Erosion beneath Pleistocene Glaciers and Ice Sheets

该奖项将支持开发一种新方法来测量冰川和冰盖下的侵蚀速率。 该方法的基础上解释的深度剖面宇宙射线产生的核素（Be-10，Al-26和Cl-36）下的冰川基岩表面。 核素浓度、比值和剖面梯度对暴露和侵蚀历史很敏感。 我们将反演这些数据，以确定过去50 - 100万年的侵蚀。 为了验证该方法，我们将测量配置文件在上游和下游端的冰川地貌在东部缅因州，现有的理论预测不同的侵蚀过程和强烈对比的侵蚀速率。 这一工作将为冰川地貌景观演化研究提供一种定量方法。 这将使地貌学家重新审视有关更新世冰盖的侵蚀作用，特征冰川地貌的形成速率以及冰川谷剖面的起源等长期存在的问题。 这项工作的更广泛影响将包括：（i）研究生培训，（ii）本科生参与实地和实验室研究，（iii）与缅因州花岗岩工业博物馆合作，项目成果将用于解释冰川对周围景观的影响，（四）评估冰川侵蚀作为高纬度国家长期隔离核废料规划中的一个风险因素。

This award will support development of a new method to measure erosion rates beneath glaciers and ice sheets. The method is based on interpretation of depth profiles of cosmic-ray-produced nuclides (Be-10, Al-26 and Cl-36) beneath glaciated bedrock surfaces. Nuclide concentrations, ratios, and profile gradients are sensitive to the exposure and erosion history. We will invert these data to determine erosion over the past 0.5-1 million years. To verify the method we will measure profiles at up- and downflow ends of glacial landforms in eastern Maine, where existing theory predicts different erosion processes and strongly contrasting erosion rates. This work will provide a quantitative method for the study of landscape evolution in glaciated terrain. This will allow geomorphologists to re-examine long-standing questions concerning the erosional effects of the Pleistocene ice sheets, formation rates of characteristic glacial landforms, and the origin of glacial valley profiles. Broader impacts of the work will include: (i) Graduate student training, (ii) Undergraduate participation in field- and laboratory-based research, (iii) Collaboration with the Maine Granite Industry Museum, where project results will be used to explain the glacial imprint on the surrounding landscape, and (iv) Evaluation of glacial erosion as a risk factor in planning for long-term isolation of nuclear waste in high-latitude countries.