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，斯科特冰川是直接流入罗斯海的关键出口冰川，就在今天的西南极冰盖(WAIS)接地线以西。首要目标是了解末次冰川盛期(LGM)时及以来罗斯海地区WAIS形态的变化，并确定在罗斯湾观察到的全新世退缩是否已经结束或仍在进行。为了实现这些目标，将绘制与斯科特冰川有关的冰川和漂移序列的地图并确定日期，并测量冰层厚度、表面速度和表面质量平衡，以约束冰川的冰流模型。这个模型将被用来帮助解释年代地质序列。该项目的学术价值涉及更好地了解西南极冰盖，以及快速流动的出口冰川和冰流的变化活动如何对冰盖的质量平衡施加强有力的控制。以前的工作表明，罗斯海的基准线退缩持续到全新世晚期，并留下了持续消融冰川的可能性，这是长期趋势的一部分。位于接地线后面的出口冰川Reedy Glacier的研究结果表明，在过去的2000年里，退缩可能已经大幅放缓，甚至可能停止了。通过将斯科特冰川上的工作与芦荟冰川的最新数据结合起来，接地线的位置将被括起来，应该可以确定撤退是否真的已经结束或是否正在进行。这项工作的更广泛影响涉及增进对西南极冰盖的了解的社会意义，以确定它将如何应对当前和未来可能发生的环境变化。这项工作涉及西南极冰盖倡议的这一关键目标，以及关注冰盖历史和动态的国际极地年。这项工作将通过教育和培训一名本科生和两名博士生，通过课堂访问与K-12学生互动，基于网络的“考察”杂志，来自实地的信件，以及与教师的讨论来培养未来的科学家。该项目的结果将与之前南极洲的暴露年代测定结果一起公布在华盛顿大学宇宙核素实验室的网站上，该实验室还向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.