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

该项目有两个目标。1)记录覆盖北美中部大陆的前冰盖对上一个冰河时代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的作用，作为这些快速气候变化的可能触发因素，特别是被称为新仙女木的寒冷间隔。北大西洋和北冰洋的现代淡水化引起了人们的担忧，即全球变暖导致的冰川径流增加可能引发气候变冷。为了评估模型，使用这一事件来评估未来的大西洋预测的淡水化的反应，淡水排放和路由之间的连接（如果有的话）之前和期间的新仙女木需要resolved.The将产生的主要记录是纹层厚度数据集从一个大的冰川湖，接近前冰盖。冰川纹是每年的沉积物，看起来类似于树木的年轮，因此提供了气候如何影响冰盖的年度可分辨记录。这些纹管将通过对许多湖泊的沉积物取芯来恢复，这些湖泊横跨苏必利尔湖上级以西的广阔地区。通过匹配所有站点之间的厚度模式，预计将有5000多年的时间序列。这项工作将与Voyageurs国家公园（明尼苏达州）的工作人员合作，通过一个关于记录气候和环境变化的纹藻的永久室内展览向公众展示。

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.