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

合作研究：用宇宙成因核素试纸限制最后一次冰消期间劳伦太德冰盖东南部变薄的时间和速率

• 批准号: 1603175
• 负责人: Jeremy Shakun
• 金额: $ 7.01万
• 依托单位: Boston College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1603175&HistoricalAwards=false
• 关键词: Collaborative; Research; Constraining; timing; rate

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.

全球海平面正在上升，而且还在加速上升，这对全球经济、地缘政治和安全产生了影响。控制未来海平面上升速度和幅度的最大、但也是最不确定的因素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为探索这个问题提供了一个绝佳的机会，因为它的特点是主要冰盖的崩塌和海平面突然的多米跃升，这些仍有待充分解释。该项目将重点重建新英格兰地区劳伦泰德冰原的三维崩塌，这是冰河时代最大的冰原。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——揭示冰盖表面何时下降到不同海拔以下，就像浴缸里的环一样。然后，这些垂直数据点将与该地区受到良好约束的水平冰缘退缩历史相结合，以产生随时间变化的冰盖崩塌的三维重建。这些重建将有助于评估该地区对冰川消融海平面上升的贡献，对海洋的淡水输入和对其循环的可能影响，以及冰盖如何对上次冰川消融的突然气候变化作出反应——所有这些对于测试用于预测未来的计算机模型都至关重要。

项目成果

Laurentide ice sheet thinning and erosive regimes at Mount Washington, New Hampshire, inferred from multiple cosmogenic nuclides

• DOI: 10.1130/spe.s.13487109
• 发表时间: 2020-10
• 期刊: Untangling the Quaternary Period—A Legacy of Stephen C. Porter
• 作者: Alexandria J. Koester;J. Shakun;P. Bierman;P. Davis;L. Corbett;B. Goehring;A. Vickers;S. Zimmerman