Archean Oxygen In their intricate study, Catling et al. (1) attempted to explain the rise of atmospheric oxygen on the early Earth. The model they presented relies on a unique anaerobic ecosystem in which necessarily complex microbial fermentations interact closely with methanogens to decompose cyanobacteria and control the global preservation rate of organic carbon. The model begins schematica...

Pillow lava rims from the Mesoarchean Barberton Greenstone Belt in South Africa contain micrometer-scale mineralized tubes that provide evidence of submarine microbial activity during the early history of Earth. The tubes formed during microbial etching of glass along fractures, as seen in pillow lavas from recent oceanic crust. The margins of the tubes contain organic carbon, and many of the p...

Eleven taxa (including eight heretofore undescribed species) of cellularly preserved filamentous microbes, among the oldest fossils known, have been discovered in a bedded chert unit of the Early Archean Apex Basalt of northwestern Western Australia. This prokaryotic assemblage establishes that trichomic cyanobacterium-like microorganisms were extant and morphologically diverse at least as earl...

ARCHEAN CHERTS: CAN ELECTRON PARAMAGNETIC RESONANCE PROVIDE CLUES? A. Skrzypczak, L. Binet, D. Gourier, S. Derenne and F. Robert. Ecole Nationale Supérieure de Chimie de Paris, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05, France ([email protected], [email protected], [email protected], [email protected]), Museum National d'Histoire Naturelle, La...

1036 10 MARCH 2017 • VOL 355 ISSUE 6329 and Bachan developed a model of seawater chemistry and pH over time scales exceeding ~100 million years. Their highly robust probabilistic history of seawater pH and chemistry reflects evolving properties of Earth’s atmosphere, oceans, and crust. Seawater pH increased from early Archean values of ~6.5 to 7.0 to more recent values of ~7.5 to 9.0 mostly as ...

Abstract Many Archean cratons exhibit Paleoproterozoic rifted margins, implying they were pieces of some ancestral landmass(es). The idea that such an ancient continental assembly represents supercontinent has been proposed but remains to be justified. Starkly contrasting geological records between different clans have inspired alternative hypothesis where clustered in multiple, separate “super...

Abstract Constraining thickness and geothermal gradient of Archean continental crust are crucial to understanding geodynamic regimes the early Earth. crust-sourced tonalitic–trondhjemitic–granodioritic gneisses ideal lithologies for reconstructing thermal state crust. Integrating experimental results with petrochemical data from Eastern Block North China Craton allows us establish temporal–spat...