Atmosphere early composition

Current results of this exercise, using the Xe component compositions listed in Table 1, are reviewed in Pepin (2000). Applied to Earth, a modeling procedure involving derivation of fractionation relationships between nonradiogenic terrestrial and meteoritic Xe compositions simultaneously identifies a composition named U-Xe as primordial Xe, and establishes the presence of an atmospheric Xe component due principally to fission of extinct as noted earlier in this chapter. Hydrodynamic escape of U-Xe leaves its fractionated residue on Earth. Evolution of atmospheric Xe from this early composition to its present isotopic state by subsequent degassing of fission and radiogenic... 

Rubey, W. W. (1955). Development of the hydrosphere and atmosphere, with special reference to probable composition of the early atmosphere. In "Crust of the Earth" (A. Poldenvaart, ed.), pp. 631-650. Geological Society of America, New York. 

The chemical composition of the Earth s interior determined the character (the oxidation state) of the primeval atmosphere. If metallic iron had collected in the Earth s core in the early phase of the accretion, the exhalations from the interior of the Earth would have consisted mainly of CO2 and H20, since the gas from the interior could only have come into contact with FeO and Fe203 silicates in the mantle. If, however, metallic iron had been distributed throughout the mantle, the iron and the FeO silicates would have had a reductive influence on the gases the gas exhaled into the atmosphere would then have consisted of CH4, H2 and NH3 (Whittet, 1997). 

The period of emergence of life on Earth is constrained to be between the period 4.0-3.7 Gyr ago, for which there is no fossil record. Urey postulated that all of the planets formed from the same solar nebula and so the early Earth should have an atmosphere with a composition the same as that of Jupiter (known at the time),... 

Hydrogen isotopic compositions, expressed as molar D/H ratios, of solar system bodies. The relatively low D/H values in the atmospheres of Jupiter and Saturn are similar to those in the early Sun, whereas D/H ratios for Uranus and Neptune are intermediate between the Jupiter-Saturn values and those of comets and chondrites. The Earth s oceans have D/H shown by the horizontal line. Mars values are from SNC meteorites. Modified from Righter et al. (2006) and Lunine (2004). 

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