Thursday, 30 August 2007 - 1:30 PM
4.P1.D-1
Contributions to the Eocene climate record of the Antarctic Peninsula
Linda C. Ivany, Earth Sciences, Syracuse University, Heroy Geology Laboratory, Syracuse, NY 13244
Paleotemperatures derived from the δ18O values of bivalve shell from the La Meseta Formation on Seymour Island, Antarctic Peninsula, indicate ~10°C of cooling during the Eocene, much of which took place in two comparatively short intervals (~52 Ma and ~41 Ma). A short-term excursion to significantly more negative δ18O values appears to correlate with the middle Eocene climatic optimum of Bohaty and Zachos, and a rapid ensuing shift to much more positive values may reflect cooling associated with a proposed short-lived glacial advance. Late middle-late Eocene temperatures are universally cooler than lower in the section, but average values do not suggest freezing conditions. High-resolution records indicate a decrease in seasonality through the section, with significantly cooler summers in the late Eocene. Pebbly mudstone containing early Oligocene dinoflagellates immediately overlies La Meseta Formation sands, suggesting the potential for glacio-marine deposition at or near the Eocene-Oligocene boundary.