Researchers have provided new insight into one sulfur polymerization process that could have been important in the anoxic atmosphere of the Archean Earth. The study could also be relevant to understanding mass-independent fractionation of sulfur isotopes in general. Using theoretical and computational studies, scientists examined the mechanism by which energy is transferred when two sulfur atoms combine into a diatomic molecule (S2). In doing so, they have shed new light on factors that contribute to the recombination process, and how this process might effects isotopes of sulfur found in the geological record.

Astrobiologists are still unsure of the exact composition of ancient Earth’s atmosphere more than 2.3 billion years ago. Determining what the Archean atmosphere was like, and the processes that shaped it, is important because life is thought to have originated on our planet during this time.

The study, “One possible source of mass-independent fractionation of sulfur isotopes in the Archean atmosphere of Earth,” was published in the journal Geochimica et Cosmochimica Acta. The work was supported by NASA Astrobiology through the Exobiology & Evolutionary Biology Program.