Collaborative Research: Peripheral East Antarctic Ice as a Unique Recorder of Climate Variability during the Last Interglacial

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。在最后一次间冰期（12.9万至11.6万年前），南极西部冰盖的空间范围目前尚不清楚，但这一信息对于预测冰盖在变暖气候下的未来稳定性至关重要。古气候记录和诸如沙尘之类的替代证据可以为过去的环境条件和冰盖覆盖提供信息。该项目将结合新的、高灵敏度的地球化学测量结果，这些测量结果来自于在艾伦山收集的南极冰层上的尘埃，并与现有的水同位素记录相结合，以记录上一个间冰期的气候和环境变化。然后将这些变化与地球系统模式对尘埃和水同位素的模拟进行比较，以确定过去的条件，并限制南极西部冰盖对变暖的敏感性。该项目将验证一个假设，即在最后一次间冰期在泰勒冰川另一个外围冰芯地点观测到的非典型的火山灰组成与南极西部冰盖空间范围的变化有关。本项目旨在描述第二次冰期-间冰期过渡期间矿物粉尘的运输特征。该团队将应用高精度地球化学技术，结合地球系统模型模拟，对在艾伦山矿区钻探的大容量、高分辨率冰芯进行分析，以便：(1)确定泰勒冰川间冰期冰中发现的火山灰特征是否也在艾伦山发现；(2)确定末次间冰期该地点可能的粉尘来源；(3)探测末次间冰期西南极冰盖减少时大气和环境的变化。该团队将对先前从艾伦山钻探的冰进行一系列测量，包括锶和钕的同位素组成、微量元素浓度、尘埃大小分布和冰芯尘埃的成像，以确认观测到的原始信号，并提供更广泛的尘埃运输空间重建。与此同时，研究小组将利用预测尘埃和水同位素的能力进行地球系统建模，以测试在几种可能的冰盖和淡水通量配置下尘埃输送的敏感性。通过比较沙尘重建和模型模拟，研究小组旨在阐明末次间冰期沙尘运输背后的驱动机制。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).The spatial extent of the West Antarctic Ice Sheet during the last interglacial period (129,000 to 116,000 years ago) is currently unknown, yet this information is fundamental to projections of the future stability of the ice sheet in a warming climate. Paleoclimate records and proxy evidence such as dust can inform on past environmental conditions and ice-sheet coverage. This project will combine new, high-sensitivity geochemical measurements of dust from Antarctic ice collected at Allan Hills with existing water isotope records to document climate and environmental changes through the last interglacial period. These changes will then be compared with Earth-system model simulations of dust and water isotopes to determine past conditions and constrain the sensitivity of the West Antarctic Ice Sheet to warming. The project will test the hypothesis that the uncharacteristically volcanic dust composition observed at another peripheral ice core site at Taylor Glacier during the last interglacial period is related to changes in the spatial extent of the West Antarctic Ice Sheet. This project aims to characterize mineral dust transport during the penultimate glacial-interglacial transition. The team will apply high-precision geochemical techniques to the high-volume, high-resolution ice core drilled at the Allan Hills site in combination with Earth system model simulations to: (1) determine if the volcanic dust signature found in interglacial ice from Taylor Glacier is also found at Allan Hills, (2) determine the likely dust source(s) to this site during the last interglacial, and (3) probe the atmospheric and environmental changes during the last interglacial with a diminished West Antarctic Ice Sheet. The team will develop a suite of measurements on previously drilled ice from Allan Hills, including isotopic compositions of Strontium and Neodymium, trace element concentrations, dust-size distribution, and imaging of ice-core dust to confirm the original signal observed and provide a broader spatial reconstruction of dust transport. In tandem, the team will conduct Earth system modeling with prognostic dust and water-isotope capability to test the sensitivity of dust transport under several plausible ice-sheet and freshwater-flux configurations. By comparing dust reconstruction and model simulations, the team aims to elucidate the driving mechanisms behind dust transport during the last interglacial period.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.