Chem Seminar 10/11/24

Friday, October 11, 12:30 PM to 01:20 PM PDT

Location: MSB 123

Speaker: Lizzy Trower

Affiliation: CU Boulder

Title: A 500-million-year record of seawater carbonate chemistry

Abstract: Seawater carbonate chemistry links Earth's climate and carbon cycle through the production and preservation of carbonate sediments. Models and carbonate facies abundance records have generated hypotheses about trajectories of seawater carbonate chemistry, including responses to key events in the evolutionary history of carbonate biomineralizers. However, tests of these hypotheses have remained elusive. In this talk, I will describe my work developing and applying a new proxy for the calcium carbonate saturation state of ancient seawater based on the sizes of ooids, a type of calcium carbonate sand grain that forms in shallow marine environments. I will share the experiments and groundtruthing in modern field sites I used to test this tool. Then, I will show an application of this new proxy to a suite of samples spanning Phanerozoic time (the past ~530 million years) and compare this new record of seawater carbonate chemistry with previous ideas about how seawater chemistry influenced key events in the evolutionary history of carbonate biomineralizing organisms, and vice versa.