History of ice sheet elevation in East Antarctica: Paleoclimatic implications

The multi-disciplinary study of past ice surface elevations in the Grove Mountains of interior East Antarctica provides direct land-based data on the behavior of the East Antarctic Ice Sheet since the Pliocene. The glacial geology, the ages of cold desert soils, the depositional environment of younger moraine sedimentary boulders and their spore–pollen assemblages combine to imply a possible significant shrinkage of the Ice Sheet before the Middle Pliocene Epoch, with the Ice Sheet margin retreating south of the Grove Mountains (∼ 450 km south from its present coastal position). Exposure age measurements of bedrock indicate that the elevation of the ice surface in the Grove Mountains region subsequently rose at about mid-Pliocene to at least 200 m higher than todayʹs levels. The ice surface then progressively lowered, with some minor fluctuations. Middle to Late Pleistocene exposure ages found on the lowest samples, at the ice/bedrock contact line, indicate a long period with ice surface elevations kept at the current level or complex fluctuation history during the Quaternary Epoch.