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  • 1
    Electronic Resource
    Electronic Resource
    Quantitative preparation of sulfur dioxide, for sulfur-34/sulfur-32 analyses, from sulfides by combustion with cuprous oxide (1975)
    s.l. : American Chemical Society
    Analytical chemistry 47 (1975), S. 1179-1181 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60357a026
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  • 2
    Electronic Resource
    Electronic Resource
    Geochemical and isotopic evidence for seawater contamination of the hydrothermal system of Taal Volcano, Luzon, the Philippines (1998)
    Springer
    Bulletin of volcanology 59 (1998), S. 562-576 
    Details
    ISSN: 1432-0819
    Keywords: Key words Hydrothermal system ; Fluid geochemistry ; Stable isotopes ; Geochemical monitoring ; Taal Volcano
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The hydrologic structure of Taal Volcano has favored development of an extensive hydrothermal system whose prominent feature is the acidic Main Crater Lake (pH〈3) lying in the center of an active vent complex, which is surrounded by a slightly alkaline caldera lake (Lake Taal). This peculiar situation makes Taal prone to frequent, and sometimes catastrophic, hydrovolcanic eruptions. Fumaroles, hot springs, and lake waters were sampled in 1991, 1992, and 1995 in order to develop a geochemical model for the hydrothermal system. The low-temperature fumarole compositions indicate strong interaction of magmatic vapors with the hydrothermal system under relatively oxidizing conditions. The thermal waters consist of highly, moderately, and weakly mineralized solutions, but none of them corresponds to either water–rock equilibrium or rock dissolution. The concentrated discharges have high Na contents (〉3500 mg/kg) and low SO4/Cl ratios (〈0.3). The Br/Cl ratio of most samples suggests incorporation of seawater into the hydrothermal system. Water and dissolved sulfate isotopic compositions reveal that the Main Crater Lake and spring discharges are derived from a deep parent fluid (T≈300  °C), which is a mixture of seawater, volcanic water, and Lake Taal water. The volcanic end member is probably produced in the magmatic-hydrothermal environment during absorption of high-temperature gases into groundwater. Boiling and mixing of the parent water give rise to the range of chemical and isotopic characteristics observed in the thermal discharges. Incursion of seawater from the coastal region to the central part of the volcano is supported by the low water levels of the lakes and by the fact that Lake Taal was directly connected to the China sea until the sixteenth century. The depth to the seawater-meteoric water interface is calculated to be 80 and 160 m for the Main Crater Lake and Lake Taal, respectively. Additional data are required to infer the hydrologic structure of Taal. Geochemical surveillance of the Main Crater Lake using the SO4/Cl, Na/K, or Mg/Cl ratio cannot be applied straightforwardly due to the presence of seawater in the hydrothermal system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004450050210
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  • 3
    Electronic Resource
    Electronic Resource
    Olivine phenocrysts in some Cameroonian Basalts—implications for primary magma composition (1991)
    Springer
    Mineralogy and petrology 44 (1991), S. 253-269 
    Details
    ISSN: 1438-1168
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Die chemische Zusammensetzung von Olivin Phenokristallen wurde in 13 Basalt-Proben, die vom Zentralteil .des Kamerun-Vulkangürtels stammen, bestimmt, um Hinweise auf die Zusammensetzung der primären Olivineinsprenglinge and des primären Magmas zu erlangen. Die Mg/(Mg + Fe) Verhältnisse der Olivine reichen bis 0.91, obwohl viefle dieser Mg-Olivine auf Grund textureller Kriterien als aus Peridotit-Einschlüssen stammende Xenokristalle zu identifizieren sind. Die Mg/(Mg + Fe) Verhältnsse der Hauptmasse der Olivin-Phenokristalle liegen im Bereich von 0.87 bis 0.88, die Ni0 Gehalte zwischen 0.32 und 0.35 Gew %. Die Ni0 gegen Mg/(Mg + Fe) Verhältnisse eignen sich zur Abschätzung der Zusammensetzung der primären Phenokristalle, solange die Mg/(Mg + Fe) Verhältnisse im Bereich von 0.88 bis 0.90 liegen. Die Zusammensetzung des Primärmagmas wurde mittels der Fe2+-Mg-Verteilung zwischen dem Magma und den sich mit dem Magma im Gleichgewicht befindlichen primären Olivinkristallen unter der Annahme eines Fe3+/Fe total Verhältnisses von 0.17–0.25, welches sich aus der Mg-Fe Verteilung zwischen Plagioklas und Grundmasse ergibt, bestimmt. Demnach ergibt sich für das primäre Magma der Kamerun Basalte ein MgO Gehalt von 13.5 + 4.0 Gew%. Dieser Wert ist mit der Zusammensetzung von Basalten mit höchsten MgO-Gehalten, wie sie bisher vom Kamerun-Vulkangürtel berichtet worden sind, vergleichbar.
    Notes: Summary The chemical composition of olivine phenocrysts was determined for 13 basaltic samples taken from the central part of the Cameroon Volcanic line to estimate the compositions of the primary olivine phenocrysts and the primary magmas. The Mg/(Mg + Fe) ratios of the olivines attain 0.91, though many of the magnesian olivines are identified on a textural basis as xenocrysts from peridotite inclusions. Most magnesian olivine phenocrysts have Mg/(Mg + Fe) ratios of 0.87–0.88 and NiO contents of 0.32–0.35 wt %. The NiO versus Mg/(Mg + Fe) ratios of the olivines can be used to estimate the compositions of the primary phenocrysts in a range of Mg/(Mg + Fe) = 0.88–0.90. Assuming the Fe(3)/(total Fe) ratios of the magmas are 0.17–0.25, which is estimated from the Fe-Mg partitioning between plagioclase and groundmass, the compositions of the primary magmas were obtained from the Fe2+-Mg partition equilibrium with the primary olivine phenocrysts. The primary magmas of the Cameroonian basalts have 13.5 ± 4.0 wt MgO, which is similar to the compositions of basalts with highest MgO contents reported so far from the Cameroon volcanic line.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01166966
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  • 4
    Electronic Resource
    Electronic Resource
    Sulfur isotope values in a forested catchment over four years: Evidence for oxidation and reduction processes (1999)
    Springer
    Biogeochemistry 44 (1999), S. 51-71 
    Details
    ISSN: 1573-515X
    Keywords: adsorption ; bacterial dissimilatory sulfate reduction ; dry deposition ; forested catchment ; Lake Gårdsjön ; isotopes ; oxidation of sulfur ; sulfate ; sulfur ; Sweden
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract A small catchment on the Swedish West Coast has been studied over four years to determine S dynamics by using S isotope ratios. A Norway spruce dominated forest covers the catchment, and small peat areas occur in the lower parts of the catchment. The runoff δ34SSO4 values varied both during the year, and from year to year. Over the period from February 1990 to December 1993, the δ34SSO4 values ranged from −1‰ to +11‰. Over the same period, the throughfall δ34SSO4 values ranged from +1‰ to +15‰. There was no correlation (r2 = 0.01; Pr(F) = 0.57) between δ34SSO4 values in throughfall and runoff. Since the only input of S to the catchment is atmospheric deposition, the long-term runoff S mass flux is controlled by the deposition. Therefore, processes in the catchment are responsible for the variation in the runoff δ34SSO4 values. During periods with 34SSO4 enriched runoff, bacterial dissimilatory SO42- reduction occurs in the catchment. After very dry periods, oxidation of this reduced S, which is 32S-enriched, can be traced in runoff. Previous studies of the catchment have not been able to distinguish between: 1) oxidation of reduced S and dry deposition, and 2) reduction and adsorption. From the current study, it can be concluded that adsorption and dry deposition cannot cause the observed variation in runoff δ34SSO4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006030008089
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  • 5
    Electronic Resource
    Electronic Resource
    Sulfur isotope values in a forested catchment over four years: Evidence for oxidation and reduction processes (1999)
    Springer
    Biogeochemistry 44 (1999), S. 51-71 
    Details
    ISSN: 1573-515X
    Keywords: adsorption ; bacterial dissimilatory sulfate reduction ; dry deposition ; forested catchment ; Lake Gårdsjön ; isotopes ; oxidation of sulfur ; sulfate ; sulfur ; Sweden
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract A small catchment on the Swedish West Coast has been studied over four years to determine S dynamics by using S isotope ratios. A Norway spruce dominated forest covers the catchment, and small peat areas occur in the lower parts of the catchment. The runoff $$\delta ^{34} S_{SO_4 } $$ values varied both during the year, and from year to year. Over the period from February 1990 to December 1993, the $$\delta ^{34} S_{SO_4 } $$ values ranged from — 1%. to +11%. Over the same period, the throughfall $$\delta ^{34} S_{SO_4 } $$ values ranged from +1%. to +15%. There was no correlation (r 2= 0.01; Pr(F)=0.57) between $$\delta ^{34} S_{SO_4 } $$ values in throughfall and runoff. Since the only input of S to the catchment is atmospheric deposition, the long-term runoff S mass flux is controlled by the deposition. Therefore, processes in the catchment are responsible for the variation in the runoff $$\delta ^{34} S_{SO_4 } $$ values. During periods with $$\delta ^{34} S_{SO_4 } $$ enriched runoff, bacterial dissimilatory SO 4 2− reduction occurs in the catchment. After very dry periods, oxidation of this reduced S, which is32S-enriched, can be traced in runoff. Previous studies of the catchment have not been able to distinguish between: 1) oxidation of reduced S and dry deposition, and 2) reduction and adsorption. From the current study, it can be concluded that adsorption and dry deposition cannot cause the observed variation in runoff $$\delta ^{34} S_{SO_4 } $$ .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00992998
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  • 6
    Electronic Resource
    Electronic Resource
    Historical atmospheric deposition in a Swedish mining area traced by S isotope ratios in soils (1999)
    Springer
    Water, air & soil pollution 110 (1999), S. 103-118 
    Details
    ISSN: 1573-2932
    Keywords: atmospheric deposition ; mining area ; SO2 emission ; soil ; sulfur isotopes ; Sweden
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Mining activities for almost thousand years have caused large S emissions in the Falun area, central Sweden. Since the beginning of the 20th century, the S deposition has decreased considerably. The soil S concentrations and S isotope compositions were analyzed for ΣS and adsorbed SO42- for three soil profiles close to the mining area in order to identify the soil S sources. The δ34S values were found to be different for ΣS and adsorbed SO42- and ranged from –3.7‰ to +2.6‰. In the B-horizon, the observed ΣS δ34S values (and hence calculated δ34S values for organic S) were mostly lower than those of the adsorbed SO42-. In the O-horizon, ΣS showed similar δ34S values as the adsorbed SO42- in the mineral soil. The adsorbed SO42- showed nearly constant δ34S values with depth. The δ34S values in the soils are interpreted to reflect a mixture of historical and modern deposition due to soil S circulation with no or negligible fractionation. The lower δ34S values of organic S in the B-horizon suggests preservation of acid deposition originating from mining activities back in time. The adsorbed SO42- in the mineral soil and the organic S in the O-horizon reflect a response to a new δ34S composition in the atmosphere due to fossil fuel burning during the 20th century.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005007821230
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  • 7
    Electronic Resource
    Electronic Resource
    Preparation of carbon dioxide from magnesite for isotopic analysis (1977)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 287 (1977), S. 310-311 
    Details
    ISSN: 1618-2650
    Keywords: Isotopenanalyse von Kohlenstoff, Sauerstoff in Magnesit ; Massenspektrometrie ; Freisetzung von CO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary Since the application of the isotope geochemical method to obtain information on the formation mechanism of magnesite deposits was considered promising, we have developed a method to prepare carbon dioxide from magnesite samples for oxygen and carbon isotope analyses, using phosphoric acid reaction at an elevated temperature of 95° C. Data showing the reproducibility of the method (better than ±0.2‰ for both carbon and oxygen) are presented. The oxygen isotope fractionation factor between the evolved CO2 and magnesite at 95° C is 1.0080.
    Notes: Zusammenfassung Mit dem Ziel, durch isotopen-geochemische Untersuchungen den Bildungsmechanismus von Magnesitablagerungen aufzuklären, wurde ein Verfahren zur Freisetzung von Kohlendioxid aus den Magnesitproben zur O- und C-Isotopenanalyse ausgearbeitet. Dazu dient die Reaktion mit Phosphorsäure bei 95° C. Die Reproduzierbarkeit ist besser als ±0,2‰ für beide Elemente. Der Fraktionierungsfaktor für das Sauerstoffisotop zwischen CO2 und Magnesit bei 95° C beträgt 1,0080.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00634505
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    Paper (German National Licenses)
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