Collaborative Research: Testing latest Pleistocene and Holocene glacial chronologies in the western United States with cosmogenic-nuclide and radiocarbon dating and models

小的高山冰川对气候很敏感，对未来全球变暖的预测表明，世界各地的许多高山冰川即使不会完全消失，也会大幅缩小。这个奖项将解决与理解美国西部高山冰川的历史和控制有关的两个基本问题：(1)冰川沉积的冰碛是在300年前小冰期沉积的冰碛的下游形成的，它们的年龄是多少？(2)最近~1万年（全新世）大规模气候控制的变化如何影响冰川波动？实现这些目标的方法将包括使用原位宇宙生成放射性核素和放射性碳技术系统地测定整个美国西部环状冰川冰碛的年代。将采用分层气候和冰川模拟策略来评估贯穿全新世的大尺度气候控制变化（冰盖、日照、温室气体）对冰川质量平衡及其波动的影响。这一研究策略为应用地质记录来约束高山冰川对辐射强迫的敏感性提供了一种杰出的方法。更广泛的影响。了解高山冰川对辐射强迫的敏感性对于景观外观、斜坡稳定性、水资源、河流沉积物负荷和生态系统健康具有重要意义。这里开发的建模方法将适用于（在本项目之外）改进对未来人类活动对高山冰川影响的评估，包括对海平面、水资源和对冰川美学质量的社会关注的影响。这项研究包含了机构间合作的重要元素，并在美国地质调查局的支持下为建模做出了贡献。该提案将通过包括一名博士生的培训，教育和研究贡献，直接为人力资源做出贡献，并在数据采集，数据分析和建模方面进行强大的交叉训练。

Small alpine glaciers are sensitive to climate, and projections of future global warming indicate that many alpine glaciers throughout the world will shrink considerably, if not disappear altogether. This award will address two fundamental questions relevant to understanding the history and controls of alpine glaciation in the western U.S.: (1) What is the age of moraines deposited by glaciers that occur immediately downstream to those deposited during the Little Ice Age ~300 years ago? (2) How have changes in large-scale controls of climate through the last ~10,000 years (Holocene) affected glacier fluctuations? Methods to be employed to accomplish these goals will involve systematically dating cirque-glacier moraines throughout the western U.S. using in-situ cosmogenic radionuclides and radiocarbon techniques. A hierarchical climate and glacier modeling strategy will be employed to evaluate the effects of changing large-scale climate controls through the Holocene (ice sheets, insolation, greenhouse gases) on glacier mass balance and resulting fluctuations. This research strategy provides an outstanding approach to applying the geologic record to constrain the sensitivity of alpine glaciers to radiative forcing. Broader Impact. Understanding the sensitivity of alpine glaciers to radiative forcing is of great interest with regard to landscape appearance, slope stability, water resources, sediment loading to rivers, and ecosystem health. The modeling approaches developed here will be applicable (outside of this project) to improve assessments of future anthropogenic impacts on alpine glaciation, with implications for sea-level, water resources, and societal concerns over the aesthetic qualities of glaciers. This study includes a strong element of inter-agency cooperation, with contributions for modeling supported by the USGS. This proposal will directly contribute to human resources by including the training, education, and research contributions of one Ph.D. student, with strong cross-training in elements of data acquisition, data analysis, and modeling.