Collaborative Research: The Lake Superior Basin: Natural Geomorphic Experiment, Deepwater-Terminating Ice Stream, and Isostatically Adjusting Rift

合作研究：苏必利尔湖盆地：自然地貌实验、深水终止冰流和均衡调整裂谷

• 批准号: 2218457
• 负责人: Andrew Wickert
• 金额: $ 104.13万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2027-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2218457&HistoricalAwards=false
• 关键词: Collaborative; Research; Lake; Superior; Basin

Glaciers, lakes, rivers, and the solid Earth interact to reshape the surface environment. This applies to the Lake Superior Basin, a basin that formed as a rift in Earth's crust 1.1 billion years ago and since has hosted mountains, lakes, glaciers, rivers, and human inhabitants. Past and present lake-level change is responding to ancient ice-sheet retreat, whose unweighting of Earth's surface causes our planet's crust to bend and underlying mantle to flow. This project takes a multidisplinary approach to better understand the shaping of this continental landscape. The research team is reconstructing how the geological past of the Lake Superior basin impacts ongoing uplift and tilting of the land surface as well as surface processes including river erosion. Lake-level fall incites rivers to slice downwards through sediment and rock, while lake-level rise drowns the river mouths, causing deposition of gravel and sand. Mapping the three-dimensional patterns of the rivers encompassing the Lake Superior Basin, as they cut through materials ranging from soft mud to hard rock, is critical for understanding erosional processes. Additionally, dating landforms associated with past water-terminating glaciers and simulating their dynamics using computer models will improve scientists' ability to predict the fate of Earth’s existing ice sheets. Indigenous Ojibwe partners will consult in the research and share knowledge of both land and lake. Through a partnership with the Superior Hiking Trail Association, the project team will enhance outdoor recreation by providing public scientific knowledge of the region and its natural history. Finally, the research team is self-examining its approaches and practices to learn how to better include and support upcoming generations of Earth scientists.Through the nexus of the Lake Superior basin, this research is answering fundamental questions about river incision, (de)glacial landscape and lake-scape evolution, water-terminating glacier instabilities, and glacial isostatic adjustment. Lake Superior provides a uniquely suited testbed to advance each of these knowledge areas and to understand their feedbacks. Synchronous base-level fall on Lake Superior triggered river incision and knickpoint propagation across myriad lithologies, providing replicate natural experiments in erosional mechanics. The project team is applying traditional glacial geological approaches together with state-of-the-art topographic analyses to map lake-level evolution and the extent of glacial and fluvial process domains. Paleolake shorelines and spillways were modified by, and record, glacial isostatic adjustment, which can be further constrained via detailed seismic imaging of three-dimensional solid-Earth structure and extensive modern global navigation satellite system data. These data are being used to probe deeply into the mechanisms and feedbacks surrounding the marine ice sheet instability, critical for understanding the response and sensitivity of marine-terminating outlet glaciers and ice sheets. The research team is partnering with local nonprofit and government organizations to share the narrative of the Lake Superior region, integrate Indigenous knowledge, and build an inclusive field-research program whose goal is to invite a diversifying next generation into the geosciencesThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

冰川，湖泊，河流和地球相互作用以重塑地面环境。这适用于苏必利尔湖盆地，这是一个盆地，在地壳11亿年前形成了裂谷，此后一直托管山，湖泊，冰川，河流和人类居民。过去和现在的湖泊水平变化正在响应古老的冰片静修处，其对地球表面的稳定使我们的行星的外壳弯曲并在地下室下面流动。该项目采用多层方法来更好地了解这种连续景观的塑造。研究小组正在重建苏必利尔湖盆地的地质过去如何影响陆地表面的持续隆起和倾斜，以及包括河流侵蚀在内的表面过程。湖泊水平的秋天煽动河流通过沉积物和岩石向下切片，而湖泊水平的上升则吸引了河口，导致重力和沙子沉积。绘制包括苏必利尔湖盆地的河流的三维模式，因为它们通过从软泥到坚硬的岩石的材料切开，对于理解侵蚀过程至关重要。此外，与过去的水末期冰川相关的约会地貌并使用计算机模型模拟动态，将提高科学家预测地球现有冰盖的命运的能力。土著Ojibwe合作伙伴将在研究中进行咨询，并通过与Superior Hiking Trail Association建立合作伙伴关系，项目团队将通过提供该地区及其自然历史的公共科学知识来增强户外娱乐。最后，研究团队是自我检查的方法和实践，以学习如何更好地包括和支持即将到来的地球科学家。通过苏必利尔湖盆地湖的联系，这项研究正在回答有关河流切口，（de）冰川景观和湖泊景观进化的基本问题，供水终止冰川冰川Insportials Instibilitys iSpitions和glacial Ispatic Isportic isost isost isost。苏必利尔湖提供了一个独特的测试床，以推进这些知识领域并了解其反馈。同步的基础水平落在上司湖上的同步触发了无数岩性的河流切口和屈屈的传播，从而在侵蚀力学中提供了自然实验。该项目团队正在应用传统的冰川地质方法以及最先进的地形分析，以绘制湖泊水平的进化以及冰川和河流过程域的范围。旧光线海岸线和溢洪道是通过冰川等静态调节修改的，可以通过详细的地震成像对三维固体地球结构和广泛的现代全球导航卫星系统数据进行进一步限制。这些数据被用来深入探究围绕海洋冰盖不稳定性的机制和反馈，对于理解海洋末端出口冰川和冰盖的反应和灵敏度至关重要。研究团队正在与当地的非营利组织和政府组织合作，分享了苏必利尔湖地区的叙述，融合了土著知识，并建立了一个包容性的实地研究计划，其目标是使下一代多样化地进入地理学家奖，反映了NSF的法定任务，反映了通过使用基金会的智力效果和广泛的评估来诚实地支持NSF的法定任务。