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

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。西南极冰盖在上一次间冰期(12.9万至11.6万年前)的空间范围目前尚不清楚，但这一信息对于预测气候变暖中冰盖未来的稳定性是至关重要的。古气候记录和替代证据，如尘埃，可以了解过去的环境条件和冰盖覆盖情况。该项目将结合在Allan Hills收集的南极冰尘的新的、高灵敏度的地球化学测量与现有的水同位素记录，以记录上一次间冰期的气候和环境变化。然后，这些变化将与地球系统模型对尘埃和水同位素的模拟进行比较，以确定过去的条件，并限制西南极冰盖对变暖的敏感性。该项目将检验这样一种假设，即在上一次间冰期在泰勒冰川的另一个外围冰芯地点观察到的不同寻常的火山尘埃成分与西南极冰盖空间范围的变化有关。该项目旨在描述倒数第二次冰川-间冰期过渡期间矿物粉尘的运移特征。该小组将对在阿伦山遗址钻探的大容量、高分辨率冰芯应用高精度地球化学技术，结合地球系统模型模拟来：(1)确定在泰勒冰川的间冰期冰中发现的火山尘埃特征是否也在艾伦山被发现，(2)确定上一次间冰期该地点可能的尘埃源(S)，以及(3)探测上一次间冰期期间随着南极西部冰盖减少而发生的大气和环境变化。该团队将开发一套对Allan Hills以前钻探的冰进行测量的方法，包括锶和钕的同位素组成、微量元素浓度、尘埃粒度分布以及冰芯尘埃的成像，以确认观察到的原始信号，并提供更广泛的尘埃传输的空间重建。同时，该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，以测试在几种合理的冰盖和淡水通量配置下尘埃传输的敏感性。通过比较尘埃重建和模型模拟，该团队旨在阐明上一次间冰期尘埃输送背后的驱动机制。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.