Collaborative Research: Assessing the timing and characteristics of deglacial Laurentide Ice Sheet thinning in the northeast United States through paired data-model analyses

冰盖融化导致的海平面上升是未来气候变化最令人担忧的问题之一。然而，究竟有多少现代冰盖会对气候变暖做出反应还不确定。在最后一次盛冰期，劳伦泰德冰盖覆盖了北美的大部分地区，随着气候变暖，它的退缩对海平面上升起到了很大的作用。现有的数据限制了Laurentide冰盖过去冰盖边缘的位置和相关的冰盖退缩时间，但对冰盖厚度知之甚少，而冰盖厚度是估算冰量的关键参数。此外，冰盖在复杂地形上变薄的过程仍然不确定，这对现代冰盖的行为有直接影响。该项目将收集有关纽约阿迪朗达克山脉冰盖变薄的时间和速度的新数据，这些数据与现有数据一起，将被纳入一个高分辨率的冰盖模型，能够解决复杂地形上的冰流问题。这些新的分析将告诉我们，在最后一次冰川消退期间，横跨美国东北部的劳伦泰德冰盖的表面是如何变薄的，它是如何对气候做出反应的，以及这种冰盖变薄和退缩在过去海平面上升中所起的作用。与该项目相关的教育和社区外展将包括向社区大学学生提供课堂和实地地质学经验和培训。该项目将收集横跨纽约阿迪朗达克山脉的更新世劳伦泰德冰盖表面变薄的新地质年代数据。该研究将生成宇宙表面暴露数据，这些数据将约束Laurentide冰盖内陆部分冰盖在末次盛冰期后变薄的时间和空间变异性。这些数据将与一个三维热力学冰盖模型配对，该模型能够在亚公里尺度上解析冰流。模拟将集中在末次盛冰期和随后的冰川终止，并将在提出的地质数据的空间尺度上解决冰变薄、冰流和热状态的特征。配对数据模型分析解决了Laurentide冰盖变薄历史、冰盖退缩特征以及过去气候变化如何影响冰川消融的关键问题。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Sea-level rise from melting ice sheets is one of the greatest concerns of future climate change. However, exactly how much modern ice sheets will respond to a warming climate is uncertain. During the last glacial maximum, the Laurentide Ice Sheet covered a large portion of North America, and as it retreated in response to climate warming, it contributed greatly to sea-level rise. Available data constrain the location of past ice sheet margins and associated timing of ice retreat for the Laurentide Ice Sheet, but less is known about the ice sheet thickness, a key parameter for ice-volume estimates. Furthermore, the processes by which the ice sheets thinned over complex topography remain uncertain with direct implications for modern ice-sheet behavior. This project will gather new data about the timing and rate of ice sheet thinning in the Adirondack Mountains of New York, which, together with existing data, will be incorporated into a high-resolution ice-sheet model capable of resolving ice flow across complex terrain. These new analyses will inform how the surface of the Laurentide Ice Sheet across the Northeast United States thinned during the last deglaciation, how it responded to climate, and the role this ice sheet thinning and retreat played in past sea-level rise. Educational and community outreach associated with the project will include providing in-class and field geology experience and training to community-college students.This project will gather new geochronological data of surface thinning of the Pleistocene Laurentide Ice Sheet across the Adirondack Mountains of New York. The research will generate cosmogenic surface exposure data that will constrain the timing and spatial variability of Laurentide Ice Sheet thinning after the Last Glacial Maximum for an inland sector of the ice sheet. The data will be paired with a 3-D thermomechanical ice sheet model capable of resolving ice flow at sub-kilometer scales. The simulations will focus on the Last Glacial Maximum and subsequent glacial termination and will resolve characteristics of ice thinning, ice flow, and thermal regimes at the spatial scale of the geologic data proposed. The paired data-model analysis addresses key questions of Laurentide Ice Sheet thinning histories, characteristics of ice sheet retreat, and how past climate change influenced the deglaciation.This 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.