Determining Middle Miocene through Pliocene Changes in Paleo Ice-flow and Basal Ice Conditions in East Antarctica through Sedimentological Analyses of Core Samples

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该项目旨在研究从Prydz湾和罗斯海收集的沉积物岩心，以揭示南极东部冰盖的新近纪古气候历史。鉴于目前对全球气温大幅上升的测量和预测，调查南极东部冰盖对气候变化的敏感性及其在气候系统中的作用是至关重要的。以前气候变化时期的地质记录为实地真实模型预测提供了机会。该项目的科学目标是确定先前提出的中新世中期的转变，从一个更动态的湿基东南极冰盖到目前部分冻结到其床的半永久性冰盖。这种转变的时间和意义是有争议的，因为缺乏对年代确定的冰-近端沉积序列的定量研究。该项目利用双晶岩和砂岩的组成和物理性质来确定冰盖排水路径、古环境和基础冰况的变化，部分填补了这一空白。来自南极大陆边缘两个关键地区的研究结果将为我们了解南极东部冰盖在中新世中期过渡时期以及中新世晚期和上新世已知的变暖时期的行为提供洞见。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The project aims on studying sediment cores collected from Prydz Bay and the Ross Sea to unravel the Neogene paleoclimatic history of the East Antarctic ice sheet. In the light of current measurements and predictions of a substantial rise in global temperature, investigations into the sensitivity of the East Antarctic ice sheet to climate change and its role in the climate system are essential. Geological records of former periods of climate change provide an opportunity to ground truth model predictions. The scientific objective of this project is to identify a previously proposed middle Miocene transition from a more dynamic wet-based East Antarctic ice sheet to the present semi-permanent ice sheet that is partially frozen to its bed. The timing and significance of this transition is controversial due to a lack of quantitative studies on well-dated ice-proximal sedimentary sequences. This project partially fills that gap using the composition and physical properties of diamictites and sandstones to establish shifts in ice-sheet drainage pathways, paleoenvironments and basal ice conditions. The results from the two key areas around the Antarctic continental margin will provide insight into the behavior of the East Antarctic ice sheet across the middle Miocene transition and through known times of warming in the late Miocene and Pliocene.