Collaborative Research: 3 Myr of Laurentide Ice Sheet History Inferred from Cosmogenic Nuclides in Ice-Rafted Debris

合作研究：根据冰筏碎片中的宇宙成因核素推断 3 Myr 的劳伦太德冰盖历史

• 批准号: 2116210
• 负责人: Marc Caffee
• 金额: $ 3.82万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-15 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2116210&HistoricalAwards=false
• 关键词: Collaborative; Research; Myr; Laurentide; Ice

The Laurentide Ice Sheet over North America caused large changes in climate and sea level as it grew and shrank over ice age cycles during the past three million years, but little is known about the ice sheet’s detailed history throughout this interval. This project will determine how big the ice sheet was through time using chemical markers in layers of sand on the seafloor that melted out of icebergs drifting from North America. This method provides a new way to learn about past changes in the Laurentide Ice Sheet and test ideas for how climate change and ice sheets affect each other. The results should help with predictions of sea-level rise far into the future due to global warming and melting polar ice sheets. This project will also educate and involve a wide range of people in climate science in several ways. Videos about the research will be sent to Boston Public Schools through the BoSTEM organization to help students in the area learn about careers in science. The researchers will participate in activities through the McAuliffe Center for Integrated Science Learning at Framingham State University to teach middle and high school students and teachers about climate change. College students will help with the research during summers through the Integrated Science for Society NSF Research Experience for Undergraduates at Boston College, which tries to find students from underrepresented minority groups or who are the first in their family to go to college and that do not have research possibilities at their school. Lastly, the project will support a female Ph.D. student already at Boston College and an M.S. student at the University of Vermont. The Laurentide Ice Sheet over North America was one of the largest drivers of climate and sea level over the ice age cycles of the past three million years, but its history over this interval is shrouded in uncertainty largely due to limitations of conventional geologic records. This project will take a new approach, measuring the concentrations of rare chemicals in quartz sand layers from ocean sediment cores that melted out of drifting North American icebergs. The chemistry of the sand reflects the history of North American ice sheet cover because the chemicals accumulate in land surfaces exposed to the atmosphere but radioactively decay away when the surfaces are buried by ice. Four sediment cores will be analyzed to reconstruct long-term Laurentide Ice Sheet evolution, and analyses of sand samples collected across eastern Canada will show how their chemistry records ice sheet variations over the most recent ice age cycle. Together with similar reconstructions produced over the past five years from Greenland and Antarctica, these records will provide a comprehensive picture of how these three ice sheets varied in the past and contributed to global sea level. The results will offer much-needed constraints to test theories and models of paleo-ice sheet change, useful for improving long-term future projections of ice sheets on Earth today. This project will increase literacy and diversity in climate science in multiple ways. “Science Bites” videos about the research will be distributed to Boston Public Schools through BoSTEM to demystify careers in science. Participation in ongoing efforts through the McAuliffe Center for Integrated Science Learning at Framingham State University will help educate middle and high school teachers and students on climate change. This project will support an existing female Ph.D. student at Boston College and an M.S. student at the University of Vermont. Summer undergraduate research assistants will be recruited through the Integrated Science for Society NSF REU at Boston College, which seeks to attract underrepresented minority and first-generation college students from schools with limited research opportunities.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.

北美上空的劳伦泰德冰盖在过去三百万年的冰河时代周期中不断扩大和缩小，导致了气候和海平面的巨大变化，但人们对冰盖在整个这段时期的详细历史知之甚少。利用从北美漂流而来的冰山融化的海底沙层中的化学标记，冰盖随着时间的推移变得越来越大。这种方法提供了一种新的方法来了解劳伦泰德冰盖过去的变化，并测试气候变化的想法。和冰盖这些结果将有助于预测未来由于全球变暖和极地冰盖融化而导致的海平面上升。该项目还将以多种方式教育和吸引更多人参与气候科学。该研究将通过 BoSTEM 组织发送到波士顿公立学校，以帮助该地区的学生了解科学职业。研究人员将参加弗雷明汉州立大学麦考利夫综合科学学习中心的活动，为中学生和高中生提供教学。和老师们关于气候变化的知识。大学生将在暑假期间通过波士顿学院的综合科学协会 NSF 本科生研究经验来帮助进行研究，该项目试图寻找来自代表性不足的少数群体的学生，或者是家庭中第一个上大学但没有资格的学生。最后，该项目将支持波士顿学院的一名女博士生和佛蒙特大学的一名硕士生。北美的劳伦泰德冰盖是气候和海洋的最大驱动因素之一。超过冰河时期的水平过去三百万年的周期，但其历史在很大程度上由于地质记录的限制而笼罩在不确定性中，该项目将采用一种新方法，测量来自海洋沉积物核心的石英砂层中稀有化学物质的常规浓度。从漂流的北美冰山中融化出来的沙子的化学成分反映了北美冰盖覆盖的历史，因为化学物质积聚在暴露于大气中的陆地表面，但当表面被冰掩埋时，会发生放射性衰变。分析重建劳伦泰德冰盖的长期演化以及对加拿大东部收集的沙子样本的分析将显示其化学成分如何记录最近冰河时代周期中的冰盖变化，以及过去五年从格陵兰岛和南极洲进行的类似重建。记录将全面了解这三个冰盖过去的变化以及对全球海平面的影响，这些结果将为测试古冰盖变化的理论和模型提供急需的约束，这对于改善长期的未来很有用。今天地球上冰盖的预测。该项目将以多种方式提高气候科学的素养和多样性，并将通过 BoSTEM 向波士顿公立学校分发有关该研究的“科学片段”视频，以揭开科学职业生涯的神秘面纱，通过麦考利夫综合科学学习中心进行。弗雷明汉州立大学将帮助对初中和高中教师和学生进行气候变化方面的教育，该项目将为波士顿学院的一名女博士生和佛蒙特大学的一名暑期本科生研究助理提供支持。通过波士顿学院 NSF REU 社会综合科学项目招募，该项目旨在吸引研究机会有限的学校中代表性不足的少数族裔和第一代大学生。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准。

项目成果

Laurentide Ice Sheet persistence during Pleistocene interglacials

更新世间冰期期间劳伦太德冰盖的持续存在

• DOI: 10.1130/g50820.1
• 发表时间: 2023-03
• 期刊: Geology
• 影响因子: 5.8
• 作者: LeBlanc, Danielle E.;Shakun, Jeremy D.;Corbett, Lee B.;Bierman, Paul R.;Caffee, Marc W.;Hidy, Alan J.
• 通讯作者: Hidy, Alan J.

Laurentide Ice Sheet persistence during Pleistocene interglacials

更新世间冰期期间劳伦太德冰盖的持续存在

• 发表时间: 2023-05
• 期刊: Geology
• 影响因子: 5.8
• 作者: LeBlanc1, Danielle;Shakun, Jeremy;Corbett, Lee;Bierman, Paul;Caffee, Marc;and Hidy, Alan
• 通讯作者: and Hidy, Alan