states (DOS). In all the isotopic compositions, the observed phonon decay processes can be adequately explained by a second order perturbation treatment of the anharmonic coupling between TO(Gamma) and TA + LA combinations at various critical points, combined with an adiabatic bond-charge model for the phonon DOS and the known mode Gruneisen parameters. Bulk ZnSe crystals exhibit very different behavior. Here we find that anharmonic decay alone can not explain the excessive (˜ 60 cm-1 ) broadening in the TO(Gamma) Raman peak observed as the pressure approaches to within 50kbar of the ZB -> B1 phase transition (at P ˜ 137 kbar). Rather the broadening appears to arise from antecedent nucleation of structural changes within nanoscopic domains, with the mechanism for line-shape changes being mode mixing via localization and disorder instead of anharmonicity. To sort out these contributions, pressure experiments on natural ZnSe and on isotopically pure

  13. Compound-specific sulfur isotope analysis of thiadiamondoids of oils from the Smackover Formation, USA

    USGS Publications Warehouse

    Zvi Gvirtzman; Ward Said-Ahmad; Ellis, Geoffrey S.; Ronald J. Hill; J. Michael Moldowan; Zhibin Wei; Alon Amrani

    2015-01-01

    Thiadiamondoids (TDs) are diamond-like compounds with a sulfide bond located within the cage structure. These compounds were suggested as a molecular proxy for the occurrence and extent of thermochemical sulfate reduction (TSR). Compound-specific sulfur-isotope analysis of TDs may create a multi-parameter system, based on molecular and δ34S values that may be sensitive over a wider range of TSR and thermal maturation stages. In this study, we analyzed a suite of 12 Upper Jurassic oil and condensate samples generated from source rocks in the Smackover Formation to perform a systematic study of the sulfur isotope distribution in thiadiamondoids (one and two cages). For comparison we measured the δ34S composition of benzothiophenes (BTs) and dibenzothiophenes (DBTs). We also conducted pyrolysis experiments with petroleum and model compounds to have an insight into the formation mechanisms of TDs. The δ34S of the TDs varied significantly (ca 30‰) between the different oils depending on the degree of TSR alteration. The results showed that within the same oil, the one-cage TDs were relatively uniform, with 34S enriched values similar to those of the coexisting BTs. The two-cage TDs had more variable δ34S values that range from the δ34S values of BTs to those of the DBTs, but with general 34S depletion relative to one cage TDs. Hydrous pyrolysis experiments (360 °C, 40 h) with either CaSO4 or elemental S (equivalent S molar concentrations) and adamantane as a model compound demonstrate the formation of one cage TDs in relatively low yields (<0.2%). Higher concentrations of TDs were observed in the elemental sulfur experiments, most likely because of the higher rates of reaction with adamantane under these experimental conditions. These results show that the formation of TDs is not exclusive to TSR reactions, and that they can also form by reaction with reduced S species apart from sulfate reduction, though at low yields. Oxygenated compounds, most notably 2

  14. Compound-specific sulfur isotope analysis of thiadiamondoids of oils from the Smackover Formation, USA

    NASA Astrophysics Data System (ADS)

    Gvirtzman, Zvi; Said-Ahmad, Ward; Ellis, Geoffrey S.; Hill, Ronald J.; Moldowan, J. Michael; Wei, Zhibin; Amrani, Alon

    2015-10-01

    Thiadiamondoids (TDs) are diamond-like compounds with a sulfide bond located within the cage structure. These compounds were suggested as a molecular proxy for the occurrence and extent of thermochemical sulfate reduction (TSR). Compound-specific sulfur-isotope analysis of TDs may create a multi-parameter system, based on molecular and δ34S values that may be sensitive over a wider range of TSR and thermal maturation stages. In this study, we analyzed a suite of 12 Upper Jurassic oil and condensate samples generated from source rocks in the Smackover Formation to perform a systematic study of the sulfur isotope distribution in thiadiamondoids (one and two cages). For comparison we measured the δ34S composition of benzothiophenes (BTs) and dibenzothiophenes (DBTs). We also conducted pyrolysis experiments with petroleum and model compounds to have an insight into the formation mechanisms of TDs. The δ34S of the TDs varied significantly (ca 30‰) between the different oils depending on the degree of TSR alteration. The results showed that within the same oil, the one-cage TDs were relatively uniform, with 34S enriched values similar to those of the coexisting BTs. The two-cage TDs had more variable δ34S values that range from the δ34S values of BTs to those of the DBTs, but with general 34S depletion relative to one cage TDs. Hydrous pyrolysis experiments (360 °C, 40 h) with either CaSO4 or elemental S (equivalent S molar concentrations) and adamantane as a model compound demonstrate the formation of one cage TDs in relatively low yields (<0.2%). Higher concentrations of TDs were observed in the elemental sulfur experiments, most likely because of the higher rates of reaction with adamantane under these experimental conditions. These results show that the formation of TDs is not exclusive to TSR reactions, and that they can also form by reaction with reduced S species apart from sulfate reduction, though at low yields. Oxygenated compounds, most notably 2

  15. Sulfur isotope dynamics in two central european watersheds affected by high atmospheric deposition of SO x

    NASA Astrophysics Data System (ADS)

    Novák, Martin; Kirchner, James W.; Groscheová, Hana; Havel, Miroslav; Černý, Jiří; Krejčí, Radovan; Buzek, František

    2000-02-01

    Sulfur fluxes and δ34S values were determined in two acidified small watersheds located near the Czech-German border, Central Europe. Sulfur of sulfate aerosol in the broader region (mean δ 34S of 7.5‰ CDT) was isotopically heavier than sulfur of airborne SO 2 (mean δ 34S of 4.7‰). The annual atmospheric S deposition to the Jezeřı´ watershed decreased markedly in 1993, 1994, and 1995 (40, 33, and 29 kg/ ha · yr), reflecting reductions in industrial S emissions. Sulfur export from Jezeří via surface discharge was twice atmospheric inputs, and increased from 52 to 58 to 85 kg/ha · yr over the same three-year period. The δ 34S value of Jezeřı´ streamflow was 4.5 ± 0.3‰, intermediate between the average atmospheric deposition (5.4 ± 0.2‰) and soil S (4.0 ± 0.5‰), suggesting that the excess sulfate in runoff comes from release of S from the soil. Bedrock is not a plausible source of the excess S, because its S concentration is very low (<0.003 wt.%) and because its δ 34S value is too high (5.8‰) to be consistent with the δ 34S of runoff. A sulfur isotope mixing model indicated that release of soil S accounted for 64 ± 33% of sulfate S in Jezeřı´ discharge. Approximately 30% of total sulfate S in the discharge were organically cycled. At Načetı´n, the same sequence of δ34S IN > δ34S OUT > δ34S SOIL was observed. The seasonality found in atmospheric input (higher δ 34S in summer, lower δ 34S in winter) was preserved in shallow (<10 cm) soil water, but not in deeper soil water. δ 34S values of deeper (>10 cm) soil water (4.8 ± 0.2‰) were intermediate between those of atmospheric input (5.9 ± 0.3‰) and Nac̆etín soils (2.4 ± 0.1‰), again suggesting that remobilization of soil S accounts for a significant fraction (roughly 40 ± 10%) of the S in soil water at Načetı´n. The inventories of soil S at both of these sites are legacies of more intense atmospheric pollution during previous decades, and are large enough (740

  16. Involvement of magmatic fluids at the Laloki and Federal Flag massive sulfide Cu-Zn-Au-Ag deposits, Astrolabe mineral district, Papua New Guinea: sulfur isotope evidence

    NASA Astrophysics Data System (ADS)

    Noku, Shadrach K.; Espi, Joseph O.; Matsueda, Hiroharu

    2015-01-01

    We present the first sulfur (S) isotope data of sulfides, sulfates, pyrite in host mudstone, and bulk sulfur of gabbroic rocks from the Laloki and Federal Flag massive Cu-Zn-Au-Ag deposits in the Astrolabe mineral district, Papua New Guinea. Early-stage pyrite-marcasite, chalcopyrite, and sphalerite from Laloki display wide range of δ34S values from -4.5 to +7.0 ‰ ( n = 16). Late-stage pyrite, chalcopyrite, and sphalerite have restricted δ34S values of -1.9 to +4.7 ‰ ( n = 16). The mineralizing stage these correspond to had moderately saline (5.9-8.4 NaCl eq. wt%) mineralizing fluids of possible magmatic origin. A single analysis of late-stage barite has a value of δ34S +17.9 ‰, which is likely similar to coexisting seawater sulfate. Pyrite from the foot-wall mudstone at Laloki has very light δ34S values of -36.1 to -33.8 ‰ ( n = 2), which suggest an organic source for S. Pyrite-marcasite and chalcopyrite from Federal Flag show δ34S values of -2.4 to -1.9 ‰ ( n = 2), consistent with a magmatic origin, either leached from intrusive magmatic rocks or derived from magmatic-hydrothermal fluids. The very narrow range and near-zero δ34S values (-1.0 to +0.6 ‰) of bulk gabbroic samples is consistent with mantle-derived magmatic S. Sulfur isotope characteristics of sulfides and sulfates are, however, very similar to base metal sulfide accumulations associated with modern volcanic arcs and sedimented mid-ocean ridges. The most reasonable interpretation is that the range of the sulfide and sulfate δ34S values from both Laloki and Federal Flag massive sulfide deposits is indicative of the complex interaction of magmatic fluids, seawater, gabbroic rocks, and mudstone.

  17. Sulfur isotope fractionation during bacterial reduction and disproportionation of thiosulfate and sulfite

    SciTech Connect

    Habicht, K.S.; Canfield, D.E.; Rethmeier, J.

    1998-08-01

    In bacterial cultures the authors measured sulfur isotope fractionation during transformations of thiosulfate and sulfite, pathways which may be of considerable importance in the cycling of sulfur in marine sediments and euxinic waters. They documented isotope fractionations during the reduction and disproportionation of thiosulfate and sulfite by bacterial enrichments and pure bacterial cultures from marine and freshwater environments. They also measured the isotope fractionation associated with the anoxygenic phototrophic oxidation of H{sub 2}S to thiosulfate by cyanobacteria. Except for sulfite reduction, isotope fractionations for these processes have not been previously reported. During the dissimilatory reduction of sulfite, H{sub 2}S was depleted in {sup 34}S by 6%, and during the reduction of thiosulfate to H{sub 2}S, depletions were between 7% and 11%. The largest observed isotope fractionation was associated with the bacterial disproportionation of sulfite which caused a {sup 34}S depletion in H{sub 2}S of 20--37% and a {sup 34}S enrichment in sulfate of 7--12%. During the bacterial disproportionation of thiosulfate, isotope fractionations between the outer sulfane sulfur and H{sub 2}S and between the inner sulfonate sulfur and sulfate were <4%. The authors observed isotope exchange between the two sulfur atoms of thiosulfate leading to a depletion of {sup 34}S in H{sub 2}S by up to 12% with a comparable enrichment of {sup 34}S in sulfate. No isotope fractionation was associated with the anoxygenic phototrophic oxidation of H{sub 2}S to thiosulfate. The depletion of {sup 34}S into H{sub 2}S during the bacterial reduction and disproportionation of thiosulfate and sulfite may, in addition to sulfate reduction and the bacterial disproportionation of elemental sulfur, contribute to the generation of {sup 34}S-depleted sedimentary sulfides.

  18. Origin of sulfide and phosphate deposits in Upper Proterozoic carbonate strata, Irece basin, Bahia, Brazil

    SciTech Connect

    Kyle, J.R. ); Misi, A. )

    1991-03-01

    Carbonate strata of the Una Group represent late Proterozoic platform sedimentation in the Irece basin of north-central Brazil. Stratabound sulfide- and phosphate-rich units occur within a 50-m thick tidal flat sequence of dolomitic limestone and cherty dolomite. Three types of primary phosphate concentrations are present: columnar stromatolitic, laminar stromatolitic, and intraclastic. Resedimented phosphate clasts and phosphatic units interbedded with non phosphatic dolomites suggest early diagenetic replacement of algal carbonate units. Local stratabound Zn-Pb-Ag sulfide concentrations at the Tres Irmas prospect occur within silty dolomite with shallow water sedimentary structures and local disturbed laminae, synsedimentary faults, and breccias. Sulfide minerals include pyrite, sphalerite, galena, marcasite, jordanite, tetrahedrite, and covellite. Pyrite crystal aggregates commonly show bladed forms. Nodular aggregates of length-slow quartz are locally associated with sulfides. Sulfur isotope analyses indicate relatively uniform heavy {delta}{sup 34}S values. Barite shows a {delta}{sup 34}S range from +25.2 to +29.6{per thousand}, CDT. Pyrite and sphalerite representative of a variety of textural types have a {delta}{sup 34}S range of +20.2 to +22.6{per thousand}. Late Proterozoic evaporite sulfates show a wide range of {delta}{sup 34} S values from about +10 to +28{per thousand}. Thus, the {delta}{sup 34}S values for Irece barite could reflect original seawater sulfate values. However, the relatively heavy {delta}{sup 34}S values of the associated sulfides suggests that the original seawater sulfate was modified by bacterial sulfate reduction processes in shallow sea floor sediments. Textural and {delta}{sup 34}S evidence suggests that a later stage of metallic mineralization scavenged sulfur from preexisting sulfides or from direct reduction of evaporitic sulfate minerals.

  19. Sulfur isotope systematics of basaltic lavas from Indonesia: implications for the sulfur cycle in subduction zones

    NASA Astrophysics Data System (ADS)

    de Hoog, J. C. M.; Taylor, B. E.; van Bergen, M. J.

    2001-07-01

    We report sulfur isotope compositions of basaltic and basaltic andesite lavas from selected volcanoes in the Indonesian arc system covering the spectrum from low-K tholeiitic to high-K calc-alkaline compositions. The results of 25 samples from seven volcanoes, which are associated with different subduction regimes, show a range in δ34S values of +2.0-+7.8‰ (VCDT) with an average of +4.7±1.4‰ (1σ). Averages and within-suite variations of two larger sets of samples from Batur and Soputan volcanoes (+4.2±1.3‰ with n=9 and +5.7±1.4‰ with n=7, respectively) are comparable to those of the entire sample set. Sulfur concentrations are low (mostly between 2 and 74 ppm, average=19 ppm) and do not show correlations with sulfur isotope composition and whole-rock chemistry, or systematic changes with time in any of the lava suites. From model calculations we infer that basaltic magmas will undergo sulfur isotope fractionation during degassing, most commonly towards lower δ34S values, but that the extent is limited at P-T conditions and oxidation states of interest. Hence, δ34S signatures of basaltic lavas will generally be within a few permil from primary magmatic values, even in cases of extensive sulfur loss. Consequently, magmas in the Indonesian arc system originate from mantle sources that are enriched in 34S relative to MORB and OIB sources and are likely to have δ34S values of about +5-+7‰. The enrichment in 34S is considered to reflect addition of slab-derived material, presumably from sediments rather than altered oceanic crust, with fluids being the most likely transport medium. Absence of correlation between δ34S values of Indonesian basalts and chemical proxies for source components or processes at the slab-wedge interface suggests that sulfur isotopes are relatively insensitive to variations in subduction setting and dynamics. This is supported by the modest range in δ34S of the Indonesian volcanoes studied despite significant variations in the

  20. SPINK1 Is a Susceptibility Gene for Fibrocalculous Pancreatic Diabetes in Subjects from the Indian Subcontinent

    PubMed Central

    Hassan, Zahid; Mohan, Viswananthan; Ali, Liaquat; Allotey, Rebecca; Barakat, Khalid; Faruque, M. Omar; Deepa, Raj; McDermott, Michael F.; Jackson, Alan E.; Cassell, Paul; Curtis, David; Gelding, Susan V.; Vijayaravaghan, Shanti; Gyr, Niklaus; Whitcomb, David C.; Khan, A. K. Azad; Hitman, Graham A.

    2002-01-01

    Fibrocalculous pancreatic diabetes (FCPD) is a secondary cause of diabetes due to chronic pancreatitis. Since the N34S variant of the SPINK1 trypsin inhibitor gene has been found to partially account for genetic susceptibility to chronic pancreatitis, we used a family-based and case-control approach in two separate ethnic groups from the Indian subcontinent, to determine whether N34S was associated with susceptibility to FCPD. Clear excess transmission of SPINK1 N34S to the probands with FCPD in 69 Bangladeshi families was observed (P<.0001; 20 transmissions and 2 nontransmissions). In the total study group (Bangladeshi and southern Indian) the N34S variant was present in 33% of 180 subjects with FCPD, 4.4% of 861 nondiabetic subjects (odds ratio 10.8; P<.0001 compared with FCPD), 3.7% of 219 subjects with type 2 diabetes, and 10.6% of 354 subjects with early-onset diabetes (aged <30 years) (P=.02 compared with the ethnically matched control group). These results suggest that the N34S variant of SPINK1 is a susceptibility gene for FCPD in the Indian subcontinent, although, by itself, it is not sufficient to cause disease. PMID:12187509

  1. Sulfur redox reactions: Hydrocarbons, native sulfur, Mississippi Valley-type deposits, and sulfuric acid karst in the Delaware Basin, New Mexico and Texas

    SciTech Connect

    Hill, C.A.

    1995-02-01

    Hydrocarbons, native sulfur, Mississippi Valley-type (MVT) deposits, and sulfuric acid karst in the Delaware Basin, southeastern New Mexico, and west Texas, USA, are all genetically related through a series of sulfur redox reactions. The relationship began with hydrocarbons in the basin that reacted with sulfate ions from evaporite rock to produce isotopically light ({delta}{sup 34}S = -22 to -12) H{sub 2}S and bioepigenetic limestone (castiles). This light H{sub 2}S was then oxidized at the redox interface to produce economic native sulfur deposits ({delta}{sup 34}S = -15 to +9) in the castiles, paleokarst, and along graben-boundary faults. This isotopically light H{sub 2}S also migrated from the basin into its margins to accumulate in structural (anticlinal) and stratigraphic (Yates siltstone) traps, where it formed MVT deposits within the zone of reduction ({delta}{sup 34}S = -15 to +7). Later in time, in the zone of oxidation, this H{sub 2}S reacted with oxygenated water to produce sulfuric acid, which dissolved the caves (e.g., Carlsbad Cavern and Lechuguilla Cave, Guadalupe Mountains). Massive gypsum blocks on the floors of the caves ({delta}{sup 34}S = -25 to +4) were formed as a result of this reaction. The H{sub 2}S also produced isotopically light cave sulfur ({delta}{sup 34}S = -24 to -15), which is now slowly oxidizing to gypsum in the presence of vadose drip water. 16 refs., 10 figs.

  2. Indicating atmospheric sulfur by means of S-isotope in leaves of the plane, osmanthus and camphor trees.

    PubMed

    Xiao, Hua-Yun; Wang, Yan-Li; Tang, Cong-Guo; Liu, Cong-Qiang

    2012-03-01

    Foliar δ(34)S values of three soil-growing plant species (Platanus Orientalis L., Osmanthus fragrans L. and Cinnamomum camphora) have been analyzed to indicate atmospheric sulfur. The foliar δ(34)S values of the three plant species averaged -3.11±1.94‰, similar to those of both soil sulfur (-3.73±1.04‰) and rainwater sulfate (-3.07±2.74‰). This may indicate that little isotopic fractionation had taken place in the process of sulfur uptake by root or leaves. The δ(34)S values changed little in the transition from mature leaves to old/senescing leaves for both the plane tree and the osmanthus tree, suggestive of little isotope effect during sulfur redistribution in plant tissues. Significantly linear correlation between δ(34)S values of leaves and rainwater sulfate for the plane and osmanthus trees allowed the tracing of temporal variations of atmospheric sulfur by means of foliar sulfur isotope, while foliage δ(34)S values of the camphor is not an effective indicator of atmospheric sulfur. PMID:22243850

  3. Stable isotopic evidence for anaerobic maintained sulphate discharge in a polythermal glacier

    NASA Astrophysics Data System (ADS)

    Ansari, A. H.

    2016-03-01

    To understand the sources and sinks of sulphate and associated biogeochemical processes in a High Arctic environment, late winter snowpacks, the summer melt-waters and rock samples were collected and analysed for major ions and stable isotope tracers (δ18O, δ34S). The SO42bar/Clbar ratio reveal that more than 87% of sulphate (frequently > 95%) of total sulphate carried by the subglacial runoff and proglacial streams was derived from non-snowpack sources. The proximity of non-snowpack sulphate δ34S (∼8-19‰) to the δ34S of the major rocks in the vicinity (∼-6 to +18‰) suggest that the non-snowpack sulphate was principally derived from rock weathering. Furthermore, Ca2++Mg2+/SO42ˉ molar shows that sulphate acquisition in the meltwaters was controlled by two major processes: 1) coupled-sulphide carbonate weathering (molar ratio ∼ 2) and, 2) re-dissolution of secondary salts (molar ratio ∼ 1). The δ34S-SO4 = +19.4‰ > δ34S-S of rock, accompanied by increased sulphate concentration also indicates an input from re-dissolution of secondary salts. Overall, δ18O composition of these non-snowpack sulphate (-11.9 to -2.2‰) mostly stayed below the threshold δ18O value (-6.7 to -3.3‰) for minimum O2 condition, suggesting that certain proportion of sulphate was regularly supplied from anaerobic sulphide oxidation.

  4. The multiple sulfur isotopic composition of iron meteorites: Implications for nebular evolution

    NASA Astrophysics Data System (ADS)

    Antonelli, Michael Ariel

    2013-12-01

    Multiple sulfur isotopic measurements of troilite from 61 different iron meteorites were undertaken in order to test for sulfur isotopic homogeneity within (and between) 8 different iron meteorite groups. It was found that different members within a given group of iron meteorites have homogeneous Delta 33S compositions, but that these Delta33S compositions differ between groups. This thesis shows that iron meteorites from the groups IC, IIAB, IIIAB, IIIF, and IVA have small yet resolvable enrichments or depletions in Delta33S relative to Canyon Diablo Troilite (CDT) and troilite from other non-magmatic (IAB and IIE) iron meteorites. The observed anomalous sulfur isotopic compositions in magmatic iron meteorites are most consistent with Lyman-alpha photolysis of H2S, pointing towards inheritance of an unexpected photolytically-derived sulfur component in magmatic iron meteorite groups which is absent in non-magmatic iron meteorites, chondrites, and the Earth-Moon System.

  5. Protein unfolding as a switch from self-recognition to high-affinity client binding.

    PubMed

    Groitl, Bastian; Horowitz, Scott; Makepeace, Karl A T; Petrotchenko, Evgeniy V; Borchers, Christoph H; Reichmann, Dana; Bardwell, James C A; Jakob, Ursula

    2016-01-01

    Stress-specific activation of the chaperone Hsp33 requires the unfolding of a central linker region. This activation mechanism suggests an intriguing functional relationship between the chaperone's own partial unfolding and its ability to bind other partially folded client proteins. However, identifying where Hsp33 binds its clients has remained a major gap in our understanding of Hsp33's working mechanism. By using site-specific Fluorine-19 nuclear magnetic resonance experiments guided by in vivo crosslinking studies, we now reveal that the partial unfolding of Hsp33's linker region facilitates client binding to an amphipathic docking surface on Hsp33. Furthermore, our results provide experimental evidence for the direct involvement of conditionally disordered regions in unfolded protein binding. The observed structural similarities between Hsp33's own metastable linker region and client proteins present a possible model for how Hsp33 uses protein unfolding as a switch from self-recognition to high-affinity client binding. PMID:26787517

  6. Correlations Between Surficial Sulfur and a REE Crustal Assimilation Signature in Martian Shergottites

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Franz, H. B.

    2015-01-01

    Compared to terrestrial basalts, the Martian shergottite meteorites have an extraordinary range of Sr and Nd isotopic signatures. In addition, the S isotopic compositions of many shergottites show evidence of interaction with the Martian surface/ atmosphere through mass-independent isotopic fractionations (MIF, positive, non-zero delta(exp 33)S) that must have originated in the Martian atmosphere, yet ultimately were incorporated into igneous sulfides (AVS - acid-volatile sulfur). These positive delta(exp 33)S signatures are thought to be governed by solar UV photochemical processes. And to the extent that S is bound to Mars and not lost to space from the upper atmosphere, a positive delta(exp 33)S reservoir must be mass balanced by a complementary negative reservoir.

  7. Large sulfur isotope fractionations associated with Neoarchean microbial sulfate reduction.

    PubMed

    Zhelezinskaia, Iadviga; Kaufman, Alan J; Farquhar, James; Cliff, John

    2014-11-01

    The minor extent of sulfur isotope fractionation preserved in many Neoarchean sedimentary successions suggests that sulfate-reducing microorganisms played an insignificant role in ancient marine environments, despite evidence that these organisms evolved much earlier. We present bulk, microdrilled, and ion probe sulfur isotope data from carbonate-associated pyrite in the ~2.5-billion-year-old Batatal Formation of Brazil, revealing large mass-dependent fractionations (approaching 50 per mil) associated with microbial sulfate reduction, as well as consistently negative Δ(33)S values (~ -2 per mil) indicative of atmospheric photochemical reactions. Persistent (33)S depletion through ~60 meters of shallow marine carbonate implies long-term stability of seawater sulfate abundance and isotope composition. In contrast, a negative Δ(33)S excursion in lower Batatal strata indicates a response time of ~40,000 to 150,000 years, suggesting Neoarchean sulfate concentrations between ~1 and 10 μM. PMID:25378623

  8. Protein unfolding as a switch from self-recognition to high-affinity client binding

    PubMed Central

    Groitl, Bastian; Horowitz, Scott; Makepeace, Karl A. T.; Petrotchenko, Evgeniy V.; Borchers, Christoph H.; Reichmann, Dana; Bardwell, James C. A.; Jakob, Ursula

    2016-01-01

    Stress-specific activation of the chaperone Hsp33 requires the unfolding of a central linker region. This activation mechanism suggests an intriguing functional relationship between the chaperone's own partial unfolding and its ability to bind other partially folded client proteins. However, identifying where Hsp33 binds its clients has remained a major gap in our understanding of Hsp33's working mechanism. By using site-specific Fluorine-19 nuclear magnetic resonance experiments guided by in vivo crosslinking studies, we now reveal that the partial unfolding of Hsp33's linker region facilitates client binding to an amphipathic docking surface on Hsp33. Furthermore, our results provide experimental evidence for the direct involvement of conditionally disordered regions in unfolded protein binding. The observed structural similarities between Hsp33's own metastable linker region and client proteins present a possible model for how Hsp33 uses protein unfolding as a switch from self-recognition to high-affinity client binding. PMID:26787517

  9. Sulphur diagenesis in the sediments of the Kiel Bight, SW Baltic Sea, as reflected by multiple stable sulphur isotopes.

    PubMed

    Strauss, Harald; Bast, Rebecca; Cording, Anja; Diekrup, David; Fugmann, Artur; Garbe-Schönberg, Dieter; Lutter, Andreas; Oeser, Martin; Rabe, Katharina; Reinke, Debora; Teichert, Barbara M A; Westernströer, Ulrike

    2012-01-01

    In this work, the biogeochemistry of marine sediments from the Kiel Bight, coastal SW Baltic Sea, is studied based on the abundance and isotopic composition of organic carbon and different forms of sedimentary sulphur. Active bacterial sulphate reduction, partly under sulphate-limiting conditions, is evident from paired δ(34)S and δ(18)O values of pore water sulphate. The resulting pore water sulphide is partly precipitated as acid-volatile iron sulphide and subsequently forms sedimentary pyrite, partly serves in later diagenetic sulphurisation of organic matter, or remains dissolved in the pore water, all evident from the respective δ(34)S values. Microbial sulphate turnover is associated with an apparent isotopic fractionation between dissolved sulphate and dissolved sulphide (Δ(34)S) that varies between 46 and 66‰. PMID:22303924

  10. VizieR Online Data Catalog: Atomic data of vanadium (V I) (Wang+, 2014)

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Jiang, L. Y.; Quinet, P.; Palmeri, P.; Zhang, W.; Shang, X.; Tian, Y. S.; Dai, Z. W.

    2014-05-01

    Radiative lifetimes of 79 levels belonging to the 3d34s4p, 3d< 3d34s5p, 3d45p, and 3d34s4d configurations of V I with energy from 26604.807 to 46862.786cm-1 have been measured using time-resolved laser-induced fluorescence (TR-LIF) spectroscopy in laser-produced plasma. The lifetime values reported in this paper are in the range of 3.3-494ns, and the uncertainties of these measurements are within +/-10%. A good agreement was obtained with previous data. HFR+CPOL (Hartree-Fock with relativistic corrections method - Cowan; 1981tass.book.....C + core-polarization; Quinet et al. 1999MNRAS.307..934Q) calculations have been performed and used to combine the calculated branching fractions with the available experimental lifetimes to determine semi-empirical transition probabilities for 784 V I transitions. (1 data file).

  11. Sulfur isotopic systematics in alteration assemblages in martian meteorite Allan Hills 84001

    SciTech Connect

    Shearer, C.K.; Layne, G.D.; Papike, J.J.; Spilde, M.N.

    1996-08-01

    ALH84001 is a coarse-grained, clastic orthopyroxenite meteorite related to the SNC meteorite group (shergottites, nakhlites, Chassigny). Superimposed upon the orthopyroxene-dominant igneous mineral assemblage is a hydrothermal signature. This hydrothermal overprint consists of carbonate assemblages occurring in spheroidal aggregates and fine-grained carbonate-sulfide vug-filling. The sulfide in this assemblage has been identified as pyrite, an unusual sulfide in meteorites. Previously, Burgess et al. (1989) reported a bulk {delta} {sup 34}S for a SNC group meteorite (Shergotty) of -0.5 {+-} 1.5%. Here, we report the first martian {delta} {sup 34}S values from individual sulfide grains. Using newly developed ion microprobe techniques, we were able to determine {delta} {sup 34}S of the pyrite in ALH84001 with a 1 {alpha} precision of better than {+-}0.5%. The {delta} {sup 34}S values for the pyrite range from +4.8 to +7.8%. Within the stated uncertainties, the pyrite from ALH84001 exhibits a real variability in {delta} {sup 34}S in this alteration assemblage. In addition, these sulfides are demonstrably enriched in {sup 34}S relative to Canon Diablo troilite and sulfides from most other meteorites. This signature implies that the planetary body represented by ALH 84001 experienced processes capable of fractionating sulphur isotopes and that hydrothermal conditions changed during pyrite precipitation (T, pH, fluid composition, etc.). These new data are not consistent with the pyrite recording either biogenic activity or atmospheric fractionation of sulphur through nonthermal escape mechanisms or oxidation processes. This study also demonstrates the usefulness of ion microprobe measurements of sulphur isotopes in constraining conditions on other planetary bodies.

  12. Sulphur isotope hydrology in Skeidararsandur, Iceland: Identification of sources and implications for weathering processes

    NASA Astrophysics Data System (ADS)

    Robinson, Z. P.; Fairchild, I. J.; Spiro, B.

    2009-04-01

    The hydrochemistry of sulphur in various environments in the active ice-marginal outwash plain of Skeiðarársandur, SE Iceland shows considerable variety reflecting differences in sources and processes, and is investigated in this paper using ^34S values of dissolved sulphate and igneous sulphide minerals, ^18O-H2O, electrical conductivity and ionic concentrations in waters. Seawater-derived sulphate is a notable component only in the lower sandur (^34S-SO4 values of +6.8 o/ooVCDT). Sulphur isotope samples from the Skeiðará glacial melt river range from +3.4 to +8.8 o/oo^34S. The higher values occur during a flood event and reflect geothermal reduced sulphate contributions from the Grímsvötn caldera. Groundwater-fed 'kettle-hole lakes' formed since 1996 form important ecological niches within an otherwise relatively barren region and have the lowest ^34S-SO4values (average -0.8 o/oo ^34S) attributed to bacterially-mediated sulphide oxidation and coupled to carbonate and possibly silicate dissolution. The hydrochemistry of eastern sandur groundwater is influenced by a hydrothermal source of reduced sulphate from the Grímsvötn caldera or an area of geothermal springs routed beneath the Skeiðará river, and contrasts with the hydrochemistry of the Sulá and Gígjukvísl rivers in the western part of the sandur and the majority of the groundwaters. These have lower concentrations of [Ca2++Mg2+], [Na++K+] and SO42- and ^34S values consistent with sulphate derived from the oxidation of igneous sulphides reflecting geochemical evolution and modified weathering processes from that of supraglacial streams. The significant influence of internal contributions of sulphate (rock-derived and geothermal) on Skeiðarársandur means this catchment buffers recent reductions in anthropogenic sulphur emissions.

  13. Micro-scale (1.5 microm) sulphur isotope analysis of contemporary and early Archean pyrite.

    PubMed

    Nishizawa, Manabu; Maruyama, Shigenori; Urabe, Tetsuro; Takahata, Naoto; Sano, Yuji

    2010-05-30

    We present a method for in situ sulphur (S) isotopic analysis of significantly small areas (1.5 microm in diameter) in pyrite using secondary ion mass spectrometry (NanoSIMS) to interpret microbial sulphur metabolism in the early earth. We evaluated the precision and accuracy of S isotopic ratios obtained by this method using hydrothermal pyrite samples with homogeneous S isotopic ratios. The internal precision of the delta(34)S value was 1.5 per thousand at the level of 1 sigma of standard error (named 1SE) for a single spot, while the external reproducibility was estimated to be 1.6 per thousand at the level of 1 sigma of standard deviation (named 1SD, n = 25). For each separate sample, the average delta(34)S value was comparable with that measured by a conventional method, and the accuracy was better than 2.3 per thousand. Consequently, the in situ method is sufficiently accurate and precise to detect the S isotopic variations of small sample of the pyrite (less than 20 microm) that occurs ubiquitously in ancient sedimentary rocks. This method was applied to measure the S isotopic distribution of pyrite within black chert fragments in early Archean sandstone. The pyrite had isotopic zoning with a (34)S-depleted core and (34)S-enriched rim, suggesting isotopic evolution of the source H(2)S from -15 to -5 per thousand. Production of H(2)S by microbial sulphate reduction (MSR) in a closed system provides a possible explanation for both the (34)S-depleted initial H(2)S and the progressive increase in the delta(34)S(H2S) value. Although more extensive data are necessary to strengthen the explanation for the origin of the MSR, the results show that the S isotopic distribution within pyrite crystals may be a key tracer for MSR activity in the early earth. PMID:20411578

  14. VizieR Online Data Catalog: Are infrared dark clouds really quiescent? (Feng+, 2016)

    NASA Astrophysics Data System (ADS)

    Feng, S.; Beuther, H.; Zhang, Q.; Henning, T.; Linz, H.; Ragan, S.; Smith, R.

    2016-05-01

    All fits files are molecular line integrated intensity maps in G28.34S, IRDC18530, IRDC18306, and IRDC 18308 (Fig.3 in the paper). The maps unit is the intensity integrations (Kkm/s) over the velocity dispersion of each line. For the lines with <4σ detections, we only integrate a total of three channels around the system Vlsr at their rest frequencies. Files are named as "source"+"species"+".fits". G28.34S is abbreviated as "28", IRDC18306 is abbreviated as "06", IRDC18308 is abbreviated as "08", and IRDC18530 is abbreviated as "30". (2 data files).

  15. Stable sulfur isotope partitioning during simulated petroleum formation as determined by hydrous pyrolysis of Ghareb Limestone, Israel

    USGS Publications Warehouse

    Amrani, A.; Lewan, M.D.; Aizenshtat, Zeev

    2005-01-01

    Hydrous pyrolysis experiments at 200 to 365??C were carried out on a thermally immature organic-rich limestone containing Type-IIS kerogen from the Ghareb Limestone in North Negev, Israel. This work focuses on the thermal behavior of both organic and inorganic sulfur species and the partitioning of their stable sulfur isotopes among organic and inorganic phases generated during hydrous pyrolyses. Most of the sulfur in the rock (85%) is organic sulfur. The most dominant sulfur transformation is cleavage of organic-bound sulfur to form H2 S(gas). Up to 70% of this organic sulfur is released as H2S(gas) that is isotopically lighter than the sulfur in the kerogen. Organic sulfur is enriched by up to 2??? in 34S during thermal maturation compared with the initial ??34S values. The ??34S values of the three main organic fractions (kerogen, bitumen and expelled oil) are within 1??? of one another. No thermochemical sulfate reduction or sulfate formation was observed during the experiments. The early released sulfur reacted with available iron to form secondary pyrite and is the most 34S depleted phase, which is 21??? lighter than the bulk organic sulfur. The large isotopic fractionation for the early formed H2S is a result of the system not being in equilibrium. As partial pressure of H2S(gas) increases, retro reactions with the organic sulfur in the closed system may cause isotope exchange and isotopic homogenization. Part of the ??34S-enriched secondary pyrite decomposes above 300??C resulting in a corresponding decrease in the ??34S of the remaining pyrite. These results are relevant to interpreting thermal maturation processes and their effect on kerogen-oil-H2S-pyrite correlations. In particular, the use of pyrite-kerogen ??34S relations in reconstructing diagenetic conditions of thermally mature rocks is questionable because formation of secondary pyrite during thermal maturation can mask the isotopic signature and quantity of the original diagenetic pyrite. The

  16. Sedimentary sulfur geochemistry of the Paleogene Green River Formation, western USA: Implications for interpreting depositional and diagenetic processes in saline alkaline lakes

    NASA Astrophysics Data System (ADS)

    Tuttle, Michele L.; Goldhaber, Martin B.

    1993-07-01

    The sulfur geochemistry of the lacustrine Paleogene Green River Formation (Colorado, Utah, and Wyoming, USA) is unlike that of most marine and other lacustrine rocks. Distinctive chemical, isotopic, and mineralogical characteristics of the formation are pyrrhotite and marcasite, high contents of iron mineral sulfides strikingly enriched in 34S, cyclical trends in sulfur abundance and δ 34S values, and long-term evolutionary trends in δ 34S values. Analyses that identified and quantified these characteristics include carbonate-free abundance of organic carbon (0.13-47 wt%), total iron (0.31-13 wt%), reactive iron (>70% of total iron), total sulfur (0.02-16 wt%), acid-volatile monosulfide (S Av), disulfide (S Di > 70% of total sulfur), sulfate (S SO4) and organosulfur (S Org); isotopic composition of separated sulfur phases (δ 34S Di,Av up to +49‰); and mineralogy, morphology and paragenesis of sulfide minerals. Mineralogy, morphology, δ 34S Di,Av, and δ 34S Org have a distinctive relation, reflecting variable and unique depositional and early diagenetic conditions in the Green River lakes. When the lakes were brackish, dissimilatory sulfate-reducing bacteria in the sediment produced H 2S, which initially reacted with labile iron to form pyrite framboids and more gradually with organic matter to form organosulfur compounds. During a long-lived stage of saline lake water, the amount of sulfate supplied by inflow decreased and alkalinity and pH of lake waters increased substantially. Extensive bacterial sulfate reduction in the water column kept lake waters undersaturated with sulfate minerals. A very high H 2S:SO 4 ratio developed in stagnant bottom water aided by the high pH that kinetically inhibited iron sulfidization. Progressive removal of H 2S by coeval formation of iron sulfides and organosulfur compounds caused the isotopic composition of the entire dissolved sulfur reservoir to evolve to δ 34S values much greater than that of inflow sulfate, which is

  17. Origin of stratiform sediment-hosted manganese carbonate ore deposits: Examples from Molango, Mexico, and TaoJiang, China

    USGS Publications Warehouse

    Okita, P.M.; Shanks, Wayne C., III

    1992-01-01

    Carbonate and sulfide minerals from the Molango, Mexico, and TaoJiang, China, Mn deposits display similar and distinctive ??34S and ??13C patterns in intervals of manganese carbonate mineralization. ??13C-values for Mn-bearing carbonate range from -17.8 to +0.5??? (PDB), with the most negative values occurring in high-grade ore zones that are composed predominantly of rhodochrosite. In contrast, calcite from below, within and above Mn-carbonate zones at Molango has ??13C???0??? (PDB). Markedly negative ??13C data indicate that a large proportion of the carbon in Mn-carbonates was derived from organic matter oxidation. Diagenetic reactions using MnO2 and SO2-4 to oxidize sedimentary organic matter were the principle causes of such 12C enrichment. Pyrite content and sulfide ?? 34S-values also show distinctive variations. In unmineralized rocks, very negative ??34S-values (avg. < -21??? CDT) and abundant pyrite content suggest that pyrite formed from diagenetic, bacteriogenic sulfate reduction. In contrast, Mn-bearing horizons typically contain only trace amounts of pyrite (e.g., <0.5 wt% S with ??34S-values 34S-enriched, in some cases to nearly the value for contemporaneous seawater. 34S-enriched pyrite from the Mn-carbonate intervals indicates sulfide precipitation in an environment that underwent extensive SO2-4 reduction, and was largely a closed system with regard to exchange of sulfate and dissolved sulfide with normal seawater. The occasional occurrence of 34S-depleted pyrite within Mn-carbonate zones dominated by 34S-enriched pyrite is evidence that closed-system conditions were intermittent and limited to local pore waters and did not involve entire sedimentary basins. Mn-carbonate precipitation may have occluded porosity in the surficial sediments, thus establishing an effective barrier to SO2-4 exchange with overlying seawater. Similar isotopic and mineralogic characteristics from both the Molango and TaoJiang deposits, widely separated in geologic time and

  18. Reaction mechanism underlying the in vitro transformation of thioarsenicals

    SciTech Connect

    Naranmandura, Hua; Suzuki, Noriyuki; Suzuki, Kazuo T.

    2008-09-15

    Thioarsenicals have been paid much attention due to the toxicity of arsenic, since some of them are highly toxic and commonly found in the urine of mammals. We previously reported that thioarsenicals might be produced in red blood cells (RBCs). Here, we further characterized the mechanism underlying the production and metabolism of thioarsenicals in RBCs using {sup 34}S-labeled dimethylmonothioarsinic acid ({sup 34}S-DMMTA{sup V}) and purified rat hemoglobin (Hb) or a rat RBC lysate. {sup 34}S-DMMTA{sup V} did not bind to Hb on incubation with purified rat Hb, remaining in its original form. However, when {sup 34}S-DMMTA{sup V} was incubated with a rat RBC lysate, only arsenic, i.e., not sulfur ({sup 34}S), was detected in a form bound to Hb (As-Hb). In addition, another arsenic product containing sulfur ({sup 34}S) in the molar ratio of {sup 34}S/As = 2 was detected, which was assigned as dimethyldithioarsinic acid (DMDTA{sup V}), suggesting that arsenic does not bind to Hb in the form of {sup 34}S-DMMTA{sup V} but does so in the form of dimethylarsinous acid (DMA{sup III}). Namely, DMMTA{sup V} appeared to be hydrolyzed into dimethylarsinic acid (DMA{sup V}) and H{sup 34}S{sup -}, and the released H{sup 34}S{sup -} reacted with DMMTA{sup V} to produce DMDTA{sup V}. Thus, DMMTA{sup V} was transformed into DMDTA{sup V} and DMA{sup V} (2DMMTA{sup V} - > DMDTA{sup V} + DMA{sup V}), the latter product being reduced to DMA{sup III} in the presence of GSH and bound to Hb. In a separate experiment, {sup 34}S-DMMTA{sup V} was incubated with sulfide (Na{sub 2}S) and GSH. Although DMMTA{sup V} was not transformed into DMDTA{sup V} in the presence of only Na{sub 2}S or GSH, it was transformed into DMDTA{sup V} in the presence of both Na{sub 2}S and GSH. Our results suggest that DMMTA{sup V} is hydrolyzed enzymatically into DMA{sup V} and sulfide, the former being reduced to DMA{sup III} and bound to Hb, and the latter reacting with DMMTA{sup V} to yield DMDTA{sup V}. Thus

  19. Probing dynamics of fusion reactions through cross-section and spin distribution measurement

    NASA Astrophysics Data System (ADS)

    Kaur, Maninder; Behera, B. R.; Singh, Gulzar; Singh, Varinderjit; Madhavan, N.; Muralithar, S.; Nath, S.; Gehlot, J.; Mohanto, G.; Mukul, Ish; Siwal, D.; Thakur, M.; Kapoor, K.; Sharma, P.; Banerjee, T.; Jhingan, A.; Varughese, T.; Bala, Indu; Nayak, B. K.; Saxena, A.; Chatterjee, M. B.; Stevenson, P. D.

    2016-05-01

    Present work aims to explicate the effect of entrance channel mass asymmetry on fusion dynamics for the Compound Nucleus 80Sr populated through two different channels, 16O+64Zn and 32S+48Ti, using cross-section and spin distribution measurements as probes. The evaporation spectra studies for these systems, reported earlier indicate the presence of dynamical effects for mass symmetric 32S+48Ti system.The CCDEF and TDHF calculations have been performed for both the systems and an attempt has been made to explain the reported deviations in the α-particle spectrum for the mass symmetric system.

  20. MASTER-Tunka: bright SN in edge-on UGC05919

    NASA Astrophysics Data System (ADS)

    Gress, O.; Lipunov, V.; Budnev, N.; Ivanov, K.; Tiurina, N.; Gorbovskoy, E.; Balanutsa, P.; Kuznetsov, A.; Vlasenko, D.; Kornilov, V.; Kuvshinov, D.; Shumkov, V.; Kochutina, N.; Shurpakov, S.

    2016-06-01

    MASTER-Tunka auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 349171 ) discovered OT source at (RA, Dec) = 10h 49m 16.33s +58d 20m 39.9s on 2016-06-29.68150 UT. The PSN unfiltered magnitude is 15.9m (limit 18.7m).

  1. Sources of Resistance to Pepino Mosaic Virus in Solanum habrochaites (Lycopersicon hirsutum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pepino mosaic virus (PepMV) is an emerging disease on greenhouse tomato. A major tomato germplasm core collection was evaluated for its resistance against PepMV. These accessions included 23 Solanum lycopersicum L., 8 S. pimpinellifolium L., 33 S. peruvianum L., 18 S. chilense (Dunal) Reiche, and ...

  2. Master-Iac Master-Saao 2 bright OTs

    NASA Astrophysics Data System (ADS)

    Gress, O.; Pogrosheva, T.; Lipunov, V.; Lopez, R. Rebolo; Buckley, D.; Gorbovskoy, E.; Tiurina, N.; Balanutsa, P.; Gorbunov, I.; Kuznetsov, A.; Popova, E.; Kuvshinov, D.; Serra-Ricart, M.; Israelian, G.; Potter, S.; Kniazev, A.

    2016-05-01

    MASTER-IAC auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 349171 ) discovered OT source at (RA, Dec) = 00h 10m 21.33s +73d 15m 16.5s on 2016-05-24.18141 UT. The OT unfiltered magnitude is 15.7m (limit 18.1m).

  3. Sulfur isotope variability of oceanic DMSP generation and its contributions to marine biogenic sulfur emissions

    PubMed Central

    Oduro, Harry; Van Alstyne, Kathryn L.; Farquhar, James

    2012-01-01

    Oceanic dimethylsulfoniopropionate (DMSP) is the precursor to dimethylsulfide (DMS), which plays a role in climate regulation through transformation to methanesulfonic acid (MSA) and non-seasalt sulfate (NSS-SO42−) aerosols. Here, we report measurements of the abundance and sulfur isotope compositions of DMSP from one phytoplankton species (Prorocentrum minimum) and five intertidal macroalgal species (Ulva lactuca, Ulva linza, Ulvaria obscura, Ulva prolifera, and Polysiphonia hendryi) in marine waters. We show that the sulfur isotope compositions (δ34S) of DMSP are depleted in 34S relative to the source seawater sulfate by ∼1–3‰ and are correlated with the observed intracellular content of methionine, suggesting a link to metabolic pathways of methionine production. We suggest that this variability of δ34S is transferred to atmospheric geochemical products of DMSP degradation (DMS, MSA, and NSS-SO42−), carrying implications for the interpretation of variability in δ34S of MSA and NSS-SO42− that links them to changes in growth conditions and populations of DMSP producers rather than to the contributions of DMS and non-DMS sources. PMID:22586117

  4. Source of arsenic-bearing pyrite in southwestern Vermont, USA: sulfur isotope evidence.

    PubMed

    Mango, Helen; Ryan, Peter

    2015-02-01

    Arsenic-bearing pyrite is the source of arsenic in groundwater produced in late Cambrian and Ordovician gray and black slates and phyllites in the Taconic region of southwestern Vermont, USA. The aim of this study is to analyze the sulfur isotopic composition of this pyrite and determine if a relationship exists between pyrite δ(34)S and arsenic content. Pyrite occurs in both sedimentary/diagenetic (bedding-parallel layers and framboids) and low-grade metamorphic (porphyroblast) forms, and contains up to >2000 ppm As. The sulfur isotopic composition of arsenic-bearing pyrite ranges from -5.2‰ to 63‰. In the marine environment, the sulfur in sedimentary pyrite becomes increasingly enriched in (34)S as the geochemical environment becomes increasingly anoxic. There is a positive correlation between δ(34)S and arsenic content in the Taconic pyrite, suggesting that uptake of arsenic by pyrite increased as the environment became more reducing. This increased anoxia may have been due to a rise in sea level and/or tectonic activity during the late Cambrian and Ordovician. Low-grade metamorphism appears to have little effect on sulfur isotope composition, but does correlate with lower arsenic content in pyrite. New groundwater wells drilled in this region should therefore avoid gray and black slates and phyllites that contain sedimentary/diagenetic pyrite with heavy δ(34)S values. PMID:24726513

  5. Sulfur contents and sulfur-isotope compositions of thiotrophic symbioses in bivalve molluscs and vestimentiferan worms

    USGS Publications Warehouse

    Vetter, R.D.; Fry, B.

    1998-01-01

    Total sulfur (S(TOT)), elemental sulfur (S??) and sulfur-isotope compositions (??34S) of marine animals were analyzed to determine whether these chemical characteristics could help distinguish animals with a sulfur-based, thiotrophic nutrition from animals whose nutrition is based on methanotrophy or on more normal consumption of phytoplankton-derived organic matter. The presence of S??was almost entirely confined to the symbiont-containing tissues of thiotrophs, but was sometimes undetectable in thiotrophic species where sulfide availability was probably low. When S??contents were subtracted, the remaining tissue-sulfur concentrations were similar for all nutritional groups. ??34S values were typically lower for thiotrophs than for other groups, although there was overlap in methanotroph and thiotroph values at some sites. Field evidence supported the existence of small to moderate (1 to 10???)34S fractionations in the uptake of sulfides and metabolism of thiosulfate. In general, a total sulfur content of >3% dry weight, the presence of elemental sulfur, and ??34S values less than + 5??? can be used to infer a thiotrophic mode of nutrition.

  6. Concrete under sulphate attack: an isotope study on sulphur sources.

    PubMed

    Mittermayr, Florian; Bauer, Christoph; Klammer, Dietmar; Böttcher, Michael E; Leis, Albrecht; Escher, Peter; Dietzel, Martin

    2012-01-01

    The formation of secondary sulphate minerals such as thaumasite, ettringite and gypsum is a process causing severe damage to concrete constructions. A major key to understand the complex reactions, involving concrete deterioration is to decipher the cause of its appearance, including the sources of the involved elements. In the present study, sulphate attack on the concrete of two Austrian tunnels is investigated. The distribution of stable sulphur isotopes is successfully applied to decipher the source(s) of sulphur in the deteriorating sulphate-bearing minerals. Interestingly, δ(34)S values of sulphate in local groundwater and in the deteriorating minerals are mostly in the range from+14 to+27 ‰. These δ(34)S values match the isotope patterns of regional Permian and Triassic marine evaporites. Soot relicts from steam- and diesel-driven trains found in one of the tunnels show δ(34)S values from-3 to+5 ‰, and are therefore assumed to be of minor importance for sulphate attack on the concretes. In areas of pyrite-containing sedimentary rocks, the δ(34)S values of sulphate from damaged concrete range between-1 and+11 ‰. The latter range reflects the impact of sulphide oxidation on local groundwater sulphate. PMID:22321257

  7. STABLE ISOTOPE STUDIES ON THE USE OF MARINE-DERIVED NUTRIENTS BY COHO SALMON JUVENILES IN AN OREGON COAST RANGE STREAM

    EPA Science Inventory

    We are using stable isotopes (13C, 15N, 34S) to study the use of salmon carcasses, eggs and fry by over-wintering coho juveniles in two streams of the Oregon Coast Range. Our work is paired with detailed data gathering on stream habitat condition, temperature, chemistry and PIT-t...

  8. Sulfur isotope variability of oceanic DMSP generation and its contributions to marine biogenic sulfur emissions.

    PubMed

    Oduro, Harry; Van Alstyne, Kathryn L; Farquhar, James

    2012-06-01

    Oceanic dimethylsulfoniopropionate (DMSP) is the precursor to dimethylsulfide (DMS), which plays a role in climate regulation through transformation to methanesulfonic acid (MSA) and non-seasalt sulfate (NSS-SO(4)(2-)) aerosols. Here, we report measurements of the abundance and sulfur isotope compositions of DMSP from one phytoplankton species (Prorocentrum minimum) and five intertidal macroalgal species (Ulva lactuca, Ulva linza, Ulvaria obscura, Ulva prolifera, and Polysiphonia hendryi) in marine waters. We show that the sulfur isotope compositions (δ(34)S) of DMSP are depleted in (34)S relative to the source seawater sulfate by ∼1-3‰ and are correlated with the observed intracellular content of methionine, suggesting a link to metabolic pathways of methionine production. We suggest that this variability of δ(34)S is transferred to atmospheric geochemical products of DMSP degradation (DMS, MSA, and NSS-SO(4)(2-)), carrying implications for the interpretation of variability in δ(34)S of MSA and NSS-SO(4)(2-) that links them to changes in growth conditions and populations of DMSP producers rather than to the contributions of DMS and non-DMS sources. PMID:22586117

  9. Sulfur isotope variability of oceanic DMSP generation and its contributions to marine biogenic sulfur emissions

    NASA Astrophysics Data System (ADS)

    Oduro, Harry; Van Alstyne, Kathryn L.; Farquhar, James

    2012-06-01

    Oceanic dimethylsulfoniopropionate (DMSP) is the precursor to dimethylsulfide (DMS), which plays a role in climate regulation through transformation to methanesulfonic acid (MSA) and non-seasalt sulfate (NSS-SO42-) aerosols. Here, we report measurements of the abundance and sulfur isotope compositions of DMSP from one phytoplankton species (Prorocentrum minimum) and five intertidal macroalgal species (Ulva lactuca, Ulva linza, Ulvaria obscura, Ulva prolifera, and Polysiphonia hendryi) in marine waters. We show that the sulfur isotope compositions (δ34S) of DMSP are depleted in 34S relative to the source seawater sulfate by ∼1-3‰ and are correlated with the observed intracellular content of methionine, suggesting a link to metabolic pathways of methionine production. We suggest that this variability of δ34S is transferred to atmospheric geochemical products of DMSP degradation (DMS, MSA, and NSS-SO42-), carrying implications for the interpretation of variability in δ34S of MSA and NSS-SO42- that links them to changes in growth conditions and populations of DMSP producers rather than to the contributions of DMS and non-DMS sources.

  10. Isotope evidence for secondary sulfide precipitation along the Marsyandi River, Nepal, Himalayas

    NASA Astrophysics Data System (ADS)

    Turchyn, Alexandra V.; Tipper, Edward T.; Galy, Albert; Lo, Jun-Kai; Bickle, Mike J.

    2013-07-01

    We present sulfur and oxygen isotope data from 41 samples of dissolved riverine sulfate from along 65 km of the Marsyandi River in the Northern Himalayas. Coupled sulfur and oxygen isotopic composition of riverine sulfate (δ34S and δ18O respectively) yield unique constraints on the source of sulfur to the river system. The headwaters of the Marsyandi River have light δ34S and δ18O, which requires that the source of sulfate to the river is through the anoxic weathering of pyrite (likely via Fe3+). The δ34S and δ18O of sulfate in tributaries to the Marsyandi increase downstream, which could result either from inputs from evaporites or bacterial sulfate reduction with subsequent sulfide precipitation in warmer and wetter catchments; either of these processes could result in heavy δ34S and δ18O of the residual river sulfate. Elemental ratios such as Sr/Ca and Ca/SO4 suggest, as previous studies have also concluded, that evaporite weathering is not important in the Marsyandi River. We conclude that the isotope data is most consistent with the onset of bacterial sulfate reduction and secondary sulfide precipitation in the soils in the warmer and wetter downstream catchments. Our results have implications for understanding the source of sulfate to the ocean as well as the redox and acidity budget within rapidly eroding catchments.

  11. MONITORING FOOD WEB CHANGES IN TIDE-RESTORED SALT MARSHES: A CARBON STABLE ISOTOPE APPROACH

    EPA Science Inventory

    Primary producer (angiosperms, macroalgae, submerged aquatic vegetation), suspended particulate matter, and Fundulus heteroclitus isotope values (d13C , d15N, d34S) were examined to assess their use as an indicator for changes in food web support functions in tidally-restored sal...

  12. Use of sulphur and carbon stable-isotope composition of fish scales and muscles to identify the origin of fish

    NASA Astrophysics Data System (ADS)

    Trembaczowski, Andrzej

    2011-01-01

    δ34S and δ13C analyses were used to determine the origin of trout specimens. The isotope record of their scales and muscles are compared with a database previously obtained from wild- and reared fish coming from Polish rivers and pond farms. The comparison made it possible to find out whether the trout were wild or reared.

  13. The sulphur stable isotope compositions of urban sources and atmospheric particles (PM2.5 & PM10) from Paris (France)

    NASA Astrophysics Data System (ADS)

    Widory, D.; Landry, J.; Helie, J.; Ravelomanantsoa, H.

    2013-12-01

    Sulphur (S) in atmospheric particles in the environment can be derived from a variety of primary sources and cycled through numerous secondary processes, complicating identification of its origin. Using the PM10 fraction of aerosols from Paris and its vicinity, we are investigating the suitability of sulphur stable isotope compositions (δ34S) as tracers of origins and processes affecting the atmospheric S budget. Characterization of S isotope compositions of emissions from the different potential sources (e.g. waste incinerators, coal-fired power plants, metal refining plants, road traffic and heating sources) shows these are clearly discriminated by specific coupled S-δ34S isotope signatures. While S concentrations vary from 0.7 to 11.5%, δ34S display a large range of values from -2.2 and 13.4‰. PM10 samples from Paris and its vicinity show that S is usually present at low levels, around 1 μg.m-3 in average, but that concentrations as high as 100 μg.m-3 can punctually be observed. By the time of the conference, we will have analysed and interpreted the corresponding δ34S in order to help elucidate the origin(s) of sulphur in the atmosphere of the city.

  14. Cretaceous shales from the western interior of North America: sulfur/carbon ratios and sulfur-isotope composition.

    USGS Publications Warehouse

    Gautier, D.L.

    1986-01-01

    Sulphur/carbon ratios in cores of selected Cretaceous marine shales average 0.67, a value greater than that observed in recent marine sediments and much higher than global values calculated for the Cretaceous. This may be ascribed to generally low levels of bioturbation and enhanced efficiency of sulphate reduction due to low oxygen levels in Cretaceous seaways. Isotopic compositions of pyrite sulphur vary systematically with level of oxygenation of the depositional environment and therefore with organic carbon abundance and type of organic matter. Samples with >4% organic carbon are extremely depleted in 34S (mean delta 34S -31per mille) and contain hydrogen-rich organic matter. Samples containing <1.5% organic carbon display relatively 'heavy' but wide-ranging delta 34S values (-34.6 to +16.8per mille) and contain hydrogen-poor organic matter. Samples with intermediate amounts of organic carbon have average delta 34S of -25.9per mille and contain both types of organic matter. Relations between the nature of these shales, and their sedimentation rate and depositional environment are discussed.-L.C.H.

  15. Implications of 3.2 Ga deep seawater from sulfur isotopic analysis of barite crystals in Pilbara, Western Australia.

    NASA Astrophysics Data System (ADS)

    Miki, T.; Kiyokawa, S.; Takahata, N.; Ishida, A.; Ito, T.; Ikehara, M.; Sano, Y.

    2015-12-01

    Sulfur isotopic (δ34S) analysis is used as one of the methods of Precambrian environmental reconstruction. It has been pointed out that δ34S fluctuations of sulfate and sulfide have close relationship with rise of oxygen level and increase in biological activity of sulfate reducing bacteria. For example, the difference of δ34S between sulfate and sulfide is small in Archean while it gets larger after evolution of oxygen level and biological activity (e.g. Canfield and Farquhar, 2009).  However, evidence of δ34S difference between sulfate and sulfide in Archean is scarce. In this study, we focused on barite and pyrite occurred at the layer in the 3.2 Ga Dixon Island Formation in coastal Pilbara terrane, Western Australia.  We found pyrites in from the bottom of the Black Chert Member to the Varicolored Chert Member of the Dixon Island Formation. Particularly, we can see pyrite layers of a few millimeters thick which make an alternate layers with black chert layers in the Varicolored Chert Member. The bulk δ34S values of these layers are -10.1~+26.8‰ (Sakamoto, 2010MS) and micro-meter scale heterogeneity of δ34S can be seen in minute spherical shell pyrite which was formed at early stage of diagenesis (Miki, 2015MS).  On the other hand, barite layers are remained in the lower part of the Black Chert Member in the Dixon Island Formation. In these layers, columnar quartz crystals were representative which are considered to be a pseudomorph of barite. Such equigranular occurrences of barite are typical character in submarine hydrothermal system (Kiyokawa et al., 2006). There exist small crystals of barite (less than 200 um in diameter) which are expected to be remnants of original barite. We performed microscale sulfur isotope analyses using a NanoSIMS.  As a preliminary result, we obtained δ34S value of +3.4~+9.1‰ (n=11). These values are similar to the reported values of barite which are considered to be a hydrothermal origin in 3.47 Ga North Pole

  16. Sulfur, carbon, and oxygen isotope variations in submarine hydrothermal deposits of Guaymas Basin, Gulf of California, USA

    USGS Publications Warehouse

    Peter, J.M.; Shanks, Wayne C., III

    1992-01-01

    Sulfur, carbon, and oxygen isotope values were measured in sulfide, sulfate, and carbonate from hydrothermal chimney, spire, and mound samples in the southern trough of Guaymas Basin, Gulf of California, USA. ??34S values of sulfides range from -3.7 to 4.5%. and indicate that sulfur originated from several sources: 1. (1) dissolution of 0??? sulfide contained within basaltic rocks, 2. (2) thermal reduction of seawater sulfate during sediment alteration reactions in feeder zones to give sulfide with positive ??34S, and 3. (3) entrainment or leaching of isotopically light (negative-??34S) bacteriogenic sulfide from sediments underlying the deposits. ??34S of barite and anhydrite indicate sulfur derivation mainly from unfractionated seawater sulfate, although some samples show evidence of sulfate reduction and sulfide oxidation reactions during mixing within chimneys. Oxygen isotope temperatures calculated for chimney calcites are in reasonable agreement with measured vent fluid temperatures and fluid inclusion trapping temperatures. Hydrothermal fluids that formed calcite-rich chimneys in the southern trough of Guaymas Basin were enriched in 18O with respect to seawater by about 2.4??? due to isotopic exchange with sedimentary and/or basaltic rocks. Carbon isotope values of calcite range from -9.6 to -14.0??? ??34CpDB, indicating that carbon was derived in approximately equal quantities from the dissolution of marine carbonate minerals and the oxidation of organic matter during migration of hydrothermal fluid through the underlying sediment column. Statistically significant positive, linear correlations of ??34S, ??34C, and ??18O of sulfides and calcites with geographic location within the southern trough of Guaymas Basin are best explained by variations in water/rock ( w r) ratios or sediment reactivity within subsurface alteration zones. Low w r ratios and the leaching of detrital carbonates and bacteriogenic sulfides at the southern vent sites result in relatively

  17. Effect of sulfidogenesis cycling on the biogeochemical process in arsenic-enriched aquifers in the Lanyang Plain of Taiwan: Evidence from a sulfur isotope study

    NASA Astrophysics Data System (ADS)

    Kao, Yu-Hsuan; Liu, Chen-Wuing; Wang, Pei-Ling; Liao, Chung-Min

    2015-09-01

    This study evaluated the biogeochemical interactions between arsenic (As) and sulfur (S) in groundwater to understand the natural and anthropogenic influences of S redox processes on As mobilization in the Lanyang Plain, Taiwan. Cl- and the sulfate isotopic composition (δ34S[SO4]) were selected as conservative tracers. River water and saline seawater were considered as end members in the binary mixing model. Thirty-two groundwater samples were divided into four types of groundwater (I, pyrite-oxidation; II, iron- and sulfate-reducing; III, sulfate-reducing; and IV, anthropogenic and others). The binary mixing model coupled with discriminant analysis was applied to yield a classification with 97% correctness, indicating that the DO/ORP values and δ34S[SO4] and Fe2+ concentrations are effective redox-sensitive indicators. Type I groundwater is mostly located in a mountainous recharge area where pyrite oxidation