Collaborative Research: Testing Laurentide Ice Sheet Climate Response and Younger Dryas Trigger with Glacial Varves

合作研究：测试劳伦泰冰盖气候响应和新仙女木事件与冰川变化的触发

• 批准号: 1602789
• 负责人: Thomas Lowell
• 金额: $ 18.47万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing 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=1602789&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; Laurentide; Ice

This project has two objectives. 1) Document the response of the former ice sheet that covered the North American mid-continent to rapid climate changes that occurred at the end of the last ice age. Such a record enhances our ability to predict the response of ice sheets to modern climate change. 2) Test the role of increased freshwater influx to the Atlantic Ocean as a possible trigger for these rapid climate changes, specifically the cold interval known as the Younger Dryas. Modern freshening in the North Atlantic and Arctic Oceans has raised concerns that global warming driven increases in glacier runoff could trigger climate cooling. To evaluate models that use this event to assess the future response of the Atlantic Ocean to predicted freshening, the connections (if any) between freshwater discharge and routing before and during the Younger Dryas need to be resolved.The primary records that will be generated are varve thickness datasets from a large glacial lake, proximal to the former ice sheet. Glacial varves are yearly sediment couplets that appear similar to tree rings, and as such provide an annually resolvable record of how climate affected the ice sheet. The varves will be recovered by coring sediments from many lakes, spanning a broad region west of Lake Superior. By matching thickness patterns between all sites, a 5000+ year time series is anticipated. Working in collaboration with staff at Voyageurs National Park (Minnesota), this work will be showcased for the general public via a permanent indoor exhibit on varves as records of climate and environmental change.

这个项目有两个目标。1)记录覆盖北美中大陆的前冰盖对上一个冰期结束时发生的快速气候变化的反应。这样的记录增强了我们预测冰盖对现代气候变化的反应的能力。2)测试流入大西洋的淡水增加作为这些快速气候变化的可能触发因素的作用，特别是被称为年轻仙女木的寒冷时段。北大西洋和北冰洋的现代变暖引发了人们的担忧，即全球变暖导致的冰川径流增加可能会引发气候变冷。为了评估利用这一事件来评估大西洋未来对预测的淡水变化的响应的模型，需要解决年轻仙女木之前和期间淡水排放和路线之间的联系(如果有)。将产生的主要记录是来自前冰盖附近的一个大型冰川湖泊的不同厚度的数据集。冰川是一年一度的沉积物对，看起来类似于树的年轮，因此提供了气候如何影响冰盖的年度可解析记录。通过对苏必利尔湖以西大片地区的许多湖泊中的沉积物进行取芯，将可以恢复这些湖泊。通过匹配所有站点之间的厚度模式，预计将有5000年以上的时间序列。与旅行者国家公园(明尼苏达州)的工作人员合作，这项工作将通过一个永久性的室内展览向公众展示，作为气候和环境变化的记录。