UC San Diego

The globally-warm climate of the Early Eocene Climatic Optimum (EECO) offers a potential analog for a future greenhouse world. Studying the Eocene ocean gives us a window into an Earth where marine carbon cycling may have been much different from what is observed in the present. I use a long barite record in the Indian Ocean to contrast carbon export between higher temperatures in the EECO and hyperthermal events with the comparatively cooler Middle Eocene. Barite accumulation rate serves as a proxy for export production due to the microenvironments in which it forms. I find that reconstructed export production went from a normal baseline to a peak in the hotter Early Eocene, implying a highly productive open ocean. The low abundance of organic carbon in the sedimentary record suggests that the Eocene ocean had almost complete remineralization.