Evidence for microbial life in synsedimentary cavities from 2.75 Ga terrestrial environments
MetadataShow full item record
Fluviolacustrine sediments of the 2.75 Ga Hardey Formation (Fortescue Group, Australia) preserve pendant columnar structures with stromatolitic lamination within synsedimentary cavities. The millimeter-sized, finger-like columns strongly resemble microbialites from modern basaltic caves and indicate the likely presence of microbial biofi lms. The ancient microbial columns are preserved by chert and locally occur as reworked clasts, indicating a near-depositional age for the structures. Sulfur isotopic analysis of pyrite in the columns and adjacent carbonaceous matrix yields d34SCDT (CDT?Canyon Diablo troilite) values between -8.5? and +19?, showing signifi cant fractionation characteristic of biological cycling of sulfur. Organic matter in cavity ceilings and shale matrix has d13CPDB (PDB?Peedee belemnite) values between -55? and -43?, suggesting the presence of methanotrophs. Our results suggest that 2.75 Ga terrestrial environments supported a microbial ecosystem, including microbes that inhabited synsedimentary hollows, extending the fossil record of coelobionts by ~1.5 b.y. Subsurface cavities represent a new habitable microenvironment for early life on Earth, and an analogue for ancient life on Mars.
Showing items related by title, author, creator and subject.
Naeher, Sebastian; Niemann, H.; Peterse, F.; Smittenberg, R.; Zigah, P.; Schubert, C. (2014)We analysed the distributions of glycerol dialkyl glycerol tetraethers (GDGTs) and other lipid biomarkers [glycerol dialkyl diethers (DGDs), fatty acids (FAs), sterols, hopanoids and phytol] in the water column and sediments ...
Tube fossils from gossanites of the Urals VHMS deposits, Russia: Authigenic mineral assemblages and trace element distributionsAyupova, N.; Maslennikov, V.; Tessalina, Svetlana; Shilovsky, O.; Sadykov, S.; Hollis, S.; Danyushevsky, L.; Safina, N.; Statsenko, E. (2015)© 2016.The occurrence, types, morphology, and mineralogical characteristics of tube microfossils were studied in gossanites from twelve VHMS deposits of the Urals. Several types of tube microfossils were recognized, ...
Busigny, V.; Lebeau, O.; Ader, M.; Krapez, Bryan; Bekker, A. (2013)The Hamersley Group comprises a Late Archean sedimentary succession, which is thought to record the prelude to the atmospheric oxygenation in the Paleoproterozoic, the so-called Great Oxidation Event (GOE), at ~2.4 Ga. ...