Dartmouth Events

Earth Science Seminar - Dr. Benjamin Uveges, MIT

Event, Episodes or Endurance? Refining the Geochemical Record of Atmospheric Oxygenation. Seminar is 1:10pm to 2:10 pm

Thursday, January 26, 2023
1:00pm – 2:15pm
Wilder 104
Intended Audience(s): Alumni, Faculty, Postdoc, Staff, Students-Graduate, Students-Undergraduate
Categories: Arts and Sciences, Lectures & Seminars

Understanding the timing and trajectory of atmospheric oxygenation remains fundamental to deciphering its causes and consequences. Given its origin in oxygen-free photochemistry, mass-independent sulfur isotope fractionation (S-MIF) is widely accepted as a geochemical fingerprint of an anoxic atmosphere. However, although it is generally agreed that oxygen began to accumulate within the atmosphere between 2.5–2.3 Ga, different readings of the S-MIF record have been used to portray dramatically different oxygenation trajectories—with some workers arguing for a unidirectional geologically rapid rise in O2, while others envisage an oscillatory trajectory whereby pO2 repeatedly crossed the threshold necessary to resume S-MIF genesis. Here, we take a deeper look at the S-MIF record in an attempt to reconcile these conflicting narratives. Our statistical and modeling analyses, as well as new sulfur isotope data, implicate an intermediate, and potentially uniquely feedback-sensitive, Earth system state in the wake of the Great Oxidation Event, rather than a sweeping step-function(s) between bi-stable endmembers.

Visit our seminar webpage.

For more information, contact:
Marisa Palucis

Events are free and open to the public unless otherwise noted.