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

小型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将大大缩小，如果不是完全消失的话。该奖项将解决与了解美国西部高山冰川作用的历史和控制有关的两个基本问题：(1)300年前小冰河时期沉积的冰碛物的下游冰川沉积的冰碛物的年龄是多少？(2)在过去的10,000年（全新世）中，大规模气候控制的变化是如何影响冰川波动的？实现这些目标的方法将包括使用原位宇宙成因放射性核素和放射性碳技术系统地测定整个美国西部的冰斗冰川冰碛的年代。将采用一种分层次的气候和冰川建模战略，以评估全新世大规模气候控制（冰盖、日照、温室气体）变化对冰川物质平衡和由此产生的波动的影响。这一研究策略提供了一个杰出的方法，应用地质记录来限制高山冰川对辐射强迫的敏感性。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、边坡稳定性、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（本项目之外），以改善未来人类活动对高山冰川影响的评估，对海平面，水资源和社会关注冰川的美学品质的影响。这项研究包括一个强大的机构间合作的元素，与美国地质勘探局支持的建模贡献。该提案将通过包括一名博士的培训，教育和研究贡献直接促进人力资源。学生，在数据采集，数据分析和建模元素方面具有很强的交叉培训。

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.