Collaborative Research: Multidisciplinary Analysis of Antarctic Blue Ice Moraine Formation and their Potential as Climate Archives over Multiple Glacial Cycles

南极冰盖沉积的沉积物是其历史的档案，并帮助地质学家确定在过去的几十万年里，遥远的冰盖内部是如何变化的。该项目将重点研究南极横贯南极山脉中部阿切纳尔山（Mt. Achernar）蓝色冰区附近冰碛的形成和动力学（冰川表面的泥土和岩石的积累，或在冰川移动时被冰川推动）。这项研究将提高对这些冰碛形成的基本认识。现场工作将集中于对冰碛的内部结构进行成像，以确定它和其他类似的冰碛随着时间的推移形成的过程。其他分析将包括测量冰流和收集岩石样本，以确定碎屑沉积的时间和南极大陆深处沉积物来源的变化。该项目将为研究生和本科生提供古气候研究、地质学和数值模拟方法方面的培训。拟议工作的更广泛影响包括为研究生和本科生提供地球科学方面的培训，与新西兰和瑞典的同事合作，为来自美国的学生提供国际研究经验，以及由学生研究人员提供关于南极洲在全球环境中的作用的三个教育模块。该研究具有社会相关性和多学科性，其主题非常适合与公众分享。所有研究成果将通过及时发表在高影响力的同行评审期刊上向他人公开，所有数据将提交给国家冰雪数据中心，多余的样本将提供给美国极地岩石储存库。南极极地高原边缘对冰盖历史的直接观测对于测试数值冰盖模式至关重要，横贯南极山脉中部阿切纳尔冰碛复合体的横向广泛的蓝冰碛包含了多个冰川循环中独特的、几乎未开发的直接、准连续的冰盖变化记录。该项目的目标包括提高对蓝冰碛形成过程和速率的了解，以及确定地形、冰川学和气候对其演变的控制。在南极洲实地考察收集的数据包括：用探地雷达对内部冰结构进行成像，用全球定位系统（GPS）阵列测量冰流速度和方向，分析冰川冰中的碎片浓度和成分，用最先进的宇宙成因多核素分析确定冰碛碎片的暴露年龄，绘制边线和物源分析。在实地数据的约束下，将使用数值模型模拟来评估影响冰川流动变化的因素，这些变化可能会影响冰碛碎屑的积累。总之，新的数据和建模工作将改进蓝色冰碛形成的概念模型，从而使它们成为更好地了解冰盖历史的更有价值的代理。

Licht/1443433Sediments deposited by the Antarctic ice sheet are an archive of its history with time and help geologists to determine how the remote interior of the ice sheet has changed over the past several hundred thousand years. This project will focus on the formation and dynamics of moraines (accumulations of dirt and rocks that are incorporated in the glacier surface or have been pushed along by the glacier as it moves) near the blue ice area of Mt. Achernar in the central Transantarctic Mountains in Antarctica.. The study will improve basic understanding of the formation of these moraines. Fieldwork at the site will focus on imaging the internal structure of the moraine to determine the processes by which it, and others like it, form over time. Additional analyses will include measurements of ice flow and collection of rock samples to determine the timing of debris deposition and the changes in the sources of sediments from deep within the Antarctic continent. The project will provide both graduate and undergraduate students training in paleoclimate studies, geology, and numerical modeling approaches. The broader impacts of the proposed work include hands on training in the Earth Sciences for graduate and undergraduate students, collaboration with colleagues in New Zealand and Sweden to provide an international research experience for students from the US, and three educational modules to be delivered by student researchers regarding Antarctica's role in global environments. The research is societally relevant and multidisciplinary and the topics are ideal for sharing with the public. All research findings will be made publicly available to others via timely publication in high-impact, peer-reviewed journals and all data will be submitted to the National Snow and Ice Data Center, and excess samples will be provided to the U.S. Polar Rock Repository.Direct observations of ice sheet history from the margins of Antarctica's polar plateau are essential for testing numerical ice sheet models, and the laterally extensive, blue-ice moraines of the Mt. Achernar Moraine complex in the central Transantarctic Mountains contain a unique and nearly untapped direct, quasi-continuous record of ice sheet change over multiple glacial cycles. The project objectives include improved understanding of processes and rates of blue ice moraine formation, as well as identifying the topographic, glaciological, and climatic controls on their evolution. Data to be collected with fieldwork in Antarctica include: imaging of internal ice structure with ground-penetrating radar, measurement of ice flow velocity and direction with a global positioning system (GPS) array, analysis of debris concentration and composition in glacier ice, state-of-the-art cosmogenic multi-nuclide analyses to determine exposure ages of moraine debris, mapping of trimlines and provenance analysis. Numerical model simulations, constrained by field data, will be used to evaluate the factors influencing changes in glacier flow that potentially impact the accumulation of the moraine debris. All together, the new data and modeling efforts will improve conceptual models of blue ice moraine formation, and thereby make them a more valuable proxy for developing a better understanding of the history of the ice sheet.