Emily Garcia

Carbon Associated Sulfate

              The history of life on Earth is an important question in the Earth Sciences. The Great Ordovician Biodiversification Event was an interval of twenty five million years during which marine life flourished significantly. This drastic change in biodiversity could have occurred for various reasons including changes in environmental conditions, geography and adaptive strategies of fauna. This study will focus on the environmental changes during the Ordovician, which may have allowed for the biodiversification to occur.

Over the course of the summer I will be assisting Professor Pedro Marenco by conducting a series of Carbonate Associated Sulfate (CAS) extractions in the geochemistry lab at Bryn Mawr College. CAS serves as a proxy to examine sulfur isotope concentrations in sediments deposited in marine rocks. The goal of these extractions and this examination is to help determine whether the oceans, in which the formations were deposited were anoxic, as has been suggested. This observation can help identify the ways in which the oceans behaved during the Ordovician. Prior to CAS extraction, our research group will spend ten days collecting rock samples from Millard County, Utah. These samples, as well as samples already studied, will allow us to make further interpretations to whether there was a lack of oxygen in the deep ocean and what kind of a role that played in causing or hindering biodiversification during the Ordovician.