Past and Present Responses to Carbon Cycle Changes: Deducing Water-rock Reactions in Earth's Thin Skin

The School of Earth and Atmospheric Sciences Presents Dr. Evan Ramos, Brown University and Rice University

Past and Present Responses to Carbon Cycle Changes: Deducing Water-rock Reactions in Earth's Thin Skin

Earth’s climate state remains in a delicate balance. The inputs and outputs of carbon from the oceanatmosphere system set Earth’s climate, and any imbalance in these carbon fluxes can cause dramatic changes, leading to cascading impacts on surface environments and biota. During carbon cycle perturbations in the geologic past, often induced by rapid and large inputs of carbon to the atmosphere, chemical reactions between water, silicate minerals, and acids in the uppermost crust promote the removal of excess carbon from the atmosphere and enable climate to recover. 

Today, some of the leading solutions to thwarting anthropogenic climate change involve enhanced silicate weathering and soil remediation, owing to the role these reactions play in modulating climate. Yet, debate remains over the outstanding controls of these reactions (e.g., environmental, biologic, tectonic) and the geochemical tools we use to probe them. In this talk, I will cover two studies – one of a past climate change event and another set in the present – whose objectives are to uncover the mechanistic controls of silicate weathering using novel isotope measurements (i.e., Li isotopes) alongside traditional geochemical analyses. In doing so, these studies offer methodological and theoretical frameworks to gauge the responses of water-rock reactions to climate change, today and in the geologic past.