Fiche du document
Ce document est lié à :
info:eu-repo/semantics/altIdentifier/doi/10.7185/geochemlet.2209
Ce document est lié à :
info:eu-repo/semantics/altIdentifier/pissn/2410-339X
Ce document est lié à :
info:eu-repo/semantics/altIdentifier/pissn/2410-3403
Ce document est lié à :
info:eu-repo/grantAgreement/ERC//STROMATA 759289///
Ce document est lié à :
info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_E8EDFAFDCFAE3
info:eu-repo/semantics/openAccess , CC BY 4.0 , https://creativecommons.org/licenses/by/4.0/
Sujets proches
Sulphur Brimstone Bicycling Bicycle riding Bicycle transportationCiter ce document
J. Marin-Carbonne et al., « Early precipitated micropyrite in microbialites: A time capsule of microbial sulfur cycling », Serveur académique Lausannois, ID : 10.7185/geochemlet.2209
Métriques
Partage / Export
Résumé
Microbialites are organosedimentary rocks that have occurred throughout the Earth’s history. The relationships between diverse microbial metabolic activities and isotopic signatures in biominerals forming within these microbialites are key to understanding modern biogeochemical cycles, but also for accurate interpretation of the geologic record. Here, we performed detailed mineralogical investigations coupled with NanoSIMS (Nanoscale Secondary Ion Mass Spectrometry) analyses of pyrite S isotopes in mineralising microbial mats from two different environments, a hypersaline lagoon (Cayo Coco, Cuba) and a volcanic alkaline crater lake (Atexcac, Mexico). Both microbialite samples contain two distinct pyrite morphologies: framboids and euhedral micropyrites, which display distinct ranges of δ34S values1. Considering the sulfate-sulfur isotopic compositions associated with both environments, micropyrites display a remarkably narrow range of Δpyr (i.e. Δpyr ≡ δ34SSO4 − δ34Spyr) between 56 and 62‰. These measured Δpyr values agree with sulfate-sulfide equilibrium fractionation, as observed in natural settings characterised by low microbial sulfate reduction respiration rates. Moreover, the distribution of S isotope compositions recorded in the studied micropyrites suggests that sulfide oxidation also occurred at the microbialite scale. These results highlight the potential of micropyrites to capture signatures of microbial sulfur cycling and show that S isotope composition in pyrites record primarily the local micro-environments induced by the microbialite.