Unit Affiliation: Geochemistry, Lamont-Doherty Earth Observatory (LDEO)
Understanding the mechanisms controlling atmospheric CO2 is increasingly vital in a warming world, particularly for developing accurate projections of future climate change scenarios. This proposed research focuses on the Eocene-Oligocene Transition (EOT), which marks one of the most dramatic climate transitions of the Cenozoic era. At the E-O boundary (~34 million years ago), climate shifted from “greenhouse” to “icehouse” conditions. Earth cooled by approximately 3.5°C, and continent-wide glaciation began on Antarctica. Atmospheric CO2 decreased1 and North Atlantic Overturning Circulation was initiated2, henceforth contributing to global heat distribution. The temperature change during the EOT is opposite in sign but similar in scale to anticipated warming over this century, providing an important opportunity to study the natural processes and tipping points that drive climate and atmospheric CO2 changes. While the atmospheric CO2 decrease has already been documented for the EOT, the mechanisms of CO2 sequestration remain unclear. This study addresses this gap by reconstructing changes in Eocene-Oligocene carbon and nutrient storage and weathering, using benthic foraminiferal trace element and stable isotope proxies. The study will focus on the deep Pacific, the largest ocean basin and carbon reservoir at that time.