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Mass-independent fractionation of sulfur isotopes in Archean sediments: strong evidence for an anoxic Archean atmosphere.
Mass-independent fractionation (MIF) of sulfur isotopes has been reported in sediments of Archean and Early Proterozoic Age (> 2.3 Ga) but not in younger rocks. The only fractionation mechanism thatExpand
Greenhouse warming by CH4 in the atmosphere of early Earth.
Earth appears to have been warm during its early history despite the faintness of the young Sun. Greenhouse warming by gaseous CO2 and H2O by itself is in conflict with constraints on atmospheric CO2Expand
New insights into Archean sulfur cycle from mass-independent sulfur isotope records from the Hamersley Basin, Australia
We have measured multiple sulfur isotope ratios ( 34 S/ 33 S/ 32 S) for sulfide sulfur in shale and carbonate lithofacies from the Hamersley Basin, Western Australia. The v 33 S values (v 33 SWN 33Expand
A Hydrogen-Rich Early Earth Atmosphere
We show that the escape of hydrogen from early Earth's atmosphere likely occurred at rates slower by two orders of magnitude than previously thought. The balance between slow hydrogen escape andExpand
UV shielding of NH3 and O2 by organic hazes in the Archean atmosphere
The late Archean atmosphere was probably rich in biologically generated CH4 and may well have contained a hydrocarbon haze layer similar to that observed today on Saturn's moon, Titan. Here weExpand
Influence of carbon dioxide clouds on early martian climate.
Recent studies have shown that clouds made of carbon dioxide ice may have warmed the surface of early Mars by reflecting not only incoming solar radiation but upwelling IR radiation as well. However,Expand
TRANSONIC HYDRODYNAMIC ESCAPE OF HYDROGEN FROM EXTRASOLAR PLANETARY ATMOSPHERES
Hydrodynamic escape is an important process in the formation and evolution of planetary atmospheres. Transonic steady state solutions of the time-independent hydrodynamic equations are difficult toExpand
Organic haze on Titan and the early Earth
Recent exploration by the Cassini/Huygens mission has stimulated a great deal of interest in Saturn's moon, Titan. One of Titan's most captivating features is the thick organic haze layer surroundingExpand
Massive release of hydrogen sulfide to the surface ocean and atmosphere during intervals of oceanic anoxia
Simple calculations show that if deep-water H2S concentrations increased beyond a critical threshold during oceanic anoxic intervals of Earth history, the chemocline separating sulfidic deep watersExpand
A Coupled Ecosystem-Climate Model for Predicting the Methane Concentration in the Archean Atmosphere
A simple coupled ecosystem-climate model is described that canpredict levels of atmospheric CH4, CO2, and H2during the Late Archean, given observed constraints on Earth'ssurface temperature. We findExpand
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