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: 2116208
• 负责人: Jeremy Shakun
• 金额: $ 23.24万
• 依托单位: Boston College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2116208&HistoricalAwards=false
• 关键词: Collaborative; Research; Myr; Laurentide; Ice; 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.

在过去的三百万年中，北美的劳伦德冰盖在冰河时代的周期内生长和缩小，导致气候和海平面变化很大，但对整个间隔中冰盖的详细历史知之甚少。该项目将确定冰盖随着时间的流逝，使用在海底的沙子层中的化学标记物从北美漂移的冰山中融化。这种方法提供了一种新的方法来了解劳伦森冰盖的过去变化，并测试有关气候变化和冰盖如何相互影响的想法。由于全球变暖和熔化的极地冰盖，结果应有助于预测海平面上升的未来。该项目还将通过多种方式进行教育并涉及广泛的气候科学人员。有关该研究的视频将通过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。研究人员将通过弗雷明汉州立大学麦考利夫综合科学学习中心参加活动，以向中学生和老师讲授气候变化。大学生将在夏季通过社会综合科学在波士顿学院为本科生提供研究，该研究经验是在波士顿学院的本科生，该学院试图从代表性不足的少数群体中找到学生，或者是家庭中第一个上大学的学生，而他们在学校没有研究的可能性。最后，该项目将支持女性博士学位。已经在波士顿学院和硕士学位的学生佛蒙特大学的学生。在过去三百万年的冰河时代周期中，北美的劳伦德冰盖是最大的气候和海平面驱动因素之一，但是由于常规地质记录的局限性，它的不确定性笼罩在不确定性上。该项目将采用一种新的方法，测量海洋沉积物岩心的石英砂层中稀有化学物质的浓度，这些岩心是从北美冰山漂移的。沙子的化学反映了北美冰盖覆盖的历史，因为在暴露于大气的陆地上积累的化学物质，但是当冰建造表面时，放射性衰减。将分析四个沉积物核心，以重建长期的月球冰盖演变，对整个加拿大东部收集的沙子样本进行分析将显示其化学记录如何在最新的冰期循环中冰盖变化。以及过去五年中格陵兰和南极洲的类似重建，这些记录将提供全面的描述，说明这三个冰盖过去如何变化并为全球海平面做出了贡献。结果将提供急需的约束，以测试古冰纸变化的理论和模型，可用于改善当今地球上冰盖的长期未来项目。该项目将以多种方式提高气候科学的识字和多样性。有关这项研究的“科学叮咬”视频将通过Bostem分发给波士顿公立学校，以使科学领域的职业神秘化。通过弗雷明汉州立大学的麦考利夫综合科学学习中心参加正在进行的努力，将帮助教育中学和高中教师和学生有关气候变化的教育。该项目将支持现有的女性博士学位。波士顿学院的学生和硕士学位佛蒙特大学的学生。夏季的本科研究助理将通过波士顿学院的社会NSF REU的综合科学招募，该学院旨在吸引来自有限的研究机会的学校的人数不足的少数群体和第一代大学生。该奖项反映了NSF的法定任务，并认为通过该基金会的知识优点和广泛的Impacts creame criperia来评估。