Collaborative Research:Grounding-line Retreat in the Southern Ross Sea - Constraints from Scott Glacier

该奖项支持一个研究斯科特冰川晚更新世和全新世变化的项目，斯科特冰川是一个关键的出口冰川，直接流入罗斯海，就在今天的南极西部冰盖（WAIS）基准线以西。总体目标是了解末次盛冰期（LGM）前后罗斯海区域WAIS结构的变化，并确定在罗斯海湾观测到的全新世退缩是否已经结束，或者是否仍在进行中。为了实现这些目标，与斯科特冰川相关的冰碛和漂移序列将被绘制和确定年代，冰厚度、表面速度和表面质量平衡将被测量，以约束冰川的冰流模型。这个模型将被用来帮助解释年代久远的地质序列。该项目的智力价值在于更好地了解南极西部冰盖，以及快速流动的出口冰川和冰流的活动变化如何对冰盖的质量平衡施加强有力的控制。先前的研究表明，罗斯海的基准线退缩一直持续到全新世晚期，并留下了作为长期趋势的一部分正在进行的冰川消融的可能性。来自里德冰川（接地线后面的一个出口冰川）的结果表明，在过去的2000年里，退缩可能已经大大减缓，甚至可能停止。通过将斯科特冰川的工作与里德冰川的最新数据结合起来，接地线的位置将被括起来，并且应该有可能确定退缩是否已经真正结束或是否正在进行。这项工作的更广泛影响涉及对南极西部冰盖的进一步了解的社会意义，以确定它将如何应对当前和未来可能的环境变化。这项工作解决了南极西部冰盖倡议的这一关键目标，以及国际极地年对冰盖历史和动态的关注。这项工作将通过教育和培训一名本科生和两名博士生，通过课堂访问、基于网络的“探险”期刊、实地信函以及与教师的讨论与K-12学生互动，培养未来的科学家。该项目的结果将与之前在南极洲的暴露年代测定结果一起发布在华盛顿大学宇宙核素实验室的网站上，该网站还为其他研究宇宙核素的科学家提供有关化学程序和计算方法的信息。

Hall/0636687This award supports a project to investigate late Pleistocene and Holocene changes in Scott Glacier, a key outlet glacier that flows directly into the Ross Sea just west of the present-day West Antarctic Ice Sheet (WAIS) grounding line. The overarching goals are to understand changes in WAIS configuration in the Ross Sea sector at and since the last glacial maximum (LGM) and to determine whether Holocene retreat observed in the Ross Embayment has ended or if it is still ongoing. To address these goals, moraine and drift sequences associated with Scott Glacier will be mapped and dated and ice thickness, surface velocity and surface mass balance will be measured to constrain an ice-flow model of the glacier. This model will be used to help interpret the dated geologic sequences. The intellectual merit of the project relates to gaining a better understanding of the West Antarctic Ice Sheet and how changing activity of fast-flowing outlet glaciers and ice streams exerts strong control on the mass balance of the ice sheet. Previous work suggests that grounding-line retreat in the Ross Sea continued into the late Holocene and left open the possibility of ongoing deglaciation as part of a long-term trend. Results from Reedy Glacier, an outlet glacier just behind the grounding line, suggest that retreat may have slowed substantially over the past 2000 years and perhaps even stopped. By coupling the work on Scott Glacier with recent data from Reedy Glacier, the grounding-line position will be bracketed and it should be possible to establish whether the retreat has truly ended or if it is ongoing. The broader impacts of the work relate to the societal relevance of an improved understanding of the West Antarctic ice sheet to establish how it will respond to current and possible future environmental changes. The work addresses this key goal of the West Antarctic Ice Sheet Initiative, as well as the International Polar Year focus on ice sheet history and dynamics. The work will develop future scientists through the education and training of one undergraduate and two Ph.D. students, interaction with K-12 students through classroom visits, web-based 'expedition' journals, letters from the field, and discussions with teachers. Results from this project will be posted with previous exposure dating results from Antarctica, on the University of Washington Cosmogenic Nuclide Lab website, which also provides information about chemical procedures and calculation methods to other scientists working with cosmogenic nuclides.