Glaciations and carbon isotope excursions across Earth history: Insights from the Re-Os system

The Ediacaran to late Cambrian (ca. 635-500 Ma) began with the termination of the last of the Snowball Earth glaciations and witnessed numerous biological innovations and large-scale perturbations to global biogeochemical cycles, all set against the backdrop of the break-up of the Rodinia supercontinent. Advances in our understanding of these phenomena require new radiometric ages coupled with paleontological, geochemical, and field-mapping efforts. Determining the timing of onset and duration of large-scale perturbations to biogeochemical cycles during the Ediacaran and Cambrian periods remains a challenge for elucidating their driving mechanisms and possible connections to biological innovations and extinctions. Here, I present new Re-Os ages and Os and Nd isotope stratigraphy from globally-distributed sedimentary successions that span the interval 635-500 Ma. These new age constraints and geochemical datasets help refine the temporal framework of the late Neoproterozoic and Cambrian and provide insights into the role of changing continental weathering fluxes during these critical intervals of Earth history.

Dr. Alan Rooney is an assistant professor in the Department of Earth and Planetary Sciences at Yale University. Prior to Yale, Rooney completed a postdoctoral fellowship at Harvard after earning his Ph.D. from Durham University. Before his Ph.D., Rooney completed a Masters at Stockholm University after an undergraduate degree at Glasgow University. He is interested in understanding the interactions between tectonics, climatic processes, and geochemical cycles on a range of time scales. To this end, he employs radiogenic isotope geochemistry, in particular, the rhenium-osmium (Re-Os) geochronometer, Sr and Nd isotopes combined with field-based mapping, sedimentology, stratigraphy, and mineralogy to interrogate the rock record of critical transitions in Earth history.

For the zoom information, please contact Rey Garduño (rgarduno@stanford.edu)