Paleogeology

Paleogeology, Paleoclimate, in relation to Evolution of Life on Earth

Prebiotic atmosphere

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 and volcanic outgassing could have maintained a hydrogen mixing ratio of more than 30%. The production of prebiotic organic compounds in such an atmosphere would have been more efficient than either exogenous delivery or synthesis in hydrothermal systems. The organic soup in the oceans and ponds on early Earth would have been a more favorable place for the origin of life than previously thought.
Tian F, Toon OB, Pavlov AA, De Sterck H. A hydrogen-rich early Earth atmosphere. Science. 2005 May 13;308(5724):1014-7. Epub 2005 Apr 7
Comment in: Science. 2005 May 13;308(5724):962-3. Science. 2006 Jan 6;311(5757):38; author reply 38.

Comment on "A hydrogen-rich early Earth atmosphere". [Science. 2006] PMID: 16400134
Atmospheric science. Rethinking Earth's early atmosphere. [Science. 2005] PMID: 15890865
Impact melting of frozen oceans on the early Earth: implications for the origin of life. [Proc Natl Acad Sci U S A. 1994] PMID: 11539550
Bolide impacts and the oxidation state of carbon in the Earth's early atmosphere. [Orig Life Evol Biosph. 1992] PMID: 11537523
The evolution of the prebiotic atmosphere. [Orig Life. 1984] PMID: 11536587 See all Related Articles...

The evolution of the prebiotic atmosphere : SpringerLink - Article: "High CO2 levels are required to warm the primitive earth in the face of decreased solar luminosity. The atmosphere should have had an effective stratospheric cold trap, which would have limited the abiotic production rate of oxygen to relatively low values. Photostimulated oxidation of ferrous iron in the oceans should have been the dominant source of atmospheric H2. Rainout of H2O2 would have kept the atmospheric H2 content high and the O2 content low, even if other sources of H2 were small." Article PubMed ChemPort James F. Kasting: The evolution of the prebiotic atmosphere Kasting, J. E. Origins of Life 14, 75−82 (1984).

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