0000000000671014
AUTHOR
M.-n. Decraene
Tracking microbial signatures in stromatolites at micrometer scale with in situ iron isotopes. M-fed (Microbialites: formation, evolution, diagenesis)
International audience
Iron isotopes in micropyrites from the 2.7Ga Tumbiana Formation (Western Australia)
International audience; Stromatolites are considered to be the major drivers for the oceanic oxygenation during Archean time. However, respective rolesof photosynthetic and chemolithotroph organisms in these Archean rocks is not precisely demonstrated. Primarysub-micrometer pyrites associated with pristine organic matter are widespreadin Archean and modern sediments. Iron isotopes are fractionated by redox processesand biological activitiesand are widely used for tracing paleoredox conditions, diagenetic processes ormetabolic signaturesas iron respiration (DIR). Sub micrometer δ56Fevalues ofmicropyritesassociated with organic matter-laminae and CaCO3-SiO2matrixin stromatolites from the 2.7G…