Isotope and Redox Geochemistry of Sulfur in Earth System Processes: Insights into Organic-Inorganic Sulfur Formation and Cycling in Modern, Ancient and Prebiotic Environments

UK Centre for Astrobiology in collaboration with Earth and Planetary Science seminar series

Earth system processes related to biogeochemical sources, sinks, and transformation pathways of organic‐inorganic sulfur in modern, atmospheric and primitive mantle systems, and their preservation into ancient environments, is perhaps the most widely cited line of evidence responsible for sulfur mass independent (S-MIF) to mass dependant fractionation (S-MDF).

In this seminar, I will focus on the use multiple isotope of sulfur (³²S, ³³S, ³⁴S, and ³⁶S) measurements of different sulfur (δ³⁴S and Δ³³S (or Δ³⁶S)) species together with other instrumental techniques to characterise quantitatively the origin, redox chemistry and metabolic transformation of sulfur species in different environmental and experimental systems. I will extend these database of sulfur isotope and redox geochemistry to explore the magnitude and signs of Δ³⁶S/Δ³³S and δ³⁴S produced during; (1) sulfur cycling in natural systems with a focus on disentangling and identifying different microbial and abiological pathways for sulfur transformations; (2) sulfate reduction metabolism, its architecture, and its function in both photochemical and thermochemical processes; (3) studies of early earth environments with the goal of understanding the role of biology in the context of a system dominated by atmospheric isotope signatures; and (4) studies of organic sulfur compounds in petroleum, and more recently in prebiotic and primitive solar system materials. The emerging mechanisms responsible for these isotope signatures and their implications will be discussed in more detail. Ultimately this work offers a framework where these signals can be used as a diagnostic marker to distinguish between above listed processes that occur in present and past geologic environments.

UK Centre for Astrobiology seminar series

The astrobiology seminar series is run by the UK Centre for Astrobiology, based in the School of Physics & Astronomy. Astrobiology is a multi-disciplinary subject and the seminar series actively encourages attendance by undergraduates, postgraduates and academic staff from other departments.

For further information or proposals for speakers contact:
Mark Fox-Powell (m.fox-powell [at] ed.ac.uk) or Jesse Harrison (j.p.harrison [at] ed.ac.uk)

https://www.astrobiology.ac.uk/events/

Coffee will be served following the seminar.