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Cited by 298Origins and Evolution of LifePaleontology and Stratigraphy of FossilsAstro and Planetary Science

Earth's Earliest Atmospheres

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Zahnle, K., Schaefer, L., Fegley, B.·2010·Cold Spring Harbor Perspectives in Biology
DOI 10.1101/cshperspect.a004895PMC PMC2944365
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Abstract

Earth is the one known example of an inhabited planet and to current knowledge the likeliest site of the one known origin of life. Here we discuss the origin of Earth's atmosphere and ocean and some of the environmental conditions of the early Earth as they may relate to the origin of life. A key punctuating event in the narrative is the Moon-forming impact, partly because it made Earth for a short time absolutely uninhabitable, and partly because it sets the boundary conditions for Earth's subsequent evolution. If life began on Earth, as opposed to having migrated here, it would have done so after the Moon-forming impact. What took place before the Moon formed determined the bulk properties of the Earth and probably determined the overall compositions and sizes of its atmospheres and oceans. What took place afterward animated these materials. One interesting consequence of the Moon-forming impact is that the mantle is devolatized, so that the volatiles subsequently fell out in a kind of condensation sequence. This ensures that the volatiles were concentrated toward the surface so that, for example, the oceans were likely salty from the start. We also point out that an atmosphere generated by impact degassing would tend to have a composition reflective of the impacting bodies (rather than the mantle), and these are almost without exception strongly reducing and volatile-rich. A consequence is that, although CO- or methane-rich atmospheres are not necessarily stable as steady states, they are quite likely to have existed as long-lived transients, many times. With CO comes abundant chemical energy in a metastable package, and with methane comes hydrogen cyanide and ammonia as important albeit less abundant gases.

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Crossref · 10.1101/cshperspect.a004895

Cites

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  • There is much evidence that H2O and biogenic CH4 were most likely also present around 2.6-2.8 Ga.

    “Besides the main atmospheric species CO 2 and N 2 there is much evidence that H 2 O and biogenic CH 4 were most likely also present around 2.6 - 2.8 Ga (Hinrichs 2002; Zahnle et al. 2010; Zerkle et al. 2012; Lammer et al. 2018).”

    From The young Sun's XUV-activity as a constraint for lower CO2-limits in the Earth's Archean atmosphere (2021) · cites this paper as Zahnle et al. 2010

    The Impact Degassing section discusses H₂O and CH₄ in models of Earth's early atmosphere, and After the Moon-forming Impact considers possible methane sources. These passages do not establish evidence for specifically biogenic methane at 2.6–2.8 Ga; the methane sources discussed there are hydrothermal processes and impacts. Page numbers are unavailable in our copy. (LLM, conf=0.83)

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  • The Hadean atmosphere was more neutral rather than completely reducing.

    “Geochemical and isotopic evidence suggests that the atmosphere of the post-Moon forming impact Earth was more neutral rather than completely reducing (Holland 1984;Sleep 2010;Zahnle et al. 2010).”

    From The Emergence of Life (2019) · cites this paper as Zahnle et al. 2010

    In “The Moon-forming Impact” (page unavailable), the paper says a strongly reducing, methane-dominated atmosphere after the mantle solidified was unlikely and estimates a CO₂-rich atmosphere instead. But it also says the earlier post-impact atmosphere likely remained reduced, with H₂ and CO prominent. The claim omits that time distinction; the paper does not present isotopic evidence as direct evidence of atmospheric redox state. (LLM, conf=0.84)

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  • Earth's early atmosphere formed via volcanic degassing, providing N2, CO2, and water, with small quantities of H2, CO, and CH4, and negligible amounts of O2.

    “In particular, Earth's early atmosphere formed via volcanic degassing (see Section 3.2.2), which would have provided N2, CO2, and water, with small quantities of H2, CO, and CH4, and negligible amounts of O2 (Zahnle et al., 2010).”

    From The Astrobiology Primer v2.0 (2016) · cites this paper as Zahnle et al., 2010

    The Volcanic Atmospheres section (page unavailable) describes a proposed atmosphere derived from volcanic gases, mostly H2O, CO2, and N2, with small amounts of CO and H2. But the Abstract (page unavailable) says that this composition would contain essentially no CH4, rather than listing CH4 among the gases supplied in small quantities. The paper also discusses impact degassing as an alternative to volcanic outgassing, so it does not establish volcanic degassing as the sole origin of Earth's early atmosphere. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • The current consensus is that the early atmosphere as a stable steady state most likely would have been largely neutral, comprised primarily of CO2 and N2, although more reducing atmospheres could have existed transiently.

    “The current consensus, however, is that the early atmosphere as a stable steady state most likely would have been largely neutral, comprised primarily of CO2 and N2, although more reducing atmospheres could have existed transiently [59,60].”

    From Prebiotic Reaction Networks in Water (2020) · cites this paper as [60]

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Cites

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6 of the 148 references couldn’t be matched to a known paper.

Research works printed but not linked: 4

  1. [9]9. Arrhenius G, De BR, Alfve ´n H. 1974. Origin of the ocean. In The Sea, Vol. 5: E.D. Goldberg (Ed.) Wiley-Interscience, New York, pp. 839-861.
  2. [39]39. Holland HD. 1962. Model for the evolution of the earths atmosphere. In Petrologic studies: a volume in honor of A.G. Buddington, E.J. Engle, H.L. James, B.F. Leonard (eds.). Geological Society of America, Boulder, pp 447 -477.
  3. [45]45. Kasting JF. 1982. J Geophys Res 87: Pages 3091-3098.
  4. [81]81. Schaefer L, Fegley B. 2009. Chemistry of Silicate Atmos- pheres of Evaporating Super-Earths Submitted to Astrophys. J Lett [in press].

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Authors
Zahnle, K., Schaefer, L., & Fegley, B.
Affiliations
  • Ames Research Center (US)
  • Washington University in St. Louis (US)
Corresponding author
Zahnle, K.
ORCID
Venue
Cold Spring Harbor Perspectives in Biology
Publisher
Cold Spring Harbor Laboratory
Published
2010-06-23
Volume
2
Issue
10
Pages
a004895-a004895
ISSN
1943-0264 (ISSN-L)
DOI
10.1101/cshperspect.a004895
PMC
PMC2944365
OpenAlex
W2144682212
Cited by
298
References
148
Citations by year
2026: 19 · 2025: 21 · 2024: 17 · 2023: 23 · 2022: 28 · 2021: 25 · 2020: 26 · 2019: 21 · 2018: 25 · 2017: 9 · 2016: 15 · 2015: 15 · 2014: 10 · 2013: 21 · 2012: 7
Type
posted content
Language
en
Open access
Locations
  • Cold Spring Harbor Perspectives in Biology (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
National Aeronautics and Space Administration
Topics
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Origins and Evolution of Life
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Stratigraphy of Fossils
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Astro and Planetary Science
Keywords
early Earth atmosphere, origin of life, Moon-forming impact, reducing atmosphere, methane, carbon monoxide, hydrogen cyanide, ammonia, volatile condensation
MeSH terms
Origin of Life, Atmosphere, Moon, Earth, Planet

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