The Eocene to Oligocene climate transition was the most profound oceanographic and climatic change of the past 50 million years. In this project, research will be conducted to examine this global transition from a warm "greenhouse" planet to a cool "icehouse" planet, between ~40-24 myrs ago, as well as to investigate the effects of global ice-sheet growth and subsequent glacial variations on global climate. Stable carbon and oxygen isotopic and trace element (Mg/Ca) geochemical data will be collected from carefully collected, pristine, planktonic and benthic foraminifera from five low-latitude Atlantic industry/survey cores and four ODP/DSDP sites to reconstruct sea-surface temperatures, deepwater temperatures, and ice-volume changes. Questions to be addressed include: 1) Was significant deep-water cooling associated with an increase in continental glaciation during the Eocene-Oligocene transition? 2) Was late Eocene through Oligocene SSTs higher than today and was the climate transition associated with minimal cooling of the tropics, thereby producing a larger increase in the early Oligocene latitudinal SST gradient than previously inferred? 3) Did brief (<1 myr) glaciations occur in the middle to late Eocene prior to E-O transition? These new data will provide insight into the mechanisms of transient climate change and the greenhouse-icehouse transition, as well as providing more robust information for climate models attempting to reconstruct Earth History climatic shifts. The proposed research will involve undergraduate and high school students and support two recent female Ph.D.'s. The PI's are involved with public outreach via the Geology Museum and K-12 teacher training.
