Selenium isotope evidence for pulsed flow of oxidative slab fluids
| Autor: | Besim Dragovic, Timm John, R. Schoenberg, T. Kurzawa, C. Rosca, S. Koenig, Varas-Reus, M., I |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Chemistry sulfides Flow (psychology) Inorganic chemistry chemistry.chemical_element Geology Oxidative phosphorylation recycling slab fluids 010502 geochemistry & geophysics 01 natural sciences Redox Sulfur selenium isotopes Isotopes of selenium 13. Climate action Geochemistry and Petrology sulfur redox Slab Environmental Chemistry subduction 0105 earth and related environmental sciences |
| Zdroj: | Geochemical Perspectives Letters |
| Popis: | Isotope systematics of the redox sensitive and chalcophile element selenium (Se) were investigated on exhumed parts of subducted oceanic lithosphere to provide new constraints on slab dehydration conditions during subduction. The samples c,, show increasing delta(82/76)Se(NIST3149 )with higher abundances of fluid mobile elements, comprising a larger range (-1.89 to +0.48 parts per thousand) than that of mantle (-0.13 +/- 0.12 parts per thousand) and altered ocean crust (-0.35 to -0.07 parts per thousand). Our data point to pronounced, local scale redox variations within the subducting crust, wherein oxidative fluids dissolve sulfides and mobilise oxidised Se species. Subsequently recrystallising sulfides preferentially incorporate isotopically lighter, reduced Se, which shifts evolving fluids and late stage sulfides to higher delta Se-82/76(NIST3149). Redistribution of Se by repeated cydes of sulfide reworking within the subducted crust can be reconciled with episodes of oxidised fluid pulses from underlying slab mantle in modem subduction zones. |
| Databáze: | OpenAIRE |
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