West Antarctic paleotopography estimated at the Eocene‐Oligocene climate transition

Abstract

One generally recognized limitation of models for rapid growth of Antarctic ice near the Eocene‐Oligocene transition is that they are based on present topography, corrected only for removal of modern ice. For West Antarctica, this results in large areas below sea level that would not readily host ice. In the recently active West Antarctic rift system, other factors may have contributed to significant vertical motions since the Eocene: Additional corrections for thermal contraction resulting from tectonic extension and for erosion and sedimentation since 34 Ma restore most of West Antarctica to above sea level, increasing total Antarctic land area by 10–20%. Because ice sheets have convex slopes, the potential increase in ice volume is larger than the increase in land area. Accounting for large changes in West Antarctic topography may resolve conflicts between ice models and data by demonstrating the possibility of an early, large West Antarctic Ice Sheet.