The Archean atmosphere

Catling, David C.; Zahnle, Kevin

doi:10.1126/sciadv.aax1420

Cited by 349 publications

(297 citation statements)

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“…There was a diversity of microbial mats and stromatolites 48,50 that actively precipitated carbonates 17 , with low-Mg calcite as the main mineral 50,59 . Although the solar luminosity during the lifetime of the Tumbiana lakes was likely 20% less than present 50,60,61 , in an atmosphere lacking ozone, the UV levels were expected to be significantly higher than present day sea level measurements 57,62,63 . These could have been comparable to the UV levels of the high altitude Andean lakes studied here.…”

Section: Discussionmentioning

confidence: 88%

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Modern arsenotrophic microbial mats provide an analogue for life in the anoxic Archean

Visscher

Gallagher

Bouton

et al. 2020

Commun Earth Environ

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The earliest evidence of life captured in lithified microbial mats (microbialites) predates the onset of oxygen production and yet, modern oxygenic mats are often studied as analogs based on their morphological similarity and their sedimentological and biogeochemical context. Despite their structural similarity to fossil microbialites, the presence of oxygen in most modern microbial mats disqualifies them as appropriate models for understanding early Earth conditions. Here we describe the geochemistry, element cycling and lithification potential of microbial mats that thrive under permanently anoxic conditions in arsenic laden, sulfidic waters feeding Laguna La Brava, a hypersaline lake in the Salar de Atacama of northern Chile. We propose that these anoxygenic, arsenosulfidic, phototrophic mats are a link to the Archean because of their distinctive metabolic adaptations to a reducing environment with extreme conditions of high UV, vast temperature fluctuations, and alkaline water inputs from combined meteoric and volcanic origin, reminiscent of early Earth.

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Section: Discussionmentioning

confidence: 88%

“…These could have been comparable to the UV levels of the high altitude Andean lakes studied here. Temperatures may have fluctuated between 0 and 40°C 63 . Most of these geochemical and physicochemical properties are shared by La Brava 41,42,[64][65][66][67][68][69] , and the microbial mats and microbialites it comprises.…”

Section: Discussionmentioning

confidence: 99%

Modern arsenotrophic microbial mats provide an analogue for life in the anoxic Archean

Visscher

Gallagher

Bouton

et al. 2020

Commun Earth Environ

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“…There is, however, a more apparent effect that has, to our perception, been underappreciated (Feulner, 2012) or even overlooked (Charnay et al, 2020;Catling and Zahnle, 2020) in the discussion of the faint-young-sun paradox: geothermal heating induced by the tidal deformation of the Earth by the newly formed Moon. In comparison to the other mechanisms detailed above, tidal heating always has a warming effect, whereas changes in the Earth's atmospheric composition, cloud coverage, land-to-surface fraction, albedo etc.…”

Section: Introductionmentioning

confidence: 99%

Habitability of the early Earth: Liquid water under a faint young Sun facilitated by strong tidal heating due to a nearby Moon

Heller¹,

Duda²,

Winkler³

et al. 2020

Preprint

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Geological evidence suggests liquid water near the Earth's surface as early as 4.4 gigayears ago when the faint young Sun only radiated about 70 % of its modern power output. At this point, the Earth should have been a global snowball. An extreme atmospheric greenhouse effect, an initially more massive Sun, release of heat acquired during the accretion process of protoplanetary material, and radioactivity of the early Earth material have been proposed as alternative reservoirs or traps for heat. For now, the faint-young-sun paradox persists as one of the most important unsolved problems in our understanding of the origin of life on Earth. Here we use astrophysical models to explore the possibility that the new-born Moon, which formed about 69 million years (Myr) after the ignition of the Sun, generated extreme tidal friction - and therefore heat - in the Hadean and possibly the Archean Earth. We show that the Earth-Moon system has lost about 3e31 J, (99 % of its initial mechanical energy budget) as tidal heat. Tidal heating of roughly 10 W/m^2 through the surface on a time scale of 100 Myr could have accounted for a temperature increase of up to 5 degrees Celsius on the early Earth. This heating effect alone does not solve the faint-young-sun paradox but it could have played a key role in combination with other effects. Future studies of the interplay of tidal heating, the evolution of the solar power output, and the atmospheric (greenhouse) effects on the early Earth could help in solving the faint-young-sun paradox.

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“…If the model ofZahnle et al (2019) is correct, the evolution of the isotopic composition of atmospheric Xe would thus be an indirect but powerful tracer of the evolution of the composition of the Earth's atmosphere. See alsoCatling & Zahnle (2020) for a review on the Archean atmosphere and on the potential meanings of the isotopic evolution of atmospheric xenon. The model ofZahnle et al (2019), through escape of Xe ions together with hydrogen ions, requires a source of hydrogen.…”

mentioning

confidence: 99%

“…These results are somewhat unexpected for a period of time when subduction and the possibility of N recycling to the mantle might not have been operative. The Archean atmospheric N "depletion" might have been the result of nitrogen sequestration in organic matter and in the crust at a time when environment reducing conditions did not permit fixed nitrogen to be returned to the atmosphere by denitrification and oxidative weathering (Stuëken et al 2016; Chapter 9).Combining estimates of the total atmospheric pressure with those of the PN2 suggests that there might have been some significant amount of other atmospheric species up to 0.7 bar when uncertainties are taken into account, which leaves space to have enough greenhouse gas like CO2 to counterbalance a low energy delivery by a fainter Sun at that time(Catling & Zahnle (2020) and refs. therein).…”

mentioning

confidence: 99%

Perspectives on Atmospheric Evolution from Noble Gas and Nitrogen Isotopes on Earth, Mars & Venus

Avice

Marty

2020

Space Sci Rev

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The composition of an atmosphere has integrated the geological history of the entire planetary body. However, the long-term evolutions of the atmospheres of the terrestrial planets are not well documented. For Earth, there were until recently only few direct records of atmosphere's composition in the distant past, and insights came mainly from geochemical or physical proxies and/or from atmospheric models pushed back in time. Here we review innovative approaches on new terrestrial samples that led to the determination of the elemental and isotopic compositions of key geochemical tracers, namely noble gases and nitrogen. Such approaches allowed one to investigate the atmosphere's evolution through geological period of time, and to set stringent constraints on the past atmospheric pressure and on the salinity of the Archean oceans. For Mars, we review the current state of knowledge obtained from analyses of Martian meteorites, and from the direct measurements of the composition of the present-day atmosphere by rovers and spacecrafts. Based on these measurements, we explore divergent models of the Martian and Terrestrial atmospheric evolutions. For Venus, only little is known, evidencing the critical need for dedicated missions.

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The Archean atmosphere

Cited by 349 publications

References 268 publications

Modern arsenotrophic microbial mats provide an analogue for life in the anoxic Archean

Modern arsenotrophic microbial mats provide an analogue for life in the anoxic Archean

Habitability of the early Earth: Liquid water under a faint young Sun facilitated by strong tidal heating due to a nearby Moon

Perspectives on Atmospheric Evolution from Noble Gas and Nitrogen Isotopes on Earth, Mars & Venus

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