Sulfide oxidation affects the preservation of sulfur isotope signals
| Autor: | Qingjun Guo, Alyssa Findlay, Xi Yang, Alexey Kamyshny, Khoren Avetisyan, André Pellerin, Valeria Boyko |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
010504 meteorology & atmospheric sciences Sulfide Isotope FRACTIONATION chemistry.chemical_element LOW-SULFATE Geology 010502 geochemistry & geophysics 01 natural sciences Sulfur LAKE BACTERIAL DISPROPORTIONATION chemistry 13. Climate action SYSTEMS Environmental chemistry 0105 earth and related environmental sciences |
| Zdroj: | Geology Findlay, A J, Boyko, V, Pellerin, A, Ayetisyan, K, Guo, Q, Yang, X & Kamyshny, A 2019, ' Sulfide oxidation affects the preservation of sulfur isotope signals ', Geology, vol. 47, no. 8, pp. 739-743 . https://doi.org/10.1130/G46153.1 |
| ISSN: | 0091-7613 |
| DOI: | 10.1130/g46153.1 |
| Popis: | The accumulation of oxygen in Earth’s atmosphere and oceans in the late Archean had profound implications for the planet’s biogeochemical evolution. Oxygen impacts sulfur cycling through the oxidation of sulfide minerals and the production of sulfate for microbial sulfate reduction (MSR). The isotopic signature of sulfur species preserved in the geologic record is affected by the prevailing biological and chemical processes and can therefore be used to constrain past oxygen and sulfate concentrations. Here, in a study of a late Archean analogue, we find that the sulfur isotopic signature in the water column of a seasonally stratified lake in southern China is influenced by MSR, whereas model results indicate that the isotopic signature of the underlying sediments can be best explained by concurrent sulfate reduction and sulfide oxidation. These data demonstrate that small apparent sulfur isotope fractionations (δ34Ssulfate-AVS = 4.2‰–1.5‰; AVS—acid volatile sulfides) can be caused by dynamic sulfur cycling at millimolar sulfate concentrations. This is in contrast to current interpretations of the isotopic record and indicates that small fractionations do not necessarily indicate very low sulfate or oxygen. |
| Databáze: | OpenAIRE |
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