Measurements of past ice sheet elevations in interior West Antarctica

A Lateral moraine band on Mount Waesche, a volcanic nunatak in Marie Byrd L and, provides estimates of past ice sheet surface elevations in West Antarc tica. Helium-3 and chlorine-36 surface exposure ages indicate that the prox imal part of the moraine, up to 45 meters above the present ice surface, wa s deposited about 10,000 years ago, substantially Later than the maximum ic e extent in the Ross Embayment. The upper distal part of the moraine may re cord multiple earlier ice sheet high stands. A nonequilibrium ice sheet mod el predicts a delay of several thousand years in maximum ice levels at Moun t Waesche relative to the maximum ice extent in the Ross Sea. The glacial g eologic evidence, coupled with the ice sheet model, indicates that the cont ribution of the Ross Sea sector of the West Antarctic Ice Sheet to Holocene sea Level rise was only about 3 meters. These results eliminate West Antar ctic ice as the principle source of the large meltwater pulse during the ea rly Holocene.