Academic Journal
Experimental evidence for the hydrothermal formation of native sulfur by synproportionation
| العنوان: | Experimental evidence for the hydrothermal formation of native sulfur by synproportionation |
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| المؤلفون: | Kürzinger, Victoria, Hansen, Christian T., Strauss, Harald, Wu, Shijun, Bach, Wolfgang |
| المصدر: | Frontiers in Earth Science ; volume 11 ; ISSN 2296-6463 |
| بيانات النشر: | Frontiers Media SA |
| سنة النشر: | 2023 |
| المجموعة: | Frontiers (Publisher - via CrossRef) |
| الوصف: | Elemental sulfur (S 0 ) is known to form in submarine acid-sulfate vents by disproportionation of magmatic SO 2 . S 0 formed upon disproportionation shows δ 34 S S values considerably lower than the influxing magmatic SO 2 , which results in δ 34 S S values typically <0‰. The peculiar occurrence of isotopically heavy sulfur in the Kemp Caldera hydrothermal system (δ 34 S S > 5‰) and Niua North (δ 34 S S = 3.1‰) led to the suggestion that disproportionation is not the only sulfur forming process in submarine hydrothermal systems. We conducted hydrothermal experiments to investigate if synproportionation of SO 2 and H 2 S can explain the occurrence and isotopic composition of S 0 observed in some vent fields. Provided that SO 2 and H 2 S are both abundant, this formation mechanism is thermodynamically conceivable, but it has not yet been demonstrated experimentally that this process actually takes place in submarine hydrothermal systems. We conducted the experiments in collapsible Ti-cells under pT-conditions (20–30 MPa, 220°C) that are relevant to S 0 formation in submarine hydrothermal systems. We used starting concentrations of 10 mM sulfite and 20 mM sulfide of known isotopic composition. Under acidic conditions (pH 25 °C = 1.2), S 0 was the most abundant reaction product, but small amounts of sulfate were also produced. A Rayleigh fractionation model was applied to determine the isotopic composition of SO 4 2– , SO 2 , H 2 S and S 0 expected to form by SO 2 disproportionation, H 2 S oxidation, and SO 2 –H 2 S synproportionation. The sulfur isotopic signatures of the sulfur produced in the experiments can only be explained by synproportionation of sulfite and sulfide. These results provide strong evidence that synproportionation is likely responsible for exceptionally high δ 34 S S values observed in S 0 from some arc/back-arc hydrothermal environments, like the Kemp Caldera in the South Sandwich arc. Coeval degassing of H 2 S and SO 2 is likely required to have this particular reaction dominate ... |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | unknown |
| DOI: | 10.3389/feart.2023.1132794 |
| DOI: | 10.3389/feart.2023.1132794/full |
| الاتاحة: | http://dx.doi.org/10.3389/feart.2023.1132794 https://www.frontiersin.org/articles/10.3389/feart.2023.1132794/full |
| Rights: | https://creativecommons.org/licenses/by/4.0/ |
| رقم الانضمام: | edsbas.7955C792 |
| قاعدة البيانات: | BASE |
| DOI: | 10.3389/feart.2023.1132794 |
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