Collaborative Research: Constraining the timing and rate of southeastern Laurentide Ice Sheet thinning during the last deglaciation with cosmogenic nuclide dipsticks

全球海平面正在上升，而且这种上升正在加速，对全球经济，地缘政治和安全产生影响。对未来海平面上升的速度和幅度的最大，但也是最不确定的控制是格陵兰岛和南极冰盖将如何应对持续变暖。最后一个冰河时代的结束提供了一个探索这个问题的绝佳机会，因为它的特点是主要冰盖的崩溃和海平面突然数米的跳跃，这些都有待于充分解释。该项目将侧重于重建劳伦泰德冰盖新英格兰部分的三维坍塌，劳伦泰德冰盖是冰河时代最大的冰块。这项研究将首先通过测量十几座大山两侧冰川巨石的表面暴露年龄来限制新英格兰冰盖变薄的时间和速度-揭示冰盖表面何时低于各种海拔，就像浴缸中的戒指一样。这些垂直数据点，然后将结合在该地区的约束良好的水平冰缘退缩的历史，产生三维重建冰盖崩溃随着时间的推移。这些重建将有助于评估该地区对冰消期海平面上升的贡献，淡水输入海洋及其对环流的可能影响，以及冰盖如何应对最后一次冰消期的突然气候变化-所有这些都对测试用于预测未来的计算机模型至关重要。

Global sea level is rising and this rise is accelerating, with implications for global economics, geopolitics, and security. The largest, but also most uncertain, control on the pace and magnitude of future sea level rise is how the Greenland and Antarctic Ice Sheets will respond to continued warming. The end of the last Ice Age provides an outstanding opportunity to probe this question since it featured the collapse of major ice sheets and abrupt mult-meter jumps in sea level that remain to be fully explained. This project will focus on reconstructing the three-dimensional collapse of the New England sector of the Laurentide Ice Sheet, the largest of the Ice Age ice masses. This research will first constrain the timing and rate of ice sheet thinning in New England by measuring surface exposure ages of glacial boulders down the sides of a dozen large mountains -- revealing when the ice sheet surface lowered below various elevations, much like rings in a bathtub. These vertical datapoints will then be combined with the well-constrained horizontal ice margin retreat history in the region to produce three-dimensional reconstructions of the ice sheet collapse through time. These reconstructions will enable an assessment of this region's contribution to deglacial sea level rise, freshwater input to the ocean and possible impacts on its circulation, and how the ice sheet responded to the abrupt climate changes of the last deglaciation -- all critical for testing computer models used to predict the future.