Emma Hartke

The objective of my project is to evaluate how changes in the global carbon cycle are preserved in the rock record by evaluating high-resolution differences between the organic carbon and carbonate carbon isotopic record during an ancient global change event in earth history. Whereas both isotopic records (organic carbon and carbonate carbon) draw from the ocean-atmosphere CO2 reservoir, variations in the magnitude and timing between these two records can help to evaluate potential causes of global carbon cycle perturbations.

My project, under the direction of Dr. Bradley Cramer at the University of Iowa, focuses on organic carbon isotope chemostratigraphy of a major biogeochemical event from the Silurian Period (~430 Ma) known as the Ireviken Event. The Ireviken Event, the first of three extinction events during the Silurian, demonstrates a small “spike” in the carbon isotope record that began during this extinction event. The specific objectives of this study are to evaluate precisely the relative timing of this extinction event with respect to changes in the global carbon cycle, as well as the synchronicity of the organic and carbonate signals in order to determine potential cause-effect relationships within the ocean-atmosphere-biosphere earth system.