East Antarctic Ice Sheet sensitivity under vulnerable conditions studied by combination of focused geophysical techniques

东南极冰盖(EAIS)保持相对稳定，而只有以海洋为基础的西南极冰盖容易受到当前不断变化的气候变化的影响，这一长期范例受到了挑战。南印度洋戴维斯海地区登曼冰川周围的东南极冰盖最近被确定为可能容易受到温暖的深水入侵。这与未来气候和海平面预测高度相关，因为Denman冰川潜在的冰块质量损失及其集水区腹地连接的冰块将导致海平面上升1.5至2米。过去暖期的行为记录将对这一脆弱性提供限制。评估过去的EAIS行为所需的基本数据知识之一是绘制和分析大陆架和隆起上的冰川-海洋沉积物，因为它们代表了过去冰盖动力学的档案。将于2024年初在RV Polarstein探险队PS141期间对丹曼近海大陆架和邻近出口冰川进行的全面浅层次表层水声和高分辨率地震到深盆地震勘探，将提供该项目的关键数据。重建的地震地层学与海洋钻探地点相连，以进行年代地层控制，将包含冰川从侵蚀到沉积的沉积模式，从而能够量化主要冰盖进退的时期。不同地震记录装置的组合将允许以最佳分辨率对不同深度的冰川结构进行成像。此外，深盆地地震成像的基底结构揭示了构造线条和断层，以及以前的冰盖接地钉点，表明裂谷盆地后来可能成为冰流的通道。主要工作将由两名博士生进行，一名在基尔大学，另一名在AWI，他们将非常密切地合作，因为不同的水声和地震数据集相辅相成。冰川动力学的重建，特别是在过去的暖期，例如渐新世、中新世、上新世暖期，以及最后一次间冰期和从最后一次冰盛期的退缩，将被用来为古冰盖模拟模拟提供参数。目的是通过与南极西部冰盖的观测和模型进行比较，揭示南极东部冰盖在暖期的脆弱性。该项目的结果将有助于将对东南极冰盖未来行为的预测提高到一个新的水平。

The long-standing paradigm that the East Antarctic Ice Sheet (EAIS) remains relatively stable, while only the marine-based West Antarctic Ice Sheet is vulnerable to the currently progressing climate change, has been challenged. The East Antarctic Ice Sheet around Denman Glacier in the Davis Sea sector of the southern Indian Ocean has recently been identified as potentially vulnerable to incursions of warm deep water. This is highly relevant for future climate and sea-level projections, because the potential ice mass loss of the Denman Glacier and connecting ice masses in its catchment hinterland would contribute to a sea-level rise of up to 1.5 to 2 m. Records of its behavior during past warm periods will provide constraints on this vulnerability. One of the basic data knowledge required for an assessment of past EAIS behavior is a mapping and analysis of the glacial-marine sediments on the continental shelf and rise as they represent archives of past ice sheet dynamics. Comprehensive shallow sub-surface hydroacoustic and high-resolution seismic to deep-basin seismic surveys on the continental shelf offshore Denman and neighboring outlet glaciers, to be acquired during RV Polarstern expedition PS141 in early 2024, will provide the key data of this project. The reconstructed seismic stratigraphy, linked to ocean drilling sites for chronostratigraphic control, will contain pattern of glacially transported sediments from erosion to deposition and, thus, enable a quantification of periods of major ice sheet advances and retreats. The combination of the different seismic recording setups will allow to image glacial structures at different depth at optimal resolution. In addition, the basement structures imaged by deep-basin seismics reveal tectonic lineaments and faults as well as former ice sheet grounding pinning points indicating possible extents of rift basins acting later as pathways for ice streams. The main work will be carried out by two PhD students, one at Kiel University and the other one at AWI, who will work very close together as the different hydroacoustic and seismic data sets complement each other. The reconstruction of glacial dynamics, in particular in past warm times, e.g. the Oligocene, Mid-Miocene, Pliocene warm periods as well as the last interglacials and retreat from the Last Glacial Maximum, will be used to feed the parameterization of paleo-ice sheet modelling simulations. The goal is to reveal the vulnerability of the East Antarctic Ice Sheet in warm periods in comparison to observations and models for the West Antarctic Ice Sheet. The results of this project will help lift the projections of the future behaviour of the East Antarctic Ice Sheet to a new level.