Mass-Independent Sulfur Isotope Fractionation in the Photochemical SO2 Processes under the UV Radiation of Different Wave Length

• Published in: Geochemistry international Vol. 58; no. 11; pp. 1228 - 1238
• Main Authors: Velivetskaya, T. A., Ignatiev, A. V., Yakovenko, V. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.11.2020; Springer Nature B.V
• Subjects: Anomalies; Earth and Environmental Science; Earth Sciences; Experiments; Fractionation; Geochemistry; Incident radiation; Isotope fractionation; Isotopes; Lasers; Light sources; Low pressure; Mercury; Mercury lamps; Partial pressure; Photochemicals; Photochemistry; Photolysis; Spectra; Spectral composition; Sulfur; Sulfur dioxide; Sulfur isotopes; Sulphur; Sulphur dioxide; Ultraviolet radiation; Wavelengths; Xenon; Xenon lamps; sulfur isotopes; early Earth atmosphere; sulfur dioxide; mass-independent fractionation; photochemistry; Archean
• ISSN: 0016-7029; 1556-1968
• DOI: 10.1134/S0016702920110105

A series of photochemical experiments with sulfur dioxide were carried out using a xenon lamp (λ > 200 nm), a low-pressure mercury lamp (λ = 184.9 and 253.7 nm), and an UP-213 laser system (λ = 213 nm) as light sources. Based on the isotope data obtained for elemental sulfur (the end product of SO 2 photolysis), we revealed specifics in correlations between δ 34 S, ∆ 33 S, and ∆ 36 S values depending on the spectral characteristics of the incident radiation. Our studies showed that the Archean Δ 33 S/δ 34 S and Δ 36 S/Δ 33 S ratios could be reproduced in the SO 2 photolysis experiments by combining spectral composition of the radiation, the intensity of the spectral components, and the partial pressure of SO 2 . The results of the experiments suggest that the UV radiation with wavelengths less than 200 nm was a determining factor in the production of sulfur isotopic anomalies in the Archean atmosphere.