Ross Sea West Antarctic Ice Sheet History in the Late Cenozoic

International Ocean Discovery Program (IODP) Expedition 374 collected a latitudinal and depth transect of five drill sites from the outer continental shelf and rise in the eastern Ross Sea in January to March 2018. The expedition aimed to resolve the relationship between climatic/oceanic change and West Antarctic Ice Sheet (WAIS) evolution over the past 20 million years. This location was selected because numerical ice sheet models indicate that it is highly sensitive to changes in ocean heat flux and sea level. The drilling was designed for optimal data-model integration, which will enable an improved understanding of the sensitivity of Antarctic Ice Sheet mass balance during warmer-than-present climates (e.g., the early Pliocene and middle Miocene). The objectives were to 1) Evaluate the contribution of West Antarctica to far-field ice volume and sea level estimates; 2) Reconstruct ice-proximal atmospheric and oceanic temperatures to identify past polar amplification and assess its forcings/feedbacks; 3) Assess the role of oceanic forcing (e.g., sea level and temperature) on Antarctic Ice Sheet stability/instability; 4) Identify the sensitivity of the AIS to Earth’s orbital configuration under a variety of climate boundary conditions; 5) Reconstruct eastern Ross Sea bathymetry to examine relationships between seafloor geometry, ice sheet stability/instability, and global climate. This talk will present the initial scientific results that resulted from this expedition, with a focus on the paleoenvironmental reconstructions that were obtained from the sedimentolgical, geochemical and paleotonlogical datasets.