Noah Planavsky, Olivier Rouxel, Andrey Bekker, Russell Shapiro, Phil Fralick, Andrew Knudsen

2009/8/30

Earth and Planetary Science Letters

286

1

230-242

Elsevier

We conducted a geochemical and petrographic study of the 1.89 billion year old Gunflint
and Biwabik iron formations, with the goal of determining the importance of microbial iron-
oxidation in the formation of iron-and microfossil-rich stromatolites. We used redox-sensitive
tracers, such as iron isotopes and rare earth elements, to decipher whether these ancient
microbial ecosystems harbored cyanobacteria or Fe-oxidizing bacteria as primary
producers. Iron-rich stromatolites contain non-significant or positive Ce anomalies, which ...