The low O2 content of the Archean atmosphere implies that methane should have been present at levels ∼102 to 103 parts per million volume (ppmv) (compared with 1.7 ppmv today) given a plausible biogenic source. CH4 is favored as the greenhouse gas that countered the lower luminosity of the early Sun. But abundant CH4 implies that hydrogen escapes to space (↑space) orders of magnitude faster than today. Such reductant loss oxidizes the Earth. Photosynthesis splits water into O2 and H, and methanogenesis transfers the H into CH4. Hydrogen escape after CH4 photolysis, therefore, causes a net gain of oxygen [CO2 + 2H2O → CH4 + 2O2 → CO2 + O2 + 4H(↑space)]. Expected irreversible oxidation (∼1012 to 1013 moles oxygen per year) may help explain how Earth9s surface environment became irreversibly oxidized.

https://www.atmos.washington.edu/~davidc/papers_mine/Catling_etal_2001.pdf

Biogenic methane, hydrogen escape, and the irreversible oxidation of early Earth.

Earth's biogeochemical cycle of carbon delivers both limestones and organic materials to the crust. In numerous, biologically catalysed redox reactions, hydrogen, sulphur, iron, and oxygen serve pr...

/pdf/the-carbon-cycle-and-associated-redox-processes-through-time-1ik1x3er0h.pdf

The carbon cycle and associated redox processes through time

Factors affecting hazardous waste solidification/stabilization: a review.

6 – Hydration, Setting and Hardening of Portland Cement

Extreme 13Ccarb enrichment in ca. 2.0 Ga magnesite–stromatolite–dolomite–`red beds' association in a global context: a case for the world-wide signal enhanced by a local environment

Systematic decrease of high δ13C values with burial in late Archaean (2.8 Ga) diagenetic dolomite: evidence for methanogenesis from the Crixás Greenstone Belt, Brazil

Margaret L. Thomson

Papers

Systematic decrease of high δ13C values with burial in late Archaean (2.8 Ga) diagenetic dolomite: evidence for methanogenesis from the Crixás Greenstone Belt, Brazil

Anatomy of a porphyroblastic schist: Alkali-silica reactivity

Influence of cadmium on the hydration of C3A

Influence of CdO on the early hydration of 3CaO.Al2O3