Figure F2. Simulated initiation of East Antarctic glaciation in the earliest Oligocene using a coupled GCM-ice sheet model (from DeConto and Pollard, 2003a). These results are principally forced by gradual lowering of atmospheric levels of CO2 concentration in the simulated atmosphere. Note that the glaciation takes place in a "two-step" fashion reminiscent of the two-step δ18O increase recorded in benthic foraminiferal carbonates across the Eocene–Oligocene transition (e.g., Coxall et al., 2005). The first step results in glaciation in the Antarctic continental interior, discharging mainly through the Lambert Graben to Prydz Bay. The second step results in the initial connection and subsequent rapid expansion of the ice sheet, reaching sea level in the Wilkes Land at a later stage.
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