The selenium isotope perspective on marine and atmospheric redox perturbations
From University of St Andrews, UK
Selenium isotopes are a newly emerging tool for reconstructing biogeochemical events in deep time. The six stable isotopes are fractionated primarily during the reduction of selenium oxyanions under suboxic conditions, and the oxyanions in turn require free O2 to be stable in surface environments. These properties make selenium an ideal proxy for regional-scale redox perturbations over Earth’s history.
In this talk, I will present new insights gained from applications of this proxy to the Permian-Triassic mass extinction event, the Neoproterozoic oxygenation of the deep ocean, and pulses of oxygen in the Neoarchean atmosphere. Collectively, these data reveal strengths and weaknesses of the selenium isotope tool and lay the foundation for future studies.