Antarctica’s continental-scale ice sheets have evolved over the past 50 million years. However, the dearth of ice-proximal geological records limits our understanding of past East Antarctic Ice Sheet (EAIS) behaviour and thus our ability to evaluate its response to ongoing environmental change. The EAIS is marine-terminating and grounded below sea level within the Aurora subglacial basin, indicating that this catchment, which drains ice to the Sabrina Coast, may be sensitive to climate perturbations. Here we show, using marine geological and geophysical data from the continental shelf seaward of the Aurora subglacial basin, that marine-terminating glaciers existed at the Sabrina Coast by the early to middle Eocene epoch. This finding implies the existence of substantial ice volume in the Aurora subglacial basin before continental-scale ice sheets were established about 34 million years ago. Subsequently, ice advanced across and retreated from the Sabrina Coast continental shelf at least 11 times during the Oligocene and Miocene epochs. Tunnel valleys associated with half of these glaciations indicate that a surface-meltwater-rich sub-polar glacial system existed under climate conditions similar to those anticipated with continued anthropogenic warming. Cooling since the late Miocene resulted in an expanded polar EAIS and a limited glacial response to Pliocene warmth in the Aurora subglacial basin catchment. Geological records from the Sabrina Coast shelf indicate that, in addition to ocean temperature, atmospheric temperature and surface-derived meltwater influenced East Antarctic ice mass balance under warmer-than-present climate conditions. Our results imply a dynamic EAIS response with continued anthropogenic warming and suggest that the EAIS contribution to future global sea-level projections may be under-estimated.

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南极东部冰盖的形成和长期不稳定性

南极洲大陆尺度的冰盖在过去的 5000 万年里发生了演变。然而，冰附近地质记录的缺乏限制了我们对过去南极东部冰盖 (EAIS) 行为的理解，从而限制了我们评估其对持续环境变化的反应的能力。EAIS 位于极光冰下盆地内的海平面以下，位于海平面以下，这表明该流域将冰排到萨布丽娜海岸，可能对气候扰动很敏感。在这里，我们使用来自极光冰下盆地向海的大陆架的海洋地质和地球物理数据表明，在始新世早期至中期，萨布丽娜海岸存在海洋终止冰川。这一发现意味着在大约 3400 万年前大陆规模的冰盖形成之前，极光冰下盆地中存在大量冰体积。随后，在渐新世和中新世时期，冰从萨布丽娜海岸大陆架进退至少 11 次。与一半这些冰川作用相关的隧道山谷表明，在类似于预期的持续人为变暖的气候条件下，存在富含地表融水的次极地冰川系统。自晚中新世以来的冷却导致极地 EAIS 扩大，并且在极光冰下盆地集水区对上新世温暖的冰川反应有限。萨布丽娜海岸大陆架的地质记录表明，除了海洋温度，在比现在温暖的气候条件下，大气温度和源自地表的融水影响了南极东部冰块的平衡。我们的结果意味着 EAIS 的动态响应伴随着持续的人为变暖，并表明 EAIS 对未来全球海平面预测的贡献可能被低估了。