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是完全消失，也将大幅缩小。该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)发生在约300年前小冰河时代冰川下游的冰川沉积冰川的年龄是多少？(2)过去10,000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环状冰川冰川的年代。将采用分级气候和冰川模拟战略，以评估在全新世期间改变大规模气候控制(冰盖、日照、温室气体)对冰川质量平衡和由此产生的波动的影响。这一研究战略为应用地质记录来限制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、坡面稳定性、水资源、河流泥沙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(本项目以外)，以改进对未来人类活动对高山冰川影响的评估，对海平面、水资源和社会对冰川美学质量的关注产生影响。这项研究包含了机构间合作的重要内容，并在美国地质调查局的支持下对模型作出了贡献。这项提议将通过包括一名博士生的培训、教育和研究贡献，并在数据获取、数据分析和建模方面进行强有力的交叉培训，直接为人力资源做出贡献。

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.