SGER: Using 4He/3He thermochronometry to quantify the rate and timing of Canadian Shield fjord incision

利用4He/3He热计时技术量化加拿大Shieldfjord切割的速率和时间--地形起伏发展与气候变化之间的关系已成为地球科学中的一个重要课题。将地貌的产生与气候变化联系起来，例如第四纪冰期的开始，依赖于对冰川侵蚀模式和时间的定量了解。尽管活动造山带中的高山冰川侵蚀一直是最近研究的重点，但可以说，冰川切割最强烈的地方--自冰河时代开始以来一直被插入1公里深的峡湾--仍有待详细研究。峡湾插入的速率和空间格局以及冰盖动力、地形和冰川侵蚀过程之间的反馈是第四纪气候和景观变化的重要组成部分。这项研究的目的是量化劳伦德冰盖插入加拿大北部地盾的峡湾的时间和空间演变。研究小组将应用一种新的工具，4He/3He热计时仪，来量化克莱德湾的形成速度和模式。克莱德湾是巴芬岛上的一个峡湾，与环绕着加拿大盾的数十个其他峡湾一样，也是格陵兰和诺威周围峡湾的代表。4He/3He热计时仪的样本将记录克莱德湾的热史，这反过来将限制峡湾的长期切割历史。将收集峡湾横截面和峡湾长剖面样本集，这将可能量化峡湾的垂直挖掘和向前传播速率。拟议中的研究结果代表着该团队朝着改善对冰盖动力学和景观演变之间的反馈的理解的长期目标迈出了关键的一步。峡湾的侵蚀历史是数值冰盖模拟的关键观测约束，目的是解决地形和冰盖行为之间的复杂反馈问题。冰盖的侵蚀史对冰盖的厚度和形状、主要冰流的位置及其起始区、海洋冰盖边缘的整体稳定性和结构具有重要的控制作用。广泛的影响--这项研究将培训一名职业生涯早期的科学家(Briner)，并将向布法罗大学和科罗拉多大学的研究生和本科生介绍新颖的应用和令人兴奋的地球科学问题。这一奖项下的研究活动将通过将目标和最终成果翻译成因努基特语，制作描述研究的海报，并在努纳武特首府伊卡卢伊特和我们拟议的实地基地克莱德河举办公开讲座，使土著人民能够了解。该团队将继续他们与克莱德河人合作的传统，包括导游、猎人和捕猎者协会以及高中生。此外，安德森将继续努力通过参与美国国家公园的护林员培训项目来教育更广泛的公众冰川景观的演变，在这些项目中，冰川在雕刻冰川景观方面发挥了重要作用，并生成了模拟，这些模拟可以作为K-12和大学课堂的教育工具，也可以作为国家公园展示的动态内容。

Using 4He/3He thermochronometry to quantify the rate and timing of Canadian Shieldfjord incisionIntellectual Merit - The relationship between topographic relief development and climatechange has emerged as a critical topic in earth science. Linking relief generation to climatechange, e.g. the onset of the Quaternary ice age, relies on a quantitative understanding of thepattern and timing of glacial erosion. Although alpine glacial erosion in active orogenic belts hasbeen the focus of recent research, fjorded continental margins, arguably the sites of the mostintense glacial incision, in which fjords 1 km deep have been inserted since the ice ages began,have yet to be examined in detail. The rates and spatial patterns of fjord insertion, and thefeedbacks between ice sheet dynamics, topography, and glacial erosional processes are importantcomponents of Quaternary climate and landscape change. The aim of this research is to quantifythe temporal and spatial evolution of a fjord inserted into the northern Canadian Shield by theLaurentide Ice Sheet. The research team will apply a novel tool, 4He/3He thermochronometry, toquantify the rate and pattern of formation of Clyde Inlet, a fjord on Baffin Island typical ofdozens of other fjords rimming the Canadian Shield, and representative of fjords around bothGreenland and Norway.Samples for 4He/3He thermochronometry will document the thermal history of Clyde Inlet,which in turn will constrain the long-term incision history of the fjord. Both fjord cross-sectionand fjord long-profile sample sets will be collected, which will potentially quantify both verticalexhumation and headward propagation rates of the fjord. The results of the proposed researchrepresent a critical step toward the team's longer-term goal of improving the understanding ofthe feedbacks between ice sheet dynamics and landscape evolution. The erosional history of thefjord is the key observational constraint for numerical ice sheet simulations aimed at solving thecomplex feedbacks between topography and ice sheet behavior. The erosional history of fjordsexerts a significant control on ice sheet thickness and configuration, the locations of major icestreams and their onset zones, and the overall stability and configuration of marine-basedmargins of ice sheets.Broader Impacts - This research will train one early-career scientist (Briner) and will exposegraduate and undergraduate students at the Universities of Buffalo and Colorado to novelapplications and exciting earth science problems. Research activities under this award will bemade accessible to indigenous peoples by translating the goals and eventual results into Inuktitut,making posters that describe the research, and by offering public lectures in Iqaluit, the capital ofNunavut, and at Clyde River, our proposed field base. The team will continue their tradition ofworking with the people of Clyde River, including guides, the Hunter's and Trapper'sAssociation and high school students. In addition, Anderson will continue his efforts to educatethe broader public about glacial landscape evolution through involvement in ranger trainingprograms at US National Parks in which glaciers have played significant roles in sculpting thelandscape, and in generation of simulations that can serve both as educational tools in K-12 andcollege classrooms, and as dynamic content in National Park displays.