A Robust Temporal Framework for the Paleoproterozoic Crash of Atmospheric Oxygen

The protracted rise of atmospheric oxygen has important implications for the trajectory of biological evolution and global nutrient cycling. This work will test ties between large-scale environmental changes and biotic macroevolution in the Paleoproterozoic. Investigators will obtain age constraints for sediments within the Onega Basin of Russia and the Lastoursville Basin of Gabon to evaluate the synchroneity of carbon burial episodes potentially associated with an overshoot and crash of atmospheric oxygen levels in the Paleoproterozoic era.

The geochemical constraints they obtain will allow to critically evaluate the synchronicity and extent of marine conditions and oxygen levels at the termination of what may have been the most dramatic disturbance to the carbon cycle in Earth history. These efforts will be paired with a science video-logging series, Terralingua: Reading the Rock Record, which will be broadly disseminated through the TravelingGeologist platform on social media, reaching a total audience of over one million globally.

This series will provide content highlighting the variety of tasks that geoscientists complete, including field work in Russia with a team of international collaborators, geochemistry laboratory and mass spectrometry work, and will also cover common barriers to entry in the geosciences and academia.

The goal of this project is to improve our understanding of the trajectory of atmospheric oxygen during the ~2.3-2.0 Ga Lomagundi-Jatuli (LJ) positive carbon isotope excursion and the subsequent Shunga negative carbon isotope excursion in the Onega Basin of Russia and the Lastoursville Basin of Gabon. The proposed research will address: 1) How did oxidative weathering vary during these carbon isotope excursions? 2) Do the end-LJ and the Shunga Event occur synchronously in the Onega and Lastoursville Basins?

The petrologic, isotopic and temporal constraints to be determined will permit global correlations and shed novel insights into the rise of oxidative weathering and global carbon cycling at this critical juncture. This will support education, outreach, and diversity initiatives through the training of a PhD student and postdoc and the production of a broadly disseminated videologging series (Terralingua: Reading the Rock Record) focused on geochemistry as well as promoting inclusivity in field- and laboratory-based geoscience fields and more broadly within academia.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.